Marginal Column

The great press review

For nearly 60 years now, Rexroth has been manufacturing components used in presses and shaping technology. Here is a historical rundown of the major developments.

 
Photos | Bosch Rexroth

Left: Control block for a press boasting about 13 tons of forging mass. Right: Standing next to the largest filler valve for extrusion presses, an employee holds the smallest valve in his hand.

It has been true from the very beginning: presses and Rexroth components make a perfect pair. Since the 1950s, the company has supported an ever-widening circle of customers in numerous projects in this field. Growth was spurred by the booming automotive industry which, at the same time, imposed the highest demands in terms of reliability, performance and component interchangeability. To satisfy those expectations, Rexroth engineers recognized in the early 1960s how important it was to obtain certification from the major car manufacturers for their technical solutions, which were becoming ever more refined. Success – in both domestic and international business – came in 1969.

 
Photo | Bosch Rexroth AG

Today's size 500 filler valve for hydraulic presses, achieving throughput rates of up to 90,000 liters per minute

In the years that followed, Rexroth advanced from being a supplier of parts to an all-around vendor of press drives. Special innovations, including new filler valves and control blocks, complemented the line. By the mid-1970s, Rexroth drives were found in diamond presses, giant scrap shears, and conventional forge presses. New accident prevention regulations went into force at the end of the 1970s and beginning of the 1980s. Machine owners and operators profited doubly from this ‒ since the control blocks installed as standard equipment already satisfied these regulations. There was no need to install or become familiar with new equipment.

 

With ongoing development of press and shaping technologies, precision joined forces with performance and safety on development engineers’ radar screens. Once again the automotive industry was a prime mover here since, in the 1980s, it began incorporating more and more body parts made from glass fiber reinforced plastics. Multi-layer components like this require exact synchronization and extremely accurate positioning. CNC axis controls built by Rexroth enabled the positions of two or more axes to be regulated. Developing a hydroforming press in the 1990s represented a significant breakthrough in press technology, and Rexroth supplied components, pressure intensifiers, and the controls. This technology “inflates” tubular blanks by applying liquid under intense pressure, expanding the blanks into the desired shape.

Due to the growing significance of energy efficiency, many manufacturers and users have recently attempted to replace hydraulic drive concepts with completely electric designs. The Rexroth engineers feel that both solutions offer great potential. Properly combined, they could satisfy requirements for both power density and energy efficiency. In 2012 the engineers presented both electro-hydraulic press designs and hybrid solutions – pointing the way toward the future of shaping technology.