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Offline Freff

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Wizard Inaccuracies
« on: September 11, 2008, 04:36:47 PM »
I have just started using Mach3 R2.63 (licensed) with the come with wizards. To get some experience I have started using the wizards, the Circle Cut to be a good starting element. All the settings I entered came out on the work piece Ok except the diameter.

No matter how many times I tried the diameter always come out different to the setting I entered. Not only that they are randomly different. I have tried the circular pocket and the results are the same, always the diameter.

I'm sure that I'm entering all the settings correctly, but I'm possibly missing something. Could someone please point me in the right direction, it's getting very frustrating.

Many thanks
Tony

Offline Hood

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Re: Wizard Inaccuracies
« Reply #1 on: September 11, 2008, 04:49:55 PM »
Have you checked to see that your steps per unit are set correctly and are giving you accurate distances, ie if you cmmand a G0X2 does it move the axis exactly 2 inch (remembering to zero the axis first ;)  )
Hood

Offline Freff

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Re: Wizard Inaccuracies
« Reply #2 on: September 11, 2008, 05:20:50 PM »
Hi Hood and thanks for your quick reply. I commanded G0X2 and the axis moved about 1mm. not 2".
If I run any other Gcodes for example ones I have created myself in Lcam eg. then they come out fine.

Offline Hood

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Re: Wizard Inaccuracies
« Reply #3 on: September 11, 2008, 05:23:18 PM »
ok so are you set up in metric units?
 Did you remember to zero the X axis before you  commanded the G0X2?

Hood

Offline Freff

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Re: Wizard Inaccuracies
« Reply #4 on: September 11, 2008, 05:27:34 PM »
Yes zero'd all axis.

Offline Hood

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Re: Wizard Inaccuracies
« Reply #5 on: September 11, 2008, 05:32:43 PM »
OK if it doesnt move the distance you have commanded then it seems you dont have your steps per unit set correctly.

 What type of motors do you have? If steppers are they 1.8 degree or 0.9 degree (200 or 400 steps per rev) If Servos what is the resolution of the encoders

What type of drives do you have and is there any microstepping set in them?

What is the pitch of your ballscrews?

Any gearing between motor and screw? if so what is the ratio?

Hood

Offline Freff

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Re: Wizard Inaccuracies
« Reply #6 on: September 11, 2008, 06:02:44 PM »
The motors are 200 step 1.8 degree steppers. FL60STH86STH (3Nm 23 frame stepper motor) (FL60STH86)

MSD542 microstepping driver set at 8 microstep, 1800 ustep/rev.

Lead screw is 6mm 24tpi no gearing.

Thanks for staying with this Hood.

Tony

Offline Hood

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Re: Wizard Inaccuracies
« Reply #7 on: September 11, 2008, 06:13:42 PM »
Not sure what you are meaning by 1800 u step per rev but anyway heres what your steps per unit should be
200 steps x 8 for micro steppingĀ  = 1,600 steps per rev of the motor, your leadscrew is 24 tpi so that is 24 turns to move 1 inch.
multiply the 24 turns by 1,600 steps per rev of motor and it gives you 38,400 steps per inch.
As you are set up in metric divide that number by 25.4 to get the steps per mm and it is 151.18110236220472440944881889764 steps per mm :)

Hood

Offline Freff

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Re: Wizard Inaccuracies
« Reply #8 on: September 11, 2008, 06:32:34 PM »
Sorry that 1800 was a typo it should have been 1600 as you state.
Do I now enter the 151, etc in the motor tuning at the steps per box, leavibf the acc & rev as they are.

Offline Hood

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Re: Wizard Inaccuracies
« Reply #9 on: September 11, 2008, 06:36:47 PM »
Yes enter that in the steps per box for each axis (presuming they are the same) and whether you will need to alter the Velocity and Acceleration will depend on what you had previously. If it was close then no you probably wont, if it was off by a bit then you may find you need to re-tune as you will maybe miss steps.
Hood