A Worksheet Tool for DFM and Cost
Analysis in the NPD Process
www.cloversoft.net
Title
DFM Introduction
•
Design for Manufacturability (DFM) may be described as a
method for evaluating product designs so as to identify
likely manufacturing cost drivers, and then leading to
solutions for the mitigation of these cost drivers.
•
DFM emphasizes cross functional integration and early
evaluation of downstream manufacturing issues. DFM
analysis must therefore be integrated into the New Product
Development (NPD) process. Further the DFM metrics must
be linked to one or more NPD stage-gates.
•
The use of DFM techniques early in the design cycle results
in shorter design delays, easy production transitions, and
higher product quality.
Integrating DFM in the NPD Process
•
An effective NPD/DFM analysis requires that the following three
sequential events occur in an efficient manner:
1.
2.
3.
Capture and deploy all new design and production related
data to the NPD team
Evaluate, quantify and document the manufacturability of
the proposed design
Integrate the manufacturability evaluation into cost
estimating.
•
Pro-DFM is a worksheet based tool that facilitates the
accomplishment of these three events.
•
Pro-DFM provides accurate production cost estimates with little
analytical effort. It is based on a parametric cost model which
focuses on the primary drivers of cost.
Key Metrics Generated
The goal of Pro-DFM is to provide the NPD team with an accurate
estimate of the unit production cost, and then facilitate the
reduction of this cost. Using Pro-DFM you will generate the
following key metrics. These will be used by the NPD team to
evaluate and monitor DFM initiatives.
(i) Estimated Unit Production (EUP) Cost - The EUP Cost is what
Pro-DFM estimates it will cost to make the new product. It
starts with the Direct Part Cost (as provided by vendor
quotes or plant estimating) and then progressively scales
this cost for inventory and considers all DFM Eval factors plus
any supply chain costs.
(ii) Inventory Penalty Cost - Projects the likely additional costs
for maintaining the needed parts inventory. An Inventory
Eval Factor ( 0 to 1 range) is first derived on the basis of
weeks of supply and number of part variants. In the extreme
case where the factor is 1, the part cost is doubled.
Key Metrics Generated
(iii) DFM Part Evaluation Penalty - Projects the likely additional
costs in the processing of this part. A DFM Part Eval Factor
(0-1 range) is derived on the basis of NPD team responses
to a set of scaled response queries. These queries are
divided into three criteria: Procurement, Part Handling, and
Part Geometry.
(iv) DFM Assembly Evaluation Penalty - Projects the likely
additional costs in the execution of this assembly step. A
DFM Process Eval Factor (0-1 range) is first. The evaluation
queries are divided into seven criteria: Process Difficulty,
Equipment Needs, Tooling Needs, Process Setup, Handling,
Inventory and Quality Control.
(v) DFM Part Reduction Opportunity – Projects the likely percent
reduction in direct part costs by eliminating parts. Is based
on the likelihood that individual parts can be eliminated.
Where the opportunity is close to zero then the NPD team
need not focus on part reduction.
Pro-DFM : A Simple Analysis
•
A key problem with traditional DFM analysis is that it tends to
be cumbersome and requires an extensive effort from an
experienced user group.
•
This makes the cost and effort difficult to justify, for most
NPD projects. As a result in many cases DFM analysis is only
being done by large company design groups.
•
Pro-DFM solves this problem by proposing a simple and timetested approach to DFM analysis. This simplicity is achieved
by using the following two strategies:
-
A Multi Factor Scaled Response Model
A MS-Excel® Based Worksheet
A Multi Factor Scaled Response Model
•
Pro-DFM analyses three different factors: (i) parts, (ii)
assembly processes, and (iii) inventory. Each of these is
independently analyzed using multiple criteria, with each
criterion being further divided into sub-criteria.
•
The evaluation metrics are presented in the form of simple
queries, with an anchored response scale. The NPD team
selects the relevant response.
•
This approach bypasses the traditional DFM use of a rigid
knowledge base, and automatically adapts Pro-DFM for each
company.
DFM Part Evaluation
DFM Part Eval Factor (DPi) – Projects the likely additional
costs in the processing of this part.
