Ok, Cyclops (and Chimera) Q&A time! I'm seeing quite a lot of questions,

3D Printing
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Ok, Cyclops (and Chimera) Q&A time! I’m seeing quite a lot of questions, a few misconceptions and a whole bunch of cool suggestions and discussion.

First some reference material:

Secondly, lets tag in some relevant characters
@Joshua_Rowley (Who is actually the primary designer of this whole setup)

@Whosa_whatsis @ThantiK @Thomas_Sanladerer @Camerin_hahn @Nils_Hitze @Jelle_Boomstra @Laird_Popkin @Mark_Moissette_ckaos

To be clear from the outset: Cyclops is not a mixing hotend
Yes, two materials are extruded from a single nozzle, and yes both materials can be extruded at the same time. However the primary application here is to print each material in turn one after another, and not so much about combining the two materials. (Nothing stopping you doing so if you want however).

Polymers by their very nature flow in an extremely laminar fashion. This means that if you extrude a black filament and a white filament into a single nozzle then you will receive extrudate that is black on one side and white on the other. You will not get grey. Cyclops does not have any mechanism or facility to take these two discrete streams of molten polymer and agitate them in any way to form a homogeneous mixture.

Although Cyclops is not a mixing hotend, it is a spin-off from a bunch of colour mixing experiments where we found somewhat accidentally that you could switch colours extremely quickly with certain melt zone geometry.

The switching is not done with a “Y” type affair where you pull out one filament back beyond a junction and then push down a second in it’s place. The “Y” approach is fairly neat and simple, but suffers from globs and blobs left in the “Y” areas that can jam things up, as well as requiring large amounts of purging and some colour bleeding from leftover plastic intermittently contaminating the current plastic.

Cyclops does all switching in the molten fluid state and this allows for really really quick switching. I’m hesitant to give out hard numbers here, but essentially the required prime tower size is so small that we have to artificially make it larger because otherwise it would be too thin to adhere well to the bed. Additionally there is extremely little to no colour bleed and you get very pure output. Even with extremely strong colours such as black and white.

We played with a whole bunch of cool little ideas like passive ball bearing shuttle valves, but ultimately found that simpler was better and there was little advantage to being very fancy.

We’re absolutely still working on mixing hotends. However it’s a deceptively complex problem. We have really encouraging prototypes and some cracking performance. I’m pretty optimistic about it, but there are yet still a few unsolved problems.

Any other questions or speculation welcome. I’ll do my best to keep up!

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With the current nozzle setup in the single color hot ends, nozzle switch outs for say, size changes, are very fast. How will this work with the cyclops?

Also, have you done any tests with multi-material, instead of multi-color, for instance HIPS and ABS? I know when we have done tests using Stratasys ABS “model” and their “support” materials in our 2X we had issues with nozzle jams when one nozzle drug through the other material and pulled material in. I think their “Support” is HIPS but they will never give you a straight answer on that. That’s the only support/model material test I have had an opportunity to so I don’t know if standard HIPS acts the same way.

Also with jams what is your advice for clearing them? Now That I’ve seen the drawing for the heater block its pretty obvious there is not going to be a good way to do anything like a cold pull. Have you guys found a good way?

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@Sanjay_Mortimer thanks for the update. I had a good feeling you would be providing our little group a chance for some q&a.

My little question: Can you fully speak to supported firmware(s) yet?

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I’ve got two three things i want to ask about:

  • Does the longer and more complex melt zone increase oozing, lag or introduce other issues? Does it improve performance for thicker layers or faster printing?
  • If yes, will you offer larger nozzles? Something like the BigRepOne could surely use a 2mm one.
  • On the topic of licenses, i believe @Brook_Drumm recently removed the NC part from his CC licensed files. The way i understand it is that copyright does protect the drawing itself, but not the parts made from it, so a NC clause would only get people to go “ugh, it’s not really open source” without keeping other companies from cloning or adapting (which a patent would…). Are you planning on removing the decorative “NC” part from your design files? Any plans on registering a trademark for E3D instead?
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I like the write up. Thanks for your time.

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@Joe_Spanier The nozzles unscrew and can be easily changed just like v6 etc. The nozzles however are smaller and not compatible with v6. At present we are sticking to the one tried-known-good nozzle size for the first run, to make things more consistent. No issues anticipated for other nozzle sizes, but just keeping things conservative and tested for now.

We’ve done multimaterial support with HIPS and ABS, but just not enough testing to really say it works. We’re trying to stick to what we have done extensive testing on rather than speculating. Again, no issues anticipated but I don’t want to make assertions I don’t have tests to back up.

Stratasys support for ABS is certainly PS based (I’m fairly sure it’s not got the butadiene impact modifier that would make it HIPS as opposed to PS, as it’s so brittle and breaks away). However it goes a lot deeper than that, they have some serious chemical/polymer engineering dark art going on that makes their support work unlike anybody else. I’m also really impressed that they got a working support material for PA12 recently, which is seemingly methacrylate based like many of their other support materials. How that adheres etc I have no idea.

