Feedrate randomly changing? AXBB-e

[crjohnson]

Hi guys,
I have been doing a bunch of boring operations lately , multiple holes on a PCD etc. Some of these holes have been with 3 or 4mm endmills (which I have little experience with) so have been manually slowing down the feedrate on the UCCNC screen.

I few times now I have seen the feedrate jump up to a much higher rate (maybe the default 1000mm/min?) when approx. half-way down a hole. When I hear the change I quickly press the overide up or down and it returns to what I had it set to before jumping.

Strange thing is that the feedrate shown does not change, but the machine running faster? I have looked through the code from fusion 360 and can never seen any line telling the machine to change, so I am wondering if it is a UCCNC thing?

[ger21]

My guess is that you have some rapid moves in there that are causing what you are seeing.

[crjohnson]

Hi Gerry,

As far as I can see there is a G3 at the start of each hole and a G1 at the end. But there was a definate change in feed rate during the boring operation. Each hole was at least 5mm deep, on another part they were 17mm, and the same thing happened.

The standard feed rate on my machine and F360 is 1000mm/min, I had this overidden to as low as 150mm/min so could hear exactly when it changed.

Edit: I'm running 1.2113 version and a HB04-4 USB plug-in pendant. No idea if this could be causing it? Next time I might try to run without the pendant plugged in?