Vapor Smoothing

Multi Jet Fusion (MJF)


One of the most exciting secondary finishing techniques GoProto employs on our Multi Jet Fusion parts is BLAST Vapor Smoothing. This process uses the AMT PostPro3D smoothing machine to expose parts to a vaporized solvent gas, which reorders the surface molecules to smooth the part without dramatically affecting the dimensions ( it reduces the part dimensions by roughly .4%).

Not only does this process improve the surface finish of the parts, but tests have shown that the parts are also made more tough, elongation is improved, resistance to liquids is improved, and the part is sealed better, which provides for better surface adhesion for gasketing and suction and provides an excellent base for adding paint, Cerakote, hydrographics or clear coat.

The BLAST process is a physical-chemical-based process that can smooth a wide variety of thermoplastic polymers that are printed in MJF, or FDM 3D printing technologies. The process is non-line-of-sight and can smooth complex internal cavities of polymer parts. The PostPro3D technology is highly controllable, allowing reproducible results with no degradation of a parts’ mechanical properties.

Using a series of pre-defined parameter sets and algorithms, PostPro3D® achieves for the first time a surface finish that matches injection molding techniques. This enabling technology reduces lead-time, cost of manufacture, operational and maintenance costs providing our customers the ‘missing piece’ in the digital manufacturing chain. PostPro3D® makes part surface finishing cost and speed competitive for high volume production. This white paper details the results of extensive testing carried out on HP’s MJF PA12 material.


PostPro3D has been designed to process thermoplastic polymer materials. Currently the technology can process Polyamide (Nylon) (6,11,12), Flame retardant Nylons, Carbon/Glass filled derivatives of Nylons, Thermoplastic Amide (TPA), Thermoplastic polyurethane (TPU), and Thermoplastic Elastomers (TPE). This white paper focuses on HP’s Nylon 12 material.