Energy and efficiency in a double-pack

Two vacuum lifting devices ensure secure and gentle handling of plastic sheets, streamlining material flow while manufacturing housings for photovoltaic production equipment
As an international growth market, the photovoltaic industry is characterised by its dynamic development. But increasing competitive pressure is not just pushing cell and module manufacturers towards streamlining. Plant constructors also need to pull out all the stops when it comes to productivity, flexibility and quality in order to stay competitive for the long term. For decades, Gebr. Schmid GmbH + Co. in the Black Forest has been the world leader in equipment technology for the production of circuit boards, flat panel displays and photovoltaic components. Besides brand new, high-capacity production plants, Schmid has also invested in a suitable material flow environment. The goal was not only to fully exploit the potential of the high-tech machines (thus increasing their efficiency), but also to free the employees of physically strenuous side tasks.
The task: handle heavy plastic sheets with ease and lay them down right on targetSchmid uses high-strength plastic sheets made from polypropylene for the housings of its photovoltaic production systems. In the past, handling the sheets that measure up to 3,000 x 2,000 x 15 mm and weigh up to 100 kg always created problems. First, handling these unwieldy sheets required up to six people, some of whom had to be brought from other workplaces. Second, it was difficult to load the sheets onto the machines due to the accuracy required when laying the sheets down. Accuracy is necessary because the table for the machining tools is equipped with a grid system so that the plastic sheets can be vacuum clamped for precise machining. Time and again, when laying the sheets down, the sealing cable would slip out of its groove, so that the vacuum required for clamping could not be established. This brought with it having to make complex, manual adjustments while the machine was idle.
To avoid this, Schmid decided to invest in a complete material flow solution. J. Schmalz GmbH, a manufacturer of vacuum technology with whom several projects had already been successfully carried out, was chosen as the partner. The exemplary complete solution involves loading a panel saw and subsequently loading a CNC lathe/milling machine. That is why two different handling solutions were used for Schmid. To load the saw, a VacuMaster Basic 500-90-8-2400 vacuum lifting device with a 300 kg load capacity has been installed on a one-beam crane system with aluminium crane rails. The sheets are first removed in a horizontal position from drawers in an automatic, high-rack storage area by using the vacuum lifting device. They are then transported by the one-beam crane system to the saw and laid down on the machining table. After sawing, the blanks are removed from the table. For further internal transport, the blanks must be rotated by 90° and set down upright on a trolley. To do this, the vacuum lifting device is equipped with an electronically operated swiveling unit, which allows the sheets to be swiveled continuously and without jolting at the push of a button. To ensure a secure grip on the sheets and blanks, the 2,400-mm long load beam is equipped with four 750-mm long, lateral cross arms, to which a total of eight SPU suction plates with jointed mountings are fitted. The lifting device is guided by the smooth one-beam crane system, which makes a large-scale work area of over 100 sq. metres available. Within this area, the unmilled boards and blanks can be handled with complete freedom and flexibility by just one person.
The solution: two vacuum lifting devices from the VacuMaster modular component systemLikewise, the handling solution for loading the CNC lathe/milling machine also involves the use of a vacuum lifting device from the VacuMaster Basic series with the electric 90 degree swiveling feature. The modular construction system allows the VacuMaster Basic 250-90-4-1600 used here to be adapted for the smaller blanks. The device can handle a load of up to 200 kg and combines a 1,600-mm long beam with two lateral cross arms, each 750-mm long. While the same suction plates as on the first lifting device are used, the number was reduced to four, given the smaller dimensions and weights of the blanks. Also new is the combination with a slewing column crane featuring a 6,000-mm long aluminium boom, from which the lifting device is suspended. The VacuMaster takes the blanks standing from the trolley, swivels them and lays them down horizontally on the machining table. After machining, the operator removes the finished parts, once again using the VacuMaster, and hands them on for further use in assembly.
Both the large and small lifting devices use electric vacuum pumps to generate the vacuum, with a suction volume of 8 and 4 cubic metres per hour, respectively. When it comes to safety, no compromises are made: large vacuum reservoirs and the large suction pad surfaces work together with quick-action non-return valves to prevent the load from dropping, even if the power fails. A further advantage of the reservoir is the lightning-fast pick-up response for repeated lifting processes. Using the vacuum lifting device is comfortable and safe with the ergonomically formed operator handle, on which the pendant controller for the chain hoist can be easily placed. Because strict attention was paid to the lightweight construction of the crane system used, moving and positioning the sheets is consequently very smooth.
Summary: work made easier with a safety bonusWork has been made a lot less strenuous for the employees, thanks to the easier handling. Personnel costs have been reduced to the extent that the work capacity can now be better used, since the staff now has much more time for other valuable tasks. Unproductive downtime could be reduced heavily by cutting out the task of making positioning corrections and faults when creating the clamping vacuum. The success reached with the integrated material flow and handling solution as summarized by Karl-Heinz Gaiser, departmental manager for vessel production at Schmid: “Transporting sheets was costly and required up to six people. Now it is much easier with the lifting devices from Schmalz!”
The companySchmalz India Pvt. Ltd. is the 100 per cent subsidiary of J. Schmalz GmbH, headquartered in Glatten in the Black Forest, Germany, is one of the leading suppliers of vacuum technology worldwide. Its portfolio includes high-quality products and services in the area of automation, handling and clamping technology. Founded in 1910, the company with a proud tradition, offers innovative and efficient vacuum solutions to customers from many different industries. The company has a total of 600 employees at its headquarters in Glatten (in the Black Forest region of Germany) and at its 16 overseas branch offices.