After presenting the first example of its entirely new generation of large-scale trim-in-place moulds for 70 cups at the NPE exhibition in Chicago in June 1997, Marbach Werkzeugbau GmbH (PO Box 2624, D-74016 Heilbronn) has now shipped a 96-cup mould to North America. It is capable of producing up to 100,000 polypropylene dip cups an hour. Marbach reported that, over the past few months, four moulds with 40 and 70 cavities have also been successfully commissioned in the USA. Temperature control featured as the most important issue during development of these moulds, since trim-in-place moulds for polypropylene have to dissipate a large amount of thermal energy from the sheet during each cycle, while cutting clearance is just a few microns (a couple of ten-thousandths of an inch) and permits virtually no temperature variation. A complex system of cooling circuits and a sophisticated temperature control unit keep wear on the mould to a minimum.

According to Marbach, large-scale moulds such as these make it economically worthwhile to change from injection moulding – which has so far dominated this segment of the market – to thermoforming. Apart from this, a large number of polystyrene products, which are traditionally thermoformed and post-trimmed separately in the USA, are switching to polypropylene and the trim-in-place mould. Marbach therefore sees very good market prospects for its tooling technology in the USA, particularly as the new service center in Elkhart, Indiana, which was opened last year, is now fully operational and can offer direct support to new PP converters.

READER SERVICE: Company brochures Marbach Werkzeugbau (German / English): Company profile: PIE-No. 41089 – Brochure "Thermoforming Tools for Cups": PIE-No. 41090 – Brochure "Thermoforming Tools for Lids and Dishes": PIE-No. 41091.