Robotics Case Studies
Efficient handling of metal sheets
Schmalz, Inc. Posted 04/02/2015
Holding force, lateral force absorption, adaptability to the work piece, long life, environmentally friendly design and a clear reduction in costs: With the suction pads series SAXM, the German producer of vacuum technology J. Schmalz GmbH, sets new standards in sheet metal processing.
The requirements of the automotive and sheet metal industries are increasing in complexity − a large part of this is due to the fact that increases in efficiency and reductions in costs are of critical importance to the competitiveness of a company. Recent servo press generations, that handle metal parts with vacuum, can deliver 16 - 18 stokes per minute, depending on the type of press and complexity of the component. Whether you can take maximum advantage of the efficiency of the machine, however, also depends on the capability of the vacuum system and the suction pads in particular. The ability of the vacuum suction pad to hold the work piece, absorb lateral forces, adapt to the work piece and resist wear is ultimately responsible for process reliability and transport speed when working with metal sheets.
J. Schmalz GmbH, renowned producers of vacuum components, has developed a series of suction pads that differs in both design and material and is superior to other metal suction pads currently available. Suction pads of the SAXM series feature a large stroke that allows them to adjust optimally to work pieces with complex contours. The suction pad geometry provides all the features required for the highly dynamic handling of metal sheets: minimal pick-up times, high intrinsic stability while suction is applied and the absorption of extreme holding and lateral forces, especially on oily surfaces. The use of a cutting-edge and innovative material makes the suction pads extremely resistant to wear, even when subjected to ozone or aggressive drawing oils.
Improved dynamic handling, decreased costs
Until now, it was a simple rule of three: The faster the press, the more suction pads required. The more suction pads used, the more tooling work required. The more complicated the tooling work, the heavier and the more expensive it becomes. The design features of SAXM suction pads are redefining the laws of vacuum handling. The special structure of the suction pad interior and the additional friction disc allow SAXM to absorb several times the lateral forces as compared to other available metal suction pads. This has a positive effect on the costs and output. On the one hand, the number of suction pads and thus the tooling expenses can be reduced, while maintaining the speed of the press. On the other hand, the speed of the press can be increased while maintaining the same number of suction pads. When using a single cavity tool, an increase of just one stroke per minute – when applied to a production year comprised of 250 working days with 20 hours of operation and three shifts per day – can result in an increase of 300,000 parts per year.
Adaptability and flexibility
Work pieces such as doors, fenders and valence panels have projecting edges and gaps that restrict the areas that the suction pad can be used. This is a point, where the advantages of SAXM are two-fold: SAXM suction pads provide a stroke that is twice as high as that of common flat suction pads, which allows it to adjust considerably better to the three-dimensional contour of the work piece. In addition, SAXM suction pads provide a high level of lateral force absorption while keeping the suction pad diameter comparatively small. This allows for more flexible positioning on the contoured metal sheet when space is limited versus other common metal suction pads with larger diameters.
Long-lasting and environmentally friendly
Constant exposure to ozone, such as from welding auto body parts, can cause suction pads to become brittle over time. Contact with aggressive drawing oils, such as those used in presses during forming operation, can cause suction pads to swell. Both can result in vacuum system leakage and increasing energy costs. In the worst case, they can even cause system failure and machine downtime. SAXM suction pads are made of the innovative material Elastodur, which neither ozone nor drawing oils negatively effect. The increased service life that the material makes possible results in further advantages: The low amount of wear not only increases the reliability of the system, it also reduces purchase costs and general costs: The long lifetime brings about less machine downtimes, in which worn suction pads have to removed and new ones installed. SAXM suction pads are 100% recyclable and feature a modular design. You can quickly and cheaply replace individual suction pad elements, such as elastomer parts, friction elements and connection elements, which can then be correctly sorted and recycled.
The SAXM series of suction pads made from Elastodur with a Shore hardness of 85 is available in seven sizes with suction areas of 30, 40, 50, 60, 80, 100 and 115 mm in diameter. They can be supplied with various threads already assembled or as individual parts.