BMG Extruder Carriege for Prusa i3 MK3 Short and Bearing Version

by drodfro Nov 29, 2018
Download All Files

Thing Apps Enabled

Please Login to Comment

Any chance that you could modify this so it fits an 18mm inductive sensor? I`m a bit rubbish with cad

Price Question: What's the offsets you used for the Pinda sensor?

The description is really confusing. There are so many versions in this single Thing, I can't decide which one I need.
What I know is that I'm building a Bear (2040 frame) upgraded Prusa i3 MK3S clone.
Do "Bear short" and "Bear bearing" refer to the Bear (2040 frame) upgrade? What's the difference between short and bearing?

Comments deleted.

Which version of the firmware shall I burn? I think I have an issue with the z height and pinda for calibration. I printed the short bear version.

can you make an update for the new MK3S sensor?

do you have an update for the new MK3S sensor?

do you have an update for the new MK3S sensor?

I made a new one with the mk3s extruder body and modular sensor to fit mk3 and mk3s. And I also have the mmu2s module ready but haven't tried it yet. https://www.thingiverse.com/thing:3510052

If you don't want to print that one, the bondtech solution for mk3s sensor that works with their bondtech upgrade should work with this design.

Keep in mind that the new design needs a pancake stepper.

Bondtech BMG MK3S and MK3 DissEd
by drodfro

Hello, this is compatible with BLTouch sensor??
And what stl is for prusa i3 steel?
Thanks you very much

I printed this and have it setup. The e3d v6 hotend wires don’t run out the back as the heater block doesn’t fit in that orientation with the blower fan? And it appears the nozzle is too low, and the blower fan is blowing directly on the heater block instead of the nozzle. Am I missing something here?

Also I believe the blower fan can be made closer to the nozzle with the full size stepper motor. I’ll remix it once I figure out why My hotend isn’t aligned properly with the fan.

Heater block fits in that orientation and wires come out the back just fine. Haven't change that part of the design, so everything is exactly like the stock prusa extruder carriege. You can look up the prusa manual to place the heater block as shown in the pictures. The blower fan is again like the stock mount. It doesn't blows on the heater block from the sides for sure, don't really know if it does from the front, you'll have to trust prusa team for that because it is like the stock carriege. There are other blower fan designs out there that you can't try, and since that part is untouched, they should work.

*With the extended blower the air direction is different as you lose the inclination however, I've been printing with it for a long time and it works fine, but the stock one (the one that requieres a pancake to fit) probably works better

So it seems the e3d v6 clone is a bit longer, and is the reason why the heat block is lower than it should be on mine. I didn’t like the idea of the cabling being bent at a 90 degree angle and presumed the thermistor wires ran straight out the back- I can see the counter argument for keeping it in this orientation as well.. Sourcing the proper size bolts was also difficult. Overall it worked well enough with igus bushings, though I wish I had printed it solid (particularly the middle piece between the bearing holders and bondtech bmg) as getting proper tightness on some of the bolts was difficult without breaking some parts where the nuts go.

The only room for improvement I can see is moving the blower fan closer in the large motor design. And maybe one more bolt that helps secure the bearings holder section with the front part I mentioned.I am being stubborn and sticking with my full size moons motor. In hindsight I might have been better off getting a genuine hotend.

Thanks so much for the response and great work!

Any chance you could make another model just with a mount for the BlTouch instead of an inductive probe?

Comments deleted.

What is the difference between the different versions? I'm a bit confused by them, zaribo, bear, short, bearing? zaribo and bear I can figure, but what are short and bearing? Sorry, only been in this a couple months, lots to learn. thanks.

Will the stock stepper motor fit this design? From the pictures I've seen of people's makes, they're all using pancake motors and there isn't a lot of clearance between it and the part cooling fan arm.

It does fit. I am still using the stock motor and works great but will change it eventually for a pancake. Just less weight is sufficient reason. You need a different fan arm and fan shroud with stock motor. They're named accordingly.

Excellent! I'm wanting to pair the BMG with a Moons' motor (for maximum overkill) and was concerned it wouldn't fit. I'll definitely post a make once it's printed and assembled!

Comments deleted.

Sometimes it is very hard to put the filament in. The filament must be bent to the left to work. This will not work with the MMU2.

I thing because we don't have clip to hold PTFE tube to get it straight. Sensor cover will not work with MMU 2, I print it and don't know how to put it in.

There is a sensor cover for mmu in the files

I'm using v1 with a MMU2 and it's working great. Did something major change with v2?

No. The stock versión has the same filament sensor position, same exit hole, same everything. The filament is feed straight, not bent. I'm not sure which version he has but you shouldn't need to bend the filament in any direction. Maybe some pictures of his assembly could help identify the problem

Can you help me increase "Fan_Holder_prusa_motor_DissEd" and "fan_kepping_prusa_motor-DissEd_v2" for 48.3mm long motor ? Prusa motor is 40mm long.

