Geeetech

Not sure if this is even possible anymore with a single nozzle, as I'm having such difficulty, but the real reason I bought this printer was to print with PVA support. The PVA needs 190 degrees, but my PLA seems to work best at around 210 for a strong bond. I tried both at 190 degrees (to stop it from stopping to keep heating/cooling the nozzle each layer) and Even with a stupidly large prime tower (about 60mm) the filaments don't seem to be separated enough when laying down on my model, as when I put in warm water, the PLA layer lines separate easily, and the PVA doesn't even dissolve after 12 hours!
I put some of the PVA on it's own in water in it disappeared within a couple hours so there's nothing wrong with that.
My retractions between filament changes might be in question as I've no clue what it's supposed to be thanks to there being zero documentation anywhere in the known universe, so I guessed at 18mm. It strings like crazy between filament changes also.
Am I flogging a dead horse trying to get this to work on a single nozzle dual extruder because of cross contamination? I need strength in my finished parts.

Hello.


You have noticed yourself that you are using materials with very different moulding temperatures.

In addition, even deep retraction will not empty the head when changing material.

Therefore, two separate printheads, rather than a mixer head, are best suited for this application.

Coming back to printing with different materials I can recommend you to test some options in slicer. See image:
. .
This will help you to solve the problem of retraction. In my example, the options are default.
By the way, it is very interesting what you are doing.

Thanks for your reply. I am disappointed to hear this, but guess I should have done more research into dual extrusion with PVA before buying this printer. I guess that's why the M stands for mix, and they didn't use a D for dual, since it's like a mixer tap on a bath.
I might try using a really large prime tower with support interface layers, but maybe I'll be wasting my time?

Can I convert the hot end to a dual nozzle?

It's not as bad as you would expect.

Note that you gain invaluable experience and share it with everyone.
I believe that with a little bit of self-denial you will achieve your goal on this printer model as well. It is important that you set the mixing ratio to 0/100 or 100/0%. Perhaps when you go deeper into the slicer configuration you will find an option that will allow you to influence the hot end temperature during printing.

But two separate heads will allow you to experiment on extremely diverse materials.

You are asking if it is possible to adapt your printer to this type of head.
I expect that yes.
Start your search by finding the firmware that performs this function. If you find the right version you will be able to modify the printer.

Well I did find out how to adjust temperatures for each extruder change but the GCode stops to heat up/cool down the nozzle right at the end of an external wall, causing ooz to pile up right where I don't want it. Why it doesn't choose the prime tower to do this is beyond me.

Anyway, changing to a dual nozzle... That might be a bit beyond me.
I think I can get a dual nozzle hot end installed mechanically, but the wiring for another hot end would be a brain tickler and then changing the firmware would really take me out of my comfort zone. I would not know how to even look for this firmware. I'm okay with the Cura settings as you can choose the nozzle offset for each extruder.
I've looked at buying a separate printer that does this, but don't have the room.

You know what, I think I may have a simple solution....
If I replace the hot end with a dual nozzle hot end, and put a buck converter on one hot end to down he voltage and get a 10-20 degree difference, then bam! Problem solved without any software. All I need worry about is upgrading the power supply and setting the nozzle offset in Cura.
Am I missing anything? Seems almost too easy.

I think you forgot the fact that your printer maybe monitoring the temperature and will try to compensate

Did you achive to use pva as support material? i am interested too

PattyPur wrote: ↑

Wed Apr 03, 2019 9:15 pm

I think you forgot the fact that your printer maybe monitoring the temperature and will try to compensate

That might be okay though. It only knows about one nozzle and is only monitoring that one so you should be able to do what you like with the other one technically. The problem is going to be the safety of it. If the converter blows or the board is running too much current to compensate for 2 hotends. or if the other one overheats somehow.
You could switch around the heated bed for the second nozzle. That has to push out a lot more current to head such a large area so it should be able to handle a simple nozzle without adjusting your PSU. But you would obviously be losing out on the heated bed and you'll also have to be doing the coding which you don't want to.

The good thing about the Geeetech software is its open-source so if you screw it up you can just download a clean firmware and start from scratch. You could then maybe have a second board control the bed independently.

It's a lot of effort but the alternative is paying like £1000 which is wayyy too expensive

I got a Geeetech i3 18 months ago, upgraded to dual extruders, and it has its flaws, but it does print PLA and PVA simultaneously.

But now I'm in the market for a new printer, an upgrade, and 2 in 1 extruders like on the A10M and A20M seem to be the only options available, but this post has made me rethink.

I'd love to spend up to $500, more if necessary to get a truly amazing printer which can still let me use PVA for supports, but I don't think it exists.

So... if you are still in the market, I'd recommend one of the Geeetech i3's, as thats what I'm sticking with. If you can deal with the reduced build area, and the slightly older tech within, it is upgradable to silly standards, including true dual extruders