At the BMW Group’s light metal aluminum alloy foundry in Landshut, Germany, scrap such as punchings and sprues are recycled and then re-melted.
Previously, die-cast scrap was collected in containers without being shredded and was removed from the basement of the foundry with considerable use of manpower.
In the course of a renovation of the foundry, Igling, Germany-based Erdwich Zerkleinerungs-Systeme GmbH was awarded a contract to design a plant that enabled the collection and shredding of the foundry’s aluminum scrap directly from punching presses. Erdwich recommended its RM 1350 preshredder as part of the system.
Onsite shredding means containers with scrap parts and punchings can be transported far less frequently to a large container, creating an operational efficiency. Working with the technical department of the BMW Group, Erdwich also developed a safety system for monitoring the condition of the machine.
BMW Group bills its light alloy foundry in Landshut as one of the most modern foundries in the world. Every year, around 5 million aluminum castings weighing a combined 84,000 tons are produced there using five different casting processes. The castings include engine components and structural components for vehicle bodies.
The cast aluminum parts to be shredded have dimensions of up to 2,000 millimeters (mm) by 1,400 mm (78 inches by 55 inches), and therefore had taken up a lot of space in the collection containers. This, in turn, meant the containers had to be emptied frequently, which required a great deal of time and manpower.
Erdwich, which has decades of experience in the construction of recycling plants, got the order to plan and commission the metal shredder. “When we visited the site, it quickly became clear that the solution required in the tender would not have the desired effect,” says Richard Adelwarth, an Erdwich project manager. “We therefore carried out many trials and consulted another company in the industry, with whom we regularly work on larger projects in order to be able to offer an optimum solution.”
The company subsequently designed a machine based on its RM 1350 preshredder. That model is characterized by what the company calls fast and easy maintenance, a long service life, optimum shredding and high throughput.
To date, seven systems with soundproof enclosures have been installed for the eight casting cells and punch presses in the BMW plant. “Loading takes place in free fall; that means the molds, which are to be returned to the melting process, now fall from the pressing plant directly into the hopper of the preshredder and then into a container measuring 1,400 millimeters by 1,400 millimeters by 900 millimeters (55 inches by 55 inches by 35 inches),” says Adelwarth.
When the container is full, it is taken outside and emptied into a larger container which in turn is brought to the smelter. The shredding process has reduced the volume of cast parts by 50 to 60 percent, which means the disposal containers have to be emptied far less frequently, and thus require less time and manpower, according to Erdwich.
The preshredders were adapted to operating conditions present on-site. The drives of the machines, for example, had to be mounted on one side instead of the usual two. This was because the building includes columns located near the installation site, necessitating a narrower design.
The standard version of the RM 1350 already has a safety system that includes a process logic control (PLC) system with automatic reverse and cut-out control, so the machine is protected from damage in case of overload or the introduction of a bulky solid part. Additionally, each shaft is equipped with an energy-optimized frequency converter designed to ensure the two cutting gear shafts are driven separately. This enables optimum adaptation to the shredding process, says Erdwich.
“Both the filling level of the removal box located in the basement and the monitoring of the shredder itself are now displayed transparently, so that a quick response can be made if necessary,” adds Adelwarth. referring to additional safety measures taken in cooperation with the BMW Group.
As the casting house renovation continues, a conveyor belt system is being planned to further optimize the disposal process. With the belt, shredded rejects would no longer be collected in the initial containers that have to be removed and emptied by hand. Instead, the rejects would be transported directly into the large container via a conveyor belt. In this way, scrap from all casting cells can be disposed of simultaneously and without additional logistical effort.
Erdwich says in the current expansion stage it has been able to meet the requirements placed on its system, helping the BMW Group to “considerably accelerate” its work processes.
Erdwich Zerkleinerungs-Systeme GmbH was founded in 1972 and has 42 employees. The company supplies recycling, reprocessing and volume reduction equipment, including specialized recycling plants for refrigerating devices.