Automated deburring of cross bores

Automating processes requires analysis of deburring methods, a factor often overlooked. Knoepfel AG identified this and sought a solution from HEULE Precision Tools in the production of highly complex mechanical components and cross bores.

Manufacturers depend upon external specialist partners with a high level of expertise. One of these manufacturers is Knoepfel AG from Walzenhausen in Switzerland. The 50 employee business is focused on the production of complex, high-precision mechanical components and thanks to its process-oriented approach and ‘zero error’ mindset, Knoepfel AG is not only a pioneer for series production, but also well suited to produce small batches.

In recent years, Knoepfel AG has transformed from a small workshop into a leading manufacturer in its field. The company is continuously streamlining processes and thereby improving the range of services for its customers. For this reason, Knoepfel AG invests in automation and the most up-to-date production technologies to enable reliable and cost-effective production strategies.

Such a strategy was required some time ago in the production of a wheel bearing made of high-tensile steel. A convincing machining concept was quickly presented to the customer, whereupon production of the hundreds of components per year was started. After a few months, Knoepfel AG recognised further automation potential. The workpiece has intersecting cross bores with a diameter of 7mm. Until now, the resulting burrs on the internal bore intersections were being removed manually with deburring scrapers and brushes, which was extremely time-consuming. Now, this process step is fully automated so that the high-precision components will come off the machine finished and burr-free.

Knoepfel already uses mechanical deburring tools from HEULE Precision Tools for various applications. The official representative of HEULE for the Swiss market, Eisenbart GmbH, was consulted about the feasibility of automatically deburring cross bores. Thomas Eisenbart accompanied Knoepfel AG closely during the application analysis and coordinated a visit to HEULE’s production site in Balgach, during which not only the various deburring options were presented, but also the first tests were carried out with the COFA-X tool from the X-BORES series. This tool concept is always customised by HEULE to suit the specific application requirements of the customer. It is suitable for intersecting bores with a main bore-to-cross-bore ratio of 1:1, as well as for applications with axial offset.

During tests at HEULE, it became apparent that the workpiece material itself presented the greatest challenge, as the surface hardens due to heat produced during cutting. The tests resulted in modifications to the tool, after which Knoepfel carried out further testing. The deburring results delivered a high-quality and process-stable solution. The X-BORES tool has now been fully integrated into the series production.

By eliminating the time-consuming manual deburring, up to 12 minutes are saved per workpiece, which amounts to around 280 hours per year based on a production quantity of 1,400 workpieces. The elimination of manual deburring also enables the reallocation of the employee’s skills to carry out more valuable tasks. Daniel Boehrer, CNC turning specialist at Knoepfel, is also impressed by the new solution and especially by the long blade life: “I always check the tool after about 300 parts. Most of the time, it shows that the blade is still working perfectly.”

Thomas Dietsche, Head of Production and Technology at Knoepfel, is particularly pleased with the stable and reliable process: “We no longer have to worry about burrs remaining and can focus our attention on other challenges.”