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Author Topic: Why does my z lift incrimently more after every cut.  (Read 2613 times)

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Why does my z lift incrimently more after every cut.
« on: January 28, 2013, 07:33:15 PM »
Every time I cut
  My z lifts to a certain height and cuts, but after the cut, it moves to the next starting point, and lifts even more...my z never stays zeroed where I zero it, why?

Offline Chaoticone

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Re: Why does my z lift incrimently more after every cut.
« Reply #1 on: January 28, 2013, 08:11:36 PM »
Sounds like its skipping steps somewhere. 

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Why does my z lift incrimently more after every cut.
« Reply #2 on: January 29, 2013, 07:46:01 AM »
Try running it without cutting any material and see if it still has the problem.

If it works ok like this then you may need to look at a bigger Z motor or maybe some gear reduction to increase your torque.

Also check your tool is sharp, Try increasing RPM or reduce feed rate for the Z moves.

Cheers Allan.
Re: Why does my z lift incrimently more after every cut.
« Reply #3 on: January 29, 2013, 08:16:41 AM »
I was thinking last night, and it it hit me,
  I tested the steps/per on the z, but not with a particularly accurate measuring tool.
The dro stays consistant, but the torch just keeps climbing....
  I'm going to test with a dial indicator today to see if I'm as accurate as I should be.  It just seems like there was a setting somewhere that was affecting this, but now I'm wondering if there is miscommunication somewhere.
Re: Why does my z lift incrimently more after every cut.
« Reply #4 on: January 29, 2013, 11:14:27 AM »
I once had this issue.  For me, turns out the motor coupling was loose by a loose shaft screw.
Re: Why does my z lift incrimently more after every cut.
« Reply #5 on: January 29, 2013, 11:55:18 AM »
I had one of the screws come loose a while ago,
  I could check it again.
  I went and got a dial indicator and am going to make sure it's measured perfectly.
 I'm fairly certain this could be an issue. Seeing that the computer thinks the tool is where it should be.
  When I measured my steps/inch it was only a rough measurement, and am guessing it's gotta be a pretty accurate measurement to be able to make accurate adjustments.

Offline Chaoticone

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Re: Why does my z lift incrimently more after every cut.
« Reply #6 on: January 29, 2013, 02:31:28 PM »
I would do the math to arrive at the steps per inch.  That way you know it is correct and this number never changes unless you change something mechanical such as a gear or pulley or possibly a microstepping option on the drive. It is locked in by components and not used for tuneing.  Just measuring does not allow for skipped steps and such.  It could be skipping steps when you measure.  Here are a couple of links that may help.

A steps per calculator.
http://www.machsupport.com/forum/index.php/topic,16315.msg110286.html#msg110286

An explination of the math involved.
http://www.machsupport.com/forum/index.php/topic,12512.0.html

Brett

;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!