Vapor Smoothing vs. Vibratory Finishing: Which Surface Finishing Process Should you Choose?

In order to achieve a polished and refined surface on 3D printed parts, engineers use a broad range of industrial finishing techniques including coating, sandblasting and hand finishing methods. Although 3D printing allows for the production of intricate and complex parts, the initial prints that come straight from additive manufacturing often exhibit rough surfaces and noticeable layer lines, particularly in parts produced using Fused Deposition Modeling (FDM). One of the final stages, post-processing, is undergone to take the rugged and unfinished surface and alter the part’s material surface by adding or removing layers of the part. In this article we will introduce you to two well-known surface finishing processes: Vapor Smoothing and Vibratory Finishing. You will learn all about the process of the methods, the advantages and disadvantages, and which method is best suited for your individual purpose.

Process

Vapor Smoothing

Vapor Smoothing, also known as Chemical Vapor Smoothing, is a technique that involves exposing the printed parts to vaporized solvent. The industrial Vapor Smoothing process requires carefully suspending single or multiple parts in a closed chamber for maximum exposure. A chemical solvent blend, such as FA 326, is injected and sprayed into the chamber, where it condenses and hardens on the part, removing surface irregularities through a controlled melt. As the chamber temperature increases, the residual solvent evaporates and is recovered. The final part becomes watertight and retains its smooth internal cavities, accurate dimensions, and original material volume. For optimal results in Vapor Smoothing, it is recommended to conduct the process in a controlled environment using industrial-grade equipment specifically designed for 3D printing Vapor Smoothing. For those interested in a DIY approach, Vapor Smoothing, or in this case called Solvent Dipping, can be achieved using acetone or ethanol as chemical solvents. However, it is essential to exercise caution and ensure proper safety measures and equipment are in place.

Vapor smoothed part on the left, versus standard finish on the right (Photo credits: ProtoLabs)

Vibratory Finishing

Vibratory Finishing, on the other hand, does not use chemicals for surface treatment. Instead, it relies on an abrasive medium to enhance the surface of 3D printed parts. In this process, several 3D printed parts are placed in a vibratory tub filled with a selected abrasive medium and a lubricating fluid known as the compound. When the machine is turned on, the tub begins to move, creating mechanical friction between the part and the abrasive medium. This subtractive process results in minimal and gentle removal of the outermost layer of material, improving the surface quality of the part. Vibratory Finishing requires special measures and equipment and offers two methods: the Vibration Method and the Tumbling Method. The Vibration Method is particularly suitable for larger, less detailed objects and achieves the desired result much faster. However, with the Tumbling Method, the movements are much slower and gentler, making it suitable for detailed and delicate parts.