Started to get some random, yet extreme, Z artifacts on one of my UM2's

[joseph-kim 0]

@gr5

@cloakfiend

I made a 3D model for the test. It's 10 x 10 x 10 mm box with 5mm tall extruded curve sitting gently on top.

* My nozzle is thoroughly cleaned out, and can achieve 10 mm^3/s

* All filaments I own gives same result.

Here are the parameters:

 

Material: Colorfabb PLA/PHA Gray

Shell: 0.8 mm

Bottom/Top: 0.8 mm

Fill: 30%

Speed: 50 mm/s

Infill speed: 80 mm/s

Top/bottom speed: 15 mm/s

Outer shell speed: 30 mm/s

Inner shell speed: 60 mm/s

 

 

Here are the results

 

 

Larger layer height seems to make problem worse:

Z current doesn't seem to have any effect: (It sounds a little quieter. I like that.)

Lowering temp down to 205 did not change anything:

Edited October 6, 2015 by Guest

[cloakfiend 995]

They look extremely melted, suggesting it may actually be printing far hotter that it is telling you, as you cant even see the layer lines. i have never seen such melty print my self, and with colorfabb always can print at 205-209c with near perfect results.

Try setting the printer to print at 170 as a test. or just manually dial the temp to 90 and pretend you are doing an atomic pull, and see when the filament start to melt. Mine starts to melt at 130c.  but can only push it through quicker at around 190 upwards. if yours starts meltig earlier then its your heating sensor or heater.

Also if you could post some ultra close up pics of your atomic pulls, to make sure they are ultra perfect. It might help. I get plenty of material flow, even with a blocked nozzle. I did a print yesterday with a blocked nozzle, it came out perfect, only the first layer or two did i hear the clicking and saw it skipping a few lines as it tried to layer them down.

Also try printing without the olsson block installed.....Basically try everything.

Ever since i installed my new PFTE my printer started to act differently after a while. No idea why but thats life. I had to change the way i worked. Maybe the olsson block is giving you issues the way its installed or something? Again i'm just guessing. I was going to get the olsson block myself, but as im in the middle of a crazy job, i just cant risk taking anything apart as if i cant put it back together properly or install something right then i simply wouldn't have the time to fix it.

Edited October 6, 2015 by Guest

[gr5 2,170]

Marlin won't let you print at 170C. If temp dips to 169C then the extruder will stop. So 180C is the lowest you can safely go. Or maybe 175C.

Okay - you convinced me it's a Z problem. I know it looks "melty" but I think that's just a very glossy look. Or maybe it's just a glossy kind of filament.

Those regular lines are too regular to be anything else. What happens is the Z axis isn't moving the entire .1mm or .2mm so you get over extrusion for a layer and it sticks out.

I would contact support.ultimaker.com - your ticket will automatically go to fbrc8.com in memphis. Send them a link to this topic so they can see all the things you tried. Tell them gr5 says you need a complete new Z kit - vertical rods, vertical screw, z motor, z bearings and Z nut.

It's a lot of parts but when you get this problem it could be any one of those. Actually because the problem is so regular I would just get a new Z nut and maybe a Z screw. The distance between those "bad layers" appears to be very consistent - possibly every 3mm (the screw I believe moves up 3mm for each rotation? Maybe? I forget - that was the UMO I think - the UM2 moves farther maybe? Anyway I think support.ultimaker.com is going to help you much faster than any other method at this point because you need to start swapping out Z parts. It's much easier to do than you might think.

[gr5 2,170]

Just for fun - with power off - try moving the bed up and down by hand.  To move it down is easy.  To move it up grab on left and right side near the back of the bed and pull up firmly (the printer may lift off the table for a moment).

Repeat this several times and try to feel for a regular resistance on each rotation or a noise that repeats once per rotation.

Did your printer come with a tiny squeeze tube of green grease?  If so consider cleaning the screw completely with wd40 - especially near the top - then grease it with about one or two  pea-sized drops of grease.

Edited October 6, 2015 by Guest

[cloakfiend 995]

True, even I cant deny those lines look fairly evenly spaced apart. I hope this never happens to me. Looks like a nightmare. I get mad enough just hearing clicks from the feeder, lol.

[joseph-kim 0]

@cloakfiend

The extreme lighting and the glossy nature of that PLA is making it look melty. It's not melty at all actually. In fact, the strata is quite sharp. I am sure the temperature is not an issue. I am very familiar with the consistency vs temperature since I've been printing daily for about a year. The temps are correct for sure.

I do like your idea of swapping out PTFE and the Olsson block. I will give that a shot some time.

@gr5

I've been contacting the US support, but it has not been terribly productive so far. I have even taken the entire Z assembly (brass nut, screw and motor) out and meticulously cleaned it and regreased it with Magnalube. Nothing changes!

[joseph-kim 0]

@gr5

Just got an email from US Support-

They are sending me a new Z-motor and trap nut!

I will let you know how it goes

[gr5 2,170]

Was that after you sent them a link to this topic? ha ha. 2 of the key support people are going on a short vacation so you are lucky! (they still have at least 1 excellent support person behind plus the support people on vacation are bound to work on tickets during their vacation - sigh.).

[joseph-kim 0]

@gr5

You were right on - everything is in perfect working order!

Thank you always gr5 for your quick responses.

[axislab 8]

So if I understand this, you swapped the z motor and nut and all is well now?

I am still having the issue on mine, sadly the machine just sits these past months, printing only flat items, like tokens for makerfaire and such.

[joseph-kim 0]

So if I understand this, you swapped the z motor and nut and all is well now?

I am still having the issue on mine, sadly the machine just sits these past months, printing only flat items, like tokens for makerfaire and such.

I'd try replacing bowden tube. I can now print at 15mm^3/s with this.

[axislab 8]

I started this thread 9 months ago lol.

I think this machine is just done. I am trully, trully at a loss of ideas, or hope for that matter haha.

[gr5 2,170]

A lot of people had this issue recently. They had to clean and sometimes take apart, clean and reassemble their Z stages. For almost everyone it was not so much the Z screw but the two Z shafts and bearings. All those little ball bearings get all jammed up. It turns out there should be no oil used - so take out the 2 vertical shafts (easily done from below) and remove the 2 bearings and clean everything and put it back together. Some people just put a 1kg weight on their bed and that was enough. WD40 is great at cleaning ball bearings. No oil should be needed with ball bearings as they don't slip - they roll.

[axislab 8]

Headtodesk lol.

Firmware update....

9 months of tearing this machine apart, and it's fixed by a firmware update haha.

If this thread isn't the true definition of 3D printing troubleshooting, I don't know what is lol.