CNC Motion Fundamentals
Understand axes, steps-per-unit, homing, limits and G-code using a pen plotter or motor-only bench.
Learning objective
Understand axes, steps-per-unit, homing, limits and G-code using a pen plotter or motor-only bench.
Components and tools
- Development board
- Current-limited low-voltage supply
- Digital multimeter
- Oscilloscope or logic analyser
- Emergency power disconnect
Safety before motion
- No spindle, laser or cutting tool in student fundamentals lab.nFit physical emergency stop and travel limits.nKeep motion area clear and start at low acceleration.
Practical procedure
- Remove cutters and hazardous tools.nCalculate steps per millimetre.nVerify each axis direction unloaded.nTest limit switches and homing at low speed.nRun a dry pen-plot path inside soft limits.
Measurement checkpoints
| Checkpoint | Expected | Instrument | Safety limit |
|---|---|---|---|
| Steps/mm | Commanded travel matches ruler | Ruler | Defined tolerancenLimit |
Troubleshooting
| Symptom | Check | Corrective action |
|---|---|---|
| Travel wrong | Steps/mm or microsteps incorrect | Recalculate and calibratenHoming crashes |
Engineering sizing tools
Calculate before powering
Mandatory pre-start gate
Machine safety checklist
The simulated enable button remains locked until every item is confirmed.