CNC Training – In-Person

  • Last Updated on February 23, 2023

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General Process

CAD –> CAM –> Cut –> Clean

CAD (Computer-Aided Design)

  • Design a model
  • Measure WxHxD of your material

CAM (Computer-Aided Manufacturing)

  • CAM (Computer Aided Manufacturing): also Carbide Create, or use your own
  • Set the Zero point for x, y, and z axis.
    • Note whether you’re zero-ing the z-axis on top of your material or the machine’s bed
  • 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)

  • Initialize the machine
    • Power it on
    • Install the 1st end mill + matching collet for your job
    • Put the fan back on !
    • Let it initialize w/ the end mill installed
    • Install workholding + material
  • Use an appropriate workholding option for your job
  • Install your material into the workholding option
  • Set your Zero – In the Run tab of Carbide Motion
    • Close the door!
      • AND Be sure the safety mechanism is engaged, or you won’t be able to zero anything.
      • Never tamper w/ the safety mechanism >_<
    • Move the tip of the end mill to where you want your x, y, and z zero points to be
      • AVOID pushing/ramming/smashing the end mill into your material
        • Lower the increment of movement as you get the end mill closer to the material
        • Remember the “paper test” for zeroing your z-axis; you should be able to just get a piece of paper between the endmill and you material
      • NOTE you can individually zero out each of the x, y, and z axis instead of all at once if necessary.
        • Ex/ If your z-axis zero is on the machine bed, you will have to zero the z next to your material, THEN zero your x and y axis above your material
  • Load your file (g-code)
  • Preview! Preview! Preview!
    • Can preview the toolpaths and machine movements in the ISO view tab
    • Can do a dry run by:
      • zeroing z-axis above the material and running the job above your material
  • Safety
    • Goggles are available
    • Consider bringing a mask
  • Run the machine
    • Stay near the machine while it is running
    • Listen and look for issues, chattering, workholding failures, fires, broken endmills, etc.
    • Look at your chip size.
      • Should have chips of material that sink to the bed of the machine.
      • Not too big, not too small.

Cleanup

  • Remove the endmill, put it back in it’s labelled container.
  • Vacuum!
  • Clear workspace
  • Put things back where you found them!

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.

End Mills For Training

There is a set of end mills labelled for training only, intended for to be used for … training only. These will be available to use during the in-person training.

Do not use them outside of training.

Keep them in the 2nd drawer w/ the machining reference books and away from anything else.

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
  • Shank Diameter – Determines what collet the endmill will need
  • Cutting Diameter – The diameter of the cutting edge of the endmill. This property may not be relevant, depending on the profile/shape (ex/ v-bits).
  • Helix Angle – generally 30°, see guide(s) for more info
  • Flute Count – number of flutes on the end mill; the material you cut dictates how many flutes you need
  • Material – one of many factors determining what materials the end mill can cut
  • Coating – see guide(s) for info / tips
  • 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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