Bondtech BMG upgrade for the N series

Topics around mechanical design, controller and electronics. Mods & hacks welcome.
Jetguy
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Re: Bondtech BMG upgrade for the N series

Postby Jetguy » Sat Aug 12, 2017 12:16 pm

Sorry, I'm not trying to be unhelpful, I just have a hard time with your conclusion.
reduced the retract from 1.5mm to 1.0mm. This way I could complete the prints. However, this can't be a permanent solution.

#1 I only have been using 1mm retraction for a very long time with Raise 3D printers. Not because of jams but just that some early testing with the Mosaic palette software way back only worked with a limited retract distance. I never needed to change it after that. That was true for BMG and the mini since I have multiple printers with both solutions. I find no such correlation to a BMG specific issue.

#2 Longer retraction of like 6-10mm OK, could understand jams, 1-2mm shouldn't be causing jams and indicates a hotend issue, not a feeder specific issue.

I think you ran into a coincidence here that you changed the feeder and just happened to have an issue at the same time.
1.5mm should not be causing jams, not in my experience and moving to 1mm fixing it, I would not consider that BMG specific or an indication at all. I would consider that maybe you had some dirt or fiber or burned filament check ball effect in the cone of the nozzle and the only way to remove that is cold pull filament cleanouts, changing the nozzle, or sometimes the classic burnout (high temp method with the nozzle removed).

socke
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Re: Bondtech BMG upgrade for the N series

Postby socke » Sat Aug 12, 2017 1:05 pm

Jetguy wrote:Sorry, I'm not trying to be unhelpful, I just have a hard time with your conclusion.

No need to sorry. But I didn't state this as conclusion, I just tried to say what I've observed. I'm also aware, that there may be no causality between the jams and the BMG.
However, thanks for your input! I consider to swap the nozzle and/or hotend later. And also thanks for sharing your settings, this is helpful to know!

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jmp
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Re: Bondtech BMG upgrade for the N series

Postby jmp » Sat Aug 12, 2017 8:52 pm

socke wrote:Maybe I have to change the retract speed, too? It is set to 30 mm/s, currently.


If it were me I would see if 20mm/s is better.
RL Name: Jason Preuss Thingiverse: JMP Youtube:http://youtube.com/c/patterntoprint Website: http://www.patterntoprint.com

socke
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Re: Bondtech BMG upgrade for the N series

Postby socke » Sun Aug 13, 2017 5:51 am

Yes, in the meantime I found that 20mm/s seems to work better.

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JohnSays
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Re: Bondtech BMG upgrade for the N series

Postby JohnSays » Tue Aug 15, 2017 2:23 pm

Look back at my posts on the same subject. I solved it. I found that the motors were getting way too hot with the cover closed during ABS printing. I have not had a clog since I simply started venting the air temperature down below 55C.
- John
2 Raise3D N2 Duals, V2 nozzles, Bondtech BMGs, and adjustable table

socke
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Re: Bondtech BMG upgrade for the N series

Postby socke » Wed Aug 16, 2017 6:19 am

No this isn't the same issue I think. Motor was not even handwarm, cover was always left open and I was printing eSun PLA+.
Meanwhile I think the issue is more related to my print object and hotend or object cooling. My object needed a really large number of retracts with only very short tracks of extrusion between. Other, 'normal' objects coming out nicely. But I need to do some more tests.
I already swapped the hotend, also used brand new nozzles, so I can exclude that this is an issue of one specific nozzle or hotend.
Btw: Even if I had a bumpy start with the BMG, so far I really like it!

Jetguy
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Re: Bondtech BMG upgrade for the N series

Postby Jetguy » Wed Aug 16, 2017 12:07 pm

Just a note and I asked for Bondtech to say this, I have found 2 of the recently purchased BMG style extruders (a single lefthand flip and the dual Raise 3D specific version we are discussing) had the actual mini style hobbed gear slightly loose on the jackshaft. In other words the tiny setscrew was loose. It takes a really good non-worn hex key because that screw is so short you there is no depth of the hex key to bite in.
What I saw was, the gear can rock on the shaft (the shaft has a flat for the setscrew to better mate with). Eventually, a loose setscrew will rock back and forth and damage the shaft. Not to mention, the entire time, you have backlash and lost distance.

Just saying, check your gear. Bondtech stated they are using thread locker to prevent this and should be factory tight but again I found 2 of my own personal brand new units had this setscrew is loose so again, please check. Better to check and find it tight than to not check and assume it is good.
Last edited by Jetguy on Wed Aug 16, 2017 12:37 pm, edited 1 time in total.

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JohnSays
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Re: Bondtech BMG upgrade for the N series

Postby JohnSays » Wed Aug 16, 2017 12:11 pm

Yes, I found it loose on one of my 4 shafts too.
- John
2 Raise3D N2 Duals, V2 nozzles, Bondtech BMGs, and adjustable table

Jetguy
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Re: Bondtech BMG upgrade for the N series

Postby Jetguy » Wed Aug 16, 2017 12:55 pm

The setscrew in question is the same as shown- it's just not on the motor shaft in the BMG but the geared shaft. https://drive.google.com/file/d/0B7A1ME ... NfNms/view
Drivegear setscrew.jpg

As seen in the BMG Dual extruder. I had to use a tiny flat tip screw driver to rotate the shaft until the setscrew was visible.
Drivegear setscrew2.jpg

In fact, on this early unit i had been using up until I recently bought that "never installed" BMG dual from another user and found that both drive gears had loose set screws and I had been printing with this until a short time ago.
Video shot just minutes ago.
https://youtu.be/CDC8qogG0QY

Again, be sure to check both sides of the unit for dual extruders.

firesped
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Re: Bondtech BMG upgrade for the N series

Postby firesped » Thu Aug 17, 2017 6:04 am

I want to make sure this is noted. remove the first link of the cable chain to reduce the stress on the cable for the extruder board.

On a side note, I have to replace my left hotend, I'm pretty sure at this point the thing actually melted down but it is all wrapped up in insulation still. I removed some filament today and some of it got stuck in the coldend. so I had to remove the hotend to clear it. I'm getting inconsistent extrusion from the hotend.
RL name: Michael Nolen
printers:
raise3D N2 kickstarter Early Bird
Trinus Deluxe (running smoothieware on Azteeg X5 GT board)
Monoprice Maker Select v2

socke
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Re: Bondtech BMG upgrade for the N series

Postby socke » Thu Aug 17, 2017 1:06 pm

OK, I finally solved my issue:
My jams came from a too strong object cooling, so it seems sometimes the filament already hardened in the nozzle. It happened by loading a wrong factory file.
However, the BMG runs like a clockwork now . :-)

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JohnSays
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Re: Bondtech BMG upgrade for the N series

Postby JohnSays » Fri Aug 18, 2017 12:06 pm

As a hope factor for anyone still having a struggle with the new BMG: I have been very successfully printing ABS with HIPS support, eSun ABS+, and some Polymaker PLA+ on two N2s. I keep them printing as close to 24/7 as I can. Once I got the support extruder calibrated into Simplify3D, these extruders have printed better than even the earlier Bondtec extruders did. I think nothing of loading up a print with dissolvable support now. My biggest problem is keeping enough filament at the ready -- it seems to come and go from market. As a note on that: I contacted eSun directly and found that it is possible to order 3 Kg rolls directly from them. It comes out to about $13/Kg with shipping, but that's with a quantity of 40 3Kg rolls -- way too much for my burgeoning business(g).
- John
2 Raise3D N2 Duals, V2 nozzles, Bondtech BMGs, and adjustable table


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