Marginal Column

Quality management: On the test stand

Quality has always played a decisive role at Bosch Rexroth. Test methods, however, have changed radically over the years and have become increasingly refined.

Quality management: on the test stand

Left: A hydraulic test bed in 1965. Right: Current test technology.

“Just imagine that somebody testing one of my products found that I had somehow supplied something shoddy. That thought was unbearable!” Robert Bosch’s statement back in 1919 is just as valid at Bosch Rexroth today.

When he wrote this, quality testing capabilities at smaller companies like iron-casting specialists Rexroth were still in their infancy. A product’s quality was determined primarily by the number of rejects. This changed when, in 1942, the company set up its own laboratory, where engineers were able to test both the development and the production of castings. The result: a substantial increase in product quality and a huge advance in development work.

The first test beds for functions

Some 60 years ago, that was the ideal situation for launching the production of hydraulic components, inspected for the first time in a hydraulics test lab designed and built by technicians. From then on, the development of new products and manufacturing processes went hand in hand with test engineering.

Especially after the end of the 1960s, the importance of quality testing grew when assembly lines were introduced. Quality inspection was integrated into production lines and the result was uniform high quality in every Rexroth product leaving the company. The more complex the products became, the more elaborate the test procedures. Checking to see that product specifications were being fulfilled became ever more complicated over the years – since the demands on testing technology quickly rose, and ever shorter testing cycles had to be realized.

Saying goodbye to analog

Pocket calculators, diagrams and tables – previously the designer’s most important utensils – soon proved to be not good enough. Computer technology opened up new opportunities. The arrival of digitalization meant that more complex product characteristics could be tested very quickly on computerized test beds. And there were also great advances in simulation technology. It was now possible to perform elaborate – but virtual – test procedures right from the early stages of product development.

As an example, at the beginning of the 1990s Rexroth developed a software package called HYSIS. This made it possible to simulate hydraulic drives assembled from valves, pumps, cylinders and actuators. Experience in both applications and test engineering was accumulated over the years. The company used this not only to develop its own products, but also to design innovative test bed technology in support of quality assurance.

Quality in seconds, all around the world

Since the beginning of 2004, Bosch Rexroth has pooled the development of its QM test technology at a dedicated center of competence. This has led to a test engineering network within the development and manufacturing matrix that now encompasses the world. Test procedures have also changed over time.

Since every second of machine running time impacts cost calculations, engineers have to develop ever more refined test methods to synchronize with the accelerated production processes used at every manufacturing location worldwide. This shows that product quality continues to be at the top of Bosch Rexroth’s list of priorities.