Amphenol TCS
Design For Manufacturability Guideline
TB-2083
Amphenol TCS
Backplane Assembly
Design for Manufacturability Guidelines
This document contains proprietary information that is not to be used in any
way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
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Amphenol TCS
Design For Manufacturability Guideline
TB-2083
Specification Revision Status
SCR No.
Description
Initial
Date
"-"
"A"
34696
37667
J. Proulx
M. Wilensky
4/4/01
2/4/02
“B”
44537
J. Scanlan
6/15/04
"C"
S0081
Initial Release
Updated DFM requirements to cover
capabilities and limitations of new
automated holtite insertion machine
Added notes to checklist, page 74, to
confirm internal component specification
match customer approved vendor list (AVL)
Replace template format
M.Lee
02-03-06
Revision
Table of Contents
1.0
DFM Guideline Introduction
1.1 Scope
1.2 DFM Introduction
1.3 Benefits of DFM
1.3.1 Product Cost
1.3.2 Engineering Change Cost
1.3.3 Quality
1.3.4 Time to Market
1.4 New Product Development
1.4.1 Design Concept
1.4.2 Product Design
1.4.3 Proto Build
1.4.4 Pilot Build
1.4.5 Production
2.0
Introduction - AMPHENOL TCS Manufacturing Process
2.1 Benefits of Automation
2.1.1 Defect Tracking Definition
2.1.2 Design Complexity
2.1.3 Design Density
2.2 Manufacturing Process Flow
2.2.1 Alternative Process Flow
2.3 Manufacturing Process Flow - Cost Drivers
2.3.1 Surface Mount Process Flow
2.3.2 Press Fit Process Flow
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Amphenol TCS
3.0
4.0
Design For Manufacturability Guideline
TB-2083
PCB Mechanical Requirements
3.1 PCB Preferred Shape
3.1.1 PCB Acceptable Shape
3.1.2 Minimum Acceptable Length to Width Ratio
3.1.3 PCB - Non Preferred Shape
3.2 PCB Size and Edge Clearance
3.2.1 Automated Press-Fit Detailed Placement Envelop
3.3 Tooling Hole Requirements
3.4 Fiducial Mark Requirements
3.4.1 Global and Local Fiducial Requirements - SMT Only
Component Guideline
4.1 Component, Package and Source Standards
4.2 SMT & Through Hole Solder Component Sizes and Lead Pitches
4.2.1 SMT Component - Auto Placement Compatibility
4.2.2 SMT Components - Preferred
4.2.3 SMT Components - Acceptable
4.2.4 SMT Components - Non-Preferred
4.2.5 Through Hole Solder Components
4.3 Press-Fit Component Sizes
4.3.1 Press-Fit Pin and Component Requirements
4.3.2 Press-Fit Components - Preferred Pin Design
4.3.3 Press-Fit Components - Preferred Design
4.3.4 Press-Fit Components - Acceptable
4.3.5 Press-Fit Components - Non-Preferred
4.4 Threaded Assembly Process Requirements
4.4.1 Threaded Assembly Components
4.5 Component Lead Plating
4.6 Orientation Marking
4.7 Assembly Process Compatibility
4.7.1 Moisture Sensitivity
4.7.2 Water Wash Compatibility
4.7.3 Wave Solder Exposure Conditions
4.7.4 Reflow Solder Exposure Conditions
4.8 Component Carrier Specifications
4.8.1 Material Specifications for Carrier tape and Cover tape
4.8.2 Label Requirements
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Amphenol TCS
5.0
6.0
Design For Manufacturability Guideline
TB-2083
PCB Layout (Placement and Spacing) Requirements
5.1.0 Top and Bottom Side Placement and Distribution - SMT & Through Hole
Solder
5.1.1 Top and Bottom Side Placement - Press Fit
5.1.2 Backplane Connector Length Distribution - Press Fit
5.2.0 Top Side Spacing Requirements - SMT & Through Hole Solder
5.2.1 Bottom Side Spacing Requirements - SMT & Through Hole Solder
5.2.2 Press-Fit Spacing Requirements - Single Sided Press-Fit to All Others
5.2.3 Center-Plane Press-Fit Preferred Assembly Methods
5.2.4 Center-Plane Press-Fit Spacing Requirements - Press-Fit to All Others
5.3.0 Hole Size and Clearances - Through Hole Solder
5.3.1 Hole Size and Clearances - VHDM & Press-fit
PCB Routing and Design
6.1.0 Via Placement and Clearances
6.1.1 Test Point Placement and Clearances
6.1.2 Thermal Relief
6.2 Conductor Routing
6.3 PCB Markings - Silkscreen & Etch Requirements
6.4 Solder-Mask and Surface Plane Requirements
6.5 PCB Finish Requirements
Appendix:
I.
Design Review Check Sheet - used for design reviews.
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Amphenol TCS
1.0
Design For Manufacturability Guideline
TB-2083
Document Introduction
This document is intended to provide information and design criteria that will promote automation,
cost and cycle time reduction, and help produce designs that will yield quality products assembled at
Amphenol TCS. This document is not intended to define the limitations of the
assembly process at AMPHENOL TCS, nor is it intended to constrain designs.
1.1
Scope
This document has been prepared to communicate the manufacturing capabilities and design for
manufacturability (DFM) guidelines concerning Backplane Assembly - including Press-Fit assembly
processes, Surface Mount Technology (SMT) assembly and Through Hole Solder assembly. This guideline
also "touches on" in-circuit test (ICT) and PCB fabrication (TCO), BUT only as it relates to assembly.
Updates and revisions will be issued on a continuous basis to expand the guidelines, address changes in
technology and cover modifications and/or additions to Amphenol TCS current manufacturing capability.
1.2
DFM Introduction
Section one explains the concepts of Design for Manufacturability. It illustrates where and when
costs occur in the development cycle, and how "Time to Market" is affected by DFM. It also flows out the
development cycle, showing the DFM process steps, with required inputs and deliverables for each step.
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1.3
Design For Manufacturability Guideline
TB-2083
Benefits of DFM
DFM is the sharing of manufacturing guidelines developed from industry standards and the
knowledge gained from design and production. Applying these guidelines concurrently to new product
development will continuously reduce cost and improve quality. The following graphs illustrate how
applying the DFM guidelines to new product development has a direct positive impact on cost, quality and
time to market. The DFM impact on cost includes the product cost and the cost of engineering changes.
1.3.1
Product Cost
Eighty percent of a new product cost is committed by the time it starts prototype build.
Consequently, the greatest opportunity to reduce the cost of a product is in the design phase. Early DFM
involvement in new technologies, component packages and processes, reduce the product cost by correcting
the design and manufacturing issues prior to prototype build.
100
% of Cost Committed
90
80
70
60
50
40
30
20
10
0
Design Concept
Product Design
Proto Build
Production
$ Committed
Greatest Opportunity to Influence Product Cost
Source: D. Kuk, EP&P 5/93
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1.3.2
Design For Manufacturability Guideline
TB-2083
Engineering Change Cost
Applying the DFM guideline early in the design concept phase, reduces the cost and labor resources
required for engineering changes. The graph below illustrates how the total cost of an engineering change
can increase by several orders of magnitude when it is made late in the product development cycle.
1000x
100x
Dollars
and People
10x
1x
Design Concept
Product Design
Proto Build
Production
Source: Mentor Graphics Corp. Market Research
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1.3.3
Design For Manufacturability Guideline
TB-2083
Quality
By implementing the DFM guidelines and addressing exceptions to the DFM guidelines early in the
development cycle, the risk of hidden problems can be eliminated. The use of the DFM guidelines will help
to reduce the number of engineering changes at product introduction and will increase long term product
reliability. This idea is further illustrated below. When DFM engineering is an integral part of product
development, the majority of the engineering design changes are identified early in the development cycle.
1.3.4
Time to Market
A major advantage of reducing the development time for new products is the ability to consistently
meet the time to market goals. Through early DFM involvement, product development time can be
significantly reduced as shown on the following graph. It illustrates that although the Design Concept phase
is longer - due to the implementation of DFM requirements, they are significantly easier to implement at this
stage. This reduces the changes, and time involved in the remaining cycles - therefore reducing the overall
time to market.
Typical Product
Design
DFM Engineering
Design
Concept
Initial
Design
3%
27%
20%
13%
Product Design/
Proto Build
Production
55%
15%
22%
5%
40% Time Savings
Source: Concept Engineering: Product Development, D.Carter & B.Baker
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1.4
Design For Manufacturability Guideline
TB-2083
New Product Development
The chart below illustrates how concurrent engineering is part of the DFM process for new product
development. The anticipated input details what information is required for each process step. The
deliverables highlight the output from each process step
DFM Process
Deliverables
Cost/Yield Targets
Design Objectives
New Technology Requests
Design
Concept
Estimated Product Cost
DFM Recommendations
Technology Assessment
BOM
CAD files
New Process Requirements
Product
Design
Product Cost Tracking
In Process Artwork Review
Process/Equipment Development
Inputs
Proto Request
MRP Demand
Released BOM
Documentation Package
Manufacturing Process Spec.
Assembly Aids
Tooling
Documentation and tooling are
released to manufacturing
Proto
Build
Pilot Build
(Pre-Production)
Production
Process Development
Initial Build
Final Costing
Process Feedback
Time Standards
Volume Capable Production
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1.4.1
Design For Manufacturability Guideline
TB-2083
Design Concept
The DFM deliverables at the initial design concept phase of a new product are presented below.
Product design information is shared early in the development phase where concerns affecting Cost, Quality
and Time to Market can be addressed.
Deliverables
Definitions
•
- Identify new components, technologies and possible new
process/equipment requirements.
New Technology
Assessment
- Identify how these new components or technologies will impact
existing processes and equipment.
- In addition, cost and time to procure/develop new processes is defined.
•
Initial Cost Analysis/
Assembly Options
- Preliminary review of assembly process. Determine initial cost.
- Determine cost drivers/problems and investigate cost reduction
solutions.
- Determine percent automation.
•
1.4.2
DFM Recommendations
- DFM recommendations and options submitted. Initial cost estimates
revised based on DFM recommendations to achieve design objectives.
Product Design
DFM deliverables at the product design concept phase of a new product are presented below. Design
issues affecting the DFM guidelines are resolved prior to component placement and trace routing.
Subsequent DFM issues may be addressed anytime a significant change is required.
Deliverables
Definitions
•
Cost Tracking
- Pre-artwork cost based on initial BOM only. Cost is revised based on
completed artwork.
•
In Process Artwork
Review
- First review of artwork component layout prior to trace routing. DFM
check on component shapes, spacing, fiducial placements and
mechanical specifications.
- Final review is performed on completed artwork package. Checking
items such as: verify silk-screen markings, component placement, trace
routing, via/test point placement, assembly layers.
•
New Process
Development
- New processes developed/new equipment installed as required.
- Custom tooling requirements procured.
- Training performed and processes documented.
