LOC Design with CAD
Lecture Slides
Learning Objectives
 Learn creating LOC part file using Solidworks
 Learn to do basic dimensioning for the LOC
part file
Lab-on-a-Chip Designs
 For this class you will create two LOC designs per team sequentially
through the semester.
 The two designs are created to adapt your design ideas to two different
chipholder designs and explore different design approaches
 4-Hole Chipholder
 3-Hole Chipholder
 The Chip Requirements document on the Nano Lab Documents Page
describes the requirements of the two designs.
Leveraging Lab 1
Experiences
 What went wrong or did not work well?
How can this “generic benchmark” be improved upon?
 What prevents good performance (e.g., dirt, scratches, poor
seals, channel/well proximity, well geometry, etc.) and how can
this knowledge be used to create a better design and better
practices when testing the design?
 Use your observations! Be creative! Use multiple approaches.
 Your design should be a marriage of function and form!
LOC Design
 Goals
 Optimize fluid flow from staging to detection and waste wells
 Completely fill the detection well for examination
 Design choices
 Number of wells and channels
 Shapes of wells and channels
 Location and size of wells
LOC in Chipholder
LOC Manufacturing Constraints
 LOC designs will be milled from an acrylic wafer
 The milling machine will be using a very small circular bit.
 Should not create any internal sharp corners since a circular
bit cannot make that shape.
 For such features, round the internal corners with a radius of
curvature of at least 200 microns.
 Also no channel or opening can be smaller than 300 microns.
 Extruded part file should be 1/8” (5000 microns) thick with
wells and channels 200 microns deep. Put your group letter on
one side of the chip for identification.
LOC Manufacturing Constraints –
Internal corners
Round the internal corners with a radius of curvature of at
least 200 μm
Deliverables
Design Deliverables
Each team will provide two chip designs for the LOC device – One design for each chipholder
Initial Sketch
Design
Submission for
the 1st chip
Hand-drawn sketch
Required
Preliminary
1st design
Not
required
Dimensione
d
Part File to
GTA
Solidworks Deliverable
Not required
Operational Process
Not required
Not
required
Calculations
Not required
Detection
well Volume
1st Chip Design
Submission
2nd Chip Design Submission
Not required
Not required
Dimensioned
Part File to GTA
Per Chip
Requirements
Per Chip
Requirements
1.Printout of dimensioned
drawings
2. Send Solidworks part file
to GTA
Revised
Per Chip Reqts. Doc.
LOC Specifications
 Chip Diameter – 50800 μm
 Chip Thickness – 5000 μm
 Depth of ALL Features – 200 μm
 Channel widths – 300 μm – 400 μm
 Detection Well Volume – 3 μl
 Round all sharp corners!
 Refer to Project Documentation, Checklist, and Deliverables document
Preliminary Design
 Solidworks Part File emailed to GTA, due per website.

Includes:
Use of 4-hole chip holder design (seed file) to ensure well
alignment
 Dimensioned Part File
 Calculation of detection well volume
 Include separate simple logo to identify your chip
 Instructional Team will provide feedback of the designs
Part file (.SLDPRT) Submission
 Send one part file per design to your GTA
 CONVERT UNITS TO INCHES
 USE FILE NAMING CONVENTION FOR EACH FILE
 EXAMPLE: “LOC_SP15_B_DESIGN1.SLDPRT”
LAB ON CHIP
Semester
And Year
GROUP
CHIP NUMBER
1st Design Submission

Based on the feedback from the preliminary design by
your GTA

Send the part files (.SLDPRT) to TA (insure proper extrusion)

Operational Process

Calculations for all features per Chip Requirements
document
2nd Design Submission

Based on the revisions suggested in the 1st design
Should be drawn on 3 hole chip holder design (seed file) to
ensure alignment.

Dimensioned Chip Design drawing file with top view scaled
up to 3:1.

Send the part files (.SLDPRT) to TA (insure proper extrusion)

Revised Operational Process

Calculations for all features per Chip Requirements
document
Solidworks Part File
 Use the 4 Hole (1st Design) and 3 Hole (2nd
Design) chipholder templates to create your
design.
The templates are in the seed files on the
website (dimensions set to microns and has
chipholder geometry)
Chip Holder Design with Chip
Solidworks Steps
 Go to lab webpage and open Seed File from Solidworks
 Extrude circular shape back into sheet 5000 microns
 Put sketch plane on circular shape
 Turn on visibility of chipholder access holes
17
Solidworks steps (cont.)
 Design your features using the access holes locations.
Put a simple team logo. Connect wells with channels.
 Dimension the size all features
 Finish sketch, features and logo
 Extrude the features into the sheet 200 microns.
 Send part file to GTA with correct naming convention.
18
SolidWorks: Dimensions
Dimensional Constraints can be
added using the Smart
Dimension Button
1.
2.
3.
Click on the entity
Move cursor off object
Click once more to place
dimension
When Constraints are applied
the following dialog box will
appear displaying
• Dimension Name
• Editable Dimension Value
• Options (direction, etc.)
SolidWorks: Dimension
Options
Dimensions can be added
between 2 lines by selecting
the lines sequentially
Between a point and a line
Or even 2 points as long as the
correct direction is chosen ( the
Smart Dimension tool shows
options when moving the
mouse)
SolidWorks: Circles and Arcs
Circles or Arcs can be
dimensioned by the diameter
(Ø) or radius (R)
A circle can be located by its
center point by constraining
both the x and y directions
SolidWorks: Angular
Dimensions
Angular Constraints can be added by
clicking one line and then the other
line. SolidWorks will automatically
assume angular constraint.
Generic Dimensioned Design
Locate dimensions for
ease of readability
Provide dimensions for size
and shape of wells and size
of channels
Team letter only needs
overall width and length
dimension