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Prusa Bear-BMG fusion (indirect filament sensor) for MK3 / MK2.5

by MarcoZ76 Dec 2, 2018
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Any chance this will work with zaribo X ends?

Bad news ;-) i tried to open your step file in solidworks but i had some error. can you send us a new one step file or your original 3d file ? Thanks

Hello ! realy nice extruder !! Maybe could you make a variant compatible with BLtouch ? it will be perfect for me.

Hi, thanks! i'm sorry but i don't have the BLtouch so i can't do it.

Hey Marco, love the design but I have a minor suggestion. On page 7 of your instructions there's a nyloc nut in the center, I suggest you move the nut to the Extruder Bottom side and screw to the Top side so the extruder can be easily disassembled without removing it from the X carriage.

Thanks for your suggestion, very appreciated! I will look on it.

Is it possible to use the Extruder with the Zaribo Carriage?

No, i’m sorry. The position of screws on the back carriage differs from Zaribo.

First of all great design putting together the indirect filament sensor with bmg extruder!

I printed all the parts and came out great but do I need the Push-Fit Connector if do not have a reverse bowden setup? It slipped my order for the bondtech materials and I think it will work without the push fit ...

Thanks! Yes it can work without the push-fit connector. Otherwise i have a body design with the PC4-M6 connector.

Actually I've read about the benefits of moving the filament roll off the frame and I started printing an filament holder. So please share the extruder body with the PC4-M6 connector as I can find those for same day delivery at my location. Thanks!

Hi! i upload a version with PC4-M6.

For now I prefer to keep it without a reverse bowden system as my filament roll is on the original support on top of the printer. But maybe you can include it in this thing files. I also saw below in the comments that someone modified the body to fit an m8 connector ... so when the time comes to get my fillament roll of the printer i will definitely switch to reverse bowden ;)

Best regards,

I can't see that these three screws screw into anything? It isn't mentioned in the assembly instructions as far as I can see. They don't grip on to anything for me.

Sorry!!! I forget to insert this image into the assembly guide. i will update immediately.

Can't believe I missed those holes. Oh well, tomorrow is a day well suited to redoing that particular bit.
Posting the complete make in a bit, just need to make sure it works :)

My filament sensor hasn't responded since I used this extruder. Does anyone have a hint what I can do about it?

I have 2 extruders like this working for long time till now and the sensor is working flawless. Did you check the chip sensor if is dirty? or the bearing is run freely without obstacle?

Yes, I always clean the sensor before reinstalling it. The ball bearing also rotates smoothly and without problems.

What for E Steps do you guys have? Are 830 good to go?

Yes if you have a 1.8° stepper motor. Double it if you use 0.9°. After you have calibrate your extrusion multiplier with slic3r and print a 1 perimeter cube to verify.

What fanshroud works with this?

I use the original Prusa R3 version (angled)

Any chance you could make an angled fan bracket fit this fan? https://www.thingiverse.com/thing:3249344
It's been tested and performs a lot better than the stock fan shroud.

MK3 Nozzle RHD Rev. C (Support for Bondtech BMG)

Is the x carriage back supposed to be 2 pieces?

Yes, the X-carriage back is in 2 pieces for easy install the extruder (those parts are the same as Original Bear x carriage back of Gregoire Saunier, the inventor of Bear project)

This looks great. I noticed that RaavHimself has updated his sensor mod to use a round "slider" instead of the original square design and a couple other minor recent changes. Are those already integrated/did you come up with your own solution? Just wanted to confirm before I start printing parts. :)

Yeah, i saw just now. i just based on his idea but the design is mine and it work like a charme. I also have a screw to keep pressure if the magnet is not enough. So don't worry, you can start print!

I'm thinking these two actually reflect changes in 2019 and not 2018?

**** 03/01/18 UPDATE 11: Added stl file of Extruder top without the "Venturi hole"

**** 05/01/18 UPDATE 12: Added a .pdf file of quick assembly photos

haha you are right!!!! i will correct immediately!! Thanks!!!!!

Just trying to keep myself from being confused :) Thanks!

Would be great to have an up-to-date bom of the required non-printed parts. It's a bit confusing to collect them from the description and the comments.

Thanks for your suggestion, i just added the BOM list

Awesome. Thanks!

Think I'm going to give this is a shot on my MK2S, looking promising. The stepper driver for E-axis is partly busted on my RAMBo, any motor will start skipping unless it's a geared feed allowing for reduced strain, hence having to live with a Titan for last year and a half. The problem with Titan - it's clicking very audibly on retractions with the gears properly alligned and it grinds through filament like butter..

Do I actually need the threaded fittings that are used on the lever and to connect 2 halves together on the official Bondtech release or it's held together purely by nuts and bolts? The lever tensioner seems to be screwed into a suare nut, if I'm looking at the STEP files?

