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Author Topic: Is this a bug in LazyTurn?  (Read 10101 times)

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Re: Is this a bug in LazyTurn?
« Reply #10 on: November 02, 2009, 11:45:02 AM »
Rich / Bud,

I double checked.  Yes, I'm using the May 28 LT.

The Z-offset is at 0.1.  I don't remember if I put that in, but if I did it was a long time ago.  I haven't been doing anything to it for the last two weeks at least.  I haven't touched either the Z-offset pointer or stock location pointer on the ruler.  That's why it's a mystery to me, that the profile moves on the stock even though AutoCAD always shows the profile at the UCS origin.  This is not a showstopper.  I can work around it, now that I'm aware of it

My showstopper is:  I apparently have some hardware problems after all.  As I am cutting the profile, Z-axis stepper acts like it is briefly sticking or something, i.e., getting slightly offset.  I don't think the problem is mechanical.  I cut the Z-axis speed and acceleration in half and I'm still seeing the same problem.  I am suspicious of my Dell laptop.  I'm going to switch to a different platform, running a fresh install of Win2K, my favorite Windows version.

I'll be back after I get a handle on my hardware problems.

I must say, it is gratifying and reassuring to get the level of attention you guys are giving.  I saw this forum and this process before I chose Mach3, and this was a major factor in my decision to go with Mach3 instead of the alternatives.

Thanks!
Dave

Offline budman68

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Re: Is this a bug in LazyTurn?
« Reply #11 on: November 02, 2009, 11:49:35 AM »
Let us know how it goes, Dave, as the Dell laptops can definitely be "iffy" on whether or nor they work.

There's a thread floating around on this forum about Dells and I have a D600 and it works fine but I think the next model up (D610?) has serious voltage variances and creates havoc.

Good luck-
Dave
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Offline RICH

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Re: Is this a bug in LazyTurn?
« Reply #12 on: November 02, 2009, 03:15:44 PM »
My Dell latitude can only be used with a SmoothStepper and the same goes for the Dell Optiplex.
I think Dell's are just a poor choice with on board graphics. But That's just my opinion
The best thing i ever did was to have a PC put together.
RICH

Offline budman68

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Re: Is this a bug in LazyTurn?
« Reply #13 on: November 02, 2009, 03:48:07 PM »
Hi Rich, with the Dell OptiPlex, it really seems to depend on which form factor as well as some of those samller ones are basically laptops in a tiny size tower form.

I have a Dell OptiPlex GX260 which is a full size tower and workhorse  8)

Dave
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Offline RICH

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Re: Is this a bug in LazyTurn?
« Reply #14 on: November 02, 2009, 04:03:50 PM »
Hey Dave,
The Optiplex is great for everything and they were used at work for doing high end 3d design.
But for running my steppers via PP, it just plain sucks and never was able to get a good signal out of it no matter what was done or tried. Steppers sounded just like they were being hit with a mallet and limited to 8 IMP.  The SS was the only cure. What can i say!
RICH
Re: Is this a bug in LazyTurn?
« Reply #15 on: November 04, 2009, 03:04:18 PM »
Rich / Dave

I found my hardware problem.  It isn't the Dell laptop.  It's worse.  Apparently, I'm fighting a resonance in my Z-axis actuator.

I slowed the Z-axis *waaay* down and the problem went away.  Now I have to figure out how to identify the resonance and how to deal with it.  This is an area I have no experience in.  Can you point me to a recipe or tutorial on how to measure and compensate for resonance?  I'm hoping I don't have to do this by trial and error because that could take forever. 

Now, there's a Lovejoy-style coupler between the step motor and leadscrew.  I'm suspicious of the rubber spider between the two halves.  Seems to me that this could invite resonance problems.  Yes? No?  The leadscrew is almost 30" long and at least 1/2" dia., pretty massive.  And the stepper shaft is only 1/4" and is probably twisting under the torque and contributing also.  Would a larger stepper with a more robust shaft help?

Should I post this on a different part of the forum?

regards,
Dave   

Offline budman68

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Re: Is this a bug in LazyTurn?
« Reply #16 on: November 04, 2009, 03:23:30 PM »
Hi Dave,

yes, post this in the "General" area of the forum and you'll get more views that way. Somebody else would be better at helping you with this as this is not my area of expertise. As a matter of fact, I have NO area of expertise,  :D

Just a thought, have you tried switching motors and or couplings with another axis to try and narrow the problem down a bit?

Good luck,
Dave
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Offline RICH

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Re: Is this a bug in LazyTurn?
« Reply #17 on: November 04, 2009, 05:21:07 PM »
Dave,
Do re-post the problem as Budman suggests. Povide a description of the problem as best you can.
Give info on the ipm / velocity / accel your running. A picture of the axis which shows support,  how the motor is mounted,and a general shot of the machine  is worth a thousand words.
There is a difference between a motor resonance and mechanical resonance of a shaft and what occurs.
That should provide folks with basics to assist you.
RICH
Re: Is this a bug in LazyTurn?
« Reply #18 on: November 04, 2009, 05:32:00 PM »
Dave / Rich,

Wilco. I'll post in "General."

I do have two more identical motors.  I just have to put on my connectors in order to use them.  I don't expect it will make a difference though, because this is a small step motor driving a large leadscrew and the original design didn't require high performance.  If I want performance I'll probably have to spend money.

Dave