In recent years the technical characteristics of additive manufacturing (also called “3D-printing”), including its production technologies, and the production units and materials, have undergone rapid development. However, post processing of additive manufactured parts still poses somewhat of a technical challenge. In many cases mass finishing and shot blasting allow creating the required surface finishes on AM work pieces in a cost-efficient manner – as long as these finishing methods are adapted to the unique requirements of additive manufacturing.
Additive manufacturing has long outgrown the stage of just being a prototyping technology and is now on the verge of becoming a system for low volume production of standard products. This unique manufacturing method is highly effective when it comes to the customization of work pieces and the flexible and fast production of small lots of geometrically complex components. It is equally effective with metallic materials, plastic, composite materials, ceramic or glass; in fact, the raw material selection has more or less become open ended! Post-production operations like the removal of support structures, surface smoothing, edge radiusing, high gloss polishing and surface preparation– all require consideration in every single process stage for achieving acceptable surface finishes. Factors to be taken into account are the actual AM technology used for creating the parts, the grain size, tolerances in the applied material layers and the work piece positioning in the production chamber.
Mass finishing – a surface treatment technology for many applications
Different methods for finishing the surface of additive manufactured parts are available. Because it offers wide treatment possibilities, mass finishing is the preferred surface treatment method for AM parts made from plastic or metal. Depending on the work piece shape and size as well as the technical specifications, the required surface finishes can be achieved with single piece or batch processing of multiple work pieces. In any case, it is important to take the required surface finishes already into account during the design process.
Rösler, a global leader in the field of shot blasting and mass finishing, including the machines themselves, processing media and compounds, has been working on the surface treatment of AM parts for several years. The company is not only partnering with renowned companies in this new industry but also cooperates with various research organizations. The Rösler test centers around the world have successfully developed finishing processes for different work pieces from different industries. These include, for example, the consistent and cost efficient surface finishing of cranial plates using a centrifugal disk finishing machine. During the 3-stage process, precisely defined surface areas on these implants undergo a surface grinding and smoothing operation. Likewise, for the aerospace industry a method for finishing AM produced turbine blades was developed. Other examples of successful finishing applications for AM parts are the shift lever on E-bikes, the mold core of injection molding tools, heat exchangers and sensor housings.