Another "how to prevent the blob" question
I have two printers, an MK3 and an MK3S. Both printers are working great and for the most part printing everything fine. But there is one exception.
I'm printing a large, flat model that takes up about 3/4 of the build plate. The print comes out perfect on the MK3. But using the same model on the MK3S results in a blob forming on the first layer about 2/3 of the way into the first layer. The only difference between the printers (besides MK3 vs MK3S) is that I have a Micro Swiss plated nozzle on the MK3S.
The other strange thing is that if I print something similar that is just about 15% smaller the print comes out great with no blobs.
Any thoughts on how to prevent the blob in this case?
RE: Another "how to prevent the blob" question
So what happens when you swap nozzles between those two machines. Would at least eliminate that factor from the list of possible culprits?
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: Another "how to prevent the blob" question
So what happens when you swap nozzles between those two machines. Would at least eliminate that factor from the list of possible culprits?
That's not a bad idea, but I try to avoid changing the nozzle if at all possible. I hate that process, and it always takes several prints to really get it dialed back in after a nozzle change.
I actually have another Micro Swiss nozzle for the MK3, but I am waiting to install that until the upgrade parts for the MK3S+ arrive.
RE: Another "how to prevent the blob" question
A blob forming on the 1st layer can indicate a few things:
- If your Live-Z is a little low, the nozzle drags through the filament and it eventually collects into that blob that drops off randomly. This is a common problem when switching to PETG filament from PLA. PETG doesn't need as much "squish" on the 1st layer.
- If the Live-Z is too high, the extrusions won't adhere and can snag the nozzle.
- If bed adhesion is poor, extrusions can come loose or you might get some warping and lifting in corners that lets filament lift and snag the nozzle. This usually indicates you need to clean the bed. For larger parts, you might need a brim and or mouse ears in corners.
These would all explain why it's a problem on one printer and not the other.
If the Microswiss is a different nozzle type compared to the other (e.g. hardened steel vs brass), you might need to bump temperatures to get good adhesion.
Can you send a pic of your 1st layer on the Mk3s?
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RE: Another "how to prevent the blob" question
A blob forming on the 1st layer can indicate a few things:
- If your Live-Z is a little low, the nozzle drags through the filament and it eventually collects into that blob that drops off randomly. This is a common problem when switching to PETG filament from PLA. PETG doesn't need as much "squish" on the 1st layer.
- If the Live-Z is too high, the extrusions won't adhere and can snag the nozzle.
- If bed adhesion is poor, extrusions can come loose or you might get some warping and lifting in corners that lets filament lift and snag the nozzle. This usually indicates you need to clean the bed. For larger parts, you might need a brim and or mouse ears in corners.
These would all explain why it's a problem on one printer and not the other.
If the Microswiss is a different nozzle type compared to the other (e.g. hardened steel vs brass), you might need to bump temperatures to get good adhesion.
Can you send a pic of your 1st layer on the Mk3s?
Thanks Bob. My first thought when this started was that the live Z height was too close to the bed. But I've found if I try to back it off then the first layer doesn't stick well. I always clean the plate with 99% IPA before each print and every other print I do seems to print fine. It's just this large one with very long travel layers that gives me trouble.
Attached is an image of a different model I took while trying to raise the live Z height. It did not go well. Lowering the Z height resulted in the lines sticking better again and printing well.
RE: Another "how to prevent the blob" question
If the Microswiss is a different nozzle type compared to the other (e.g. hardened steel vs brass), you might need to bump temperatures to get good adhesion.
I forgot to say that the Micro-Swiss nozzle is a nickel plated brass. Is your advice to raise the nozzle temp just for hardened steel or would that apply here? I'll experiment a bit with raising the print temp to 245C (PETG). Bed temp is 75C. I also think the retraction settings might need to be adjusted slightly with this nozzle because I am also seeing more angel hair stringing than I did with the stock brass nozzle.
RE: Another "how to prevent the blob" question
@buckeyestargazer
I use MicroSwiss nickel plated nozzles on my Prusa printers and run with the same temperature as brass nozzles.
Have a look at my models on Printables.com 😉