Future-oriented metal recycling : De Rooy relies on WEIMA solutions for briquetting and dewatering

De Rooy specializes in grinding, milling, and precision measuring of steel – and that in particularly large dimensions. The family business, founded in Eindhoven in 1939, now employs over 110 staff and is active in various industries. These include the offshore, semiconductor, and food industries with products such as casings, blades, bearings, and shafts that require precise processing despite their size.

During steel processing, grinding processes generate so-called grinding sludge. This grinding sludge consists mostly of fine steel and corundum particles as well as oil (80%). Disposing of this waste is very cost intensive for De Rooy and similar companies. In search of a sustainable and more affordable solution, the collaboration between De Rooy and Dormatec Environment Systems was established. Jos Schouten, Production Manager in the milling department at De Rooy, explains: "We wondered how we could save on transport costs and at the same time help the environment. WEIMA convinced us with their solution for the grinding sludge and their machine."

The C.200 press from WEIMA contributes to efficient residual material processing by dewatering and compacting the grinding sludge. The press is characterized by a simple and robust construction. A hydraulically operated cylinder with a compaction ram compacts the grinding sludge to almost dry. The briquettes, with a diameter of 200 mm, are then ejected through a discharge pipe. The dewatered coolants, emulsions, or oils are collected in a trough and can then be reintroduced into the machining machine. In the case of De Rooy, the grinding sludge consists of up to 80% oil.

"We can secure the oil and return it to our machine, which is about 100 liters a day. This way, we not only save on transport and money but also resources by recycling the oil," says Jos Schouten. De Rooy can then dispose of the nearly dry sludge properly or sell it. If necessary, new metal can be obtained from it by melting. Thus, the cycle is closed.

De Rooy specializes in precision milling of machine parts in various market segments. With the largest CNC milling machine, workpieces measuring up to 14.500 x 4.600 x 2.850 mm and weighing nearly 50 tons can be processed. Depending on the machine part being manufactured, a large amount of aluminum chips is produced during milling operations. The WEIMA TH 1500 compresses these aluminum chips without binders or adhesives, reducing the volume by up to 90%.

In the first step, an auger conveyor transports the aluminum chips from the milling machine into the press's hopper. The cardanically mounted screw conveyor transports a defined amount of material into the press chamber. The pressing process then occurs under pressure. The use of die technology in the TH 1500 press allows for better compaction and volume reduction compared to a press pliers. The briquetting process recovers valuable coolants, residual oils, and emulsions, which can then be reintroduced into the cooling or lubrication cycle. De Rooy returns up to 300 liters of coolants to the cycle daily. The finished briquettes are regularly picked up by a recycling company for reprocessing. There, they are melted down and processed back into recycled metal.

"Thanks to the WEIMA press, we optimize storage. The pressed briquettes take up much less space than the loose aluminum chips. We can make internal and external transport much more efficient, and further processing is more cost-effective for us. We save resources and operate sustainably," says Jos Schouten.

De Rooy has equipped the WEIMA machines with additional sensors to ensure continuous production flow. The machines are networked and can communicate independently. The TH 1500 is equipped with all common interfaces to ensure quick integration into new or existing production lines.

For this reason, De Rooy is considering the acquisition of an additional briquetting press from WEIMA. "Given the rapid accumulation of aluminum chips at our milling machines, we need another solution. We can bring the chips to the existing press, but we want to minimize internal transport. Moreover, it's important not to mix the different coolants. A new press would further increase the efficiency of our waste management," explains Jos Schouten, Production Manager.