Apparent Step Errors MKII

More
25 May 2021 03:35 #210178 by jnwinkie
Replied by jnwinkie on topic Apparent Step Errors MKII
Thanks all;

Tommy are you saying that either approach should be OK, with regards the reduction belt tensioning? I don't really have the equipment to mill accurate slots for motor movement unless I send it out to be done. Am I working with a failed design? Is there also a chance I have mis-configured the motor setup in LinuxCNC. Boy I am swimming in the deep end of the pool here. Any advice gratefully received

Please Log in or Create an account to join the conversation.

More
25 May 2021 07:31 #210197 by samforsey12345
Have you got a drill and a file? I don't think precision is particularly important, aslong as there is enough movement to get the belt tight and lock the motor solid. The adjustable tensioner would be a nice solution too!

I wouldn't worry about the design, but there is one thing for sure, with loose belts you effectively have a large amount of backlash, so every-time an axis changes direction it will seem like you have lost steps.

To test if your belts are tight enough, you can simply stall the stepper motors and apply force along each axis. It should require significant effort to get the axis to deflect/move.
The following user(s) said Thank You: jnwinkie

Please Log in or Create an account to join the conversation.

More
30 May 2021 04:16 #210655 by jnwinkie
Replied by jnwinkie on topic Apparent Step Errors MKII
Thanks for the feedback.

I have tried to tighten belts and take out backlash, but am still finding issues. I also have a betting bearing setup now for the x drive.

Any other thoughts gratefully appreciated.

John
Attachments:

Please Log in or Create an account to join the conversation.

More
30 May 2021 10:01 #210666 by tommylight
What issues ?

Please Log in or Create an account to join the conversation.

More
30 May 2021 20:32 - 30 May 2021 20:41 #210736 by samforsey12345
Good work on the primary reduction tensioner. Just the ticket.

Can you show some more pictures of the rest of the belts in the system both x and y? From the pics it looks like there is some slop/backlash in the x axis still.

How much pressure do you have to apply by hand to deflect the carriages?
Last edit: 30 May 2021 20:41 by samforsey12345.
The following user(s) said Thank You: jnwinkie

Please Log in or Create an account to join the conversation.

More
30 May 2021 22:53 #210757 by jnwinkie
Replied by jnwinkie on topic Apparent Step Errors MKII
Thanks Sam;

OK will take extra pics and post later today. I appreciate the feedback.

Takes quite a bit of pressure to stall the motors.

Tommy, if you look at the pics it seems either the X or Y is not keeping up and causing an almost straight line in the circle.

I will re-tension everything today but must admit I am stumped as to any other reason why the table behaves the way it does.

Thanks

John

Please Log in or Create an account to join the conversation.

More
30 May 2021 23:40 #210759 by tommylight
A video might help.
The following user(s) said Thank You: jnwinkie

Please Log in or Create an account to join the conversation.

More
31 May 2021 00:23 #210762 by jnwinkie
Replied by jnwinkie on topic Apparent Step Errors MKII
Thanks Tommy;

I will try to shoot some video for you to look at.

Thanks for the help.

John.

Please Log in or Create an account to join the conversation.

More
31 May 2021 04:26 #210770 by jnwinkie
Replied by jnwinkie on topic Apparent Step Errors MKII
Thanks Tommy;

Went to add video and it would not let me.
I tried wrapping it as a .rar file, but it is still too big, even after compression. I really compressed it hard and the sound is bad, so turn down the volume what playing it. If it doesn't help I can send you a larger file directly.
I have tightened all the belts and pulleys and made sure the gantry is square to the table.
I have also added a pic of the vid output and it still shows the distortion of the circle.

I am at a loss as to what else to check out, so any leads gratefully accepted.
Attachments:

Please Log in or Create an account to join the conversation.

More
01 Jun 2021 11:41 - 01 Jun 2021 12:34 #210877 by samforsey12345
Sorry, I don't think I communicated effectively.

With the stepper motors stalled (not moving but engaged), how much force does it require to get your axis to deflect back and forth? and by how much? This may also tell you if a pulley is slipping on a shaft.

I would expect to be able to move it by 1-3mm with significant pressure by hand, but no more than that!

I still don't know what the entirety of your setup looks like - is there another pulley on the side opposite where your stepper motor and reduction is? Does that just free wheel?

Looking at the video, I would recommend keeping the belt parallel at all times. Without knowing exactly how you have it setup it is hard to say whether this would is a problem, but it could be.

Also, can you accurately measure the square you have made in all dimensions - lengths of side and for square. This might help pinpoint any issues
Last edit: 01 Jun 2021 12:34 by samforsey12345.
The following user(s) said Thank You: jnwinkie

Please Log in or Create an account to join the conversation.

Time to create page: 0.128 seconds
Powered by Kunena Forum