Day 9: (Wed Feb 15, Week 5) SolidWorks Mold Design

Notes for 2023-02-15.

New Assignments

New individual assignment, due Monday: Part B: Open Mold Design. We will try to get through as many of the CAD steps as possible during class, but you are responsible for finishing the mold design and fabricating your 3D-printed mold.

Please submit your 3D print jobs no later than Thursday; it takes time to approve jobs, and the printer queue can run a backlog. If your design requires support material, please visit the output queue no later than Monday morning to put your mold in the dissolving bath, then retrieve it a few hours later. It needs to be dry before class.


In order to make up for the cancelled class, I’d like to finish the mold design today and still have the mixing workshop Monday:

  • Wed Feb 15, Day 9: SolidWorks mold design workshop

  • Mon Feb 20, Day 10: silicone mixing and molding workshop


  1. Discussion of open-mold design.

    1. Design Example: Open Molded Soft Silicone Actuator

    2. demo photos (not online).

    3. draft notes on Small Batch Mixing Protocol.

  2. SolidWorks open mold workflow demonstration.

    1. Model a part with internal cavities to be fabricated in silicone. The outer faces will need to be flat as they will be formed by the open top of each mold.

    2. Choose a splitting plane and divide into two separate parts. The split surfaces should be concave with no overhangs, as they will be each formed by a mold.

    3. For each separate mold:

      1. Model a mold part larger than the part to fabricate. Note: if your part is small, both part halves can be subtracted from a single mold block, which saves on printing cost.

      2. Create an assembly from the mold.

      3. Add the fabricated part(s) to the assembly and add mates to align inside the mold part.

      4. Edit the mold part in the assembly context and add a Cavity feature to subtract the part.

      5. Open the mold part, inspect, and export as a STL for fabrication.

    4. Upload to Skylab (the 3D printer queue).

      1. For details: IDeATe 3D Printing Guide

      2. Please add the following to the comments field: “Please charge to 16-480 Creative Soft Robotics.”

      3. For reference, the price should run no more than about $10.

  3. Mold design workshop.

    1. Using SolidWorks (or your alternative 3D CAD), please proceed through the process of generating a pair of open mold designs for fabricating your part.

    2. I will circulate and answer questions.

    3. When you are ready, I will review your design.

  4. Time permitting: quick review of project sketches with each individual pair.

SolidWorks Resources

SolidWorks Terminology Summary

  • parametric model

  • design intent

  • part

  • assembly

Parts and Sketches

  • plane

  • sketch (2D)

  • feature

  • feature tree

  • relation

Sketch Geometry

  • lines

  • circles

  • ellipses

  • polygons

  • reference features

  • centerline

  • construction line

  • point

Sketch Relations

  • horizontal

  • vertical

  • dimension

  • coincident

  • collinear

  • dimension

  • symmetric

  • concentric

  • perpendicular

  • parallel

  • coradial

Essential Mold-Related Operations

  • Split

  • Cavity

  • Save As STL