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Author Topic: Unwanted datum shift in x axis  (Read 12470 times)

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Offline Tweakie.CNC

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Re: Unwanted datum shift in x axis
« Reply #10 on: May 06, 2013, 07:41:43 AM »
Hi Dave,

Your GCode appears OK with all 4 passes exactly the same.

As you are getting errors then I think the problem lies with your machine. You could be loosing steps, perhaps as a result of electrical noise or possibly tightness or binding of your axis linear bearings or lead-screws ?

Are your stepper motors running hot ?

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Unwanted datum shift in x axis
« Reply #11 on: May 06, 2013, 07:45:30 AM »
Hi

Yes all motors are getting pretty warm and after alot of runs nearly too hot to touch. When the machine is off the hand wheels on the motors allow you to move the axis with ease. Is there any other checks I can do?

Offline Tweakie.CNC

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Re: Unwanted datum shift in x axis
« Reply #12 on: May 06, 2013, 08:18:55 AM »
Dave,

With hobby machines the steppers should run warm to the touch but not too hot that you cannot keep your hand on them comfortably after a few hours of running. Perhaps reducing the drive current would help.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Unwanted datum shift in x axis
« Reply #13 on: May 06, 2013, 08:22:03 AM »
Excuse me being a newbie but how do I reduce the drive current lol. I tuned the motors down to 1500 max velocity test n got the accuracy better but frustrating to have to slow the mill

Offline Tweakie.CNC

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Re: Unwanted datum shift in x axis
« Reply #14 on: May 06, 2013, 11:01:16 AM »
Quote
Excuse me being a newbie but how do I reduce the drive current lol.

That is a function of your driver board - you would need to check your manufacturers instruction manual for how to set motor current.

What driver do you have ?

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Unwanted datum shift in x axis
« Reply #15 on: May 06, 2013, 11:06:18 AM »
hi, thanks for another reply. i havent got a clue sorry. its the one that came with the machine in the control box?

http://www.ebay.co.uk/itm/181091373085

is the ebay listing any use?

Offline Tweakie.CNC

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Re: Unwanted datum shift in x axis
« Reply #16 on: May 06, 2013, 11:56:15 AM »
That’s not any help so looks like you will have to leave the motors running hot until you can get some further information.

Something else you may wish to check…

In the Mach3 folder is ‘DriverTest.exe’ – run it and see if the result is a nice straight line.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Unwanted datum shift in x axis
« Reply #17 on: May 06, 2013, 12:02:37 PM »
hi,

i ran that test today also and it said that it was excellent in the green bar, only a very very tiny spikes

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Re: Unwanted datum shift in x axis
« Reply #18 on: May 06, 2013, 12:15:18 PM »
Tiny spikes are OK so it is unlikely to be a PC related issue.

Looks like I have just about exhausted my ideas on this one for the moment, sorry.  :'(

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Unwanted datum shift in x axis
« Reply #19 on: May 06, 2013, 12:19:19 PM »
Thank you for your repeated help. I have also just run shearline mode as suggested by Scott at Mach support at a low feed (200) it's ok but anything higher and problem returns. I am now running in demo mode a licence was a pirate copy

Many thanks

Dave