CNC Training

  • Last Updated on December 5, 2023

Wiki

Ask for training in #help-cnc after reading this doc and understanding the expectations.

There is simply too much to cover in in person training, so you will need to do some homework ahead of time. Please read this section and be prepared before asking for training.

General Process

  1. Read this guide
  2. Watch the prerequisite videos + resources
  3. Get in-person training
  4. Authorization

Prerequisites

Watch these videos before asking for training.  

Our goal is not for you to remember these videos.  We want you to:

  • come away with a rudimentary understanding of the key concepts and process
  • have a foundation to build on in in-person training

Homework X_X

Ask For Training

After you have watched the videos and skimmed this wiki, ask for training.

Arrange a time to come in and get trained, then authorized, to use the CNC machines.

Safety

  • Goggles are available at the space, or bring your own
  • Masks are not required, but something to consider bringing for yourself

Setting Expectations

Culture

You WILL break things.  End mills, materials, etc.

Do not be ashamed.  We’re all here to learn.

If you broke something that is not yours, you need reach out in #help-cnc for help so we are aware and can get it resolved/replaced/etc.  This will also help us gauge over time what the general costs of maintaining the CNC room is.  Help us make this new addition to the space a success!

Intent of Training

This training is not meant to be exhaustive.  The intent is to equip you with enough knowledge to operate the machine safely, comfortably, and know what to start learning more about.

The CNC machine is a great tool, but also has potential for serious consequences.  Always be aware of what is going on in the machine to help keep yourself and others safe, the machine safe and functioning, and the space safe.

General Process

For a detailed overview, see the CNC Training – In-Person page. We will go over this in more detail in-person.

CAD –> CAM –> Cut –> Clean

  • CAD (Computer-Aided Design)
    • Carbide Create, Fusion 360, many many others
  • CAM (Computer Aided Manufacturing)
    • Carbide Create, Fusion 360, many many others
  • Cut (Running the machine): Carbide Motion
  • Cleanup

NOTE: Carbide Create is currently installed on the PCs in the CNC room. It’s unfortunately limited to 2.5D operations. Feel free to explore alternative options for CAD + CAM software. It’s up to you / trial+error on making sure the gcode you end up with can run on Carbide Motion, the current application used to run the Nomad 3.

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

Terminology & Notes

  • OAL – Over All Length – Length of the entire endmill
  • LOC – Length of Cut – Length of the  Cutting Edge of the end mill
  • Upcut vs Downcut vs Compression (relative to clockwise motion)
    • Upcut – clean bottom edge or maximum chip evacuation on deeper cuts
    • Downcut – clean top edge, force the chips downward into the material
    • Compression – clean top & bottom edge, but need the 1st pass below the upcut portion of the bit
  • End Mills cut sideways instead as opposed to drill bits which are intended to bore straight down
  • End Mills can have different # of flutes – chosen based on material.
    • Ex/ Single flutes good for acrylic or some metals
    • Check Bit manufacturer’s website for recommended settings of a given end mill
  • Profiles
    • Ball nose – good for cutting curves and cleanups
    • Square – good for making sharp corners w/ 90 angles
    • V or “Vee” bit – good for engravings
    • etc. etc. etc.
Installing End Mills
  • When removing an end mill: hold it, do not let it fall!
    • Use the two labelled wrenches to get it loose
    • Loosen by hand and pull the end mill out
  • Test the fit of the collet with the end mill
    • The end mill should be snug in the collet, but not have to be forced in
  • Put the collet and nut into spindle (if the collet had to be removed / changed)
    • tighten the nut + collet on SLIGHTLY, just enough for it to stay on without falling
    • do not tighten a collet without an end mill too much; this can break the collet
  • Insert the end mill into the collet
    • do NOT bottom out the end mill
    • most of the shank (non-cutting edge) should be in the collet, more is better, within reason
    • keep any tapered portion of an endmill out of the collet; we only want the shank in the collet
  • Tighten the endmill
    • start to tighten by hand
    • Use the labelled screw to finish tightening.  Just until snug, but not too hard.
  • Install fan (round side up)
    • push gently, don’t force
    • It may help to twist the fan on after it’s halfway on to get it all the way on

Work Holding options

All workholding options attach to the metal bed of the Nomad 3.
For installing machine screws:

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