Lecture Notes: Workflow Comparison Between Onshape and FreeCAD

Introduction

• Objective: Compare the workflow differences between Onshape and FreeCAD for modeling a bicycle seat clamp.
• Format: Video divided into chapters, offering a step-by-step comparison.
• Resources: 3D files available for download.

Initial Setup

• Onshape: Interface might differ due to resizing.
• FreeCAD: Ensure in the Part Design workbench.
• Initial Process: Create a sketch, draw circles, apply constraints, and extrude.

Step 1: Basic Sketch and Extrusion

Onshape

• Sketching: Select top plane, draw circles (39mm, 34mm).
• Constraints: Apply tangent, equality, and dimensional constraints.
• Extrusion: Set depth to 14mm.

FreeCAD

• Sketching: Select XY plane, draw concentric circles (39mm, 34mm).
• Constraints: Similar to Onshape, uses tangency and equality constraints.
• Extrusion (Pad): Set length to 14mm.

Comparison

• Workflow is similar.
• Onshape offers better support for multiple contours.

Step 2: Material Removal

Onshape

• Sketch: On top face, draw center line, rectangle.
• Constraints: Symmetric constraint applied.
• Extrusion: Remove material through all depths.

FreeCAD

• Sketching: Use external projection geometry tool.
• Constraints: Apply symmetry constraint.
• Pocket Operation: Similar settings as Onshape.

Comparison

• Onshape allows direct snapping to solids.
• FreeCAD requires external projections.

Step 3: Creating a Lip

Onshape

• Objective: Ensure a 0.5mm lip thickness.
• Sketch: Draw circle (34.9mm) on bottom face.
• Extrusion: Remove with offset distance.

FreeCAD

• Process: Similar to Onshape, using 'up to face' and offset options.

Comparison

• Both software handle the task similarly.

Step 4: Fillet Addition

Onshape

• Procedure: Add fillets (5mm) to rear edges.

FreeCAD

• Procedure: Similar to Onshape.
• Limitation: FreeCAD cannot create larger fillets exceeding length.

Step 5: Creating Custom Planes

Onshape

• Objective: Create bolt hole, use custom plane.
• Process: Using lines and circles with concentric constraints.

FreeCAD

• Procedure: Similar with external geometry projection requirement.
• Assembly Workbench: Required for stability.

Step 6: Assembly Process

Onshape

• Process: Use assembly workspace, insert clamp, generate bolt.

FreeCAD

• Add-on Required: Fastener workbench needed.
• Assembly Workbench: Fix parts to prevent movement.

Summary & Conclusion

• Onshape: Offers optimized workflow, ease of adding Fasteners.
• FreeCAD: Greater flexibility, no cost, private files.
• Price & Accessibility: Onshape is paid, FreeCAD is free.
• Recommendation: Consider FreeCAD for similar workflow to paid CAD software.

Additional Information

• Community Engagement: Encouraged to share software preferences.