Improved productivity, increased production capacity, better quality, and lower costs—a leading garden tool manufacturer tasked Rosler with developing a new mass finishing system to improve the deburring and polishing of garden shear knives.
Rosler provided a solution in the form of a tailor-made Keramo-Finish® process carried out within a double-batch centrifugal disc finishing machine. Known as the FKS 35.1 A2-So, the system includes fully automatic work piece handling and a two-stage process that deburrs and polishes stamped and laser-cut knives. Work pieces are subsequently dried in an energy-efficient rotary dryer and prepared for the next manufacturing step.
For more than 60 years, the Gardena division of Husqvarna Group has developed a variety of gardening products and tools. The company’s broad product range includes innovative systems for irrigation, soil cultivation, and lawn, tree, and shrub care. Gardena products are used in more than 80 countries worldwide.
To ensure easy and simple handling, produce excellent cutting performance, and guarantee long service life, the Gardena’s shear components are produced with state-of-the-art manufacturing technologies. Stamping or laser cutting of the upper and lower knives followed by surface finishing is an important step.
Previously, the lower knives required two separate finishing operations: one in a rotary vibrator and one in a centrifugal disc finishing machine. Since Rosler originally provided systems for the two separate operations, Gardena trusted Rosler to develop a combined solution with upgraded manufacturing capabilities and increased automation. In streamlining the mass finishing process, Gardena sought to optimize its process, improve productivity, increase capacity, and reduce operating costs.
Keeping subsequent manufacturing steps in mind, engineers ran a series of trials with various processing media and different parameters in one of Rosler’s Customer Experience Centers.
A Keramo-Finish® process in a centrifugal disc finishing machine produced the best results. The specific process includes the use of a ceramic media with minimal abrasive characteristics in combination with a grinding and polishing paste and a cleaning compound with a distinct brightening effect. Most importantly, the new process allows the deburring and polishing of all knives with a single machine.
The rotary vibrator was no longer required, and the work piece handling was simplified. Moreover, depending on the work piece type, the new Keramo-Finish® process has reduced processing times significantly and now allows for bigger work piece batches.
These improvements have helped reduce operational costs by approximately 10% while delivering improved finishing results.
The new double batch centrifugal disc finishing machine was perfectly integrated into the manufacturing flow at Gardena. Work piece specific processing programs stored in a PLC controller allow targeted finishing of the various knife types.
After stamping and laser cutting, the work pieces are collected in perforated metal bins. An operator utilizes a swing crane to dump the raw knife components into a loading device that transfers them into a vibratory feed hopper. Once the respective finishing program has been manually selected, the hopper automatically feeds a work piece batch into the work bowl for processing.
Following the preset finishing time, the work bowl gently dumps the mix of finished work pieces and media onto a vibratory hopper. The mix then passes through a vibratory separation unit where a screen separates work pieces from media. The media mix itself is further screened to discharge undersized media that is no longer suitable for the finishing process and guarantee a continuous high process stability.
While usable media is returned to the work bowl, the finished knife blanks are transferred to a drying station filled with a maize-cellulose product. The rotary dryer RT 550 Euro-DH is equipped with an innovative new direct heating system that guarantees not only fast, reliable, and spot-free drying of the work pieces but also produces energy savings of up to 40% compared to conventional rotary dryers.
After completion of the drying cycle, knives are transferred to another vibratory hopper that loads them into small transport carriers made from plastic.
A fully automatic Z 1000 centrifuge cleans the process water for re-use in the finishing process. This recycling helps save valuable resources by drastically reducing water consumption and promoting sustainable and efficient operation of the new mass finishing system.
The automated aspects of Gardena’s new system went beyond improved efficiency and capabilities to provide an additional advantage in the reduced need for manual labor. Like many employers, Gardena has faced increasing competition for manpower.
The use of work piece handling systems, conveyor belts, and robots have helped bridge the gap in human resources and maintain production rates. Additionally, in the world of manufacturing, this mitigation of human intervention offers even greater and more measurable efficiencies.
The Rosler Way
Decades of experience and ability to design, service, and maintain machines as well as the consumables and accessories to get the finish you require make Rosler a well-rounded surface finishing expert. Contact us to discuss your mass finishing needs.