My 3040 has been losing z on some jobs and I did not know

My 3040 has been losing z on some jobs and I did not know why. Took apart the spindle setup and found the problem was some mount holes that were off. I hacked a solution to test and sure enough it runs fine now so I will have to redrill the holes to get it right. It worked most of the time but got worse over time.

Closeup of geometric pattern, one pass test, workout of Z axis.
missing/deleted image from Google+

That looks really good. What software do you use to generate the gcode?

Do you have a photo of the mount holes to explain the situation better?

Wow, Looks really good.

Check your acceleration setting on the z axis. To high and you can loose some steps.

@Ron_Hunn you did read the part “found the problem was some mount holes that were off. I hacked a solution to test and sure enough it runs fine now” ?

@andrea_buono , I’m using ArtCAM to Chilipeppr but Chilipeppr can’t handle large files so I’m going to have to switch back to Mach3 to do larger pieces. :frowning:

@Ron_Hunn , YES! I found that out for sure and dropped the z rate well below the x and y and have to really watch the feedrate. That’s why I was confused that it still happened on the same file at times. The z was always off with uneven friction due to off center mount of the motor that got worse over time.

@Marcus_Wolschon , I’ll take some shots when I mill new holes. It was obvious once I got the screws out that it was off. Looks kinda like they flipped the template, which should have been symmetric so it should not matter, because the plate fits perfectly when I flipped it over, which was my hack. This is NOT the ball screw version which I suspect would be better.