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Just another CNC: Renishaw tackles production printing

Kip Hanson
By Kip Hanson Contributing Editor, SME Media

A conversation with Contributing Editor Kip Hanson

Stephen, please describe the key drivers behind the development of the quad-laser RenAM 500Q, which you rolled out in October 2017.

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Stephen Anderson, AM business manager for the United States at Renishaw Inc.

The primary driver was the need for a metal 3D printer suitable for higher production levels. That means getting the build rates as high as possible while bringing the cost per part down. So we decided to put four 500-watt lasers into an existing 250 x 250 x 350-mm machine. Where some of our competitors have leveraged multiple lasers to accommodate bigger build chambers, our goal is to deliver maximum throughput and part quality for smaller workpieces. Doing so, however, required some significant technology advancements, including a chiller to cool the optical system, a servo-powered elevator with an optical encoder, a kinematic recoater, a patented vacuum preparation system, and more.

What should users know about a four-laser machine in terms of build strategy and suitable applications?

Having four lasers provides great flexibility. If you’re building a large workpiece, then you can bring all four lasers to bear on that one part. Specific lasers might be responsible for the bulky internal geometry, for instance, while others trace the outside of the part. Alternatively, if the build chamber is filled with a number of small components, you can assign an individual laser to each. We also have the ability to fire the lasers in continuous wave mode, which is how most systems work, or modulated wave mode, which allows you to turn the laser on and off very quickly. This enables you to do things like stitch individual melt pools together, or work on very fine details, such as thin walls and other delicate structures like complex lattices. Either way, you have full control over the build strategy.

Laser alignment is critical in any metal AM environment. How do you assure that four lasers are kept perfectly aligned?

That’s one of the reasons we build our own optical drive unit. Unlike other multi-laser printers, where each laser has a separate optical bank or optical scanning module, we bring all of the optics into a single unit. As the system expands and contracts due to thermal effects, it does so equally across all four optical trains simultaneously, making it much easier to ensure that each laser is aligned correctly. Further, we give customers the option of fitting the machine with our in-situ process monitoring system. This plugs directly into the optical drive unit and provides valuable information that can be used to keep the lasers working in perfect tandem. So despite the greater complexity of a four-laser system, we feel the RenAM 500Q gives customers a pretty good handle on laser alignment.

Renishaw’s touting the RenAM 500Q’s improved gas management capabilities. Why is this a big deal? Can you quantify any quality improvements?

Gas management is a complicated topic but is fundamentally about keeping the build chamber free of the nano-particulates generated during laser-based additive manufacturing. Doing so means less condensate on the optical window and an atmosphere that won’t interfere with the laser, decreasing the amount of power delivered to the workpiece. Positive gas flow also aids in the reduction of what is essentially weld spatter, which can become encapsulated and caught inside the build, potentially creating a crack origination point. Simply put, the cleaner the atmosphere, the higher the build quality.

You used conformal cooling channels in the galvo mount. Were they additively manufactured? Has this development improved the build process, or reduced maintenance, or…?

Renishaw has steered away from the individual optic trains used by other machine builders in favor of a compact, single-piece aluminum unit. And because we designed a proprietary optical system and then built it on our 3D printers, we were able to incorporate conformal cooling channels into the unit and then couple it with a chiller system. This approach dramatically increases its thermal efficiency, in turn improving beam stability, build speed, and part quality.

Do your recent success stories with Cobra Aero, Domin Fluid Power, Knust Godwin and the Brunel University London race team represent metal AM’s evolution into a mainstream, production-ready manufacturing process?

Yes. Many of our customers are multi-machine users, and they are producing components for their customers in production volume. That said, different industries are adopting this technology at different rates. Aerospace has adopted metal AM as a mainstream process. They’re producing thousands of parts per year. A similar situation exists for oil and gas, and to a lesser extent, with high-performance vehicles. And even though metal 3D printing is not yet fast enough for the consumer auto industry, carmakers are using it for tooling and fixtures, just as moldmakers are seeing huge benefits from additively-manufactured molds and mold inserts equipped with conformal cooling channels.

