6 in 1 out Hot-End development I started to develop my own hot end based on the E3D hot end. its intended use was to be able to mix white, black, cyan, magenta, yellow. to allow for any color just like a normal printer does, also I added one more input to allow for a support material. the support material should not be mixed with the colors for its primary purpose is to be dissolved, but there is no reason you can't. (it should be noted that any filament can be fed in). (all hot ends are designed around a 0.2mm hole size) so off I went and soon created my first design the V1, it was more or less just a heater block replacement for the E3D hot end. [attachment 94525 1.png] on the inside 6 tubes would converge to meet in the middle and funnel into a nozzle at the end, one of the drawbacks was this meant much more filament had to be used when changing color or mixing it. but it did have the advantage of using standard M6-1 threaded nozzles and the rest of the E3D hot end kit, meaning only more heatsinks and heat brakes would have to be purchased. [attachment 94526 2.png] next came the V2. this model addressed many of the flaws of the V1. [attachment 94527 4.png] the large differences are the shape and the way filaments are mixed, in addition, the V2 was a milled to size, meaning that it was its own nozzle, and no change could be made without making a new one, in terms of switching from a .2 to a .4 meant you would have to break down the hot end and rebuild it to extrude a different size. however, this meant instead of a large mixing area a volume of only 0.16mm^3 would have to be purged to change or mix new colors. the downsides are it was larger and bulkier, with the upside of excellent filament mixing and changing [attachment 94528 5.png] [attachment 94529 6.png] lastly came the V3, a child of the V1 and the V2, while haveing the externals of the V1 it had the internals of the V2, the only downside to this is that the nozzle is milled to size and can't be changed, but the form factor is smaller and takes less time to heat up. [attachment 94530 7.png] again it has a similar build to the E3D hot end [attachment 94531 8.png] a cutaway shows that the V3 has a longer mixing run then the V2 and must clear 0.63mm^3 to change or mix colors. [attachment 94532 9.png] in the future, I plan to make a version that implements the small channels that are good for mixing but allows for nozzle changes and still maintains the small V1 form factor also, the heatsinks do have to be modified on the V1 and V3 hot end to fit in a small cluster, however on the V2 they will fit with little to no modification. in addition, they should be made out of pure aluminum, as it dispels heat the fastest and keeps the filament above melt temp. [attachment 94533 10.png] when it comes to cooling this thing I made a carriage that supports a 60mm fan, due to the large volume of fins on all of the heatsink's, cooling should not be a problem for low to mid-range temp plastics but may need to be modified for high temp plastics. [attachment 94534 11.png] any ideas for thoughts are greatly appreciated, please stay tuned to see further updates please not while this is based on the E3D hot end it is a personal project and will not be sold or mass produced. I am simply looking for ideas for further iterations or hoping my work will spark an idea in someone else. it is in no way meant to infringe on the Intellectual Property agreement E3D has for its products. https://reprap.org/forum/read.php?2,770028,770028#msg-770028 Sat, 10 Oct 2026 00:47:05 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?2,770028,771540#msg-771540 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,771540#msg-771540
Quote
frankvdh
Quote
deckingman
Then there comes the question, what do you need to print that has to be multi colour? [snip] Is it all worth the cost and hassle? I keep asking myself that question and the jury is still out.

Wrong question! The correct question is "Is it fun?"........................
...................

Same answer - the jury is still out. On reflection though, I guess the answer must be yes otherwise why do I stick with it?

Some examples of stuff I print in colour, aside from vases, pot holders and the like. Personalised key fobs, luggage labels and place mats with the person's name in their favourite colour on a black or white background. Project box lids with labels for switches and indicator lights embedded into the part in a different colour ("On", "Off", "Power","Fault" etc....). Also different filaments - i.e. PLA parts with a "window" printed in clear filament such as T glass. E3D edge PETG with E3D scaffold for supports (not the edge needs much support).]]> deckingman Developers Sat, 03 Jun 2017 03:43:11 -0400 https://reprap.org/forum/read.php?2,770028,771359#msg-771359 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,771359#msg-771359 sniper567 Developers Fri, 02 Jun 2017 02:23:51 -0400 https://reprap.org/forum/read.php?2,770028,771338#msg-771338 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,771338#msg-771338
Quote
deckingman
Then there comes the question, what do you need to print that has to be multi colour? [snip] Is it all worth the cost and hassle? I keep asking myself that question and the jury is still out.

