#burrfree Production Parts Straight Out of the Machine with Ball Cutter and Ceramic Fiber Brushes
Flexibility is just one of the hallmarks of contract manufacturer Schwab CNC, albeit the most important one. The family-run company, with a total of 24 employees, is especially in demand when rapid action is required while maintaining the highest precision. Schwab CNC can provide consulting support already during the planning and design phase, defining the subsequent production processes based on customer specifications. In doing so, all required standards, for example for the automotive industry, are met. By focusing on series production combined with high flexibility, the company can produce up to 200,000 units of a single component annually , as well as handle small series and even produce prototypes.
The specialist in magnesium and aluminum castings, using sand or die casting processes, primarily supplies customers from the automotive and electronics sectors, but has also expanded into the growing e-mobility and photovoltaic markets. The often highly complex parts, which frequently have stringent quality requirements, must still be produced cost-effectively, which involves reducing all manual operations. This is essential for maintaining consistent quality and high machine utilization even across large series production.
Challenging Deburring Requirement Demands Innovative Tooling Solutions
For an actuator housing (steering gear housing) made of magnesium for the automotive sector, automated machine deburring is a customer requirement. With a volume of 200,000 pieces per year, this is no easy task, as the necessary tooling solutions had not yet been used at Schwab CNC. The main challenge was deburring an almost elliptical recess, as well as deburring several elongated holes within the main bore, which could not be accomplished with conventional deburring tools. Only after contacting KEMPF and field representative Dominik Wiesner a complete deburring strategy was developed with two different tooling solutions, each available in two versions.
To machine the complex internal contours, Dominik Messaros opted for the innovative Back-Burr Cutter & Path deburring system. Unlike deburring tools that perform linear movements relative to the cross-hole while rotating, this deburring system uses a more effective method—contour-parallel deburring along the edge or contour to be machined. Only through this synergistic system, consisting of a spiral-fluted, high-temperature-resistant ball end mill and a specially generated NC dataset for the application, can bore intersections, thread exits, and even the most complex contours be deburred with process reliability.
Using an application-specific NC dataset, the cutter precisely follows the contour of the component to be deburred, safely and completely removing burrs, including on the backside of bores. Notably, the system generates a defined contour that can be reproduced consistently across all parts to be machined, ensuring consistent deburring quality. A key advantage of the Back-Burr Cutter & Path deburring system is the NC dataset, which simultaneously shifts the cutter’s contact point with the component during machining, preventing localized wear and significantly extending tool life. For the magnesium actuator housing, this means approximately 20,000 parts can be machined with a single ball end mill.
The upper flange surface and all contours on the underside are additionally deburred with two ceramic fiber brushes made of high-performance ceramic. Each fiber rod of the brushes consists of about 1,000 bonded fibers, which are approximately 80% ceramic, providing highly effective abrasive performance. The self-sharpening cutting edges of the ceramic fibers ensure constant grinding performance and thus uniform burr removal on the component. A beneficial side effect: due to the unique properties of these ceramic fiber brushes, an average wear of only 0.0005 mm per component enables a tool life of more than 100,000 machining cycles. To ensure consistent deburring performance, Schwab CNC uses parameter-based brush length compensation. The brush length automatically reduces after each program cycle until the preset wear limit is reached. For this actuator housing (steering gear housing), the operator only needs to readjust the brush after 20,000 components.
Continuous Automated Deburring Directly in the Machine
By implementing KEMPF’s machine deburring solutions, not only was the customer’s requirement met, but the labor needed to produce the magnesium components was reduced by 50%. The subsequent manual deburring with inconsistent quality was completely eliminated, enabling fully automated production on two machines with robotic loading. The cycle time per part increased by only five seconds—a top value for absolutely process-reliable complete deburring of the component and a worthwhile investment for Schwab CNC, resulting in better, consistent quality and fewer complaints.
Machine deburring with a ceramic fiber brush with a diameter of 40 mm – this traces the entire component edge on the underside within seconds and removes the burrs completely. Continuous robot loading ensures nearly 100% machine utilization. To guarantee consistent grinding performance across all parts, the brush overhang can be easily adjusted via a set screw on the aluminum sleeve, or a compensating holder can be used for automated wear compensation. Schwab CNC relies on a tool length adjustment of 0.0005 to 0.003 mm via R-parameter programming of the brush for this application.
Close-up of the top side of the actuator housing: The magnesium cast component features numerous bores and resulting contours that require deburring. Due to this complexity, much of the deburring was initially done manually at the start of production. Only with the use of the Back-Burr Cutter & Path deburring system was it possible to machine and fully deburr the elongated holes using the ball cutter type BXC-33-A and the large, nearly elliptical internal contour with type BXC-48-A. The flange surface with various (threaded) bores is also deburred burr-free here using a ceramic fiber brush with a diameter of 15 mm.