Failed Print......

Just for fun

Tim Young
H-M Lifetime Diamond Member
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Oct 7, 2020
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So, I had a hard time getting this to work after maybe the fourth failed start, I used the glue stick and it worked. I could not get the Aquanette that has been recommended, I tried another brand it didn't work.

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The little welding cart for my MIG welder has the handle at 24" high, a little too low for me. I had this old Weed eater handle just laying around. I think it is going to work just fine.

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How did you clean/prep the steel sheet? When I started working with PETG on my MK3s I initially had issues w/ 1st layer adhesion. To fix:
  • I washed the sheet with dish soap and warm water (i've only re-washed once or twice in the past year)
  • In-between prints I'll clean with 99.9% isopropyl (if at all / as needed)
  • Bumped the First Layer Bed Temp to 90*C (default is 85*).
  • Neurotic calibration of the Z-height
With these few things: zero problem w/ adhesion; I do not use any glues. I'm using Prusament's filament by-the-way.

Where is your printer? If in an unheated space: an enclosure would help.
 
Interesting that PETG is giving you adhesion problems. I usually have trouble getting it OFF the bed after the print. I've used glue stick to help as a release agent before, it does work well for me that way. My bed is PEI sheet. I have better luck with the smooth sheets than the textured type. Some of them have a smooth side, give that a go if you have one. If not, sheets with adhesive are reasonably priced online and you can apply it to the back side of a steel sheet for those times you want to use it. If you do, remember you need to re-calibrate the Z-offset.

Looking at the prints, the first layer looks a bit high. And perhaps the bed level is off a bit. Does your printer have a bed probe? A good bed mesh autolevel can help a ton. One of mine is warped and works fine with the mesh leveling enabled.

One trick I've used a few times to help set z-offset.. Print a skirt with a test print, cancel after the skirt is printed in a single layer. Pull it off carefully and measure the thickness with calipers or a mic if you want to get crazy, use that and the first layer height in the slicer to adjust z-offset to dial it in. Once it measures what the slicer says, your offset is "right". You might want to move at most 0.1mm up/down based on the filament type, it helps sometimes.
 
Here is the deal that I thought odd. I have printed several things with PETG, mostly other colors but a few with the black. The black seems to have a different texture, kind of soft feeling, it is Sun-e brand. This time it wouldn't stick. Before I got it working, I managed to plug the nozzle and had to install a new one.

  • I've never washed the build plate.
  • I have whipped it down with 90% isopropyl several times.
  • I did bump the first layer bed temp to 90°C
  • My printer is in the shop and in an enclosure.
  • After the first failed print, I readjusted the Z calibration, it didn't help. I actually adjusted it a few times.
@ttabbal I may have the Z calibration set better now since the photo, but I will recheck it before I print again. I like your idea of measuring the skirt. I'll try that.
 
@ttabbal - PETG will stick TOO well to smooth sheets which is why they make the textured sheet. The textured sheet just requires some tuning for ideal adhesion. I found Bed Temp and Z to be the biggest factors.

@Just for fun - When I wash the sheet: I don't use anything other than my hands (no sponge or scrubber) and I let it air dry. This certainly helped when I first got my textured sheet; don't have to wash it often since.
 
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That explains why my results were different. :)

I have a textured plate for one of the printers. I haven't liked it much. I like the look of the finished print, but PLA doesn't stick well enough to it. I get corner warping even when I lower Z more than I'm comfortable with. Smooth PEI holds it great. I've tried temps and such, but part of the point of PEI to me is to not need to mess with hairspray, glue, etc.. I did try washing it, soap/water and alcohol. I'll have to try it on PETG.
 
A youtube video popped up in my feed the other day where someone recommended a dial indicator to set z-height. I assume by touching the nozzle to the bed, zero gauge, and then raise Z to the correct height according to the indicator.

Searching YouTube for "3d printer z calibration with dial indicator" will get a number of results. I haven't tried so can't comment.

I agree that setting Z was particularly nuanced for PETG on the textured sheet. I had to calibrate a few times in addition to upping temp to 90*C before getting good results. I also often print a 4mm brim to help.
 
I’ve printed 30 or so rolls of Overture PTEG on my Prusa i3MK3S with the textured sheet. I haven’t cleaned or done anything with the sheet in six months or so. Z height is critical, once it’s dialed in right, let it eat.

This is what a good first layer looks like (left side of photo)

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