3D Printing Scales-Up
Constant innovation in machine design, compatible materials and software is leading additive manufacturing from the prototype shop to the production floor.
While the 3D-printed vehicle remains a dream, the technology also known as additive manufacturing (AM) already has proven its ability to create impressively complex part geometries in concepts such as EDAG’s ‘Light Cocoon’ . AM enabled the exquisite 8-piston brake calipers used by Bugatti, among other boutique components, and AM machines are becoming as ubiquitous as Bridgeport mills once were for advanced-prototype builds. Low-volume series production use has arrived – see VW news below.
Greater scale is on the horizon, driven by constant innovation in machine design, compatible materials and design software. 3D printing technology and applications are exploding in the mobility space, highlighted by the following recent examples.
VW’s binder jetting process
Volkswagen Group is pioneering a new AM technology, known as binder jetting, as part of its production process. The 3D-printed components are manufactured in Wolfsburg, Germany and used in the A-pillars of VW’s T-Roc convertible assembled in Osnabrück. VW has a strategic partnership with Siemens AG, which provides the proprietary software used in the AM process. HP Inc. makes the special printers.
Whereas conventional 3D printing uses a laser to build a component layer-by-layer from metallic powder, the binder jetting process uses an adhesive. The resulting metallic component then is heated and shaped. Using the binder jetting component reduces costs and increases productivity and can reduce mass: VW claims the A-Roc components weigh 50% less than those made from sheet steel.
A key to the process is optimizing the positioning of components in the build chamber. The technique, known as nesting, enables production of twice as many parts per print session. “Using this technology, Volkswagen will be able to develop and produce components faster, more flexibly and using fewer resources,” noted Cedrik Neike, a member of Siemens AG’s managing board and CEO Digital Industries.
The VW Group has invested an amount “in the mid-double-digit-million euro range” related to AM since 2016, according to the company; it operates a 3D printing technical center at its Wolfsburg complex, which also trains employees in the use of these technologies. By 2025, VW aims to annually produce up to 100,000 components by 3D printing in Wolfsburg. Currently, 13 departments at the plant use various 3D printing processes to manufacture both plastic and metal components. Since 1996, VW has produced more than one million 3D printed components, the company said.
Wayland’s next-gen metal AM
U.K.-based 3D-printing technology specialist Wayland Additive is aiming to expand the range of metal-AM industrial applications, including automotive, with its recently launched Calibur3 system. The technique uses a patented process called NeuBeam – an electron-beam based technology hot enough to melt metal powder, housed in a modular enclosure. The Caliber3 machine was designed to operate with low noise and improved operator safety and productivity, the company claims.
NeuBeam was developed in-house by team of physicists specializing in electron-beam technology and industrial systems in the semiconductor industry. It effectively neutralizes the electron beam (eBeam) powder bed fusion (PBF) process to offer greater flexibility than laser-based AM processes, while overcoming the stability issues many users of traditional eBeam AM systems experience, the company claims. In addition, NeuBeam enables metallurgical requirements to be tailored to application requirements, addressing previous limitations of the process. It is capable of producing fully dense parts in a wide range of materials, including refractory metals and highly reflective alloys, many of which are incompatible with traditional AM processes, noted Wayland Additive CEO Will Richardson.
Seat supplier finds 3D solution
Germany-based 3D printer systems manufacturer Genera Printer GmbH is collaborating with adhesives Tier-1 Henkel’s Open Materials Platform to bring AM into scale production in automotive. The partnership centers around Genera’s G2/F2-System for digital light processing (DLP), which the company claims enables a 3D-printed part to move seamlessly from the green state to finished part. Parts printed in the G2 are stored in what is called the “shuttle,” which allows the safe transfer of parts to the F2 finishing unit. The shuttle features a memory chip that stores all the data of the workflow, including the post-processing data of the part. This ensures full documentation of the production process, harmonizing printing, washing and post-curing, according to Genera.
Sam Bail, Henkel’s sales chief for 3D printing, said the goal with AM “is to drive production at scale and we believe that by collaborating with the ideal ecosystem partner the Loctite [owned by Henkel] 3D printing materials will become a significant enabler.”
He referred to a recent example in which the pairing of a Genera printer with Loctite’s 3D elastomeric photopolymer range solved a design-related automotive seat fabrication challenge. Supplier KTM-E Technologies approached Genera with the need to design and manufacture prototype parts with elastic materials to create seats containing a functional lattice structure. KTM-E had concluded that many industrial 3D printers could not produce the prototype parts with the quality and standards required for series production. The solution combines Genera’s printer with Loctite’s 3D 8195 product – one of 10 Loctite 3D printing resins in Genera’s materials portfolio.
“Additive manufacturing is and will be a key technology in manufacturing, not only for prototype parts but also for serial production,” said Florian Fischer, the AM project lead at KTM E-Technologies.
Toyota R&D’s focus
Like most OEMs, Toyota is steadily pushing AM toward volume production and, in the process, finding significant value in it for creating prototype parts and tooling. The automaker’s North America R&D group (TMNA R&D) in Michigan is using AM to shorten long tooling lead time early in the development cycle. In the process AM is helping to reduce tooling costs.
