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06. July 2017

USA - Additive manufacturing aims for production-scale

USA - Additive manufacturing aims for production-scale

Matt Pulzer reports from a buzzing additive manufacturing conference in Pittsburgh, where a major announcement from Stratasys heralded additive technology’s move into continuous manufacturing.

The scalable nature of the Stratasys Continuous Build 3D Demonstrator allows it to be easily expanded according to production requirements – image courtesy of Stratasys.

This year’s RAPID + TCT annual conference was held in Pittsburgh, Pennsylvania. For such a young industry, RAPID has quickly grown into a vast exhibition with everything you could possibly want or need in the world of additive manufacturing – from small desktop plastic printers to the latest and largest metal fabrication systems.

In a sector awash with new ideas, technology and materials, it’s hard to boil down a year’s progress into a few pages, but here are four companies and their products that neatly represent the progress being made, as additive continues to march from a niche research and one-off production tool to a mainstream manufacturing system.

Stratasys production line

3D printing and additive manufacturing company Stratasys has taken a significant step into low-volume, continuous production using additive technology. At RAPID, it unveiled a new product under development – the Stratasys Continuous Build 3D Demonstrator.

The new platform is a scalable array of modular units, each containing a standalone 3D print cell. Individual cells work in parallel and are driven by a central, cloud-based architecture. The demonstrator produces parts in a continuous stream, with only minor operator intervention, automatically ejecting completed parts and commencing new ones.

Each 3D print cell can produce a different job to help enable mass customisation projects, meaning the array can produce multiple one-offs or thousands of the same item.

Additional cells can be added at any time to the scalable platform to increase production capacity as demand requires. Automatic queue management, load balancing and architecture redundancy help promote optimal throughput as jobs are automatically routed to available print cells.

If a single print cell fails, the job will be automatically rerouted to the next available cell. The cloudbased nature of the 3D Demonstrator’s control means that jobs can easily be placed in multiple physical locations.

Target applications include all production environments that can benefit from zero-tooling production and from a zero inventory supply chain. Printed parts are ejected on a substrate of easily peeled film that is roll fed and cut before landing in a front-loaded hopper.

Stratasys has been working with a wide variety of customers, including designers, educators and manufacturers to develop the 3D Demonstrator. At the Savannah College of Art and Design, all students now have 24/7 access to Stratasys’ 3D printing services.

Students represent a particularly demanding test bed since they invariably need one-offs or small quantities, often at unpredictable times and are therefore well placed to thoroughly test the cloud-based scheduling technology.

The 3D Demonstrator has also been put through its paces at InTech Industries, a supplier of rapid prototyping/ additive manufacturing, tooling services and injection moulding. The array enabled InTech to offer a bridgeto-production solution for their OEM customers.

The automated workflow enabled the company to offer same-day or next-day delivery of quantities of identical or mixed parts that might otherwise require the use of expensive and long-lead-time injection moulding tooling.

At the launch, Scott Crump, Stratasys co-founder, chief innovation officer, and inventor of fused deposition modelling (FDM) additive manufacturing technology, commented, “The Stratasys Continuous Build 3D Demonstrator is an important milestone in the company’s long-term vision to make additive manufacturing a viable solution for volume production environments.”

Commercial product availability has not yet been announced by Stratasys.

HP Jet Fusion

Hewlett Packard’s Jet Fusion 3D Printing Solution was announced at last year’s RAPID in Orlando, Florida. This year, it was on display and busily printing precision parts, voxel by voxel (a volumetric pixel). HP’s offering is a large two-part machine, consisting of a printer and a post-processing station, available from $155,000. The platform uses HP’s 3D PA12 material, a strong, multi-purpose thermoplastic designed to optimise cost and part quality thanks to its reusability.

A wider family of thermoplastics will follow in the future, including glass beads and materials with flame retardant properties, as well as elastomers.

Future plans aim to include a larger range of materials and the ability to print materials with embedded sensors and other intelligence to support the Internet of Things. Plus, HP aims to offer printed parts with embedded traces to support smarter supply chains.

Fabrisonic has developed a ultrasound bonding process for sheet metal that offers a wide range of metal-on-metal options without using high tempartures – image courtesy of Fabrisonic.

Unsurprisingly, an additive exhibition like RAPID is dominated by conventional thermal/plastic extrusion technologies, but there were novel approaches. Welding engineer Cameron Benedict from Fabrisonic talked me through their unique take on additive.

“We use ultrasound (20kHz) to vibrate thin sheets of metal that are pressed together to create a solid-state bond. A key advantage of our technology is that it requires no heating, so the low temperatures involved do not compromise or alter the properties of the sheet metals used.

Even more important, the low temperature process allows wires, sensors and electronic controls to be embedded in solid metal parts.”

The process allows dissimilar metals to be welded together and Fabrisonic offers a wide range of metal options, including aluminium, copper, titanium, tungsten, invar, tantalum, molybdenum and europium.

The two-dimensional nature of the process means that pre-cut sheets can be layered to include three-dimensional chambers and channels, allowing fluid paths and heat exchangers to be built. This approach enables pressure vessels with burst pressures of over 6000PSI (greater than 400 bar) to be additively built.

Desktop Metal

Moving on to another metal system, I spoke to Rick Chin, VP of software development at Desktop Metal (DM). The company is gearing up to launch two printers – a studio machine for prototyping and low-count production, and a high-capacity machine for custom-manufactured parts.

Desktop Metal’s platform uses a choice of wax/plastic-bound metals fed into the system as rods – image courtesy of Desktop Metal.

The studio system launches in September and will initially work with seven (quickly growing to 30) metals. Users can choose between a variety of chrome-moly, stainless and tool steels, copper, Inconel and low-expansion kovar.

“The underlying technology is MIM (metal-injection moulding),” Rick explained, “an extrusion/sintering process using a metal powder mixed with wax/plastic. Metals are inserted as rod cartridges (60% metal by volume) and then printed using a thermal extruder to create beads.

“A product is then built up and a second printer adds a ceramic-based support material for overhanging/cantilevered parts. Next, a ‘debinder’ removes the wax in which the metal is suspended and the part then moves to the furnace, which operates with a combination of conventional thermal and microwave heating.

In the furnace the ceramic support material is not sintered, so it easily crumbles away post-fabrication.” Rick told me that this is a key advantage as many other systems use metal to provide supports, which has to be cut away in a lengthy, fiddly and inconvenient process.

“The software that generates the printed part also provides information for the furnace,” Rick continued, “so that sintering is bespoke to a particular component. The design process creates a part-specific temperature ramp-up/down profile and also takes account of shrinkage in the furnace so that parts scale to the correct size. In other words, users do not need to be sintering experts – the whole furnace process is automated.”

DM’s three-box process – printer, debinder and furnace – will cost $120,000 when launched in September (a standalone printer is $50,000).

Source: themanufacturer.com

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