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1.4.3
Design For Manufacturability Guideline
TB-2083
Proto Build
The DFM deliverables at the prototype build phase of a new product are presented below. Any DFM
issues affecting manufacturing can be identified during the prototype build and resolved prior to
manufacturing release.
Deliverables
Definitions
•
- Assembly instructions, drawing aids, solder paste stencil, wave solder
fixtures and press-fit tooling, are created, as required.
Process Development
- All programming requirements for assembly equipment are finalized.
•
Initial Build
- Initial Build is completed and all Manufacturability issues are
documented and reported back to Design Engineering.
- Manufacturing Process Specs for new processes, if required, are
released covering equipment use, procedures and process recipes.
- New process tooling is released.
•
1.4.4
Final Costing
- Final cost is defined based on actual build.
Pilot Build
The DFM deliverables at the pilot build phase of a new product are presented below. Any process,
documentation or time standard issues can be identified and resolved prior to manufacturing release.
Deliverables
Definitions
•
- Fine-tuning to the process flow, such as line balancing, is done at this
time.
Process Feedback
- Fine-tuning of process documentation, new equipment specs and visual
aids are completed.
•
1.4.5
Time Standards
- Time standards are finalized to reflect finalized process flow
Production
Documentation, processes, tooling and time standards are released to manufacturing. The product is
considered to be routinely reproducible following standard AMPHENOL TCS processes.
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2.0
Design For Manufacturability Guideline
TB-2083
Introduction - AMPHENOL TCS Manufacturing Process
This section provides "industry standard" data, and uses it to explain the various manufacturing
processes used at AMPHENOL TCS along with their associated cost, yield and cycle time features.
Manufacturing cost drivers are identified in section 2.3 along with possible alternative solutions.
AMPHENOL TCS’s approach on new designs strives for the highest level of automation achievable in a
single sided Press-Fit and/or SMT configuration. Single sided assembly represents the lowest cost, shortest
cycle time and highest yield achievable.
2.1
Benefits of Automation
Manually assembled components and labor-intensive mechanical assemblies should be designed out.
Designs that are optimized for automation have higher yield, lower cost and will produce shorter cycle times.
In addition, ECO’s can be incorporated into new revisions in a timely manner. The table below highlights
the benefits of using an automated process over a manual process in assembly.
Automated
Processes
Manual
Processes
Yield
DPMO
(Defects Per Million Opportunities)
Cost
Cycle Time
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2.1.1
Design For Manufacturability Guideline
TB-2083
Defect Tracking Definition
The tables below summarize the findings from the Ceeris 1996 benchmark study for manufacturing
process quality. The study findings are based on facilities recognized as world-class manufacturers.
Assembly process quality is measured in number of defects per million opportunities (DPMO).
# of Defects
DPMO =
* 10
6
# of Opportunities
# of Opportunities = Sum of (all connection points + Parts )
2.1.2
Design Complexity
Design complexity is the number of defect opportunities per board. The table below shows that
among world class manufacturers, manufacturing performance improves as the number of opportunities for
defects decrease.
Board Complexity
(Opportunities)
Quality (DPMO)
<3000
63
>3000
84
CEERIS International, inc., World Class Process Quality Benchmarks, 1996
2.1.3
Design Density
Design density is the number of defect opportunities per square inch of board. The table below
shows that among world class manufacturers, high-density board designs have a higher defect rate.
However, this increase is small (22%) when compared to the increase in DPMO when going from single
sided to two sided SMT (60%).
Components/sq. in
DPMO
<50
65
>50
79
CEERIS International, inc., World Class Process Quality Benchmarks, 1996
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2.2
Design For Manufacturability Guideline
TB-2083
Manufacturing Process Flow
AMPHENOL TCS's manufacturing process flow is shown below. The preferred AMPHENOL TCS
processes are noted Note: This is a high-level flow chart - detailed requirements start in Section 3
Kit
Parts are picked from the stockroom by work-order
SMT Process - Single side
Screen
Print
Solder Paste Application - Solder paste is a homogeneous mixture of solder and flux.
Stencil printing is a process where solder paste is forced through apertures on a stainless
steel stencil, onto PCB surface pads.
Component
Placement
Automated Component placement equipment places SMT components on the printed
circuit board surface.
Reflow
Pass-thru reflow ovens heat the printed circuit board to a desired temperature which
melts the solder in the solder paste, and forms the solder joints.
Clean
Cleaning is used to remove contaminants and flux residues left during the screen-print
and reflow process steps. Cleaning methods used - Saponified Aqueous cleaning: water
mixed with surfactant, with de-ionized rinse.
SMT Process - Double Side
SMT process
Bottom side
For double-sided SMT assembly, two complete passes are required thru the SMT
process. Each pass is a duplicate of the process above. Note: When running a double
sided board, bottom side is processed first, then the board is flipped, and top side is
processed.
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Design For Manufacturability Guideline
TB-2083
Through Hole Solder
Hand
Insertion
Wave
Solder
Selective
Wave Solder
Clean
Through Hole Solder components are inserted, clinched, and cut to length by hand.
(AMPHENOL TCS does not use automated placement equipment for these components)
Wave Soldering applies molten solder to the secondary side of the printed circuit board,
filling the plated thru holes with solder to form solder joints with the component leads.
(Hand Soldering is a non-preferred alternate method, when wave solder is not possible.)
This step requires specialized fixturing, which is required to mask off secondary side
SMT and Press fit component holes
Cleaning is used to remove contaminants and flux residues left during the screen-print
and reflow process steps. Cleaning methods used - Saponified Aqueous cleaning: water
mixed with surfactant, with de-ionized rinse.
Press Fit Process - Single Side
Component
Placement
Light Assisted
Component
Seating
Automated
Press
This is a Semi-automated step, where press-fit components are hand placed using a light
guided placement system. The components are not fully seated at this time.
Automated equipment that loads the backplane into the machine, and using specialized
tooling, seats the components into the board.
Note: AMPHENOL TCS has semi-automated press fit equipment, which has less
design constraints, but is less preferred than the automated equipment.
Press Fit Process - Double Side
Press Fit
process
second side
For double-sided Press Fit assembly, two complete passes are required thru the process.
The second pass is a duplicate of the process above, but requires more PCB edge
clearance.
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Design For Manufacturability Guideline
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Threaded Assembly
Mechanical
Hand
Assembly
Threaded assembly of PCB components, is a non-preferred manual process, which is
sometimes unavoidable in backplane assembly. Although the assembly is done by hand,
AMPHENOL TCS uses pre-set torque drivers to provide consistent torque values for
hardware assembly.
To In-Circuit
Test
2.2.1
Alternative Process Flow
Holtite® and Through Hole Component
P
Holtite® technology is an alternative to the Through Hole Solder process, where Holtite® sockets
are pressed into the PCB, and then Through Hole component leads are pressed into the Holtite®
sockets - no soldering is required. This process should be used as an alternative in the following
situations:
If
Then
.070”> PCB thickness > .200”
Only if all other SMT and press fit component options have been exhausted..
If
Then
PCB thickness > .200”
Only if all other press fit component options have been exhausted.
Note: This process cannot be used together with SMT, or with Through Hole Solder
connectors that are not locked down with hardware.
Holtite®
Placement
Through Hole
Solder
Component
Insertion
Holtite® placement equipment places and presses Holtite® sockets into the PCB. This
step would need to be the first process step in board assembly.
Plated thru-hole components are pre-formed and pre-cut, and inserted by hand into the
Holtite® sockets.
Then to Press
fit - see above
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2.3
Design For Manufacturability Guideline
TB-2083
Manufacturing Process Flow - Cost Drivers
Shown below is a breakdown of AMPHENOL TCS's process flow with indications of the associated cost drivers and
the recommended alternatives that would minimize cost. The lowest cost, highest quality, preferred manufacturing
processes are shown as a solid line. Additional, less preferred, manufacturing processes, i.e. 2-sided SMT, Through
Hole Solder, 2-sided Press fit and manual intensive Threaded Assembly, are shown by a dotted line.
Cost Drivers
Alternatives
Setup
• Number of part types
• Number of new parts
• Board size and shape
• Minimize component values
• Use existing part numbers
• Panelize and add tabs
SMT
• PCB size, shape and edge clearance
• Non std. Parts and packaging
• Panelize and add tabs
• Industry std. parts and packaging
• Additional setups (Tools/programs)
• Longer setup and run times
• Increased cycle time
• Place components on one side
•
•
•
•
•
•
•
•
•
•
2nd Pass
SMT
Through
Hole Solder
Press-fit
2nd Pass
Press-fit
Threaded
Assembly
Manual place parts
Selective solder fixtures
Wave solder increases DPMO
Lead length and protrusion
Greater PCB Thickness'
Use Press fit/SMT
Use Press-fit or single sided SMT
Use SMT or Press-fit
Match component to PCB thickness
Holtite® process
• PCB size, shape and edge clear
• Component pre-load capability
• Panelize and add tabs
• Component lead design allows pre-load
• Additional setups (Tools/programs)
• Longer setup and run times
• Increased cycle time
• Place components on one side
• Number of parts
• Manual Process
• Number of screw and thread sizes
• Use Sems hardware, minimize hardware
• Minimize the use
• Standardize thread sizes and use pressfit hardware to minimize screws
• Use captive press-fit studs or
• Leave open to allow fixturing
• 2-sided assembly
• Buried hardware
Test
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2.3.1 Surface Mount Process Flow
The flow chart below demonstrates the basic process flow for assembly of surface mount components. The solid
lines represent the primary or lowest cost process. The issues below highlight major design features that will impact
manufacturing cost, yield and cycle time. Shaded areas represent areas of concern.
Setup
$
Set-up cost is driven by the number of part types and any
special requirements - such as Dry-pack. Parts must be
specified on Tape & Reel or Matrix trays.
Yield
Cycle
Time
Cycle time is driven by the number of parts in the setup.
$
Print
Yield
Yield factors impacting process include PCB flatness,
soldermask, surface finish, component lead pitch and
fiducial recognition.
Cycle
Time
$
Auto Place
Yield
Cycle
Time
Second
Side
Yield factors include the part size, weight and shape and
component lead type/condition.
Cycle time increase with number of components placed
$
Reflow
Yield
The reflow process yield is affected by PCB size and
thickness, copper weight and distribution, component lead
type and condition.
Cycle
Time
Aqueous
Wash
$
Yield
Cycle
Time
Cost and cycle time is increased when aqueous compatible
components are not used. Aqueous incompatible parts
require manual processing.
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2.3.2
Design For Manufacturability Guideline
TB-2083
Press Fit Process Flow
The flow chart below demonstrates the basic process flow for assembly of press-fit components. The solid lines
represent the preferred or lowest cost process. The issues below highlight major design features that will impact
manufacturing cost, yield and cycle time. Shaded areas represent areas of concern.
Setup
Pre-load
Second
Side
Auto Press
$
Set-up cost is driven by the number of part types and any
special requirements.
Yield
Cycle
Time
Cycle time is driven by the number of parts in the setup.
