Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Robhi on October 07, 2013, 06:51:58 PM

Title: X axes loosing steps, helps pls
Post by: Robhi on October 07, 2013, 06:51:58 PM

Hello,

I have built a router for wood working, with servo motors, Y and Z axes are ok, but X axis is loosing steps when it accélérâtes a little bit.
I use geckos 320x drives with digital encoders 500 lines. servo motors KL34-180-90 and power supply of 72 volt.

X axes is working with  A axes as slave. pully 2:1 and screw of 10mm pitch.
Y and Z axes 3:1 and rhe screw is also 10 mm pitch.

the prblem is when the machine is cutting it does not loose steps, but when the z axes is up and it moves x axes fast it looses steps and motors bocomes jerking or something like that.

I usually use 500 for the feedrate .

I have attached my xml file, if it will be needed.

hoping to get your help.

thanks a lot
Robhi
 

Title: Re: X axes loosing steps, helps pls
Post by: ger21 on October 07, 2013, 07:05:41 PM

Servos don't lose steps. If it's losing position, it's probably a problem with your encoders.

Title: Re: X axes loosing steps, helps pls
Post by: Robhi on October 07, 2013, 07:44:42 PM

ok, thanks so much.
how could I know that? and what should I do to resolve the prblem?
thanks

Robhi

Title: Re: X axes loosing steps, helps pls
Post by: Hood on October 08, 2013, 03:02:41 AM

Have you tried a wider pulse?
Hood

Title: Re: X axes loosing steps, helps pls
Post by: Robhi on October 08, 2013, 09:29:33 AM

I have just tried it but there is no use. I put from 1 to five , but the problem is still the same.
I would like to to add another thing that may help. I have to power supplies , they are the same. I have wired the x axis to the first power supply, and the A (slave axes) to the other one. do you think the problem comes from ? should I power the 2 axes, X and slave to one power supply?

I have just tried it but there is no use. I put from 1 to five , but the problem is still the same.
I would like to to add another thing that may help. I have to power supplies , they are the same. I have wired the x axis to the first power supply, and the A (slave axes) to the other one. do you think the problem comes from ? should I power the 2 axes, X and slave to one power supply?

Attached some pics.
thanks

Robhi

Title: Re: X axes loosing steps, helps pls
Post by: Hood on October 08, 2013, 09:44:11 AM

You may have to start swapping ot drives and motors to see if the problem follows the swapped hardware.

Hood

Title: Re: X axes loosing steps, helps pls
Post by: Robhi on October 08, 2013, 10:25:22 AM

Ok I will try to do so.

thanks

Robhi

Title: Re: X axes loosing steps, helps pls
Post by: Robhi on October 09, 2013, 08:41:55 AM

I put 3330 in the velocity and 410 in the acceleration. it is ok and every thing is going fine. but it is not fast. I would like to have a little bit more speed. is there some thing to do for having more speed?

Thanks

Robhi

Title: Re: X axes loosing steps, helps pls
Post by: Hood on October 09, 2013, 09:23:54 AM

Just sounds like your motor may be too small for the axis or possibly the axis binding.

Hood

Title: Re: X axes loosing steps, helps pls
Post by: Robhi on October 09, 2013, 02:29:59 PM

Ok ,
Now I use pullies 3:1 and 2:1. My question is if I use pullies 1:1, what do you think, is it possible?
if not what kind of servo motors do advise me to have, which can be driven by gecko 320x?
thanks

Robhi

Title: Re: X axes loosing steps, helps pls
Post by: Hood on October 09, 2013, 04:33:17 PM

If your problem is the motor not being big enough to move the axis then going 1:1 will make it worse as you will be reducing the torque. Afraid I cant really say what you would need as each machine will be different as it depends on weight, friction etc.
 To be sure it is still not a motor or drive or computer issue you should really swap over components one at a time to make sure the problem axis is always the same.
Hood

Title: Re: X axes loosing steps, helps pls
Post by: Robhi on October 09, 2013, 05:01:13 PM

some times I think the problem comes from gecko drives. all gecko drives that I have are set to 11 o'clock. could I set them for more than 11 o'clock to have more current? if yes, do you think it will resolve a little bit the problem?

thanks

Robhi

Title: Re: X axes loosing steps, helps pls
Post by: Hood on October 09, 2013, 05:12:49 PM

Afraid I dont know anything about the Gecko servo drives, I have never used them :(
Hood

Title: Re: X axes loosing steps, helps pls
Post by: Robhi on October 09, 2013, 05:26:13 PM

ok Hood..thanks too much you are so kind..

thanks for all of you too.

Robhi