With a gripping system consisting of 1200 packaging suction pads, vacuum specialist Schmalz has closed one of the few gaps in the automation process of Deutsche Post's logistics centres. The system provides maximum flexibility and holding force in a robot cell for automatic depalletising and separating of cardboard boxes.

Ordered today and delivered tomorrow. The development of the distribution channel from a functional tool to a decisive purchasing incentive has contributed to the fact that the mail-order business has been the booming segment in the logistics market for years. Today, consumers expect the option of ordering online just as much as they expect a delivery within 24 hours or the option of returning goods for free. This results in high demands that are placed on the logistical process chain: minimal transport routes and times, different package sizes, flexible shipping volumes.

What is pivotal for these processes are Deutsche Post's logistics centres, where mail-order catalogues as well as the offered merchandise is palletised and picked for domestic transport. The unloading and breaking up of these pallets is one of the few work steps still done by hand. Deutsche Post classifies the lifting and rotation movements occurring during this work step as physically very stressful.

For this reason, Bremer Institut f?r Produktion und Logistik GmbH (BIBA) and Br?hmig GmbH from Radeberg have been involved in the project called "Robot Cell Light Depalletiser." The goal of this cooperation was to develop a cheap and yet powerful automation solution. "We put our emphasis on maximum versatility of use and avoided unnecessarily complicated technology," says CEO Mr Lutz Br?hmig, describing the development project. Vacuum specialist J. Schmalz GmbH from Glatten was selected as the partner for the gripper technology.

Flexible Automation Solution in Demand

Following requirements for the depalletising unit resulted from the project planning phase: Firstly, the unit should be able to pick up any piece goods, which mostly have closed and flat surfaces, in layers from the palette and separate them on a conveyor belt. Secondly, the unit should deployable where the greatest parcel volumes occur without a large amount of upgrading or installation. And thirdly, manual loading of the coder lines should still be possible when required.

The result: an extremely compact depalletising unit with dimensions of only 1800 x 3200 x 3400 mm, which can be moved using a standard forklift or transported on a truck when put in transport position. The main components of Br?hmig's depalletiser BD 200 consist of a two-axis portal, a vacuum layer gripping system, electrical vacuum generation and the necessary safety technology. In addition, the depalletiser has an automatic position sensor function and an optional automatic pallet changing function.

The Right Suction Pads are Key

When configuring the gripping system, attention was focused on the selection of suitable suction cups in particular. After performing practical suction and lifting tests, the choice fell upon Schmalz's suction pad series SPB1, which was specially developed for handling cardboard boxes and stable packages. Dennis Kilb, industry segment manager for packaging at Schmalz, describes the importance of the suction pad for the entire unit as follows: "The suction pad alone interfaces with the various kinds of cardboard boxes. With that in mind, it is clear that the suction cup's performance, with regard to its sealing ability and service life, is a major factor in guaranteeing that the entire unit functions reliably. Here, the suction cups of type SPB1-25 ED-65 have decisive advantages."

Its design features, such as the reinforced basic body with 1.5 folds and adaptable sealing lips, gives it excellent sealing properties on porous and slightly distorted surfaces. Manufactured using Elastodur, an extremely wear-resistant material, these suction pads last three times longer than suction pads produced using conventional materials, such as Perbunan/NBR, contributing significantly to the high availability of the entire system.

In the Br?hmig depalletizer BD 200, a total of 1200 suction cups are assembled to create a complete layer gripping system. The gripping system is split into several vacuum chambers in order to deposit the cardboard boxes separately. Flow resistors in the individual suction cups ensure reliable gripping and holding of cardboard boxes even with various layer configurations and when suction cups are only partially covered. In order to generate a vacuum, a powerful, direct-drive blower with 7.5 kW rated power is used to provide a high suction volume and, therefore, making it ideal for handling porous workpieces. Even the design of the other components in the vacuum system benefited from having Schmalz on the team as an experienced partner.

A Complete Package that will Win You Over

"The developing partners cooperated well and developed a compact system with a high potential for increasing efficiency that for the most part dispenses with sensors, software, complex kinematics and systems interfaces," says Dipl.-Wi.-Ing. Kolja Schmidt, project manager of BIBA, explaining the benefits of low-cost automation solutions for users. The depalletiser shows off its advantages as soon as operations begin: Safe handling of cardboard boxes of various sizes, reliable separation with undefined layer configurations, flexible handling of process peaks, no changeover times when switching pallets and relieving the employees of physically strenuous and monotonous work.

The system's versatility allows for maximum utilization, thereby, guaranteeing minimum order processing time. The separation function offers an additional benefit which allows further tasks to be integrated into the process step, such as when scanning a label or when measuring and sorting within a sorting system.

The depalletiser BD 200 and the integrated layer gripping system is freely distributed by Br?hmig. Further vacuum gripping systems for all kinds of packaging processes are modified for customer specific requirements by Schmalz.

(Schmalz India Pvt Ltd, Pune is the 100% 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.Schmalz India Pvt Limited, Pune. Tel: 020-40725500. Fax: 91-20-40725588. Email: schmalz@schmalz.co.in)