The facility in York Township west of Detroit is outfitted with equipment from 3D Systems, EOS, Stratasys and Carbon 3D. Additive processes performed at the center include fused deposition modeling (FDM); selective laser sintering (SLS); stereolithography (SLA); multi-jet modeling (MJM) and digital light processing (DLP).
Prototype builds are a primary focus at TMNA. Some prototypes are used for appearance confirmation, some for functional checks and still others for workability studies. The models are used to support both traditional vehicle development projects as well as new mobility and advanced development initiatives that Toyota is undertaking.
Tooling-build use of AM includes process jigs that are used to ensure that the vehicles’ exterior emblems are correctly assembled during pre-production trials at the facility. The jigs then are used in Toyota’s North America production operations. Challenges in adopting AM for volume production being addressed at TMNA include matching the properties of the materials currently being used in production operations; being able to scale-up additive output to support high-volume production needs and increasing processing speeds.
Mahle tests materials for AM
Slashing prototype lead times from several months to a few days explains in part why Mahle’s technology group decided to build a new facility for additive manufacturing (AM) processes at its Stuttgart headquarters. The 3D printing center houses the printers, powder-preparation module, testing laboratory and a blasting system for finish machining the components to satisfy internal prototype production as well as automotive and commercial-vehicle customer orders.
“The development of new systems and components has to be much faster today than it was a few years ago, especially when it comes to e-mobility,” Andreas Geyer, head of Process Technologies in Central Research at Mahle, said during a recent press event introducing Mahle’s new AM capabilities. “We are boosting the performance of our existing portfolio through possibilities in production design.”
Another reason for opening such a facility is to enable 3D printing for series production that meets the strict standards of the mobility industry. The focus is on developing and qualifying manufacturing processes for components in thermal management, mechatronics and electronics – for example, to produce transmission and electric motor housings, charge air coolers, oil filter housings and heat exchangers, as well as structural elements, mounting devices and connections.
“We want to be prepared today to find out how we can use an integrated 3D printing [development process] according to automotive standards for later large-scale production,” Geyer said. “This opens up completely new possibilities in product development and manufacturing, because these processes can be used to produce high-performance components that cannot be manufactured using conventional methods.”
The center processes two standard metal materials: aluminum-silicon-magnesium (AlSi10Mg) and stainless-steel 1.4404 alloys. Mahle 174+ aluminum alloy, suitable for pistons in heavy-duty diesel engines with high loads, also was adapted to AM. In addition, a couple of plastics materials can be used on Mahle’s network of 3D printers, Geyer said. “Copper is a material that might be used in the future, but currently aluminum is the important material for heat exchangers,” he added.
Laser powder bed fusion is used to form the component layer-by-layer. Mahle currently can manufacture components up to around 30 x 30 x 40 cm (11.8 x 11.8 x 15.7 in). After the printing process is complete, the finished parts are separated from the base plate and finish-machined by hand.
In a joint project with Porsche and Trumpf last year, Mahle engineers successfully produced and tested high-performance parts such as pistons and charge-air coolers for the Porsche 911 GT2 RS. “This was one of the milestones that also led to our decision to establish our own 3D printing center with our own printers,” Geyer said. The project proved expected advantages of the 3D printing process – namely the elimination of expensive production tools and the ability to create structures otherwise too complex to produce. Commercial-vehicle systems are another focus of the Mahle facility.
SABIC, Local Motors study recycling
A study on the feasibility of recycling scrap thermoplastic parts and shavings from the large-format additive manufacturing (LFAM) process was recently concluded by global chemical giant SABIC and Local Motors, a Phoenix, Arizona-based vehicle startup that champions the use of AM. The joint study explored more sustainable alternatives to landfilling large, printed parts in anticipation of wider adoption of AM in series production. It included analyzing the printability and mechanical properties of SABIC’s LNP THERMOCOMP AM reinforced compound, used by Local Motors, after being printed, reclaimed, ground and reprocessed into pellet form.
The study determined that material from post-production parts and scrap potentially can be reused in LFAM or other processes, such as injection molding or extrusion, at amounts up to 100%. Insights and data from the study can help identify a feasible path to circularity and an extended lifecycle for materials used in AM, according to Walter Thompson, senior applications development engineer at SABIC.
One of the challenges of reusing LFAM materials is potential degradation from multiple heat cycles (grinding, re-pelletizing, re-compounding, etc.). Each step adds to the cumulative heat history, which tends to break down the polymer chains and reduce fiber length and can affect performance.
“As adoption of large-format additive manufacturing accelerates, it is essential to find sustainable alternatives to landfilling large, printed parts,” Thompson stated. He said the study with Local Motors “showed great potential for reusing these materials and marks a first step in supporting reuse within the value chain.” Added Johnny Scotello, Local Motors’ director of technical product, “Bringing value to scrap or end-of-life parts is a difficult challenge, but the results of this study point to a bright future for sustainable, circular products.”
Ryan Gehm and Steven Macauley contributed to this article.