Yes, lever is secured with screw and square nut (originally was threaded insert). You have to use only one threaded insert to keep together the extruder bottom to X-carriage

Zero of them would have been nicer though, but I see the space is kinda limited to put a nut (any kind - embedded, slotting in) in there so the fitting is justified.

Hello Marco! It look very intresting. Where can I find info about the shaft assembly? Did you print the shaft gear?

shaft gear and all parts inside bought directly from Bondtech.se I don't yet write a guide how to install, anyway you can see this image took from a facebook group from Olof Ogland : https://www.facebook.com/photo.php?fbid=2252788171408270&set=pcb.914129495594450&type=3&theater

Have you tested whether or not the venturi slot increases airflow? On Prusa's R3 it makes it worse.

Yeah i saw in facebook group somebody post the bad result with hole opened. Probably i will close it.

I see you've closed it now :)
This design differs in how the filament sensor works. Do you think the nailpolish-trick for using non-black filament will still work? Considering printing it in white PETG.

the system i used for indirect filament sensor is working with whatever kind of filament and color (even trasparent)

I'm very new to Fusion 360, but I wanted to create a version of the extruder bottom to use a PC4-M8*1 quick fitting (https://www.ebay.com/itm/10pcs-PC4-M8-1-Pneumatic-tube-Quick-insert-connector/273229852047). I didn't like how much the Bondtech insert one moved around (and it started to get lose). I modified the Alpha 6 Fusion file you had up before. In editing, I increased the diameter of the surrounding material so it would not crack, added threads and raised the floor slightly so it is 5mm from top to bottom to reduce the PTFE's room to move around.

I also changed the hole for the tensioner nut back to a heat insert because using the nut limited the amount of tension towards the high side.

I did also edit the two holes for the lever shaft from 3mm to 3.05mm, just to try to allow for printer tolerance.

Design still works amazing, thanks again for creating this. Please feel free to use this file however you see fit.

Ciao marco, I'm trying to adapt your design to my printer that does not have the sensor for the filament, I would have a question, where I have to insert the shaft 3x32mm? can a screw be used instead of a shaft?

The shaft 3x32 is used to keep the lever, for sure you can use a screw without the head.

@MarcoZ76 is there a reason for that one cut out in the Lever? it makes it weaker on one side

for better insert the pin, mine is not weak at all! anyway i copied from original

the problem is, we are printing in best case with 15% carbon filament, BMG is resin and with higher strength, for FDM print I would do it w/o the cut out.

Just finished printing an Alpha 4 version, looks great and the heat set thread inserts worked nicely. What size fitting is meant to screw into the top for the bowden? The hole seems to measure 8mm. I have standard PC4 fittings that are 6mm and 10mm, but nothing that's 8mm.

For anyone looking for the threaded inserts, these were the closest I could find in dimension to the ones BondTech is selling:

Thanks. Ordered a few from https://www.partsbuilt.com since I’m in the US.

UPDATE: I just realized it was on the screenshot of the list of parts you posted. Sorry about that. I missed it completely.

So, I've done something else, as Panayiotis_3d already mentioned, the hotend is too high up. I have now moved it down 1.6mm. The STLs and the step files can be found here. :)

I hope I could help something

Thanks for some ideas, check in your step files you have the hotend e3dv6 in wrong dimension: see the pics attached

Thx for this, ive moved only the hotend a little bit up, dont saw this, thanks for that :)

the only thing I need to assembly this now is the m3x45 or m3x50 screws

no, really thanks to you!! step by step i'm sure we can develop finally something can work good! I'm waiting for M3x50 and M3x45 too!!

Ive messaged you yesterday on FB too :)

Fixed position (rotation) of the hex for the fanduct mount too.

I hope you like it.

Ive fixed some things:

Lever got bigger hole for the 3mm pin.

X Carriage got bigger pinhole too, the recess for the screw head has been set a little further in. So you can use a normal M3 screw to fix the filament sensor. Got the hole depth 5mm further in. Now you could theoretically use M3x45 instead of M3x50. Whereby M3x50 would be the better choice

Extruder Top got a hexnut for the Fan Support. Bigger 3mm pinhole.

Extruder Bottom bigger Filamentpath, bigger 3mm pinhole, the Filamentsensor hole has become smaller (2.75mm). Now you can cut a thread with a M3 screw and the filament sensor is secured.

These are my fixed STL

All holes holding the 3mm pin are too small for the Bondtech handle. The filament path is now better, but still a bit too small.

The filament sensor cannot be screwed on. How?

My printer is now disassembled. I printed the parts for the second time. I will now wait a bit until the whole thing works. The idea is really great, but a few things still have to be changed. :)

Bondtech uses SLS method to print their extruder. So the designs are optimized for this much more accurate method. This is the reason that all holes seems too tight when we print using the FDM method.

