PVA Powder Pre-Drying for Extruding
We'd like to ask a question regarding PVA powder pre-drying for later extrusion in a Composer 450.
We got an answer before for this, to dry it in a furnace for 5 hours, on 90°, but our furnace is not usable at the moment. Is it also sufficient to dry the PVA powder in a near-vacuum environment and also with added silicate gel?
Looking forward to your reply.
Matt from PTE3D
Hello Matt @pte3d ,
Thank you very much for your detailed question.
I must say I am not a specialist of this topic, but I just did some research.
If I understand correctly, drying under vacuum is more effective (fast) than 'normal' drying. More moisture can be extracted in less time. However, I think that some heat still has te be applied.
I do not think that vacuum only, at room temperature, can extract enough moisture from the polymer. The way I see it, is that the molecular chains of the polymer have to relax under heat, to let moisture escape. But again, I have not studied this topic in great depth.
Do you have access to a moisture analyzer ? You could assess the vacuum drying process with this ; the target residual moisture content is 0.05 or 0.025%wt.
What do you think ?