Wiggle on X-axis. Please help.

[Atlant]

Hello, everyone.
I have a problem with mine 30*40 cm 2500mW laser from Banggood. I assembled it according to instructions - frame is sturdy and square. No problems with software/drivers.
But, when I try to burn something, I cannot get straight lines on X-axis.
Originally I thought that wires were too short and strain from them pulled laser cartridge, causing this "wiggle". So, I extended both wires (motor and laser) by soldering (no connectors were added).
To eliminate any pull-force I installed "wire support" to run wires up from control board and down to cartridge. This did not help.
Then I though that cartridge is unbalanced (I can quite easily wiggle it on rail), so I put some weight on one side thinking that this force will put it to same angle all the time and I will have straight lines. This did not help either..
Lines are wiggle, but parallel to each other, so it's something mechanical. I thought that it could be warped rollers, rotated them separately, but this did not help either.
My last resort will be reassembling laser cartridge and rotating it's rail upside down.
Any other suggestions?

Leo.

[Agastar]

Sounds like the wheels need to be snugged up a bit. There should not be any play when it's tighten up correctly.

[ggallant571]

This is a common problem/complaint. I believe it is partially due to the axles being 0.5mm undersized for the wheel bearings. Try assembling the top such that the wheels hang down before tightening. Then reverse for bottom. Also make sure that the wheel bearings are oiled and turn easily.

[Atlant]

Agastar, thank you for a suggestion - I will tighten them up tonight and post update.
ggallant571 - sorry, but I did not get it. "Try assembling the top such that the wheels hang down before tightening" - do you mean: assemble top 3 wheels first? Then flip over and add 2 bottom wheels? Or something else?
Wheel bearings are new - received unit just 3 weeks ago, and unit is inside of house without any dust.

[Agastar]

By letting the wheels hang down before tightening them up, this will decrease the gap between the wheels and the aluminum extrusion. For the top wheels, you want the bolt to rest at the bottom of the holes in the clear plastic. For the bottom wheels, you want the bolt to be at the top of the holes. So, you let gravity pull the wheels and bolts down and then tighten them up, flip it over and do the same thing.

[beikeland]

The holes on my frame were oval, and shortest in the "Z" direction, making it impossible to get the wheels close enough to the profiles to be snug. Two of my wheels were also wobbling regardless of mounting, waiting for replacements.

I used zip ties to force the wheels as close to each other as possible before tightening screws down and sliding the carriage onto the X axis profile. Made it better, but still need to replace wheels.

[Atlant]

Got it! Thanks! Will try later tonight...

[ggallant571]

I am just starting to get good etches & cuts after 5 months ownership. Dread the need to disassemble the frame to rigidly attach to the safety enclosure. Wonder how we all were duped into purchasing these beasts. Wonder even more why I continue!!! I can't imagine adding belt tensioners and wheel adjusters would add more than $5US to the manufacturing cost.

[Atlant]

Guys, you are the best!
It works beautifully now! Thank you so much!!!!
beikeland - your "life hack" with zip-ties did the trick! Thank you, thank you, thank you!!!!

[mauvan]

same for me tightening helps butr after a while i have same problem again i wonder if it is better to buy bigger wheels ? 1 or 2 mm

[beikeland]

Thinner cable ties so they can remain on? Although mine hasn't come loose, get a socket wrench and tighten them down good? Consider changing to a locknut or apply some thread securing?

Anyway, its not easy to find bigger wheels that still fit; as you would only want them wider. Or you will have to make new parts to install new wheels on. My aim is to do the latter, new wheels, new parts that fit the new wheels, and maybe using a chamfer bit in a router to make a V profile to use with the V profile wheels I've bought. I'll do some tests when stuff arrive from China, could easily be next year due to xmas logistics chaos.

Do post here  if you find wheels that are Ø21.5 and wider than 7mm.

[ggallant571]

I have been looking into getting/making some eccentric bolts to use on the bottom wheels.

[beikeland]

Maker slide use these, but it would require changes to the parts
https://www.inventables.com/technologies/eccentric-spacer

[ggallant571]

I just got an email from openbuilds for a sale on 11/25/2016. They have the eccentic spacers and a variety of wheels.

[beikeland]

I picked up a bunch of 6mm long eccentric spacers off Ali, and matching plain spacers. As I drew up the model of the machine I realize the spacers should be 10mm for the standard wheels. But I'll be using wider wheels to I hope I can get away with it - worst case scenario, I need to mill a pocket for the excess X axis 20x40 profile, which isn't a big deal as I need to make new Y carriage parts for the smaller and wider wheels anyway.