Jerky movement
Posted: Fri Jul 25, 2025 7:23 am
Hi all,
I'm new here, and new to CNC, and new to any type of milling. Cue lots of broken cutters, etc, I'm sure.
I converted an old Bridgeport mill to CNC using Acorn and Centroid CNC12. I created some models in fusion. I created tool paths with advice from a few people and today I have made my first basic part (just an odd shaped block with some holes). I have done the first 2 operations which are clearing from top, flipping the stock, re-probing and clearing the bottom. It has gone very well. The part is within the desired tolerance with a reasonable finish despite very little dialling in.
However, I notice that the mill movement is slightly jerky, feeding a little bit, stopping, feeding again in ~0.5 second pulses. If I do a dry run with no stock the jerking stops.
I am using very cautious feed rates and step overs at the moment (100-200mm/min and 1.2mm step over with 5mm step downs. The stock is ally and I'm using a 12mm 3 flute cutter.
My acceleration was set to 0.5, tried 0.3 and it was worse. 0.6 seems about the same and if I try to set it any slower Centroid CNC says this is atypical and suggests I don't.
Can anyone offer any advice or insight?
Thanks in advance.
I'm new here, and new to CNC, and new to any type of milling. Cue lots of broken cutters, etc, I'm sure.
I converted an old Bridgeport mill to CNC using Acorn and Centroid CNC12. I created some models in fusion. I created tool paths with advice from a few people and today I have made my first basic part (just an odd shaped block with some holes). I have done the first 2 operations which are clearing from top, flipping the stock, re-probing and clearing the bottom. It has gone very well. The part is within the desired tolerance with a reasonable finish despite very little dialling in.
However, I notice that the mill movement is slightly jerky, feeding a little bit, stopping, feeding again in ~0.5 second pulses. If I do a dry run with no stock the jerking stops.
I am using very cautious feed rates and step overs at the moment (100-200mm/min and 1.2mm step over with 5mm step downs. The stock is ally and I'm using a 12mm 3 flute cutter.
My acceleration was set to 0.5, tried 0.3 and it was worse. 0.6 seems about the same and if I try to set it any slower Centroid CNC says this is atypical and suggests I don't.
Can anyone offer any advice or insight?
Thanks in advance.