Smaller volume, less transport requirements, easy to recycle: special-purpose shredder for fully automatic processing of bulky sprues.

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1 Zinc die-casting: new solution for processing material residues Smaller volume, less transport requirements, easy to recycle: special-purpose shredder for fully automatic processing of bulky sprues. One of the most economic and technically best methods of manufacturing zinc components is to use modern zinc die-casting. It is now a standard process in a wide variety of industries, thanks to its ability to automatically produce large run numbers in a short space of time. Another advantage of the process is that zinc residues can be melted down and recycled without any drop in quality. But it is at precisely this point that many systems have a problem when it comes to waste disposal and recycling: the left over sprues, in particular, require a lot of storage space, and need to be transported away manually. This is not only intensive in terms of time and money but also requires additional personnel. However, one of the world s biggest manufacturers of furniture fittings, the Hettich Group, knows how to deal with the problem: a custombuilt shredder made by Erdwich Zerkleinerungssysteme GmbH is used to automatically shred even large pieces of waste zinc, rendering the former space and logistics management system largely superfluous. Particularly with high-cavitation moulds, sprues are a major problem, says Helmut Vogel, who supports and advises Hettich in planning its new system. For years, the production of furniture fittings proved an expensive process, requiring additional personnel, a lot of space, and high transport and disposal costs. To simplify these complex and expensive work processes, the management decided to install an automatic air transport system, which was already in use in another part of the company. There, the parts are transported by a stream of air, generated by a fan, through pipes from the point of entry all the way to the storage point or the locations where the next stage of work is performed, says Vogel, explaining the principle of the AirMove system. The shredder shreds the pieces to a precisely defined size However, as the system was only able to transport parts with small dimensions, Vogel looked for a way to reduce the size of the sometimes very large sprues to the right dimensions It is important that the shredded material complies with a certain dimension, is as uniform as

2 possible, and only has a low proportion of fine material, says Vogel, explaining the difficulty involved. The single-spindle M600/1 shredder made by Erdwich GmbH to comply with the demands of Hettich is now operational and ensures that the pieces are shredded down to a precisely defined size, which saves a great deal of space in their subsequent processing. In this way, not only the finished parts but also the sprues can be transported in the air stream, says Vogel. To enable a fully automated waste disposal process, all the machines are integrated directly in the zinc die-casting plant. First of all, the parts produced in the hot chamber of the diecasting machine are transported along a conveyor, along with the residual material, to a separator drum. Here, the parts that were hitherto not separated off in the machine are now isolated, with the finished parts and the sprues landing on two separate conveyors. The articles are then transported by air stream either to the warehouse or the next work stage, while the sprues and other residues are fed into the Erdwich shredder. Once these have reached the required size, they are transported by the AirMove system through a separate pipe either to silos or to be melted down. The plant is operational 24 hours a day, 7 days a week Central factors to be considered while developing the shredders was that production had to continue uninterrupted and that the air stream was able to transport the zinc residues with no problems, explains Jürgen Graf, head of marketing at Erdwich. To meet the specific requirements presented by Hettich, a single-spindle solution was chosen, consisting of a rotor and stator cutter: the material is held by the cutting rotor and cut by the stator blade. This process is repeated until the material has attained the prescribed size and falls through the sieve positioned below. The specific geometry of the cutter and the shapes of the blades mean that even soft parts can be cut very precisely, says Graf. As Vogel says, the shredder system is now in constant operation at Hettich: such requirements demand a robust construction, which must also be easily accessible to facilitate service operations, says the expert. The new concept, by which the parts and the sprues are separated from each other, sorted, shredded and taken away, has led to a considerable reduction in the logistics problems in the company s zinc activities.

3 Background Erdwich Zerkleinerungssysteme GmbH was first founded by Hans Erdwich in 1971 as a mechanical and metal engineering company. It now has 30 employees. The three core activities of the machine and plant engineering firm comprise the reconditioning and recycling of reusable materials, disposal of all types of hazardous waste, and the shredding of waste for the purpose of volume reduction. In the refrigerator recycling plant segment, Erdwich GmbH is one of the top three companies in the world. The Hettich Group is one of the largest manufacturers of furniture fittings in the world. Its more than 5,500 employees are responsible for developing intelligent furniture technologies. With 37 branches and subsidiaries and production facilities in America, Europe and Asia, the group is able to serve customers all over the world. As specialists in each market segment, the developers are able to adapt the products in each market segment to the demands of the various industries and customers. Hettich are partners to the furniture and white goods industry, specialist retailers, craft trades and the do-ityourself sector. Image material: Image ID: Zinkangüsse nach der Produktion (li) und geshreddert (re).jpg Caption: Zinc products in particular are generally so bulky that they need a lot of space and require manual transportation. Using the Erdwich shredder, the production residues are shredded so that they require a far smaller amount of space and can be transported automatically by air stream. Source: Helmut Vogel

4 Image ID: Schneidwerk.jpg Caption: The single spindle shredder consists of a rotor and stator cutter: the material is held by the cutting rotor and repeatedly cut by the stator blade until it has attained the prescribed size. Source: Erdwich Zerkleinerungssysteme GmbH Image ID: Zerkleinerungsanlage.jpg Caption: The M600/1 single spindle shredder made by Erdwich Zerkleinerungssysteme GmbH ensures that parts are shredded to a precisely defined size, thus saving space in their subsequent processing. Source: Erdwich Zerkleinerungssysteme GmbH Image ID: Hans_Erdwich.jpg Caption: Hans Erdwich is the CEO of Erdwich Zerkleinerungssysteme GmbH, based in Kaufering. Source: Erdwich Zerkleinerungssysteme GmbH

5 Image ID: Helmut_Vogel.jpg Caption: Particularly with high-cavitation moulds, sprues are a major problem, says Helmut Vogel. Source: Helmut Vogel Further information for readers, viewers and any other interested persons: Erdwich Zerkleinerungssysteme GmbH Hans Erdwich, CEO Kolpingstr 8, Kaufering Tel: , Fax: infoline@erdwich.de, Internet: trio-technik AirMove GmbH & Co. KG Am Rottland 19, Meinerzhagen Tel: , Fax: info@trio-technik-airmove.de Internet: Further information for editorial purposes Pressebüro Beatrix Gebhardt-Seele Leonrodstraße 68, Munich Tel: , Fax: pressebuero@gebhardt-seele.de Internet: Reproduction free of charge, stating the source. Please send sample copy