$
Yield
Cycle
Time
$
Yield
Cycle
Time
Cost, cycle time and yield increase when components do
not have lead-in capability and require being moved to a
manual process
Cost increases with deviations to board size, shape and
edge clearance
Yield factors include a proper lead to hole ratio.
Cycle time increases with number of components placed
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3.0
Design For Manufacturability Guideline
TB-2083
PCB Mechanical Requirements
All parts of Section 3 apply to DFM recommendations that are applicable within each respective
process. This does not apply to interactions between different processes.
This section covers assembly processing requirements and limitations to be considered when determining the
physical dimensions for new printed circuit boards.
Process handling costs during assembly are determined by three major factors:
• Board Dimensions
• Tooling Hole Placement
• Edge Clearances
The following processing formats are described in this section:
• SMT
• Through Hole Solder
• Automated Press fit assembly
• Semi-Automated Press fit.
• Holtite® Assembly
Note: If design includes multiple processes, follow guidelines of the most restrictive process.
The preferred process is Press Fit assembly. When the backplane design requires discreet and logic devices - SMT is
the preferred process. The Through Hole Solder process is not preferred, but acceptable.
Printed circuit boards that do not meet the requirements described in this section cannot be processed using
automated assembly equipment. There are preferred alternatives to each specific deviation - Consult with Factory
for more information.
DFM Benefit
Use of the limits defined in this section will insure that new PCB designs can be manufactured using industry
standard automation equipment, which results in higher product yields and reduced cycle time.
DFM Impact
* Consult with Factory for alternatives
Requirement Deviation
PCB Shape
PCB Size and Edge clearance
PCB Thickness
Tooling Holes
Fiducials
Impact
Requires PCB panelization and breakaway tabs or
Special fixturing and/or manual assembly
Special fixturing and/or manual assembly
Poor solder yields due to high PCB thermal mass
Special fixturing and/or manual assembly
Reduced component placement accuracy
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way not previously approved by Amphenol TCS Division
Release Date:
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"C"
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Amphenol TCS
3.1
Design For Manufacturability Guideline
TB-2083
PCB Preferred Shape
AMPHENOL TCS Automated Assembly Equipment requires that the printed circuit board have two parallel
sides, denoted in the diagrams below as bold lines, with chamfers on all 4 corners. The two parallel edges, will run
on conveyors, transferring the PCB in and out of machines. These transfer edges are usually referred to as the Length
(L dimension). (Note: Throughout this document, L is assumed to be the dimension given to the side that runs on the
conveyor.) The dimension, which spans the conveyor, is the Width (W). It is preferred to have L greater than W.
If the PCB does not follow the requirements defined below, see section 3.1.1 for minimum acceptable shapes.
(PCB edge that runs on conveyor is denoted with a bold line
)
L
W
Chamfer 1/16" x 45°
Parallel Sides
(Running on conveyors)
Direction of Travel
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
3.1.1
Design For Manufacturability Guideline
PCB Acceptable Shape
The following is a general guideline for minimum shape requirements.
(PCB edge that runs on conveyor is denoted with a bold line
•
•
•
•
•
•
•
TB-2083
)
Leading and trailing edges on each side are 4.5" minimum
Each notch length "X" < 4"
Each distance of PCB that runs on conveyor "Y" > 4.5"
The total sum of edge that will run on the conveyor > 80% of the PCB Length (L)
All outside corners should have a chamfer - to prevent conveyor jams and operator injury.
The depth of the notch(s) does not reduce the width by more than 50% (W1 > 1/2W)
The Length must always be > 50% of the Width, or the side of the board that runs on the conveyor, must
always be > 50% of the side that spans the conveyor - See next page.
If the PCB shape does not meet these requirements, Consult with Factory on other alternatives. See Section 3.1.2
for examples of unacceptable PCB shapes.
L
X
Leading Edges
W1
Trailing
Edges
W
Y
Parallel Sides
(Running on conveyors)
Chamfer 1/16" x 45° on all
outside corners
Direction of Travel
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
3.1.2
Design For Manufacturability Guideline
TB-2083
Minimum Acceptable Length to Width Ratio
SMT and Through Hole Solder Process - Length is > 75% of the Width
Example of minimum acceptable:
L = 15"
W = 20"
Parallel Sides
(Running on conveyors)
Direction of Travel
Press Fit - The Length is > 50% of the Width
Example of minimum acceptable:
L = 10"
Parallel Sides
(Running on conveyors)
W = 20"
Direction of Travel
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way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
Page:
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Amphenol TCS
Design For Manufacturability Guideline
TB-2083
3.1.3 PCB - Non Preferred Shapes
The following illustrates examples of Non Preferred PCB shapes: (Unacceptable for automation/conveyorization)
Total conveyor edge < 80% of total PCB length
No Chamfers
Notch length > 4"
PCB Edge that runs on
conveyor < 4-1/2"
Leading/Trailing edge
is missing or < 4-1/2"
Direction of Travel
Do not have 2 parallel edges
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way not previously approved by Amphenol TCS Division
Release Date:
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"C"
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Amphenol TCS
3.2
Design For Manufacturability Guideline
TB-2083
PCB Size and Edge Clearance
All dimensions
in inches - unless
noted
PCB
Min Size
(W,L,T)
Max Size
(W,L,T)
Component
Edge Clearance
(E)
SMT
Through
Hole Solder
Automated
Press-Fit
SemiAutomated
Press-Fit
Automated
Holtite®
4x4x.070
4x4x.070
7.5x7.5x.100
No Restriction
7.5 x 7.5 x .070
36 x 48 x .450
.220*
(* See Section
3.2.2)
24x36x.400
22.5x36x.200
36x48x.450
36x*Note*x
(.750 minus the
max connector
height)
.125
.125
.220*
(*See Section
3.2.1)
.125
*Note: 39" long PCB's, or less, are standard for the semi-automated presses, but these machines are not
restricted to that length - having capabilities that exceed 39" - Consult with Factory - (special processing
may be required)
E
No Components - Keep out area
E
No Components
Keep Out Area
W
E
E
L
Direction of Travel
T
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
3.2.1
Design For Manufacturability Guideline
TB-2083
Automated Press-Fit Detailed Placement Envelope
The edge clearance dimension given in section 3.2 is worst case. The Automated press-fit process requires .150"
edge clearance on a single sided PCB, but depending on component height, requires up to .220" edge clearance on
the first pressed side of a 2-sided assembly. Below, is an illustration that shows the edge clearance on the bottom
side.
No Components - Keep out area
Component height < .100
Component height < .200
Component height < 1.06"
0.150"
0.192"
A
0.220"
A
Direction of Travel
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way not previously approved by Amphenol TCS Division
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"C"
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Amphenol TCS
3.2.1
Design For Manufacturability Guideline
TB-2083
Automated Press-Fit Detailed Placement Envelope (cont'd)
Below is View A-A from the previous page, which shows the end view, illustrating the top and bottom placement
envelope with edge clearances.
Edge Clearance
Top Side
All components up to 1.65"
(Measured from bottom of PCB)
.150"
Bottom side
If component height is < .100
If component height is between .101" and .200"
If component height is between .201" and 1.06"
.150"
.192"
.220"
.150" Min
1.65" Max
Top Side Max
Placement Envelop
Bottom Side Max
Placement Envelop
.150" Min
PCB Bottom
Surface Plane
.100"
Max .200"
Max
1.060" Max
.192"
Min
.220"
Min
PCB Cross Section
Placement Area Envelop
View A-A From Previous Page
PCB Direction of Travel =
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way not previously approved by Amphenol TCS Division
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"C"
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Amphenol TCS
3.2.2
Design For Manufacturability Guideline
TB-2083
Automated Holtite Detailed Placement Envelope
The edge clearance dimension given in section 3.2 is worst case. The Automated press-fit process requires .150"
No Components - Keep out area
edge clearance on a single sided PCB, but depending on component height, requires up to .220" edge clearance on
the first pressed side of a 2-sided assembly. Below, is an illustration that shows the edge clearance on the bottom
side.
Component height < .300”
Component height < .400"
0.150"
A
0.220"
A
Direction of Travel
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way not previously approved by Amphenol TCS Division
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"C"
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Amphenol TCS
3.2.3
Design For Manufacturability Guideline
TB-2083
Holtite Insertion Location Limitations
These Holtite insertion limitations in the picture below are determined by the mechanical design and limitations of the
automated Holtite Insertion Machine. These are the Holtite insertion limitations even for a board with no other components on
it.
No Holtites can be inserted in this area
0.270
0.070
0.070
Direction of Travel
0.270
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
3.3
Design For Manufacturability Guideline
TB-2083
Tooling Hole Requirements
SMT
Through
Hole Solder
Automated
Press-Fit
Semi
Automated
Press-Fit
Automated
Holtite®
Qty:
3
None
2
3
2
Type:
Non-Plated
Thru-Hole
N/A
All dimensions
in inches - unless
noted
Tooling Holes:
Size:
Location:
(*Asymmetrical)
Non-Plated Thru-Hole
Standardize on a .125" hole with a .250 Dia. Keep-out circle
Corners
#'s 1,2,3
Corners
#'s 1 & 2
or #2 & 3
N/A
Corners
#'s 1,2,3
Corners
#'s 1 & 2
or #2 & 3
*Note: Tooling holes should have an asymmetrical pattern to prevent reverse loading on automation equipment (Poka-Yoke)
No Components - Keep out area
No Components
Keep Out Area
#1
.250″ clearance around tooling
holes
Example: Hole #3 makes
the pattern asymmetrical
with a rectangular board
#2
#3
.250" Min
.250" Min
Direction of Travel
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
3.4
Design For Manufacturability Guideline
TB-2083
Fiducial Mark Requirements
For each side of the PCB which has SMT devices, the PCB design must provide three board level (global)
fiducial marks. When fine pitch components are used, there must be two local fiducials located on opposite
corners of the fine pitch land pattern. These marks are needed for automatic alignment of the board and
components during the SMT assembly process. A 0.040″ diameter solid circle inside of an 0.080″ diameter
soldermask clearance window is preferred for both local and global fiducial marks.
Requirements
DFM Impact/Benefit
• Fiducials should be clear of soldermask, silkscreen,
and etch.
• Insures the clarity of the fiducial target for vision systems
• They should be placed as far apart as possible, but
within the component placeable area. (They cannot
infringe into keep-out zones - such as edge
clearance and tooling hole keep-outs)
• Maximizes component placement accuracy
• Secondary side fiducials should be placed in the
same corners as the primary side, so they appear
in different locations when the board is flipped.
• Prevents machine automated assembly if PCB is accidentally
run upside down. (If machine can't find fiducials - it will stop
the process)
Circular Fiducial Mark
Soldermask
Clearance area
.080"
.040"
Fiducial Solder Pad
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Amphenol TCS
3.4.1
Design For Manufacturability Guideline
TB-2083
Global and Local Fiducial Requirements - SMT Only
Global
Qty:
Size:
Location:
3
.040" dia. Pad with an .080"
solder mask clearance.
