Attraction of magnetic clamping for EN 289 safety compliance

Posted on 16 Jan 2015 by Tim Brown

Machine engineering company, Wickert Maschinenbau, has turned to Roemheld’s latest magnetic clamping technology to ensure compliance with the UK's new EN safety regulations.

To date, M-TECS magnetic clamping plates are the only ones with a control system that meets the high demands of the new EN 289 safety standard, which came into force at the beginning of 2014.  Wickert installed the latest version of the quick-clamping technology, for the first time, on a compression press for the production of pharmaceutical stoppers.

Their customer was a company in the US, which sometimes produces very small batches under white room conditions.  Thanks to the technology, the customer has saved more than two hours’ tooling time at each of the frequent mould changes.

The WKP 10000 S press, with its 10,000 kN press force, is being used to produce caps for medication packages and plungers for injections with diameters between 6 and 16 mm. Production takes place in a white room, meeting the requirements of ISO Class 7.

The American pharmaceuticals company processes an elastomer, developed in-house, whose properties are adapted to the medications with which the work pieces come into contact. Air pockets, that occur in the starting material during kneading, are eliminated in a vacuum chamber. The elastomer vulcanises at a temperature of 180°C to 210°C.

As the dies used are only 2″ (5 cm) thick in some cases and require a plane parallelism with a tolerance of only 0.1 mm over the whole press platen area of 1,000 x 1,000 mm, they have to be clamped absolutely level.

Equally as important, is the homogeneous distribution of the temperature; it must not deviate by more than ± 1°C over the whole area during forming.

A further demand on the clamping devices is made by the geometry of the tools used: Some work pieces are given a Teflon core; the moulds used here have up to 3,500 cavities so that high clamping forces are required for secure holding. The lower mould half can also be pulled out to the front for loading.

“In our experience, magnetic clamping technology satisfies these demands best,” said Thomas Klimpl, Sales Engineer and Head of Marketing at Wickert Maschinenbau GmbH, explaining the reason for the decision in favour of the clamping plates.

The current order is the first joint project in which magnetic clamping plates have been used, together with the control system adapted to the new regulations. Andreas Reich explains: “We have designed the new control system so that it fully satisfies the demands of the interface with safety category IV or performance level “d” and “e” of the press standard EN 289.”

Thomas Klimpl, who originally began at Wickert as a design engineer, estimates that around 200 M-TECS magnetic clamping plates from Roemheld are in use on Wickert presses: “We have a large number of customers from the aerospace industry where small quantities are frequently produced. With frequent tool changing, the magnetic clamping technology is unbeatably fast.”

The operating temperatures of generally above 150°C also speak in favour of the technology. Hydraulic clamping elements are seldom used at Wickert for the same reason.