Z axis not consistent (missing steps?)
Posted: Tue Oct 04, 2022 2:33 pm
Hello all,
Let me start by thanking you all in advance for any help and also apologizing in advance for my significant lack of experience, knowledge and information.
So, I have an Acorn cnc table router ~4'x8'. I've dialed in the x and y axis pretty well so have little to no concern those are working fine.
The z axis on the other hand I have not been able to get working consistently/accurately.
To try and explain:
I have a simple program to cut a hole about 1 inch in diameter and about 1/4 inch deep via two depth cuts. The first time the program runs, it seems to run just fine. But if I change nothing, and run the program again, it will cut a deeper and deeper hole. Again the x and y axis fall in the exact same spots, but the z axis looses steps downwards.
For example (and some data to help maybe?). First cut the hole is .155 deep (which I know is not actually 1/4 inch, but I'm not concerned about that yet). Second cut (again, changing nothing, simply hitting run again after the program completes), and the hole is now .219 deep. Run it again, and the hole is now .250 deep. A 4th run and the depth of the hole is now .320 deep. Keep in mind the machine thinks it is going back to the false home I set it to go to after each run (+17.5522), but it is not actually going back to the same home position (again moving down incrementally; .126 away from the limit switch, then .175 away, then .200 away and finally .260 away).
One other bit that may be of some information. When I do the calculations to dial in the RPI, I can do the math for the x and y axis and the numbers dial in closer and closer to a pretty decent tolerance. But when I do that for the z axis, it seems to get closer and closer, then it goes way off. I'll work it some more and it will get closer an closer, then way off again. Sometimes it's way off + and other times it will be way off in the - direction. I can never really get it dialed in because of that, but I believe it's currently as close as I can get it.
I hope that's enough information to give you all some ideas on what to try next. I've been working on this on my own now for quite some time, but have no experience with acorn prior to this and very little assistance has made this quite challenging. Please let me know if you all have any clue.
Thank you again in advance!
DTucker
Let me start by thanking you all in advance for any help and also apologizing in advance for my significant lack of experience, knowledge and information.
So, I have an Acorn cnc table router ~4'x8'. I've dialed in the x and y axis pretty well so have little to no concern those are working fine.
The z axis on the other hand I have not been able to get working consistently/accurately.
To try and explain:
I have a simple program to cut a hole about 1 inch in diameter and about 1/4 inch deep via two depth cuts. The first time the program runs, it seems to run just fine. But if I change nothing, and run the program again, it will cut a deeper and deeper hole. Again the x and y axis fall in the exact same spots, but the z axis looses steps downwards.
For example (and some data to help maybe?). First cut the hole is .155 deep (which I know is not actually 1/4 inch, but I'm not concerned about that yet). Second cut (again, changing nothing, simply hitting run again after the program completes), and the hole is now .219 deep. Run it again, and the hole is now .250 deep. A 4th run and the depth of the hole is now .320 deep. Keep in mind the machine thinks it is going back to the false home I set it to go to after each run (+17.5522), but it is not actually going back to the same home position (again moving down incrementally; .126 away from the limit switch, then .175 away, then .200 away and finally .260 away).
One other bit that may be of some information. When I do the calculations to dial in the RPI, I can do the math for the x and y axis and the numbers dial in closer and closer to a pretty decent tolerance. But when I do that for the z axis, it seems to get closer and closer, then it goes way off. I'll work it some more and it will get closer an closer, then way off again. Sometimes it's way off + and other times it will be way off in the - direction. I can never really get it dialed in because of that, but I believe it's currently as close as I can get it.
I hope that's enough information to give you all some ideas on what to try next. I've been working on this on my own now for quite some time, but have no experience with acorn prior to this and very little assistance has made this quite challenging. Please let me know if you all have any clue.
Thank you again in advance!
DTucker