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Vapor smoothing uses a chemical polishing process to smooth and seal the surface of 3D printed plastic parts to improve the surface quality and enhance part performance, with minimimal effect on the dimensional accuracy (< 0.4%). 

The process treats both internal and external surfaces, making it an excellent choice for parts with complex geometries or hollow features. 

Vapor smoothing is compatible with a wide variety of thermoplastics including Nylon PA12, TPU, Polypropylene and composites.

AMT PostPro Vapor Smoothing

AMT's PostPro chemical vapor smoothing technology is used for the vapor smoothing process, which uses a chemical vapor to liquefy the surface of the material. This process smooths out the peaks and valleys creating a smoother, more consistent surface. 


When the procedure is complete the processing chamber is heated to evaporate any remaining solvent, leaving no chemical residue on the part.

Benefits of Vapor Smoothing

AMT Vapor smoothed helmet (courtesy of AMT).jpg
Enhanced Mechanical Properties

Vapor smoothing reduces surface porosity and crack initiation sites, which increases elongation at break with no loss of tensile strength.

Post-AMT vapor smoothing (Courtesy of AMT).jpg
Improved Surface Quality

Vapor smoothing smooths and seals the surface of a part, giving it a finish that is similar to injection molding. Parts produced with Multi Jet Fusion can have the surface roughness average (Ra) reduced from 6-13μm to 1.5μm.

vapro fuse bicycle seat (Courtesy of AMT).jpg
Dimensional Accuracy

The process has a minimimal effect on the dimensional accuracy of the part, with no more than 0.4% dimensional change. The process also does not degrade the mechanical properties of the part.

AMT vapro smoothed TPU (Courtesy of AMT).jpg
Watertight and Airtight Surface

The surface of treated parts are completely sealed, making them impermeable to liquid and gas.

TPU-Before-and-After-PostPro-Chemical-Vapor-Smoothing (COurtesy of AMT)_edited.jpg
Preparation for Surface Treatment

Vapor smoothing can be combined with additional surface treatements to improve the end result such as dyeing, cerakote, or metal plating.

AMT Vapor smoothed prosthetic (courtesy of AMT).jpg
Reduced  Bacterial Growth

The reduced surface roughness of vapor smoothed parts reduces bacterial growth, making them suitable for use in the medical and food industries.

Material Compatibility

Vapor smoothing is compatible with most thermoplastics including Nylon PA12, Ultrasint TPU, Polypropylene, Nylon 12 glass bead, and composites such as Onyx.


  • Reduces surface roughness by 1000% or more.

  • Improves shore hardness, elongation-at-break and tear resistance.

  • Maximum shrinkage of 1%.

  • Sealed surface.

Nylon PA12, PP

Rigid Plastics
  • Reduces surface roughness by 800% or more.

  • Improves tensile strength, yield stress and elongation-at-break.

  • Increased functionality.

  • Sealed surface.

Glass filled, carbon filled

  • Increased durability.

  • Improved elongation at break and tensile strength.

Learn more about Tempus 3D Printing Solutions

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