Stepper motor - loss of steps

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29 Jun 2019 09:45 #138167 by Jocman

setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0
setp stepgen.0.dirhold 44000
setp stepgen.0.dirsetup 44000

Your DIR setup and hold times of 44000 are probably OK but steplen and stepspace should be set to something like 10000 or even 20000. These numbers are nanoseconds so 10000 would give a value of 10 uSec.


Uhmmmm.....I'm getting a little bit lost
Ok, I understand the change of values for stepspace and steplen (I'll change to 15000, in the middle, according to your suggestion)

5microstepping is also a steplos killer

better to use externel timingbelts for balscrew it is 20/25 teeth so 1,25 gear
that brings in 0,01mm per step at halfstepping
and gets a full speed full torque running mashine

the
color code is most
A+ RED
A- Blue
B+ Green
B- Black

if you change like most Black /green it will likly loos at higher speed at around 100RPM of the stepper


But I'm a little bit confused about this, if you can kindly explain me the thing....

BTW, as suggested by persei8, I'm planning (wife and job allowing - and weather too, my garage is hot like an oven) to overhaul the mechanics and the wiring too, hopefully in the next days

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08 Jul 2019 09:49 #138850 by Jocman
Past week I checked the structure, then this weekend I checked the electronics and stepper.
When disassembled the steppers, I found the X coupler broken.....
Maybe an invisible crack (factory?) wich eventually gave up.
Well, I'll go on with the review of all (mechanics and electronics) and see what will go on.

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08 Jul 2019 11:19 #138854 by persei8
If it's broken then I assume it is the spiral cut type? I've had those break too but now I use the kind with the plastic spider. Just make sure the set screws are good and tight.

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08 Jul 2019 14:56 #138862 by Jocman
yes, the spiral ones.
I was thinking to switch to the ones with the plastic spider too.
I hope to find the type I need.
I got even new steppers (nema 23 again) but with bigger shaft (14 mm)
I should find the right couplers with my screw shafts (6 mm)

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08 Jul 2019 15:00 - 08 Jul 2019 15:08 #138863 by andypugh
A useful search term is "Lovejoy Coupling" though that is a particular trademark for the generic " Jaw Coupling "

Though by the time you have bought all three parts, you can have spent a lot of money. Also, whilst the fact that you buy all the parts seprately means that you can mix shaft sizes, I am not finding it easy to find one that covers 14mm and 6mm in the same coupling size.
uk.rs-online.com/web/p/couplings/7019137/
Last edit: 08 Jul 2019 15:08 by andypugh.

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08 Jul 2019 15:33 #138866 by pl7i92
coupeling shoudt be tight
so best is with a "little flex" TIMING belt
as well you can increase the ACC by 200% as it is more capable of Stepper microstep acceleration at least my expirience
and you can also get a better accuracy performence

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08 Jul 2019 20:50 #138891 by rodw
Replied by rodw on topic Stepper motor - loss of steps
Don't skimp on your coupling. Start by calculating the torque requirements of your motor and then compare that with the backlash free spec for the coupler. Make sure what you buy is capable of handling your torque. I started with a spiral one and ended up buying one from a motion control specialist locally. Its similar to a Lovejoy coupling. It cost me about $70 but at least I knew it was ft for purpose.

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09 Jul 2019 07:29 #138929 by Jocman
I'm finding it's not really easy to get the full coupler (6+spider+14).
One of the lot of reasons I love US, is the fact that you can find almost "everything", even if you're a "lesser being". Here in Italy if you're not a tycoon, it's really hard to find a company (don't dare to think about "shops") which will sell you something; and for sure, absolutely not cheap. And even if you find a "specialized shop" for "lesser beings" , the most of time they ask you "what the hell is that???".... specialized shops.....
Thus, I'll search the best solution I can, even the "chinese allied".
Change my setup from "direct driven" to "belt driven" won't be so easy (at least to me), so I think I'll keep my setup.

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09 Jul 2019 09:42 #138937 by rodw
Replied by rodw on topic Stepper motor - loss of steps

I'm finding it's not really easy to get the full coupler (6+spider+14).
One of the lot of reasons I love US, is the fact that you can find almost "everything", even if you're a "lesser being". Here in Italy if you're not a tycoon, it's really hard to find a company (don't dare to think about "shops") which will sell you something; and for sure, absolutely not cheap. And even if you find a "specialized shop" for "lesser beings" , the most of time they ask you "what the hell is that???".... specialized shops.....
Thus, I'll search the best solution I can, even the "chinese allied".
Change my setup from "direct driven" to "belt driven" won't be so easy (at least to me), so I think I'll keep my setup.


I thought the Oldham or Lovejoy couplings were UK based. On the other side of the world, I ended up with a very overpriced one made in Thailand from my bearing shop.

Also the belt drive is not that hard. The guys here made me change mine from direct drive to belt driven reduction and I made it bolt on where the motor was. See this thread from Page 2. forum.linuxcnc.org/30-cnc-machines/31509...pinion-drive?start=0

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09 Jul 2019 10:32 #138941 by andypugh

I'm finding it's not really easy to get the full coupler (6+spider+14).
One of the lot of reasons I love US, is the fact that you can find almost "everything", even if you're a "lesser being". Here in Italy if you're not a tycoon, it's really hard to find a company


it.rs-online.com/web/p/giunti/8371050/

(pilot bore 6mm, can be bored to a maximum of 14mm)

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