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Author Topic: Missing steps at 10 ipm? Taig, Mach3, Xylotex  (Read 28839 times)

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Missing steps at 10 ipm? Taig, Mach3, Xylotex
« on: March 02, 2008, 08:58:40 PM »
First post here.  I've had a Taig CNC for a couple years now, never got it working really well.  Just started to work with it again hoping to get it running.  Been following Mach since Mach1, using Mach3.

Running Mach on a 1.5ghz Pentium 4 machine, 640mb ram.  The cpu has been overclocked from 1ghz to 1.5ghz.  The Windows XP installation is not very old, though several programs have been installed and uninstalled, etc.  If I have to, I suppose I could re-install it, again.

Here's the issue, I wrote a little program that goes
F10
G90
G1 X2 Y1 Z1
G1 X1 Y.5 Z.5
G1 X3 Y1.5 Z1.5
G1 X2 Y1 Z1
.....
G0 X0 Y0 Z0

I took a digital camera video so you could see the movement and hear the steppers.  I sounds like they're losing steps, at 10 ipm.  I did a FRO 10%, and it sounds the same at 1 ipm.  I can see the motors stutter, all 3 axes do it.  Mach3 is running at 25,000hz, it did it at 35,000hz too.  Step pulse is 1, Dir pulse is 0.

http://www.youtube.com/watch?v=BVW-lYR9Yyg

Does anyone have an idea what I need to do?  Is it the computer?  Setup/motor tuning?

Thanks,
Monte

Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #1 on: March 02, 2008, 09:32:28 PM »
Hello Monte,
Have you verified that you have NO undue mechanical loads on the motors ?
Are the ways free and well lubed ? Screws, nuts and bearings clean, lubed and free ?
You mentioned that it had been idle for some time. (I get gummy when I do that)
You might disconnect the motor couplings or remove the belts and see if the motors miss any steps with no load on them.
Just a possibility.
Good luck,
RC
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #2 on: March 02, 2008, 10:15:58 PM »
>Hello Monte,
>Have you verified that you have NO undue mechanical loads on the motors ?
>Are the ways free and well lubed ? Screws, nuts and bearings clean, lubed and free ?

No, but I think it's fine mechanically.  It's lubed and clean.

>You mentioned that it had been idle for some time. (I get gummy when I do that)
>You might disconnect the motor couplings or remove the belts and see if the motors miss any steps with no load on them.

I guess I could try that.  It's a hassle, but I'll give it a go.

One thing else, it's inconsistent.  It's running at 5 ipm right now.  It started out fine, but it's starting to miss steps again as the program runs.

Monte
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #3 on: March 02, 2008, 10:30:02 PM »
Just took all the steppers off and set them on the table, it still does it.

Monte
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #4 on: March 02, 2008, 10:37:14 PM »
It may very well be an electrical issue as all 3 axes are doing it. But I would make absolutely sure that there is nothing wrong mechanically.
But that's just me. I'm more of a mechanic than electrician.
Good luck Monte,
RC

Man, you're QUICK !
Well......that shoots my theory in the arse.
I'm sure there is someone on this forum that can help here.
Regards,
RC
« Last Edit: March 02, 2008, 10:45:37 PM by Overloaded »
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #5 on: March 02, 2008, 10:45:08 PM »
It may very well be an electrical issue as all 3 axes are doing it. But I would make absolutely sure that there is nothing wrong mechanically.
But that's just me. I'm more of a mechanic than electrician.
Good luck Monte,
RC

Man, you're QUICK !
Well......that shoots my thoery in the arse.
I'm sure there is someone on this forum that can help here.
Regards,
RC

The table and headstock is fine mechanically.  Loosed the leadscrews and moved everything around by hand, slides fine.

Monte
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #6 on: March 02, 2008, 10:51:08 PM »
Monte, one thing I've seen numerous times here is the mention of keepingĀ  the signal wiring clear of higher voltage wires.
Picking up "noise" can cause problems.
I assume you are aware of this though.
RC
« Last Edit: March 02, 2008, 11:01:21 PM by Overloaded »
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #7 on: March 02, 2008, 11:40:39 PM »
Monte, one thing I've seen numerous times here is the mention of keeping  the signal wiring clear of higher voltage wires.
Picking up "noise" can cause problems.
I assume you are aware of this though.
RC

Yeah, I'm aware of that.  I think it's clear in that regard.

If (motors still loose on the table) I turn the motor velocity all the way up and do a continuous jog they'll not run smoothly either.  It actually sets up a regular noise pattern, sort of like dit dit ditty ditty dit dit, dit dit ditty ditty dit dit, dit dit ditty ditty dit dit, etc.  Sort of hard to describe, but my camera batteries are both dead so I can't post another video.  All 3 axes will do it, it's the same pattern for each.  They'll all sync if I hit the cursor keys the right way.

Monte
Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #8 on: March 03, 2008, 01:09:44 AM »
Here's a video of one motor on the table.  Listen to the audio pattern that gets going.  I'm doing a continuous jog with the keyboard.  You can hear when I started up the other 2 motors for a short time in the middle of the video.  I can feel the motor make a little jerk that matches the sound pattern.  Missing steps? Computer problem?

http://www.youtube.com/watch?v=DZUrAlST1kA

Thanks,
Monte

Offline Graham Waterworth

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Re: Missing steps at 10 ipm? Taig, Mach3, Xylotex
« Reply #9 on: March 03, 2008, 03:19:08 AM »
While you are running a NC program, bring up the task manager and see if the cpu usage increases at the same time as the motors change tone, it could be background tasks grabbing the cpu.

Graham.
America gave us powered flight, England the steam train and Germany the car.  Who invented the first boat?