Do you still need this? I have been out a while and did not pay much attention to thingiverse

I'm not sure if this is intentional or not, but one of the holes for the screws that holds the motor does not go all the way through on the extruder body. It is the same on both versions. Also, while it doesn't show on the stl, there is a flaw on the underside of the filament sensor portion of the extruder body. It is as if there was a hole that was not properly covered. Pictures attached (I think)

Push that cilinder from the other side. It is a support. The filament sensor thing is not a flaw, it is a 0.4mm wall and it's hard to print. It doesn't need to be perfect. No light is gonna get inside

So I'm guessing that we need longer screws to attach the bondtech to the carriage. What length?

I used the longer ones provided by prusa. M3x40 I think.

Removable/changeable mount for the pinda would be great. Mine are slightly getting a sag because of long exposure to heat. So now I have to print a compete back part and dissasemble the extruder to replace it. Would have been much better to mount the pinda mount with screws.

Great work though.

Just completed my first test print. WOW, results look really good! Much better than the Prusa extruder. Filament sensor seems to be working well so far, but I have not put the MMU2 back on yet.

Hey, awesome work!

I'm only having one issue and that's any type of blockage in the PTFE tube in the Extruder and you have to take the whole thing apart since the BMG holds it together.

I have no idea if this is something that can be worked around to make it easier to take off and clear but it would be very nice. Again, great job and I absolutely love it!

You take the extruder body. It works like mk3 stock extruder in that way. I don't think there is a way to do what you suggest, but ey! step files are there and maybe someone has an idea to make it work

Am I missing something or are there no sensor covers that work with the MMU2?

I'll upload it but don't know if it works. I guess you would have to take the metal insert from the stock part.

Got mine assembled ok, haven't printed anything yet, but was able to load & unload filament successfully. One thing I found is that the filament sensor is just a tiny bit too tall for the chamber, and sticks out the top maybe 0.2mm or so, which prevents the top cover from sitting flush. I'll probably just carve a bit of plastic out of the underside of the top cover until it sits flush.

The chamber is the same size as stock. I think the problem is the 0.4 mm wall being one perimeter doesn't print great and may create something that rise it those 0.2mm. You probably can cut it out for the most part. No light is going in with the bmg and the screw is what keeps the sensor in place.

So we don't need these parts from Bondtech ? And just put the PTFE tube inside, and any information how long the tube should be ?

That's right. You don't need those. Mine is around 8.5mm, but I would do what I did, put the ptfe inside making sure it goes all the way in and mark the cut. Or try with 8.5mm. It should be the same. I also used a screwdriver to widen the ptfe once in place. Before installation with just the extruder body and the bmg(with the ptfe) get some filament in and out a few times and it shouldn't move anymore getting a clear path. If it's done right the pfte stays inside and it's hard to remove it

Honestly, I'd suggest longer than 8.5 mm length on the PTFE tube. Mine was a little short when I cut to those dimensions.

That black part shouldn't be there. look at the pictures I posted and the image irawans uploaded

Yeah, I realize that, haha. I should have taken a picture after I removed the black part. It still sits about 2 mm lower than the top of the copper ring, which I would think is too low, no?

Great, thank you for the information

Does any of you guys use that with the Bear? If so with which version of the X axis parts? 0.5 or 0.6 Alpha?

I do not believe this will work for the MK2/S or the MK2.5. There is no arm on the x-carriage to trigger the end-stop for the x-axis. Otherwise it assembles really well.

Has anyone tried this with the MMU2 yet? I'm thinking of giving it a go as soon as I get my Bondtech extruder put together, but not sure if I should try it without the MMU first.

Sounds quite promising - but I am not quite sure I understand all the details from the README.
What's the difference to the https://www.thingiverse.com/thing:3165551
What's the short and what's the bearing version?
What are the non-printed parts that are needed?

Bondtech BMG Extruder Carriege for Prusa i3 MK3
by drodfro

The difference with my previous design is in the description.

  • The distance from the filament sensor to the bondtech gears is smaller. The idea is that it might work better with mmu 2.
  • The door or lever of the bmg now opens enough to look inside in case you need to fix something.
  • Some weight loss, but not a lot.
  • Added versions for zaribo and bear.

The short version is the redisign from the previous one and the bearing version is using the indirect filament sensor mod by martin_au. This mod and all needed parts are in his thing. I uploaded this as a remix of his thing and mine and intentionally didn't explain whats needed for that mod to work so people would go to his thing and find out there. I guess it is not clear in the remix tab so I'll put the link in the description as well.

Ah, OK. Thanks for the explanation!

Comments deleted.

Thanks a lot for sharing the design. The filament sensor that you mention is this one, right ? https://www.thingiverse.com/thing:3223513

Prusa Mk3 indirect filament sensor for all filaments (transparent, black, shiny, whatever).

Yes. I made this a remix so in thing details, to the left there is a remix section with the links to his thing