Wrong question! The correct question is "Is it fun?"

But yes, I suspect that something like a CYM inkjet injecting into molten filament must surely be cheaper than $480. If someone could just get round to formulating the ink and designing the inkjet and nozzle...]]> frankvdh Developers Thu, 01 Jun 2017 19:01:21 -0400 https://reprap.org/forum/read.php?2,770028,771336#msg-771336 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,771336#msg-771336 I agree it will not be for the standard person right off the bat, but for someone like me who has most of that stuff just lying around the only thing I have to order is the stepper motors. obviously, not everyone has extra stuff, but I would be willing to venture that people who are willing to take the step to full 3d color printing probably have most of the parts already.

also in regards to what I would make

I make a lot of mechanical things as well as decorative objects, but I model a lot of mechanical prototypes, one thing I would love to do is to be able to print a heat map of the load pressure or aerodynamic pressure on a surface of a part that way I could show a client how their part will work, I also do a few architecture bits(in the old days we built things with balsa wood and foam board), and if I could have like 6 spools instead of 50 that would be helpful. as you stated and I agree not for the everyday person but for people who use their 3d printers for work or maybe school would love this.

I will keep a list of all expenditures to see just how much it would cost.]]> sniper567 Developers Thu, 01 Jun 2017 18:55:33 -0400 https://reprap.org/forum/read.php?2,770028,771326#msg-771326 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,771326#msg-771326
Then there comes the question, what do you need to print that has to be multi colour? Although I do have a Diamond hot end, in all honesty 80% of the stuff I print are things like printer parts, enclosures, brackets, kitchen and garden accessories, containers of various descriptions etc etc all in single colour. So I have 3 E3D titan extruders, a carriage that takes up a lot of movement in X and Y and weighs a ton. For sure I can make some pretty neat decorative objects but that's only a small percentage of the stuff that I want to print. Is it all worth the cost and hassle? I keep asking myself that question and the jury is still out.]]> deckingman Developers Thu, 01 Jun 2017 17:37:49 -0400 https://reprap.org/forum/read.php?2,770028,771167#msg-771167 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,771167#msg-771167
I agree that there is no proof of concept yet. but in terms of price.
I use this for a Bowden extruder and I have no problem having the filament traveling an upwards of 6 feet in a tube,
[attachment 94832 IMG_83901.JPG]
right now it's a bit disassembled as I am rebuilding my printer, but I don't see why we can't just string 6+ tougher on the side of the printer. or as I have seen many times, people have a bar that they put there spools on and feed them from there.
in terms of cost, that small 15oz 400 step motor was only $10 on eBay and that 3d part is probably less than a few dollars to print.

while at first, it may be a bit of an investment and time it will definitely pave the way for 3d printing and as it develops further I'm sure the price will go down.]]> sniper567 Developers Wed, 31 May 2017 16:25:14 -0400 https://reprap.org/forum/read.php?2,770028,771050#msg-771050 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,771050#msg-771050
Quote

...it seems like there are very few people willing to go past 3 filaments, there are a few 5, 6,7, filament things that I have seen but the vast majority of them stick three? I wonder if there is a reason?

I'd say reasons are:
number of steppers required,
finding a place for all those extruders and spools, ( Yes! There really IS a printer underneath this chaos ;) )
and missing proove of concept.

