Elmet rides cutting edge of LSR processing, tooling tech | Rubber News

ATLANTA—Since Elmet began in 1996, the Oftering, Austria-based supplier of dosing systems and multi-component molds for liquid silicone rubber components has adapted its technology as major markets have shifted.

Such tectonic shifts are occurring again, this time in the medical and electric vehicle spaces—where Elmet finds itself once again at the leading edge of LSR processing.

"Our key growth area has been in the automotive sector, specifically in e-mobility and hydrogen fuel cell applications," Bilal Rafiq, business development manager for the Americas at Elmet, told Rubber News.

Elmet and Rafiq were present in Anaheim, Calif., Feb. 6-7 at the MD&M West Show to showcase the firm's medical LSR processing services, also a burgeoning market with about 5-percent CAGR expected through 2027.

The shift to increasingly tight tolerances and wide spectrum of tooling variations required for LSR components can be daunting. Elmet embraces the challenges, especially as "automotive is about even with medical" in the company's market breakdown, Rafiq said.

"These applications demand specific requirements ... from the silicone selection with critical mechanical and chemical characteristics, as well as intricate part designs challenging our mold designing team," Rafiq said. "We have further innovated in this space and built the largest (in terms of size and weight) LSR cube mold ... that (includes) overmolding the thinnest and largest plastic film that we have seen in the market."

Elmet has about 200 employees today, with offices in Japan, China and North America.

Another of the company's North American offices is in Lansing, Mich., where it carries stock machines and spare parts to service customers in North, Central and South America.

Elmet's dosing systems and mold-making technologies can be integrated with most major injection molding machines.

"Arburg and R.D. Abbott (more inclined to research and education) both are our strategic partners, along with many other injection molding and material suppliers," Rafiq said. "We provide all the equipment that complements an injection molding machine—from the dosing system, molds, end-of-arm tooling and the peripheral components like dive nozzles, check rings and vacuum/cooling manifolds.

"With material suppliers, we do extensive collaboration efforts to work on specific customer applications as well as working to develop and improve materials to satisfy customer needs."

Rafiq has eight years of LSR experience, and at Elmet he has worn a number of engineering hats: as a project, process, tool design, quality and application engineer.

Elmet's technology specifically caters to LSR processing, though the company also works with high consistency rubber (HCR, or gum rubber) and high-temperature vulcanizates.

"We also have an extensive history in combining silicone with plastics, metals and other substrates in two-component or multi-component applications," Rafiq said. "We have worked on a few projects with TPEs in the past, but our focus is on silicone injection molding."

Elmet's dosing systems work on any liquid-based resin, including the standard LSR that comes in A and B components. A third stream can add a colorant or conductive property.

Uniquely, Elmet systems can support specific catalyzed silicones that require different ratios—like 60/40, or in some cases, 95/5.

"In principle, our systems can dose a wide variety of liquid resins that require mixing and preparing ... such as epoxy or other single- or two-component resins," Rafiq said.

Elmet can build high-volume, tiny molds; offer turnkey solutions with its strategic industry partners; and offer automation that integrates secondary processes like slitting, laser engraving, pad-printing and inspection.

And this goes for both LSR and HTV/HCR applications.

"All solutions are designed so that the parts are rework-free and do not require any deflashing operation," Rafiq said, adding that Elmet also provides "high quality and fully balanced" cold decks to other LSR mold makers.

"Our cold runner systems enable a highly precise cavity filling with no material waste, thanks to pinpoint feeding, leading to short cycle times while providing a reliable and stable process," he said. "Our cold decks are specified to our customers' requirements based on nozzle spacing, nozzle type (open gate, valve gate with stepper motors, or servo driven valve gate), and vacuum channels."

In addition, Elmet provides all of the training necessary for customers to maintain and operate the mold "at a high level for many years as some customers report over 10 years of continuous usage and still operating at peak performance," Rafiq said.

Elmet has seen a renaissance in the last several years, as the supply line hurdles of the pandemic have waned and Elmet has been able to obtain the parts for its systems—from microchips for automation to raw materials, like silicone and HCR.

"I think we have seen the worst of the supply chain and inflation issues from our perspective, and the market has stabilized," Rafiq said.

"Certainly, the pandemic served as a data point. We have further refined our supply chain strategies to improve restock planning, safety stocks and purchasing power. We also rely on a high degree of in-house production, which makes us independent of external influences."

Besides the challenge of adapting to market shifts, new developments have been the norm at Elmet over the last two years.

The company recently opened a new facility in Oftering, doubling its production floor space there and dedicating another area to research and innovation.

The company in March 2022 appointed Harald Wallner as CEO. He brought an extensive background in plastics manufacturing from his time at Greiner, also in Austria.

