[David57]

I have been running a diy cnc machine for several months... Lately i had problems with missing steps it seems... I am using MACH3.. I am cutting metal with a router setup.. problem is when it gets to my last inside cut there is a stall and you can hear it chatter or jumping.. for better words.. and the cut is off.. so i am assuming i am losing steps at that point... when it goes to cut the outside the cut is off too... I am running my fro at 200 just to speed up the cuts... and it doesn't do it on all my cuts it can cut several items out and then it can mess up the next couple at the exact spot (last inside cut)... any ideas anyone??

[ger21]

There's a known issue with Mach3 and running at high FRO values. Try doubling your feedrate in the g-code, and leaving the FRO at 100%.

[David57]

Will give that a try.. thank you

[David57]

I reduced my fro to 100 where it is normally at and i still have the same problem of the last inside cut i loose steps... so i tried it again and set my fro to 20 for the last cut and it did fine.. .but i hate to have to watch for the last inside cut and reduce the fro every time.. anyone else have this problem or know of any fixes??

[ger21]

Some people run into a bug where Mach3 ignores the acceleration settings in some cases, and tries to accelerate too fast. You may be seeing this, but I can't say for sure.

[bhurts]

It would be easy to just change the feedrate in the problem areas in the actual g-code. Then you don't have to watch but it will still slow down.

Ben

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[David57]

I have also noticed that it happens with either axis x or y.. it is just the last cut on my inside cuts that there seems to be that lag.. I was wondering if a short to either of my x or y driver motors could cause this problem.. still looking for any help.. thx