Jeff's MCAD Blogging
Jeffrey Rowe has more than 40 years of experience in all aspects of industrial design, mechanical engineering, and manufacturing. On the publishing side, he has written well over 1,000 articles for CAD, CAM, CAE, and other technical publications, as well as consulting in many capacities in the … More »
Additive and Subtractive Processes Equal Manufacturing Innovation
August 20th, 2015 by Jeff Rowe
With multitasking an increasing fact of life for us all, it’s no surprise that machine tools continue to evolve into increasingly multifunction machine platforms, as well.
Let’s be honest, though, multifunction machines are not exactly new. For example, machines with processes that work together providing several functions, such as milling, turning, drilling, tapping, measurement, and EDM have been around for a number of years as requirements have changed.
I’ve also seen a number of interesting things on the exhibit floors at manufacturing trade shows, such as RAPID and IMTS, that employ traditional multifunctional capabilities, but have been most intrigued by a new emerging class of hybrid 3D printers that employ both additive manufacturing (AM) and subtractive (conventional machining) methods. Some of these innovative hybrid machines follow.
Hybrid (Additive & Subtractive Manufacturing) Machine by DMG Mori
DMG Mori (Laser Tec 65) – This hybrid machine integrates laser deposition welding and 5-axis milling. Since the machine deposits metal through a powder nozzle, the company claims it is 20 times faster than generation in a powder bed. The 5-axis milling machine is from DECKEL MAHO and has an integrated laser head HSK-interface. Change between milling and laser operations is automated, and the machine has a large work envelope that can handle pieces up to 25.6 in. diameter, 14.2 in. height, and 2,205 pounds. Depending on the laser an nozzle geometry, the machine can process wall thicknesses ranging from 0.004-0.2 in.
Hybrid Manufacturing Technologies (AMBIT) – This has been available since September 2013 by providing AM for CNC and CNC for AM. It does this by adding an AM head with capabilities that converts a CNC machine to a hybrid machine that can change between manufacturing processes, similar to changing milling cutters. It is available with laser processing heads for powder-fed cladding, marking, drilling, and re-melting. It can accommodate manual or fully automatic tool/process changeover from milling to an expanding range of AM processing heads.
MC Machinery Systems (LUMEX Avance-25) – This machine is the product of a subsidiary of Mitsubishi Corp. in partnership with Matsurra Machinery Corp. The LUMEX Avance-25 provides one-machine, multiple processes for manufacturing complex molds and parts by combining metal laser sintering (3D SLS) with high-speed milling. It can create mold die parts in one piece with porous sintering for gas vents, as well as creating conformal cooling channels. The company claims a 60% reduction in production time for creating mold tools because it can create deep ribs with no EDM work.
Optomec (LENS Print Engine) – This is currently still basically a proof of concept where the company purchased a Fadal 3-axis machining center on eBay and outfitted it with a LENS (Laser Engineered Net Shaping) Print Engine, with a process also known as directed energy deposition. It employs a laser and powdered metals for building fully dense structures directly from 3D CAD models. The CAD model is sliced into a tool path that instructs the LENS machine how to build a part. According to the company, the LENS Print Engine can be housed in any suitable machine tool, such as a CNC mill, lathe, machining center, etc.
This platform began a little over a year ago when America Makes challenged Optomec to produce a modular version of its LENS 3D Metal Printing System that could be integrated with conventional metal cutting machine tools, such as CNC lathes and mills. The company seems very interested in scaling the technology achievement beyond rapid prototyping to high-volume manufacturing. Optomec also realizes that to succeed, the technology will have to provide a real and proven cost benefit to a manufacture, and therein lies a major challenge.
An interesting twist on 3D imaging is CGI’s subtractive scanner that is a cross-sectional scanning system for inspecting plastic parts. Parts are potted in a resin. The potted device is then secured and sliced away subtractively in 0.001 in. layers. As each layer is removed, the newly exposed cross-section is scanned. When all layers have been removed, the point cloud from the scanned data is reconstructed into a 3D CAD model and compared with the original CAD data. Although a part is destroyed in the process, it provides excellent data for first article inspection.
Probably the biggest issue confronting multifunction machine platforms is scalability, meaning that small parts are relatively easy to handle, but larger automotive and aerospace parts will continue to be a big challenge.
The integration of multiple manufacturing processes into a single machine platform continues to grow and the possibilities they offer for complex designs and unique materials will continue to also grow in parallel.