Criterion: A. Procurement
Sub-Criteria:
A1. Material Knowledge
A2. Sourcing Difficulty
A3. In-bound Quality Control
Criterion: B. Part Geometry
Sub-Criteria:
B1. Dimensional Tolerance
B2. Alignment Ease
B3. Part Symmetry
Criterion: C. Part Handling
Sub-Criteria:
C1. Part Damage
C2. Handling Difficulty
C3. Part Feed Automation
DFM Part Eval
Factor
DFM Part Evaluation
•
Each sub-criterion is evaluated on a 0
(none) to 10 (max penalty) score using
an anchored scale.
•
Use your judgment to select the score
that best represents the specific
situation. If there is insufficient data to
evaluate then select 0.
•
Empirical evidence suggests that DFM
issues could effect part cost by as
much 50%
•
DPi indicates the cost penalty assigned
to the part. If a part is expected to cost
$1.50 and DPi =0.50, then Pro-DFM
projects that a more accurate cost
estimate is $1.50 (1+0.50) = $2.25.
Criterion: Part Handling
Sub-Criterion: Part Feed Automation
Response Scale: Part feeding into
assembly machines will be
(0-2) Automatic on existing equipment
(2-5) Automatic needs new equipment
(4-8) Manual assisted feeding
(5-10) 100% Manual feeding
DPi = 0.5 *
Σk {Wk Xik}/90
Where:
i=1,..,N
Parts in the assembly
k=1,..,9
Part eval sub-criteria.
Wk
Sub-criteria weight (0 to 1)
Xik
Part DFM evaluation scores
DFM Assembly Process Evaluation
DFM Assembly Process Eval Factor (DAj) – Projects the
likely additional costs in the execution of this assembly step:
Criterion: D. Process Difficulty
Sub-Criteria:
D1. Steady Yield Interval
D2. Process Experience
D3. Process Failure Modes
D4. Fastening Type
D5. Output Rate
Criterion: H. Handling
Sub-Criteria:
H1. Container
H2. Orientation
Criterion: G. Process Setup
Sub-Criteria:
G1. Setup Time
G2. Commonality
Criterion: E. Equipment Needs
Sub-Criteria:
E1. Available capacity
E2. New Machine
E3. Process Control Design
Criterion: J. Inventory
Sub-Criteria:
J1. Production Volumes
J2. Work-in-Process
Criterion: F. Tooling Needs
Sub-Criteria:
F1. New Tooling
F2. Complexity
DFM Assembly
Process Eval Factor
Criterion: K. Quality & Testing
Sub-Criteria:
K1. Test Process Expertise
K2. Inspections Specs
K3. Process Capability
DFM Assembly Process Evaluation
•
Each sub-criterion is evaluated similar to
the part evaluation.
Criterion: Setup
Sub-Criterion: Commonality
•
Empirical evidence suggests that DFM
issues could effect the assembly process
cost by as much 70%
•
DAj indicates the cost penalty assigned
to the assembly process step. If the
Response Scale: Setup process that is
common to similar products
(0) 100% commonality
(1-3) 80 to 100% commonality
(4-7) 50 to 80% commonality
(8-10) < 50% commonality
direct assembly process cost is expected
to cost $0.80 and DAj =0.40, then ProDFM projects that a more accurate cost
estimate is $0.80 (1+0.40) = $1.12.
DAj = 0.7 *
Σp {Vp Yjp}/190
Where:
j=1,..,M
Steps in the assembly
p=1,..,19
Assembly eval sub-criteria.
Vp
Sub-criteria weight (0 to 1)
Yjp
Assembly DFM eval scores
Inventory Evaluation
Inventory Eval Factor (DVi) – Projects the likely additional
costs for maintaining the needed parts inventory:
DVi = 0.4*{(Bi-1)/10} + 0.6*{Si/52}
Where:
i=1,..,N
Parts in the assembly
Bi
Number of part variants (color, etc.)
Si
Projected weeks of supply per order
• The inventory requirements for a part are often a function of
several design parameters.
