Geeetech prusa i3 axis wobble fix

by shawdreamer Sep 17, 2016
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hi, sorry for such a noob question, i use one of these printed on both side z lead screws? or just 1?

not 100% sure what your asking but If you mean do you have to use both sides then no, the dimensions of these are not altered fundamentally from the originals so as to serve as direct replacements, you can quite happily use only one side if you so choose and leave the other as stock. hope that answers you Q.

sorry ignore the last response I got confused as I was also discussing another of my designs with someone else and got crossed wires there.... yes you need to use the design on both sides for it to be effective, its best to have the whole axis "floating" (eg not physically connected to the z-axis atall) for best results.

I am having some problems. Printed a calibration cube before and after the modification - but the Z wobble seems to be worse
The photo is using the same settings for both two prints - bed is leveled again, and two carriages are on the same height.

The cube with the "1" is the first one printed before the change

Ive only seen that happen once before and that fella had particularly bad bent z-axis lead screws (you could literally see the bend in them just by rotating them slowly in hand), normally Id say the only way to solve the issue was to get new screws and hope their no where near as bent but he tried adding the bearing top mount also and it almost completely removed the wobble lines from his prints. (Id have still said change the lead screws anyway but he seemed happy enough with the result)

tbh though looking at your initial non-fix print it doesnt really look like you need the wobble fix, maybe just the top bearings to alleviate any future stress on the lead screws would be enough.

I bought some trapezoid threaded rods , plum couplers and bearings for the top. But that will be for next year seeing they all come from china.

Meanwhile I keep on experimenting, also tried to add some space between the motor axis and thread for the flex couplers but that made no change.

depending on if the rods/bearings arrive first I will let you know what change helped

Aren't screw too short then? Mine seems to be

are you sure you used the right sized bolts for the parts when you initially put the original together?

If you did then the bolts should be fine.

Should I screw the black metal part with3d printed part and the brass nut or should I screw the 3d printed part with the brass nut directly? And how long screws should be? Sorry for this questions, I',m completeley new to 3d printing and my English isn't best

the brass nut and printed part are bolted together directly, they are then screwed back onto the printers lead screw, the printers metal part then sits ontop of the printed part. the metal printer part is not directly attached to the printed part, it simply sits on it, please see this thingies main picture for a visual representation of the assembly.

Hi and thanks for sharing.
What could be the issue if I screw the printed part also to the metal printer part with a longer screws?


If you do that it renders the whole point of the design meaningless.

the point of separating the lead screw brass nut from the metal carrier is to limit the unwanted horizontal movement caused by the often distorted 8mm linear rods and lead screws the carrier travels up and down on, with the brass nut "floating" (as it does with this design) instead of attached to the carrier any distortion in either the linear rod or the lead screw can only cause very limited effect to a print.

If you screw the printed part to the carrier aswell as the nut then all your doing is adding a very fancy printed washer/spacer and solving nothing of the issue its designed to help fix.

dunno, maybe the print isn't good.Which temperatures have you used?

Thanks ! It works great :)

happy to help and glad to hear its working out for you ;]

bolts go through the part and into the brass nut, the part is entirely seperate from the x-axis ends.

Comments deleted.

Merci pour ce fichier je vais surement améliorer mes impressions

aye I can understand your confusion, generally you'd be right and fundamentally you'd still be right lol, its just Ive reconfigured my Geeetech so the X + Y's are swapped and mirrored so my home position is mechanically at the front of the printer (so the printbed comes forward at the end of a print) and I forgot to take that into account when making the part description, my bad sorry.

Hi Dude :)
Just One question : didn't you make a little confusion between "X" and "Z" axis ??? This part comes bellow the "X" axis support but fixed on the "Z" axis to let the "Z" axis threaded rods move freely without moving the "X" axis support following "X" axis wich make the wobble on the printed parts
On my M201 I noticed that the threaded rods leading the "Z" Axis ( the one for wich you printed this part ) wasn't strictly straight and seem to make wobbles on printed faces parts. I think your build could fix my issue too I will give it a try in the next days ,