Color mixing ideas

General hangout discussion area for other non-printing stuff
User avatar
626Pilot
ULTIMATE 3D JEDDI
Posts: 1719
Joined: Tue May 14, 2013 12:52 pm

Color mixing ideas

Postby 626Pilot » Sat Aug 20, 2016 5:53 am

Since some people recently patented a method for dye injection coloring, making it inaccessible to Open Source for the next twenty years (thanks a lot), it's necessary to come up with some other ideas. Three occur to me.

The first option would be to design a machine like the Palette. However, rather than splicing multiple distinct filament colors, we add more melt chambers (the current Palette has only one). The device would support five input colors (white, cyan, magenta, yellow, and black). In that way, it would work the same as taking a CMYK or RGB value to Home Depot and saying, "Make me this color of paint." They start with either black or white paint, and then they add small amounts of the other colors to get the desired result. The machine keeps all five input colors in a melted state, in something like a hot end. The steppers push cold filament through the melt zones, which all converge on a central 1.75mm bore, which has some kind of mixing apparatus, which could be a rotating paddle, or passive fins on the inside that introduce enough turbulence to efficiently mix the colors. This could be implemented on an external device, such as the Palette, or it could be integrated into the printer itself, although that would make it rather top-heavy.

The second option would be a modification of the pellet feed system in SeeMeCNC's Part Daddy delta, which is freaking huge, and which has a hopper that's filled with plastic pellets rather than using spools. It melts the plastic right at the hot end. As above, this would be outfitted with five hoppers (WCMYK) and it would mix the pellets in the correct proportions. Obviously, this would be for super huge printers like the Part Daddy.

The biggest difficulty I see is in allowing rapid color changes. To print something like a photograph would require extremely fine control of the mixing. That would mean a very small mixing chamber. I don't know how short you could realistically have an individual color segment without bleeding. In fact, the current Palette machines assume you'll be drawing a purge wall. If we use converging melt chambers, it might be possible to distribute a number of tiny ports into the main chamber. Rather than having five inputs, there might be 10 to 30 (some multiple of five), all evenly spaced, so no one area of the main melt chamber would be overly biased towards one color. This could prove very difficult to manufacture as a single piece - it would probably require a selective laser sintering machine, printing with titanium powder. Another possibility would be to have each color's melt chamber fork off into several very thin copper tubes wrapped with ni-chrome wire to keep the plastic molten, and these would connect to multiple tiny ports in the main melt chamber.

The third possibility is to adapt inkjet technology. The dye injection method doesn't do this, so AFAIK, those patents wouldn't apply. There's already a project that lets you drive inkjet print heads with an Arduino. The idea would be to put down a layer with FDM, and then return and print the colors on the edges of that layer. This seems to me like it could be a bit messy and error-prone, and I don't know whether it's already covered by a patent. If no one has patented it yet, let this post be the thing that stops them from doing it. 8-) Obviously, an inkjet setup would be bulky, and might be better for printers with a fixed toolhead and moving platform, e.g. polar printers, and deltas with a moving print surface.

Apple has already patented a technology that would go over the print after it's already done, and paint it using some kind of contour-following mechanism.

User avatar
Renha
Printmaster!
Posts: 282
Joined: Fri Apr 11, 2014 2:18 am
Location: Balashikha, Russian Federation
Contact:

Re: Color mixing ideas

Postby Renha » Mon Aug 22, 2016 6:16 am

Isn't your first idea same as one in Diamond hotend, just with mixing device and more colors?
3D printing is magic!

Sorry my engrish :-/ you could PM me in Russian.

User avatar
Jimustanguitar
ULTIMATE 3D JEDDI
Posts: 2631
Joined: Sun Mar 31, 2013 1:35 am
Location: Notre Dame area
Contact:

Re: Color mixing ideas

Postby Jimustanguitar » Mon Aug 22, 2016 8:03 am

Renha wrote:Isn't your first idea same as one in Diamond hotend, just with mixing device and more colors?


I think the idea is more akin to having a diamond hotend with a 1.75mm nozzle creating the filament instead of printing it... The idea, as I read it, is to make a single filament that's color that's mixed before the hotend. The Palette referred to above splices different colored filaments together, end to end. This idea would mix those colors into all of the in between shades.

Qdeathstar
Printmaster!
Posts: 622
Joined: Wed Apr 13, 2016 7:42 pm

Re: Color mixing ideas

Postby Qdeathstar » Mon Aug 22, 2016 5:58 pm

Why does it matter where the color mixing happens? (No experience in color mixing here)


Also, why can't the chimera do color mixing, and do you manually edit the gcode to mix the color or is there some kinda photoshop-esque tool you can use?

