When it comes to innovative tool developments and the optimization of machining processes, Walter AG, with its mission to provide groundbreaking solutions to the machining industry, is an absolute technological leader. To maintain its leadership the company is continuously investing in the latest manufacturing equipment. This includes the most recent investment in a Rösler drag finishing system with robotic work piece loading & unloading that allows fully automatic deburring of various tool bodies and offers a high degree of process stability and production flexibility.
Internationally recognized as an innovation driven company, Walter AG, founded in 1919, is a global leading supplier of precision tools for the metal processing industry. The company, headquartered in Tübingen, Germany, offers top-notch quality under the labels; Walter, Walter Titex, Walter Prototyp, Walter Valenite and Walter Multiply. The driving force behind the Walter corporate philosophy is “competence in engineering”. The impressive range of 45,000 precision tools is complemented by comprehensive customer consultation and excellent after sales service. This approach offers the numerous Walter customers in such diverse industries as aerospace, automotive, engine manufacturing, energy and railroad significant advantages with regard to performance, productivity and process stability.
Utilization of innovative technologies for optimizing the manufacturing processes
Of course, this approach requires investing in the latest technologies that become available in the market. Dr. Ing. David Boehnke, manager for technology R & D at Walter explains: “We are constantly searching for new ground-breaking manufacturing solutions. And we prefer partners who take responsibility in perfecting such developments and are willing to adapt them to our technical requirements. The Rösler drag finishing machine R 6/1000 SF-Auto with robotic part loading & unloading represents such an innovative development. This system allows the fully automatic deburring of tool bodies made from various types of treated tool steel, which later on are completed with hard metal components for milling, turning, drilling and thread cutting.
Not simply a standalone machine - but a complete solution
David Boehnke continues: “The fact that Rösler could supply the processing machine and the automation modules as well as all the required processing media, was a key factor in our decision. In other words: Rösler offered the complete process package”. The system, completely custom engineered for Walter, consists of two interlinked drag finishers with automatic robotic loading and unloading of the work pieces to and from the six (6) rotary spindles. The asymmetric assignment of work pieces to the spindles, which could potentially damage the machine, is prevented by a pre-defined loading sequence. The drag finishing system is integrated into the higher-level production planning system (master control). The slow wearing plastic grinding media and the compounds are also sourced from Rösler and have been precisely adapted to the application at Walter. The drag finishing system is equipped with an automatic cleaning centrifuge allowing the recycling of the process water. Adaptability to a broad work piece spectrum The drag finishers allow the processing of tool bodies with diameters of up to 160 mm (6.3”) and lengths of 350 mm (13.8”). This size range covers a large portion of the Walter production program. Work piece specific processing programs with parameters like rotational direction and speed of the spindles, immersion depth and cycle times are stored in the master controls. “We ran numerous processing trials in the Rösler demonstration lab and at our plant and, together with the Rösler process engineers, adapted the drag finishers to our manufacturing process. Rösler was exemplary in implementing our ideas and technical requirement in the final equipment concept. The whole project has been characterized by a high degree of cooperation”, reports David Boehnke. The concept foresees the integration of a third drag finisher offering Walter the option to process further work piece types with a drag finishing system.
Fully automatic operation ensures high productivity and process stability
For the deburring process itself batches of tool bodies are staged at the drag finishers in customer specific work piece carriers with push carts. A challenge was the precise positioning of the work pieces with a tolerance of 1/10 mm required for robotic handling. This was resolved by the joint development of a special loading concept incorporating the modeling of enveloping surfaces and establishment of load patterns.
The robot work area, shielded by a protective fence with access doors, provides space for four (4) push carts. Once the carts are placed in their pre-defined position, the operator keys the respective enveloping surface model and the quantity of work pieces into the operating panel. The master control automatically selects the respective work piece program, calculates the number of processing cycles and assigns the work pieces according to the pre-defined loading logic. The precise positioning of the rotating spindles is handled by the drag finisher controls. As soon as the door of the protective fence is closed, the robot starts loading the spindles with the raw tooling bodies.
The drag finishing process ensures that all surface areas of the work pieces are exposed to the same processing intensity in the bed of grinding media. The result is a highly effective and gentle deburring of even the most complex tool bodies. An initiator continuously monitors the pneumatic locking of the tool bodies to the spindles. In case a work piece should be inadequately locked to the spindle and fall down, the finishing process is automatically stopped, thus preventing any damage to the work pieces.
After completion of the deburring cycle the robot removes one finished tool body at a time and – depending on the program – exposes it to the cleaning station located near the drag finisher, where residual media pieces, still adhering to the finished tool bodies are removed with a mix of air, water and compound.
To maintain a homogeneous media mix – an essential condition for high process stability – the drag finishers are equipped with an undersize media classification system, which continuously discharges worn media. Replenishment with new media is done manually.
David Boehnke concludes: “In this project Rösler proved to be an innovative supplier of complete finishing solutions, bringing a wealth of surface finishing knowhow to the table as well as being able and willing to adapt its systems for the benefit of its customers. Our production team has been working with the drag finishing system since May 2015, and the results to date have been such that we intend to continue our cooperation with Rösler and expand it”.
As supplier of complete finishing solutions Rösler Oberflächentechnik GmbH is global leader in the field of mass finishing and shot blasting equipment, painting and preservation lines as well as consumables for the surface finishing (deburring, descaling, de-sanding, polishing, surface grinding,….) of work pieces made from metals and other materials. Headquartered in Germany with plants in Untermerzbach/Memmelsdorf and Bad Staffelstein/Hausen, the company also maintains sales and manufacturing branches in Great Britain, France, Italy, Netherlands Belgium, Austria, Switzerland, Spain, Rumania, Russia, Serbia, Brazil, South-Africa, India, China and USA.