So, to share some experience on the E3D hot end:
I gave myself a double problem by upgrading both the hot end and the extruder at the same time. The hot end seems to preform really well, when kept within its perimeters. In a bowden setup I see far less oozing (better retraction, less ooze when there is no retraction). This could also be related to using the direct drive extruder (hence the issue in nailing down problems and benefits).
One thing I have been able to identify is the extruder gear and issues relating to it:
I bought the Raptor gear from Qu-BD based on the build specs from Airtripper (whose design I used for the bowden direct gear extruder). The design spec calls for a small bearing to be installed at the end of the motor shaft. The cavity can be seen in picture 1. I received the bearings today and installed it (not pictured). After installing I found that the E3D was jamming very consistently. After many experiments I think the problem came from the newly installed bearing causing the gear to bite too deeply into the filament, causing it to be misshaped. The two cubes in picture 2 show on the left a poor extrusion, which would usually lead one to think that temperature was too low. In fact temperature on the left was 20.C higher (210) than on the right (190).
Picture 4 illustrates the filament after extrusion and the extreme cut in of the Raptor gear, when supported by the bearing. removing the bearing allowed printing to proceed as normal, I dropped temps back to normal range and produced the right hand cube in picture 2.
Prints were done using PLA.
Any other experiences with this extruder gear, Airtripper’s extruder or the E3D hotend greatly appreciated.
Seems to me if you’re getting less tension without the bearing on the extruder shaft, there’s probably twisting and lateral loading on the shaft - not a good thing. I’d put the bearing back on, then back off the adjustment screws on the idler bearing.
I since did an update that no longer supported the raptor gear after l was able to get hold of the MK7 drive gear.
The MK7 drive gear performed far better with less force pressing against the filament; making the axle bearing optional.
The teeth on the raptor gear are too bold and too far apart to get a good grip on the filament, even with a high amount of pressure on the axle.
I use the ultibots drive gear on a direct drive extruder and it’s been very reliable. Because it’s cylindrical you can counteract the idlers pressure with a bearing acting On the other side of the drive gear. http://www.ultibots.com/micro-extruder-drive-gear-3mm-filament/
It seems to be a lot more reliable without the bearing. @Patrick_Ryan that seems to be an obvious solution, but i found i couldn’t slack off the idler enough and have it grip properly. As mentioned by @Mark_Heywood the raptor is very toothy, as you can see in the picture.
I will be ordering a new gear from Arcol.hu. His stuff seems well researched and executed.
Its probably a function of me not using the correct system for tightening the idler - the original design calls for some rubber tubing, but I couldn’t find any so I used springs and washers instead. They slide off the mechanism fairly easily if I loosen them too much.
I installed a 3mm E3D last night on a bowdenized geared extruder. The 3mm tubing they give you is far too small - there’s almost no play for the filament - maybe part of your issue? When I swapped the tubing out, everything was perfect. My only complaint is that it’s about 10mm longer than the makergear it replaced - but that’s a small price to pay for better ooze prevention and higher temps. I’ve only used ABS in it so far. I posted a vid of it printing a cat - the center fan has side ports to cool the E3d.
The 1.75 version (I plan to run both on the big bot) has good tubing, but I haven’t gotten around to installing it yet.
@Paul_Chase Jamming in the tubing? Good thing to keep in mind.
I’m using the 1.75 version. I’m not using the tubing they provided, but there is very little friction inside what I am using, I can move the filament easily by hand. Likewise after a jam if I remove the tubing from the hot end, the extruder can easily retract and feed through the tubing.
I think the jamming is happening in the E3D itself because of the mishapen filament. If I pull the filament out, clip the end, and put it back in it will work for a bit. If I don’t clip the end, it won’t feed into the hotend properly. Removing the small bearing seems to help the situation because the teeth are not biting as deeply. I will be replacing the drive gear, see if that fixes it.
@Nathan_Ryan The 3mm bore on the hotend is fairly loose - there’s definite fattening where the melt zone is when I pull it back out, I measure the bulge at 3.7mm. Maybe the 1.75 is tighter?
Interesting to have basically opposite problems
Also, their heater core - I’m running it at 24V and have to set the pid max to 64 - the heater’s very low resistance.