• When a part has many variants on the basis of color, size, labels,
etc., this can have a significant impact on inventory levels.
• The part type (material, production process, etc.) will influence the
order batch size and hence the weeks of supply to be inventoried.
Estimated Unit Production (EUP) Cost
The EUP cost derivation considers all DFM Eval factors plus
other factors as shown below.
EUP COST = {Direct Part Cost (i) (DPi + DVi + Indirect Rate) +
Inbound Supply Chain }
+ {Direct Assembly Cost (j) (DAj + Indirect Rate) + Outbound
Supply Chain }
-
Unit Direct Part Cost
DFM Part Penalty
Inventory Penalty
Supply Chain Cost
Indirect Costs
PART
COSTS
-
Process Labor Rate
Process Equipment
Process Setup
Quality Loss
DFM Process Penalty
Indirect Costs
ASSEMBLY
PROCESS
COSTS
ESTIMATED UNIT
PRODUCTION COST
DFM Part Reduction Opportunity
• The assessment is based on the likelihood a part can be
eliminated and why. For each part you will select from the list of
reasons the most applicable reason.
• The likelihood evaluations are used to derive the Part Reduction
Opportunity as follows:
{P[Elimination](i) x Direct Part Cost(i) }/ Total Direct Part Cost
Prob of
Elimination
(0.0)
(0.0)
(0.2)
(0.3)
(0.4)
(0.5)
(0.7)
(0.8)
(1.0)
(0.0)
Reason
No - Provides Primary FR"
No - Motion Requirements"
No - Material Restrictions"
No - Assembly Restrictions"
Yes - Possible to Transfer FR"
Yes - Possible to Reduce Count"
Yes - Easy to Transfer FR"
Yes - FR maybe Eliminated"
Yes - Redundant FR"
No - Unable to Evaluate"
A MS-Excel® Based Worksheet
• Pro-DFM is based on the
popular MS-Excel® program
and therefore requires
minimal training. MS-Excel®
provides a familiar interface
and file portability.
• The Pro-DFM software is
organized into a series of 14
worksheets. All sheets are
linked together by our
backend macro program.
• Data is entered through popup windows, and the
worksheets are automatically
updated.
Pro-DFM Worksheets
FRONT:
1.
2.
REPORTS: 3.
4.
5.
6.
DATA:
7.
8.
9.
10.
11.
12.
13.
HELP:
14.
NPD/DFM Analysis Cover Page
DFM Action Item Log
NPD/DFM Exec Summary Report
EUP Cost Report
Analysis of Prod Cost by Plant
DFM Evaluation Summary Report
Part/Material Data
DFM Part Evaluation Data
Assembly Process Data
DFM Process Evaluation Data
Assembly Process CostCalc
Supply Chain Costs
Alternate Plant
Definitions Help
Data Requirements
• Listed here are the data required for
creating a Pro-DFM file and running the
analysis.
• You need not wait to have all the data to
start the analysis.
• Most of the analytical components use
numerical data. Where the data is not
available enter the default (usually zero)
value.
• Pro-DFM also promotes data transparency
in the NPD team. Some data is recorded
for this purpose and not used in the DFM
or costing analysis (e.g. Quality
Requirements). This data, though, is found
to promote a more reliable DFM
evaluation.
• The development time data is used to
support project planning and estimate
what design changes can be made without
effecting the end date.
PART DATA:
1.
2.
3.
4.
5.
6.
7.
Product BOM including material specs
Design drawings or schematics
Part function and key features
Test method specs
Quality control specs
Inventory & supply chain data
Development time
ASSEMBLY PROCESS DATA:
1.
2.
3.
4.
5.
6.
7.
8.
Assembly process plan
Tooling requirements
Equipment requirements
Labor and Equipment unit utilization times
Setup times
Quality rejection rates
Production volumes and unit batch sizes
Development time
Adding Parts
Step #1 – Add parts to your ProDFM file. A part will typically be a
BOM item retrieved from the
product specifications.
Step #2 – Complete the DFM
evaluation of all added parts. You
can view the anchor scales for
each sub-criterion as you enter
the evaluation.
