Micro composite parts for medical ventilators

Especially in times of the corona pandemic and a weakening of the global economy, it is particularly important to us to be able to supply our long-standing customer, Asco Numatics company, with an urgent delivery of more than a hundred thousand of tiny piston valves. In the beginning, deliveries went exclusively to Ölbronn-Dürrn, but now Emerson plants in China and the USA are supplied with these precision seals, too.

These rubber-metal parts are installed as seals in valve blocks, which are then used to control the air volume in medical ventilators from a world market leader.

The rubber to metal bonded part has a diameter of 7.5 mm and is 3 mm high. With a rubber weight of just 0.07 g and tolerances in the hundredth of a millimetre and a surface roughness of Ra 0.4, this control piston requires in addition to a complex, process-reliable vulcanization not only an absolutely flat sealing area, but also many years of experience in the final inspection during the assessment of the sealing surfaces.


Whether sealing pistons or plungers, even with diameters of only 4 mm and heights of 1 mm with tolerances of + – 0.025 mm, HOFFMANN is also a competent and reliable partner for other valve suppliers of medical ventilators and medical control devices.

This is how the two managing directors, Dr. Andreas Hoffmann and Jochen Kugler, agree: “Especially in difficult times, it has become clear that specializing in the production of micro-bonded parts made of rubber, plastic and metal has proven its valve for the progressive miniaturization in all industrial sectors, as well as holding on to the Kirchheim production facility.