In its centre of competence, the SKZ research team for plastic materials in Würzburg, Germany, concentrates on research and training in the field of 3-D printing. A large portion of the work concerns post processing. To better deal with this subject SKZ recently purchased an S1 shot-blast system from AM Solutions – 3-D post processing technology. Among other things SKZ analyses the effects of different blast media on the surface finish as well as their efficiency and the consistency of the shot-blasting results.

As one of the largest research institutes in its field the SKZ centre for plastic materials studies not only different materials but also the underlying manufacturing processes. In this respect the 3-D printing technology, which in recent years has undergone exponential growth, plays a significant role. For this reason, SKZ maintains a separate centre of competence, the centre for additive manufacturing (AM), in Würzburg.

This organisation handles not only numerous research projects but also develops training programmes to familiarise interested companies with the 3-D printing technology, be it for prototyping but also for volume production. Especially, when it comes to producing large work piece volumes, the post processing of the 3-D printed components is a key manufacturing stage. To be able to study post processing in more detail, SKZ invested in a S1 shot-blast system supplied by AM Solutions – 3D post processing technology.

Kevin Popp, senior scientist for AM at SKZ explained: “In our research with new materials for powder bed based AM, the post processing stage is an extremely important aspect. For example, right now we are studying the effect of different blast media on the surface finish of different plastic materials. For this purpose, SKZ is using the S1 system.

“We are particularly impressed by how adaptable this system is for our post-processing activities, for example, how simple it is to change over the blast media. With its easy, uncomplicated blast media exchange the S1 allows us to create quick and direct comparisons between different media such as glass, ceramic or poly beads.”

Blast nozzles
With a CT scan the effects of different blast media on the surface finish can be precisely analysed. For example, in the case of orthotic or prosthetic implants micro fine glass debris, created by the impact of glass beads on the workpieces, must be prevented at all costs. For such applications other blast media like poly-beads are much more suitable. SKZ also analyses and documents the surface qualities produced by different processing parameters, for example, the settings of the blast nozzles. All these empirical findings are extremely valuable for companies who want to establish 3-D printing in their manufacturing operations.

Mr Popp continued: “For volume production the repeatability of the results and time are essential parameters, which we study carefully. With our manual shotblasting operations the surface finishes were all over the board. The S1 produces consistent surface finishes on large workpiece volumes, even on extremely complex components like brain gears with their delicate gear tooth geometries. In the past it took us a whole day to blast 300 pieces and the results were highly inconsistent. Today we need just 15min for the same workpiece volume, with excellent, consistent surface finishes.“

Of course, such information is very important for the creation of suitably efficient process chains. He added: “We consider ourselves as pathfinder for AM and want to guide the people to this technology in a sensible manner.”

For a research institute like SKZ good cooperation with its partners is essential. Mr Popp concluded: “With AM Solutions we have found a partner with decades of experience in post processing, with whom we can openly discuss our issues and jointly develop suitable solutions. Such a wealth of knowhow is a big help to us, and the short geographical distance between our two organisations allowed us to test the machine and the blast media beforehand in Untermerzbach.”