Hybrid Manufacturing

The hybrid manufacturing hardware segment – as we know it today – came into existence in 2013 (announced – as is often the case, by an excellent article published on The Economist). The magazine correctly identified the launch of DMG Mori’s Lasertec 65 system as a key turning point, which enabled traditional machine tool manufacturers to begin embracing an additive approach. Before that, DED-type technologies were used primarily for cladding and part repair. With this new approach, many began to see DED as a key technology to make new parts as well.

As explained by Fabrisonic, developers of a unique, ultrasound-based hybrid manufacturing technology, many 3D printers in the metal AM space are migrating to a hybrid additive manufacturing approach to satisfy stringent industry requirements.  While not formally defined with ASTM terminology, hybrid additive manufacturing is generally considered to be a combination of additive manufacturing (3D printing) and subtractive manufacturing (CNC milling) technologies in a single machine.

Hybrid solutions are often built using a base CNC mill to which the additive technology is added.  For instance, directed energy deposition (DED) additive technology is used for solutions developed by hybrid manufacturing in a wide range of hardware systems such as those produced by DMG Mori and Mazak.  Similarly, sheet lamination additive techniques are used for Fabrisonic’s large-scale hybrid printers, while a laser powder bed based (PBF) SLM approach is implemented by Japanese company Matsuura.

Critics of the hybrid approach disapprove that hybrid systems combine two expensive processes into one machine, wherein only one technique can be used at a time, rather than in parallel systems. The answer to that question is not definitive and depends on the volume and variability of production. While it makes perfect sense to use separate machines for high volume production, the lower volume, high variability jobs are seen by most 3D printers are best tackled with a hybrid approach.

Several hybrid manufacturing hardware systems enable the use of a multiplicity of tools, including tools for inspection and metrology in a single machine. This also means that parts can be finished and milled during the additive process, enabling a greater variety of geometries. In addition, hybrid manufacturing is significantly faster than powder bed additive manufacturing for a wide range of very large parts, due to high deposition rates and production of near net shape (NNS) parts which are rapidly milled into a final geometry. This approach also makes AM significantly faster than any pure CNC system.

Hybrid systems can and have also been used for parts repair. Hybrid enables fixing of an existing component, milling damage areas, and immediately adding material to replace features.  In addition, hybrid manufacturing processes can enable faster and more accurate surface finish: most traditional metal additive processes print parts slightly larger than designed to account for the variable surface finish created when metal powders are printed. This surface variability requires many traditional additive parts to undergo complicated post-build processing.  There is an entire cottage industry developing around simply finishing parts (a hybrid process in itself).  By coupling the additive technique seamlessly with CNC milling, all internal and external surfaces can be milled to traditional CNC finish.  Parts such as high-efficiency heat exchangers come off the machine ready for use.