Vapor Polishing/Smoothing FDM Parts

We are often asked about vapor smoothing, and wanted to write a quick article describing how it works, as well when we recommend using it.  The process involves suspending FDM prints in a cloud of solvent vapor, which condenses on the print in a uniform film, melting the outer surfaces of the part, smoothing and fusing layers together.  It also greatly enhances the sheen of the part, resulting in a glossy finish.

The vapor smoothed part (top) is glossier than the raw part, with slightly reduced layer lines.

What are the Results?

As you can see, cosmetically, it’s a pretty subtle change.  The layer lines are blended somewhat, but still mostly visible, especially on a surface with lots of curves like this.  The biggest difference is the surface glossiness that results from the process.  It’s definitely NOT a substitute for paint for parts that need an attractive cosmetic finish.  With the addition of mechanical finishing such as sanding or media blasting, the results can be a bit more dramatic, however those processes are often very time consuming and thus expensive – if aesthetics are the goal, paint is typically the more cost effective and professional option.

A painted FDM part from POP

Although the results are generally subtle, vapor smoothing can be of significant benefit in certain scenarios.  For example, by better fusing the outside layers of a part together, small features such as tabs can increase in strength and snap-resistance relative to unpolished parts.  In addition, by fusing the outer layers together with the solvent, the part becomes more water-resistant (although we would still advise customers that FDM parts are not generally considered water tight – PolyJet printing is a far better option if that’s a requirement).  

You can see more details about the process in Stratasys’ video below.