Holes in Prints that don't seem to be made by moisture
 
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ColsonBaker
(@colsonbaker)
New Member
Holes in Prints that don't seem to be made by moisture

Hello fellow enthusiasts! I am relatively new to printing and am facing some issues with my prints.

Printer used : Prusa Mini+ (kit)

When I started out, I printed the Buddy gcode bundled with the printer and found some holes up and down the prints. (Brown test Prusament used, stock PLA settings : 210 nozz, 60 bed the other settings were stock too) I did some digging and found that it might have been due to moisture and the filament had been sitting out for some time. I live in a country with an average 70-80% humidity. So I bought myself a filament dryer and tried it out again.

I tried on 2 brand new filaments the 2 Buddy prints again from the USB :
1 Generic Black PLA & 1 Generic Orange PLA-F




As you can tell from the photos, the holes are consistent at where they are placed. Throughout both the models, they seem to occur at the legs, the back, the face and the tail. (Ignore the Buddy that is in half because I was messing around with the live Z height to see if that affected the holes. It didn't.)

My settings for each filament :
Black PLA : Nozzle : 200c Bed : 60c Speed (on printer) : 90 Nozzle flow (on printer) : 95
Orange PLA-F : Nozzle : 220c Bed : 60c Speed (on printer) : 110 Nozzle flow (on printer) : 100

So it cannot possibly be a filament problem right? I dried both filaments at 50 degrees for more than 2 days, kept them in ziplocks with desiccants. If they were filament issues, the holes would be more consistent? Could it be a retraction issue? I thought that it might, so I slowed prints down, turned the heat up and down to test and see, but none of which gave me any better results. I also noticed a popping sound whenever I printed using whichever filament, dried or not dried. The purge line would have that then throughout the print whenever a little blob is on the print and gets ironed over, it will make a popping sound too, from what I observed.

Video with sound here

When I printed a Benchy on the black PLA, it gave me an almost perfect print, save for the crazy stringing and the holes in the cabin.

Nozzle : 210c Bed : 60c Speed (on printer) : 100 Nozzle flow (on printer) : 95

Most of my settings were on stock and not messed around with. Neither were the gcodes as they came from Prusa's USB bundled with the printer.

However, a Triceratops skull which I took off Prusa Printer's site printed on the PLA-F perfectly with no pits anywhere.

Nozzle : 210c Bed : 60c Speed (on printer) : 90 Nozzle flow (on printer) : 95 Infill : 15%
Supports auto generated

So most of the issues tend to occur on the bundle gcodes with Prusa. I printed a bunch of wall art and they did not have holes, neither did the Triceratops. Do the gcodes have retraction issues that are prevalent? Or are the seams not set well? I am unsure because it seems some people do have issues with them but not the same as I do.

First I thought that it was moisture related, which has been proven to not be (dryer, desiccant, new filament etc). Retraction issues are possible but even on Prusament filament it seems to give the same issues, and even when speed is slowed, it still pops and has holes.

While researching on how to do a cold pull because I wondered if there was a clog, I realised that I did not calibrate the SuperPinda on the heat bed. Instead I placed the sheet on the heatbed before I adjusted the height. Could this also be the issue? I am at a loss and its been a couple of weeks trying to iron this out. Any help would be great!

Thanks guys.

Posted : 17/07/2021 6:22 am
JoanTabb
(@joantabb)
Moderator
what is the purpose of this title field? It doesn't show in the forum, but the forum software refused to accept posts without a useless title

I don't have a mini...
From the bottom up
On the Mk3, XYZ calibration is done with the   build plate off the printer, so that the supapinda can 'See' PCB PADS etched into the surface of the heatbed.
Live Z calibration is done with the build plate in position on the heat bed.
I believe Mini calibration is similar... 

the pre sliced models are sliced so that you will have something that will print, is is possible that the settings are not exactly ideal for your printer. 

As your triceratops printed without issue, when you sliced it, I would not worry about trying to make the pre sliced models print better.  I would get on enjoying the hobby. 

You might consider slicing the Buddy STL yourself, and see if you get a better result!
I just got on with my own prints after a couple of test prints... 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 17/07/2021 9:59 am
ColsonBaker
(@colsonbaker)
New Member
Topic starter answered:
Thanks!

Hey Joan! Thanks for the reply.

I will go fix the Superpinda and recalibrate first layer, and then slice the Buddy file and see how it goes. Thank you! Hopefully I don't have to do any cold pulls or the likes so soon... 😕 

Posted : 17/07/2021 11:49 am
fuchsr
(@fuchsr)
Noble Member

From the pictures the holes looks like random Z seam positioning to me. Easy to test, just reslice with Z seam set to anything but random or with using paint-on Z seam.

BTW, the triceratops looks GREAT!

Posted : 17/07/2021 11:56 am
ColsonBaker
(@colsonbaker)
New Member
Topic starter answered:
Reply

Thank you! Is it normal for the purge line to have popping sounds and that sound occur throughout the print? Or is that mostly retraction related to the gcode sliced by Prusa? I haven't noticed any popping while printing on the Triceratops that I recall

Posted : 18/07/2021 2:32 am
fuchsr
(@fuchsr)
Noble Member

Popping sounds speak for filament that has absorbed too much moisture. You said you live in a region with high humidity, so it may indeed not take long for filament to pick up all that moisture. Try drying it longer. At the 80% humidity level you mentioned I'd print directly out of the drying box with a long PTFE tube. And keep the spools in a humidity controlled environment. I use large Ziploc Weathershield storage boxes ( https://smile.amazon.com/gp/product/B00MWTJXHS/) that can hold 10+ spools, combined with renewable mini dehumidifiers ( https://smile.amazon.com/dp/B00LVN7BM0/). As long as you keep an eye on the color of the dehumidifier and recharge it as needed every month or so, I have had filaments in there for more than a year with no apparent degradation in performance. It's not cheap though, there are other options, but this one has worked for me. I currently use four, with about 45 spools of filament.

Posted : 18/07/2021 2:41 am
ColsonBaker
(@colsonbaker)
New Member
Topic starter answered:
Reply

I see. But I've been printing directly out of a filament dryer box, kept at 50c & around 20-30% humidity. I only don't use the long PTFE tube. My box can keep 2 regular spools inside. I noticed the popping usually comes from little blobs left on the surface of the prints and when the hotend moves over it

Posted : 18/07/2021 6:10 am
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