User avatar
Jimustanguitar
ULTIMATE 3D JEDDI
Posts: 2631
Joined: Sun Mar 31, 2013 1:35 am
Location: Notre Dame area
Contact:

Re: Color mixing ideas

Postby Jimustanguitar » Mon Aug 22, 2016 8:53 pm

You're right that it doesn't really matter where the mixing happens, as long as it's in sync with your feed and gets delivered when you intend for it to. Diamond and Rova3D do it at the nozzle, (the ORD Solutions bot even agitates the melted plastic as it extrudes!) and the Palette does its splices upstream of the whole printer. The advantage of the upstream solution is that you don't have to have multiple heater and feed circuits built into your printer and can be reasonably universal. There are very few control boards capable of driving enough motors and heaters for XYZ motion as well as heat, temp feedback, and motor control for 5 steppers (6 with the dissolving support option on the Rova3D).

The Cyclops will do color mixing, that's its main selling point. Only 2 materials, though.

User avatar
626Pilot
ULTIMATE 3D JEDDI
Posts: 1719
Joined: Tue May 14, 2013 12:52 pm

Re: Color mixing ideas

Postby 626Pilot » Mon Aug 22, 2016 10:16 pm

Jimustanguitar wrote:You're right that it doesn't really matter where the mixing happens, as long as it's in sync with your feed and gets delivered when you intend for it to. Diamond and Rova3D do it at the nozzle, (the ORD Solutions bot even agitates the melted plastic as it extrudes!)

Do you have a link to that? I found their 5-extruder, but it's 5-in, 5-out.

Jimustanguitar wrote:The advantage of the upstream solution is that you don't have to have multiple heater and feed circuits built into your printer and can be reasonably universal.

This. If you have the printer do all the mixing, you have to significantly modify the firmware, and you also have to add a bunch of heavy stuff (and wiring) to the printer. It would be possible to do this with a Duet if it had the expansion board. RepRapFirmware (which runs the Duet) would have to be heavily modified as well. The Palette goes completely around all of these problems. A script analyzes G-code to find all tool changes, and it turns these into instructions that tell the Palette when to splice what filament. The printer has no idea any of this is going on - it just keeps extruding, as though it was still pulling filament from a single spool. That means it can work with any FDM printer that hasn't been crippled with proprietary software.

User avatar
Nylocke
ULTIMATE 3D JEDDI
Posts: 1421
Joined: Sun Jun 23, 2013 1:43 pm
Location: Iowa

Re: Color mixing ideas

Postby Nylocke » Mon Aug 22, 2016 10:42 pm

I thought there were some issues with hitting the mark on the palette (i.e. at the end of long prints the colors start to shift because of stacking tolerances)? Was your plan with mixing to do "every" color as long as it is solid (no precise gradients or patterns in extrusion) and use purge walls to adjust for the slop like the palette does? Otherwise you kinda need to have more precise control over things, which puts all of this at the nozzle?

User avatar
626Pilot
ULTIMATE 3D JEDDI
Posts: 1719
Joined: Tue May 14, 2013 12:52 pm

Re: Color mixing ideas

Postby 626Pilot » Mon Aug 22, 2016 11:06 pm

The Palette does have some drift. As I recall, their goal is to get the drift good enough that you can print 100 meters without it impacting the model. There is a purge wall involved, so you can get a LITTLE drift without messing things up - the problem happens when the drift exceeds the ability of the purge wall to compensate. The mechanisms they use to account for this are interesting, and you can read up on them on the Palette kickstarter's updates section if you're curious.

My ideas are intended for color mixing, in which you feed different filaments at different rates to get many hundreds or thousands of combinations. Today, 3D printing is like PC graphics in the early '80s, when people had either monochrome or CGA adapters. I'd like to see the technology proceed at least into VGA land, where you could have 256 colors at once.

The other piece of the puzzle is the toolchain. Right now, multi-color prints are done by making separate STLs, one per color. For example, this is how you do 16-color printing with a Diamond hot end. That's okay for some things, and is a step above the 2- and 4-color extrusion people are doing with E3D hot ends. However, it still requires one STL for every color combination; and without black or white filament, the number of available colors is significantly reduced. You can't have white or black, or colors that are anywhere close to them. The best system would allow mixing of five colors (WCMYK) and have at least one other extruder, for support/flex/woodfill/metalfill/conductive/etc. material.

