Problem with multiple depths

[spfclaridad]

Hi Everyone

I am trying to mill the letters below in the first image. The idea is to use a v groove bit to cut the outline of the letters and then a flat endmill to clear out the pocket. The 2nd image shows the end result with multiple depths in the pocket.

The simulation doesn't show any fluctuations in the z axis during the 2D pocket operation so I can't figure out why there are multiple depths in the actual operation. Everything else is good, just want to achieve a flat bottom for the letters. I attached the test file for reference.

Thanks.

[seth.madore]

What is your machine and what is the material? If you're working with a lighter duty machine and also using a hardwood, there's a high probability that what you're seeing is machine deflection. I suggest using two toolpaths to pocket out this feature, with the first one using positive Axial "stock to leave" that will be cleaned up with the second Pocket toolpath.

[spfclaridad]

Hi Seth, thanks for the quick reply. I'm using an Industrial Craftsman 510 and the material is 1" thick plywood. Would that still fall under machine deflection?

[yd_kwon · Accepted solution]

I'm guessing that the machining conditions were too harsh for a 0.25" end mill, so the bottom part was not machined properly.

If you could ease up on the machining conditions a bit, or use an additional bottom toolpath, you should be fine. Check out the 3rd and 4th toolpaths in the attached file. The Multi-Depth option allows you to machine at multiple Z-levels, as well as additional bottom finishing toolpaths.

Original Toolpath+ Final Stepdown+ Frinal Stepdown & 0.1 Stepdown

[seth.madore]

If you're using a 1/4" endmill that's actually sticking out 1-3/8", that could very well be the issue. Your machine appears to be rather stout, so I'm not too inclined to point fingers at that just yet. But yeah, that's quite the extension on the tool...

Typically, one only wants to extend to the minimum required (plus a small tad for comfort)

[spfclaridad]

Appreciate the responses @yd_kwon and @seth.madore. We were actually able to workaround the issue by changing the ramp to a Plunge (originally Helix), but the finish wasn't perfect. I'll mark this as solved with your suggestion, I'm pretty sure additional toolpaths will do a better job as you guys mentioned. Thanks!