These laboratory presses have to meet complex time, pressure and temperature specifications for rubber or plastic moulding tests, even under vacuum. In some cases, they are used almost daily in four-shift operation. This is not an off-the-shelf product, but a customised solution. The laboratory presses are used in universities and institutes as well as in industrial companies. While some are researching the strength of interior panelling made from renewable raw materials or the stiffness of carbon fibres on behalf of the automotive industry, for example, others are carrying out complex initial tests. This can involve very, very long machine running times. The product range consists of automatic, vacuum, moulding and manual lever presses. They can be equipped with heatable and coolable pressing plates that can reach temperatures of up to 400 °C. The press forces are up to 70 tonnes.
A number of special applications are realised with the various laboratory presses. When it comes to moulding presses, this can involve so-called 'ophthalmic plaques'. They are used for the long-term treatment of patients with cancer in the eyeball. Low-radiation isotopes are used. The machine is used to mould individual, trough-shaped geometries for medical technology. The customer's task was to realise a defined basic cycle for the production of radiant implants in a cold forming process using pressure. A cycle with regard to the individual cycle parameter values should be as repeatable as possible and freely programmable with up to seven individual steps. A total of 20 individual cycle programmes with individual combinations of values for pressure and time can be run and reproduced at any time. In another application, a vacuum press is used to apply gemstones to filler end caps. The way it works is very simple: the gemstone and the end cap blanks are inserted into the mould. The workpiece is heated, a vacuum chamber is created and then evacuated. The mould is closed and the upper and lower parts fuse together. The end cap with its precious contents can then be removed. One cycle takes around 30 minutes. In total, over 500,000 end caps have now been produced without any problems.
Basically, the main requirement is always that the press plates close. They should also be as parallel to each other as possible. This means that plane parallelism is also important. The pressing function and plane parallelism are realised via the column guide. In addition, the columns must be able to withstand high temperatures - up to max. 300 °C - in the short term.
