Teklas uses PP in WIT production

The Turkish company Teklas Kaucuk, which celebrated its 40th anniversary in 2011, has built up core activity in rubber media ducts, anti-vibration parts and windscreen wiper blades.

The company established a plant in Kardjali, Bulgaria, in 2006 and started to use water assist injection moulding technology at the plant at the end of 2009. That first WIT line consisted of a KraussMaffei KM 150-370 CX injection moulding machine and a PMEcube WIT module from PME Fluidtec.

The WIT line has been used to mould 3D cooling water ducts for an Opel 1.4 litre car, using tools from Hofmann Werkzeugbau. Opel originally foresaw a long and complex metal duct, but it finally decided on a plastic version in BASF's special Ultramid A3HG6 WIT grade of polyamide 66.

BASF said in November 2011 that Teklas has since supplied a large range of engine compartment cooling water, air and oil ducts made of the special Ultramid material to "almost all large European automobile manufacturers."

Teklas now has four KraussMaffei machines using WIT in Bulgaria and one at its headquarters in Bayrampas, near Istanbul. These are supplemented by eight Engel vertical machines, four each in Bulgaria and Turkey, that are used to overmould hoses, as well as three 3D blow moulding machines in Turkey.

Teklas uses the "melt pushback" version of the WIT process, while post-moulding robotic systems apply metal rings and TPE seals to the WIT ducts.

Looking at other technologies, Teklas told European Plastics News that a completely new development in 2011 was its use of a special Polyfort unreinforced polypropylene from Schulman. This material will this year be used for serial production of automotive drainpipes with integrated flexible bellow sections that facilitate assembly and allow for movement during driving.

European Plastics News spoke to Teklas' new business development and R&D director, Murat Bozkurtlu, and Schulman's innovation manager, Thilo Stier, on Schulman's stand at Fakuma 2011. Bozkurtlu said the new PP plastic duct made in the WIT process is a substitute for a rubber duct that Teklas was blow moulding for Opel.

At the time of the Fakuma meeting, Bozkurtlu said prototype tools had already been cut and he showed an example of a moulding produced on these tools (pictured above). The tools were made by the local Turkish mouldmaker Elvanlar Plastik, based in Gebze, within an eight-month development time. Teklas says it carried the full cost of the prototype tools.

While the example showed at Fakuma had one bellow section, Bozkurtlu said a two-bellow version has been designed for serial production by using hot runners. This first plastic version of the pipe belongs to the Opel "Delta" platform that includes the Astra car; there are around 1.5m Delta platform cars in worldwide production.

The two-bellow series production tool was ready at the end of January 2012 and another 12 tools will follow by the end of March for serial production of a number of PP ducts and other items, Bozkurtlu said last month.

"The established blow moulding solution makes no sense compared with the highly integrated PP plastic version" if you consider the blow moulded part's need for clips to be assembled onto the ducts, says Bozkurtlu. The integrated bellows on the WIT ducts replace O-rings applied to the blow moulded ducts, although Bozkurtlu says the injection moulded version also uses O-rings, but these are "just for sealing".

Stier points out that the special Polyfort PP material has sufficient melt strength to withstand not only the application of water in the WIT process to from a tubular structure, but also a second "blowing" application of water to form the integrated bellow sections. Teklas has applied for a patent for this special technique.