CAD/CAM, digital technologies and emerging technologies
CAD/CAM, digital technologies and emerging technologies is examined through modelling, file formats, CAM output, additive and subtractive manufacture, and newer digital tools.
Core rules
- CAD ranges from 2D drafting to parametric 3D modelling, assemblies, rendering and simulation such as FEA.
- File formats matter: STL is a triangulated mesh for 3D printing; DXF/DWG suit laser cutting and CNC; STEP carries solid geometry.
- CAM converts CAD geometry into toolpaths. Subtractive processes cut material away (CNC router, laser, milling); additive builds it up (FDM, SLA, SLS).
- Laser cutting has a kerf, the width of material removed, typically 0.1-0.3 mm; joints must allow for it.
- 3D printing is strong in complex, low-volume parts but has anisotropic strength and limited accuracy.
- A digital twin is a virtual model updated with real data; IoT connects sensors and actuators over networks.
Worked example
A laser-cut box uses 3 mm ply and finger joints. The laser kerf is 0.2 mm. A slot intended to be a tight fit on 3 mm material should be drawn at 3.0 - 0.2 = 2.8 mm, because the beam removes 0.1 mm from each side. Export the profile as DXF, nest parts to reduce waste, and cut a test joint first. If the fit is loose, reduce the slot by another 0.1 mm and retest.
Traps
Sending an STL to a laser cutter; ignoring kerf; expecting 3D prints to be equally strong in all directions; assuming CAM removes the need for fixtures; confusing DXF with STL.