Steel wheels of Kronprinz can be found on vehicles from nearly all the well-known trucks or car brands; they must, therefore, fulfil extremely strict quality requirements amid a price-sensitive market. One important step towards more efficient production was the company’s recent replacement of its spray lubrication system. technotrans technologies’ low-mist lubrication concept lowers the costs and ensures a healthy work environment for the employees.

Accuride Corporation is one of the leading suppliers of wheels for the automotive industry. The company has a global annual turnover of US$1.2bn and a workforce of approximately 5,000 across 16 locations in North America, Europe and Asia. The product portfolio includes wheels for microcars (or motorised quadricycles), heavy vehicles, tractors, construction machines and agricultural machines. As an important company within the Accuride group, Kronprinz alone provides approximately 1.6m truck wheels and more than 1.8m motor car wheels from its plant in Solingen, Germany.

The truck wheels with a particular high load-bearing capacity consist of a rim and a wheel disc. At Kronprinz, these components, which are made of rolled steel, are formed and then welded all around from the inside in modern gas metal arc welding lines. This sounds easy, but keeping an optimum balance between large quantities, high quality and a competitive price is quite a challenge.

It is a challenge that Christian Simons, Project Manager for System Planning & Design at Kronprinz, must deal with: “We regularly invest in our machinery for numerous reasons. Costs are not always our main consideration.”

The environment also benefits from a sustainable, resource-saving production. Moreover, Simons adds: “We want our employees to feel comfortable at the workplace.”

The company has optimised all three areas with a single investment: its spray lubrication system has been equipped with valves made by technotrans.

Spray lubrication without compressed air

To fulfil the company’s own exacting quality standards, and to ensure a sustainable, yet efficient, production, lubrication is a must during the forming step. It enables trouble-free forming without damage during the subsequent production steps.

However, the previous solutions could not fulfill the increasingly stringent requirements at Kronprinz any longer. It used expensive compressed air, which is not only a cost driver but also causes the oil to spread out in and around the entire system. As a result, the light barriers had to be blown free to prevent problems. The elimination of the excess oil as far as up to the neighbouring machinery was labour-intensive and blocked the personnel from completing other tasks.

“The poor air quality because of the oil mist and the compressed air consumption were arguments against our old solution,” says Simons. “In addition, the maintenance and service of the system were rather challenging. The costs continued to rise due to increasingly frequent downtimes.”

Then, several Kronprinz employees visited the technotrans stand at the EuroBLECH trade fair in Hanover. Kronprinz’s interest was piqued by a spray lubrication system without compressed air, which is already well-established in the metalworking industry and produced by a global company close to their own location.

Reinhard Skricek, Key Account Manager at technotrans, was informed about the special challenges that the wheel manufacturer was facing on a daily basis. The machine for the lubrication of wheels made in Solingen is a bespoke system based on an in-house design and specifically adapted to the special requirements of the wheel production.

A conveyor belt feeds the rim band into the machine where it is lifted. The spraying system is installed above the holding point and enables the simultaneous lubrication of the band from both sides thanks to a smaller, inner ring with outward-facing nozzles and a larger ring with an inward-facing spray lubrication system. The nozzles need to cover a precisely defined area with oil of always the same layer thickness. This takes place while the component moves upwards so that the entire process, including the lowering and exit of the lubricated band, takes fewer than 10 seconds.

Simons and his colleagues finally became convinced that they had found a solution that was indeed suitable for this type of system when they visited the technotrans headquarters in Sassenberg.

“To be honest, we were still slightly sceptical when we visited technotrans for the first time,” Simons recalls. “Being able to stand next to the system while wearing a white shirt sounded a bit too good to be true. However, the spray lubrication trials in the laboratory were really impressive.”

When he returned to Solingen, he was fully convinced of being in good hands. Further research showed Simons that a comparable technology could not be found on the market: “We finally did not take anything else into consideration in view of our requirements.”

After the order had been placed, technotrans supplied the entire spraying system, adapted the system to the installation situation and machine interfaces and trained the operating personnel. Since the start-up of the system in December 2017, it has been running 24/7 without any problems.

“The cost savings are substantial,” explains Simons. “This is due to the elimination of compressed air, the reduced oil consumption in a high two-figure range and nearly zero downtime.”

Proven technology with numerous details

The system is called technotrans spray.xact and it can be used for the spray lubrication of coils, blanks or formed parts. The spray jet is produced with a high-frequency pulsating valve with a single-product nozzle. As a result, the expensive use of compressed air for the nozzles, which leads to the formation of spray mist in conventional systems, is no longer required. Consequently, an exhaust system is not necessary either. Thanks to precise dosing and alignment, Kronprinz is able to adapt the spray cone to the round shape of the wheel band.

Therefore, technotrans is further improving the efficiency of the company by lowering the material and energy consumption. In addition, Kronprinz is optimally prepared for any requirements or legal obligations in terms of a low level of aerosol formation (oil mist) at the workplace, which will surely become even more strict in the coming years in order to reduce the environmental impact and health burden.

After just a few months, Kronprinz is absolutely convinced that it was a worthwhile investment, and not only in terms of the employees and the environment. The management is also completely on board in view of the substantial cost savings.