Arcus M2 has gained a lot of interest, but his design isn't available yet and I'm still waiting for a "3D printed Mona Lisa " as a showcase of a working full color mixer. Mixing filament for a Vase mode object isn't such a challenge IMHO.]]> o_lampe Developers Wed, 31 May 2017 02:29:22 -0400 https://reprap.org/forum/read.php?2,770028,770977#msg-770977 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770977#msg-770977 [attachment 94813 Shape+factors+The+drag+coefficient+describes+how+easily+fluid+flows+around+a+particular+shape.+Blunt+objects+have+high+drag+coefficients..jpg]
as you can see we have to think about it in the reverse but the idea is the same having one large pipe would create a ring of turbulent plastic with would probably try to leak out the top, but with steps, it should help mitigate this problem. after reading a bit about fluid dynamics it seems like this would be more efficient if it was a cone shape and did not have steps at all but that will require a very special drill bit or some very awkward milling,
also the nozzle is a standard e3d design with the exception of the mixing tunnel and the path before the filaments actually comes together should not dramatically affect anything, only the path where the mixed filament is traveling would create an issue. but to the best of my knowledge any hot end that actually mixes filaments tends to be longer or at least bigger in volume to account for the mixing time.

in regards to rolloo

thanks for the post, but you bring up an interesting thought with your posts it seems like there are very few people willing to go past 3 filaments, there are a few 5, 6,7, filament things that I have seen but the vast majority of them stick three? I wonder if there is a reason?]]> sniper567 Developers Tue, 30 May 2017 12:59:15 -0400 https://reprap.org/forum/read.php?2,770028,770962#msg-770962 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770962#msg-770962 RepRapColourMixingReport.pdf


Quote
rolloo
more like RepRap.me DIAMOND FULLCOLOR HOTEND
now more like....

ebay



Here's another interesting design...

]]> rolloo Developers Tue, 30 May 2017 11:27:10 -0400 https://reprap.org/forum/read.php?2,770028,770931#msg-770931 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770931#msg-770931
Like this, but shorter:

]]> o_lampe Developers Tue, 30 May 2017 07:14:23 -0400 https://reprap.org/forum/read.php?2,770028,770916#msg-770916 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770916#msg-770916
Do you have any reference, theorical or pratical, about this point ?

The thinnest channels seems very long, relative to the diameter of the bore, and the viscosity of the material. Is there a way to estimate the resistance as a function of the flow speed and the viscosity, for such a thin channel ?]]> M_Xeno Developers Tue, 30 May 2017 05:31:17 -0400 https://reprap.org/forum/read.php?2,770028,770849#msg-770849 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770849#msg-770849 [attachment 94774 Untshnaitled.png]
I believe that using lost wax casting I can get a very complex but simple static mixing nozzle, and I can use a mix of polishing agent and water pumped throw the chamber to polish the inside, again I'm still researching fluid dynamics to see how to best implement this.
also right now my printer is in pieces, I'm upgrading its frame so, I can get a bigger print area, but what I would like to do is use gear boxes to turn the 400 steps into something like 4000 by using a 10:1 gearbox, this would mean it moves a lot slower but it whould be far more pricise, and if i put a small gearbox on the exstruder moter and mess with the firmwhere i believe i chould more accuritly inject new filliment reducing the biuld up of pressure that is put on the melted filiment by the unfelted filiment, idealy if i chould move the smae volume of plastic in as comes out.

just some napkin calculations

if we extrude a .4mm extrusion over 10mm

V = pi(.2)^2(x) = 1.2571mm^3 total volume of exstruded fillement

meaning

1.2571 = pi(.875)^2(x)

x = .52264 mm of 1.75mm filament is needed to be pushed in to get exactly 10mm of the filament on the printing bed, this is assuming perfect use and no loss.

