Keeping PVA going when its used sparingly

[moyesboy]

I have done some work with soluble supports that was quite successful.
With the latest simplify 3D we can create supports in the normal material and then just add the final layers of the support in PVA.
This sounds great.

However I found the PVA sitting in the heated nozzle degrades unless some PVA is printed regularly.

Is there a way using the existing features in simplify 3D to print a bit of PVA external to the model, on a tower, or an ooze shield or whatever to prevent the degrading - so it will print nicely on the dense layers of my support structure?

I'm not having great success with normal supports. I either get a rough knitted sweater type finish on the supported surfaces, or I get supports that are very difficult or impossible to separate from the part. Supports with some dense layers at the interface were particularly impossible to separate. I was promised with simplify 3D I could get a much improved finish on supported surfaces - but so far I only managed that with soluble supports.

Maybe I can print the supports in a rigid insoluble material that just doesnt stick to my part material? what combinations of materials might work like that?

[brian442]

You could use an ooze shield or even a tall skirt where you pick what extruder is used for the skirt

[nickfrats]

PVA crystallizes inside the nozzle if kept at full temperate. What you need to do is add a tool change script so that the temperature drops to around 180 deg C (thats the sweet spot for me but could be higher or lower depending on the PVA print temp) so this doesn't happen. With PVA you especially need to have a prime pillar build up with the part so you prime the nozzle after it cools and heats up again.

As to your last point it really depends on the material you're printing with. But generally speaking if the materials don't stick to each other, you just end up with a mess of spaghetti because your layers won't print correctly.