Just as you’re (perhaps) getting used to additive manufacturing (AM/3D printing) by understanding its capabilities and changing your design process to make the most of it, along come hybrid systems.
Metal parts manufacturing has involved casting, die-casting, forging and/or machining for many years — all well-understood processes for engineers to apply DFM (design-for-manufacturing) principles. Additive manufacturing added some new capabilities and perhaps new DFM rules.
Even with additive manufacturing, parts still require some additional steps — cleaning, finishing, secondary machining, and others. The fewer the separate steps, types of machinery and required handling, the faster, cheaper and more precise these parts can be. The solution may lie with hybrid AM/subtractive equipment.
Before commanding the software to perform the right step at the right time, designers must identify which sections of a part should be “grown” and which require subtractive action. As designers begin to understand the potential, they will learn to define the surfaces that will interface with other parts and therefore are most likely to require subtractive work to create a fine surface finish. This often requires the design of a ‘near net shape’ part, with additional sacrificial material to be machined off in a secondary, subtractive process. designers must develop knowledge of how much extra to add, and where, to accommodate this need.
Autodesk’s Netfabb software helps manufacturers prepare parts for both additive and subsequent subtractive manufacturing processes. It helps designers to design and plan near-net shapes for additive and subtractive manufacturing, which can then be exported directly to Autodesk PowerMill® where to create CNC programs on the features and surfaces.
Although design freedom is a key benefit of this technology, designers still need to be careful about the build process as the support structures can be the tricky part. A dramatic benefit of hybrid technology is elimination of support structures entirely if the part is properly oriented and built on a 5-axis machine.
With Creo 4.0, introduced with input from Stratasys, users can define the materials and colors a plastics 3D printer can handle in real time. In the future, such manufacturing awareness, embedded in the CAD system, can be expanded to cover the multi-processing capabilities of metal hybrid manufacturing.
Most parts are still connected to one another via screws, bolts, gaskets, etc. Being able to evaluate dimensions mid-stream in an AM build would allow the machining part of the process to actively create the necessary flat mating surfaces or even datum for precise alignments. A first step toward adding this feature to hybrid systems is underway, as developers at Dassault Systèmes SOLIDWORKS have teamed up with Geometric Americas to offer CAMWorks software. The latest version of Geometric CAMWorks, embedded in SOLIDWORKS, introduces “tolerance-based machining” into traditional CNC (computer numerically controlled) systems. In-process machining would save time and improve accuracy on hybrid AM/subtractive systems.
You don’t have to wait to install combined additive/subtractive tools on your manufacturing floor. More than eight systems are already for sale, with additional options available for build-your-own; all are based either on power-bed laser sintering or direct metal deposition, but vary in the details.
- Additive Industries – MetalFab1
- Sodick – One-Process Machine (OPM) 250L metal 3D printer
- Optomec – LENS Machine Tool Series
- DMG MORI USA – LASERTEC 4300
- Hybrid Manufacturing Technologies – AMBIT multi-task system
- Mazak USA – markets 5-axis INTEGREX i-400AM DMD system
- Fryer Machine Systems – includes an Optomec LENS DMD print engine in its new LaserFab hybrid machining unit
- Matsuura Machinery – LUMEX Avance-25
You can learn more about Additive Manufacturing Design through this workshop video series by ASME (AM3D Conference 2016).
>>Read more by Pamela J. Waterman, Digital Engineering, December 1, 2016