Reviews3D Printer Hardware

All-Metal BMG Direct Drive Extruder – My New Favorite

Browsing on AliExpress, this new All-Metal BMG extruder caught my eye. So I ordered one and here’s my thoughts for it.

The Good

  • All-Metal construction makes it great for Direct Drive applications.
  • High Quality finish made from aluminium acts like a heatsink.
  • It’s really compact compared to the regular BMG extruders.
  • The machining on the filament is really good.
  • It includes a good PTFE bowden tube. It’s not Capricorn, but it’s better than average with 1.9 mm internal diameter.
  • The thermistor and cartridge have quick connect plugs making the servicing easier.

The Bad

  • The bowden coupler at the top can’t be replaced for now. If it fails, you need to be creative to do a fix.

The Ugly

  • It’s a bit hard to use it with a Volcano heat block because the wiring can he a bit hard to route. Using a normal heat block should work better.
  • It comes with a plastic gear. I understand that this is to avoid friction and increase service life, but I would use a metal one. I will update this section after a few hundred hours of printing with additional feedback.
  • The motor does not have a D cut.
  • 3D printed mount when used in a remote bowden setup.
  • It adds a bit of weight to the whole assembly, but I think it’s worth it.
Volcano tight fit

I also ordered a Plated Copper Volcano Heat Block . This thing is gorgeous. The finish is really nice and I’d say it’s well worth the price. The only bad thing is the added weight. It’s a lot heavier than an aluminum block, but when used with high flow rates and large nozzle size, it’s well worth it.

Considering everything, I think this extruder it’s worth the money asked for it, but before buying it you should know the future setup. It’s great for direct drive, but it’s the same as any regular BMG extruder when used as a remote bowden extruder.
I will update this post with more information over time, after i install it on my printer.

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Boz
Boz
4 months ago

FYI the reason the gear is plastic is so that the whole thing doesn’t self destruct if there is a clog. It is intended to be a point of failure. If the gear were metal, the extruder might tear itself apart if it can’t push filament through, and at the least it will distribute wear on all the gears evenly (so you will have to replace all the gears for wear and tear)

Mariano
Mariano
10 months ago

I have a similar set-up:
https://www.reddit.com/r/3Dprinting/comments/jlfau7/poor_mans_hemera_mostly_made_with_aliexpress/

I initially had the same version that you have with the holes in the bottom, but I had issues with it.
The problem it has is that it has a threaded hole for the heat break. I had a jam inside the extruder, and when I tried to remove the hotend the break neck broke. It was a “titanium alloy” break. Long story short, I was unable to remove the broken part from inside the extruder.

As a replacement, I bougth one of these:
https://es.aliexpress.com/item/4000511065747.html?spm=a2g0o.productlist.0.0.fd5c1ed4qGjA2E&algo_pvid=34d6ae0f-f625-4cfb-b196-a06b818813d5&algo_expid=34d6ae0f-f625-4cfb-b196-a06b818813d5-11&btsid=2100bb4a16041395770361256ee248&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

This model has a smooth (not threaded) hole for the heat break, so I used a smooth bi-metal break like this one:
https://es.aliexpress.com/item/4000698566141.html?spm=a2g0s.9042311.0.0.2f2963c0aS2xKE

The extruder has two small screws inside that hold the break on place. This also allows you to put a piece of teflon tube inside to get a couple more millimeters of separation between the extruder and the volcano heat block. It would be good to have a turned teflon piece for that.

As the new extruder lacks the two small screw holes in the bottom to hold the mount in place, I designed a new version that has a piece that goes between the motor and the extruder, and holds everything in place.

I have to upload my 3D printed pieces to Thingiverse, but I’ll do it when I finish giving it the last touches.

Home-Fried 3D Printing
Home-Fried 3D Printing
1 year ago

Thanks for the detailed review! Do you know the spacing of the two screw holes on the bottom of the extruder (next to the heat throat hole)? It looks like a lot of the newer versions of this part are missing those and I was thinking about tapping my own holes.