Why does dragon have a bad case of acne?

I printed this dragon.


0.09 mm layer, ULTRAT, light infill, 0 degree support. (The zcode file is too large to upload here.)

Firmware 1.0.0 and Z-suite 1.3.0

It came out pretty good, except I got a lot of "pimples" on the top sides of the wings and the right side of the body.

The dragon's belly and the underside of the wings came out perfect.

What causes these pimples and how do I prevent them?

You printed this without any support?

Did you use the normal or high setting?

Normal or Random seam?

What fan setting did you use?

Do you have side covers on the Printer?

When was the machine last calibrated?

You printed this without any support?

Yes, it printed without support.  The dragon was designed to print that way.  

There was a slight imperfection around the bellybutton area where things are pretty horizontal, but it's hardly noticeable.  

Did you use the normal or high setting?

> Normal or Random seam?

> What fan setting did you use?

> Do you have side covers on the Printer?

Normal speed setting.  Random seam.  Auto fan.  Yes, with side covers. 

When was the machine last calibrated?  

You mean level the platform?  About two days ago.  

I would suggest trying again with normal seem and seeing what happens; random has a history of giving people issues. 

I printed this dragon a long time ago with random seams - she ended up with "zippers" at random places, but no pimples. That was many slicer versions ago, though:


I've been getting these blobs a lot lately too, and I'm using normal seams almost exclusively.

I once had the same problem when printing several pieces of the same object, distributed over the building plattform. The "pimples" were concentrated in a certain area. Since the very same object was printed flawlessly in all other areas of the building plattform I considered it very unlikely that the reason was material, the object itself, or an extruder issue.

When moving the extruder by hand I found out there was a slight stutter or higher resistance in the X-Y area where the problem occurred. Removed the old grease and applied new, problem was gone.

Now I remove the grease with cleaner solvent every 5 printing hours and renew it. Takes just 2 minutes.

When moving around the extruder by hand grasp it very low, at the height where the rods are. So you can feel the needed force pretty good.

May the force be with you ;)



Thanks, Andi. What solvent do you use?

I use this one: https://profiteile.de/liqui-moly-schnell-reiniger-kaltreiniger-500-ml

cause I had it at hand. However I guess its not necessary since the degree of pollution in the printer will never be as high as it is in a mill. So a tissue with Aceton, which is a very good dissolver, will be sufficient. Take care not to touch the belts or any other plastic parts, just wipe off the old grease - which will be dark grey or black - and bring on some new one.



Do you grease the outer rods as well as the 4 inner ones? I've read that bronze bushings should not be greased.

Well yes, I do, but not as often as the outer ones.  Reason is, the outer rods collect much more dirt than the inner ones, I believe cause of a kind of chimney effect the leads the warm air from the plattform around the outer rods.

I know that bronze bushings need not to be greased, however, if you ask 5 experts you get 6 opinions :)

According to my experience it is a good idea to keep the rods clean, and that can be done by removing the old grease and apply new. Just a bit. Dont choke the rod.

Certanly bronze bushings need not to be greased when they are enclosed or operate in an environment where dust an dirt is no factor.

But even if I do reduce the lifespan of the bushings by a few percent, I guess I have to live with that, cause it makes no sense to me to trade lifespan with sloppy prints.



Thanks Andi, appreciate your insights :)

I also have to grease the rods.

What kind of grease should I use?

The small tube Zortrax is empty!


Can you use lubricants Teflon spray?

Super Lube


Thanks Julia, you are very welcome :)

Lets hope that the dragon will be cured from its acne :D



thanks for de reply :)

The blobbing is due to oozing when the extruder is jumping from one area of the build to another, during the transit a small amount of plastic oozes out and is wiped off on the outside surface as the nozzle moves over the wall.

The reason this crops up from time to time is common with the upgrade to the software, “speeds, feeds and retracts” are tweeked by zortrax and it comes and goes, also as we all know “Not ALL ABS is the same”, so some materials/colors will ooze more than others.

Usually these are easy to clean off.

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Thanks for the explanation, Drew.  That makes sense.  

"Not ALL ABS is the same"

Okay, but this was ULTRAT. Does that saying apply to ULTRAT too?

“Okay, but this was ULTRAT. Does that saying apply to ULTRAT too?”

It applies to all materials, you will find that there are a multitude of factors that will influence printing, keep in mind that no 3D printer on the market, no matter how big or expensive is “Fully Consumer Ready”, there will always be issues as it is still an evolving industry, it may someday work as well as your average paper printer but that is not the conditions now.

While Zortrax tries to adjust their algorithms for speeds and feeds and temps, the mechanical conditions of and surrounding the printer change as often as the material properties, so what Zortrax programs to is not exactly what you will see.

“Your results may vary” remember that statement from everything, everywhere.

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Hi guys,

Apologies to butt in but is this problem not the same as my problem, and also relating to this problem, and this problem.

Possible explanation is the distance travelled between islands causes a bead of filament to cool which then catches on the next island.

A solution would be better retraction, although I'm not sure how effective retraction is on the M200 with the cog so far from the nozzle. Failing that, dropping the build plate as it passed the perimeter wall so the bead didn't catch. None of which can be done by the user in Z-suite.

Has anyone with older printers or FW/Z-suite combos tried any of these models to see if they have similar problems?


I'm fairly much convinced they got something wrong with the last upgrade to the software.

I'm seeing more blobbing and stringing than ever before on both machines, and it's not due to maintenance or filament.

Communication (or even personality) is not "Z's" strongest suit, but they are serious about their software and print quality.

My guess is they'll say nothing, and it'll get better with future upgrades.