J. Schmalz GmbH introduced modular gripper system for the modular design of vacuum end effectors (VEE)

21-8-2013 — /EuropaWire/ — Speed and flexibility are the main challenges for industrial packaging processes. J. Schmalz GmbH has developed a modular system for the modular design of vacuum end effectors (VEE). As a technological comparison shows, this system, as an alternative to conventional design and manufacture, can save time and money when constructing a gripper for packaging machines.

According to the “Configuring rather than designing” principle, Schmalz offers a modular system comprising different individual parts which can be combined using easy-to-operate configuration software to form an individual gripper (www.schmalz.com/vee). The key idea is to be able to configure and modify grippers immediately, rather than having to spend time and money designing and individually manufacturing them. A technological comparison outlines the time and cost-related advantages the VEE system offers.

According to Schmalz’s research, conventionally designed vacuum grippers are at a bottleneck in terms of design, assembly and start of operations for customer-specific packaging machines. The reasons for this are due to complex and complicated processes from the design phase through to starting operation. Machine manufacturing companies / system integrators create offers for future machine users based on technical specifications or a process description. In many cases, product samples are not yet available at this stage, or they are only prototypes and are not the final design. When the order is placed, a detailed machine concept is then drawn up and design is begun. A vacuum gripper is usually only designed after the machine concept has been fully drawn up in detail.

According to Schmalz’s calculations, the design and manufacture of a gripper by a machine manufacturing company results in a design process and manufacturing period, incl. waiting times, of one to four weeks. This is also dependent on the machine manufacturing company’s range of manufacture. The waiting time for the new product can be further prolonged if gripper components are largely purchased. For complex workpieces such as flexible bags with comparatively little content, vacuum grippers also have to be optimized in order to achieve reliable results.

Frequent Product Changes in the Consumer Goods industry

The starting point for considerations at Schmalz was that, depending on the product life cycle or the product changes (size, shape, weight, feel), different grippers will always have to be integrated on the machine. Frequent product changes can, in particular, be observed in the consumer goods industry. New grippers for machines are thus needed relatively frequently. An extreme case in practice is bag packaging filled with bulk materials and liquids, refill pouches for liquid soap for instance. Often during the working day, varying bag formats are packaged because different product lines are often processed on one machine. In individual cases, machines are designed in such a flexible way that up to ten variations of a bag are processed and thus requiring ten different formats.

The product life cycle of products packaged in bags is considerably shorter than for products in bottles or boxes because changing the packaging unit and size for bottles and boxes is more complicated. On average, bag packaging changes its shape, color, packaging material, size or fill level every one to two years. This means that new grippers need to be redesigned every one to two years. The VEE system meets these requirements. Schmalz offers software that allows the user to combine various flanges, connectors and suction pads to create an end effector in just a few clicks.

The software can be used for free at www.schmalz.com/vee. The user has to log on, enter the workpiece specifications, the number of suction pads, the suction pad size, and the desired gripper version. Next, the user only has to define the suction pad positions and the connection components such as robot flange plates and the flange module for vacuum feed. All of the components are coordinated to compliment one another. Changes can be followed step by step using the live preview in 3D view. The 3D model of the gripper can be easily integrated into existing CAD design programs. Moreover, immediately after completing configuration, the user receives a detailed parts list and the technical data (e.g. mass) for the gripper.

The VEE can be configured with 1 to a maximum of 12 suction pads. Based on the requirements of their application, the user selects the suction pads they need from Schmalz’ highly specialized product range: for handling delicate plastic film or blister packaging, stable cardboard boxes, slightly flexible product packaging or filled bags and flow-wrap packaging.

The VEE can grip loads weighing up to 2000 g regardless of the product type and, with process accelerations of up to 10 g (100 m/s2), it meets the speed requirements for the pick and place processes that are typical for the packaging industry. A further advantage: the standard quick-change adapter reduces changeover times for the VEE to a minimum.

This makes it well-suited to the consumer goods industry where a large range of products are handled in smaller and smaller batches. Another advantage of the VEE is the hose-free vacuum distribution within the system, which reduces possible leakage and ensures greater efficiency and faster response times.

Schmalz’s analysis shows that the net time requirement for conventional grippers is approximately 13 hours from definition, design, manufacture through to assembly. If grippers are manufactured with a clamping function, and thus cannot be adjusted, additional manufacturing capacity must be scheduled, set up and completely newly manufactured.

Depending on how much machine manufacturing companies / system integrators produce internally, delays of a few hours to days can result. In the end this can result in a design and manufacturing period between 1 and 4 weeks. The VEE system; however, reduces gripper definition and assembly work to about an hour.

Using the VEE system also reduces the costs of gripper design to a fraction as opposed to conventionally designed grippers. If you add the costs from the initial handling test through to the start of machine operation and include a format change and a product fill level change, the total costs for the VEE are EUR 720. The costs for a conventionally designed gripper on the other hand are EUR 3,700.

Gripper costs within the product life cycle of a packaging machine from the initial handling test with product samples, start of operation through to format change. Format change or fill level change takes place approximately every 1 to 2 years. The steps (4) to (5) are thus repeated.
A waiting time should also be included in steps (4) to (5): All VEE parts are kept in stock and are available in a few days; for conventionally designed grippers, the waiting time varies depending on the machine manufacturing company’s range of manufacture and capacity

Clean Surfaces

All VEE elements are made of FDA and BfR-compliant polyphenylsulfone (PPSU). The surfaces of the elements are easy to clean and are resistant to alkaline cleaning agents. This makes them suitable not only for the packaging industry generally but especially for use in the food processing industry.

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Modular vacuum end effector VEE with flexible format changes