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Re: BAD Monday! My router is not moving how far I tell it to...
« Reply #10 on: May 04, 2010, 05:28:18 PM »
Oh... okay, I know what that is... just didn't know wht it ws called. How do I post it without it taking up so much space here? Or should I just paste it into this window?

Chris

I got it! Here it is.
« Last Edit: May 04, 2010, 05:32:29 PM by chrisinestes »

Offline Hood

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Re: BAD Monday! My router is not moving how far I tell it to...
« Reply #11 on: May 04, 2010, 05:56:21 PM »
Bit curious, your steps per unit seem quite course, how are the axis driven, presume a rack of some sort as you have for example the X axis at 2035 steps per inch and your motors will be 2000 steps per rev so your axis must move almost 1 inch per motor rev

In the SS config I would reduce the Step Frequency to 32KHz for all axis, this probably wont make any difference but you never know. Reason to reduce is with your steps per unit and velocity in motor tuning the fastest axis (Y axis) is only requiring 12KHz.

Hood
Re: BAD Monday! My router is not moving how far I tell it to...
« Reply #12 on: May 04, 2010, 06:44:11 PM »
Bit curious, your steps per unit seem quite course, how are the axis driven, presume a rack of some sort as you have for example the X axis at 2035 steps per inch and your motors will be 2000 steps per rev so your axis must move almost 1 inch per motor rev

In the SS config I would reduce the Step Frequency to 32KHz for all axis, this probably wont make any difference but you never know. Reason to reduce is with your steps per unit and velocity in motor tuning the fastest axis (Y axis) is only requiring 12KHz.

Hood

All of the Axis' are driven through a gear & belt system. None are connected 1 to 1 to the steppers. I'll look in to the step frequency thing.

Thanks!
Chris

Offline Jeff_Birt

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Re: BAD Monday! My router is not moving how far I tell it to...
« Reply #13 on: May 05, 2010, 07:59:20 AM »
Hood, Chris's router is a quite interesting commercial built unit. The X-axis is driven by one humongous 950 oz-in (as I recall) stepper through a belt reduction, sent to both sides of the gantry with a cross shaft which has timing pulleys fixed to the ends that drive fixed (wide) timing belts. It pulls itself along the belt. Consequently the steps/unit is quite low but the big stepper has lots of torque at those low speeds.

Chris says the Y-axis was cutting long, he recalibrated the steps/unit for each axis with the Mach axis calibration tool and it is coming out quite close now. I'm anxious to see how things go when he gets his spindle remounted.
Happy machining , Jeff Birt
 

Offline Hood

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Re: BAD Monday! My router is not moving how far I tell it to...
« Reply #14 on: May 05, 2010, 09:58:55 AM »
Sounds interesting and likely accurate enough for a router.

Can a 950 ozin stepper be run from a G540? would have thought the current requirements would have been too much to use the full torque potential of the stepper.

Hood

Offline Jeff_Birt

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Re: BAD Monday! My router is not moving how far I tell it to...
« Reply #15 on: May 05, 2010, 10:39:38 AM »
Quote
Can a 950 ozin stepper be run from a G540? would have thought the current requirements would have been too much to use the full torque potential of the stepper.

That was my first reaction too, when Chris said that Gecko recommended a G540 to him. Then as I researched the original controller/stepper driver he had I realized that the G540 was heaps a lot better then the OEM stuff. As I recall the motor was already wired in series with a resulting current requirement that fell within the G540's range. You cannot get the maximum performance out of the stepper as if you could as if it were wired in parallel with a higher current driver or with a higher driving voltage but it does provide all the power needed for the application.

I just thought the design was interesting and a but unusual, but it seems to work well. Since we typically get all worked up about getting every last drop of performance out of a stepper motor it is kind of interesting to see a design that 'under drives' a large stepper to provide the power needed for the application with a more modest driver.
Happy machining , Jeff Birt
 

Offline Hood

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Re: BAD Monday! My router is not moving how far I tell it to...
« Reply #16 on: May 05, 2010, 10:42:30 AM »
Would be good to see some pics of it :)
Hood

Offline Jd

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Re: BAD Monday! My router is not moving how far I tell it to...
« Reply #17 on: May 05, 2010, 12:25:55 PM »
Chris I had a problem on my milling machine with a sudden ambient temperature change a couple of times, don't know if that helps, but I agree that checking your tuning is important, I found that checking on short moves is not as accurate as checking on repeated long moves, I also had a unexplained change in my .xml once and had to use a .xml backup from a couple of days back when things were good. Read your Mach3 manual about .xml's     JD 
Re: BAD Monday! My router is not moving how far I tell it to...
« Reply #18 on: May 05, 2010, 12:38:57 PM »
Hood,

Here's a couple pics of my machine with the covers off the gantry.