World's most powerful die casting machine from Bühler with Roth hydraulic accumulator - precise piston stroke for reliable production

Uzwil (Switzerland)/Biedenkopf (Germany). With the Carat 840 and the Carat 920, Bühler from Uzwil is further expanding its range of die casting solutions. They are the most powerful machines of their kind in the world. The company is thus responding to the increasing demand from the automotive industry for machines to produce ever larger components. An important part of the new machines are the hydraulic accumulator systems from Roth Hydraulics in Biedenkopf. They enable high component quality and ensure reliable and energy-efficient casting forces for the machine.

Automobile manufacturers are breaking new ground in their production. New production processes with high clamping forces are required for the manufacture of large-format and complex aluminium components for car bodies, for example to produce front or rear underbodies for vehicles. The new Carat 840 and Carat 920 die casting machines from Bühler make such production solutions possible. The central component here is an extremely powerful and precise injection unit with uniform clamping force application. To reliably meet this requirement, Bühler decided to use a pressure accumulator system from Roth Hydraulics. It is the drive of the casting unit, which decisively generates the component quality and ensures a permanently reliable performance.

Powerful and dynamic casting unit
The demands on the accumulator system are many-sided: on the one hand, the new solutions require a larger amount of stored energy and, on the other hand, an extremely fast power development in order to ensure the necessary dynamics of the injection unit. The Carat 920 casting unit, for example, develops 2130 kilonewtons of dynamic casting force and 5340 kilonewtons of solidification pressure. The special challenge here is to enable around 1.5 metres of piston stroke within 100 milliseconds in the second phase of the casting process. The acceleration of the entire system including liquid aluminium is practically from zero. "The Carat 920 can inject more than 200 kilograms of liquid aluminium into a mould within milliseconds. In doing so, it holds the mould together with a force of 92000 kilonewtons. That's as if the entire Eiffel Tower, with its weight of around 9000 tonnes, was pressing on the mould," explains Michael Cinelli, Product Manager Bühler Die Casting. The Roth Hydraulics hydraulic accumulator manages this production task with ease and high precision. To achieve such solutions, the experts from Bühler and Roth Hydraulics have been cooperating for many years. Michael Cinelli emphasised: "The many years of cooperation in component development with Roth has always made it possible to quickly develop new solutions and further develop existing technology. The joint focus is always on the end customer and the required reliability of the components." The largest die casting machines in the Carat series are as big as a house. They are eight metres high and stand on a floor space of around 100 square metres. In addition, the Carat's two-platen technology features a patented and stiffness-optimised platen design for uniform clamping force application, ensuring minimal platen deflection and high dimensional accuracy of castings. In combination with Bühler's unique real-time controlled casting unit and DataView control, the Carat offers the highest casting dynamics and quality.



The die casting machine Carat 920 from Bühler is equipped with a hydraulic accumulator system from Roth Hydraulics.
(Photo: Bühler AG)

Highest productivity and environmentally friendly production
The enormous power density of hydro storage systems as well as the precise release of energy in the right quantity and at the required time in die casting production saves electrical energy and significantly reduces the required connection power. In addition, the use of recycled aluminium or aluminium obtained through renewable energies enables the potential of CO2-neutral production. As a component of the entire production chain, this improves the ecological footprint of the end product, in this case of the vehicle. Bühler's vision for the future of the die casting industry is 0 percent scrap, 40 percent less cycle time and 24/7 availability. The larger the castings, the greater the leverage for reducing production costs by reducing cycle time, scrap and increasing availability. Bühler is a pioneer with machines for the production of large die-cast parts and the world market leader in this segment. The Roth family company is also a world market leader in the segments of energy storage systems, composite technologies and surface heating and cooling systems. Frank Fuchs, Managing Director of Roth Hydraulics, explained: "Family-run companies pursue similar values and focus on personal customer relationships. We are pleased and proud that we have been cooperating with Bühler on this basis for many years. The use of our hydraulic accumulators in the new Carat range underpins our successful partnership." Roth Hydraulics offers energy-efficient hydraulic accumulator solutions for technologies where hydraulic energy needs to be stored or converted. The fluid technology components are not only used in die-casting machines, but also in energy and power plant technology, mobile hydraulics or in oil and gas technology. Roth Hydraulics is a traditional company in the industry with a history of almost 80 years - known under the previous company name "Bolenz & Schäfer". As a full-range supplier, Roth Hydraulics provides a complete technology range with piston, bladder and diaphragm accumulators as well as accumulator systems for a wide variety of applications. Know-how and experience in the development and production of piston accumulators make the company a true specialist. Roth storage systems are designed according to a modular principle. Depending on the requirements, the manufacturer implements customised and economical solutions, as in this case for the family-owned company Bühler. .

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