UMO+ Z-axis linear bearing problem ( "clicks" and "crackle")?

[Gnevko 5]

Hi, people!

I have UMO+ (about one month) and if I move my print bed down (just by hand) I hear some strange sound from the linear bearings ... It sounds like "clicks" and "crackle". Is it normal or linear bearing are damaged?

The second question is also about linear bearings but for the XY head moving (in printer head). It seems they have some small play if I try a little bit to sway the nozzle. Is it ok or maybe I need to buy more quality linear bearings?

Thank you in andvance!

Regards,

Alex

[neotko 1,417]

All my umo+ always had really good x/y hotend linear bearings. I would ask the reseller (make a video of the noise you get from the play it has) to see if it's the assembly or the bearing.

The z sandy noise comes from the square flanged bearings on the 12mm dia shafts that hold the bed. That's normal, to check if the Z it's working as it should print a few tall towers and post an image to debug, it should look without marks along z.

Also remember that:

- Sewing oil only goes on the 4 shafts that hold the slide blocks (not x/y thin shafts, also not on the 12mm Z left/right smooth shafts)

- Green lube only on the Z long screw (middle) and not anywhere else.

[Gnevko 5]

Thank you for the quick reply!

0.2 mm layer high is each for the tall towers? or better to use 0.1 mm?

It means that linear bearings shouldn't be oiling at all?

Edited September 21, 2016 by Guest

[neotko 1,417]

That's what I know yea. Ofc cleaning the shafts (thin x/y) with a fiberless cloth doesn't hurt.

0.1 would be better but if there's any real problem it will show on 0.2 too.

Edited September 21, 2016 by Guest

[Gnevko 5]

Ok, now foto

Details:

Size - 10x10x100mm, Layer hight - 0.1 mm, one perimeter, nozzle diameter - 0.4mm.

Right tower: temperature 210C, flow - 100%

Left tower: temperature 216C, flow 110%.

It seams that right tower has a little bit under-extruded layers.

[neotko 1,417]

Thanks for the test,I think your z looks perfect. It might need some lube or cleaning but otherwise all good!

With a print like that I think you don't need to worry about your z bearings at all.

[Gnevko 5]

Thank you for you help and attention!

hm ... but ... my two tower are not really perfect. The left one is a bit better then right but ... is it filament quality problem or maybe mxl belts? Wrong print temperature or extrusion? Vibrations? Maybe software (I use S3D) ? Or is it the best quality what I can have with UMO+ and 0,1mm layer?

Edited September 21, 2016 by Guest

[neotko 1,417]

I think the tower difference could be just filament not being perfect 2.85 (check with a caliper).

Bed vibrations do exist make a small tower in the front and other on the back, you will notice that on the back is more firm.

To reduce some vibrations if you calibrate the bed with the springs tighter it use to help a bit, but most of the vibrations will exist (wood frame vibrations).

On s3d the default Z speed use to be 18ish mm/s I get really good z with 25mm/s

Other main issue, and due EU regulations Ultimaker has their hands tied to change it, is that the bed heats on a bang-bang mode. PID is more precise and helps to keep the bed always at the same temperature (on a .1 range).

If you want to use PID for the bed you might enter the 'mod' area, and while is mostly safe isn't free of risks specially since isn't a official firmware.

https://ultimaker.com/en/resources/20983-ultimaker-original-custom-firmware-builder

With this firmware builder you can make a custom firmware with 'hack' settings. Isn't for the newbies but is really nice.

I use the @amedee 'experimental' version that allows to use PID for the bed.

https://bultimaker.bulles.eu/experimental/

Remember, don't adjust anything that you don't know what is. If you choose this path... well is your choice

Just read the manual before going in. And remember this isn't official, but IMO is the best firmware for umo+

Edited September 22, 2016 by Guest

[Gnevko 5]

Thank you agan

What is your expiriens with GT2 belts? I readed in this forum, that the change from mxl to gt2 - it should be the first step if you want to modify your printer ... but what really stange is if I search for GT2 belts on AliExpress (for example), I see only sets for Ultimaker 2 ... and nothing for Ultimaker Original ...

[neotko 1,417]

Most of the user got them from china robotsomething web I got them on aliexpresss at a seller named ninmgo? Something like that. I think I put the name on https://ultimaker.com/en/community/17068-making-your-own-ultimaker-what-not-to-buy-on-china-stores-personal-experience

The ones of um2 are 4mm wide I think?? Too much info I can't remember all. I think they are a bit longer since they are design to use a spring on their slideblocks, and the um2 slideblocks won't work on umo+.

So about the gt2, read this:

https://ultimaker.com/en/community/15874-mxl-vs-gt2-print-results

Ofc if you wanna go bananas modding you could use um2 slideblocks and gt2, but that would need um2 longer thin shafts, move the endstops, rotate the central bearings of the umo hotend, a lot of changes that ain't for a new user.

Are the gt2 better than mxl? Yes, they are better, have less backlash and if you read ALL the post about mxl gt2 you can do it too. But you will need to be patient, google a lot and use modded firmware (or change x/y esteps). Again, modding is a process that can't be rushed. I remember a user than started to send me msg about changing all parts to misumi, linear bearings all and more and in the end he was so frustrated that I think he went bananas... So don't go this route unless you are really patient and you read everything you can find.

[Gnevko 5]

Also one very interesting photo (from my point of view of course)

As you can see - legs are not really gut .... actually they are terrible (holes, gaps and so on), but "body" itself - has very nice quality. The difference is - "body" has one very long perimeter, legs - short perimeters with a lot of retraction. I think that the  S3D configuration for my UMO+ is a bit wrong

otherwise my towers was printed without retraction but they have also small perimeters (compare to the "body" part on the last photo) ... hm.

Edited September 22, 2016 by Guest

[neotko 1,417]

You might want to raise travel speed to at least 150mm/s, that will help with the driping between moves. Also there's a point where you might need to print cooler/slower to control the dripping.

[Gnevko 5]

I have travel speed - 200 mm/s ... if I try to print cooler then 200C (and of course slower) I have more terrible results ... maybe PLA quality is really the reason. It's Verbatim White PLA.

[Gnevko 5]

Today I made a service for my UMO+ and ...

 

Should it be so?

Edited September 24, 2016 by Guest

[neotko 1,417]

The problem with 'by hand' is that since is linar, if it rotates it can also 'clamp' to the shaft. So Is better to test them with the plate so they move linearly. The weight of the bed can overcome that small momentum that's stuck. But if that's tooo much it can be a problem.

So is can be so, it could be better with topnotch misumi bearings, but also it doesn't seems to be out of the ordinary. I would worry if by moving the Z (Prepare/Move Axis/0.1/Z) and you home, then you use that control to move it step by step down, if while doing so you see that the bed does a small fall, or sudden, then I would worry, otherwise is fine.