Losing position(and mind) a little at a time

Hello All-

Been doing my best to work my machines problems out but this one kind of has me stumped.

I am radius profiling 2 sides a 2" thick piece in z with multiple passes in x stepping y over in .01 increments to obtain a smooth curve.

The problem i am having is that as the cutter works across y it isnt square to x.
The opposite end is parallel to it but it is out approx. .625 in 14" Granted that only works out to about .0002 per pass(3100 passes)...but i cant for the life of me figure out why its doing it or how to solve it.
I started in cv mode for speed, switched to exact stop mode-no difference
set my speed to half and accel to a crawl- no difference.

I could accept it being lost steps if it didnt do exactly the same thing every time, and it didnt cut a perfect parallelogram.


the code was generated from sketchup through freemill but it is a pretty basic program length aside.


ive cut the piece 3 times and the exact same problem every time.

Any suggestions would be greatly appreciated.

Dave

I had a similar problem at one time which turned out to be a slow optocoupler on the breakout board I was using. I did a lot of raster work, and every direction change it would lose a step.....resulting in some parallelogram type crapola, too.

It took a hell of a long time to figure out, and I never would have on my own. Steve Stallings from PMDX helped me out a bunch on that one......and it wasn't even one of his breakout boards. Very nice guy.

I replaced the BOB with a PMDX 122, and all was well for me.

I sold the machine to someone else, and a similar problem reared its ugly head after switching computers.

He eventually figured out he wasn't getting a very good pulse output via the parallel port on his computer and put in a smoothstepper to solve the issue.....which it did. I know quite a few people that have had this same trouble as well.

I wish you luck tracking it down.....it can sure be frustrating.

I have abandoned parallel port and am using KFLOP on everything now. Absolutely no troubles on several machines.....and one of them is a crazy accurate cylindrical grinder (StuderS35) that needs to periodically hold .00005" in diameter. Most often it only needs to hold .0002" or so......but KFLOP is always rock solid.

This may be exactly what I have been chasing for a while

I have several jobs that mill circle shapes

After cutting several circles the X axis will be out .005 and it keeps getting worse as the job goes on.

The X axis always goes out in the X+ direction

I have been having to stop, reset X to zero and then continue again

The Y and Z axis are always right on zero
It's not my motors, or driver boards
The X axis is a ball screw and there is no bearing slop

Len at Probotix suggested I uninstall Mach3 and then delete all the left over files in the Mach3 folder (except for the mach3Mill.xml and license file

Reboot and then re-install mach3

I am running back to back jobs (cutting air) to test it today.
After a bunch of repeating the same job that gave me fits before, the
X axis is out by .0104 and y is only out by .0006

So X is still creeping a bit but not as bad as it was

Still not happy with this result, but it is better than it was
I am not famailiar with other methods besides using the parallel port

Where can I read up on the different choices available?