Post-Processing Considerations for 3D-Printed Components

Mass Finishing technology has been used to refine traditionally machined parts for decades. Many technologies, from vibratory bowls to high-energy centrifugal discs, drag finishers, centrifugal barrels, and blasting equipment, have been used to remove burrs and parting lines as well as grind and smooth the surface of parts of various materials. All these technologies use a variety of process media that contain abrasives. This process media comes in many shapes, bonds, and sizes. These machines replace the traditional hand-sanding method by using mechanical action and forces.

Most additively manufactured components are designed to be printed to the final required dimensions without consideration of the final surface finishing and post-processing steps needed. Mass Finishing equipment is a nondiscriminatory process, meaning the material removal is equal across the accessible surface of the part. Material removal using this equipment can be between .001 - .005 of an inch. Therefore, consideration of the final part dimensions and the function of the part must be given in the design phase of those parts, especially to parts with complex geometries or interior areas that require finishing. The component could be designed in multiple parts or with built-in masked regions that can be removed after post-processing. These masked areas can protect critical part dimensions and edges that may be affected in the finishing process. With additive manufacturing, we can now adapt to the final finishing process, allowing a finished part that meets all dimensional requirements.

The advantages of mass finishing are apparent. Many pieces can be processed at one time, thus eliminating many hours of tedious hand work, which will lower the per-piece cost of the parts. Traditional mass finishing (centrifugal barrel, disc, vibratory bowl) are not well suited for complex geometries. The gross material removal and loss of geometry to critical dimensions is pronounced on outside, accessible dimensions, sometimes leaving the inside dimensions virtually untouched.

One technology uniquely suited to complex geometries is the MV machine. When considering finishing options, engineers have either allowed for dimensional changes from finishing or opted to hand finish, discriminately, to avoid any changes in final dimensions. Walther Trowal has developed processes utilizing MV technology that consistently produces highly homogeneous surface finishes on workpieces with complex geometries, such as thin, fragile vanes, as in an impellor or femoral component with a "box." Even difficult-to-reach areas receive a consistent finish.

Walther Trowal has extensive experience in finishing additively manufactured components and has worked with many companies on developing customized finishing solutions. Don't hesitate to get in touch with us for more information.