PCB corners, located
asymmetrically, inside the
component placeable area
Local
2 per component with
lead pitch < 25 mils
.040" dia. Pad with an .080"
solder mask clearance.
Diagonally - outside component
outline
Solder Mask Clearance
No Components - Keep out area
Global Fiducials
(Asymmetrical)
Component placeable area
Fine Pitch
Component
Local Fiducials
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Amphenol TCS
Design For Manufacturability Guideline
TB-2083
4.0 Component Guideline
This section covers assembly processing requirements and limitations to be considered when selecting components including package standards, sizes, styles, materials, lead finishes, markings, and overall process compatibility.
Amphenol TCS uses the following industry standards for information on components and component packaging:
1. JEDEC (http://www.jedec.org/)
4.1
2. IPC
(http://www.ipc.org/)
3. EIA
( http://www.eia.org/ )
Component, Package and Source Standards
Requirements
DFM Impact/Benefit
• Select parts that are already in use at AMPHENOL
TCS
• The use of existing parts helps to control manufacturing costs
and part number proliferation in stock rooms.
• Use industry standard parts.
• When the backplane design requires discreet
and/or logic devices - use SMT components.
• Industry standards insure that parts from multiple sources
will conform to established mechanical specifications.
• Provides a gas-tight connection, minimizing long-term
corrosion related failure opportunities
• Assembly, with no heat cycling or thermal strain to board.
• SMT processes provide better yields and lower cycle times
than Through Hole Solder, when solder processing is required.
• Standardize component land patterns for
components that have the same package.
• Minimizes automation equipment programming time, and
reduces the opportunity for new problems (minimize DPMO)
• Use Press-fit components
i.e.: All 0603 SMT components should use ONE
Land Pattern
• If a new part is required, select a package type that
has an existing Land Pattern
• For new land patterns - refer to vendor
recommended footprint or IPC standards.
• Use the IPC-SM-782 Land Pattern Calculator.
• Avoid single source vendors
• Insures that a device will be available to meet production
ramps.
• Components that differ in form, fit and function
requirements must be identified by different part
numbers.
• Eliminates the risk of mechanical interference's or functional
changes in product.
(http://www.ipc.org/html/fsresources.htm)
i.e.: An 0603 and 0805 having the same electrical
function, do not have the same form/fit, therefore
must be different part numbers
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
4.2
Design For Manufacturability Guideline
TB-2083
SMT & Through Hole Solder Component Sizes and Lead Pitches
All dimensions in
inches - unless
noted
Through Hole
Solder*
SMT
Body Size Min (L,W,H)
0402
No Restriction
Body Size Max (L,W,H)
L = 2.2"
W = 2.2 "
H = 0.60"
L = No Restriction
W = No Restriction
H = 1.5"
20 mil
.100
Min Lead Pitch
* Through Hole Solder lead lengths defined in Section 5
4.2.1
SMT Component - Auto Placement Compatibility
Requirements
DFM Impact/Benefit
• All parts should have top surface that is smooth and flat
- conducive to vacuum pick-up. Minimum area is
dependent on component weight.
• Large connectors should have a minimum .200" diameter.
• SMT parts that require any amount of insertion force,
are not preferred - Consult with Factory
• Over-all part dimensions must be uniform and
repeatable.
• Parts would need to be placed Manually - increasing
cost and cycle time, decreasing quality.
• Dimensional variations in packages will cause
placement variations - resulting in reduced quality,
increased rework.
• Component carrier specification - see Section 4.8.
4.2.2
SMT Components - Preferred
Component
Size, lead pitch, type
DFM Benefit
Chip (Caps, Res's, diodes)
0805 + 1206
• Most robust packages - improving process yields
Transistors
SOT23
SOIC's
Gullwing < 20 pin = 50 mil pitch
• Limiting package types will help optimize
throughput and improve yields
Diodes
Avoid Melf packages
ASIC's
QFP < 208 pins, 20 mil lead pitch
min
• Reduces programming time, and simplifies oven
profiling and rework
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
4.2.3
Design For Manufacturability Guideline
SMT Components - Acceptable
Component
Size, lead pitch, type
Chip (Caps, Res's, diodes)
0402 + Larger
Transistors
SOT23 + Larger
SOIC's
Gullwing = 50 mil pitch
Diodes, Leds, Crystals
All - molded, sealed - no Melf
packages
PLCC's
All
Less than 20 pin connectors
Consult with Factory
ASIC's
QFP - 20 mil lead pitch min
4.2.4
TB-2083
DFM Benefit
• All of these packages work well, but increase the
number of active packages/components in
inventory. This increases material overhead costs
associated with stocking, handling and machine
set-ups.
• Standardization using common/preferred packages
reduces inventory costs
SMT Components - Non-Preferred
Component
DFM Impact
Alternate
ASIC's < 20 mil pitch
Difficult Screen Print process - poor solder
yields
• Consult with Factory - possible BGA
alternative
Cylindrical Parts (Melfs)
Placement & solder defects
• Change to 0603 & 0805 package.
Non-Hermetically sealed parts
Trapped water during cleaning process
• Use molded sealed packages
Non-Symmetrical parts
Large connectors:
- With mechanical hardware
- Without hardware
Vision Centering variations
• Use symmetrical parts
• Use Press-fit connectors
4.2.5
Requires manual assembly - poor yields
Stress/Cracked solder joints and lifted pads
Through Hole Solder Components - Not a Preferred Process, but acceptable
Component
DFM Impact
Alternate
Preferred
Ensures maximum solderability.
• Connectors and power modules change
to Press-fit
• Discreet and logic devices - SMT
Non-Hermetically sealed parts
Trapped water during cleaning process
• Use molded sealed packages
Components without solder
side lead protrusion
Causes solder voids and poor solder joints,
resulting in long term failures.
• Use SMT or Press fit components.
(Holtite® is a possible alternative - see
section 2.2.1 and Consult with Factory.)
Specify component lead
length's that allow a .020"
minimum tail protrusion.
Non-Preferred
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"C"
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Amphenol TCS
4.3
Design For Manufacturability Guideline
TB-2083
Press-Fit Component Sizes and Machine Insertion Forces
Semi Automated
Press-Fit
Automated
Holtite®
Height*
No size restriction @ min insertion:
500 lbs.
6" Long x .75" Wide x
(Max Height = .75" minus PCB thickness)
Standard Holtite®
P/N 8134-HC-5P3
Standard Holtite®
P/N 8134-HC-5P3
Min: 10 lbs.
Max: 11 tons
Min: 500 lbs.
Max: 6900 lbs.
See Vendor Spec
Automated
Press-Fit
Min (L,W,H)
No min size restrictions
6" Long x 1.25" Wide x
Max (L,W,H)
Min/Max Insertion
Force
*Note: For max component height, see section 3.2.1
4.3.1 Press-Fit Pin and Component Requirements
The critical part of the press-fit design, is the "compliant" section of the pin. The compliant section is designed, so
that an elastic deformation of the pin takes place during insertion, therefore exerting a constant force against the hole.
The compliant section is compressed, and conforms to the hole allowing for a gas-tight connection. This ensures
long term electro-mechanical reliability of the interconnection. The compliant pin also reduces strain on the board.
With a rigid or solid pin, there is no compliant section, and the elastic deformation occurs entirely in the board,
which results in damage of the plated-through holes. It is preferred to stay away from press-fit designs that have no
compliant section, and essentially take a square pin and force it into a round hole.
Requirements
DFM Impact/Benefit
• "Eye of the needle" style compliant pin is one of the
preferred press fit designs, where the pin conforms
to the hole.
• Creates a gas-tight seal, that is not susceptible to
corrosion, providing a long term, robust, electromechanical connection.
• Pin lead-in beyond the "Eye" - Minimum length
required for pre-load
• Allows for component pre-load and stable transfer into
automated press, without having the component fall or
lean out of position.
• Pin design incorporates a shoulder, or some positive
mechanical mating of the seating tool to the pin,
providing uniform pin seating.
• Prevents overstress on the plastic mold and incorrect pin
seating, resulting in a poor mating connection.
Preferred Pin Design
Pin Shoulder
Eye of the Needle - This is the compliant section,
where the pin displaces the
plating, and complies with the
hole
Pin Lead-in
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way not previously approved by Amphenol TCS Division
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"C"
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Amphenol TCS
4.3.2
Design For Manufacturability Guideline
TB-2083
Press-Fit Components - Preferred Pin Design
Pin
DFM Benefit
• Compliant section "gives" during insertion and provides a constant
outward force on the hole barrel, after insertion, providing pin
retention.
• Shoulder provides positive seating with tooling
• Robust electro-mechanical connection, with pin "lead-in" for
automation.
• Provides a gas-tight seal without hole damage
• "Eye of the needle" style
Preferred Pin Design
Pin
Hole
Constant outward
force against hole
side-wall
A
A
Eye of the Needle
Section A-A
Cross-section of "Eye of
the Needle" in the plated
through-hole.
Note: This is one example of what makes a good press-fit pin design. It
illustrates what to look for when selecting press-fit connectors
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way not previously approved by Amphenol TCS Division
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"C"
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Amphenol TCS
4.3.3
Design For Manufacturability Guideline
TB-2083
Press-Fit Components - Preferred Design
Component
DFM Benefit
Component design allows tooling to contact the
pin AND plastic housing at the same time,
without coming in contact with mating surfaces
• Press tooling does not contact the pins, at a location, where
electrical contact is made with mating connector, but can provide
accurate pin seating.
Component design allows tooling to be generic one tool for multiple pin heights
• Minimize tool changes - reducing cycle times on automated
equipment.
When using "Long Tail" components for CenterPlane assembly, it is preferred to specify Mylar
fan strips on the connector pins - if the connector
vendor offers it as an option.
• Keeps the long pins straight for ease of pre-load.
Preferred Connector
Design
Connector Housing
Seating Tool
One tool can be used to
press many flavors of
connectors, regardless of
pin height
Area where
electrical contact
is made with
mating connector
Allows tool, to use pin, to seat
the connector, and not
overstress the housing
PCB
Shoulder provides
accurate seating,
resulting in a consistent
wipe for mating
connector and pins
Note:
• Tooling design is a function of manufacturing, but the connector design has a definite
impact on the ability to design the best tooling.
• This is one example of what makes a good press-fit connector design - to illustrate what
to look for, and how the tooling best interfaces with the connectors
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way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
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Amphenol TCS
4.3.4
Design For Manufacturability Guideline
TB-2083
Press-Fit Components - Acceptable
Component
DFM Impact
Cross Section # 1
Doesn't comply as well rigid compliant section.
Cross Section # 2
Compliance is a little weaker
Cross Section # 3
Rigid compliant section
Alternate
• All of these packages work well, but are more sensitive
to hole size tolerances, plating thickness tolerance and
hole solder sag and "dog-boning".
