Perplexed! It seems as if the filament (3.0mm, PLA) is slipping when it’s being fed through the extruder. I’ve disassembled the extruder assembly a number of times AND have verified that the filament will feed when the hotend is removed. In fact (with the hotend removed) I have tried to hold the filament while turning the large gear: there is simply no way I can hold the filament! However with the extruder assy attached the filament just seems to slip. Initially I had issues with the stepper motor but have since adjusted the calibration voltage to 550mV AND made adjustments to the motor gear position to ensure smooth operation. Mechanically it everything is just swell BUT the filament just doesn’t feed with the hotend attached
Any ideas? I have screwed the nozzle on TIGHT
Aside. I have adjusted the hotend temperature in the software. I have the revised hotend with the larger thermistor running through the heater block. I surmise the fibreglass sleeve over the thermistor provides some thermal insulation: I needed to change the temperature setting in the software to 175 deg in order to get the actual temperature of the heater block to 190 deg. [Interestingly I needed to raise the software setting of the bed to 60 deg in order to achieve an actual temperature of 50 deg on the digital thermometer].
Repeat. The filament will feed when the hotend is removed - if I try to hold the filament and turn the hobbed bolt via its gear wheel I can not hold the filament. However the filament feed slips WHEN the hot end is attached.
The stock hobbed bolt is not that good.
It worked with the stock hotend. After i switched to a E3D (All-Metal) my Filement started to slip on the bolt because i needed more pressure to print with my new hotend.
I used a cutting disc on a dremel drilling machine to get the teeth sharp. Works really nice, now.
I already described how i did it: viewtopic.php?f=53&t=13204&start=15#p58249
Unfortunately, i did not take pictures. But it’s quite easy.
If you don’t want to try that out, you can buy a better hobbed bolt. It will cost you about 5-10€.
I advice you to try it. Worst case szenario: The hobbed bolt that already doesn’t work properly could be ruined.
[quote=“cantax”]The stock hobbed bolt is not that good.
It worked with the stock hotend. After i switched to a E3D (All-Metal) my Filement started to slip on the bolt because i needed more pressure to print with my new hotend.[/quote]
Thanks for the input. Having more-or-less just completed assembly I’ve spent the last three days investigating why the filament feed is slipping. N.B. This complaint pertains to the stock standard extruder, heater, nozzle, and original software and settings, etc.
The filament delivery path is clear
I removed the heater block and nozzle to check the measured delivery through the hotend; I get exactly the required length of filament feed. As soon as the nozzle (and heater block) is reattached is when problems start. N.B. While holding back the spring I can manually force filament through the hotend.
There IS a lateral shift of the hobbed bolt assy (away from the tension spring) by approx 1mm: this is because the bearing rebates have a slightly larger diameter than the bearings themselves. Having said that there ARE teeth marks on the filament.
I have tried various software settings to no avail.
Hey Velleman! If popular opinion advises modifying/replacing the hobbed bolt surely this constitutes a warranty problem. How about stumping-up for an upgraded extruder and hotend assembly because obviously this one is…
I’ve been having the same problem with the slipping. I was considering a hobbed bolt with the semi circular cutout in the profile, but I think something else might be the real problem. I was thinking it may be possible the fan is cooling the hotend down (as many other’s have advised here), and while there is enough power to keep the hotend hot with the fan blowing on it, it is taking the thermistor too long to play catch up and tell the hotend to heat up.
Can you print? If you don’t have a nozzle for the fan, that keeps the air away from the hotend, that might help. I think what is happening is that the plastic liquifies in the hotend, but if it has to go too fast, or gets air blown on it, it cools down and the plastic starts to solidify, making it harder for the extruder to shove the filament down the hotend. Like how it is difficult to squeeze the glue out of a hot glue gun before it has completely heated up.
I’m going to try the nozzle, and also to try a dab of thermal paste for heat sinks down in the hole the thermistor goes in.
For you, is there any way to stick a thermometer probe inside the nozzle, and check the temperature? Barring that, have you tried a hotter temperature? Some of my PLA will print at 190 C, but I have some white stuff that won’t work unless it’s 200 C, and black that needs 210 C.
And dumb question, is your wingnut on the spring on the extruder tightened down, and does the bearing the bobbed bolt pinches the filament against, does that turn smoothly?
For the higher temps for the white and the black.
This almost sounds like it is ABS.
The nozzle for the fan is a very good idea I did that for mine.
I also mounted a second fan on the other side for even cooling but also had to readjust it so it didn’t blow on the extruder.
I know you did this but I will ask anyway.
In the instructions “Building the Extruder” there are 2 bolts you need to file down.
Did you file them down enough?
When I was building my second printer I didn’t and the pressure bearing was not engaging enough.
You should also check for proper mounting in the thermistor.
I have had problems with that in the past.
For the higher temps for the white and the black.
This almost sounds like it is ABS.
The nozzle for the fan is a very good idea I did that for mine.
I also mounted a second fan on the other side for even cooling but also had to readjust it so it didn’t blow on the extruder.
I know you did this but I will ask anyway.
In the instructions “Building the Extruder” there are 2 bolts you need to file down.
Did you file them down enough?
When I was building my second printer I didn’t and the pressure bearing was not engaging enough.
You should also check for proper mounting in the thermistor.
I have had problems with that in the past.[/quote]
Thanks for the ideas.
The white and black aren’t ABS, they don’t smell when they melt. But, they might be harder, or smoother/ more slippery than the other colors of plastic, making it more likely to slip and under extrude?
I will take the extruder apart and check the height of the bolts. I filed them close, but they might not be 100% absolutely flush with the plastic. However, filament that I pull back out of the extruder is has significant indents from the hobbed bolt pressed into it, so there is plenty of pressure. The pressure bearing doesn’t hang up on anything.
Forgot about this thread and posted a new topic, but it addressed this ongoing problem: I believe my filament was slipping and the hobbed bolt grinding into it, because there was some gunk in the filament pinch bearing, that made it spin sometimes, and get hung up other times. It wasn’t until I took the part out and was idly spinning it by hand, that I discovered the problem.
This seems to be a recurring topic which never seems to get fully addressed. I have been struggling with this problem since day 1 (about 6 months ago) and still cannot print consistently good parts despite trying all of the suggestions. Can anyone give me a set of speeds, feeds and temperatures that work for them consistently. I have tried various combinations but still have problems. I have seen a video on youtube where he is running at 80mm/sec but I cannot run as fast as 25mm/sec, how is he achieving this?
