Messages

1

General Mach Discussion / Re: Noob needing help. Z axis dropping as it cuts

« on: December 10, 2012, 05:48:08 AM »

Thanks for all the info everyone. I would like to be able to run at a little higher speed so it sounds like I've got some homework to do. Gonna compare the ups and downs (cost) of a more course lead screw and or a motor that supplies a speed-torque curve in its documentation and see if its feasible for me. Thanks again.

James

2

General Mach Discussion / Re: Noob needing help. Z axis dropping as it cuts

« on: December 08, 2012, 11:25:36 PM »

Well lowering the axis velocities and feedrate seemed to rectify the issue. I have cut one complete pattern without any problems and am half way through a second. My follow up questions would be what is the specific cause? Is it a combination of limitations of software and mechanics or by upgrading the z axis motor and driver will it respond better to a higher feedrate and velocity? I am currently using 425 oz-in stepping motor and a 3.0Amp 24-40 Volts driver.

3

General Mach Discussion / Re: Noob needing help. Z axis dropping as it cuts

« on: December 07, 2012, 10:42:57 PM »

Thanks for the suggestion Rich. Since this is all a new experience I just wanna make sure I'm following correctly. I will try decreasing the motor velocity and acceleration by half in the motor tuning parameters of mach and then regenerate the g-code with a feed rate of half at the rate at which the current one is. I won't be able to run this till tomorrow since it will be over a six hour run with the lower feed rate, but will get back to you as soon as I have completed the test.
James

4

General Mach Discussion / Noob needing help. Z axis dropping as it cuts

« on: December 07, 2012, 06:03:30 PM »

Hey everyone. New to all this and I tried a couple searches and nothing seemed to pinpoint my issue. Additionally I am unsure exactly what is causing the issue and therefor don't have concrete terms to search. Hoping someone might be able to point me in the right direction.

First I'll start with the issue. I have a 9.875 x 9.875 pattern that I am attempting to cut. At different points, on different attempts, it seems like the z axis is dropping and creates a downhill slope.





I have gone through a couple guides and believe I have everything setup correctly and that nothing is mechanically loose or slipping. When testing the z axis with a dial indicator it repeatedly returns to zero without an issue cycling between .75 and 0. At first I thought perhaps the bit was slipping but I have since marked the bit before cutting and can verify that it is not coming out of the collet while cutting. I have done a few test cuts on smaller patterns and don't have the same issue.

After posting this I'm planning on swapping the z and x axis driver to see if perhaps the problem follows the driver but would rather not chase this issue all over the place if anyone might know the cause right off hand.

Thanks for any help.