Compliant section
is rigid, and can
cause some hole
deformation - but
acceptable
Plated Through Hole
Cross Section #1 - Pin in a
Plated Through-Hole
Pin
Hole
Cross Section #2
Pin complies to the plated hole but retentive forces are minimal but acceptable
Cross Section #3
This pin design is also
rigid - but acceptable
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way not previously approved by Amphenol TCS Division
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"C"
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Amphenol TCS
4.3.5
Design For Manufacturability Guideline
TB-2083
Press-Fit Components - Non-Preferred
Component
DFM Impact
Alternate
2-Piece connectors
Requires a 2-step press operation
• Change to one piece
Solid Pin with no compliant
section - See Fig 1
High insertion forces, PCB hole damage.
• Add compliant section or
change vendors.
No pin "lead-in" - See Fig 2
Connectors cannot be pre-loaded for automated press
and would require manual processing, but would still
be susceptible to pin "folding" and hole damage.
• Use components with "lead-in"
style pins.
Eye of the needle with poor
compliance design - See Fig 3
Does not provide gas-tight seal and good mechanical
grip
• Improve compliant design or
change vendors
Non-Preferred
Pin Designs
PIN
Plated Thru Hole
Solid Pin - no
compliance - causes a
large amount of hole
deformation - resulting
in PCB damage and
possible long-term
failures
Fig 1
Cross Section - Solid Pin in a
Plated Thru-Hole
Eye is too long
- compliant
section of pin is
weak and may
collapse
No pin
"lead-in"
Fig 2
Fig 3
Non-Preferred Pin
& Housing Design
Inconsistent pin seating
Shoulder not designed into
pin - tooling will press using
plastic, and pins will slip…
This document contains proprietary information that is not to be used in any
way not previously approved by Amphenol TCS Division
…Or, flat rock tooling is
required, and pins are
unsupported, and may bend.
Release Date:
6-16-04
Rev:
"C"
Page:
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Amphenol TCS
4.4
Design For Manufacturability Guideline
TB-2083
Threaded Assembly Process Requirements
Requirements
DFM Impact/Benefit
• For power connections, it is preferred to use "Sems"
style steel nuts. Phosphor bronze studs with electrotin plating are acceptable.
• Minimizes required tooling - minimizing handling time.
• All hardware locations areas should be accessible
with torque tools.
• Minimizes handling time.
• Bus bars, stiffeners and other mechanical pieces
should be mechanically fastened. Epoxies are not
recommended.
• Application of epoxy is manual and operator dependent,
high DPMO rates.
• Epoxy or powder coated busbars are preferred,
when insulation is required between the busbar and
other components - including the PCB.
• More consistent and accurate process, reducing the
possibility of shorts to the busbar.
•
The use of kapton tape to insulate bus bars is not
recommended.
• Kapton tape is manually cut and fitted - prone to manual
process errors.
• For hardware stack-ups, the use of captive (press
fit) studs and nuts are preferred
• Minimizes required tooling - minimizing handling time.
• "SEMS" style hardware is preferred.
• Minimizes required tooling - minimizing handling time.
4.4.1
Threaded Assembly Components
Component
Size, lead pitch, type
DFM Benefit
Preferred
Screw Head Style
"Sems Style" Pan Head
Driver Style
"Phillips", "Torx" or "PosiDrive"
Nuts
"Sems"
Standard Threads
#4-40, 6-32, 8-32, 10-32,
1/4-20, 5/16-18
• Minimizes part numbers and tooling requirements
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way not previously approved by Amphenol TCS Division
Release Date:
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"C"
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Amphenol TCS
4.5
Design For Manufacturability Guideline
TB-2083
Component Lead Plating
Requirements
• Tin-Lead (Sn/Pb) plating is preferred for the solder
process.
• Gold Leads are not preferred in the SMT process if used - should be "Gold Flash" < 200 microns.
• SMT parts only available in gold with thickness >
200 microns, would require pre-tinning before
coming to AMPHENOL TCS
• Gold Leads are limited to the Thru-hole wave solder
process Consult with Factory
• Devices which mate should have matching finishes,
in the mating contact area.
• Other lead finishes - Consult with Factory.
DFM Impact/Benefit
• Provides stable solderable finish
• Tin-Lead generally has a 6-month solderability shelf life
• Finish is best suited to AMPHENOL TCS assembly
process - see Section 2
• Solder joints with more than 2.5% gold by volume, will
result in an embrittled solder joint, which is a reliability
issue
• Added cost and cycle time.
• Wave soldering process will remove gold from the lead,
and the gold will mix in the molten solder pot.
• Metal mismatch causes reliability issues due to long term
degradation of the connection from galvanic corrosion
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
4.6
Design For Manufacturability Guideline
TB-2083
Orientation Marking
Requirements
DFM Impact/Benefit
• All components must have appropriate indicators for
pin 1, +, -, cathode, anode or other orientation marks
clearly identified.
• Component orientation can be done with an
asymmetrical pin layout that allows only one
orientation. (Poka-Yoke) See connector at bottom.
• Orientation marks allow for inspection of parts after
placement.
• Necessary to assure correct placement at manual assembly
and rework.
Examples:
Asymmetrical - cannot be
assembled in reverse
Pin 1 Marking
1
VHDM Connector
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Amphenol TCS
4.7
Design For Manufacturability Guideline
TB-2083
Assembly Process Compatibility
Requirements
DFM Impact/Benefit
• All parts must be compatible with the process that
they will be subjected to, as described in the table
below.
Note: All of the restrictions in this section do not affect
and are not applicable to Press-fit components, which
minimizes defect opportunities in the Press-fit process.
• Parts that are damaged in the assembly process will
require rework, scrap, or worse - the damage may not be
immediately detected and could result in long-term field
failures.
• Parts would require manual handling/assembly to avoid
the incompatible process step
The following table defines what process each component type must withstand:
Process Type
Component Type
4.7.1
Moisture
Sensitivity
Water
Wash
Wave
Solder
Reflow
Solder
SMT
Through
Hole
Solder
PressFit
Holtite®
√
√
N/A
N/A
√
√
N/A
N/A
√
√
√
Not
Compatible
Not
Compatible
Not
Compatible
Not
Compatible
Not
Compatible
Moisture Sensitivity
Requirements
• All semiconductors and plastic encapsulated
components must be compatible with requirements
defined in JEDEC Standard J-STD-020A*.
http://www.jedec.org/download/default_joint.cfm
DFM Impact/Benefit
• This requirement insures that parts are not damaged from
the “pop-corning” and die de-lamination effects which
are often caused by the entrapment of moisture in
component packaging materials.
* J-STD-020A Moisture/Reflow Sensitivity Classification
• Parts that are rated a level 3 or 4 must be flagged and
specified for DRY-PACK HANDLING.
• Increased handling/packaging costs associated with
DRY-PACK packaging
• Parts that are rated level 5 or higher are not
acceptable.
• Would require special processing cycles
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Amphenol TCS
4.7.2
Design For Manufacturability Guideline
TB-2083
Water Wash Compatibility
Requirements
DFM Impact/Benefit
• All components should be compatible to a water
wash - cases are sealed to prevent water infiltration.
• Contaminants can be entrapped within the case, causing
short and long-term component failures.
• Parameters:
70 PSI - Spray pressure
Water - 4 Minute Duration @ 160º F (71º C)
Air - 4 Minute Drying @ 160º F (71º C)
• Through Hole Solder components should allow a
minimum of .003" standoff, to allow cleaning
beneath the component
• Contaminants can be trapped between the component
body and the PCB, and will erode the solder joint and
component lead, causing long term failures
• Components should have no features that entrap
water between the component and the PCB.
Part body sits flat down on
the board, which traps flux
between PCB and body.
Component foot to
allow cleaning under
the component body
PCB
4.7.3
Wave Solder Exposure Conditions
Requirements
• All SMT and Through Hole Solder components
should be compatible with the following conditions:
230º F (110º C) for 4 minutes, with a peak of 302º F
(150º C) for 20 seconds
4.7.4
DFM Impact/Benefit
• Parts that do not meet this requirement can be damaged in
the wave solder process. Therefore, hand soldering is
required - which increases cost, cycle time and reduces
quality.
Reflow Solder Exposure Conditions
Requirements
• All SMT parts should be capable of withstanding
the reflow profile as described by JEDEC Standard
J-STD-020A.
http://www.jedec.org/download/default_joint.cfm
DFM Impact/Benefit
• Parts that do not meet this requirement can be damaged in
the reflow solder process. Therefore, manual placement
and hand soldering is required - which increases cost,
cycle time and reduces quality.
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
4.8
Design For Manufacturability Guideline
TB-2083
Component Carrier Specifications
Amphenol TCS Connection Systems references the following component carrier package
specifications:
1.
2.
3.
4.
5.
6.
7.
4.8.1
IPC Specifications
Manufacturers recommended package specifications
JEDEC Publication 95
EIA Standard 481-1
EIA Standard 481-2
EIA Standard 481-3
EIA Standard for 0402 Components
Material Specifications for Carrier tape and Cover tape
Below is a listing of material* - in order by preference:
1.
2.
3.
4.
Plastic carrier with pressure sensitive adhesive on plastic cover tape
Paper carrier with pressure sensitive adhesive on plastic cover tape
Matrix Tray
Plastic Tubes
* All material must be Static Safe - identified with any of the following terms: Antistatic, Static
Dissipative, or Conductive
4.8.2
Label Requirements
The following is the minimum information required on both reels and packaging
Note: Labeling of packages or bags is required if the label on the reel is not visible.
1.
2.
3.
4.
5.
Name of Manufacturer
Manufacturer Part Number
Quantity of Components on Reel
Value of Reeled Component including tolerance
Date Code label
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way not previously approved by Amphenol TCS Division
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Amphenol TCS
Design For Manufacturability Guideline
TB-2083
5.0 PCB Layout (Placement and Spacing) Requirements.
All parts of Section 5 apply to DFM recommendations that are applicable with the interactions
between multiple processes.
This section covers assembly processing requirements and limitations to be considered when placing components on
the Printed Circuit Board. The primary cost factors are:
•
•
•
Component placement and distribution
Spacing and keep-outs
Hole and pad design
Note: For SMT land pattern requirements, refer to Section 4.
Processing formats described in this section:
• SMT
• Through Hole Solder
• Press Fit Assembly
• Holtite Assembly
Top and Bottom Definition
The terms "Top Side" and "Bottom Side", (sometimes referred to as "Primary" and "Secondary"), are used in this
section of requirements. The diagram below provides a very general description of how to distinguish top from
bottom, within a given process, and establish a standard convention for terminology:
Top Side
PCB
Usually the side that is/has:
• Greater # of components
• Larger (heavier) components
• Less design restrictions
• Assembled after Bottom side
Usually the side that is/has:
• Fewer components
• Smaller components
• More design restrictions, such as greater edge clearance, spacing and thermal
requirements.
• Assembled First
• Runs through molten solder, when there are Through Hole Solder components
Bottom Side
Note: Top side SMT may not be the same as top side Press fit - i.e.: if a board has SMT on one side and Press fit on
the other, the SMT side would be considered the Top side within the SMT process, but in the Press fit process the
SMT parts would be on the bottom side and the Press fit parts would be on the top - see next page.
