Machsupport Forum

*****VIDEOS***** => *****VIDEOS***** => Topic started by: ChuckNNashville on August 08, 2012, 04:58:09 PM

Title: Z-axis problem on our drill
Post by: ChuckNNashville on August 08, 2012, 04:58:09 PM
http://www.youtube.com/watch?v=gk47iDD1g3E&feature=g-upl (http://www.youtube.com/watch?v=gk47iDD1g3E&feature=g-upl)

We are having an issue with our drill.  It will run the .mmg file just fine, but over time the Z-axis on the drill starts to go higher and higher which causes the drill-bit to eventually not even touch the slab of wax in which we are trying to drill into.  Any ideas on how to fix it?
Title: Re: Z-axis problem on our drill
Post by: ChuckNNashville on August 08, 2012, 05:20:01 PM
This is coming back to the drill at the end of the program it was running:
http://www.youtube.com/watch?v=jMUbNbGIb5s&feature=g-upl (http://www.youtube.com/watch?v=jMUbNbGIb5s&feature=g-upl)
Title: Re: Z-axis problem on our drill
Post by: RICH on August 08, 2012, 05:34:49 PM
Try lowering your velocity and acceleration as there are small moves and you are / may be missing steps even though you don't hear the motor skipping.
I assume your code is correct.
RICH
Title: Re: Z-axis problem on our drill
Post by: ChuckNNashville on August 08, 2012, 05:39:38 PM
This code runs fine on my other mill.  I'll make those adjustments now and see if that helps.  Thanks.
Title: Re: Z-axis problem on our drill
Post by: RICH on August 08, 2012, 05:46:22 PM
Not all mills are alike. Is the other mill an exact duplicate of the one not machining correctly?
RICH
Title: Re: Z-axis problem on our drill
Post by: ChuckNNashville on August 08, 2012, 06:19:17 PM
No.  The other mill is not a duplicate.  I lowered the velocity and acceleration to around 50% and still had the same problem.  This mill is brand new and my other one is 10 years old.  My other mill is a Model master and the g-code is a .mmg file.  I've tried about a dozen different g-code formats on this new machine and still get the same problem.
Title: Re: Z-axis problem on our drill
Post by: RICH on August 08, 2012, 07:04:00 PM
Is the Z motor getting hot to the touch after the 15 minutes run time?

Did you lower the velocity and accel in the program  or did you just lower them in config.  
What i was wanting was for the program to be run at say 50 of current values and that includes any rapid moves at a lower velocity.
So you need to do both.

I am assuming that everthing is tight, like the couplings or pulleys. If you run very slow you should not have a problem with missing steps,
one woud think......  
RICH

RICH
Title: Re: Z-axis problem on our drill
Post by: ChuckNNashville on August 08, 2012, 09:06:49 PM
I lowered them in the config.  How do I do it in the program?
Title: Re: Z-axis problem on our drill
Post by: ChuckNNashville on August 09, 2012, 03:08:29 PM
http://www.youtube.com/watch?v=cQaTqW1Ki_I&feature=g-upl (http://www.youtube.com/watch?v=cQaTqW1Ki_I&feature=g-upl)

Do you think it might have something to do with our DeepGroove control box?
Title: Re: Z-axis problem on our drill
Post by: RICH on August 09, 2012, 06:30:30 PM
I think it is an inadequate motor....can't do the acceleration and velocities in the time frame being requested of it.
Power to raise the Z axis + power to accelerate ( change in velocity with respect to time) + power to machine ( in this case wax so negliable) + some extra say 20% = total required
Pulse frequency can also enter into this.

So if one slows everything down the system should respond and not skip. Where the reliability operating point is can only be found by doing some testing.

RICH


Title: Re: Z-axis problem on our drill
Post by: ChuckNNashville on August 10, 2012, 05:26:07 PM
Rich,
       We reloaded the software onto a new PC and the problem with skipping steps has been eliminated.  The g-code is now cutting the parts on the x and y axis's, and the z is mostly working except, on each pass the z raises slightly so by the end of the cut, the cutting tip is way up in the air.  It's as if the x axis on the mill is at about a 30% angle.  Is there a setting where I can tell mach 3 where '0' on the z axis is at more than one point of the cutting table?
Title: Re: Z-axis problem on our drill
Post by: RICH on August 10, 2012, 07:51:44 PM
 Is there a setting where I can tell mach 3 where '0' on the z axis is at more than one point of the cutting table?
Not that I know of.

You say that the problem of missing steps was corrected yet the Z is still not holding to position. ???
 How about swapping one of the other drives to run the Z and see if the problem is drive related.
RICH
Title: Re: Z-axis problem on our drill
Post by: ostie01 on September 05, 2012, 08:27:42 PM
I would thing that you have something loose in the mill, like a loose coupling from Z motor to the screw.

When you home the Z axis after that, what happen?

Just guessing.

Jeff
Title: Re: Z-axis problem on our drill
Post by: ChuckNNashville on September 05, 2012, 09:59:58 PM
problem fixed.  turns out it was a bad controller board in our system.  put in a new one and the problem went away.  thanks for the help.