There needs to be a system for exporting color information that's based on treating the surface of the geometry as a bitmap of some kind, and then turning that into color mixing ratios for the extruders. It's pretty easy to do the first half of that (export the color information of the skin of an object), and this has been used in 3D games since the '90s at the very latest. You can do that very thing right now in Blender, a free 3D modeler, and plenty of other modelers have the same capability. You can export the color information as a bitmap, and then you can export the curvature of the object as a UV map, which contains information on the surface normals.

Software that turns that into extruder speed ratios is a different matter. My feeling is that as hot ends that can mix 5 colors show up, people will initially use them to do STL-per-color prints; and eventually someone will write a processor that will take a 2D mesh skin bitmap, combine it with the STL it wraps around (or maybe just the UV map), and turn that into the extruder speed ratios necessary to generate full color output.

User avatar
Jimustanguitar
ULTIMATE 3D JEDDI
Posts: 2631
Joined: Sun Mar 31, 2013 1:35 am
Location: Notre Dame area
Contact:

Re: Color mixing ideas

Postby Jimustanguitar » Tue Aug 23, 2016 12:24 am

626Pilot wrote:
Jimustanguitar wrote:You're right that it doesn't really matter where the mixing happens, as long as it's in sync with your feed and gets delivered when you intend for it to. Diamond and Rova3D do it at the nozzle, (the ORD Solutions bot even agitates the melted plastic as it extrudes!)

Do you have a link to that? I found their 5-extruder, but it's 5-in, 5-out.


http://www.ordsolutions.com/rova4d-full ... ckstarter/
It's 5 in 1 out. The stepper motor on the top of the effector spins and mixes the melted colors as it prints. The Diamond would cause a gradient as you printed around a perimeter because each color tended to be heavier on the side that it printed from.

I caught a couple pictures of it at the Detroit Maker Faire. I believe that their campaign is still up for another day or so.
https://www.facebook.com/themakerhive/p ... permPage=1
https://www.facebook.com/themakerhive/p ... permPage=1

User avatar
626Pilot
ULTIMATE 3D JEDDI
Posts: 1719
Joined: Tue May 14, 2013 12:52 pm

Re: Color mixing ideas

Postby 626Pilot » Tue Aug 23, 2016 2:28 am

Very interesting! Do you know what electronics they're using?

User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1157
Joined: Thu Dec 04, 2014 6:06 pm

Re: Color mixing ideas

Postby KAS » Tue Aug 23, 2016 7:17 am

I've had the Palette for about 4 months now. I'll post more information in a different topic if anyone wants to see the inner working guts.

For the most parts its been unusable on the larger bowden style deltas due to the length of the filament chain. I've not been able to complete a successful print as of yet.
It's actually being sent back to Mosaic this week for a few upgrades that should fix those issues. I will say the communication has been outstanding. We've had one-on-one direct communication with the designer and coders since day one.

User avatar
Jimustanguitar
ULTIMATE 3D JEDDI
Posts: 2631
Joined: Sun Mar 31, 2013 1:35 am
Location: Notre Dame area
Contact:

Re: Color mixing ideas

Postby Jimustanguitar » Tue Aug 23, 2016 8:03 am

626Pilot wrote:Very interesting! Do you know what electronics they're using?

Their own controller. I asked some questions via PM and got some nice answers back from Jenn Gibson who's on the ORD team. Hopefully she doesn't mind me sharing this info.
So right now we have our upgrade reward for our customers who have one of our 5 extruder 3D Printers. In this reward you get:

Full Color Hot End, the color mixer, liquid cooling block, the heater, temperature sensor, 5 new upgraded extruders with generic cartridges, pack of 10 new style nozzles, automatic bed leveling sensor, print layer cooling fan and manifold, wireless controller, tablet, 5 spools of filament CMYKW and the set of 5 Multi Material filaments (so 10 spools in total) and shipping is included within Canada and the Continental USA.

In the FAQ we have the question: Can I buy the upgrade kit and use it on any printer?

The answer is:
Yes and No. Because you need to have a printer that has 8 stepper driver controls (one for XYZ and 5 for the colors CMYKW) and you also need to have a place to put the extruders. One of the main advancements we have made to enable 5 color mixing is the miniaturization of the hotend (it is about an inch and half in diamter) and that is accomplished by the liquid cooling, without it the head would be several inches in diameter which would take all of the space in your printer and you wouldn't have any XY motion in your printer. The RoVa3D and the MH3000 has all of these things.

User avatar
Nylocke
ULTIMATE 3D JEDDI
Posts: 1421
Joined: Sun Jun 23, 2013 1:43 pm
Location: Iowa

Re: Color mixing ideas

Postby Nylocke » Tue Aug 23, 2016 8:49 am

The "wireless controller" is just a Pi2. If you check out the accessories in the store its in there for like $150. I'm pretty sure the tablet is a generic android tablet. Thats what I got from reading around on the website. I couldn't find what they're using for a controller, but if its not custom its probably an Azteeg X3 Pro or something new I haven't seen yet.