Adding Assembly Process Steps
Step #3 – Add assembly process
steps to your Pro-DFM file. The
steps can be retrieved from a
process plan document.
Step #4 – Complete the DFM
evaluation of all added assembly
steps.
CostCalc Utility for Assembly Process Costs
For each assembly step you can either directly
enter the hourly costs or derive it using the inbuilt
Pro-DFM CostCalc utility.
LABOR DETAILS: Can add up to 4 operators. For
each operator specify the (i) Hourly Rate (ii)
Productivity - relative to benchmark production rate
and (iii) Busy Time - what % of time is dedicated to
this step, if he operates 2 machines then 50%, if he
works for 10 minutes in a 100 minute run then
10%.
EQUIPMENT DETAILS: Can add up to 3 equipment.
For each equipment specify the (i) Hourly Run Rate
- cost to operate the machine minus labor (ii)
Utilization - % of run time that the machine is busy
on this step, if a blender is needed for 5 minutes in
a 50 minute step then 10% and (iii) Setup Time time to setup a batch run.
Example – Pencil Sharpener
The design of an electric pencil sharpener (shown below) will be used to demonstrate the
use of the Pro-DFM software. There are 20 parts and 4 assembly process steps.
The design is based on a common model that is readily available in any office supply store
(e.g. Staples). This product has an average retail price of price of $11.50. The target EUP
price should therefore be $5.75.
EUP Cost Report
Provides summarized costing details for each part and each assembly process step. Lets
you see the cost roll-up and cost significant parts and assembly process steps. Provides
a starting point for direct cost reduction initiatives.
The DFM and Inventory penalties are listed. DFM activities initiatives should initially
focus on the highest penalties.
4. ESTIMATED UNIT PRODUCTION COST REPORT
PRODUCT =
Electric Pencil Sharpener
ESTIMATED UNIT PRODUCTION (EUP) COST =
$6.788
REPORT DATE = 8/26/2005
◄TOTAL
$1.443
◄COST RISK
$1.320
DIRECT TOTAL PART COST =
$3.131
DIRECT TOTAL ASSEMBLY COST =
$2.196
INDIRECT TOTAL PART COST =
$0.313
INDIRECT TOTAL ASSEMBLY COST =
$0.549
OUTBOUND UNIT SUPPLY CHAIN COST =
$0.130
COST RISK ▼
$2.875
$0.079
42.35%
1.17%
INBOUND UNIT SUPPLY CHAIN COST =
$0.470
COST RISK ▼
TOTAL UNIT PART COSTS ►
$3.914
$1.364
RELATIVE TO EUP COST ►
57.65%
20.09%
TOTAL UNIT ASSEMBLY COSTS ►
RELATIVE TO EUP COST ►
◄ DFM+INV PENALTY
INDIRECT PART RATE =
10%
INDIRECT PROCESS RATE =
25%
EUP Cost Report
PART & MATERIAL COST ESTIMATES
PART #
PART/MATERIAL
COUNT QTY
UNIT PART COST
INVENTORY EVAL
FACTOR
DFM PART EVAL
FACTOR
INV+DFM COST ESTIMATED PART
PENALTY
COST
PART SUPPLY
CHAIN COST
1
Top cover
1
$0.120
