Help with what dual hot end to buy?

PR1OR

Hi there,

So I’m getting really frustrated with attempting to remove supports, especially on complex prints. I’ve read online there is dissolvable support filament now which I think would be great. I’m using an ender 3 so ideally i think I would want a 2 to 1 hot end (please correct me if this is a silly idea).

Has anyone use this functionality for the purpose I have set above and if so is it worth it over the hours of support structure removal time?

Thanks!

jay_s_uk

Two to one hotends have to be used with the same filament.
If you want to use PVA etc then you'll need two separate hotends (chimera) or two independent tools.
Or look at something like smuff of the mmu2

jens55

I am going to stir the pot here and say that two to one hot ends can also be used by different filament materials as long as they have similar heat ranges.
Having said that, I use a Chimera setup which, while being able to use two different materials, has a bunch of other issues.

Stirring a bit more, I would say that neither of these two solutions are as good as what the uninitiated would think.
I am thinking/hoping that a tool changing hot end might be the answer but that concept is still in it's infancy.

So, to sum it up, short of those things that have completely enclosed support where disolvable support is required, you will likely trade one frustration for another frustration.

To add a bit more - a lot of times the support can be removed easily when everything is printed in the same material if everything is tuned right and the right options are chosen in the slicer. It's a tricky balance but I have had prints where support is very easy to remove. For me it's a combination of knowledge and luck to hit just the right combination. I am sure there are many people out there that do not depend on luck to hit the magic point where everything just works.

engikeneer

@PR1OR I felt your pain and upgraded my corexy from a V6 to a chimera a few months back. My main issue was getting a poor surface finish where I pulled off the support (it was all saggy and horrible) unless I set the contact distance too close so that I struggled to get it off, so thought soluble supports would be the way to go
If I'm honest, I bought the soluble support material (PVA) to use with PLA but haven't yet got it out of the box... Having said that, I have had a bit of a play with two colour printing and so far done a couple of passable quality globes.

Things I've had issues/struggled with:

oozing from the unused nozzle - I haven't quite nailed down the settings to prevent this but it is getting better. Mixture of retraction, an ooze shield and setting lower standby temperatures (though this adds quite a bit to print times...)
setting the nozzle heights - I found with two 0.4 nozzles that came with the kit that I could just assemble it and they were at the same height, brilliant! However, I've since played around with different nozzles (e.g. a 0.3 on the left and a 0.5 on the right). I found with this I had to be a bit more careful as they are slightly different heights, so had to spend a bit of time manually adjusting them.
related to this, I have found that sometimes the unused nozzle can catch the first layer and pull off parts when moving over them (particularly the perimeters on small holes before any infill has gone down). Getting the nozzle heights right has helped this, as well as working on my first layer consistency (I had some issues with my Z probe and I wasn't getting great bed adhesion). This is now less of an issue, but something I never had to worry about with a single nozzle setup.
I used to run a bowden but could never get pressure advance etc dialed in (this was an issue before the chimera) so gave up and went direct drive. The main issue this has given me is space on my x-axis. Luckily I managed to fit it all in without sacrificing too much prointable area, but I've had to use pancake motors so don't have quite the grunt I used to.

Basically what @jens55 said - you will end up causing yourself some other headaches for the privelage. IMO it was definitely worth it, but I quite enjoy fiddling about with my printers...

A few thoughts on the other alternatives:

2-into-1 mixing hotends (like the cyclops) aren't really suitable for soluble support printing. To get them to work properly you really need to keep the unused extruder pushing a small amount else you end up with the plastic sitting in the melt chamber for ages then doing weird things when you next use it. Deckingman has done a bunch of stuff on this if you want some fun reading!
2-into-1 feed systems (like the Prusa MMU v1) seem promising if yu want cheap/low tech. Basically using a Y-splitter on the bowden tube. DisTech sell a system like this (https://www.distechautomation.com/collections/products/products/prometheus-system-e3d-v6-upgrade) and you can find many versions on theingiverse. These would work for what you want but can have issue with clogging if you are not careful. I plan on doing something similar to my old i3 clone one day, if only for the fun of trying
other crazy feed systems (like the prusa MMU2) seem to get around some of the clogging issues (and mean you don't need loads of bowden tubes), but again add complexity. Might be a fun project to put together if you're keen
toolchangers seem the way people are going to get around this, but they put the price of your machine through the roof, and will also give you a bunch of extra headaches. I may one day try and build one of my own, but I can't really justify the cost at the moment.

Hope some of my ramblings help

oliof

Check out enderidex.com -- a pricey solution compared to ender 3 base price, but you get everything for an idex conversion. The person behind this is very approachable if you want a kit without a board.