#Troubleshooting height limited defects | zits & inconsistent surface texture

1 messages · Page 1 of 1 (latest)

vernal valve
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Hey all,

TL;DR: Does anyone have a clue, what could cause these defects only within this limited height/area?

  • Snapmaker U1 0.4mm nozzle / Snapmaker Orca
  • 0,2mm layers
  • fully calibrated (all orca calibrations)
  • Max flow rate calibration is immaculate (no such defects appear), filament profile has 25% headroom
  • no other parts (with straight walls) printed in the same area are defective -> no mechanical fault

After printing the Prusa BenchBin, I was trying to figure out why the inside surfaces where not smooth.
(like the outer surface would "press" through: Turns out, gap fill was the cause)

Therefor I focused on the upper section of the BenchBin.
After turning off gap fill (set "filter out tiny gaps": 999999999), I now have the following defects:

  • ONLY within a limited height (approx. 5.6 - 11.6mm z-height):
  • zits shiny / inconsistent surface texture(zits can be mostly scraped off, with a fingernail)
  • The same surface / geometry is immaculate above and below this area.

Speed/flow is consistent over the whole part (see screenshot), changes in geometry (more/fewer corners) also do not coincide with the defective area.

What I've already tried to resolve:

  • The failure mode is the same on the other outside
    • across different colors of filament
    • and different extruders.
  • Increasing temperature by 10°C
  • decreasing Maximum Flow by 10% (-> slower speed)
  • disabling pressure advance
  • decrease flow multiplier by 2.5% (to check for overextrusion)

nothing made a visual difference!

If anyone has a clue, what is going wrong, or how I could diagnose what's wrong: I'd highly appreciate you reaching out!

zits_partial.jpeg troubleshooting-height-limited-defects-zigs-inconsistent-v0-0u9xulmu6wig1.png
obsidian nimbusBOT
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AI Help

It sounds like you have already done a thorough investigation and troubleshooting on your 3D printer. Based on the information provided, the issue appears to be localized within a specific z-height range and not related to speed, temperature, flow rate, or extruder. Since the issue persists across different filaments and extruders, it may be related to the layer height or settings specific to that z-height range.

To further diagnose the issue, you could try the following steps:

  1. Check the gcode file: Review the gcode file for that specific z-height range to see if there are any anomalies or inconsistencies in the commands being sent to the printer.

  2. Slice a test model: Slice a simple test model with similar geometry to the problematic section of the BenchBin and print it at the affected z-height range to see if the issue persists.

  3. Check for physical obstructions: Inspect the printer's nozzle and hotend for any debris or obstructions that may be causing the issue at that s...

WARNING: This response is AI generated and may contain errors.
sinful vessel
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Looks like bubbles during printing. Try drying your filament

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Also if this happens at a specific height range, inspect the Z axis screws or belts, check for wobble

vernal valve
sinful vessel
vernal valve
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If I print more layers below (this is only the top of a larger model) the defect region shifts with that amount.

It looks like it's a combination of my profile/settings with that specific part of geometry - although I can't figure out what it might be

vernal valve
sinful vessel
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Can you split the model in the slicer at that height and see if the inside has malformed geometry?

vernal valve
sinful vessel
vernal valve
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no worries, thanks for taking your time anyway!

Until now, I just inspected preview & gcode (I thought this is what matters, b/c that's going to the printer)
edit: Cutting does not show anything out of the ordinary

obsidian nimbusBOT
#
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vernal valve
#

#reopen

vernal valve
#

#reopen

obsidian nimbusBOT
#
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vernal valve
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#reopen

sinful vessel
vernal valve
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As am I, hence this post.

I've tried to, but at 200mm/s that all happens quite fast - I can't really tell, what is happening

vernal valve
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#reopen

obsidian nimbusBOT
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vernal valve
#

#reopen

timber flame
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Can you post a screen shot of all the slicer views using the right drop down please? (Might say colour or type atm)

vernal valve
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This is at 8.0mm, approx. in the middle of the defective height.

from 0~5.6mm there is no flaws (so you know, what to compare)
(in hindsight the perspective might not be ideal, I hope you can see all you want to see?)

timber flame
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it's interesting the lines on layer time differ in a pattern, does that happen further up the model too?

vernal valve
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defects are approx. between the red lines

image.png
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do you have any idea, what the difference in layer time could cause the defects I get?

(It's late, going to bed. Would be glad, if we could continue tomorrow? Br, & Thanks!)

timber flame
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Possibly fixes:

  • capping speed.
  • upping max layer time.
obsidian nimbusBOT
#
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vernal valve
obsidian nimbusBOT
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vernal valve
# timber flame Put 🔖 on the post. Difference in speed \ temp can lead to uneven size -> sticks...

@timber flame Thanks again for your time, and pointing me in the right direction - although not for the reasons you suggested:

Workarounds that work for me in this case:

  • avoid crossing walls

It seems, that there is still some oozing/(invisible) stringing/whatever, that seems to tear /& deposit material when crossing already printed geometry.
Compare the Travel moves in the slicer pictures and the result after crossing walls to the initial result.

Does anyone have pointers on how to fix or further diagnose what is happening here?
(short of a high speed camera. Best I can do is 60fps with an action cam/phone)

I also notice something related: "pin holes" where travel moves cross the outer layer of a print: see the silk PLA duck image. I hope you can see what I'm trying to show, it's hard to get all of them in focus.

It's definitely NOT:

  • speed (checked 3/4 and half)
  • acceleration (checked half)
  • Y axis related/ tilting of head b/c of inertia (same, when part is rotated 90°)
  • min layer time (could theoretically be layer time difference but I highly doubt it.)
zits_Xwalls.jpeg image.png image.png travel_pinholes.jpeg
timber flame
vernal valve
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Retraction in the supplier's profile (Snapmaker Snapspeed PLA) is recommended at 1.2mm

I've tried with 0.4, 0.6, 1.2, and 3.0mm - none of those settings seem to be discernible regarding these defects

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Wipe settings as per screenshot.
Apart from playing with wipe on loops / before external loops: anything else I'm supposed to try?

RE: speed - Did you mean, decreasing retraction would make the print faster?

image.png
timber flame
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Yeah, sometimes you need to re-test it using orcas inbuilt test.
If not this, it could be:

Those last stringy bits are possibly from last layer not sticking. It can be from being too cold or too fast.