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From: 中国锻压协会

Applying just the right force – Schuler’s multiple-cylinder press ensures perfect material flow in the production of heat exchanger plates

Heat exchanger plates are highly versatile systems for transferring coldness or heat between fluids or gases. The process is used in the production of paints, paper and food as well as in the cooling systems of ship’s engines and for heat recovery in power stations. This wide variety also means that manufacturers of heat exchanger plates have to ensure the safety and efficiency of their equipment when warming or cooling completely different materials – from carbonated drinks to plastics and electrolytic baths. GEA PHE Systems is one of North America’s leading producers of heat exchanger plates. At its new facility in York, Pennsylvania, the company produces plates on a custom-designed hydraulic press supplied by Schuler.

The demands made on the short-stroke, multiple-cylinder press are particularly high in this technological field, as heat exchangers contain plates formed from a variety of materials – such as titanium, alloys or the rare metal tantalum. Fixed in a frame made of carbon steel or stainless steel, they provide a highly effective heat transfer surface for the fluids or gases flowing past. Precision is of utmost importance when producing such plates in various sizes and shapes. Jean-Pierre Castenetto, Production and Logistics Manager at GEA Ecoflex and GEA PHE Systems in North America, adds: “We also need a high degree of flexibility for the production of completely different heat exchanger plates. It is therefore important, for example, that the dies for the production of plates can be quickly exchanged in order to keep downtime to a minimum.”

Many small cylinders replace one large one

To meet these needs, Schuler developed a custom-built hydraulic press with a short-stroke, multiple-cylinder function, which can guarantee precise material flow and high quality at all times. In the case of heat exchanger plates, this means no wrinkles or defects in the final product. In order to reach its full press force, the system uses many smaller cylinders instead of one large one. The benefits: the individual cylinders can be grouped differently depending on the field of use. This means that the material is carefully monitored during the forming process. Areas in which material flow is not desired – due to the risk of fracture – can be left out. In other areas, the pressure force can be reduced in order to avoid wrinkling. “Small cylinders also need far less compression oil than a press with a large cylinder and a long stroke,” explains Oliver Beisel of Schuler Hydrap. “In turn, this leads to much shorter cycle times in the press and thus to higher output levels. It also reduces costs, as machine maintenance is much faster.”

Complete system delivered

The turnkey system which Schuler delivered to the USA comprises a decoiling station with slitting shear, a single-track shuttle as automatic feeder and a die change cart which can be equipped with three dies simultaneously. Dies can be changed in less than 30 minutes. The shuttle takes the formed plate out of the coining press and transports it to a stamping press, where the plates are given their final shape. An automatic transport device removes the plates from the line and stacks them on top of each other. The Schuler line enables the production of up to four plates per minute. Only one machine operator is required. “The system gives us the necessary flexibility to change jobs quickly and to produce a variety of different plates,” explains Jim Buffington, EcoWeld Production Manager at GEA PHE Systems.

Further uses feasible

The technology is not only suitable for complex applications, such as the production of heat exchanger plates. It is also ideally suited for the deep drawing of stainless steel, for example in the production of kitchen sinks. In this case, the system uses an active draw cushion and a multiple-cylinder plate, which takes on the function of an hydraulic cushion under the holding device. In the coining press, the multiple-cylinder plate merely transfers the press force. Due to the variety of possible uses, Oliver Beisel believes that presses with multiple-cylinder technology also have great market potential: “Using this technology generally makes sense whenever the demands of a product exceed the boundaries of conventional forming processes. It even makes complex forming processes easy to achieve.”