[Moretzmando]

First a background on my machine. I bought a used 6040 machine and trashed the electronics. I have individual Gecko drives, 60v power supplies, new bearings throughout, nema 24 455oz motors, stainless motor mounts and couplers(corvetteguy/Vince from YouTube), and have replaced my t track bed with a 3/4” thick ATP-5 plate. Everything has been torqued with a torque wrench and all wiring has been replaced with shielded cable and the ground wire grounded at on end, everything has been star point grounded. VFD is in a separate enclosure with an EMI filter. The entire out fit is enclosed and includes vacuum for table/fixtures, air compressor and mister, eve coolant for .8kw spindle(which has been grounded. I soldered every connection with aviator style connectors. I’m using Fusion 360 CAM/CAD. 300ETH, UCCNC software. I said all that to say this. I’ve tried my best to learn as much about CNC machines and CAM/CAD software as possible over the last several months. I’m now at the point of setting up my feeds and speeds for different bits, amd that’s were I need some advise. It almost doesn’t matter how small of a cut a take, or how slow the rpm of my spindle, or how fast my feed rate, 1/4” 2 flute upcut(Speed Tiger, Whiteside, Kodak), 1/8” single flute(HQ master, 1/8” double flute(HQmaster), doesn’t matter seems to always end up with the bit over heating. I’ve watched Winston Moy, Cutting it Close, among others on YouTube, to get an idea of speeds and feeds. I even subscribe to HSMadvisor and still nothing. I just ran a test on cutting slots in MDF with an 1/8” end mill. The HSMadvisor recommend a depth of 1x the diameter of the tool(0.1250) 18,000 rpm with a feed rate of 48.6 for a slot/pocket operation. I cut one 6” line=smoke. I tried lowering the rpm to 12,000 for the next line=smoke. 12,000 for the next line=smoke. Feed rate of 60in/min=smoke. 80in/min=smoke 100min=smoke 100in/min smoke. Seemed to be less smoke the faster the feed rate. Redone the test with 120in/min deepening the original first line amd it snapped the cutter right after it ramped into it. Last time I tested I tried 1” square pockets with the same results. Didn’t matter if I was using conventional pocketing or adaptive strategy. It’s driving me nuts! And I haven’t even started on 3/16 or 1/4 bits. What could be going on here? TIA

[ger21]

Make sure the spindle is not spinning backwards, which would be my first guess.

Fwiw, at 18,000 rpm, you should be able to cut MDF 1/8" deep at 300-350ipm no problem. 48"/min will burn up the bit.

[Moretzmando]

Make sure the spindle is not spinning backwards, which would be my first guess.

Fwiw, at 18,000 rpm, you should be able to cut MDF 1/8" deep at 300-350ipm no problem. 48"/min will burn up the bit.

That is too funny, right after posting this I was looking at my new 1/4” upcut bit, making sure I didn’t by downcut, bumped my spindle on Viola! spindle is turning backwards! Thanx so much! I’ll reply again after reversing the wires on my VFD. I feel like such an idiot, but also relief!!!!