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Offline tarik

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question from beginner
« on: May 13, 2009, 08:59:57 AM »
  hi,
i run gcode on my machine, but it moves very very slowly.
i need to know if sth is wrong concerning motor tuning in mach3,or i have to change the values of feed and speed on my cam software??
plz can any one advice me concerning this.
thank you.

Offline Hood

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Re: question from beginner
« Reply #1 on: May 13, 2009, 09:10:33 AM »
depends what you have for the feedrates, if the codes says  F100 for example and it actually only moves at  50 then it will be your motor tuning or kernel that is to blame.
Hood

Offline tarik

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Re: question from beginner
« Reply #2 on: May 14, 2009, 06:01:04 PM »
if i do the calculation of my motors using SET STEPS PER UNIITS in the setting screen, will it work correctly?i mean nothing to worry about? or i need to do some calculations to set them correctly?

Offline Hood

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Re: question from beginner
« Reply #3 on: May 14, 2009, 06:06:09 PM »
It is best to do the calculations and enter the steps per unit manually as using the Set Steps Per Unit button will only ever be as good as you can measure.
Hood

Offline RICH

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Re: question from beginner
« Reply #4 on: May 14, 2009, 08:41:42 PM »
Maybe dreaming,
But i thought that there was a plugin or something were you can just put  steps per unit in verses actual distance wanted and it would calc the change in steps required to get there if it wasn't correct. You just input  the distance difference. Just needed to repeat a few times and it was quick and accurate. I remember Brian talking about it.  
RICH

Offline Hood

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Re: question from beginner
« Reply #5 on: May 15, 2009, 02:58:30 AM »
Rich that is the Set Steps Per Unit button on the Settings page (or Diagnostics page, I forget as I dont use the standard screen) but as said it will only ever be ass acuurate as your means of measuring axis travel.

Hood

Offline jimpinder

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Re: question from beginner
« Reply #6 on: May 15, 2009, 03:10:32 AM »
Just check which units you have set set up in, and which units you are runing in.

Check you GCode program for the F command, and see what speed you are expecting.

If you have got as far as running GCode, we must assume that you have set the machine up correctly i.e. your steps per unit etc are correct.
Go to motor tuning, and see what maximum speed you have set. I don't know what your machine is, or what speeds you are expecting, but the way to tune the motors is to start with a low figure and gradually up the spedd. Check this by jogging your axis. You will reach a point where the motor breaks down. Back the speed off until it resumes again ( and perhaps a little more for reliability ) and your maximum speed is set. Do the same now with the acceleration. Ensure that you SAVE each axis as you do this, or your machine will revert to the last setting as soon as you leave the page.

Have you set up in mm, and your cad/cam is writing a program in inches.In this case, you must ensure that there is a G20 (imperial) command at the beginning of the program - otherwise your machine will take all its movement in mm rather than inches - and move 25 times too slowly.

As Hood said, you must Calculate your steps per unit.for your axis. Most (stepper) motors are 200 steps per rev.Most drivers operate on micro steps, 8 or 10 perhaps - that is 2000 steps and if your leadscrew is, say, 10 turns per inch then this would be 20,000 steps per inch, If you have any step down gearing ( I have 3 to 1 on my steel lathe) then that puts the steps per unit up to 60,000 per inch. I have recently gone metric (with ball screws) with a 5mm pitch thread, so my steps (now per mm) are down to 1,200 per mm. This is the order of scale you should be looking at.
Not me driving the engine - I'm better looking.

Offline tarik

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Re: question from beginner
« Reply #7 on: May 15, 2009, 06:25:57 AM »
thank you for your help, thow i' still little bit confused :)
i'm gonna do some little tests to clarify this in my mind
thanks

Offline RICH

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Re: question from beginner
« Reply #8 on: May 15, 2009, 10:44:40 AM »
Thanks Hood,
Yep, it's on the Settings page in Mill only. Tried it out a few times  a "long" time ago and forgot where it was.
RICH