Maximum efficiency in aluminium production RUF briquetting systems increase the value of aluminium chips at Uponor Rohrsysteme GmbH

This “turbo workcycling” involves cutting operations that waste nearly 80% of the quality aluminium (AlMg4.5Mn0.7). All in all, about 125 tonnes of oily, long continuous chips are left over every year from the approx 160 tonnes of aluminium input stock. It became clear to the production managers and the employees that they had to find a practicable solution for this waste quantity, and soon. Accordingly, the then head of production formed a project group to tackle this issue.

The object was to reduce the chip volume and to extract the oily liquid from the chips, which would otherwise have been treated as special waste since no foundry accepts wet input stock. The most promising solutions were offered by two implementations. The first involved a combined crusher and centrifuge, the other a high quality briquetting system. Ultimately, only the one proved to be economically feasible – the briquetting system. Production Optimiser Oppelt summed up the crucial factors: “Foundries pay virtually nothing for wet chips. On the other hand, briquettes take up far less space, and the overall costs for briquetting systems are lower.”

The Uponor project group’s continued researches soon uncovered a suitable supplier, the Zaisertshofen company RUF, leader in innovative briquetting technology. Gerald Oppelt explains: “We scoured the internet and the trade media. In addition, we asked for recommendations from our partners like Knoll Maschinenbau, our preferred specialist for filter systems. The name RUF was mentioned time and time again. Following the experience I’ve gained, I can only confirm that.” An inspection of the systems in Zaisertshofen in late 2004 and a number of test runs served to convince the Uponor delegation unreservedly, and the order was placed for a RUF 4 /3700/60x40.

Punctually on the agreed delivery date, on 2 January 2005, the RUF 4 arrived in the Uponor aluminium machining area in Hassfurt – precisely two weeks after the lathes had been commissioned. Oppelt recalled that those two weeks without briquetting press were not easy ones: “The huge volume of chips accumulating in this period took up a lot of space we didn’t have. So we were very happy when RUF delivered the machine on time and commissioned it in just half a day. Since then it has been running unattended, reliably and continuously, in three-shift mode five and, if necessary, six days a week. Ultimately and accordingly, the briquetting press paid off within just nine months.” Following this encouraging experience, Uponor purchased in 2007 an additional RUF 4, and now each automatic lathe has its own briquetting press. This has served to simplify further the production processes and raise overall productivity.

The two RUF 4 units are midsized machines that can process the most diverse metals and are ideal for compressing aluminium chips. Thanks to the screws installed in the feed hopper, the continuous chips can be supplied directly and at a high rate from the automatic lathes to the briquetting machine. There they are compressed under 300 bar generated by a 4 kW hydraulic motor and formed into rectangular briquettes under a specific pressure of 2304 kg/cm². Measuring 60 mm wide and 60 mm high, they can be handled easily. The volume of the input aluminium is reduced to as much as one twentieth, depending on the chip geometry.