What notable developments or trends in the AM industry should shops be aware of?

As metal 3D printing becomes more mainstream, process validation and monitoring will become increasingly critical. This is particularly true for manufacturers and service bureaus that have printers in multiple facilities. It’s only through robust process monitoring and strict adherence to standards that manufacturers will be able to assure their customers that the 500th part in a production run is identical to the first one, and that the parts you build next year will be identical to those built today, regardless of the printer used or the facility it came from. Achieving this will require a “digital fingerprint” that carries with it a record of the build process and documents the build parameters, the equipment status, the raw materials, gases and a host of other variables that can affect the build process.

What’s the one piece of advice you can give to a shop that’s considering a move into metal AM?

If you can economically make whatever it is you want to make using conventional manufacturing methods, then do so. Too many people still think that, because AM is inherently less wasteful, it will save them money. In some cases, that’s true, but it’s more important to consider the value you’re imparting into the final product. If you can redesign the part to take advantage of all that AM has to offer, then it might make sense to take that journey, but only after you’ve thoroughly explored all the options. It’s a big step. Be sure to consider the ROI, prepare yourself for a long learning curve, and determine well in advance how additive will help your organization grow.

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A RenAM 500Q installation at Sandvik in Sweden

Northwestern University researchers develop futuristic 3D printer

Called HARP (high-area rapid printing), the new technology enables record-breaking throughput, manufacturing parts the size of an adult human in just a couple of hours. “3D printing is conceptually powerful but has been limited practically,” said Northwestern’s Chad A. Mirkin, who led the product’s development. “If we could print fast without limitations on materials and size, we could revolutionize manufacturing. HARP is poised to do that.”

The prototype HARP is 13-feet tall, has a 2.5 square-foot print bed, and can print at a vertical build rate of roughly half a yard per hour. It uses a novel, patent-pending version of stereolithography based on “high-resolution light-patterning ultraviolet light” to cure photoreactive resin, converting the liquid into solid objects. Because the material is continuously cured, however, HARP parts are said to be more robust and of higher surface quality than the laminated, “stair-stepped” structures common with other 3D-printing technologies.

The process also eliminates the extensive post-processing common to 3D-printed parts, further reducing costs. The result is a commercially viable route to the manufacturing of consumer goods. “When you can print fast and large, it changes the way we think about manufacturing,” Mirkin said. “With HARP, you can build anything you want without molds and without a warehouse full of parts. You can print anything you can imagine on-demand.”

CRP technology reverse engineers a broken component

Modern design and manufacturing technologies are suitable for a variety of applications, including the reproduction of broken or worn components when replacement parts are difficult to obtain or no longer available. Situations like these are becoming more frequent, and delays in finding spare parts can compromise productivity, resulting in lost time and money. Fortunately, technologies like laser scanning, advanced CAD software and 3D printing help to avoid all this, making the reproduction of even hopelessly obsolete parts possible.  

Such was the case recently when engineers at CRP Technology in Italy were tasked with reconstruction of a T-shaped linear actuator bracket for a large electro-mechanical blind. The team started by gluing the pieces of the broken bracket together and laser scanning it to produce a three-dimensional CAD model of the desired workpiece. Selective laser sintering was then used to 3D-print the replacement part from carbon-fiber-reinforced “Windform SP” composite material.

“The use of cutting-edge technologies has allowed the reconstruction and implementation of the component in a short time,” the company said in prepared remarks. “The overall manufacturing, from the reverse engineering phase to the construction via 3D-printing, took place in just a few days, after which correct functioning of the blind was restored.”

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On the left, the broken T-shaped attachment bracket for industrial blinds. On the right, the replacement part created via reverse engineering and selective laser sintering technology.

3D Systems makes orthopedic surgery more personalized

Additive manufacturing pioneer 3D Systems recently announced that the Food and Drug Administration (FDA) provided 510(k) clearance to its VSP Orthopedics solution, enabling surgeons to obtain a clear 3D visualization of a patient’s anatomy and develop a personalized surgical plan before entering the operating room.

