Sankt Augustin, Germany - Dutch company Filtrair has been helped in its manufacture of high-tech air filters for industrial uses by PU know-how supplied through machinery maker Hennecke GmbH.
At Filtrair's Heerenveen, Netherlands, headquarters, "the focus has been on polyurethane for quite some time," for better stability, weight reduction and corrosion resistance, said a press release from Sankt-Augustin based Hennecke. These aspects make PU the ideal material for complex filter cartridge frames.
But the Dutch company's generally good experience was marred by quality problems in manufacturing and a high reject rate. Filtrair wanted to raise quality significantly and increase cycle times to two minutes per cycle on average, or six minutes per part.
Together with AutoRIM, a UK-based producer of hydraulic presses and BaySystems BÜFA of Germany for PU systems development, Hennecke generated a sophisticated overall solution that its says fulfills these criteria.
The solution involves a HK 135 high-pressure metering machine and a state-of-the-art MX mixhead. To meet the cycle times, three presses are used, arranged around the metering machine in a semicircle. The mixhead connects to each individual cavity by means of a pivoting boom.
Filtrair's new filter plant benefits from its suppliers' combined PU know-how. Hennecke said a modified outlet pipe, for instance, ensures extremely clean injection into the cavity. Meanwhile, carefully matched raw materials meet the customer's needs in terms of component properties.
The engineers take particular pride in a development made via a local mould maker, where the filter insert is already fixed in place when the mould halves are closing, so that it is seamlessly integrated into the PU frame.