PVA (Polyvinyl alcohol) the plastic that’s afraid of water
Today we are going to be starting a multipart series looking at some non-standard materials that are printed using Fused Deposition Modeling (FDM).
PVA (Polyvinyl alcohol)
This type of polymer dissolves in water!! FDM printers which have two nozzles can print in PVA and usually ABS simultaneously. When the print is done the model can be submerged in water. The PVA will dissolve leaving the ABS portion of the model intact. The advantages are the ability to print models with overhangs. This method can also be used to print floating or movable parts.
This cube was printed in gray ABS and off-white PVA by thingiverse user Tony Buser.
After printing it was submerged in water.
The PVA dissolved and the ABS remained. This allowed the Hilbert cube containing many overhangs to be printed.
How it’s made
PVA is produced through multiple. However, the starting compound is ethylene gas. So, where does ethylene gas come from? Well it is actually produced by some plants when their fruit ripens. It can also be produced from ethanol. These methods are just too expensive for commercial production. So, it’s made from you guessed it oil. However, it is able to be broken down by some types of bacteria making it biodegradable.
Type of 3D printing which utilizes material: FDM (Fused deposition Modeling)
Usually printed with dual extrusion as a support material.
Most printers utilize 1.7mm filament, some use 3mm filament
Strength: Weak and water soluble. Used as structural support for other materials.
Post Processing: PVA support material can be removed by submersing the model in water. This allows the PVA to dissovlve.
Suggested Printing Temperature: 160-175 °C DO NOT EXTRUDE AT HIGHER TEMPERATURES!
The accuracy at which temperature is controlled is dependent on the printer.
Special Considerations: PVA starts to absorb water from the air as soon as it is opened. For those of you in humid environments the effect will be greatly increased. I suggest resealing the PVA in a bag using a vacuum sealer when not in use. This will allow it to last much longer.
Renewable Resource: No
Starting material= oil
Cost: $88 -$90 a kg
Favorite Source: Ultimachine both 1.7mm and 3mm filament available in many sizes.
Color: PVA is usually only available in it’s natural color off white.
Example: This ABS gear mechanism was produced in one print with PVA as the support material. It has moving parts!
Posted on June 3, 2013, in 3D Printing and tagged 3D printing, ABS, acrylonitrile butadiene styrene, FDM, Fused Deposition Modeling, Printers, Printing, PVA, Renewable resource, Zelda. Bookmark the permalink. 4 Comments.