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25 Sep 2019 16:19 #146174 by RoberCNC
Replied by RoberCNC on topic moving problem
That I tried with 3A as you told me and the fault still appears. I am reaching a maximum level of despair :pinch:

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25 Sep 2019 16:43 #146175 by tommylight
Replied by tommylight on topic moving problem
OK, that point to physical binding of the mechanical parts.
Can you remove the motor and spin the ball screw by hand, fell if it changes the force needed to turn ?

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25 Sep 2019 17:23 - 25 Sep 2019 17:56 #146176 by RoberCNC
Replied by RoberCNC on topic moving problem
I'm going to do it as soon as I can. You mean you think it points to inaccuracies or construction failures?

I ask because I have also thought about it, even that maybe it would be easier to do something simpler like starting with a fixed gantry machine and a bench with a single ballscrew for each axis.
Last edit: 25 Sep 2019 17:56 by RoberCNC.

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25 Sep 2019 21:29 #146187 by tommylight
Replied by tommylight on topic moving problem

RoberCNC wrote: .........You mean you think it points to inaccuracies or construction failures?

Yes.
If i remember correctly your machine has a single ballscrew under the table for moving Y axis ?
You should definitely check that as they do tend to rack or bend and that causes a lot of friction.

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25 Sep 2019 21:41 #146190 by RoberCNC
Replied by RoberCNC on topic moving problem
no, no, I made it a gantry type which caused me a lot of problems at the beginning and I had to upgrade to the latest version of Linuxcnc and add a double stepper, ballscrew, and limits.

Uff, so surely that's it, which would make me very embarrassed and make me feel really stupid

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25 Sep 2019 21:46 #146192 by tommylight
Replied by tommylight on topic moving problem

RoberCNC wrote: Uff, so surely that's it, which would make me very embarrassed and make me feel really stupid

Not to worry, we have all been there and done that ! :)
Anyway, not such a big deal, stepper motors do not like to spin fast.
The following user(s) said Thank You: RoberCNC

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25 Sep 2019 22:01 #146197 by RoberCNC
Replied by RoberCNC on topic moving problem
I learn that, I have realized that by speed and precision I should have gone to some servos directly, the truth is that the price difference is not so much. As first experience is being very instructive and enriching. I can only be very grateful, really.

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05 Oct 2019 08:49 #147165 by RoberCNC
Replied by RoberCNC on topic moving problem
Hello everyone.
Definitely the two Y ballscrews are very off center. Since the solution involves manufacturing new parts with basic tools and the difficulty that entails, I am considering making the union between motor and ballscrew by means of pulley and belt, even leaving aside the ballscrews at the moment and making the transmission with shapeoko type belt . I found a page in the UK that supplies pulleys and T5 belts, would they be valid for a hundredths precision? What other solutions do you advise me? I am open to all kinds of ideas and information.
Thank you.

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05 Oct 2019 09:16 #147166 by tommylight
Replied by tommylight on topic moving problem
Since you already have them, all other ideas are void and frankly useless.
Make them work, whatever it takes. See if you can find a small shop that can help you with what you need to make it work, or just try it again and again.
If you turn them by hand, you can notice when they are not properly mounted as the ammount of force changes drastically when they are off center.
Anither idea, since it is a small macine, you can mount only one ballscrew under the table and have it moving the gantry. Check the internet, there are plenty of machines that have only one of them under the table.
Using belts on a router is a no no, for way to many reasons.
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05 Oct 2019 09:28 - 05 Oct 2019 09:38 #147170 by RoberCNC
Replied by RoberCNC on topic moving problem
Understood.
Yes, I have seen many machines of the type that you say but I would be doing everything again, so I will have to do and do what I have as you say. Thank you very much for your opinion and help, it is very valuable for me.

I said about joining stepper and ballscrew by pulley and belt because and observed that all the machines at work are built like this and it has always caught my attention and now that I am having all these problems I think I understand why, it offers flexibility since you don't have to perfectly align the stepper and ballscrew centers and I suppose that it has the advantage of offering greater precision of the ballscrew by means of the pulley relation and avoiding microstepping and the loss of Torque that entails it, I don't know if I'm right.
Last edit: 05 Oct 2019 09:38 by RoberCNC.

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