I'm seeing a lot of gaps using UltraT on fast speed and 0.19mm layers. They appear on both vertical and horizontal surfaces; if it was horizontal only I'd think maybe it's a feed issue, but the gaps on vertical surfaces appear in roughly the same spot on multiple layers so that explanation is dubious I think. There is no undue friction in the fIlament feed. Not sure if I am seeing the same thing on normal speed... another user has reported a similar problem with UltraT. I'll file a report with support but thought I'd share here as well in case others see the same issue.


Hi Julia,  I have been printing the gears for the clock I just posted on the forum with Ultra-t at 0,19 in both blue and white and have not seen any gaps, but I was printing at normal speed using the Ultra profile.



It more looks as nozzle/temperature problem.

Best Regards

This is a 20 x 18 x 18cm print. The defect is in the same place on each layer - how can it be a nozzle/temp problem if the rest of the layer is ok? Also it seems to be close to a toolpath reversal point in some cases.

@Julia Truchsess

If problem exist only at specific places then extruder cable, please contact with support about this.

Best Regards

Brand new cable just received from Zortrax a few weeks ago and only used for about 20 hrs.

Does it do the same thing when going normal speed Julia?

I'll try normal speed on the next print.


I agree, I am not sure how the extruder cable could cause this. Same with the issue I had of a clog at 98% completed print, it didn't stop turning the stepper, so it doesn't really sound like that is the culprit.


I agree, I am not sure how the extruder cable could cause this. Same with the issue I had of a clog at 98% completed print, it didn't stop turning the stepper, so it doesn't really sound like that is the culprit.

If you had a clog that late in the print it could be caused from a number of variables.

1.Cooling fan temporarily stopped 

2. Connection to thermisistor or heating element loose or disconnected

3. Snag in filament (Had this happen to me on a 50 hour print)

4. Break in wire from ribbon cable that looses contact when cable is stretched 

5. Low fan on nozzle and you get to an area of a print that does not allow proper time for the filament to cool for example if you were printing a cone with the tip at the top more heat would be applied to your layers as you increased z depth.

If Julia is able to print successfully in normal speed with Z ultrat then Zortrax may have to increase the flow rate on the profile for Z ultrat in fast speed by a small margin.

Your issue is different then Julias 

I had exactly the same problem printing with Ultrat at fast speed.

Here's a photo of the entire part, to give better perspective. The vast majority of it printed fine; the gaps appear only in a few places, but they are not entirely random since they occur on multiple layers.

Same issue here. High speed + ultrat + thin walls - > gaps/missing parts of layers, mostly around the z-seam area. It's noticeably better at normal speed, but for a large print (~15hours on 'fast') normal speed takes way too much time. New hotend, no ribbon problems. I'll find & post some pics when I can.

Ah, so it's not just me. Thanks, Catalin! Yeah, my print is 18 hours on fast, gonna be a long one on normal.

Julia, when you say 'at the same place' do you mean at the same location in the model itself or at the same place in the printing task?

If it is the former, what happens when you rotate the model ?

The defects on vertical surfaces are present at roughly the same X-Y coordinates across multiple layers, but not across all layers - see the photos. I've only printed this model once, so have no data for different orientations, settings, etc. You're correct that if the same defect appeared at the same X-Y relative to the printer but with the model rotated, that would point to a mechanical problem with my machine. Since there seems to be a correlation with toolpath reversal (seams) however, I suspect that it's a slicer/Z-code issue - not able to supply enough material flow under certain conditions.



Specs are:


0.09 layers

High speed

Infill Light

0% cooling

Avoid holes

Top surface layers 6

Random seam

Platform cleaned and leveled before printing

UHU glue applied (actually Pritt extra strong)

Case enclosed

Any toughts?

I need to finish this job.  :(

General view (all the area was used, this model is just at the space limit)

Attachment 472 not found.


Attachment 471 not found.

Ugly warping

Attachment 473 not found.

Attachment 474 not found.


venosa, did you hollow the element, or is it solid with just the light infill?

Since the areas with a higher density of material are more prone for shrinking you might consider to hollow out the structure. Depending on the steepness you might even speed up things as long as you don't need support "inside" the hollowed out element...

just an idea...

good luck


Hi Andreas,

Isn't hollow.

I tried the mesh infill (Z-Suite hollow mode) but didn't worked well with this model.

I will try to hollow with Netfabb, but with thicker walls then these calculated by Z-Suite.


In case you do not succeed with netfabb, you can sent me the file if you like and i will try my luck...

In which programm did you create it?