I am using repetier and slic3r to print with an mk8 extruder. Somewhere along the line I might have messed up a setting that is causing extra filament to be pushed out. It can’t go out the nozzle, so it is seeping back out the top of the heating block and covering the nozzle. The print seems to be fine up to a point, just a little bit extra filament is being heated up and not all of it can go through the nozzle. Eventually, you can here the extruder clicking as if it is tying to push more filament through the nozzle and then the print fails as it ends up clogging the nozzle with filament.
I just replaced the nozzle with a brand new nozzle and tube and it did it again. About 40 minutes into an hour long print, the feeder starts clicking and no more filament is being extruded.
I double-checked the filament size is 1.73 and the nozzle size is .04. Actually I did change the speeds and feeds to slow the printer down a bit about the same time as this started happening, but you would think that wold e accounted for in the slic3r calculations.
That threaded part and the nozzle are supposed to butt up against each other, and the heat block holds them together. If there is a gap, filament can ooze out the top because it’s melting in that gap, which also makes it harder to push the filament through.
You will need to reassemble the hotend and clean it up as well.
Have a look at my assembly instructions. You have a few issues there. First is the nozzle and the throat must form a tight seal, do this by ensuring the nozzle is not tight to the heat block and has a tiny gap. Second the throat need to be as high into the heatsink as possible or you are going to get very poor prints until it just stops printing.
I’ll just add that, if you want it to be really tight, you should first heat up the whole thing, then get it tight. This way it will always remain secured. If you tighten it while it’s cold, then it might get loose again while hot.
Obviously, use gloves and whatnot to avoid burning your fingers.
Unless of course if you’re into that kind of things.
Thanks for the info. The seeping issue has been resolved with everyone’s input.
However, it is still clogging after 20-30 minutes. I have tried two different rolls of pla. The first few layers work fine.
I have tried 215 and 205 with similiar results.
I am using the default slic3r settings for the most part. I have adjusted the travel speeds and set the nozzle and filament size. I am using a nozzle size of .4 and layer height of .3.
Is it possible my temperature is higher or lower than what it is reading. Any way to check or adjust this?
Took it all apart to clean up. Looks like the filament hardened in the tube this time. Is that an indication that the extruder temp is too high? Or something else?
I’ll try it again and make sure to take some pics if it happens again. Might try a little lower temp as well.
We will need more pictures of your extruder assembly.
Many things can lead to clogging, my bet would be that there is a problem with the cool side, but we don’t see much in the picture you posted.
A properly tuned extruder system should be able to work at any temp (as long as it is over the melting point of the filament, of course). I could set mine at 250 degree using PLA and it would still work fine. Prints would be ugly and unusable, but it would still work.
I’m not a big fan of those kind of extruders. You basically have no cooling, most of it will work for a short time because of the thermal mass of the extruder assembly.
Basically, what I think is happening is that your hot end slowly heats your aluminum extruder block assembly. Then, while printing there is some additional heat from the extruder motor. Combine that together and at some point you reach over the capacity of the assembly to get rid of that heat once the thermal mass limit has been reached, then the plastic melts too high in the threaded insert and clogs.
So you’ll need to mod that thing, either by lowering the current you give to the extruder motor (not sure this will be enough), by adding some fins on the threaded insert and/or by adding a fan to blow on those fins or the extruder assembly. I’d go with a fan since this probably the most efficient solution, this will help you to narrow the issue down easily.
Before you start a fire, please put the thermistor wires under that screw! If the thermistor falls out, the heater will stay on until it reaches temp, and since it can’t read that temp, it will stay on until either the firmware disables everything for safety, or the aluminum block melts, whichever fails first. Usually those kinds of insulated heat blocks have a wrap or two of kapton tape over the insulation to keep it together.
With normal temps 260C and under there are no issues. I run 4 of them 24/7 (literally) with a larger nozzle so I am pushing them pretty good.
What brand of filament? Hatchbox was good at 196, inland 218, makergeeks 235. What speed are you trying to print at? Try 30mm/s, do some small base taller test prints so you can get past the first layer (usually the problem) and see what is going on. Have you ran any other type of material through it and not flushed it enough? In your picture the gear looks really close to touching the heatsink, it should not be. Does your extruder stepper get warm or hot after 20 minutes, What board are you using and what did you set the driver too?
I am using hatchbox now. I have tried 40 mm/s and recently 30 mm/s.
I keep clogging tubes and nozzles, so I have been replacing them along the way. This latest result was from a brand new nozzle and tube.
I’ll need to check the stepper for temp changes, but I haven’t noticed so far.
I am using the mini-rambo board with your marlin firmware with the heated bed and extruder enabled.
I haven’t changed any driver settings.
I noticed the gear seemed a bit too far out too. I’ll make that adjustment as well.
I just found your page that shows the beginner slic3r settings. I’ll make an attempt with my settings matched to that to see if I can get a good print.
Is the fan actually blowing? It should be cooling the fins which cool the extruder block which cools the portion of the throat above the heater block. If that fan goes off for any reason you’ll see this type of issue.
