Material just flows from nozzle 🙁
Hi,
I got some strange issue, that I was thinking related to specific material, but later noticed, that it affects almost everything - when printer is in standby with active heater (after inserting new filament or after ending print) a lot of filament just drips off nozzle. As a lot I men, let's say I force extrude 5mm of filament, then remove that from the nozzle and in next few min another 10-20cm of filament just flows out 🙁 That is same for all range of materials, PLA, ABS, Nylon, Carbon Fiber, PETG, etc
My guess is that there might be some air leek between hotend and nozzle, so some filament is just getting out; however, if after I wait that leak ended and then change material, there is still lots of old material that come out before I see new material. That give me idea, that there is some leakage in the middle of that construction and I was thinking, that something went wrong where I plug nozzle.
I am planing to replace whole hotend with nozzle; however, I wonder is there is other solutions, or I am fully off with this issue ?
Alexander.
Re: Material just flows from nozzle 🙁
This is pretty normal, at least if by "10-20cm" you mean the length of the string from the nozzle. Gravity always wins 🙂 The only way to prevent drooping during print is retracting. This is not pulling the filament out of the hotend, its mostly about creating negative pressure. That helps for a short while (usually enough for the nozzle to move to the next spot), but its not gonna stop oozing if you leave the hotend hot for several minutes.
Re: Material just flows from nozzle 🙁
its mostly about creating negative pressure
You can only get negative pressure if the feed line has a perfect seal; which it does not. The filament is 1.75mm diameter, passing through the PTFE and heat break which has a diameter of 2mm. Retraction can help but only for a very short period of time (maybe a second or two).
So no matter what you do, you will always get oozing. Best thing to do is to only bring the nozzle up to operating temperature as you start to print. The 9-point calibration can be done with the nozzle at 170 degrees; before that and after the print has finished, all you can really do is to keep the extruder heater turned off.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…