anti-backlash nut alternative

[absolutepoker01]

Hi, im building my JGRO, maybe ill post some pics later, but the problem right now is that i couldnt find Delrin or HDPE here on my country for the AB nuts, so i grab a piece of MDF and drill a hole a tad smaller than the outside of a 1/4" nut, then on one side of the hole i put a bolt with a flat washer, and on the other side the nut, so i started to fasten the bolt in order to let the nut insert into the mdf, i also put some white glue to help. The nut seems to be pretty tight. Have any one of you tried this? Could this work? or is there any other solution for my problem?

In the pic the nut is already inside the mdf.
Thanks you all.

[Jason Marsha]

It could work but there would be accelerated wear due to metal to metal contact. Although you might not find Delrin or HDPE lots of people use 1/2" plastic cutting boards, normally available in the housewares section of a home center store.

Jason

[absolutepoker01]

Hi Jason, thanks for the reply, yes i think i can find those cutting boards you mentioned, if it doesnt work i think this would be the way, when you say accelerated wear you mean that the threaded rod will be damaged?

[voltsandbolts]

Originally Posted by absolutepoker01 Hi Jason, thanks for the reply, yes i think i can find those cutting boards you mentioned, if it doesnt work i think this would be the way, when you say accelerated wear you mean that the threaded rod will be damaged?

Yes I think that is what he is saying.

[absolutepoker01]

Hi, so im going to try this AB nuts to see what happens, the pictures show them dry a ready to go, ill coment later it the rod gets hot or something like that because of the friction, like jason said.

[absolutepoker01]

Hello, sorry for the darkness on the video, ill record another one in the day, but you can hear the motor, i dont know if that is stalling, or its beacuse of the AB nuts, any help and comments would be really helpful.

Thanks.

YouTube- Stepper

YouTube- Stepper

[absolutepoker01]

Ok here are some videos that you can actually see something, in the first one the stepper speed is slow, no problem at all, only that it moves really slow, on the second i raised the speed like 3 times, and there is the problem, whats the reason of that?

Thanks, AP.

YouTube- Stepper slow

YouTube- Stepper slow

YouTube- Stepper, faster, stall

YouTube- Stepper, faster, stall

[CarveOne]

That looks and sounds like stalling due to binding somewhere in the mechanics. It could also be caused by resonance of the motor.

CarveOne

[valmet58]

which program do you use to drive your motor?
I had a similar problem using turbocnc and it was due to my setting
start speed which was too high..if you have an acceleration parameter try lowering it.

[absolutepoker01]

Carve,
yes it could be the mechanics, im using a metal nut driven into the MDF, as the pictures in the first post, how can i solve the resonace?
Valmet,
im using mach 3, i have lower the acceleration and may help a little, but still happens sometimes.

[absolutepoker01]

Hi, i changed the parameter of step and direction time on the config of mach3, i set it to 5 us, and result is in the video, this is with the same spped as the last video, where the motor was stalling, but now thers no stall.

YouTube- Stepper, same speed when stalling but no stall

YouTube- Stepper, same speed when stalling but no stall

i thought ive solved the problem, but when i put all the axes together sometimes the motor stalls, but not as much as before.

That parameter of step and directon time is how much the square wave is high right?, what value do you recomend? The gecko max step pulse frec. is 300 Khz, so the the minimum time would be 3.3 us right?

im using gecko 540, 48 V 7 A PSU, 185 oz-in steppers

[voltsandbolts]

Originally Posted by valmet58 which program do you use to drive your motor? I had a similar problem using turbocnc and it was due to my setting start speed which was too high..if you have an acceleration parameter try lowering it.

I have to agree with Valme58, sounds like settings, too quick of a direction change. But it looks like you have started tuning your settings. What voltage are you running your steppers at?