CNC Training – In-Person

  • Last Updated on February 7, 2023

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Safety

General Safety

  • Do NOT walk away while a job is running.
  • Be attentive / aware of what us going on in the machine.

Personal Safety

  • Glasses/goggles are available in the work space
  • Masks / respirators / etc. is on you to bring at your own discretion!

Physical + Machine Safety

  • Over-heating
  • Chattering
  • Crashes
  • Fires
  • Work-holding Failures
  • A Clean Workspace!

General Process

CAD –> CAM –> Cut –> Clean:

  • CAD (Computer-Aided Design): Carbide Create, or use your own
    • Design a model
    • Set up work parameters – measure WxHxD
  • CAM (Computer Aided Manufacturing): also Carbide Create, or use your own
    • Set reference – usually from top, from bottom if need specific thickness
    • Don’t cut all the way through, leave at least 2 thou stock at bottom
    • Define tool paths
    • Generate your g-code
  • Cut (Running the machine): Carbide Motion
    • Load your file (g-code)
    • Preview! Preview! Preview!
      • Can do a dry run by:
        • zero z-height above the material
        • run the job briefly to eyeball where it is oriented 
    • Run the machine
  • Cleanup
    • Vacuum!
    • Clear workspace
    • Put things back where you found them!

Materials

  • See the main CNC page for machine specs and details on machinable materials.

End Mills

NOT bits !!!  Do NOT put bits into this machine.

A drill bit is designed to bore straight down into the material – metal, plastic, or wood – whereas an end mill is designed for lateral cutting. The two cannot be interchanged.

Choosing End Mills

End Mill selection guide

  • Overall length vs cut length – cut length is the one that matters
  • Upcut vs Downcut (relative to clockwise motion)
  • Upcut: good for bulk passes on wood, cutting plastics
  • Cut sideways instead of drill bits cutting down
  • Different numbers of flutes – chosen based on material.  Single flutes good for acrylic
  • Bit manufacturer’s website
  • Ball nose – good for cutting curves and cleanups

Installing End Mills

  • When removing an end mill, hold it, do not let it fall!
  • Use the two wrenches provided to get it loose
  • Test the fit of the collet with the end mill
  • Put the collet and nut into spindle, then the end mill into the collet
  • Push in the end mill, but not until it bottoms out
  • Start to tighten by hand
  • Tighten until snug with the wrenches, but not too hard
  • Then install fan (round side up) -> push gently, don’t force

Work Holding options

Vacuum before and after.  Don’t mix wood and metal in the vacuum.  If you’re cleaning out

All attached to movable bed
For installing machine screws:

  1. rotate counterclockwise to click to avoid cross-threading
  2. half-tighten all screws before snugging

MDF plate

TODO: source a file for creating new plates.

  1. Mount the plate, there should be 5 screws, 1 in each corner and 1 in the center.
  2. Use double-sided tape to secure your material to the MDF plate
  3. Burnish down the tape
  4. Push down FIRMLY

Vice

  1. Attach sideways with button head screws
  2. Move inner moving jaw against work, then outer moving jaw
  3. Tighten down two vertical screws in outer jaw, then horizontal screw

Corner jig

  • Has consistent right-angle reference at one corner

Flip jig

  • Useful for two-sided machining

Screw-down table

  • Attached to mounting plate
  • Threaded plate that can accept many things
  • Tiger-claw clamps hold things from the side
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