[kaetamer]

Was checking calibration of axes using the Motor Tuning and Setup tab of Mach3. X,Y, and A axes all measure exactly correct distance traveled at 1735 steps per. Checking the Z axis, when requesting a move of 5 inches the Z travels 1.9375 in (1 15/16). Mach3 suggests step per at 10322.5 instead of the default 4000. Am I missing something? Is Z axis movement different? I tried the suggested value ONCE and got very little movement of the Z and a lot of high pitched whining. I changed it back and confirmed no damage done. Thanks for for help. Scott

[Mzones]

OK, lets take a take at this. You have your steps set (4,000)
You run a (5.000") move. It only moves (1.9375")
Mach tells you to use (10322.5)


5.000 / 1.9375 =2.5806
10322.5 / 4,000 = 2.5806
5 CM = 1,9685"

Assuming your measurements are a little inaccurate.
This tells me that you calculated steps per cm instead if inches.
that (10322.5) number tells me that you need to check the micro step
settings on the driver board.

As far as the whining of the motor , that won't hurt it. What happened there
is with that (10322.5) steps per inch the motor couldn't handle the acceleration.

It's kind of like pulling the tablecloth out from under the dishes on the dining room table.

Hope this helps you.

Mike

[kaetamer]

Makes sense. Since the other two axes act as if they are in inches not sure what to check for "the micro step
settings on the driver board." It's a 5042 driver board with dip switches for steps/revolution. Maybe I'd better head over to CNCRP for clarification.

[ahren]

Hi All,

The settings in the XML files for our electronics are currently defaulted to our standard mechanical kits, which have an ACME screw drive (4000 steps per inch). The ballscrew axis has a finer pitch, and should be set to 10160 steps/inch. We'll be updating our XML files soon to reflect the matrix of different options on our kits.

Best regards,

Ahren
CNCRouterParts

[kaetamer]

Thanks Ahren for that clarification. Certain jives with what Mach3 was telling me. At the risk of becoming a real pain in the a$$, may I ask a related question now that I changed the steps per to 10160? After doing so, jogging much above 50% jog rate causes a screeching in the motor and a stall. Doesn't seem to matter whether it's Z+ or Z-. After releasing the Z+ or Z- and repressing it the Z moves again only to screech and stall again. Is there some other parameter that needs to be updated or is the motor the problem or ????.

I hope I'm not "wearing out my welcome." Scott

[ahren]

Scott,

Not a problem -- it's probably just an acceleration or velocity setting that is too high, but there could potentially be a mechanical issue. Feel free to contact us through our website or email and we can get someone to help you troubleshoot.

Best regards,

Ahren
CNCRouterParts

[Mzones]

it's probably just an acceleration or velocity setting that is too high, but there could potentially be a mechanical issue.

In Motor tuning check the settings. the setting for motor speed is probably
set way higher than the machines capabilities. also set the acceleration down low,
Check for binding on the ball screw.

Checking the Z axis, when requesting a move of 5 inches the Z travels 1.9375 in (1 15/16). Mach3 suggests step per at 10322.5 instead of the default 4000.

Mach3 suggestion is right, this matches the screw you have.

The ballscrew axis has a finer pitch, and should be set to 10160 steps/inch.
We'll be updating our XML files soon to reflect the matrix of different options on our kits.

Setting steps per at 10160 steps using a 5" move will give you a move of 4.9312"

Evidently the ball screw that you have is not the same as ahren is referring to.


Hope that you making some progress


Mike

[ahren]

The ball screw Scott has is from us, and is a 5mm pitch screw. Our electronics are configured to 2000 microsteps / revolution. Thus, it takes 2000 * 25.4 /5 = 10160 steps to move one inch. Previous discrepancies from this are likely just measurement error.

Best regards,

Ahren
CNCRouterParts

[kaetamer]

Thanks Mike for all your help and thanks to Cory and Ahren at CNCRP for getting a solution to the problem and for the detailed explanation of what was needed. Everyone has been very helpful and since I'm a noobie they will likely get the chance to be helpful again. Scott

[Mzones]

So is everything is working fine now?

What were the problems that you found?

[kjk2002]

I had the same screeching problem going to +Z. I fixed mine by reducing the Z velocity from the configured value of 206.7 to 100. I didn't experiment to see how much faster I could go.

[kjk2002]

Re the previous post - I spoke too soon. When I actually tried cutting something I found I was losing steps going +Z. Consulting with Ahren led me to remove the dust cover from the back of the Z axis which comes pre-assembled from CNCRouterparts. It was the cover which was binding and causing so much friction that almost any additional load caused the stepper to stop. A permanent solution is still needed.

[Gilrock]

I ran into this also. I've been tearing my hair out for days trying to figure out what was going wrong on my Z axis and was emailing Ahren 2 to 3 times a day. I had great repeatability in the Z axis so it didn't look like I was losing steps. But after using a dial gauge to check it out I figured out that it was not able to do small upward moves. Any commands that pulled the router upwards would take 0.020" to even budge it and would land 0.010" short. Ahren had me remove the dust cover yesterday and all my Z axis problems went away.

This thread has all the details of me fighting this issue. It started in that forum section because initially I thought I had a toolpath problem. I didn't realize it was mechanical.
http://www.cnczone.com/forums/aspire...st1430666.html

Checkout the before and after removing the dust cover. Take note of the areas near the curls down the sides and the window panes in the middle. It's not easy to tell from the photos but the features are almost a millimeter taller now.
Attachment 222514Attachment 222516

Thanks,
Gil