So for my first self designed printer I wanted to do a dual extruder design. Purpose should mostly be printing in 2 different materials, not only 2 colors.
I now have to decide with which type of dual extrusion I want to go. Since I intend to build a Lulzbot style cartesian printer I have complete freedom in which system to use.
Personally I always really liked the idea of having independent carriages like the BCN3D Sigma has. However, the “Prusa-Style” Y splitter for bowden tubes seems to be picking up speed right now.
I can see having problems with flexibles when using the Y splitter (bowden + flexible is not perfect, adding a splitter may just be too much).
Which type of dual extrusion using multi materials do you guys prefer?
I guess the “oldschool” 2 fixed hotends on 1 carriage can be ruled out by now…
Single Stepper Tilting Dual Extruder. A switching extruder that tilts. The inactive extruder nozzle tilts onto a fine leaf spring which stems the flow of plastic. No ooze, no waste, independent temperatures, fast switching between filaments, light weight, direct drive, extruder heights set in firmware and firmware is already available in Marlin.
They all have strengths and weaknesses. I’m presently implementing a Y splitter, because it’s the easiest path to dual extrusion on my current printer, I don’t care about flexibles, and I don’t have to give up any build area.
@Dale_Dunn Yah I guess if one is fine with using a bowden system and with the small drawbacks that come with such a system it’s perfect. I’m thinking about retrofitting my Kossel Mini with such a Y splitter because it seems to be the best option for deltas. For a cartesian however I would like to have 2 different nozzles so that you can actually have them at different temperatures.
@Peter_Stoneham I like this idea, would be fun playing around with such a system. Would you also tilt the stepper for driving the 2nd filament?
@Nils_Hesse the two filaments in a tilting extruder generally run either side of the hobbed drive. The tilting mechanism switches the driven side and the stepper is reversed.
I actually talked to Josef Prusa at Maker Faire in NYC about flexibles on the Mk2 since I’m planning on purchasing it and he said to simply use Cheetah from Ninjatek which is just barely harder than their Semiflex.
For a personal printer I suggest switching/pivoting like what Peter is mentioning and what stratasys has a patent on. It’s the best way of dealing with dual nozzles. I also really like Ultimakers approach, but that has it’s own challenges.
I’m not sold on the Y split design. the strings from the extruder are a major issue and that can cause jamming in the tube. I know people claim it’s not, but there’s so much variability it makes me concerned.
I’ve had good luck with the cyclops but I would be concerned about using it with PVA because of the temperatures. It also is critical to remember to shut off the heat otherwise you’ll cook the media in the cyclops and kill it.
Independant carriages are very nice, and the best way to prevent oozing in a dual nozzle approach. Plus it gives you a nice dump and prime zone which is invaluable in dual extrusion.
I’ve tried pretty much every way, so I can elaborate if needed.
(FYI, Someone from Ultimaker here)
I tried the Y piece on an UMO years ago. Didn’t like the results at all. The amount of purging you need to do is insane. Just cost time and material. There are also materials you really do not want to mix in a hotend.
It can also jam up quite easy if you turn up the temperature a bit too high due to stringing in your Y piece.
I would go for 2 heads. It is the easiest to get right, you will not have oozing problems. A lifting hotend as in the UM3 requires a lot of things to be a 100% right. Early designs of our lifting mechanisms worn out really quick for example. I wouldn’t lock the hotend in the same place every time.
(Not sure why Prusa is getting all this praise at the moment. Guess his marketing improved?)