[drcko]

I have a Next Wave Automation Shark Pro and am beginning to regret it. I have used the machine with no problems for over 3 years and lately it has begun to give problems with the Z axis. First, it will only raise and lower using the 'slow' in VCarve Pro. With 'medium' or 'fast' raise/lower option by tapping the Z+/- on the computer. I've contacted NWA several times regarding several issues, but am frustrated by their lack of customer service.
Has anyone had this problem regarding the Z axis?

[zeox]

Hi,
I've encountered such a problem, when switching my software for toolpath generating.
My first ever attempts at router milling had toolpaths generated by all sorts of free softwares, and there was no problem.
Next I got access to a workstation with Inventor HSM 2015. So the first time I ran G-Code generated by Inventor, my Z-axis plunged deep down into the material and even the collet nut went in before I was able to stop it. This happened a couple of times at the beginning and end of each operation.

Turned out these are two lines with G28 code, which tries to home the spindle at machine zero, which if not properly defined can be well below your workpiece
So, check your G-code and look for G28 commands in the beginning and end of the code. Get rid of those.

Also the software that generates your toolpaths should have an option to not include G28 commands in the code it generates.

I hope this works for you.

Edit: If you haven't changed the software for toolpath generation, it might be that you somehow changed your machine's zero point. This would explain why G28 code didn't create problems before, but has started to do it now.

[drcko]

Thanks for responding.
Unfortunately, I don't think this is my problem. It has happened recently on old files that I have run successfully, many times. I'm using all the same software and have made no changes to the G code. The bit just wants to keep going south. Again, when manually adjusting the Z, it will only raise/lower smoothly using the slow option. When trying to use either the medium or fast raise/lower option, it will only move a small distance at a time by tapping key quickly. Have you had similar problems as stated here?

[awerby]

Have you checked for mechanical problems? If it's having trouble going up and down, it could be that the slides or screw has come out of alignment, or a coupler has come loose. Stepper motors rarely fail in this way (unless you've disassembled them) so it's likely to be the mechanicals or the driver that's gone bad. If you swap the leads from the axis that's failing and run them to another motor (turning everything off first and letting the caps drain before unhooking anything), what happens? If a known good driver behaves the same way when hooked to your Z axis, that would tend to confirm the mechanical hypothesis.

[drcko]

Hello and thanks!
I switched the Z and Y cables which resulted in the Y 'stuttering' in the jog mode (the same stepper motor). I dismantled the rig and set the motor on the table and checked the jog speeds. All three speeds worked fine. I further removed the screw and "guides," ran the screw up and down a few times with a screw gun and it went smoothly. I cleaned and lubricated everything and slapped it all back together. It jogged perfectly! I didn't see any breakages or flatness in the screw, so I'm not sure what caused all the problem. I ran it up and down a few times in various jog speeds with no problem. I haven't tried running a file yet, so stay tuned.

Thanks to awerby and zeox!

[zszabo]

Hi,

Here is my story:
http://www.cnczone.com/forums/chines...866-forum.html