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Amphenol TCS
Design For Manufacturability Guideline
TB-2083
SMT Assembly
Top Side
SMT parts are assembled on Top Side
Bottom Side
PCB is flipped to go through Press fit Assembly
Press Fit Assembly
Top Side
Press Fit parts are assembled on Top Side…
…while, the SMT parts are now considered to be on the bottom side of the Press fit process - therefore the SMT
parts must meet the requirements, such as edge clearance, of the Press fit bottom side assembly process.
Bottom Side
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Amphenol TCS
5.1.0
Design For Manufacturability Guideline
TB-2083
Top and Bottom Side Placement and Distribution - SMT & Through Hole Solder
Requirements
DFM Impact/Benefit
• All SMT parts specified in Section 4.0 can be
placed on Top side
• SMT chip components or SO16 and smaller are
allowed on bottom side.
• Single sided assembly is preferred
• Parts that are larger (heavier) will fall off during the second
reflow, and would therefore require adhesive attachment.
* If greater than SO16 - Consult with Factory
• When Through Hole Solder is required - SMT
components must be < 0.150" in height for
bottomside assembly.
• 0.150" is the maximum allowable height for wave solder
masking
• "J" leaded devices, such as PLCC's and SOJ's are
prohibited from the bottomside.
• These packages are difficult to secure with adhesive.
• Through Hole Solder parts can only be placed on
Topside - they should not be placed on Bottomside.
• Through Hole Solder parts place on bottomside would
require a secondary assembly operation and hand soldering.
• Through Hole Solder parts must have a lead
protrusion of .020" min/.100" max. (Select
components with lead length's that exceed the
PCB thickness by .020" - .100".)
• Lead protrusion < .020" - Solder will not "wick" up the
hole, without the lead protrusion, causing solder voids and
poor solder joints, resulting in long term failures.
• Lead protrusion > .100" - Leads would need trimming to
prevent bent leads during handling, resulting in shorts
Top Side
1.5" Maximum
Through Hole Solder
components - topside only
"J" leaded and larger
(heavier) devices topside only
Chip and smaller SMT
devices - top and bottom
side
< 0.150"
0.020" Minimum
0.100" Maximum
Bottom Side
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Amphenol TCS
5.1.1
Design For Manufacturability Guideline
TB-2083
Top and Bottom Side Placement – Automated Press Fit
Requirements
DFM Impact/Benefit
• All Press Fit parts specified in Section 4.0 can be
placed on top and bottom side
• The only top and bottom restriction, for Press fit
assembly, is the placement envelope. You must
keep all of the components in the shaded area, or
there will be machine/conveyor interferences. Refer
to view A-A in Section 3.2.1.
• Maximum use of PCB real estate - however, single sided
assembly is preferred.
• Press-fit connectors placed outside this envelope will
require manual assembly and can only be assembled after
this process.
.150" Min
1.65" Max
Top Side Max
Placement Envelop
Bottom Side Max
Placement Envelop
.150" Min
PCB Bottom
Surface Plane
.100"
Max .200"
Max
1.060" Max
.192"
Min
.220"
Min
PCB Cross Section
Placement Area Envelop
View A-A From Previous Page
PCB Direction of Travel =
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Amphenol TCS
5.1.2
Design For Manufacturability Guideline
TB-2083
Top and Bottom Side Placement - Holtite
Requirements
DFM Impact/Benefit
• All Holtite parts specified in Section 43 can be
placed on top and bottom side
• The only top and bottom restriction, for Holtite
assembly, is the placement envelope. You must
keep all of the components in the shaded area, or
there will be machine/conveyor interferences. Refer
to view A-A in Section 3.2.2.
• Maximum use of PCB real estate - however, single sided
assembly is preferred.
• Components placed outside this envelope will require
manual assembly and can only be assembled after this
process.
0.270
0.070
0.070
Direction of Travel
0.270
View A-A From from Section 3.2.3
PCB Direction of Travel =
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Amphenol TCS
Design For Manufacturability Guideline
TB-2083
Backplane Connector Length Distribution - Press Fit
Requirements
DFM Impact/Benefit
• Preferred to use Backplane Connector sections that
do not exceed a length of 6" (Fig 1)
• Not preferred to use Backplane Connector sections
greater than 6". Lengths from 6"-16" would require
manual processing.
• Capabilities of automated press tooling
• Using shorter section lengths reduces the risk of bent pins
during pre-load.
• Require custom tooling/processes and manual assembly.
• Increase the risk of bent pins during pre-load.
• Consult with Factory on automated capability
• Backplane Connector sections greater than 16" are
not reliably manufacturable.
• Beyond the size of reliable tooling - Consult with
Factory.
• The connector sections should run parallel to the
direction of travel, and be parallel to each other.
(Fig 2)
• Reduces tool movement (rotation) - therefore reduces
cycle time.
Fig 1
Preferred:
Preferred:
Not Preferred:
3"
2"
4"
2"
5"
6"
9"
2"
Fig 2
Modules are parallel to
each other and the direction
of travel into the machine.
Direction of Travel
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Amphenol TCS
5.2.0
Design For Manufacturability Guideline
TB-2083
Top Side Spacing Requirements - SMT & Through Hole Solder
Requirements
DFM Impact/Benefit
• Below, are the requirements for topside component
spacing.
Note: Dimensions are taken from the package, pad or
the lead - which ever is the outer most feature of the
part.
Chip Components
• Spacing allows for process parameters such as placement,
inspection and rework
.025"
.025"
Pad to Pad
Body to Body
Mixed Components
.025"
.050"
PLCC
.050"
PLCC
SOIC
.050"
SOIC
.025"
.025"
DIP
.025"
View from Top Side
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Amphenol TCS
5.2.1
Design For Manufacturability Guideline
TB-2083
Bottom Side Spacing Requirements - SMT & Through Hole Solder
Requirements
DFM Impact/Benefit
• SMT-SMT spacing requirements are the same as
topside, except less package types are allowed - see
section 5.1.
• Spacing between Through Hole Solder components is
based on a .100" grid. Minimum spacing between
leads, whether the leads are from the same or different
components, is .100"
• SMT- Through Hole Solder spacing requirement is
.250" - from Through hole pad to SMT pad or body*,
when devices are grouped by type. See Diagram A.
• SMT- Through Hole Solder spacing requirement is .250"
all around - from Through hole pad to SMT pad or
body*, when devices are intermixed. See Diagram B.
• Spacing allows for process parameters such as
placement, inspection and rework.
• Less than a .100" would result in solder shorts, or would
require solder thieves added to the pads.
• This is the preferred layout, and the spacing allows for
the wave solder fixture to mask the SMT devices during
the wave soldering of the Through Hole Solder parts
• This is an acceptable layout, but not optimal, because
these isolated parts increase the complexity and cost of
the wave solder fixture, and also uses more board area.
Diagram A - Preferred
Through Hole Solder leads
requiring wave solder
*Note: Pad or Body whichever is closer
.250"
SMT devices requiring
masking from wave
solder fixture.
View from Bottom Side
Diagram B - Acceptable
.250
.250"
.250"
View from Bottom Side
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Amphenol TCS
5.2.2
Design For Manufacturability Guideline
TB-2083
Press-Fit Spacing Requirements - Single Sided Press-Fit to All Others
Requirements
DFM Impact/Benefit
• The spacing requirement between single sided Slot style
Press-fit and all other components is .150" along the sides
and whatever the component tolerances allow - on the ends,
which is required on top side. These clearances are taken
from the outer most feature of the housing. See Dia. A.
• The spacing between Press-fit and SMT components on
the opposite side, is .150", but it is measured between the
press-fit hole's annular ring and the SMT component body
- see section A-A.
Diagram A
Connector Housing
Seating Tool
• Automated and manual press-fit clearances for
topside seating tool AND bottom side support tool.
• If spacing requirements are a problem, consider
placing press-fit on one side of the PCB, and SMT
& Through Hole Solder on the opposite side. Space
efficiency usually increases when the technologies
are not intermixed.
Seating tool remains inside the
connector housing - i.e.: HDM,
HD+, and VHDM.
.150"
Top Side
Support Tool
Bottom Side
.150"
.150"
A
A
.150" - Annular
ring to component
body
Section A-A
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Amphenol TCS
5.2.2
•
Design For Manufacturability Guideline
TB-2083
Press-Fit Spacing Requirements - Single Sided Press-Fit to All Others (cont'd)
Requirements
DFM Impact/Benefit
If the seating tool must be outside the connector, the
clearance would be the tool web thickness + .150" or .250"
minimum, whichever is larger. See Diagram B - next page.
• Automated and manual press-fit clearances for
topside seating tool AND bottom side support tool.
Diagram B
Connector Housing
Seating tool is outside the
connector housing - i.e.: power
modules.
Seating Tool
Top Side
Support Tool
Bottom Side
.150"
.250" Min
.150"
Tool web thickness
The clearances shown above are all around the connector for non-slot connectors.
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Amphenol TCS
5.2.3
Design For Manufacturability Guideline
TB-2083
Center-Plane* Press-Fit Preferred Assembly Methods
* Center-plane refers to connectors on both sides of the board, sharing the same holes. (Also called "Mid-Plane")
Center-Plane
Type
Min Board
Thickness*
Connector
Technology
DFM Impact/Benefit
.138" - .173"
HDM
• Not recommended for boards thicker than .170", due
to insufficient pin length and contact wipe on shroud
side. (This is dependant on daughter card design)
2 Pins Sharing 1
Hole
> .220"
VHDM + HSD
2 Pins Sharing 1
Hole
> .280"
• Not recommended for HDM. HDM standard tail
lengths would interfere under this thickness.
Therefore, pins with no "lead-in" would be required,
and this is not a preferred pin type - (see section 4.3)
• Board thickness allows for standard pin lengths with
preferred "lead-in".
Long Tail and
Shroud
(excludes HDM)
HDM
* Overall board thickness tolerance should be considered Example: With HSD - .220" min + 10% board tolerance = .242" nominal
Connector Shroud
PCB
PCB
Previously Seated Long
Tail Connector during
1st-pass Press-Fit
assembly
Long Tail and Shroud
2 Pins Sharing One Hole
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Amphenol TCS
Design For Manufacturability Guideline
TB-2083
5.2.4 Center-Plane Press-Fit Spacing Requirements - Press-Fit to All Others
Requirements
DFM Impact/Benefit
• The spacing requirement between double sided
(mid-plane) Press-fit and all other components is
.150" on both the top and bottom side of the board.
See diagram below.
• Once again, if the seating/support tool must be
outside either connector, the clearance would be the
tool web thickness + .150". See Diagram B in
section 5.2.2
• Automated and manual press-fit clearances for topside
seating tool AND bottom side support tool.
Connector Housing
Seating Tool
Seating tool remains inside the
connector housing - i.e.: HDM,
HD+ only
Top Side
Bottom Side
Previously Seated Connector
during 1st-pass Press-Fit assembly
.150"
Support Tool
.150"
Note:
This assumes that seating and support tool can be used within the housing. For cases where
either tool is outside housing, for reasons such as pin density or to prevent over-seating, the clearance
requirement would be tool web thickness + .150" (.250" min). See section 5.2.2.
