Feedrate real-time increase

So newish to the community and haven’t seen this come up before. I’ve had some issues with a faulty cable and z limit switch last week. I’ve had some issues coming up over and over but didn’t know if this was correlated. So I only see this issue when I increase feed rate dynamically during a job in carbide motion. If I let it run at 100 percent it’s fine.

I had a larger job estimated 3 hours and about 15 minutes into job I hit increase up about 30-40%. After a couple passes my Z axis got out of whack. It jumped up about 3-5 mm but continued to run but never moving up/down on the z axis. I tried pausing job then unpausing and it just stayed locked up in motion and I had to hard reboot machine reinitialized machine and it seemed fine. Z limit appeared to be detecting properly while holding wrench under it. My pc is a newer machine and runs very smooth that runs motion. It seems like the program or the controller got bogged down it being a larger job. Any insight is helpful. Thanks ahead. Machine is a shapeoko 4 XXL. I’ll have to confirm sw version in another post when I get back to machine but it was newest a month ago.

Also I didn’t know if it was a best practice to set these what you know runs good and just let it run at 100 or do a lot of people do the button to increase in a job. Seen some YT videos where people were pushing this upwards of 180%. Just wanted to make sure I was doing things the correct and efficient way,

When you increase the feed rate you also need to increase the speed so as to maintain the chipload.

Extensive discussion at:


with a spreadsheet for this at:

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.