Pocketing holes for spoilboard threaded inserts, decrease run time?

Alrighty, I designed what i thought was a nice pattern of 11x11 8mm holes that will be 38mm deep in MDF, went to run the program & it started the first hole about 4 1/2" off of where it was supposed to go, think I got that straightened out, but the new gcode i’m doing is just a test for one hole… it says it’s going to take 2 minutes just to pocket that one hole & around 80 minutes for all 121.

That seems rather long for a single hole, but I’m sure I don’t have anything optimized yet.

I’m using a 1/4" spiral upcut bit, going to turn at 18,000rpm, here’s the other specs: plunge rate= 304.8mm/min, feed rate= 2286mm/min, 3mm depth per pass, 3.175mm stepover (most of these were “stock” settings in carbide create for a 1/4" spiral upcut bit).

Need some tips on what I can safely run that won’t take forever, but still not push the machine to it’s limits.
Can I bump up the depth per pass? I believe the retract height is set around 6mm.

Hi Buggman - I’m not sure what CAM program you are using, but a bore operation might be faster than a pocket. Regardless, I happen to be Fusion right now and did a quick sim of your operation and fusion says 12 seconds with a straight plunge entry. Perhaps you can provide more details for further investigation - CAM program, pic of the tool path, any safe distances, etc.?


Hey Tom,
I’m using carbide create.
Looks like a pocketing operation is the best I can do for now.
The “default” tool specs are mostly what I was using, kinda thinking I should be able to pocket down more than 3mm per pass as I think it will machine out the 6.3mm (1/4") hole then finish with the step over to 8mm.
I ran it through an online simulator & it looks like after every pass, it’s retracting up to the safe distance above the cut (around 6mm) then going back in for the next pass.
Do you think it would be ok to increase the plunge depth to say 6mm per pass?

I would not increase the plunge depth for a straight plunge. Flat end mills are not designed for those types of operations - you would essentially be drilling with a flat endmill. If you can helix into the pocket it might work with a deeper plunge since you are not really digging directly into the material, but I don’t think Carbide supports that. Maybe using a drill bit to remove some of the material, then you can pocket at 6mm without much issue. Also, reducing your safe distance to something very small or increasing the rapids speed - you can rapid at 150 (3800mm/min) or 200ipm (5000mm/min) without any problems.