[stevieboy]

On a BMC 20 with max 3 control.

I've been doing a run of aluminium parts that were programmed offline in Cad-Cam using a high speed machining routine. In the software the feedrate was set to 2000mm/min for cutting and 4000mm/min for transitional moves in between cuts, spindle speed was 5500rpm. On the machine the chord error was set to 0.000.

I got about half way through the roughing process with a 25mm cutter and it stopped dead with this message on the screen.

"Motion Control Queue Runout Detected On X Y Z Axis".

I figured I was trying to run it too fast so I dropped the feedrate down to 1500 for cutting and 3000 for in between cuts. The chord error was changed to 0.003. I ran it again and it stopped in exactly the same place. The only thing that cured it was putting an extra 1mm on the depth of cut as this changed the path slightly.

The strange thing is I had already done 5 parts without any problem. The sixth part was put on over lunch and when I came back it had stopped. Never does it when you're there.

Any ideas what might have caused this problem. I know the machine's old and it does keep having these little tantrums but if I can avoid them it helps.

[bloke]

It could be caused by a slight axis balance offset that had crept in as the back cabinet with the drives in warmed up during the day. If it does it again, open the back doors and try running it again after ten minutes.

[stevieboy]

Ok, I'll give that a try. Must admit, I'd run it hard for at least 6 hours non stop with every tool running at 5500rpm. Even had a problem with the ATC saying it was missaligned. What I would for a new one.

Cheers Bloke.

[stevieboy]

Starting to have this problem more frequently now. It did it today on the first job that I ran, so the machine was still cold. Any more ideas?