The technical innovations continue at Elmet, as well, according to Rafiq.

"We will be unveiling a new dosing system during NPE 2024 (plastics show) in Orlando, Fla.," Rafiq said. "I am not able to share much information other than the fact that it is smaller than our existing systems."

And size matters in liquid injection molding.

Elmet has constructed very large molds that fit onto 1,000-ton presses, molds that possess intricate shutoff patterns and require precision dosing.

"The smallest mold we have built can fit in the palm of your hand and overmolds a polycarbonate ring that is 2 millimeters in diameter," Rafiq said. "We have applications that continue to push the boundaries of what is possible, and we take on these projects with excitement as our engineers feed off these projects to innovate in this space."

Large silicone components and molds demand critical designs in cooling and heating, minimizing cycle time and reducing the risk of damage during demolding.

For micromolding, Rafiq said challenges include control of filling, controlling mismatches and "reliably demolding and capturing the parts as they are manipulated easily by air and static charge."

"We have developed a fully electric servo-driven cold deck, the SMARTshot E, to drive the needle actuation and adjust while capturing the data of each shot," Rafiq said. "The fully electric needle actuation is performed by a brushless servo motor and guarantees an extremely fast (less than 0.1 seconds) and smooth needle movement."

Essentially, the servo motor combines high control quality with minimum heat generation.

"The perfect synchronization of the needle movements also ensures optimum process stability," Rafiq said. "The small size of the drive unit makes nozzle spacings of only 44 millimeters possible and enables the construction of compact molds for micromolding."

While micromolding typically is a province of the medical industry, the use of optical-grade LSR for parts in LED lighting fixtures in automotive has been established for more than a decade now, according to Elmet and Dow.

In an October 2022 white paper authored by engineers from the two companies, "Adaptive-Driving-Beam Headlights: A Collaborative Approach to Efficient Manufacturing of Complex Shapes," Elmet and Dow certified a "12-lightguide matrix lens design" using two specific types of Dow Silastic-brand silicones, both of which boast optical properties.

The benefits of optical silicone versus other traditional optical materials—like epoxy, acrylics, polycarbonate, glass or quartz—are numerous, Rafiq said.

Photo-thermal stability is better in optical silicones; high luminous transmittance and low chromatic dispersion traits are improved; and stability against sunlight and UV radiation is improved.

ADBs—or adaptive-driving-beam headlamps—have taken off in Asia and Europe.

"We have begun to see the demand for matrix headlight applications in the U.S. as the (National Highway Traffic Safety Administration) has allowed OEMs to include these in their vehicles ... and we have built several of these production cells for our European customers," Rafiq said. "These require specific molding concepts, due to the varying part thicknesses and very low viscosity of the optical clear silicones."

Essentially, ADBs turn the headlights as the driver turns the steering wheel. The headlights can adapt to curves, illuminating the roadway around the turn.

But they don't come cheap, and replacement costs can be high, which may be reflected in insurance premiums.

Adaptive headlights also tend not to be repairable if something goes wrong, being sealed units that need replacement if they develop a fault, or are damaged by a loose stone, for example.

According to the white paper, the principle of ADB headlights is based on dynamic and addressable control of multiple LED light sources.

"Each LED is aligned to a single lightguide of a multiple-lightguide silicone primary optic that projects the light beams on the road through a front secondary optic in the light engine," the paper states. "ADB headlight technology enables long-range visibility without causing glare, discomfort and distraction, improving safe driving at night."

It is Elmet and Dow's hope that the use of ADBs contribute to reducing the number of roadway collisions and an increase in automotive safety.

"Elmet addressed such challenges with innovative, high-precision mold fabrication technology," according to the paper. "The effective, collaborative approach of Dow and Elmet has proven to significantly advance the understanding of how optical silicone elastomer formulations and liquid injection molding processing are intimately related."

From Dow's side, both the Silastic MS-1002 and MS-5002 moldable silicones are optical LSRs that are now offered on the market.

Whether the end product is in the automotive or medical OE space, communication with a customer early in the design process is key, Rafiq said.

"Early on in a project, we want to be involved to support the design and development of the part as this is critical to ensure we can include key design for manufacturing features," he said. "This is especially important for medical applications, as once the materials and design are set after FDA approval, it takes a lot of resources to make changes."

Turnkey solutions—typically a partnership between a dosing and tooling company like Elmet and an injection molding machine manufacturer (and other partners)—can be an optimum way for a customer to have access to a full-service production cell.

"We spend a great amount of time discussing the needs of the customer and what will happen to the component afterward to ensure we add value to the component to save resources and production floor space," Rafiq said. "We are hard on ourselves to ensure we are delivering top quality molds and turnkeys."

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