Groche Technik GmbH, Plastifiziereinheiten

Plasticizing Screws – made for resistivity and longevity

Groche Technik at K 2010, Hall 13, Stand D 60
Plasticizing Screws – made for resistivity and longevity

Durable and sturdy plasticizing screws are among the special features Groche Technik GmbH of Kalletal in Germany will be presenting at K 2010 in Hall 13, Stand D 60. These feedscrews do not reveal at the first glance that they have a lifespan of some three to four times and higher resilience of that available from conventional plasticizing screws. Because of the special tungsten-carbide coat-ing, essential for the processing of aggressive plastics compounds in the injec-tion moulding, MIM, extrusion and thermoset industries, the investment is justi-fied in each and every case – despite the increase in initial cost.

A wide range of applications
As Armin Groche, CEO of Groche Technik, explains, the screws and cylinders made in Kalletal, Germany, by this specialist company are suitable for all established raw mate-rials processed in the plastics industry. “We not only supply screws for standard ther-moplastic materials, but also feedscrews and cylinders for the processing of rubber and silicon. In addition, our offer includes plasticizing screws for thermoset materials. Here, durability is essential; that is why we apply special coatings. ”For the coating of the com-plex steel screws, Groche relies on 88 percent tungsten-carbide and 12 percent cobalt with a thickness of between 0.125 and 0.25 mm for plastics with a high percentage of fi-ber glass and low corrosion impact. With plastics of higher corrosion impact, the same coating is offered, but based on nickel. “For plastics causing extremely high corrosion, such as PFA, PMMA, PC or fluoric polymers, we offer our special coating GT4000 – based on nickel and chrome”, continues Armin Groche. Due to the new HVOF process – where screws are improved and refined – Groche Technik can guarantee twice the life span of the screws, with almost all applications.

Complex geometry
Coating and post-grinding are difficult processes with such a problematic screw geome-try. Therefore, Groche has entrusted a partner specializing with these tasks. The com-plete machining of screws with diameters of between 22 mm and 150 mm is completed at Groche. After that, coating and post-grinding takes place at the partner company, us-ing diamond tools and processes developed in-house. According to Groche, coating of the cylinders is carried out by other companies in the region. The cylinders gain lasting wear and tear protection from a process where a tungsten-carbide layer based on nickel is attached to them at extremely high speed. “Only then does the cylinder last with such a hard screw”, continues Groche.

Less wear and tear and improved cleaning
The special Groche coating ensures that wear and tear is reduced and anti-adhesion improved. For example, in the processing of PMMA and PC significantly better cleaning cycles are achieved: “Due to its hardness, the surface of the screw remains totally smooth. The uniform cycle time is reached because the screw remains as good as new after cleaning,” according to Armin Groche. An additional advantage is the extremely high temperature constancy, up to 600° C for the processing of high temperature plas-tics. Groche guarantees twice the life span of a screw. “But it could equally be three or four times better“, emphasizes Groche. However, the specially coated Groche screws are more expensive. It pays for users because of the at least doubling of the life span and the much reduced cleaning times. The Groche screws are equally suitable for proc-essers in the automotive, electrical and engineering industries.

Groche is close to its customers
To be close to customers is an essential principle for the company based in Germany’s North Rhine-Westphalia. The entire breadth of plasticizing technology for thermoplastic materials will be shown at K 2010. The company offers screws with diameters of be-tween 12 and 160 mm. At K 2010, Armin Groche is planning to focus on his regular cus-tomers and existing relationships are to be strengthened further. Of course, new cus-tomers play an important part too. Groche customers are, above all, based in Germany, then in Scandinavia, Austria, Switzerland, France and Eastern Europe.

Photo: (Thomas Behne):
- The “Long Life“ screw
- Screw tips

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Ref: 10-25-02, July 2010

Armin Groche
Am Lehmstich 12
D-32689 Kalletal
Tel.: +49 (0) 5264 – 65 661 – 0
Fax.:+49 (0) 5264 – 65 661 – 19