0.16
0.11
$0.032
$0.152
$0.02
2
Bottom Cover
1
$0.090
0.16
0.16
$0.028
$0.118
$0.02
3
Shaving Tray
1
$0.060
0.10
0.17
$0.016
$0.076
$0.01
4
Magneto
1
$0.320
0.15
0.17
$0.103
$0.423
$0.04
5
Long Screw
2
$0.040
0.17
0.23
$0.032
$0.112
$0.00
6
Fine thred phillips head screw
1
$0.030
0.15
0.21
$0.011
$0.041
$0.00
7
1/2" phillips head screw
2
$0.010
0.17
0.15
$0.006
$0.026
$0.00
8
3/4" long phillips head screw
3
$0.010
0.17
0.22
$0.012
$0.042
$0.00
9
Washer
1
$0.010
0.13
0.24
$0.004
$0.014
$0.00
10
Electric twist caps
4
$0.020
0.08
0.13
$0.017
$0.097
$0.04
11
Inner Housing
1
$0.031
0.15
0.20
$0.011
$0.042
$0.05
12
Sensor
2
$0.380
0.17
0.20
$0.283
$1.043
$0.08
13
Electric Cord
1
$0.140
0.08
0.14
$0.031
$0.171
$0.04
14
Motor shaft brace
1
$0.060
0.15
0.12
$0.016
$0.076
$0.02
15
Motor
1
$0.320
0.24
0.13
$0.118
$0.438
$0.07
16
Big Gear
1
$0.060
0.17
0.15
$0.019
$0.079
$0.00
17
Small Gear
1
$0.040
0.17
0.26
$0.017
$0.057
$0.00
18
Thin Metal Shield
1
$0.010
0.13
0.19
$0.003
$0.013
$0.01
19
Shaving Guard
1
$0.040
0.15
0.13
$0.011
$0.051
$0.02
20
Cutter Assembly
1
$0.042
0.17
0.25
$0.018
$0.060
$0.05
$0.788
$3.131
$0.47
TOTAL UNIT PART & MATERIAL COST =
EUP Cost Report
ASSEMBLY PROCESS COST ESTIMATES
STEP #
ASSEMBLY PROCESS
PROD RATE / HR PROD BATCH SIZE
PROCESS COST RISK
RANGE (%)
PROCESS COST/HR
SETUP COST/HR
BATCH SETUP
TIME (hrs)
QUALITY REJECT
RATE
DFM PROCESS
EVAL FACTOR
ESTIMATED
ASSEMBLY COST
1
Plastic Injection
120
1200
2%
$22.000
$16.00
0.50
2%
0.17
$0.225
2
Casting
120
800
2%
$44.500
$20.00
0.75
3%
0.13
$0.450
3
Electrical Circuit Assembly
120
300
3%
$44.467
$20.00
1.00
1%
0.21
$0.520
4
Cutter Set Assembly
90
800
5%
$20.000
$30.00
0.50
2%
0.20
$0.292
5
Final Assembly
60
800
5%
$32.467
$0.00
1.00
2%
0.29
$0.709
$0.111
$0.040
$0.363
$2.196
TOTAL UNIT ASSEMBLY PROCESS COST =
DFM Evaluation Summary Report
Provides aggregated details of the DFM Evaluation. First part aggregates the part and process
evaluation responses. Displays the average and maximum scores, plus alert frequency. An alert
is issued when the score to any response is above your specific alert limit. Second part is
divided into DFP Part Analytics and DFM Process Analytics. Presents data graphically and
identifies the part and process with highest DFM scores, plus the most penalized DFM criterion.
DFM Evaluation Summary Report
NPD/DFM Executive Summary Report
Summarizes the results of the DFM and cost analysis, and should be reviewed first by the NPD
team. Divided into the following sections: (i) Unit Production Cost Summary, (ii) Development
Time Summary, (iii) DFM Evaluation Summary, (iv) Production Cost Analytics, and (v) Design
Development Time Line.