Yeah I understand, but I think that Marco made this design from scratch, or? Yeia sou file mou :)

No exactly, as i mentioned in my other BMG extruder thing (https://www.thingiverse.com/thing:3235716) it is based on stl that i have found here (https://www.thingiverse.com/thing:3182969) and he mention that was the original files from Bondtech but i have some dubt.... Anyway now we can only to make the design better and better thanks to you and all people can give me some idea and have found issues.

Bondtech BMG MarcoZ76 Edition
Btech Bondtech BMG Extruder
by lee0101

That is not the real BondTech BMG body. There are some things inside the models missing.

i already correct all missing things

I saw that, I just wanted to confirm your doubts that he did not get them from BondTech, which he did not.

Could you explain me better this?:<All holes holding the 3mm pin are too small for the Bondtech handle> my english is not good... sorry...
I’m able to screw the filament sensor in my tests. I understand there are many issue in this project, but i have been pushed from some people to upload the project for the step file. Thanks to all feedbacks we can develop a better extruder. We are a community and i like to share some my ideas. Hope somebody better than me can improve it.

Pls add this, so as it is now, Iam not able to install the Fan Support. Please add the hex. That would be the easiest solution.

The change to add space for the collet clip of the e3d v6 is awesome!

Although I think that the E3D should be moved 1.6 mm downwards to match the bear extruder's position. As it is now, it leaves very little room between the hot end and the plastic parts. I doubt that a silicon sock would fit there. And as it is now, it also leaves an opening at the bottom to let the air escape toward the hotend.

Yes you are right, i try to redesign it. Thanks for the feedback again!

Marco, Ive printed the latest parts now in ASA. My BMG will arrive in the next few hours so I will tell you tonight whats going on. The Filamentpath is now great! :) Good Job

Are you going to prepare any assembly instructions? An exploded image of the parts and the screws would be fine.

I cannot see how the extruder is mounted to the X-carriage. There is only one screw, the one behind the heatsink, that connects the two parts. There are 3 holes on the carriage, shaped to hold hex nuts or the thread insert, but there is no way to add a screw to reach them unless I disassemble the stepper and put extra-extra long screws (80mm).

Hi! yes i plan to do an assembly instructiion as soon as the extruder are fixed on all prospectives ( still in heavy alpha stage). Thanks for your feedback about connecting the x-carriage to extruder: i update the design now and you have to use n°3 M3x50 and n°1 M3x30 to stitch all 3 part together.

Just curious, why is the PINDA holder split into two parts?

It’s a remixed from the Bear extrude, for me is more easy to fix in position the Pinda havind 2 part

Issue 2:
I think you forgot to put a hexagonal in the left hole. You can also see that a single "dot" holding the belt will immediately break off.

No, i didn't forget a hexagonal in the left hole, in here i used a thread insert M3 because there isn't enough room space for hexagonal nut. I know there are 2 single "dot" but i can not do without... the belt can sit there without problem

Ok, thank you :)

First Issue Ive found. The Filamenthole is too small. Cant get it in there.

Because it's a printed part the hole can be too tight but with file or a 2mm drill bit you can smooth the path. Maybe i can increase a little bit the hole diameter. Anyway thanks for your feedback

my feedback shouldn't be criticism. On the contrary, I am also interested in supporting you a little bit. 4 eyes see better than 2 :)

Of course all feedback are very welcome!! i just increase the hole diameter, and adjust the path for the bearing and refined the X-carriage to fit better the molex connector for the filament sensor. All files will be ready in few minutes. Thanks again

Thanks for that, so I have to reprint this :D

If you have time, wait a little more, i will add a space also for the collet clip of e3dv6.

How long I have to wait? :D

Probably i will upload the new files tomorrow afternoon

I will wait for this, pls post a comment if youre ready :D

ok i upload new version, try it and let me know.

Iam on my Way Marco, thank you :)

Is this a Remix of the latest 0.6 Alpha Bear Extruder? If yes, sir, you are my hero :)

Yes, it's based on latest 0.6 Alpha Bear Extruder, Not yet tested, still printing and i will post the result very soon!

Good Work Marco, i will print this right now :)

do I need the BMG with the tension screw on the right or left?

This is a fusion remix so you don't need the BMG case, you need only the internal part, see the image attached

Where is the shaft required?

You see, last week i received all the necessary parts from Bondtech except the shaft, since I decided to design my own extruder (based on bear). You were faster! I'll give it a try for sure!

VERY NICE! :) Thaaaaaaaaaank yo

What's a "n°2" thread insert. Could you provide a link or search term (e.g. for ali)?
That's all the non-printed parts needed?

Sounds great. Did anyone test this yet?

Not yet, i’m printing in these days, will post the result very soon!

Comments deleted.

Very nice remix. Thanks for sharing!