Spring Design Tool

A powerful software tool designed to facilitate the creation of lightweight torsion springs.

📥 Download

Get the latest release.

🚀 Installation

For MATLAB Users

• Ensure you have a MATLAB license.
• Double-click on spring_design_tool.mlappinstall (found here).
• Open MATLAB and find the tool under My Apps.

Without MATLAB License

• Compatible with PCs.
• Open the DesignToolStandalone zip folder
• Check the readme.
• Double-click spring_design_tool to install and open the Design Tool as a desktop application.

🛠️ Usage

• Hover over labels or data fields for explanations of each input.
• For 'Optional' arguments, inputting 0 lets the tool calculate values automatically.
• Once inputs are set, click Create Spring to generate your custom design.
• For optimal performance, enter a 'Run Time' of 15-30 seconds.
• If satisfied with the design, select your output 'File Type' and 'Units' and click Download Design.
  • Choose the 'File Type' based on your CAD software (e.g., .txt for Solidworks, .csv for Fusion360 and Onshape).

📄 Outputs

The tool outputs xyz-coordinates for your spring design with various curve options:

• Raw: The precise spline of one flexure as optimized by the tool (no added tip or fillets).
• Pattern: The raw spline of one flexure, but with circular tip and fillets added.
• Wedge: A single wedge-slice of the full spring geometry (includes outer rim/dowel hole).
• Inner: The inner curve of the full spring, including all flexures, tips, and fillets.
• Outer: The outer curve of the full spring with all semi-circular cutouts for the dowels.
• Cam_profile: The complete curve of the camshaft, including all gear-like teeth.
• Cam_raw: The curve of the contact surface (no fillets or extra geometry).

If you forget which settings you selected for your spring design, check README_spring_properties in the output folder!

🧩 Create Solid Model

For OnShape Users (recommended)

• Ensure you downloaded the curves as .csv files with m for units.
• Copy this template to your preferred OnShape folder.
• Import raw_m.csv and cam_raw_m.csv to your copied workspace.
• In the Variable Studio, update workspace variables with the values found in README_spring_properties (in the output folder).
• In the Part Studio feature tree, edit Cam_Raw CSV and Raw CSV by updating their respective tables to reference your new .csv files.
• Open the first sketch (Spring & Cam Geometry) and resolve errors:
  • Delete curves with broken relationships.
  • Click on new curves and convert to sketch (u).
  • Make any adjustments to ensure the geometry is closed.
• Exit the sketch and resolve any final details (the fillets often lose their reference).
• Make any custom modifications you'd like!

For Other CAD Software

You will need the following resources to import the spring geometry:

• SolidWorks: Curves Through XYZ Points
• Fusion 360: ImportSplineCSV (UTILITIES > ADD-INS > Scripts and Add-Ins)
• Other: Search for tutorials using "CAD_SOFTWARE_NAME curve through xyz points" for guidance.

⚡ Quick Model

• Spring:
  • Import inner and outer using your preferred CAD package.
  • Start a sketch on the same plane and pull both curves into the sketch.
  • Extrude the enclosed area.
• Cam:
  • Import cam_profile and extrude.

🔍 Detailed Model

• Spring:
  • Import raw using your preferred CAD package.
  • Start a sketch on the same plane and pull the raw curve into the sketch.
  • Sketch the rim wedge to close the open end of the flexure.
  • Extrude the enclosed area.
  • Sketch and extrude the flexure tip according to 'tip radius' and 'contact radius' as defined in README_spring_properties.
  • Add fillets at the tip geometry (same radius as 'tip radius') and flexure root (approximately 1/2 the rim thickness).
  • Use circular patterning to duplicate the model based on the number of flexures (n) defined in README_spring_properties.
• Cam:
  • Import cam_raw and pull the curve into a new sketch on the same plane.
  • Sketch the root geometry allowing clearance for the flexure tip.
  • Close the rest of the sketch.
  • Extrude.
  • Mirror the body across the centerline of the flexure.
  • Use circular patterning for the cam by the number of flexures (n) defined in README_spring_properties.

📚 Examples

Explore possible applications for torsional springs, and notice the mass and volume savings that can be achieved with this design tool: