Radiusing of tooling components with the drag finishing technology.
To date, the voestalpine Rotec GmbH, a global leader in the manufacture of precision steel pipes and tubes, has been using a manual process to place a radius on its stamping tools. Within the framework of its continuous process optimization program, the company replaced this manual operation with an automated Rösler drag finishing system R 4/700 SF. With the single piece dry drag finishing process, the usable life of the stamping tools can be at least doubled. For some tools, the uptime can even be increased by a factor of ten. For this reason, the return on investment period (ROI) is well below two years.
With eleven manufacturing locations in Europe, North-America and Asia the voestalpine Rotec is a globally operating company that is specialized in the manufacture, refinement and marketing of precision steel pipes and tubes. Since the company belongs to the internationally operating steel and technology corporation voestalpine, the customers have direct access to comprehensive know-how ranging from steel liquefication to the complete pipes and tubes. The development of innovative products and manufacturing technologies takes place in four divisions. Within the corporate structure the voestalpine Rotec, headquartered in Krieglach, Austria, belongs to the metal forming division. At this location the company manufactures primarily belt tensioning tubes for the automobile industry. The complex manufacturing equipment for making pipe and tube components is also designed and built at the same location. Hannes Winkler, assistant to the plant manager at voestalpine Rotec and responsible for process optimization, explains: „To be able to make our products at internationally competitive costs, our company is utilizing continuous improvement processes.”
Cost reduction by increasing the usable life of tooling
Even before wear became visible, stamping tools like arbors and die plates had to be replaced because of minor fracturing at the edges. Frequently the edges were reworked by hand. But this did seldom extend the usable life of the tools. With around 50 million manufactured components per year tooling supply was a significant cost factor. Therefore, it was not surprising that the process optimization specialist was looking for an automated, repeatable edge radiusing process for prolonging the service life of the tooling.
Cost-efficient dry processing in a drag finisher
Edge radiusing of the tools is an ideal application for the drag finishing technology. This unique mass finishing system allows the precise, targeted surface finishing of high-value, complex workpieces. Exactly defined process parameters guarantee absolutely repeatable finishing results. “From my previous occupation at a supplier of motorsport components, I knew that Rösler Oberflächentechnik builds such equipment. That is why I contacted Rösler first. Of course, we also contacted other suppliers of mass finishing equipment and asked them to run processing trials for us”, continues Hannes Winkler. In the end the customer chose the R 4/700 SF system because Rösler was the only supplier, who could offer a dry finishing process for the tools. Hannes Winkler adds: „The dry solution eliminated the process water cleaning system required with the wet processing solution. This reduced not only the capital expenditure but also resulted in lower operating costs. Of course, the quality and long service life, as well as the high availability of the Rösler equipment, also played an important role in our decision.”
Automated finishing that is perfectly adapted to different tools
At the heart of the compact, plug-and-play drag finisher is a carousel equipped with four rotary spindles, each spindle allowing the mounting of three workpieces. The carousel and the rotary spindles are outfitted with separate drive motors allowing the setting of totally different rotary speeds for the carousel and spindles. The processing bowl is filled with processing media, which in this particular application consists of crushed walnut shells and aluminum oxide. A vibratory motor mounted below the processing bowl ensures the optimum mixing of the processing media. Required bowl changes can be quickly carried out with a forklift truck.
For the actual process, the tools to be finished are manually mounted to specially designed workpiece fixtures, which in turn are attached to the spindles equipped with quick-connect couplings. To facilitate this operation, the operator moves the spindles to the load/unload station with the touch of a button. This allows quick, ergonomic and simple loading/unloading of the workpieces.
Once the respective processing program, stored in the programmable system controls, has started, the carousel with the spindles is lowered so that the rotating spindles are immersed in the processing media. Carousel and spindles are moving clock- and counterclockwise at the defined rotary speeds. At the midpoint of the processing cycle – depending on the tools to be finished, the total finishing time varies between 15 and 45 minutes – the rotary direction is usually changed. This guarantees an even radiusing of the tool edges on all sides.
Continuously growing workpiece spectrum shortens the amortization period
Initially, it was planned to use the drag finisher for five frequently used tool types. Hannes Winkler reports: „The new mechanical drag finishing system produced such good results that the usable life of these components could be practically doubled. And in some instances, it could even be increased by a factor of ten. Since commissioning the drag finisher about six months ago, we have increased the spectrum of workpieces to be finished mechanically to around 20 different tool types. This helped reduce the amortization period to well below two years. By continuously adding additional workpieces, the amortization time will decline even further”. This positive experience led the voestalpine group of companies to list Rösler as the exclusive supplier for this particular finishing application.
Besides the mechanical edge radiusing of additional tool types, the process optimization specialist is also considering a polishing application. Hannes Winkler concludes: „At the moment we are conducting processing trials. If the results are as we expect, we will purchase a second processing bowl with the required processing media. A key advantage of the Rösler drag finisher is that processing bowls can be easily exchanged allowing us to quickly switch from one application to another”.
For over 80 years the privately owned Rösler Oberflächentechnik GmbH has been actively engaged in the field of surface preparation and surface finishing. As a global market leader, we offer a comprehensive portfolio of equipment, consumables and services around the mass finishing and shot blasting technologies for a wide spectrum of different industries. Our range of about 15,000 consumables, developed in test centers 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.
For more information please go to www.rosler.com
Image courtesy: Rösler Oberflächentechnik GmbH
Picture: IMG R 4/700 SF.jpg
Underline: The compact, universally usable drag finisher R 4/700 SF is equipped with a carousel with four rotating spindles. Each spindle holds three workpieces. Separate rotary drives of carousel and spindles allow the individual, entirely independent adjustment of their rotary speeds. For the ergonomic, simple and quick loading of the spindles the carousel can be moved to the load/unload station by the push of a button.
Picture: IMG Schleppfinisher workbowl.jpg
Underline: The processing bowl of the plug-and-play drag finisher can be easily exchanged with a forklift truck. This allows quickly switching from one application to another without having to replace the processing media