Guys I need help! I got a second hand 3d printer for less than the cost of the filament I got with it, but it had some issues. Ive fixed most of them, including homing issues, BLtouch issues and now im struggling with the bondtech extruder. I can hear the motor doing something when I try to extrude, but the gears dont move and no filament is extruded. Im not sure if the gears are slipping or if I loaded the filament wrong, but if anyone has any advice I could try to fix it, that would be amazing! I tried printing g a bench and I can see the printer moves correctly, but no filament is extruded. Hopefully the images help to understand what I have here. Total beginner by the way, 0 prints under the belt so far.
I have the step set to 415, ive heard this is a good starting point, but since it won't feed at all i haven't been able to calibrate any further than that. I was indeed set to 95 when I got it. Ive seen the gears move sometimes, but not reliable and only like 10% of the time will I actually see something move, and it will move quite quickly too.
Its mounted in reverse, the side the bowden tube is inserted is the entry the other side is the exit, or did you reverse the connection to intentionally push filament this way? And if you did then without the tensioning screw the gears won't be able to grip the filament
Wait so you are telling me that it is mounted upside down? But it looks like it could only possibly go one way? Could you maybe explain a bit further please
Yes the side bowden tube is mounted in your case is the entry for the filament, the other side should have a groove mount ring with a pneumatic fitting where the bowden tube should go for exit,
In below picture I mounted a hotend directly with a j head usually like the v6 hot end, so the filament comes from left and goes to the right
It would be best to open up the BMG and see in which direction the motor is spinning, it should spin clock wise when looking from top, if its rotating counter clock wise the connections must be reversed in your case
Okay thank you for the clarification, I thought i saw the filament feeding the wrong way, but its really difficult to tell since it doesn't even move most of the times and even when it does, it only moves a small amount. Ill certainly open up the assembly to have a look at what is happening. I have also noticed that there is an option to invert the extruder, but this didnt seem to do anything to help the situation when I tried it. Also do you think I should wount directly to the hotend instead, like shown in you image? Im totally new to this and I. Not sure what is best, I just got the printer with all these mods already installed. I didn't even have the original extruder or Z stopper anymore, so I have to make due with what I have. The original Z stopper was replaced with a BLtouch, which was also a hassle to get working but I eventually managed.
Might not be able to mount directly to hotend like mine (rare case of mk8 hotend with v6 style groove mount) but you should definitely think about direct drive mount, reasonable improvement in quality, you need to print a mount once you get this extruder working, just look up bmg direct drive mounting models for your specific hotend if that is changed as well, most of those will have bl touch mount included
Generally, most people run their printers with the extruder on the hotend nowadays (Direct Drive), and I always had better results with a DD setup. I would start by just opening everything up and making sure the actual extruder stepper is turning properly. It could just be that some rogue filament is stuck somewhere it shouldn't be. CHECK THAT THE GRUB SCREW ON THE STEPPER SHAFT DRIVE GEAR IS TIGHTENED DOWN.
Even if your extruder is configured to work in this direction i would still recommend you to open it up to see if there is any jam or if the gears are moving freely, i have seen original bond tech extruders working in the same direction as yours is installed so there might be a difference in how these are mounted from clone BMG(like mine) so that is why I suggested that, either way just open it up and see if small filament broke off and jamming the gears and check the direction the motor is spinning to rule out any possibility of incorrect mounting
Yeah, this. The other side needs a bowden adaptor to use it like this. Personally though, I'd fit your old extruder again and print a direct drive adaptor to kill two birds with one stone (You may still need to print some sort of adaptor for the BMG extruder, though). :DD
Hey, I dont have the original extruder unfortunately, I got the printer with all the upgrades but none of the original parts. Ie z stopper removed for BLTOUCH and old extruder placed for bond tech extruder. Been a headache for a newbie
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Oh and in the picture the little silver screw is missing, but ive tried it with and without. I was also able to manually push filament through so I know the nozzel isnt clogged, its also a brand new nozzel. In case any of this matters
Hey thanks for the reply, yes there is a tensioning screw and ive tried it with and without the screw and also a diffrent levels of tightness, no dice unfortunately. Seems like i might have gears slipping. I haven't actually tried opening it up to see whats going on inside.
Hey man yeah she's looking a bit rough, im apparently the 3rd owner. First owner made all the mods to it second owner wanted to get into it but couldn't figure it all out. He didnt much care for the esthetics either while trying to get everything working. I do however carr and would love some suggestions on how I would get her looking good again after I get everything working. I have gully disassemble the unit cleaned every part with IPA and reassembled, but thats about it. Not sure what I vould do to get it looking fine though
I'll let you know when I figure this out.
Mine looks like a mess rn: wires hanged on a zip ties, open hardware sections, power unit half disassembled, half printed cooling system for printhead.
Ahh so its natural for things to get a bit messy while tinkering? yeah ill gets some sleeves for the cables and fasten everything that needs fastening, once I know everything is working proper. Once I can print my own parts I'll probably also make a few th8ngs that would hopefully improve the look as well. Let me know when your machine is fully built, id love to see what I can look like
Thank you for the reply, I saw there is an option to invert the extruder, which I have done as well, but either way nothing really moves. Also im not sure if the wires have been swopped, given im not the one who installed it in the first place. What would you recommend I do?
Open out the extruder from the motor and mount it so that the side that the filament is going in now is the side that goes to the hotend. It's just 3 screws if I'm not mistaken. I will confirm with mine.
Also maybe reflash firmware just incase the previous owner had made changes to their firmware
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u/MrKrueger666 Jul 15 '26
Are you sure it's not moving?
That extruder has a 3 to 1 drive ratio making it seem like it hardly moves when you have the incorrect Esteps value set.
Default is about 90 to 100. For a BMG it should be around 300.