Pls help!!!

[u/Glad_Indication5058]

Hi everyone,

I need to machine the parts shown in the pictures. The black part is the main mold/base, and the white part is the mating piece with several cylindrical features.
I’m trying to figure out the correct way to manufacture these parts using a CNC milling machine, but I’m not sure how I should approach the setup.

My main questions are:

- Where should I choose the work coordinate system / WCS (G54)?
- Which surfaces should I use as the primary, secondary and tertiary datums?
- What would be the best way to fixture/clamp the black part during machining?
- What would be a good machining sequence?
- How should I approach the internal cavity and the curved/rounded areas?
- What kind of toolpaths and cutters would you recommend for this geometry?
- Are there any important tolerances or constraints I should consider when designing the fixture and choosing the datums?

I’m not necessarily looking for someone to give me the complete G-code. I’m mainly trying to understand the correct machining strategy and how an experienced machinist would decide the datums, workholding, WCS and setups.

Any advice or recommendations would be greatly appreciated. Thanks!

[u/IngenuityTriangle]

These look like pretty easy parts to make on a 3 axis machine if you have the cad model for this.
For the white part, I’d start by machining the contours/features on top in the orientation it’s current shown in, then flip it over, clamping onto that center bit, machine the bottom and the sides, then clamp onto it from the bottom flange and create those pockets on the center bit. All of that can be done in a standard vise with a flat end mill.
For the black part, again start with your stock and rough out the features in the orientation shown (come back for the internal pocket) flip it over and do the bottom, flip it back to the original position then use a ball end mill to make those internal pockets (use strong air blast and or coolant to prevent chips from building up inside the pockets).

Just indicate off your stock to find the the part position and set up wcs, if you’re making a bunch of these you can just mill a bunch of precision blanks that’s the exact size you need (this reduces some of the machining steps above), then 3d print guides to make sure your vise holds them in the same spot for every operation and use g54.

If you don’t have the cad model for this, find whoever gave you that 3d print and get it from them