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Plastic Laser Sintering Helps Anubis Go With The Flow (Meter)

If you’re rolling out an industrial product and you want to manufacture it in the most efficient, cost-effective way possible, you may want to touch base with someone who has done exactly that time and again.

If you’re rolling out an industrial product and you want to manufacture it in the most efficient, cost-effective way possible, you may want to touch base with someone who has done exactly that time and again — Anubis Manufacturing Consultants Corp., Mississauga, Ontario, Canada. The company provides engineering services, equipment development and manufacturing for the pharmaceutical, chemical, consumer goods, and food and beverage industries.

“We’ve worked extensively in all these areas,” says Tharwat Fouad, owner of Anubis, “and we’re equally comfortable with projects that are highly specified or just an initial scope definition.” The company has particularly strong experience with powder handling equipment, sensors, and control instruments.

Recently, Anubis developed, patented, and commercialized a mass flow meter for particulates. Called the ARBOmeter, the device can operate either as a strictly volumetric device or, with the addition of a hopper and tray, a meter that can measure variable bulk density of materials. The ARBOmeter is easy and inexpensive to install on existing product lines, where it can be mounted without touching the product. The device is primarily used in the mining, plastics, recycling and food processing industries, and it can measure flow of everything from pellets to powder to potato chips.

Inside the meter’s stainless steel enclosure are a number of delicate electronic components, several of which require a framework that reduces vibration and keeps it in place. The individual frames need to hold each part firmly and accurately at a fixed angle. They also need to allow for easy, tool-free installation and removal. Components to be supported include two cameras and an LED light that have different shapes and require unique frames. “Given the challenges involved in making the frames, using additive manufacturing to make them seemed like a good idea,” Tharwat says.

Anubis offers a new additive manufacturing (AM) division for rapid prototyping and small production runs of end-use components. This production facility, which takes advantage of Anubis’ long-standing expertise in product development and prototyping, includes a FORMIGA P 100 plastic laser-sintering system from EOS of North America, Inc., Novi, Michigan.

Because of prior experience with EOS technology and materials, Anubis selected laser sintering as the process to make seven of the frameworks, including those for the cameras and LED light. There were several reasons for the choice: frame complexity (incorporating such features as built-in hinges and quick-release snap fits), small production runs and—most important—continuing evolution of the frame designs.

“Several of the plastic parts went through extensive redesign,” Tharwat says, “and we chose to revise the flow meter at least 15 times.” With so many changes, traditional plastics processes such as molding would be far too costly and would slow down product development. By contrast, using laser-sintered nylon (PA 2200, a Nylon 12 material), it was possible to manufacture the frames inexpensively and produce new versions overnight. The ability to make multiple revisions within tight turnaround times allowed Anubis to create optimal frames for each component.

Laser sintering’s potential for innovation and design freedom also prompted Anubis to consider an additional functionality for the frames: integrated cooling channels.

A cool alternative

The ARBOmeter employs an internal CPU that gives off heat. To protect electronic components, the temperature inside the stainless steel enclosure should not exceed 42o C/108o F. “We needed to explore a cooling system of some kind,” Tharwat says.

That presented a challenge. Standard practice might be to cut a hole in the enclosure and mount a fan. But in this instance, the device is IP 65 rated, so neither dust nor water can enter the enclosure—and that means no holes at all. Any cooling system would need to be internal. “We searched extensively and consulted electrical manufacturers,” Tharwat says, “but we didn’t find an inexpensive way to cool an enclosure and keep the IP rating we wanted.”

At this point, Anubis considered an intriguing possibility: Since the plastic laser-sintering system can create nearly any shape, it could incorporate channels inside the nylon frames so that air could flow through to cool the electrical parts. A thin layer of nylon isolating the components from the channels would ensure that the meter could still earn its IP rating.

Designing the cooling channels involved a number of considerations and revisions. Engineers calculated the volume of air flow needed to remove the heat and the size of the air conduit to carry that volume. Adding an impeller provided additional forced-air. By making the channels longer and narrower, air velocity accelerated even more. Taking advantage of the geometric complexity possible with laser sintering, the designers added fins and baffles to maximize heat transference. With each new modification, they quickly laser sintered and thermodynamically lab tested the part. “Being able to explore multiple iterations inexpensively was vital to this aspect of the project,” Tharwat says.

Although time constraints prevented Anubis from finalizing the cooling channel design on the ARBOmeter (the company has implemented a vortex cooling system instead), they are currently considering such a feature for several other applications.

Production and predictions

Meanwhile, the ARBOmeter has gone into full production and is being distributed initially by  ARBO Engineering, Inc., a supplier of volumetric and gravimetric feed systems for materials. Anubis will subsequently market it directly under the name Anubometer.

The meter’s laser-sintered frames are built in batches of four nested sets, seven to a set, over about twenty hours. Each part is made of 100-micron layers, one on top of the other. “The quality, repeatability, and durability of the parts are very satisfactory,” Tharwat says. “Laser sintering is uniquely suited to our needs on this project.” Anubis has minimized the frames to optimize set sizes and plans to run five sets at once in the FORMIGA P 100. The company expects to make between 100 and 200 ARBOmeters in 2013.

Anubis’ experience with plastic laser sintering and other AM processes has given them a broader understanding of the future role of the technology. “I believe that AM will close the competitive gap between larger corporations and small businesses, or even individual inventors, for bringing new products to market,” Tharwat says. “It will have a major impact on speed to market and will provide more manufacturing choices to end users. I don’t think it will eliminate traditional manufacturing—at least in the foreseeable future. But for low-volume applications, it is filling a valuable niche in which it is more cost-effective, and offers greater design freedom, than traditional processes.”