I know with the old 200 step motor and a mk7 head you could get filament to move 0.16761mm per step, while that should be fine we have to account for the melting of solid filament to liquid and the build up of presser as the fulfilment is funneled down to the nozzle, with the 400 step, one step moves the filament .0838mm, again we have to account for the presser build up, but it should be far more controllable especially if we put a gear box on it which would reduce the step angle even more.

the issue arises where

.52264/.16761 = 3.11819 at 200 steps, what this means is that even with one step there is a remainder that must be accounted for if we round down to 3 steps we might have under extrusion and only input .50283mm^3 of the filament. and if we round up to 4 step we might get some over extrusion meaning that we would input .67044mm^3. minimizing this leftover step I believe is important to solve the issues before they arise.

again much of this requires fluid dynamics with I am still looking into but in all, the use of a wipe tower a 400setp motor and possibly a gearbox with some special firmware and the right nozzle, I don't think it will be a problem.


also I believe the pellet system is definitely interesting but when it comes down to it, the same thing is happening at the end, molten plastic is coming together and will be mixed in a toothpaste faction, unless the colors are mix together first then extruded after being mixed, but at that point you might as well just get different color filament, not to mention now you have a pot of plastic that must stay liquid and be able to travel.

and in response to deckingman idea about dye, I believe what you described would work but I am more of an electric and mechanical background while I do have a bit of chemical under my belt I would need to know a lot more about plastics and how they're made. the real issue is there are lots of ways to do thing the way we want, we have factories that mix and create all the things we have talked about, but there is no way I can mount a factory to the top of my printer. but it is an interesting idea!:)]]> sniper567 Developers Mon, 29 May 2017 15:43:16 -0400 https://reprap.org/forum/read.php?2,770028,770844#msg-770844 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770844#msg-770844
Maybe another approach might be just to use a single clear, transparent filament then mix dye to the desired colour and add it to the molten filament? So there would be two stages of mixing - one to mix the liquid dye to get the correct colour, then a second stage to mix the dye with the molten filament. If you could somehow coat the inside of a tube with dye, then push the filament through that tube, it would coat the outside of the filament bead so maybe it wouldn't matter is it wasn't mixed all the way through, as long as it was coated all around? Just kind of thinking out loud.............]]> deckingman Developers Mon, 29 May 2017 15:13:32 -0400 https://reprap.org/forum/read.php?2,770028,770812#msg-770812 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770812#msg-770812
If mixing is necessary maybe it makes more sense to look at the pellet extruder Idea. It might be easier to add teh "full color" feature to an pellet extruder than to go the route of 6 Filament Extruder and a mixer.

But I do mostly software so I might be wrong,...]]> JustAnotherOne Developers Mon, 29 May 2017 11:48:37 -0400 https://reprap.org/forum/read.php?2,770028,770800#msg-770800 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770800#msg-770800 PDBeal Developers Mon, 29 May 2017 10:28:46 -0400 https://reprap.org/forum/read.php?2,770028,770740#msg-770740 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770740#msg-770740 Out_off_box thinking: would it be possible to use SLA printed parts to generate a better mixing path? Like curved filament path and spiral mixing chamber...]]> o_lampe Developers Mon, 29 May 2017 01:48:42 -0400 https://reprap.org/forum/read.php?2,770028,770724#msg-770724 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770724#msg-770724 [attachment 94748 V6.png]
first off it still used M4 set screws to close up the holes, this one has six input filaments and uses the cyclops heat brakes with will allow me to make a short water cooling or fin attachment for cooling. also, the design is scalable to accommodate more input but may require a 24v heater.

also, the plug idea was simple to implement and using the same idea as the set pin I can mill a pin that will plug most of the hole when not in use
[attachment 94750 Unanadtitled.png]

lastly, I am still testing the validity of static filament mixing but one idea I have is to take a standard nozzle (this way it's familiar and easy to do) and implement the mixing system inside the nozzle.
[attachment 94749 dfgsn.png]
the one shown above is the stacked disk idea mentioned in a previous post

and in regards to frankvdh idea about fluid dynamics, I agree, the rest of the work is just figgering out how to make everything fit, the most important part is getting the filaments to mix. I have been studying up on fluid dynamics but it's a big subject and I'm just reading textbooks and researching this stuff on my own, someone with prior knowledge would be very useful.]]> sniper567 Developers Sun, 28 May 2017 19:08:19 -0400 https://reprap.org/forum/read.php?2,770028,770710#msg-770710 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770710#msg-770710
Perhaps we need someone with a knowledge of fluid dynamics/hydraulics on how to maximise the turbulence in the flow of the viscous, incompressible filament (Stokes flow)? I guess that minimising friction (to minimise force applied by steppers) would be another, secondary, concern.]]> frankvdh Developers Sun, 28 May 2017 17:28:25 -0400 https://reprap.org/forum/read.php?2,770028,770696#msg-770696 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770696#msg-770696
.Arcus3D M2 - Six material, active mixing linear delta 3d printer

