Dual Extrusion - Printing Raft only?

[Tetraodon]

I'm a bit unfamiliar with using dual extrusion and am wondering - I only want to print the raft with the dissolvable filament, and want to print the rest of the model with ABS. Will the extruder doing dissolvable filament continue to be heated for the rest of the print even though it's only being used for the raft? Or would I have to use two processes and turn off the second extruder once the raft is finished?

If the extruder stays on - will I need to do an ooze shield? It's a big object and the ooze shield takes up a lot of plastic when that extruder is only being used for the first few mm. Sorry for the silly question!

[JoeJ]

I think I'd try to setup 2 processes for this one. That's probably the easiest way to control when the extruders are turned off.

[Tetraodon]

So it looks like the Ooze shield starts after the raft's finished - meaning my left extruder (ABS) just oozes the whole time while the right is spending 30 mins printing the raft alone - which appears to have left that extruder blocked.

So how do people print their rafts without having ooze problems? Height adjustments (for turning layer processes on and off) /appear/ to happen after the raft, meaning I can't do much with turning the extruders on/off based on the raft itself.

So my only option seems to be designing an object to work as a raft, and making two processes based on the models.

But I'm a bit lost on how people print rafts if both extruders are going and there's no Ooze shield, causing blockages?

[JoeJ]

Well the raft gets thrown away in the end, so I don't particularly mind if there is some oozing on it

But also, you can manually retract the second extruder in your starting script so that there is less plastic in the nozzle to ooze out if you want. Or try having a lower temperature for the first few layers.

[Tetraodon]

Thanks regardless Unfortunately I've given up on the idea as the HIPS was warping just as bad (if not worse than) as the ABS. Decided to go from Gluestick to the ABS slurry - still getting warping, but at least it sticks to the plate!

How do you go about minimizing seams/retractions on mechanical parts (eg parts that slot into each other) which require accurate sizing - preferably without having to sand them down?

[Tetraodon]

I'm having two major issues (factory file attached with both objects):

- I've managed to reduce the number of retractions but am still getting some big seams small parts (which need consistency in size). You can see one of the designs I'm having issues with in the attachments.

- I'm trying to print this spiral pattern and am having no luck at all with it. I'm assuming what's happening is the layers aren't having time to cool, but despite slowing them down (printing two things at once, setting it to a min of 40 seconds per layer slowing down to 5%, slowing printing speed overall to 3800mm/min), I'm still having it go blobby as it prints. Having printed larger objects with overhangs greater than the spiral, I'm pretty sure the printer can handle the overhang itself, as you can see on the far left overhang. But once the area gets smaller, it starts to have issues.