“Throughout the years, the power and innovation of our VSP solutions have been demonstrated through improved patient outcomes in a variety of surgical specialties,” said Radhika Krishnan, senior VP, software & healthcare at 3D Systems. “Our 3D printing technologies, combined with the renowned expertise of our biomedical engineers and in collaboration with surgeons, can have a positive impact on a patient’s life.”

3YourMind: Moving toward distributed manufacturing

Industrial AM solutions provider 3YourMind is launching a Digital AM Inventory module for print-ready part files and production data, allowing organizations to move into production with a single mouse click. This saves significant costs compared with a physical component warehouse and is an important step toward distributed manufacturing.

The firm worked closely for longer than five years with Volkswagen, GKN, EOS, Continental, and other early AM adopters to develop the new module, it said in prepared remarks. That module’s features include centralized AM file management, storage of part specifications and production requirements, greater visibility of 3D model versioning and simplified repeat ordering through saved material and technology selections.

The AM Inventory module keeps the final production data in a single, validated system, which helps to ensure parts are produced the same way every time. Spare parts management is made easier, while inventory and logistics costs are reduced. Similarly, tooling lead-times can be dramatically shortened through the use of 3D-printed molds, jigs and fixtures, all of which are supported by the new module. 

Tooling provider Kennametal goes additive

Kennametal Inc. announced its move into the 3D-printing materials and production market with the formation of Kennametal Additive Manufacturing, part of its Infrastructure segment. The new business unit, which is already shipping production parts to customers, leverages the company’s longstanding expertise in materials science to supply high-performance metal additive powders and fully finished 3D-printed parts for wear, erosion, corrosion and high-temperature applications.

“Kennametal Additive Manufacturing combines our recognized expertise in wear materials, such as tungsten carbide and Kennametal Stellite, with the advantages of 3D-printing,” said Ron Port, VP of Kennametal Inc. and president of the infrastructure business segment. “We are focused on high-growth potential additive solutions, and this new business unit is advancing both what we make and how we make it so that we can produce better parts, faster and more efficiently, for our customers.”

Kennametal has used 3D printing for some time to manufacture prototype components and cutting tools. Kennametal Additive Manufacturing builds on these capabilities to offer comprehensive 3D-printing solutions, from raw material to finished part. For example, the company’s gas atomization powder production capability supplies cobalt, nickel, and iron powders optimized for specific additive manufacturing processes, while its research and development, pilot production, and prototyping center in Latrobe, Pennsylvania utilizes laser powder bed and binder jet printing technologies to produce fully finished components.

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Kennametal Additive Manufacturing is focused on faster development and production of wear-resistant components, such as this prototype solid carbide drill head for oil and gas applications.

Desktop Metal unveils continuous fiber 3D printing

The company known for desktop printing of end-use metal parts has introduced Fiber, a 3D printer able to fabricate high-resolution parts from the industrial grade continuous fiber composite materials used in automated fiber placement (AFP) processes. “Fiber printers combine the material properties of high-performance AFP materials with the affordability and speed of a desktop 3D printer,” Desktop Metal CEO Ric Fulop said.

The new process, called “micro automated fiber replacement” (μAFP), allows users to print parts with a superior level of strength and stiffness using a broad range of materials, parts that traditionally required million-dollar AFP systems. Key applications include tooling like robotic end effectors, soft jaws for CNC lathes and laser etching fixtures for medical tools, as well as end-use parts for the automotive, electronics and consumer goods markets—and components where light-weighting is critical for performance: wheelchairs, for example, and sports racing equipment.

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The Desktop Metal Fiber printer is the first 3D printer with AFP continuous carbon fiber reinforcement, delivering industrial fiber performance on the desktop.

“After more than three decades of development, AM has finally reached a tipping point,” said David Hauber, engineering manager of Trelleborg Sealing Solutions Albany Inc. “With Desktop Metal’s new AM technology, engineers will be able to print industrial quality, continuous fiber reinforced composite structures with high fiber volumes and high Z-axis strength. These benefits are combined with high resolution printing and beautiful surface finishes that give users flexibility in how they can cost-effectively design and manufacture high performance composite structures.”

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