I have been following his work and even attempted to make one of my own, but ran into the problem that he stated, it was difficult to get the tolerances tight enuff where I could reliably not have leaking.

that's why I wanted to make one that did not require an external motor.]]> sniper567 Developers Sun, 28 May 2017 15:47:06 -0400 https://reprap.org/forum/read.php?2,770028,770690#msg-770690 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770690#msg-770690
Quote
frankvdh
Right... so the screw needs to turn at a faster rate than the filament flow rate, with room around the outside of the screw for filament to flow back. Perhaps the ultimate would be a paddle wheel which just rotates the molten filament in the mixing chamber and doesn't push it out at all.

Yes, I do believe that's how the guy who posts on these forums (can't remember his name) is doing it with his active mixing hot end. Something similar to that anyway.]]> deckingman Developers Sun, 28 May 2017 15:18:14 -0400 https://reprap.org/forum/read.php?2,770028,770688#msg-770688 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770688#msg-770688 frankvdh Developers Sun, 28 May 2017 15:12:33 -0400 https://reprap.org/forum/read.php?2,770028,770664#msg-770664 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770664#msg-770664
Quote
PBDeal
...and those Industrial extruder have an internal rotating screw that feeds the plastic out.

That's the point: the screw pushes the plastic out, but to mix the different colors, you would want the screw to pull the filament back into the mixing chamber and partially work against extruder pressure. That way, they mix up much better.

@deckingman
Did you try to use a different mix_ratio tool for infill? That way you could also get rid of the unused filament when printing single color.]]> o_lampe Developers Sun, 28 May 2017 11:04:43 -0400 https://reprap.org/forum/read.php?2,770028,770606#msg-770606 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770606#msg-770606 deckingman Developers Sun, 28 May 2017 04:26:01 -0400 https://reprap.org/forum/read.php?2,770028,770573#msg-770573 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770573#msg-770573
you make a good point. however, the scale that we are working with is much smaller than that of industrial scale. consider this.when you look at the screen that you are reading from right now, all you see is a picture, but if you look using a magnifying glass you will notice that it is just a combination of 3 very separate colors, I agree with you that if you want purple the best way to get it is put in a purple filament, but for the purposes of 3d printing if we can get the "toothpaste look" small enuff it will blend like the pixels on your screen.

also, I've been hand mixing filaments to test deckingman idea about hue with clear vs white filler, I can say I have successfully created gray from black and white and orange from red and yellow. I would say it takes about only a dozen of passes with a screwdriver before the colors start to mix, and considering the quantity of plastic would be even smaller in the nozzle in believe I can get it to the point where it starts to merge like the pixels on your screen. I think this is a problem of size and quantity and should be achievable.

however, it sounds like you have a fair bit of Knowledge about mixing plastics and I would love to hear more!]]> sniper567 Developers Sat, 27 May 2017 22:01:34 -0400 https://reprap.org/forum/read.php?2,770028,770567#msg-770567 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770567#msg-770567
I could be wrong but in my experience with industrial plastic extrusion if your extruding say red and you add one blue pellet to make purple you end up with red and a thin blue stripe before you ever see purple. And those Industrial extruder have an internal rotating screw that feeds the plastic out. All of the ones I've worked with extrude natural color with the odd color pellet mixed in say in a 1000:1 ratio.