Qdeathstar
Printmaster!
Posts: 622
Joined: Wed Apr 13, 2016 7:42 pm

Re: Color mixing ideas

Postby Qdeathstar » Tue Aug 23, 2016 9:27 pm

pallete costs the same as a Rostock v2.. I think I'll break out the spray paint...

User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1157
Joined: Thu Dec 04, 2014 6:06 pm

Re: Color mixing ideas

Postby KAS » Wed Aug 24, 2016 7:39 am

Qdeathstar wrote:pallete costs the same as a Rostock v2.. I think I'll break out the spray paint...


Yea, it's not exactly cheap. I picked it up as a super early backer for $460. Hopefully the firmware changes and the aluminium upgrades make it usable for our Deltas.
I haven't had much time this summer to mess around with it, but anything over 50ish layers starts to have issues with the error correcting pings/pongs not being detected.

On a side note, I'm interested in the new Prometheus hotend getting ready to hit kickstarter. I've been using the v2 for a while now and love it.

dc42
Printmaster!
Posts: 414
Joined: Mon Mar 07, 2016 10:17 am

Re: Color mixing ideas

Postby dc42 » Fri Aug 26, 2016 2:58 am

There are machines doing many colour printing using a Diamond hot end and Duet electronics. See this claimed 300 colour print http://forums.reprap.org/read.php?166,647072 for an example. The main issue seems to be that the Diamond doesn't mix the filaments very well. If we could sort that out, then I think we would be most of the way there. Perhaps a mixing chamber that swirls the incoming molten filaments together would help.

Another issue is that the STL format that we use to describe models doesn't include colours. There are replacement formats that do such as 3DMF.

User avatar
626Pilot
ULTIMATE 3D JEDDI
Posts: 1719
Joined: Tue May 14, 2013 12:52 pm

Re: Color mixing ideas

Postby 626Pilot » Sat Aug 27, 2016 4:21 am

Another method for doing this might be to create a hot end (like the many-ported one I describe above) with an extremely short mixing zone. You could achieve relatively short single-color segments by having the head go somewhere inside the model to purge a little filament, pop out to the outer periphery to draw the desired color, and then pop back into the periphery to start mixing the next color. If there isn't enough room inside the object - say you're printing an image onto a completely flat surface, so there's no "inside" to go into - the printer could instead rely on a purge wall.

It's also possible that the hot end could have some sort of valve that shunts purge plastic into a secondary nozzle that feeds into a Bowden tube that's routed back up and away from the print surface. It would basically be creating "waste filament" from the purged plastic, and this could be recycled or used to print novelty "tie dye" stuff. That would be much faster, and less prone to stringing, than using a purge wall. If you were printing something with a huge number of color changes, like a photograph or painting, the speed gain could be huge.

dc42
Printmaster!
Posts: 414
Joined: Mon Mar 07, 2016 10:17 am

Re: Color mixing ideas

Postby dc42 » Sun Aug 28, 2016 4:16 pm

626Pilot wrote: If you have the printer do all the mixing, you have to significantly modify the firmware, and you also have to add a bunch of heavy stuff (and wiring) to the printer. It would be possible to do this with a Duet if it had the expansion board. RepRapFirmware (which runs the Duet) would have to be heavily modified as well.


What sort of modifications to RepRapFirmware do you think would be necessary? Perhaps anticipating colour mixing changes so that the new mix appears at the tip of the nozzle at the right time - or something else? I am very willing to improve RepRapFirmware to advance the state of 3D printing, as I have done in the past.

User avatar
626Pilot
ULTIMATE 3D JEDDI
Posts: 1719
Joined: Tue May 14, 2013 12:52 pm

Re: Color mixing ideas

Postby 626Pilot » Sun Aug 28, 2016 10:01 pm

dc42 wrote:What sort of modifications to RepRapFirmware do you think would be necessary? Perhaps anticipating colour mixing changes so that the new mix appears at the tip of the nozzle at the right time - or something else? I am very willing to improve RepRapFirmware to advance the state of 3D printing, as I have done in the past.

