retrofitting a Proxon for coin die milling

Some people run the pi4b with a slower servo thread eg 2 ms or 1.5 Ms with mesa cards
run:
latency-histogram  --nobase --nobase 1000 --show
and share the screenshot here. the 4b is marginally OK but 126us is fine for a Mesa card at 1 ms servo thread.

mclien wrote:

ballscrews ar primary because the original threads in brass nuts have quite some deadway.

Just so you know, LinuxCNC has backlash compensation parameters. That said, I'm not real sure milling dies would go well with backlash. I used to have a diy CNC router with cheap ACME screws, running LinuxCNC + parport + microsteppers. I did more drilling than routering with it, drilling the thru-holes in home-brew PCBs. On that machine, backlash compensation was the ticket.

Here are the 2 screenshots of the Pi. One whithout anything but the Desktop running, one with glxgears running (window resized to about the double).

Pi5 might work better. But given that you have a 7i96 the Pi4 should work fine with the latency shown. (Just don't watch YouTube while milling)

See if you can add isolcpus=3 to your kernel boot file. I have done it on a pi but can't remember how
It should improve latency.

As rodw said, try to add isolcpus=3 or even isolcpus=2,3 in your /boot/firmware/cmdline.txt

Also, I did some tests with Remora over ethernet on a PI400 and you should follow rodw's video to adjust the ethernet connection to your mesa card.