Kelzenberg scores a century

In 1999, German roller and drum manufacturer Kelzenberg became a subsidiary of Carl Krafft & Söhne and this year they are celebrating nearly 250 years of combined knowledge and experience.

It is 100 years since Kelzenberg was established, focusing its manufacturing and engineering capabilities on container construction, and in 2020 Krafft, which has its roots in engineering for the paper industry, will mark its 150th anniversary.

The two companies, both founded in Düren, in the west of Germany, evolved into manufacturing drums for panel presses and they were supply partners with some of the press manufacturers for many years.

Krafft was a long-term supplier to both Metso and Siempelkamp for their doubleband presses, while Kelzenberg collaborated with Berstorff and Bison for many years and established an exclusive supply for the Mende, or Auma, press. Kelzenberg has supplied hundreds of drums for this type of machine.

“Each press required a set of drums with one big centre heating drum, heated by thermal oil and covered with a hard overlay welding,” said general manager Michael Hess.

The largest presses installed were equipped with a 5m-diameter heating drum. It was when Bison ceased trading that Krafft took over Kelzenberg. In 2014, Krafft expanded its workshop and moved the Kelzenberg operation to the site.

“The merger between Krafft and Kelzenberg provided us with the biggest accumulation of roll-making knowledge, especially for the big drums for particleboard presses, whether it’s a continuous press or the Mende press,” said Mr Hess.

The panel market remains an important customer base for Kelzenberg. It manufactures the 5.5m-diameter drums for calender presses made by Binos and has a healthy business providing replacement and reconditioned rollers and drums all over the world.

“The first Auma presses were built in the 1970s and a lot of them are still working,” said Mr Hess.

The central heating drum in these presses, which is subject to considerable force and speed, can run for 20-30 years, but when wear and fatigue take their toll, this is where Kelzenberg steps in.

“If the drum is still mechanically sound we can service the drum’s surface,” said Mr Hess. Working on the customer’s site,Kelzenberg re-welds the hard, top layer of the drum and another company it engages provides the grinding service required to produce a smooth surface and correct the geometry of the roll.

During its 100-year history, Kelzenberg has developed the design of the drums as experience has allowed a better understanding of the loads and forces applied by the presses. It has also been able to harness the knowledge gathered from a range of industries and applications.

“We are a roller specialist but we are working in many different applications and this helps us to transfer knowledge between customer industries,” said Mr Hess.

Focusing on replacement parts has also enabled the company to fine-tune the design.

“When you work for an OEM their design is influenced not only by quality, but also cost. As we concentrate on spare parts, which are not as price sensitive, we can provide the best possible technical solution,” he said. Kelzenberg has competitors, but what sets it apart, Mr Hess said, is its craftsmanship. “We believe our design is the most sophisticated because we use our wide experience in designing and building the drums,” he said.

Finding suitably qualified people to maintain this standard is not always easy, so Kelzenberg runs its own training programme. Nearly 12% of its 130 employees are trainees who are undertaking a three-year training programme.

As Kelzenberg marks its centenary, parent company Krafft is taking it into the next stage of expansion. After extending the workshop facilities in 2014, later this year Krafft will begin construction of another hall to accommodate the growing business.

“We are expanding our capacities step by step as turnover increases,” said Mr Hess.