Probably the best thing to do would be to look at how Repetier does it, and do the same thing, so there aren't different "dialects" for people to deal with: http://www.reprap.org/wiki/Repetier_Color_Mixing

Polygonhell
ULTIMATE 3D JEDDI
Posts: 2430
Joined: Mon Mar 26, 2012 1:44 pm
Location: Redmond WA

Re: Color mixing ideas

Postby Polygonhell » Mon Aug 29, 2016 12:24 pm

dc42 wrote:There are machines doing many colour printing using a Diamond hot end and Duet electronics. See this claimed 300 colour print http://forums.reprap.org/read.php?166,647072 for an example. The main issue seems to be that the Diamond doesn't mix the filaments very well. If we could sort that out, then I think we would be most of the way there. Perhaps a mixing chamber that swirls the incoming molten filaments together would help.

Another issue is that the STL format that we use to describe models doesn't include colours. There are replacement formats that do such as 3DMF.


I think it was Adrian Bowyer that did some work with a mixing hotend probably 3 or 4 years ago.
The last version I remember I think had a motor driving a mixer inside the meltzone (I don't know if it ever actually existed), apparently getting filament to mix evenly is a a hard problem.

dc42
Printmaster!
Posts: 414
Joined: Mon Mar 07, 2016 10:17 am

Re: Color mixing ideas

Postby dc42 » Wed Aug 31, 2016 4:57 pm

626Pilot wrote:
dc42 wrote:What sort of modifications to RepRapFirmware do you think would be necessary? Perhaps anticipating colour mixing changes so that the new mix appears at the tip of the nozzle at the right time - or something else? I am very willing to improve RepRapFirmware to advance the state of 3D printing, as I have done in the past.

Probably the best thing to do would be to look at how Repetier does it, and do the same thing, so there aren't different "dialects" for people to deal with: http://www.reprap.org/wiki/Repetier_Color_Mixing

I guess you don't realise that RepRapFirmware already supports mixing extruders - in fact color mixing in RRF pre-dates color mixing in Repetier by several months. So it's Repetier who introduced a second dialect, not us.

User avatar
626Pilot
ULTIMATE 3D JEDDI
Posts: 1719
Joined: Tue May 14, 2013 12:52 pm

Re: Color mixing ideas

Postby 626Pilot » Wed Aug 31, 2016 11:23 pm

dc42 wrote:I guess you don't realise that RepRapFirmware already supports mixing extruders - in fact color mixing in RRF pre-dates color mixing in Repetier by several months. So it's Repetier who introduced a second dialect, not us.

Then, I hope they implemented it the same way you did. The last thing we need is multiple implementations of the same thing, especially when this technology is so early in its development. I would hate to see multiple toolchains springing up, one per controller. It would be an unnecessary duplication of effort, and it would fragment the technology needlessly.

User avatar
barry99705
Printmaster!
Posts: 703
Joined: Sun Aug 11, 2013 6:10 pm
Location: west ohio

Re: Color mixing ideas

Postby barry99705 » Thu Sep 01, 2016 7:54 am

626Pilot wrote:
dc42 wrote:I guess you don't realise that RepRapFirmware already supports mixing extruders - in fact color mixing in RRF pre-dates color mixing in Repetier by several months. So it's Repetier who introduced a second dialect, not us.

Then, I hope they implemented it the same way you did. The last thing we need is multiple implementations of the same thing, especially when this technology is so early in its development. I would hate to see multiple toolchains springing up, one per controller. It would be an unnecessary duplication of effort, and it would fragment the technology needlessly.

https://xkcd.com/927/
Never do anything you don't want to have to explain to the paramedics.

dc42
Printmaster!
Posts: 414
Joined: Mon Mar 07, 2016 10:17 am

Re: Color mixing ideas

Postby dc42 » Thu Sep 01, 2016 5:38 pm

626Pilot wrote:
dc42 wrote:I guess you don't realise that RepRapFirmware already supports mixing extruders - in fact color mixing in RRF pre-dates color mixing in Repetier by several months. So it's Repetier who introduced a second dialect, not us.

Then, I hope they implemented it the same way you did. The last thing we need is multiple implementations of the same thing, especially when this technology is so early in its development. I would hate to see multiple toolchains springing up, one per controller. It would be an unnecessary duplication of effort, and it would fragment the technology needlessly.

They didn't implement it the same way. Btw it was Adrian Bowyer who designed and wrote the RRF implementation, not me.

Returning to the original topic, has anyone any ideas on how to achieve better mixing of the molten filaments in a design similar to the Diamond? Might ultrasonic agitation help?

User avatar
KAS
ULTIMATE 3D JEDDI
Posts: 1157
Joined: Thu Dec 04, 2014 6:06 pm

Re: Color mixing ideas

Postby KAS » Thu Sep 01, 2016 8:32 pm

.


Return to “The Lounge”

Who is online

Users browsing this forum: No registered users and 1 guest