My multi input, multi material, mixing hot end

[T3P3Tony]

@deckingman is the design really too compact to use e3d heatbreaks to save you quite a bit of effort?

[dc42]

Nice write-up!

I think E3D heat breaks would save you a lot of effort, if you can find a way to get round the problem that both ends are threaded. Maybe you can screw an aluminium sleeve onto the bottom thread. It could be worth asking E3D whether they can make you some heat breaks with one of the threads left off, since they may be interested in your research. The top end could screw directly into an aluminium block with a water cooling hole running through it, so no need for a water tank on the hot end at all.

There are also other types of threaded heat breaks that can be screwed into both the heater block and the heatsink without needing to rotate either. For example, this one https://www.amazon.com/Bowden-Extruder-Throat-Heatbreak-3-00mm/dp/B07G99G5MB.

Regarding the filament inlet spacing, what's the reason for putting the BMGs on the outside and the extruder stepper motors on the inside, instead of the reverse? Is it because you sometimes need to dismantle the BMGs to deal with filament issues?

[T3P3Tony]

@deckingman to add to what @dc42 has said e3d have single end threaded heatsinks for use on the Chimera etc: see "whats in the box" here:
https://e3d-online.com/chimera

[deckingman]

@dc42 said in My multi input, multi material, mixing hot end:

Regarding the filament inlet spacing, what's the reason for putting the BMGs on the outside and the extruder stepper motors on the inside, instead of the reverse? Is it because you sometimes need to dismantle the BMGs to deal with filament issues?

Mostly that but also fitting them in the first place. The screws go through the extruder body into the motor so if two extruders face each other, it's impossible. Having said that, maybe I could fix each set of 3 onto a plate, then somehow slot or bolt that plate into place. If I needed to dis-assemble one extruder, I'd have to remove the plate with all three but that wouldn't be the end of the world. It's only a partial solution to the problem though - there would still be a significant offset in X if not so much in Y, but if the inputs to the hot end were angled, it might work. I do have a bit of a concern about heat with those 6 motors being in such close proximity to each other, so having the motors on the outside would be advantageous in that respect.

Ref heat breaks, certainly "off the shelf" ones will save me a lot of heartache. As well as the E3D variant, I was very taken by what the inventor (if that's the word) of the Zatsit printer was doing. Also the Slice engineering Mosquito seemed to be a very efficient heat break design. If I could adapt my design to use either of those, and if either of those companies would supply me just the heat breaks, that's another option.

Lots to think about............

[Martin1454]

Im really looking foward to see how it turns out - The "maze mixing" design sounds interresting!

[deckingman]

@martin1454 There are a few untested ideas that ultimately might not work. I've set the bar quite high trying to do multi-material as well as mixing so in the end, I might have to make some sort of compromise. But for now, I'll leave the bar where it is and keep on trying.

[fma]

Did anyone aready try to inject ink in the melted zone to color the filament? It should be easier to mix CMYB inks rather than PLA...

[deckingman]

@fma said in My multi input, multi material, mixing hot end:

Did anyone aready try to inject ink in the melted zone to color the filament? It should be easier to mix CMYB inks rather than PLA...

Kind of. IIRC, that was something that Adrian Bowyer or one of his students was looking into. If you look at the firmware, you'll see this https://duet3d.dozuki.com/Wiki/Gcode#Section_M578_Fire_inkjet_bits. It seems to have died a death so maybe there were some problems that couldbn't be overcome.

[wilriker]

@deckingman said in My multi input, multi material, mixing hot end:

Ref heat breaks [...] Also the Slice engineering Mosquito seemed to be a very efficient heat break design. If I could adapt my design to use either of those, and if either of those companies would supply me just the heat breaks, that's another option.

At least Slice Engineering sells the heatbreak as spare parts: https://www.sliceengineering.com/shop/heat-break

[deckingman]

@wilriker said in My multi input, multi material, mixing hot end:

@deckingman said in My multi input, multi material, mixing hot end:

Ref heat breaks [...] Also the Slice engineering Mosquito seemed to be a very efficient heat break design. If I could adapt my design to use either of those, and if either of those companies would supply me just the heat breaks, that's another option.

At least Slice Engineering sells the heatbreak as spare parts: https://www.sliceengineering.com/shop/heat-break

ahh, thanks for that.

Edit- £35 USD a pop and I need 6! That's an expensive experiment.

[wilriker]

@deckingman I never said they where cheap.

EDIT: But for test you could start with one.

[deckingman]

@wilriker said in My multi input, multi material, mixing hot end:

@deckingman I never said they where cheap.

EDIT: But for test you could start with one.

True. Or I could try making something similar. Looks like a copper heat sink, copper nut with (probably) Titanium tube swaged in between. hmmmm........

[Phaedrux]

@deckingman said in My multi input, multi material, mixing hot end:

@fma said in My multi input, multi material, mixing hot end:

Did anyone aready try to inject ink in the melted zone to color the filament? It should be easier to mix CMYB inks rather than PLA...

Kind of. IIRC, that was something that Adrian Bowyer or one of his students was looking into. If you look at the firmware, you'll see this https://duet3d.dozuki.com/Wiki/Gcode#Section_M578_Fire_inkjet_bits. It seems to have died a death so maybe there were some problems that couldbn't be overcome.

I think DiVinci sells a proprietary printer that uses inkjet coloring.

[fma]

Mu suggestion was to inject the ink in the melted chamber, not on the printed part.

But It may be difficult to maintain pressure, and it may mess up the print process...

[deckingman]

@fma I don't know what the boiling point of printer ink is, but I'll bet it would likely just vaporise if you tried to inject it into the melt chamber at circa 200 deg C.

[Phaedrux]

You'd think some of the pigment or dye might survive. What do they use to color the filament itself?

[deckingman]

@phaedrux said in My multi input, multi material, mixing hot end:

You'd think some of the pigment or dye might survive. What do they use to color the filament itself?

I believe coloured pellets go into the mix but I'm not sure.

[fma]

@deckingman said in My multi input, multi material, mixing hot end:

I believe coloured pellets go into the mix but I'm not sure.

Yes, you're right. So, it would need to add solid pigments in the mixing chamber. Even more complicated!

BTW, Ian, where you able to test you mixing-matrix-chamber? Does it work?

[inztigator]

Love your blog entries. Looking forward to the follow-up

[JRDM]

I realize you've already bought them (sunk cost and all) but for future reference:

I have a reservoir pump just like yours. That reservoir has a shallow working range. It's about 1cm from full to sucking air due to a whirlpool funnel effect. I end up topping off my loop every 6-8 weeks just from coolant evaporating through the tubing.

You likely don't need the large radiator, a single 120mm cell is fine even for six heat breaks. I use a 80mm radiator for a dual and I've tested both running at 300˚C. The amount of heat lost through a heat break is probably a low single digit watts each.