5.2.5
Holtite Spacing Requirements – Single Sided Holtites to All Others
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Amphenol TCS
Design For Manufacturability Guideline
TB-2083
Holtites can be assembled on both sides of a PCB but each holtite must be pressed into a separate hole which
contains no other press fit components.
No Components - Keep out area
(Edge Clearance – Reference Only)
Direction of Travel
Clearance required from other components with respect to ?? of hole where holtite is being
inserted.
No components above PCB surface – keep out area.
Component height < .200”
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Amphenol TCS
5.3.0
Design For Manufacturability Guideline
TB-2083
Hole Size and Clearances - Through Hole Solder
Requirements
DFM Impact/Benefit
• Finished hole diameter for round and flat Through
Hole Solder technology must be 0.015” greater than
the maximum lead diameter.
• For rectangular or square leads calculate the
finished hole diameter by adding 0.010” to the
maximum diagonal dimension.
• This ensures the proper sizing of PCB holes respect to the
component lead. Solder flow and quality is greatly
affected by this requirement.
• Square leads must have finished holes that are sized at the
low end of the “rule” to prevent solder defects such as
flooding on the component side of the board.
Note: Minimum Lead Length = PCB thickness + .020"
Square or Rectangular Leads
Round or Flat Leads
Lead
Diameter
(diag.)
Lead
Diameter
Hole
Diameter
Lead
Diameter
Hole
Diameter
Hole
Diameter
Finished Hole size is calculated as follows:
Round or flat leads =
Maximum Lead Diameter + .015"
Square or rectangular Leads = Max Diagonal Lead Dimension + .010"
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Amphenol TCS
5.3.1
Design For Manufacturability Guideline
Hole Size and Clearances - Press-fit
Connector
Type
Minimum
PCB
Thickness
Drill
Size*
Finished
Hole
Size*
VHDM
Signal, Shields
.070
#71 (.026")
.020" Min
.024" Max
VHDM
Power Contacts
.070
#66 (.033")
.0256" Min
.0315" Max
HDM
.070
#66 (.033")
HD+
.093
.0453"
.0370" Min
.0430" Max
See Vendor
Spec
See Vendor
Spec
See Vendor
Spec
Holtite
TB-2083
.0256" Min
.0315" Max
DFM Impact/Benefit
• Minimum PCB thickness, drill size and finished hole
size are the critical design parameters for press-fit
assembly.
• When selecting any press-fit component, follow the
vendor recommended specifications for board
thickness, drill size and finished hole size - paying
particular attention to the finished hole tolerance
requirements.
Hole tolerances are critical for press-fit design.
• Thieving is recommended for better hole size control.
* Note: Both drill size AND finished hole size should be on the drill drawing.
Plated Thru-Hole Details
Finished Hole Size
(after plating)
Drill Size
PCB
PCB
Thickness
Copper
Finish
This document contains proprietary information that is not to be used in any
way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
Page:
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Amphenol TCS
Design For Manufacturability Guideline
TB-2083
6.0 PCB Routing and Design
This section covers assembly processing requirements and limitations to be considered when designing the Printed
Circuit Board. The requirements include:
•
•
•
•
•
Via's and Test Points
Circuit Routing
Silkscreen Marking
Solder Mask Requirements
Board finishes
DFM Impact/Benefit Summary
Most of the requirements defined in this section have the greatest impact on Through Hole Solder, a lesser impact on
SMT, and an even lesser impact on Press-fit. This illustrates why Press-fit is the preferred process, and Through
Hole Solder is non-preferred.
Press-fit is a non-soldering process, and does not have as many requirements as a solder process would. These
requirements include spacing - to prevent shorts and thermal balancing - to prevent cold solder joints.
This document contains proprietary information that is not to be used in any
way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
Page:
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Amphenol TCS
6.1.0
Design For Manufacturability Guideline
TB-2083
Via Placement and Clearances
Requirements
DFM Impact/Benefit
• Via-to-via and via-to-land clearances should be .020"
preferred, and .015" Minimum
• Traces between SMT pads and vias should be as narrow
as possible, and as a minimum, be thinner than the pad.
• The trace between the pad and via should have a
"soldermask dam".
• No vias within an SMT pad
• No exposed vias under SMT components
• Prevents solder shorts and provides enough space for
soldermask application
• Reduces the amount of heat transfer between pad and via,
preventing cold solder joints or component shifting.
• Prevents solder from wicking away from pad and into
via, causes insufficient solder joints
• Minimize shorting conditions
Soldermask
SMT Land
Soldermask covering
the trace
("Soldermask Dam")
.020" Pref.
.015" Min.
Un-masked
Via
.020" Pref.
.015" Min.
This document contains proprietary information that is not to be used in any
way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
Page:
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Amphenol TCS
6.1.1
Design For Manufacturability Guideline
TB-2083
Test Point Placement and Clearances
Requirements
DFM Impact/Benefit
Preferred
Minimum
.050"
.050"
Test Pad using HDM Technology*
.075"
.070"
Test Pad using HD+ Technology*
.100"
.085"
Tooling hole
.200"
.200"
Edge of Component Body
.050"
.030"
SMT Pad
.020"
.015
Via or thru-hole
.020"
.015"
Through Hole Solder Lead
.100"
.100"
Test pad diameter
.040"
.034"
Clearance - Test Pad to:
Test Pad using VHDM Technology*
No test points under
SMT components
• Device access with In-Circuit test probes
• Spacing prevents solder shorts
.030" min
.050" pref.
Tooling Hole
.030" min
.050" pref.
.015" min
.020" pref.
.015" min
.020" pref.
.200"
.015" min
.020" pref.
.100"
This document contains proprietary information that is not to be used in any
way not previously approved by Amphenol TCS Division
Test Pad to Test Pad
is dependent on
connector technology
- see table above*
Release Date:
6-16-04
Rev:
"C"
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Amphenol TCS
6.1.2
Design For Manufacturability Guideline
TB-2083
Thermal Relief
Requirements
DFM Impact/Benefit
• Whenever a hole or via, which will require solder during
assembly, is connected to a solid ground or power plane
the pad should use an approved thermal relief pattern.
See Below.
• Where the ground connection for a Through Hole Solder
component connects to multiple ground planes - use a
thermal relief pad to connect to the inner planes.
• Current carrying capacity of the thermal must be
considered.
• Thermal reliefs should not be used on Press Fit
component holes.
• A non-relieved hole will drain heat away from the solder
connection, not permitting proper solder reflow
temperatures to be reached which causes poor hole
filling, cold solder joints and also impacts rework
capability.
• Thermal relief 's help to provide better control of hole
size, and more consistency in the thickness of plating.
Thermal Relief Pattern Maximize the relief and
minimize the copper, as shown.
(as much as the design allows)
Copper
Minimize
Minimize
Maximize
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way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
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Amphenol TCS
6.2
Design For Manufacturability Guideline
TB-2083
Conductor Routing
Requirements
DFM Impact/Benefit
• Power and ground planes should be buried - they
should not be on an external layer. (IF Power and
ground must be external - see 6.4)
• Prevents handling damage
• Conductor to PCB edge should be a minimum of:
.040" for External layers
.040" for Internal Layers
See Fig 1
• Prevents handling damage
• A conductor must enter a land at 90° angles.
• The conductors that connect (SMT) 1206 and smaller
devices should be consistent in size and connection
point, between the 2 pads. (Symmetry is critical)
See Fig 2
• Prevents solder thieving and part movement during
reflow soldering
• Conductors should not be routed underneath chop
components < 0805
• SMT pads should be copper defined, not solder mask
defined.
• Prevents tombstoning
Not Preferred
Preferred
• Prevents component shifting and cold solder joints.
Not Preferred
Preferred
Fig 2
Fig 1
- Arrows indicate direction of shift
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way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
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Amphenol TCS
6.2
Design For Manufacturability Guideline
TB-2083
Conductor Routing (cont'd)
Requirements
DFM Impact/Benefit
See Fig 1
• When connecting the pads of closely spaced chip
components, (.025" - .050" between pads), it is not
recommended to route traces directly between pads Preferred to route out, and then back in.
• Ensure that traces do not extend beyond pad.
• Do not use one big pad with solder mask defining
individual SMT pads - isolate every pad.
See Fig 2
• Shorts are mistakenly reworked, causing PCB damage.
• SMT pads should be copper defined, not solder mask
defined.
• Prevents component shifting and cold solder joints.
Not Preferred
Not Preferred
Clean up
hanging
traces
• Poor thermal balance - can cause tombstoning and cold
solder joints
Closely spaced
chips with
traces between
the pads or…
Preferred
…one big pad with
solder mask
defining the
individual pads
Route traces out,
across, then back
into the pad.
Fig 1
Preferred
Not Preferred
One large ground
plane with solder
mask defining the
SMT pad.
Fig 2
This document contains proprietary information that is not to be used in any
way not previously approved by Amphenol TCS Division
SMT pad is copper
defined with a trace
going to ground.
Release Date:
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"C"
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Amphenol TCS
6.2
Design For Manufacturability Guideline
TB-2083
Conductor Routing (cont'd)
Requirements
DFM Impact/Benefit
See Fig 1
• When routing leaded SMT devices, do not go directly
between lands, route out, over and back in.
See Fig 2
• No escape routing on the surface layer underneath
Press-fit connectors
• The "H" configuration can cause solder shorts, because
the conductor creates a thermal path
• The "H" configuration appears as a solder short, and is
often reworked.
• Eliminates the risk of damaging or shorting the surface
traces during connector insertion.
Preferred
.015 Min
Escape routing not allowed on top
layer - within the pin field of press-fit
Not Preferred
Fig 2
Fig 1
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way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
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"C"
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Amphenol TCS
6.3
Design For Manufacturability Guideline
PCB Markings - Silkscreen & Etch Requirements
Requirements
•
•
•
•
•
•
•
•
•
•
•
•
Silkscreen Markings
Every component should have silkscreen markings, and the markings should be
shown on the side that the component is inserted from.
Reference designators should be:
1. Clearly visible with the components in place.
2. Used on all components larger than 1206's.
3. Numbered in a logical sequential order.
Polarity and Pin 1 markings, for components that require a specific orientation,
must be indicated on the PCB, and clearly visible with the components in place.
Component outlines should be shown on the PCB, and must be approximate in
size and shape.
Polarized capacitors must have a “+” sign at the positive termination.
Diodes must have a bar at the cathode end of the component.
Pinouts for connectors shall be shown numerically.
Silkscreen location for PCB Label - clear of all Via's, test points and external
etch
Min Serial # and Date code
Min Size = 1.75" X .25"
For high volume applications, the PCB barcode label should have a standard
location by product family, to allow for fixed barcode readers on conveyors Consult with Factory.
Location for ESD Logo for ESD assemblies
Spacing to Pads
•
Legend characters must be kept at least .050″ from SMT pads.
