4.3. Tutorial: Mechanical Design using the Laser Cutter

These notes are meant to accompany an in-class tutorial presentation, and may not necessarily stand alone. For general reference, see also Mechanical Behavior.

Image: Stanford OpenArm


Image: Planetary Gear by Rob Ives


Image: joinery example from Makezine


Image: basic pivot joint

../_images/simple-joint-iso.PNG ../_images/simple-joint-side.PNG

4.3.1. Overview

This is a quick take on practical mechanical design techniques for machines we will fabricate using the laser cutters. First, some terminology:


  • plate, gusset, I-beam
  • truss
  • interference fit (or press fit)
  • free fit
  • snap fit, tabs and slots


  • degree of freedom (DOF)
  • joint
    • hinge or pivot (rotational joint, 1 DOF)
    • translational joint (linear joint, 1 DOF)
    • universal joint (two pivots, 2 DOF)
    • ball joint (spherical joint, 3 DOF)
    • flexure


4.3.2. Laser Considerations

  • choosing a 2D or 3D drawing program with DXF output in millimeters
  • flat stock
  • designing in layers
  • designing with right angles
  • joinery to create 3D from 2D parts
  • kerf
  • sharp inside corners
  • tolerance and precision
  • materials
    • acrylic
    • cardboard
    • thin plywood
    • paper
    • fabric, leather, Delrin (acetal)
  • fasteners (screw, nut, bolt)
  • adhesives
  • Dave Touretzky’s 15-294 Laser Cutter Intro