E-Archive

Cover Page

in Vol. 22 - July Issue - Year 2021

Optimized Finishing Process at Gardena Increases Productivity and Lowers Costs

The package consists of a double-batch centrifugal disk-finishing machine with fully automatic workpiece handling, a rotary dryer and a fully automatic centrifuge for cleaning and recycling of the process water

The stamped and laser-cut knives are deburred and polished in a two-stage process in order to create optimal conditions for the next manufacturing step and to guarantee a long service life

The best results were achieved with a Keramo-Finish process in a centrifugal disk finishing machine. This 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. Moreover, depending on the work piece type, the new Keramo-Finish process reduces the processing times by 25 % to over 100 %

The finished knife blanks are transferred to the drying station filled with a maize-cellulose product. The rotary dryer RT 550 Euro-DH is equipped with an innovative new heating system that guarantees not only fast, reliable and spot-free drying of the workpieces but also produces energy savings of up to 40 %

In the Spotlight

For over 80 years, the privately owned Rösler Oberflächentechnik GmbH has been actively engaged in the field of surface preparation and surface finishing. As global market leader, we offer a comprehensive portfolio of equipment, consumables and services around mass-finishing and shot-blasting technologies for a wide spectrum of different industries. Our range of about 15,000 consumables, developed in our Customer Experience Center located all over the world, specifically serves our customers for resolving their individual finishing needs. Under the brand name AM Solutions, we offer numerous equipment solutions and services in the area of additive manufacturing/3D printing. Last-but-not-least, as our central training center, the Rösler Academy offers practical, hands-on seminars to the subjects of mass finishing and shot blasting, lean management and additive manufacturing. Besides the German manufacturing locations in Untermerzbach/Memmelsdorf and Bad Staffelstein/Hausen, the Rösler group has a global network of 15 manufacturing/sales branches and 150 sales agents.

Improved productivity, increased production capacity, better quality and lower costs. These were the demands of a leading garden tool manufacturer when it invested in a new mass-finishing system for deburring and polishing of garden shear knives. Rösler met this challenge with a tailormade Keramo-Finish process that is run in a double batch centrifugal disk finishing machine FKS 35.1 A2-So with fully automatic workpiece handling. In a two-stage process, the stamped and laser-cut knives are deburred and polished in the FKS finishing machine. Subsequently they are dried in an energy-efficient rotary dryer and prepared for the next manufacturing step.

For more than 60 years, Gardena, a brand of the Husqvarna Group, has been offering everything ardent gardeners need. The broad product range includes innovative systems for irrigation, lawn, tree and shrub care, as well as soil cultivation. Gardena products are used in more than 80 countries all around the world.

A transformation to ultra-modern equipment and process technologies

To ensure easy and simple handling, excellent cutting performance and to guarantee a long service life, the shear components are produced with state-of-the-art manufacturing technologies. Important steps are the stamping or laser cutting of the upper and lower knives followed by a deburring and polishing process in mass-finishing equipment. Previously, the lower knife required two separate finishing operations, one in a rotary vibrator and one in a centrifugal disk-finishing machine.

To combine these two operations into one and adapt them to the latest manufacturing requirements, the existing mass-finishing equipment, used over many years, was replaced. Gardena chose a finishing solution from the Rösler Oberflächentechnik GmbH, who had already supplied the machinery used to date. By investing in new equipment, the customer was looking for a comprehensive optimization of the finishing process that improved not only productivity and offered a higher capacity but also resulted in lower costs.

A finishing system that produces shorter cycle times and improved operational efficiency

Based on the surface finishes of the steel knives required for the next manufacturing steps, the Rösler process engineers ran a series of processing trials in their test lab with various processing media and different process parameters. The best results were achieved with a Keramo-Finish process in a centrifugal disk-finishing machine. This included 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. The new process allowed the deburring and polishing of all knives in one single machine, the rotary vibrator was no longer required, and the workpiece handling was simplified. Moreover, depending on the workpiece type, the new Keramo-Finish process reduced the processing times by 25 % to over 100 % and also allowed for bigger work-piece batches. This helped to reduce the operational costs by around 10 % with, at the same time, greatly improved finishing results.

Fully automatic processing in a double batch system

The new double-batch centrifugal disk-finishing machine was perfectly integrated into the manufacturing flow at Gardena. Workpiece specific processing programs stored in the PLC controller allowed for targeted finishing of the various knife types.

After stamping and laser cutting respectively, the work-pieces are collected in perforated metal bins. The operator utilizes a swing crane to dump the raw knife components into a loading device that transfers them into a vibratory feed hopper. After the respective finishing program has been manually selected, the hopper automatically feeds a workpiece batch into the work bowl for processing. After the preset finishing time, the work bowl gently dumps the mix of finished workpieces and media onto a vibratory hopper from where the mix is transferred to a vibratory separation unit. There, with a precisely sized hole screen, the media and finished workpieces are separated from each other. At the same time, a special undersized media screen is discharging media that is no longer suitable for the finishing process. This guarantees continuous high process stability.

While the media is returned into the work bowl, the finished knife blanks are transferred to the drying station filled with a maize-cellulose product. The rotary dryer RT 550 Euro-DH is equipped with an innovative new heating system that guarantees not only fast, reliable and spot-free drying of the workpieces but also produces energy savings of up to 40 % compared to conventional rotary dryers. After completion of the drying cycle, the knives are transferred to another vibratory hopper that loads them into waiting small transport carriers made from plastic.

A fully automatic Z 1000 centrifuge cleans the process water and recycles it back to the mass finishing system for re-use in the finishing process. This helps save valuable resources. The drastically reduced water consumption, along with the innovative finishing solution and well-planned process controls ensure a sustainable and efficient operation of the new mass-finishing system.

For Information:

Rösler Oberf lächentechnik GmbH

Vorstadt 1, 96190 Untermerzbach, Germany

Contact: Mr. Daniel Hund

Tel. +49.9533.924-802, Fax +49.9533.924-300

E-mail: d.hund@rosler.com

www.rosler.com