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PVA Powder Pre-Drying for Extruding


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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.

Best regards,

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 ?

Best regards,