Lisco from Bargteheide in Schleswig-Holstein uses ACE structural dampers as safety elements in many of its designs. The core of Lisco's service portfolio includes standard and special axes as well as complete linear axis systems. They can also be equipped with drive, control and measurement protocols.

In order to understand the dangers involved in the production of silicon wafers, which are used as starting products for semiconductor components such as solar cells, their background in the photovoltaic industry must first be examined: Their production usually takes place in a clean room. This means that there are no people present in the production halls. However, they are still responsible for the control process. This applies not only in the control rooms in front of computers and other screens, but also in the planning of the machines.

A successful design is only one that has been thought through to the end. In today's world, this not only includes protection against accidental disruptions, such as power failures, but also protection against intentional damage, such as cyber attacks. In times of increased white-collar crime, this is a factor that should not be underestimated. Lisco's loading unit takes all this into account.

Lisco design with turntable, toothed belt and spindle drives © ACE

Toothed belt and spindle drives
To transport the wafers into the ovens and position them there, Lisco has developed high-quality spindle and toothed belt drives and, in a further step, integrated a turntable. The toothed belt drive is responsible for moving the feed to the ovens, which resembles a baking tray, forwards and backwards and develops a maximum toothed belt force of 2,100 Newton meters with a maximum torque of 180 Newton meters at the drive shaft. The repeat accuracy is 0.05 millimetres, which is why the baking process takes place automatically in a clean room. This is because such precision cannot be achieved by human hands.

The spindle drive is even more precise when raising and lowering the feed. Its error tolerance is just 0.03 millimetres. Available with three different spindle pitches, the dynamic load ratings are between 19,540 and 30,360 newtons, depending on the model. The static load ratings are even significantly higher. However, due to the positioning task, they are not of decisive importance in this application.

As a further design element, the turntable is mounted in the middle of the unit like a floating platform and is used for additional position optimization. For this purpose, it can also be controlled from the control room in any rotation. Tubus TR-97 structural dampers from ACE are used to protect the turntable and the structure above it, which is made of aluminum profiles reinforced with sheet metal. These serve purely as safety elements in the event that ball screw nuts are defective and the unit may sag downwards. They also provide excellent protection against the above-mentioned damage when controlling the software.

ACE tube structural dampers integrated by Lisco to secure the structure © ACE

Round thing
The structural dampers made of co-polyester elastomer are a good alternative compared to industrial shock absorbers if, as in this application, the precise stopping of moving masses is not important. This ACE product series alone comprises eight different tube designs with a total of around 150 standard individual solutions for a wide range of applications. The compact components can be used to generate almost linear, degressive or, as in this case, progressive characteristic curves.

The individual types of the TR family used here damp radially, whereby this type of load produces a long, soft deceleration with a progressive reduction in energy at the end of the stroke. As Lisco's loading unit weighs around 600 kilograms, the designers decided to select representatives of the TR-HD type, which are characterized by both a solid design and high force and energy absorption with a short damping travel.

Their low overall height with strokes of twelve to 44 millimetres and high energy absorption of 405 to 11,840 newton meters were the decisive factors. Even though these characteristics mean that they are mostly used in agricultural engineering, shipbuilding or off-shore, on conveyor systems, on shovels or articulated joints of construction machinery as well as on loading and lifting equipment, some TR97-31HD tubes are now also performing reliably in a factory for the production of solar cells.

Tubes from the TR-HD family are supplied with two screws and are quick and easy to attach both horizontally and vertically. © ACE

Available from stock at ACE in Langenfeld within 24 hours in most cases, the maintenance-free, ready-to-install dampers have a long service life in addition to their flexible damping properties. In addition to a very long service life of up to one million load cycles, they stand out from all other solid damping elements due to their space-saving design and low weight. In addition to the standard products of the individual Tubus families, ACE also offers a wide range of special designs for customer-specific applications on request. as