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Author Topic: machine is out by .5mm in x and y axis even after setup  (Read 1780 times)

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machine is out by .5mm in x and y axis even after setup
« on: March 02, 2017, 04:43:42 AM »
Hi guys
I need help please, im going round in circles.

I have recently built a 1500 x 1000 v slot belt driven 3 axis machine.
I have used the setup function to set the steps and when I tell the axis to move 10mm it does, so I enter that value. it matches on the dro too.

now when I load code to run programme I want to machine a rectangle of 30mm x 10mm and when its machined it both dimensions are off by .5mm

what am I doing wrong?

I am using nema 23 stepper motors 1.8 and I am getting lost

any help would be fantastic

Offline Davek0974

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Re: machine is out by .5mm in x and y axis even after setup
« Reply #1 on: March 02, 2017, 05:14:21 AM »
Did you only set the the steps per over a 10mm distance ??

I would try again using a good steel rule or measure over a long distance say 900mm or more.

Unless it is losing steps but too early to show that i think, it must be calibrated 100% first.

Is this wood router?

Maybe also the tool is 0.25mm off-size, depends how good the tool is but is possible
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: machine is out by .5mm in x and y axis even after setup
« Reply #2 on: March 02, 2017, 08:02:06 AM »
hi thanks for you reply.
yes I only did that over 10mm.
I was using a Digital gauge to measure 10mm but like you say perhaps I need to do it over a further distance.
it is a wood router. and the tools im using are very accurate in dimensions as they are actually from a metal cnc machine.

I also have issues when I power the machine up, the y axis judders in one direction when no jogging is pressed, it stops when I jog the x axis. doesn't do this during a programme.

I don't know where im going wrong and I have spent a small fortune getting this machine built

Offline Davek0974

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Re: machine is out by .5mm in x and y axis even after setup
« Reply #3 on: March 02, 2017, 08:13:18 AM »
Its always best to calibrate over the longest distance possible.

Does the axis just "thump" or does it keep moving??

If it thumps and stops thats pretty normal for stepper motors, if it keeps ,moving thats not right.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: machine is out by .5mm in x and y axis even after setup
« Reply #4 on: March 02, 2017, 08:22:44 AM »
it judders and doesn't stop until you press another axis button in jog.
my y axis has 2 motors connected to one driver but one motor in the opposite direction. do you think this may be an issue? does each motor need an independent driver?
if so how would I setup another driver on my control board?
I can get some photos tonight of the electronics and settings
Re: machine is out by .5mm in x and y axis even after setup
« Reply #5 on: March 02, 2017, 08:38:06 AM »
I also don't know if my current settings are correct on my TB6600 driver
Im using these motors-2305HS280AW-265oz from ooznest

driver settings
1-off
2-on
3-off
4-off
5-off
6-on

Offline Davek0974

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Re: machine is out by .5mm in x and y axis even after setup
« Reply #6 on: March 02, 2017, 09:39:04 AM »
I would not connect two motors to one drive - just sounds like a bad idea *unless* the drive is specified as being capable - i do not know any that are.

What control board do you use - to slave properly you generally need a 4axis board *but* some boards can take two drives on one axis ok.

You would normally have a motor connected to each drive and each drive connected to the break-out board which is then connected to Mach3 and Mach3 is set as slave X&A or Y&A etc
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives
Re: machine is out by .5mm in x and y axis even after setup
« Reply #7 on: March 02, 2017, 09:46:06 AM »
Thanks

im using the 5 axis breakout board and TB6600 DRIVES, TRYING TO ADD A PICTURE ON HERE TO SHOW YOU. may have to buy another driver and slave it to A as you say
Re: machine is out by .5mm in x and y axis even after setup
« Reply #8 on: March 02, 2017, 09:52:41 AM »
https://www.youtube.com/watch?v=Mv8mCXMVKUo

this is my setup board and drivers
Re: machine is out by .5mm in x and y axis even after setup
« Reply #9 on: March 02, 2017, 10:25:50 AM »
I have ordered another driver and will slave it. will do the calibration over a longer distance and let you know if its any different. thanks for your help