How vapour smoothing takes the surface quality of 3D printed parts to the next level

By Matt Hatch

With vapour smoothing, 3D printed parts attain a surface finish that could otherwise only be achieved through injection moulding.

The defining characteristic of modern production is the constant further development of its capabilities and capacities. For example, state-of-the-art processes and materials in additive manufacturing (AM) are continuously opening up new and previously untapped sectors and branches of industry.

At the same time, the differences between additive manufacturing and injection moulding, for instance, are hard to ignore. While additive manufacturing excels in the extensive freedom it allows for product design, in particular, and is therefore especially suited to one-off or low volume production, injection moulding is known above all for its advantages in the production of high volumes. However, in the past another key difference between these two processes was the surface quality, which was considerably better with injection moulding than with 3D printed parts, due to the nature of the process.

Unfinished components produced by additive manufacturing typically have a rougher surface, for example, and tiny gaps within it. In the medical sector – indeed anywhere that parts come into contact with fluids or where easier and thorough cleaning may be a decisive quality feature – the possible applications of additive manufacturing and injection moulding have so far diverged.

Vapour smoothing builds bridges between additive manufacturing and injection moulding

In order to exploit the advantages of additive manufacturing while achieving the surface quality of injection moulding, companies are relying on the vapour smoothing process. Using this technique, 3D printed parts that may have been produced using selective laser sintering and multi jet fusion, or even fused filament fabrication, are vapour smoothed and refined.

To put it simply, during the automated process, surfaces that may be rough due to the AM process are smoothed and sealed in a smoothing chamber, which can hold several components at one time. 3D printed parts made of thermoplastics and elastomers are heated first. Next, solvent is added which, through evaporation, smooths surfaces and seals even the tiniest cavities in the component's structure.

As well as smoothing the parts, their physical characteristics are also changed – they have an improved elongation at break, for example. What's more, the part smoothing process has no negative impact whatsoever on the parts' properties. To give some  examples of use, the improved leak proofing attained by the vapour smoothing method gives components important properties that make them suitable for use as tanks, fluid-bearing pipes and ducts, valve covers and oil sumps, to name a few examples. In addition to these possible uses in the automotive sector, parts rendered sweat-proof thanks to vapour smoothing are also ideal for the medical sector and numerous other industrial applications where ease of cleaning of plastic parts is a major concern.

Consequently, vapour smoothing can indeed be seen as a bridge. The process opens up additional opportunities for 3D printing, creating advantages that were otherwise known only in the world of injection moulding.