You certainly can’t cold pull this hotend. Tactic number one is not to put shit filament into a complex extruder. Having to tolerate the bargain basement filament is seriously an impediment to progress. With that said, cyclops will accept pretty much anything you throw at it as long as it doesn’t have nasty inclusions etc. You can remove/replace the nozzle and I expect that removing it, heating up the block and purging hard would get out most nasties. Messy for sure, but functional.

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@Brandon_Satterfield
Our current workflow is:
Repetier Host to arrange and setup a job > Integrated Cura to slice > Repetier-Firmware on the machine.

There’s no reason you couldn’t use marlin, and no new code would need to be written, you’d just have to tinker with configuration.h.

Repetier stack is just nice in terms of being well integrated.

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No love on the tag? :stuck_out_tongue:

Interesting approach using a fully melted filament feed to flow into the nozzle.

How much does this increase the required pressure to extrude filaments?

Does it use a single heater cartridge or 2?

To further expand on the multi-material question, how well does HIPS handle being kept in the melt zone? Usually it’s not an issue but it’s not that large either.

And add me to the “If it jams, how do you fix it?” question

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@Mike_Kelly_Mike_Make Single heater cartridge.
I’ll let Sanjay handle the rest, but I will say that I wouldn’t expect it to increase necessary force very much. I’ve found the majority of the force needed, especially at higher flowrates, is getting it through the sub-mm nozzle bore. The 90 degree turns shouldn’t offer much resistance because the local velocity is so low.

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@Thomas_Sanladerer
This is a complex one, yes the molten zone is long, however we have to introduce another area in the hotend now other than the classic:
Cold Zone > Transition Zone > Melt Zone > Nozzle.
We now have:
Cold Zone > Transition Zone > Melt Zone > Molten Zone > Nozzle.
The distinction is important because the polymer has to become a fluid before turning the corner. This gets a bit fuzzy because the polymer can turn the corner before it is truly isothermal with the block , but I digress.

Because the channels are longer there is more back pressure for rheological reasons, but because the polymer has a longer residency time in block it is often more fluid and easily moved around. The lord giveth and the lord taketh away… Basically you come out pretty even with regards to your volume of extrudate you are capable of outputting per unit time compared to a normal hotend.

I expected there to be a lot more ooze and retraction to be relatively ineffective, however it seems that it’s actually pretty manageable. Things like wet filament will screw you due to the high residency time etc, but as long as you’re putting decent enough stuff in and have some sensible retraction setting you get nice clean prints. A bit of Z-Hop is helpful here too. A lot of this comes back to the fact that retraction doesn’t really apply negative pressure in the hotend, but actually just serves to relieve the pressure back to zero. If all filament was more tightly toleranced we could do some pretty awesome things, but that’s beyond the scope of this discussion.

I honestly don’t know what to do with the whole NC/CC/Blah blah. They are basically ineffective licenses for hardware. I’m open to suggestions. The NC serves as a sort of gentlemans request which a fair number of reputable companies respect. I’d like to find a better way, and that probably means dropping NC and using something like the CERN OHL.

We have a full international trademark for E3D and associated branding. We do enforce this to stop people passing off fakes which they are calling “E3D HotEnds” which you see a lot on eBay etc. Taking the design and copying it is one thing, and within the bounds of the law, but then using our branding to promote a knockoff is not. People by and large understand that we make high quality stuff, with proper customer support, and assured levels of reliability. I want to ensure that our name doesn’t get muddied and genericised much like “J-Head” is now a generic term. It’s a complex topic, and probably again beyond scope for a post about Cyclops etc.

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Awww @Mike_Kelly_Mike_Make I do apologise!

Pressure questions answered above.

One cartridge.

I don’t have good data beyond knowing the hips goes in and the hips comes out, and anecdotally everything looks fine for the couple of prints we’ve done. The plural of anecdotes is not data however and I just haven’t tested this extensively. We’ve just gotten in a few different bits of awesome test and inspection kit, and hope to have good answers for a lot of things soon.

I honestly don’t have a hard and fast best practice for what to do, as it just hasn’t happened to us. But as mentioned above a spirited purge with the nozzle removed is probably a functional, if messy, way to go about getting crap out. You’d have to have a really really large inclusion to get something to jam hard inside the channels, while they aren’t huge by any means they should still allow pretty much anything I’ve seen go into a hotend pass through.

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Well I’ll sure get you some HIPS data. Love the stuff.

Thinking of flow dynamics, would the “printing” filament push a little ways into the “idler” filament channel, thus preventing cross color contamination during a print? More of a confirmation that my theory is right than an accusation of function.