3. NPD/DFM EXECUTIVE SUMMARY REPORT
PRODUCT =
Electric Pencil Sharpener
PLANT = New Jersey
ESTIMATED UNIT PRODUCTION (EUP) COST =
ESTMATED DEVELOPMENT TIME (EDT) (Weeks) =
$6.788
8.00
REPORT DATE = 8/26/2005
◄TOTAL
$1.443
◄TIME TO LAUNCH
7.00
◄COST RISK
$1.320
8.00
◄PARTS
◄DFM+INV PENALTY
◄PROCESSES
UNIT PRODUCTION COST SUMMARY
PARTS ANALYSIS
ASSEMBLY ANALYSIS
INDIRECT
28
RATIO TO EUP ▼
5
RATIO TO EUP ▼
TOTAL UNIT PART COST =
$3.914
57.65%
TOTAL UNIT ASSEMBLY COST =
$2.875
42.35%
TOTAL PART COST RISK =
$1.364
20.09%
TOTAL ASSEMBLY COST RISK =
$0.079
1.17%
MAXIMUM PART COST =
$5.278
77.75%
MAXIMUM ASSEMBLY COST =
$2.954
43.51%
NUMBER OF PARTS =
NUMBER OF PROCESS STEPS =
PRODUCT DEVELOPMENT TIME SUMMARY
PARTS ANALYSIS
ASSEMBLY ANALYSIS
PART DEV TIME DURATION (Weeks) =
7.00
RATIO TO EDT ▼
PROCESS DEV TIME DURATION (Weeks) =
8.00
RATIO TO EDT ▼
REQD. PART DEV TIME (Weeks) =
30.00
428.57%
REQD. PROCESS DEV TIME (Weeks) =
17.50
218.75%
PART DEV TIME RISK (Weeks) =
8.25
117.86%
PROCESS DEV TIME RISK (Weeks) =
8.00
100.00%
MAX
AVERAGE
FACTOR SUM
COST PENALTY
9.00
2.54
DFM PART EVAL FACTORS =
3.56
$0.402
9.00
2.85
DFM PROCESS EVAL FACTORS =
1.00
$0.363
PART INVENTORY EVAL FACTOR =
3.02
$0.385
DFM EVALUATION SUMMARY
PARTS ANALYSIS
PART DFM EVAL SCORES =
PROCESS DFM EVAL SCORES =
PART REDUCTION OPPORTUNITY =
15.96%
ASSEMBLY ANALYSIS
INDIRECT PART =
10%
INDIRECT PROC =
25%
NPD/DFM Executive Summary Report
PRODUCTION COST ANALYTICS
DFM Part + Inventory Penalty Cost
EUP Cost Roll-up
$0.30
Supply Chain
$0.60
DFM Part Penalty
$0.40
$0.25
$0.20
DFM Process Penalty
$0.36
$0.15
$0.10
Part Inventory
$0.39
Indirect
$0.86
$0.05
$0.00
Top cover
Long
Screw
Washer
Electric
Cord
Small
Gear
DFM Process Penalty Cost
$0.16
$0.14
$0.12
$0.10
$0.08
$0.06
$0.04
$0.02
$0.00
Direct Part
$2.34
Direct Assembly
$1.83
Plastic
Injection
PART DEVELOPMENT
TIME
PROCESS DEVELOPMENT
TIME
Casting
1
Plastic Injection
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
WEEKS
0.00
1.00
2.00
3.00
4.00
WEEKS
5.00
6.00
7.00
8.00
Casting
Electrical
Circuit
Assembly
Cutter Set
Assembly
Final
Assembly
NPD/DFM Executive Summary Report
DESIGN DEVELOPMENT TIME LINE
PART DEVELOPMENT TIME (Planned + Risk)
Cutter Assembly
Shaving Guard
Thin Metal Shield
Small Gear
Big Gear
Motor
Motor shaft brace
Electric Cord
Sensor
Inner Housing
Electric twist caps
Washer
3/4" long phillips head
1/2" phillips head screw
Fine thred phillips head
Long Screw
Magneto
Shaving Tray
Bottom Cover
Top cover
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
WEEKS
PROCESS DEVELOPMENT TIME (Planned + Risk)
Final Assembly
Cutter Set Assembly
Electrical Circuit Assembly
Casting
Plastic Injection
0.00
1.00
2.00
3.00
4.00
5.00
WEEKS
6.00
7.00
8.00
9.00
10.00
Getting Started
•
Following this brief introduction you are now ready to start a Pro-DFM project. You
will be provided with the following files:
1
ProDFM-2 - This file is of the type MS-Excel® Add-in (.xla extension), and
requires MS-Excel® XP or later to run.
2.
Pencil Sharpener – A MS-Excel file
3.
ProDFM User Manual – A .pdf file
•
Please read the User Manual to learn how each function is performed. Print out
Sheet.14 Help so that you can quickly reference all the definitions.
•
We recommend that you browse through the Pro-DFM example provided to you
(Pencil Sharpener file) to familiarize yourself with the different worksheets and the
associated data requirements.
•
Create an appropriately named folder on your computer and transfer the ProDFM-2
file to this folder.