3D Printing Guide

Detailed instructions for printing Mini-Arm components.

Part-by-Part Settings

Base

Orientation: Flat (large face down)
Supports: No
Infill: 30% (structural)
Notes: Use brim for adhesion

Shoulder & Upper Arm

Orientation: On side (bearing holes vertical)
Supports: Yes (touching buildplate only)
Infill: 20%
Notes: Critical for bearing fit

Forearm & Wrist

Orientation: Servo mount facing up
Supports: Yes
Infill: 20%
Notes: Check servo horn clearance

Gripper

Orientation: Flat
Supports: Minimal
Infill: 15%
Notes: Print fingers separately

Post-Processing

  1. Remove Supports - Use flush cutters, then sand

  2. Test Fit Bearings - May need light sanding

  3. Thread Brass Inserts (optional) - Use soldering iron

  4. Chamfer Edges - Utility knife for cleaner look

Troubleshooting

Parts don’t fit together:

  • Check printer calibration (print a calibration cube)

  • Adjust horizontal expansion in slicer (-0.1 to -0.2mm)

  • Light sanding on tight fits

Weak/brittle parts:

  • Increase wall count to 4+

  • Increase infill to 30%

  • Check for under-extrusion

Warping:

  • Use heated bed (60°C for PLA)

  • Ensure proper first layer adhesion

  • Use enclosure for ABS

File Downloads

STL files are available in the repository:

Mini-Arm/assets/stl/
├── base.stl
├── shoulder.stl
├── upper_arm.stl
├── forearm.stl
├── wrist.stl
├── gripper_base.stl
├── gripper_finger_left.stl
├── gripper_finger_right.stl
└── electronics_mount.stl

Or download from Printables (link TBD).

STEP files for modifications are in assets/cad/.

Next Steps