I think what your trying is a good idea, but you might want to step back and see if you can even mix plastic colors to make new colors. For what I understand, Ink jet and laser printers do this by layering different colors on top of each other in different quantities to create all the colors, but that's not going to to work very well with a 3D object. It might not be a bad idea to see how that sand caste printing does multi color as that's full color 3D objects.]]> PDBeal Developers Sat, 27 May 2017 20:16:35 -0400 https://reprap.org/forum/read.php?2,770028,770511#msg-770511 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770511#msg-770511
Quote
frankvdh

..............................Plugging a hole that isn't being used is surely a non-issue? Just leave some filament in there.

Actually, IMO it's not a bad idea to have unused inputs plugged. I used to just leave filament in my diamond when only printing a single colour but there are two issues. Firstly you need to retract and un-retract all filaments simultaneously otherwise all that happens is that filament is drawn from an unused input, rather than the nozzle tip and it's like printing with no retraction at all. With Duet electronics, this is accomplished by using firmware retraction. The issue is that the "unused" filament gets ground away by the hobbed bolt constantly retracting and un-retracting the same few millimetres, so eventually, it stops being moved and you end up with effectively no retraction. The other issue is that the filament gets cooked by being kept at a high temperature but not moving. When it comes to using that input again, the first thing you get (at least with PLA) is a load of what looks like steam or vapour followed by a very runny goo until some good stuff comes through. The way I get round it when printing a single filament is to load the main reel into one input but pull off a couple of lengths of few metres and load these into the "unused" inputs. Then, with a tool defined to use all 3 extruders, I set the mixing ratio to 0.98:0.01:0.01 so effectively using 98% of the main reel and 1% of the other two. This ensures that the "unused" inputs are kept moving, albeit very slightly but it's enough to prevent the two issues detailed above.

Ref stepper motor hardware and firmware. Duet (WiFi or Ethernet) will give you 5 plus Duex5 will give you another 5 making 10 in total. Assuming one for Z, and one each X and Y that leaves two for extruders on the Duet main Board. I use the Duex5 but currently only need one of the 5 available to give me three extruders so in theory, I could add another 4 making 7 colours/filaments in total.


Ian]]> deckingman Developers Sat, 27 May 2017 10:44:39 -0400 https://reprap.org/forum/read.php?2,770028,770448#msg-770448 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770448#msg-770448 MechaBits Developers Sat, 27 May 2017 02:28:38 -0400 https://reprap.org/forum/read.php?2,770028,770430#msg-770430 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770430#msg-770430
You make some good points

In regards to you question about the electrics, I have a ramps 1.4 that I am currently using as a test bed, using a CNC shield I was able to get 6 filament extruders with little modifications, I'm looking into if I can chain another board to add 4 more stepper drivers or if there is a larger CNC board I can use.

And the issue with plugging a hole is unless the filament is under pressure I have seen melted plastic push out plugs of filament if they were not being held by a stepper or a clamp.

now this V5 is just a rough draft I wanted to get out of my head before I turn in for then night

NOTE: it is a monstrously large hot end I will work on getting it smaller. just for fun, I designed it with 10 inputs but of corse, it can be reduced down to less.

[attachment 94664 ZBVXV.png]
I designed this one using the Cyclopes heat brakes with the idea that I can design a water cooled jacket or fin assembly to slip over them and thus solve the cooling problem. also, you'll notice it has a sharp 90-degree turn that the plastic has to make but I have used a cyclopes hot end before and found they do work so it should not be a problem but testing will determine if that is true or not. it should be noted that the small prongs you see sticking out the side are M4 set screws that simply fill in the hole.

lastly, you'll notice the nozzle,
[attachment 94665 tshsh.png]
while I did not draw the threading the top piece slips into the bottom and as a single piece is inserted into the hot end, you will notice a small gap between the top and the bottom, I plan to make this a mixing chamber,
the first idea is to use plates with off centered holes, this should push the plastic back and forth to mix it.
the second idea was to have two halves of a cylinder and CNC a sin wave or something and then press them together to create the channel, I will test both idea to see which one works the best or if I need a plan C.

