Filament seeping out of nozzle
Dear friends,
I have been 3D printing with my Prusa i3 MK3S+ for almost a year now and have troubleshooted quite a few problems but this one really stumped me. When I first calibrated my printer, I was able to print Bengine that passed all the tests; problems started about a month ago. Recently I noticed that my smaller prints keep getting unstuck from the bed. I clean with isopropyl alcohol before every print and I tried to rejuvenate the smooth PEI with acetone to no avail. Last month I recalibrated the first layer print and noticed severe uneven extrusion of filament: some lines were thick and some were thin, and the corners of the square were badly curled up. Thinking it's a clogged nozzle, I did 5 cold pulls until it came out without any burnt part. Still didn't help so I bought installed a new nozzle. I notice while heating up, the filament seep out extensively from the nozzle even when the motor is not engaged. Sure, some leaking is normal during heating and but it used to be so little that the initial leveling wipe took care of it. Now, it leaks about 5cm of filament; certainly not normal. Watching , I suspected my problem was moisture. I live in the Pacific Northwest (USA) so it's cold and rains often, but the filament never touched water so I didn't think I need to dry it. I just bought a filament dryer and have dried my Overture PLA at 45 for 4 hours and still the seeping persists. Here are some images of its current state
Curled first layer calibration
Burnt filament dropped on top of print even thought hot end was clean before print
I'm in the process of drying my filament at 50 for 6 hours. Please help me figure out how to solve this problem. I have grown very attached to my printer and this really depresses me. Thank you so very much in advance for your help.
RE: Filament seeping out of nozzle
It's difficult to tell from your photos, but I suspect that your Z may be off a bit and/or you have some leakage around your nozzle.
The first thing I would suggest would be a rigorous Z calibration using one of the multi-square test prints such as the one below.
I would suggest tuning the Live Z for the best 'squish' on the center square and then carefully inspect the outer squares and tweak the front/back and/or left/right, if needed, so that they all come out the same. There should be no 'curl up' at all on those squares.
Again, kind of difficult to tell what it is from the photos, but it looks like your build sheet may have some uneven residue on it. (It may be the coating that looks like dirt in the photos.)
I'm not going to admonish you to Clean Your Sheet And Clean It My Way (tm) but be sure that there are no particles on the sheet. It should be clean and smooth.
A good sanity check for a partly-clogged nozzle is to manually extrude some filament slowly. Inspect it carefully. It should come out straight down with a circular cross section. If it consistently comes out at an angle and/or the extrusion is not circular, you probably have some crud in there. Heating the nozzle up and pushing some cleaning filament through it will usually do the trick. Also an accupuncture needle can be used, inserted upward into the nozzle, to help break up scorched filament residue.
I would also suggest checking for leaks around the nozzle and hot end. Brown 'boogers' dropping on the print can be caused by leakage. There should be absolutely zero evidence of molten plastic coming out of the hot end anywhere but the nozzle opening. Remember that there is a certain degree of pressure in the hot end, and if there is a leak, the molten filament will find it and ooze out.
A small amount of oozing out of the nozzle opening can be normal, and seems to be more common when using PETg filament. You might want to get in the habit of using a soft wire brush on the nozzle area before the print, with the nozzle up to print temperature.
RE: Filament seeping out of nozzle
Thank you so very much for your response. I'm getting a new PEI sheet because indeed it's uneven with a rigorous check. And you're entirely right about leakage. I'm reassembling the hot end to make sure the heat block is clean as well as proper contact between the heat break and nozzle. How do you access the multi square print? My first layer calibration setting has only one square.
RE: Filament seeping out of nozzle
You dont access a multi square, you slice and print it as with any other normal model.
The built in one is basic and a lot of us don't bother with it any more once its been done once to lock in the basics. Many use the Jeff Jordan 75mm square technique to get a good live z value for each sheet. Others like JSW will use other calibration patterns. There's hundreds of them available to download. Just grab one, size it for your printer bed (if needed) and slice.
By printing a larger one you can adjust the live z while printing so you can tune it better. The multi areas ones allow you to see variances in the print bed.
Don't forget though that heat changes mechanical tolerances at this level so its always better to preheat your bed for 10 minutes before doing a calibration and also before a print session. This ensure repeatability. Doing a live z from a 'cold' start will give different values to doing it on a preheated bed where the machine has had time to expand to temperature.
RE: Filament seeping out of nozzle
There are several versions of this floating around.
I think this one came from the prints section here, and rather than make you hunt for it, here it is.
RE: Filament seeping out of nozzle
@ Illmilliner
I ran across this post and I am having the exact same problem with my MK3S. I am having the same problems as in all your pictures. I used to have it dialed in great then all of the sudden this problem started. I was wondering if you ever figured out what was causing it?
I look forward to your reply.
Thanks