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A path to coating without PFAS

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For more than 20 years the Brüning Flexible Finishes company has been using Rotamat equipment for coating small, mass-produced parts made from elastomers and rubber. During this time the company could significantly increase its market share. A major challenge for the future is the transformation to coating materials that no longer contain PFAS.

From pill turning to environmentally friendly coating of high-tech components

For more than 40 years Brüning Technical Coatings und Brüning Flexible Finishes have specialized in coating components for customers from a broad range of different industries. These include machinery manufacturers, the automobile industry and the heating and cooling sector. The two companies also work with manufacturers of photovoltaic systems and electric vehicles. Demand in these areas has been growing rapidly.

More than 20 years ago the founder of the company, Fred Brüning, started using rotary drums for coating large volumes of parts made from rubber and elastomers. He conducted his first trials in a film coater that had initially been developed for the food and pharmaceutical industry. In view of the rapidly growing demand and stricter demands for functionality and quality of the coatings it became very quickly clear that the company needed machines that allowed safe and high-quality processing of industrial functional lacquers.

Success through a long-standing partnership

In search of a suitable system the company came across the Rotamat coaters from Walther Trowal. In its purchasing decision for the first Rotamat system the company considered the excellent reputation Walther Trowal enjoyed in the market and the relatively short distance of 150 km to the Trowal location in Haan. The first machine, purchased 20 years ago, was a Rotamat R 70. Because of growing demand and the excellent experience with the Trowal system, later on a R 90C model was purchased. This helped to double the coating capacity. In 2022 an additional R 90C Rotamat coater was added.

The Rotamat R 90C was commissioned in the year 2022.

Prepared for future challenges

With its three coaters Brüning is able to apply functional lacquers on practically all kinds of substrate materials in any batch size, irrespective of how challenging the coating task might be. The coating materials are PTFE lacquers such as Xylan, PFAS-free silicone lacquers or solvent-free special anti-friction lacquers. Moreover, Brüning also uses FDA approved lacquers with equipment components used in the food and medical industry. The largest product group are O- or X-rings made from elastomers and rubber.

O-rings represent the largest share of the components that must be coated.

Interchangeable drums bring flexibility to production

The three Rotamat coaters provide the company with the necessary flexibility to process large work piece volumes as well as small component batches. In this respect the possibility to quickly exchange different drum sizes is particularly valuable: Even the larger machines can be operated with smaller drums. This minimizes redundancies and significantly reduces lead times.

Minimal staff requirements

The Trowal machines are so reliable and sturdy that even the first machine, purchased more than 20 years ago, is still fully operational day in day out. But looking at the three Rotamat systems used at Brüning, it becomes clear that during this 20-year period Walther Trowal has continuously improved its Rotamat coating technology. The new machines contain more sensors, and the process controls have become more precise. One example for improved process controls in the new machines is the precise dosing of the lacquer: The operator is immediately informed, when a lacquer nozzle is plugged. Furthermore, the lacquer quantity passing through the nozzles can be precisely documented. Since most customers must certify how much lacquer was applied and must confirm the lacquer thickness on the work pieces, this is an extremely valuable tool.

Inspection of the surface of an O-ring after the coating operation.

Over time Walther Trowal has also simplified the operation of the Rotamat coaters by making the controls more intuitive and facilitating the setting of the process parameters. Today one operator controls all three machines. Moreover, equipment faults can be diagnosed by remote trouble shooting through the internet.

Close contact pays off

While the purchase of the first machine was primarily influenced by the excellent reputation of Walther Trowal, over time the cooperation between the two companies became very close, certainly one reason for the success of Brüning in the field of coating. There is a continuous exchange of ideas by both sides. For new challenging coating applications Brüning staff and the experts at Walther Trowal conduct comprehensive processing trials in Haan. For maintenance and other service work Walther Trowal service engineers are available in Heteren within 24 hours.

New markets conquered

Looking back at the last 20 years it becomes obvious that Brüning always purchased the right machine at the right time. The three Rotamat coaters could not only handle the continuously growing demand of the existing customers, but they also allowed Brüning to enter completely new markets. This positive business development would not have been possible without the Rotamat technology.

Willem-Peter Brüning, Managing Director at Brüning Flexible Coatings B.V., inspects a coated O-ring.

Profitable for customers: Outsourcing the coating process

The three machines allow Brüning to offer a high-quality, flexible service with short lead times, which companies using a single coater in-house for coating their components cannot duplicate. This is complemented by the know-how of the employees, who are able to develop new, complicated coating applications and innovative solutions … for example special approvals and cost-efficient coating processes. Brüning also relieves customers from time-consuming, costly activities, for example, handling of hazardous chemicals, measures for occupational safety or the disposal of waste materials.

The future: PFAS-free

With its current coating equipment and know-how Brüning is well-positioned for the future: Already today the company is using high-quality PFAS-free lacquers. The main challenge for the next few years will be the complete switch to PFAS-free lacquers – a globally urgent issue. Contrary to decorative lacquers many functional coating materials still contain substances like polytetrafluoroethylene (PTFE) and solvents that must be replaced. Although these substances are not yet prohibited, there is a lot of public pressure for discarding them. But despite these challenges there is no doubt that Rotamat drum coating will be the dominant coating technology for small, mass-produced parts. 

About Brüning – The Coating Company

Fred Brüning, father of the current managing director Willem-Peter Brüning, founded the Brüning Technische Coatings B.V. more than 40 years ago. The core business of the company is still the coating of components made from metal, such as springs for automobiles, screws and nuts for petrochemical installations, busbars for batteries and other parts for various industrial sectors.

Later on the Brüning Flexible Finishes B.V. was added, specializing in coating of mass-produced small parts made from rubber and elastomers – primarily O- and X-rings. The company operates three Rotamat coaters  and various smaller and larger coating cabins and curing ovens.

At the two locations in Heteren, in the Dutch province Gelderland, the company employs 35 people.

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