CNC Mill

Study Guide

Prepare to use the DMC2 Mini CNC safely and responsibly from file setup through cleanup.

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1. CNC safety mindset

Use the CNC only after Engineering Safety and CNC certification requirements are complete.
CNC machines move automatically; never assume the tool will only move where you expect.
Keep hands, hair, clothing, cords, and tools away from moving parts and the spindle.
Never bypass guards, covers, teacher checks, or emergency procedures.
Stop and ask for help if anything seems wrong before, during, or after a cut.

2. PPE and machine area

Safety glasses are required during setup, cutting, chip clearing, and cleanup.
Hearing protection may be required depending on material and cut conditions.
Secure long hair, hoodie strings, lanyards, and loose clothing.
Do not wear gloves around the rotating spindle or cutting tool.
Keep the CNC area clear so students can reach the emergency stop and teacher can supervise.

3. Approved materials and stock

Use only teacher-approved materials for the machine, bit, and project.
Confirm stock dimensions before toolpath setup.
Do not cut unknown plastics, metals, composites, or coated materials without explicit approval.
Check that the material is flat, stable, and suitable for the workholding method.
Material thickness matters; incorrect thickness can cause a crash or incomplete cut.

4. Tool and bit awareness

Use the correct bit for the material and operation.
Inspect the bit for damage, dullness, incorrect type, or looseness before use.
Confirm the bit is properly seated and secured by the teacher-approved method.
Do not touch the cutting edge with bare fingers.
Report broken, chipped, dull, or missing bits immediately.

5. CAD/CAM and toolpath review

Verify units, scale, stock size, origin, and setup orientation.
Review toolpath type, cut depth, step-down, feed rate, spindle speed, and tool selection as instructed.
Use simulation/preview to check for collisions, wrong depth, clamp hits, or toolpaths outside the stock.
Never run code/toolpaths that have not been reviewed and approved.
Small setup errors can damage the part, machine, tool, or workholding.

6. Workholding and zeroing

Secure stock with approved clamps, tape, fixtures, or vise methods.
Confirm clamps and fixtures are outside the toolpath.
Set or verify work zero only by the approved class procedure.
Be especially careful with Z-zero; incorrect Z-zero can drive the bit into stock or the machine bed.
Do not adjust clamps, stock, or zero while the spindle is moving.

7. Running and monitoring

Run a supervised dry run, air cut, boundary check, or preview when required.
Stay with the machine and monitor sound, chips, dust, tool motion, and stock movement.
Stop the job if the stock moves, the bit breaks, the machine makes unusual sounds, or the toolpath looks wrong.
Never reach into the machine while it is moving.
Know how to pause, stop, and use emergency stop before the cut begins.

8. Cleanup and reporting

Wait for the spindle and all motion to stop before removing parts or cleaning.
Use approved brushes/vacuums; do not clear chips with fingers near sharp tools.
Remove parts, scrap, chips, dust, clamps, and tools safely.
Return bits, clamps, and setup tools to the correct location.
Report broken tools, poor cuts, unusual noises, loose stock, or machine damage immediately.

Hands-on performance checklist

To earn the badge, students must demonstrate safe material setup, workholding, zeroing awareness, toolpath review, supervised monitoring, emergency response readiness, and cleanup.

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