A different multi-extrusion approach - UM tool / printhead changer

[SandervG 1,521]

How do you usually dissolve your PVA? Have you tried using more water pressure, vibrations or other ways to influence the water, besides just putting it in a bucket?

[foehnsturm 969]

Just the old-fashioned style. Lots of warm water and a brush.

As far as I know, an ultrasonic cleaning bath works best.

Hopefully UM owns one

[foehnsturm 969]

BTW, currently doing another run with different settings. Now it looks like I'm on the right path. A big nozzle and thicker layers for PVA seem to do the trick.

0.1 mm layer and 0.4 nozzle for PLA & 0.2 mm layer and 0.8 nozzle for PVA almost works like charm. Way faster and consistent PVA depositing, less tool changes, less overall printing time.

[SandervG 1,521]

Picture or it didn't happen

[foehnsturm 969]

It's still happening

[sambianchibazzi 9]

Look what I found in the printer this morning.

However, I'm not sure if I'll ever manage to totally dissolve the PVA ...

But slicer generated support just doesn't work reliable with complex geometries where lots of tiny PVA support structures would start on top of PLA surfaces.

If it'll ever see the light of day it should look like this.

 

Hi,

Can you send me the STL so we can do a test print ourselves? Thanks!

[foehnsturm 969]

It's on Grabcad https://grabcad.com/library/epicyclic-bevel-gear-reducer-1

[neotko 1,417]

Just a bit offtopic, but not much.

I just saw this full BCN3D calibration video, and I must say it's perfectly planed. The firmware, for dual, should look much like this and allow adjustments on the firmware without the need of adjusting x/y/z manually (except on the case of using a hotend with actually 2 extruders on the same place).

It's a quite brilliant and simple process of calibration

 

[foehnsturm 969]

Hi @neotko,

Well I'd say we're already on par at least

[neotko 1,417]

 

!

[foehnsturm 969]

I'll tell you on June 29 at the latest.

[ultiarjan 1,223]

It's a quite brilliant and simple process

 

that is indeed a pretty well thought out proces!

[foehnsturm 969]

Ok, now I'm satisfied

[ultiarjan 1,223]

Ok, now I'm satisfied

 

About what? I can't see anything

[mastory 44]

maybe an ultrasonic bath?

[Allanlin333 0]

I wonder if you could do some sort of mechanism at the top instead of the side, so it wouldn't take that much printing space. You are doing a great job!!!

New idea for new version of ultimaker: auto print change/ changing printheads in the middle of a print to create duel print materials.

[foehnsturm 969]

After some not so pleasant experience with syringe-based paste extruding recently, I started thinking about a different way to do it. I'm not heading for food printing but more for a way to combine FFF-parts with stuff like silicone. So if anyone already has some experience with paste, please feel free to share.

My main concerns with the standard approach are the following:

 

• Pressure - Syringes, especially with an attached tube produce huge back-pressure with highly viscous material
  
• Power - Therefore a highly geared powerful driving mechanism is required
  
• Control - Highly viscous material under high pressure seems to be very hard to control (think of those silicone cartriges)
  
• Ease of use - Prming /pushing the stuff through a bowden type tube can take ages
  
• Waste - With materials like silicone the entire drive-train is impossible to clean, you'll lierally throw away everything each time
  

 

 

I'd like to have a solution to extrude a reasonable amount of highly viscous material (like 10-20 ml) with a special head for the tool changer. Even though they're way too big you can google "zombie blood bag" to get an idea of what I'm thinking about

Edited July 6, 2016 by Guest

[DidierKlein 729]

I wonder where that idea of playing with syringes came from

[foehnsturm 969]

 

And I'm really grateful that I didn't have to try this at home.

[jhertzberg 19]

The Structur3D folks went the syringe and geared extruder route. They even sell a package with the paste extruder integrated with a UM2+. It should be straightforward to adapt their extruder to your toolhead changer. Unfold ~fab uses compressed air and a moineau pump instead of a geared motor, definitely not something for a home use.

I ran into the same five issues as you when I built a syringe extruder, but since I'm looking to print clay I'm now thinking about skipping the high viscosity issue entirely, and doing some variant of a powder bed type approach.

[bratmody 0]

hi. i think a logical concept and a good innovation if successfully executed by R & D fellows.

i hav a different problem with dual printing. my files for printing are usually more than 150 mb. doing double head printing both cura and repertier have limitatins and the print cannot be done with confidence at least by me. i would like to know if people have got success with files above 200mb. please advise.

[foehnsturm 969]

First try with GreenTec PLA and Polysupport. Temp for GreenTec was way too high for good overhangs (205 °C), I will do another one

[DidierKlein 729]

@foehnsturm in your quest to mix flexible filament with PLA, i don't know if you remember but we talked about a flexible bio compostable filament made in Germany, it's a good one, it's called WillowFlex

I could give it a try with my single setup if you want to see how it reacts to PLA or PLA-PHA?

Polysupport looks like an interesting material for support i was pretty impressed by the quality of what i say at AM amsterdam

[foehnsturm 969]

@DidierKlein, now I remember.

Yeah, it would be great if you can do a first test.

[foehnsturm 969]

Coupling and extra print head for dual extrusion now approaching pre-production state.

Edited July 14, 2016 by Guest