Post Processing For Polymer Additive Manufacturing
Post-processing of solid-state powder sintering can lead to difficult, time-consuming support material removal. Post-processing can often limit the design, since support material in small areas can’t be removed with current equipment. The same difficulties can be encountered with liquid-phase beds, although to a lesser extent. A new vacuum process has overcome the problem of material removal. Examples of results are shown below.
Powder Bed Fusion Material Removal
Liquid Phase Bed Fusion Material Removal
Originally Printed Gear
Gear After One Hour
Gear After Three Hours
The gear shown above was treated in a 3% sodium hydroxide solution, pulsing a vacuum to produce vapor within the part every 15 seconds. The VCN vacuum removes the spent solution from the gear’s internals and introduces fresh solution to continue dissolution. After 3 hours, the gear was completely cleaned, and all the gears rotated freely. Generally, this part takes 48 hours in a 10% sodium hydroxide circulation bath to remove all the material.
The internal removal of FDM support material from the parts shown on the left takes 1 to 2 days in an agitated bath. The part is shown on the right after 20 minutes in the VCN process, and an additional 20 minutes removed all the internal material. Check out the video below to see this process in action.