Everllence compresses the cast chips produced during manufacturing into compact briquettes, which are then remelted again in its own foundry. In doing so, the Augsburg based company, known as MAN Energy Solutions until early June, closes the material cycle and reduces costs. Three briquetting systems from RUF are in operation, processing well over a thousand tonnes of chips per year. RUF is now upgrading one of the briquetting presses to expand production.

Everllence’s headquarters and main plant are located in Augsburg, where more than 4,000 employees produce large four-stroke engines for shipping and power generation, as well as turbochargers, among other components. The heaviest product manufactured here is an 18-cylinder unit with turbocharging, which produces 21,600 kilowatts and weighs 270 tonnes. The starting point for production is the iron foundry, which has been in operation since 1844. Around 300 employees produce engine parts ranging from 300 kg to 120 tonnes – using cast iron with lamellar graphite GJL (grey cast iron) and cast iron with nodular graphite GJS (spheroidal graphite cast iron). The foundry also produces for Everllence sites in Saint-Nazaire, France, and Aurangabad, India, as well as to external customers. 

Sustainability is very important to Everllence.

The company uses up to 90 per cent secondary raw materials and operates the foundry mainly with green electricity. In addition, the company closes the material cycle directly in its operations by melting down cast chips from machining for reuse. Three RUF briquette presses play a central role in this process. 

High handling effort due to loose and wet chips

The closed material cycle for production waste has a long tradition at Everllence. However, before the introduction of briquetting technology, it caused considerable difficulties. ‘Handling the wet chips was always a major problem for us,’ explains Erwin Schuster, who manages cylinder block production. This is because loose and wet chips – still containing cooling lubricants – caused significant contamination during the relatively long transport from the machining shop to the foundry. Additionally, as Schuster explains, the foundry needs the input material to be as dry as possible in order to be able to melt it down efficiently and safely. 

25 years of reliable operation

The production planners at Everllence, then still operating under the name MAN Energy Solutions, found the solution to the problem with the medium-sized plant manufacturer RUF. The Zaisertshofen-based company delivered the first briquette press to Augsburg back in 1999. The RB 15/3000/80 system is still working reliably in cylinder head production today and produces around 100 tonnes of briquettes per month. The numbers in the model designation stands for an electrical output of 15 kW, a specific pressing pressure of up to 3000 kg/cm² and a briquette diameter of 80 mm.

Under high pressure, the RUF systems press metal chips – or other materials – fully automatically into compact briquettes that are easy to handle and take up much less volume than loose chips. It is important to note that highly compacted chip briquettes can be melted down just as easily as broken castings made from solid material.

Briquettes can be melted down without any problems

In metal processing it is extremely important that cooling lubricants adhering to the chips are pressed out almost completely. As a result, the briquettes are largely dry. At the same time, the extracted coolant can be collected and often reused – with or without filtration.

The closed material cycle and the use of briquetting offer several advantages for melting down production residues in the foundry. Tobias Rist, plant engineer in the melting shop, explains: “We know the composition of the briquettes very precisely, as they are made from the cast iron we produce ourselves. This means we can make excellent use of them to optimise charging.” 

Because the briquettes are largely free of cooling lubricant residues, there is significantly less smoke generated than when melting down relatively wet chips. Therefore, no additional measures are required on the exhaust gas side for extraction or cleaning. The briquettes usually come out of the presses with a residual moisture content of one to three per cent. After a few days of storage, this is reduced even further as the water content evaporates quickly.

Briquette use in mains frequency and medium frequency furnaces

‘While loose swarf caused melting problems, swarf briquettes can be used in the same way as other scrap,’ explains Rist. 

A special feature of the foundry at Everllence is that melting takes place in both the mains frequency furnace and the medium frequency furnace. While the medium-frequency furnace is charged into the completely empty furnace, it is extremely important in the case of the mains frequency furnace that the minimally moist briquettes are not charged directly into the molten cast iron. However, this is easy to do, says Rist: “Firstly, cast iron scrap and other scrap is charged into the molten iron. The proportion of chip briquettes that was previously determined in the charging calculation is then placed on top of this – without coming into contact with the molten iron.” 

