Articles · Learning path · Intermediate

Designing parts that print well

10 lessons: choosing CAD, STL/3MF/STEP, snap-fits, heat-set inserts, print-in-place hinges, support-free design, joining, finishing, multi-colour and outdoor/food-contact parts.

10 lessons · about 52 min in total

  1. 1 CAD for 3D printing: Tinkercad, Fusion, Onshape, FreeCAD, OpenSCAD, BlenderSix programs makers actually use, what each is good at, parametric CAD vs mesh modelling, and the free-plan terms to read before you sell anything you design. 5 min read
  2. 2 STL vs 3MF vs STEP vs OBJ: which file to send to the slicerSTL is unitless triangles, 3MF adds units, colours and settings, STEP keeps editable true curves, OBJ comes from graphics. Plus export settings that keep holes round. 5 min read
  3. 3 Snap-fits that don't break: strain limits, materials and print orientationHow far a printed cantilever clip can bend before it cracks, worked out from material strain limits, plus taper, root fillet, clearance and which way to print the arm. 6 min read
  4. 4 Heat-set inserts, self-tapping screws or captive nuts: hole sizes and bossesThree ways to put a thread in a printed part, which suits how often you open it, hole sizes from maker tables, iron temperature and how thick the boss must be. 5 min read
  5. 5 Print-in-place hinges that actually move: clearance, orientation, test printHow much gap a print-in-place hinge needs, why Z gaps differ from XY gaps, which way to lay the pin, how to free a stiff hinge, and a short clearance test. 5 min read
  6. 6 Design for no supports: chamfers, teardrop holes, bridges and sacrificial layersShape parts in CAD so they need no supports: chamfers under edges, teardrop and diamond holes, short bridges, split parts, and sacrificial layers for counterbores. 5 min read
  7. 7 Joining 3D prints: CA glue, epoxy, solvent welding, pins and dovetailsMatch the glue to PLA, PETG, ABS or ASA, prepare the surfaces, design joints with pins and dovetails, split big parts, and work with glue safely. 6 min read
  8. 8 Sanding, priming and painting 3D prints: grit order, acrylics and clear coatGrit sequence from 220 to past 600, wet sanding, filler primer, thin acrylic coats, clear coat, how long to let it cure, and why PLA must never be heat-dried. 5 min read
  9. 9 Multi-colour 3D printing options: layer swaps, multi-material, paint, assembliesFive ways to print in colour: layer swap (M600), filament switchers, multiple toolheads, paint, and multi-part assemblies, with the purge waste worked out. 5 min read
  10. 10 Outdoor and food-contact prints: PLA vs PETG vs ASA, and why food safe is hardHow PLA, PETG and ASA handle heat and UV, checked against a car parked in the sun, and why FDM prints rarely meet food-contact rules (FDA, EU). Safer options. 5 min read