Also Josh needs to work on his dimensioning on drawings :slight_smile: I’m sure your machinist loves that lol. Though I assume what we get is not what’s sent out, or you probably work digitally with them. I know my model doesn’t need to be 100% accurate, but that’s just how I roll.

The 7.5mm dimension for the filament channel should be on the upper left drawing since right now the 3.3mm is kinda confusing. There’s also no dimensions for the filament channel coming out of the heat break and into the channel. I’m assuming it’s 2mm then reduces down to 1.5mm. It’s also not clear as to how deep the “2mm” hole goes.

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Have you done any testing with multi-material printing using materials with significantly different extrusion temperatures? Looking at the drawings, I’d assume you can’t use materials with significantly different temperature needs (say, PLA and Tritan), but is that something you’ve tried and is my intuition right about what happens?

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@Mike_Kelly_Mike_Make I too theorise that the printing filament enters the idle channel to an extent, especially being that the idle filament is retracted somewhat when set to idle. This certainly seems to be why we can get such clean changes with so little bleed.

I really want to have one printing, and suddenly cool it rapidly with upside-down air-duster and then mill it in half and see what is going on so we don’t have to speculate here. We’re just too low on prototypes etc to be cutting them up just yet.

The drawings were just slapped together this afternoon for the purposes of showing them here etc. @Joshua_Rowley is actually a total pro at drawings when he needs to be, promise!

We have a pretty special relationship with our machinists. It’s not like we just send off drawings and get back parts. We do design for manufacture in extremis. Each part is designed for a specific machine, with a specific set of tools in the changer, all GCODE is lovingly hand crafted. We tightly control every part of manufacture, from the brand of drill bit used to the source for the stock metal from which parts are made. This is a large part of why our stuff works where clones fail. The “drawings” we send to the machinists would be confusing as they’re so heavily annotated etc.

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That’s the way to handle a machine shop. I don’t even have that kind of knowledge and my machinist is in house, granted we’re not dealing with fractions of a mm tolerance.

Just had to give josh a hard time because I was catching a bunch on the last drawing. Though he was hastily doing them for me so it’s hard to complain :slight_smile:

Can’t wait to get my hands on one. Keep up the good work.

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@Stephen_Baird No testing done on highly dissimilar processing temp materials. We’ve done ABS/HIPS but they are pretty damn close in terms of temperature.

I really want to get a direct extrusion setup on top of one of these instead of bowden so we can do flexibles printed in place alongside rigid materials. So many cool design opportunities for multi-material printing.

The nice thing is that if your materials really are that dissimilar etc then you can just swap out the hot side for Chimera parts with very little effort and have two individually controllable nozzles for more conventional printing. Hence the “legends pack” which is both hot sides in a single kit.

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If you have 2 e3d v6’s (or 5’s for that matter) would he cyclops heat breaks work with it. I don’t imagine the .5mm makes a huge difference but I know it can be difficult to thread on flated faces.

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That looks pretty cool, did you consider going all solid state and putting a thermoelectric cooler on the ‘cold’ side?

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Peltiers don’t very much like the types of temperatures we’re dealing with here if you’re talking about moving heat to the heat block. If you’re talking about just moving heat to ambient, peltiers are only going to increase the mass of the device, and the size of the heatsink/fan needed (since they add 2-3x more heat then they move).

There’s no benefit that I’m aware of to dropping the cold side below ambient. Thus, no reason for a peltier in my opinion. A properly designed HSF will get within ~5C of ambient anyway with the minimal heat loads encountered here.

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@Tim_Elmore I think the peltier comment was directed at creating a temperature differential across the block. If this worked, (which I doubt it would, but it would be great if it did), it could help with the dissimilar materials problem, and could also be used to lower the temperature of the inactive side to limit its thermal expansion, though with the active filament capping the idle channel, that’s not nearly as much of a concern as it is with a dual-nozzle setup.

So yeah, not only ineffectual for mixing, but with the negative pressure of retraction pulling a cap of the active material into the idle channel, I see how it would be pretty good at preventing unwanted mixing, even without the shuttle valve. I wonder, however, if you could increase the mixing behavior by switching back and forth between extruders rather than pushing both at once. If you pushed, say, 1mm of filament from one side and then, without retracting, push one millimeter of filament on the other side (I’m not sure what the optimum amount would be, but intuition tells me it would be between .5 and 2mm on each side) without retracting, you would constantly be in a purging state, and the colors may mix more thoroughly than just running both simultaneously.

Then again, the fact that the filaments go through a 90-degree turn before meeting probably helps to sharpen the color transition because the plastics must be fully molten at that point, so an un-melted (or at least significantly more viscous) core of filament can’t push past the molten plastic in the hot zone, which definitely contributes to the long purging times when changing filaments on some hot ends.

Well, I guess I need to get the legends pack…