keep those ideas coming!]]> sniper567 Developers Fri, 26 May 2017 20:33:00 -0400 https://reprap.org/forum/read.php?2,770028,770425#msg-770425 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770425#msg-770425
One big heatsink for 6 filaments is going to be awkward to design and fit if the heatbreaks aren't vertical. OTOH, If the heatbreaks are vertical, then it will take less space anyway. Vertical heatbreaks leads to some complexity in the filament path inside the brass heater-block, ideally curved paths from vertical at the heatbreak down to perhaps 45 degrees at the mixing chamber. A sandwich of 2 brass parts clamped together perhaps? The top part has vertical heat break mounts, bottom part has sloping feed paths down to the mixing chamber. You could even have 3 or 4 slices with gradually changing slope angles. This would require some precision manufacturing and assembly though. Soooo... have you investigated fabricating the heater-block by metal 3D printing (e.g. sintered titanium)? I don't know how expensive that would be, but maybe OK for testing prototypes? Another thought... curved brass tubes inside an oil-filled heated chamber?

The assymetric heater cartridge in the V1 design seems to me to be a likely weak point... some of the filament feeds will be hotter than others. I prefer the solution with the heater cartridge in the middle of the block. In any case, you should probably use thermal insulation around the outside of the heater block to help keep the temperature uniform?

To reduce the Diamond "toothpaste-stripe" mixing problem, perhaps use a helical mixing chamber? Or outlet/nozzle? That might be more achievable with a 3D-printed heater-block. But perhaps using a cyclical small retract/extrude drive pattern on all the filaments would improve the mixing?

I agree that 6 colours is probably minimal... CYMK, white, transparent. Mixing in white will make the output more pastel, not more transparent. So design for 7 (or 8?) filaments to allow for supports and other stuff (flexible filament, temperature dependent colour-changing filament, glow-in-the-dark filament).

Plugging a hole that isn't being used is surely a non-issue? Just leave some filament in there.

Probably there's going to have to be a whole new controller/interface board designed too? Arduino won't be fast enough, and I don't think there's anything RAMPS-like that can support 9+ stepper motors. Is there any firmware that supports 9+ steppers?]]> frankvdh Developers Fri, 26 May 2017 19:46:57 -0400 https://reprap.org/forum/read.php?2,770028,770409#msg-770409 Re: 6 in 1 out Hot-End development https://reprap.org/forum/read.php?2,770028,770409#msg-770409
You make a lot of good points, while, in theory, you only need 5 to print full color I have designed the V1 to V4 to accommodate 6 filaments, this means all the colors and a dissolvable filament

Also, it was my understanding that I only need cyan yellow magenta black and white to make a full-color spectrum?

Also, you hit on some points that I had thought off and given me more ideas so thank you, and don't worry anything that you see that can be improved I'd love to hear about it. I'd rather be told I'm wrong then not being told at all, so keep those ideas coming.

Based on what you said I have a few things I'd like to implement in the next design,
1. An actual mixing element that would visible make the filaments mix more homogeneously, I have seen hot end that use a small stepper motor to mix the filaments but I should prefer to have a solid mixer, otherwise, I believe changing the nozzle would become too difficult.
2. A way to plug hole that is not being used ( possibly a spiral screw )
3. Also, I have been looking into making a hot end that would funnel filament straight down at a 90 degree angle and then turn 45 degrees to mix and then be extruded, I'm still researching how this might be machined or made, but I hope to get the overall diameter down so smaller machines can use it
4. While I agree the cost is not so much an issue in the RND stage, I do hope I can get it down, that way it does not deter other people from trying something similar, I personally have chunks of metal lying around and a good shop so it's not difficult to fabricate the things I design, but my hope is that other people are able to make what they want.

Also, your idea of mixing transparent filliment with colored Filaments is interesting, I do believe I should be able to change the saturation by simply adding more white, however, a clear filament does offer an interesting possibility by allowing you to mix clear or semi-opaque colors in addition to the solid white. I will do a test to see is it is possible if it does I will definitely add a slot for a clear filament to the design.

I will post these pictures later

Keep the good ideas coming]]> sniper567 Developers Fri, 26 May 2017 18:19:26 -0400