Backlash problems.

Hello,

To resume, I have only backlash on Y axis and not on X axis on a CoreXY system. (two motors need to move when travelling in X or Y axis)

So finally, I don't thing it's a belt or pulley (gt2) problem, as only one axis have backlash. (around 0.1mm)
The structure is in aluminium profile, so I don't think the frame have deformation...

Maybe somebody have experienced that problem, because I look on it since 2months without find a solution...

Please I have lost too much hair with that problem!!

Regards

Is there absolutely no play in any of the guide wheels, and are you sure that all the guide wheels' pins are firmly locked in the alumiminum plate?

Is your belt tight enough?

Can it be that one of the axis' smooth rods is not locked in place?

I have little gap with iglidur bush, but why only y axis and not x. ( fyi: y axis move all gantry, and x axis only nozzle carriage).

I have try different belt tension without any change.

Both axis rod and pulley have been check and are locked.

Thanks for your help ohmarinus but nothing good :-(

how much play is there from tip of nozzle, is there any wiggle when the motors are powered up?

is there any slop in the bushings or bearings, and how far from the bed is the carriage. normally you want it really close to prevent the slightest slop from having an effect on print position.

also do you have a picture of your setup?

. i would assume corexy is the H bot style.


what kind of belts are you using to hold position, are they Kevlar reinforced? how tight are the belts, and do you have the ability to control tension on them?

is your belt drive level throughout the range of motion for the carriage, the belt is level and same height throughout the travel?

again a picture of your machine may help, some one likely more knowledgeable than me will have an answer for you!

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jamesdanielv
how much play is there from tip of nozzle, is there any wiggle when the motors are powered up?

Almost no wiggle (with comparator fixed on the structure, only 0.02mm) , only when I force, I start to bend the 8mm axis.

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is there any slop in the bushings or bearings, and how far from the bed is the carriage. normally you want it really close to prevent the slightest slop from having an effect on print position.

Distance between center of axis rod and nozzle tip = 32mm.

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also do you have a picture of your setup?

So i don't want to make "ad" for my project but there is some photo there:
http://forums.reprap.org/read.php?4,297740

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. i would assume corexy is the H bot style.

Nop it's a real CoreXY (two belts, one crossover), and not a Hbot one(one belt, no crossover)
But definitly it's and Hbelt path

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what kind of belts are you using to hold position, are they Kevlar reinforced? how tight are the belts, and do you have the ability to control tension on them?

GT2 belt (I thing it's polyamide inside and not kevlar). I have two tensionner, one on each belt. (screws + bearing + arm method)

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is your belt drive level throughout the range of motion for the carriage, the belt is level and same height throughout the travel?

All pulley are level, there is a little shift when travelling, but as everytime, why Y axis and not on X axis.... (I can't feal/measure moving part, when I move 0.1 after -0.1mm distance only on Y)

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again a picture of your machine may help, some one likely more knowledgeable than me will have an answer for you!

First post of my thread on reprapper channel.

Edited 1 time(s). Last edit at 06/08/2014 05:21PM by zelogik.

An admin can put SOLVED on the topic

Finally I have found the problem. It's was just stick-slip of Igus iglidur bush, really quiet but need some oil/lubricant for working better.

So now, no more backlash