Perfect prototype measurement

Small but very capable components are in great demand in the motorvehicle industry. This doctrine of the designers leads to ever-tighter tolerances on vehicle components. And continues to throw down new challenges to quality management – also at the Robert Bosch Works, Immenstadt. The Metrology Team tackles its tasks in the prototyping department there using a highprecision Leitz Reference Xi.

Situated in the middle of the delightful Allgäu countryside, the Immenstadt factory complex produces anti-lock braking systems (ABS), electronic stability programmes (ESP), ignition coils and electronic sensors for driving safety and fuel injection systems on series production lines and as prototypes. With some of these systems, Immenstadt takes a step to the side from running the series production lines. Process development and the construction of special machines and prototypes help maintain and expand the company‘s essential know-how.

Innovation-led prototyping
„Our Prototyping Department is very specialised and yet very flexible,“ says Hubert Hueber, who is Group Manager of the Protoyping Department and responsible for Chassis Systems Control. „In our field of work we manufacture prototypes, such as concept, procurement and release samples of ABS and ESP systems, which have to be dimensionally accurate for our in-house development departments and for OEMs all around the world. The batches typically comprise 1 to 100 system units per order.“

Tight tolerances, accurate CMM
The call for enhanced functionality with fewer moving parts reverberates around the think tank at Immenstadt: as systems become smaller and more compact, the tolerances tighten to match. Therefore Bosch has opted for a high-precision 3D coordinate measuring machine (CMM): a Leitz Reference Xi from Hexagon Metrology with a maximum permissible error of indication (MPEE ) for longitudinal measurements of 1.2 + L/350 μm and a measurement range of 1000 x 700 x 600 mm. When measuring a length of 1 m for example, this CMM achieves an accuracy deviation as low as 4 microns.

A CMM is a source of information
The metrology technicians check samples taken at random from prototype production using the measuring machine in the climate controlled room. The majority of the test . . . . . .