Vapor Smoothing

Parts printed with Multi Jet Fusion technology have a chalky, sandy appearance because the parts are produced from a powder stock. For many applications such as electronics housings, early prototypes, and brackets, this is not a problem because the parts will not be seen and the aesthetics don’t matter and extra strength may not be needed. There are two main reasons that engineers choose vapor smoothing: appearance and material properties.


How it works

If you were to look at the surface of an MJF printed part with a microscope, you would see that the surface is made out of millions of partially fused polymer balls, about 60 microns in diameter. These polymer balls form microscopic mountains and valleys which make the surface appear rough. When parts are vapor smoothed, they are hung in a special machine that surrounds the part in a cloud of solvent which causes the micromountains to dissolve and fill in the microvalleys. Once dry, this new surface is smooth and glossy.


  • Vapor smoothed parts are glossy in surface sheen, similar to how an injection molded part would look. The smooth finish can be semi reflective and also serve as a better base for other finishing techniques such as paint, Cerakote, and aesthetic chrome.
  • Vapor smoothed parts offer a better surface for product stickers adhesion. Stickers do not adhere well to the raw MJF finish.
  • Layer lines, especially when parts are dyed, are very difficult to see on a vapor smoothed part.

Material Property Improvements

  • Improved tensile strength and elongation at break.
  • Can be sterilized in an autoclave for medical use
  • Biocompatible
  • Surfaces sealed from moisture ingress
  • Allows MJF parts to be used in food industry
  • More easily cleaned
  • Dimensionally stable; does not add or remove thickness or cause warping
  • Keep in mind that parts still need to be suspended in the vapor smoothing machine, which will cause a blemish on the contact point


The standard raw grey MJF finish can be lighter in some areas and darker in others, making it difficult to see engravings, logos, and fine features. When parts are dyed black, the color is the same everywhere and all of your design features will stand out more clearly. To keep labor costs low and batch-to-batch color consistency identical, we use a Girbau automatic dyeing system. This system uses a special process to ensure dye concentration levels, dye temperature, and agitation of the dye are all performed repeatably. This ensures that an order made in April is the same uniform shade of black as your January order. Manual dyeing often results in splotchy coloring due to uneven rinsing or puddling on the part surface, a brownish color instead of black, or simply a different shade of black which varies from batch to batch.

It is possible to dye MJF parts colors other than black. Because MJF parts start as a gray color, they can only be died dark colors such as dark blue, dark purple, or dark green. If a precise or lighter color is desired, please consider using our Cerakote service, in which we offer standard colors in stock, or custom Pantone colors.



Design for Additive/Cost Reduction

Design Services