Bad Layers inbetween, in every part - why??

[the_mechanical 0]

Hi

I'm using an UMO+ since a week - so there is not much experience ;-)

I don't know why, but in every part there are some bad layers - see pictures.

In the beginning all is ok, the results are good, but after a while there is one (or more) bad layer(s). The z-height where the bad layers are occuring differs only a little - mostly between 10 and 11mm.

Have anyone an idea where the problem is?

After problems with the feeder (Screws get losse, so feeder stopped working - solved) it should be no feeding problem.

Used Cura 2.1.3 for all parts (2.3 beta is not working - no slicing, so not possible to save the g-code file).

Material the Ultimaker PLA provided with the UMO+

Hardware / Software Problem? PT100 failing for a while?

Someone with similar problems?

Thanks for your help.

Edited September 22, 2016 by Guest

[Gnevko 5]

looks like this one http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#z-drop

Edited September 22, 2016 by Guest

[rowiac 48]

I've had my UMO+ for a little over a month, and it had that problem from day one. I tried all the recommended fixes, but I ended up having to replace the Z linear bearings with good quality Misumi ones to completely solve it.

It seems like this problem is very common and may be getting more so. For me the 40USD cost to replace the bearings was well worth it.

See my post here: Z layer error / skipping layers

Try all the fixes on the 3Dverkstan site, and if all else fails, go with the Misumi bearings.

[the_mechanical 0]

Thanks for your replies.

The 3Dverkstan site is very good. I had a look on the z-axis, tried lubrication and adjusting. There is really a part where the axis is sliding heavy. And it's indeed about 10-15mm from the z-End. What's really strange for me is that also this 10-15mm is very common. And looks like the problem is existing since at least two years - and no one is fixing it!!!

Seems like i have to change the z-axis too.

Have the UMO+ since a week, already ordered a GT2 belt and pulleys due to roundness problems, now the z-axis problems, at the moment i'm also having a look on faulty dimensions. So i can't recommend a UMO+ anymore (of course i don't know other products).

[neotko 1,362]

For one of my umo+ kits that didnhave that problem I had some part replaced by the reseller. If is brand new I would contact them, also it would be nice if you can print tall towers, like 3 at the same time of 1cm and 5-10-15cm tall to show the error so they can assist you.

[rowiac 48]

Others have mentioned that the bearings start to jam up shortly after they reverse direction.  Since the platform moves to the top just before a print is started, and it reverses direction to move down as the print progresses, the jam-up occurs in a fairly repeatable location.  The distance to jam-up after direction reversal seems to be the ~12mm you mentioned.

My guess is that the issue has something to do with the ball bearing cage that allows the balls to shift in some undesirable way that causes them to skid against the shaft and each other rather than rolling when the direction reversal occurs.

Edited October 18, 2016 by Guest

[the_mechanical 0]

Thanks for your replies. I'll examine this problem later, at the moment i put some extra weight on the bed - it's ok for the moment, but takes building area.

As i read other posts it looks really like a problem with the bearings, rowiac's explanation seems quite plausible.