Component outlines must be kept at least .015″ from all pads to prevent bleeding
onto pad areas.
No marking shall be across a pad or contact area.
•
Test point outlines are not preferred.
•
•
TB-2083
Test Points
Etch Markings
An alternative to silkscreen would be to use an elongated pad for pin 1, on SMT
devices, and a square pad for pin 1 on thru-hole devices.
The primary side of the PWB shall contain a minimum of the artwork
revision, title, and layer designation. The secondary side shall contain the
artwork revision and layer designation.
This document contains proprietary information that is not to be used in any
way not previously approved by Amphenol TCS Division
DFM Impact/Benefit
• Indicators required for process
debug, inspection and rework
• Prevent silkscreen interference
with solder process, and false
readings on AOI inspection
equipment.
•
Not used
• PCB Identification
Release Date:
6-16-04
Rev:
"C"
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Amphenol TCS
6.4
•
•
•
Design For Manufacturability Guideline
TB-2083
Solder-Mask and Surface Plane Requirements
Requirements
DFM Impact/Benefit
Solder mask is required to protect board features, such as
conductors and ground planes that are not to be soldered.
LPI (Liquid Photo Imageable) Solder mask is preferred.
• Prevents solder thieving and solder shorts
between conductors and lands.
• Works best with AMPHENOL TCS
processes.
• Provides best adhesion for solder mask preventing peeling and flaking of mask
during assembly processes.
Solder mask over bare copper is preferred.
(No solder mask on any metallic finishes - such as tin-lead or
white tin)
Surface Ground Planes and EMI Shielding
•
When un-masked surface ground planes or EMI Shielding is
required, it is preferred to have clearances in the shielding or
ground planes, for all soldered and press fit components. See
diagram below.
• This prevents solder and sliver shorts.
*Min Clearance
Press Fit =
.200"
SMT =
.040"
Through Hole Solder =
.300"
*Note: Min clearance is around a group of component pads, or if
necessary, each individual pad.
• When connector patterns are close together, combine the clearance
areas of each group, into one large area.
Un-masked EMI Shield or Ground Plane
.040
.200
Connectors that are
close together
should have one
clearance around the
combined pattern.
SMT
Clearance
Areas
Power
Modules
.300"
VHDM
Through
Hole Solder
Board Finish Requirements
.200"
Press-Fit
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way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
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Amphenol TCS
Design For Manufacturability Guideline
Requirements
•
•
•
TB-2083
DFM Impact/Benefit
Board finish requirements vary with board thickness,
process types and design requirements. The requirements
also vary between assembly and the PCB fabrication
processes. Below, is a list of preferred finishes that
minimize those variables.
Press-fit requires tight hole tolerances, relatively soft
plating and a smooth non-abrasive surface finish.
SMT requires a solderable, planar (flat) surface.
• See the matrix below to select the preferred finish that
works best, and results in the highest yields in both
assembly and PCB fabrication.
• Lowest insertion force, greatest mechanical hold
• Minimizes component shifting, solder shorts and maximizes
solder joint quality.
Available Finishes by Assembly Process
Assembly
Process
Process
Variable
Available Finishes
PCB Thickness
Up to .170"
Press Fit
PCB Thickness
.171" - .260"
PCB Thickness
>.260"
Min lead pitch
SMT
> 25 mil
Min lead pitch
< 25 mil
Through
Hole Solder
Tin/Lead Reflowed
Solder Plating
Immersion Tin
Organic
Solderability
Preservative (OSP)*
HASL**
Preferred
Acceptable
Acceptable
Acceptable (VHDM
only up to .150" thick)
Preferred
Acceptable
Acceptable
Non-preferred
Acceptable
Preferred
Acceptable
Non-preferred
Acceptable
Acceptable
Acceptable only up to
.150"/.170" thick
PCB - see above
Preferred
Acceptable
Non-preferred
Acceptable
Acceptable
Acceptable only up to
.150"/.170" thick
PCB - see above
Preferred - except
when there is ground
plane under solder mask
Acceptable - except
when there is ground
plane under solder mask
All
Acceptable
* Note: OSP is a non-conductive, thermal insulating material, and caution should be used when designing direct connections
from a pad on the board to chassis ground, heatsinks, busbars, etc.
** Note: HASL (Hot Air Solder Level) is a process that is difficult to control thickness and flatness. Thicker boards result in
excess plating in holes, which results in tighter holes - causing problems in press fit and through hole solder. In SMT,
where flatness is critical, HASL causes crowned pads, resulting in excess solder - causing shorts.
Non-Preferred Finishes
Finish
•
Immersion Gold over Electroless Nickel
Impact
High material cost :
Press-fit - Hard finish - high insertion forces - causing folded pins
SMT - Excess gold causes gold embrittlement in solder joint
This document contains proprietary information that is not to be used in any
way not previously approved by Amphenol TCS Division
Release Date:
6-16-04
Rev:
"C"
Page:
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DFM Guideline - Design Review Check Sheet
Amphenol TCS
Design Cycle Step: Design Concept ___
Customer:
Pre-Proto ___
Prototype ___
Pre-Pilot ___
Assembly #:
Reviewed By:
TB-2083
Pilot ___
Key1:
Rev:
Date:
Key2
Determine/Minimize Process Flow:
SMT: 1 side __ 2 sided __
Through Hole Solder: 1 side __ 2 sided __
Press Fit : 1 side __ 2 sided __
√ Meets requirements
x Requires a change
? More info required
n/a Not applicable
Hot: Quality and reliability, or safety issue
Warm: Could build without, but not optimal
Cool: Minor Issue
√,x,?,n/a
Item
Sect
Check
(See keys)
Process
Flow
2.3/
4.1
• Minimize process steps - from above:
- Move SMT and Press fit components to one side.
- Change through-hole solder to press fit or SMT
__
__
__
Board
3.1
3.1
3.2
•
•
•
•
•
__
__
__
__
__
__
__
5.1
2.2.1
3.2
•
3.3
•
3.4
•
3.4.1
6.2
•
•
1/16” x 45° Chamfer on 4 corners
Board shape allows for conveyorization
Max size with Press fit or Holtite:
36" x 48" x .450"
Max size with SMT: 24" x 36" x .400"
Max size with Through Hole Solder: 24" x 48" x .200"
- Ensure a .020" solder tail protrusion
- For PCB thickness > .070" change PTH to SMT or
Press-fit; or consider Holtite.
Comp to PCB edge clearance: - w/SMT - .125" min
- SMT on opposite side of press fit - SMT clearance .220"
- w/single side press fit - Top side .150" min
- w/double side press fit - Bottom side .220" min
(3) Asymmetrical Tooling holes located on furthest corners
- Diameter = .125"
- .250” in from PCB edge.
(3) Fiducials located on furthest corners (with SMT)
- Diameter = .040"
- Clearance ring dia. = .080"
(2) Local fiducials required if Comp pitch < 25 mil
Conductor to PCB edge clearance:
- External Layer - .040" min
Change/Comments
Who
Status
__
__
__
__
__
__
__
__
__
__
__
__
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approved by Amphenol TCS, Inc.
Release Date:
6/16/04
Rev:
"C"
Page:
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Amphenol TCS
- Internal Layer - .040" min
• SMT pads should be copper defined, not solder mask
defined
• When EMI Shielding or surface ground planes are
required, ensure proper clearances around component.
- Press-fit - .200" min
- SMT - .040" min
- PTH - .300" min
• Liquid Photo Imageable soldermask over bare copper
• Check PCB finish
- Preferred - Tin/Lead plating, Immersion Tin, OSP
(Non-Preferred - HASL, Gold over Nickel)
__
__
4.1
• Minimize different component values
__
4.6
• Components have clearly marked polarities or pin 1
marking.
__
• PCB has polarity marking that is visible after component
placement
__
__
__
__
6.3
• EPROM's should be socketed using press fit sockets
• Location for ESD logo for ESD assemblies
• Silkscreen location for PCB label - min serial # and date
code - size 1.75" x .25"
• Check silkscreen clearances around pads
5.1
5.2
• Ensure proper component distribution
• Ensure proper component spacing
__
__
• Check for Non-Standard SMT Components: Irregular top
surface, special feeder required, weight, very large,
irregular shape, non-machine placeable.
• Min Comp size – 0402
• Min Lead Pitch - .020”
• Top Side Max dimensions 2.2” x 2.2” x .60” tall
• No SMT connectors where repeated insertion and
removal of mating connector is required
• Bottom Side Max dimensions 2.2” x 2.2” x .15” tall
__
6.2
6.4
6.4
6.5
Components
General
6.3
6.3
Components
SMT
DFM Guideline - Design Review Check Sheet
4.2.1
4.2
4.2
4.2
4.2.4
5.1.0
TB-2083
__
__
__
__
__
__
__
__
__
__
__
__
This document contains proprietary information which is not to be used in any way not previously
approved by Amphenol TCS, Inc.
Release Date:
6/16/04
Rev:
"C"
Page:
Page 73 of 75
Amphenol TCS
5.2.2/
5.2.4
6.1.0
6.1.0
Components
Through
Hole Solder
5.3.0
5.1.0
6.1.2
5.2.1
Components
Press Fit
5.3.1
5.3.1
4.3.1
4.3.1
4.3.5
5.2.3
Componens
Hardware
DFM Guideline - Design Review Check Sheet
• Check spacing between SMT and Press Fit - Ensure .150"
minimum.
• Vias tied to SMT pads - min spacing = .015" with a
solder mask dam
• No Vias within an SMT pad
__
• Hole Size = Lead Diameter + .015 min/.025 max
• Check solder tail protrusion: .020" min/.100 max
• Thermal reliefs in all holes taking Through Hole solder,
especially those tied to a large ground plane
• Group Through Hole Solder components together and
allow a .250” clearance, on solder side, to all SMT
components.
__
__
__
• Hole sizes - follow recommended vendor spec.
• Ensure that Finished hole, Drilled hole AND tolerances
are specified on drill documentation.
• Check compliant pin design
• Check pin lead-ins
• Check - no solid (non-compliant) pin designs
• Check thickness requirement for Center-Plane assembly
• Check power-to-signal module spacing - min 10mm (.394)
(see application notes)
• Connector components specified on internal documents
match customer AVL for manufacturer and
manufacturer part number
• Hardware components specified on internal documents
match customer AVL for manufacturer and manufacturer
part number
•
__
__
TB-2083
__
__
__
__
__
__
__
__
__
•
•
•
•
This document contains proprietary information which is not to be used in any way not previously
approved by Amphenol TCS, Inc.
Release Date:
6/16/04
Rev:
"C"
Page:
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DFM Guideline - Design Review Check Sheet
Amphenol TCS
TB-2083
Additional Input
Item
Problem/Information
Temp
Change/Comments
This document contains proprietary information which is not to be used in any way not previously
approved by Amphenol TCS, Inc.
Release Date:
6/16/04
Who
Rev:
"C"
Status
Page:
Page 75 of 75