Dual Extrusion Fail

[dennisjm]

Well I gave it a good honest attempt this evening to get dual extrusion working in 2.2.

Here is why it doesn't work for me. I'd love to get some suggestions for how I could make it work if it's working for others and not me.

1) I originally tried the object as is, support material in one extruder, plastic in the other.
* fail. After deprime/prime at tool change there isn't the right amount of plastic in the nozzle and it skips or blobs. You should be able to tune the retract right correct? You'd think so but when it sits for indefinite amounts of time depending on the amount of support material there isn't really a correct setting.
2) I added a skirt with layers 9999 and perimeters 3 for on the main extruder.
* fail, the nozzle always started at the same spot and eventually a buildup of plastic on the skirt caused the skirt to knock loose from the print bed.
3) I added an alternate object instead.
* fail, the order of objects can't be set so what would happen is it would print the layer on one object and switch tools and print the other then switch again so I got no benefit of using a dummy object as the priming object.

Anyway... in summary.. We're almost there guys.. Keep up the great work. Now just add the purge walls like everyone asked for months ago

[dennisjm]

I should add, aside from the nozzle purging issue, I'm actually having quite good luck with the new 2.2 features. There are some very very good improvements.

* ability to select which extruder does the raft. This is crucial because I can now do the raft out of the same material that is doing the supports. Before when I tried to print this way I couldn't get the support material to stick because the raft was the other plastic.
* variable support density for top layers. This is extremely nice for saving support material but still getting a nice print. Before if I printed with enough support material to get a nice print I had to dissolve for much much longer.
* And of course the fact that I can remove supports from where the model doesn't need it or add more as necessary.

Anyway, almost there.

[dennisjm]

If anybody has a way, with any object except using a skirt, to make the first layer of real plastic print the other object.. the one used for priming instead of the one on my real object first, that'd be great. That's really all I'm unable to solve right now. The result is I get a nice first layer of the dummy object but I'm still missing a layer of plastic almost on the real object. (The real object has a quite small first layer... hence the dissolvable support print.)

I've tried importing the objects in different orders but that doesn't make much difference.

Another thing that would be nice is when I did use a skirt, it prints on the outside of the raft. It would be nice to somehow make it print on the raft for better adhesion. Thin wall features just don't stick to print beds that well. Works for 1 or two or even 5 layers but eventually the skirt wants to break free (especially if you have purging issues.)

[dennisjm]

Ok I was able to keep playing with this and finally get a better result.

If you use two processes and set the first process to print the dummy object then the layer will print in the correct order so that the nozzle is primed right for the real object.

This works only because the 2nd material is disposable support material and wouldn't work well if I was doing a dual color print I think. For now at least I can print the object without having to use <shudders... /> makerbot or something.

Happy holidays everyone.

[Ola]

I had similar problems. There is a workaround that works but is not user friendly.

http://forum.simplify3d.com/viewtopic.php?f=23&t=2075

Pray that next update will include purge walls!