The heat from the hot melt below dries the briquettes completely. The highly compacted briquettes integrate perfectly and melt completely with a high metal yield. There are no negative effects in terms of melting times, exhaust gas development, refractory material or power consumption when using the briquettes, but there is a considerable cost advantage.

Briquette use in mains frequency and medium frequency furnaces

The closed material cycle with short transport distances is not only environmentally friendly and beneficial from a production standpoint, it also offers clear economic advantages. The bottom line is that the use of briquettes is significantly cheaper than buying in scrap iron. Feedback from various RUF customers indicates a cost advantage of around 120 euros per tonne.

Following the successful performance of the first press, Everllence installed two additional RUF briquetting systems in 2005 and 2008, this time for cylinder crankcase production. One of the systems, the RUF RB 15/3700/100, processes around 20 tonnes of chips per month from three five-axis machining centres. The second, a RUF 18.5/3700/100, is used with two large gantry portal milling machines that handle castings weighing up to 100 tonnes.

The two gantry milling machines produce around 40 tonnes of casting chips per month. These are transported underground to the briquette press by hinged belt conveyors. An ascending conveyor then carries the material into the chip hopper of the press, which can produce around 800 kg of briquettes per hour. With a diameter of 100 mm, the briquettes are approximately 80 mm long and weigh around 3.5 kg.

Fully automatic operation – hardly any maintenance required

The presses from RUF operate fully automatically and are designed for unmanned 24/7 operation. They start and stop independently, depending on whether sufficient material is present in the chip hopper or once processing is complete. Only the containers in which the finished briquettes are collected need to be replaced when they are full. The operation is controlled in such a way that briquettes of spheroidal graphite cast iron are collected separately from other types of cast iron in clearly labelled containers. This allows them to be melted down in the correct alloy. 

The maintenance effort is also extremely low. ‘The systems run extremely reliably; our maintenance department only has to replace seals or install small spare parts sporadically,’ reports machine and system planner Ralph Fritz.

Challenge: highly fluctuating quantities of chips

One major challenge with regard to briquetting is the highly fluctuating quantities of chips that are produced during the manufacture of the huge cylinder crankcases on the portal milling machines. Although the chip conveyors on the milling machines run continuously, the process is far from steady. For instance, machining an 88-tonne cast part can produce around 14 tonnes of chips—many of which initially remain on the worktable or within the component. These are only shoveled onto the conveyor belts once the machining process is complete, resulting in large volumes of chips being delivered all at once. To accommodate these peak loads, the experts at RUF and Everllence decided back in 2008 to equip the briquetting press with an upstream hopper holding approximately 1.5 m³ and designed the system to handle a peak capacity of 800 kg per hour.

Existing press upgraded for higher chip volumes

The Augsburg-based company is now expanding its production with a third gantry portal milling machine, which will increase the chip volume to 60 tonnes per month and require the briquetting system to be upgraded. 

A key question for those responsible at Everllence was whether it made more sense to continue using the press, which is now almost 17 years old, or to install a new one. The experts from RUF made a clear recommendation to continue using the existing system, as it is still in good condition. Ralph Fritz explains: “Our maintenance engineers also confirmed that the press is still working reliably. It will now undergo major maintenance. And we expect to be able to operate it for many years to come without any problems.” This confirms the longevity of the very compact design of the RUF presses, which often run for decades without any problems due to the high-quality standards in the manufacturing process. Upgrading the system for the growing quantities of chips is nevertheless a complex task. “Due to the limited space available, the implementation is challenging. But RUF was able to solve all the technical challenges in advance,” emphasises Fritz, praising the excellent communication during the planning phase.

As part of the upgrade, RUF installed a chip hopper one-third larger than the previous version. Additionally, new ascending and emergency discharge conveyors were integrated into the system—an achievement made even more impressive given the limited space available.

The expansion work on the RUF system will also not disrupt operations at Everllence. This is because the experts from RUF always complete such work reliably within a few days. Therefore, planning can be made to ensure that no extremely large quantities of chips are produced during this time without any problems.