Wenn Werkzeugkompetenz und Beratungsqualität zusammenpassen

„Als wir die Firma 2014 gründeten, hatten wir nur eine CNC-Maschine und arbeiteten zunächst als reiner Zerspanungsdienstleister“, erinnert sich Robert Bonertz, Geschäftsführer der Bonertz Technik GmbH in Föhren. Das Unternehmen spezialisierte sich nach und nach immer stärker auf anspruchsvolle Aufgabenstellungen. Die Bonertz Technik GmbH befasst sich mit schwer zu zerspanenden Werkstoffen – speziellen Legierungen, hochfesten Stählen bis 1.100 N/mm2 oder superharten Werkstoffen mit bis zu 60 HRC. Auch Bauteile, die eine aufwendige Aufspannung erfordern, sind eine Spezialität der Bonertz Technik GmbH. Beispiele hierfür sind filigrane Strukturen, die unter hohem Zerspanungsanteil aus dem Vollen herausgearbeitet werden müssen. 

Zufriedene Kunden ermöglichen dem Unternehmen ein schnelles Wachstum. Heute stehen im Fertigungsbereich der Bonertz Technik GmbH vier moderne, hochpräzise 3- beziehungsweise 5-Achs-Fräsbearbeitungszentren. Auch die erforderliche Infrastruktur in Bereichen wie Arbeitsvorbereitung, CAD/CAM-Programmierung und Qualitätssicherung besteht.
 

„Bei vielen Bearbeitungsaufgaben ärgerten wir uns immer wieder über die Unzulänglichkeiten der verfügbaren Spanntechnik zum Aufspannen der Bauteile“, erinnert sich der Geschäftsführer Patrick Vilfan. Dies zeigte sich vor allem dann, wenn aufgrund der häufigen Produktwechsel die zu bearbeitenden Bauteile umgespannt werden mussten. Wegen der umständlichen Handhabung erforderte dies viel zu viel Zeit, die zulasten der Produktivität ging. Zudem waren die Spannmittel teils sehr unförmig und stellten für die Bearbeitung hinderliche Störkonturen dar. Ein weiterer Nachteil der gängigen Spannmittel waren die Bauhöhen, die den verfügbaren Verfahrweg in Z-Richtung begrenzten.

That is why the people responsible at Bonertz Technik GmbH decided to produce better clamping devices themselves. And not only for personal use, but also for marketing. As time went by, various versions of 5-axis clamps were developed as well as an innovative machine table as an alternative to costly zero-point clamping systems.

„Practical considerations were at the forefront of our developments”, Patrick Vilfan explained. In addition to high clamping force, an important feature was extensive modularity in the structure. Depending on the design length, the base rails are equipped with a variety of interfaces to the machine table. The clamping range can be easily extended from 10 to 1335 mm by means of spacers without any loss of clamping force. The maximum clamping force is 50 kN. The jaws, which are available in a wide range of versions, can be replaced without tools in just a few quick seconds. In practice, the systems resulted in set-up time savings of up to 90 percent. The developers at Bonertz Technik GmbH paid special attention to avoiding tool restrictions as far as possible. The clamps are therefore also available in several height variations between 130 and 210 mm.

„The contact with Bonertz Technik GmbH came about rather by chance a few years ago because they were processing components for one of our subsidiaries as a contract manufacturer“, recalled Klaus-Dieter Leick, application engineer at MAPAL. This is how he got into conversation with Bonertz when he had problems machining high-strength tool steels with trochoidal milling cutters from a competitor.

Specifically, this involved solid carbide milling cutters for cutting depths of up to 3xD with diameters of 8-14 mm, the use of which revealed that the cutting forces were considerably too high in relation to the chip volume. „The resulting overload of the spindle was already clearly audible from the machine noise and could also be seen on the controller load diagrams“, Robert Bonertz said. Klaus-Dieter Leick then provided him with some MAPAL solid carbide milling cutters to test the associated machining process. The results were convincing.
 

„The overload problems have been a thing of the past ever since thanks to the milling cutters from MAPAL. In addition, tool lives have increased significantly – by up to 30 per cent for some tasks“, Mr Bonertz is pleased to report. Since then, the managing director is familiar with the performance of the standard tools from MAPAL. For the tasks at hand, Bonertz Technik GmbH primarily requires solid carbide tools for steel machining, including milling cutters for roughing and finishing, trochoidal milling cutters, drills and deep drills as well as replaceable head systems for drilling and milling. At Bonertz Technik GmbH milling cutters are mainly used in the diameter range from 2 to 20 mm, drills in the diameter range from 1.2 to 20 mm.

„After the first successful applications we gradually used more and more tools from the MAPAL portfolio“, Mr Bonertz said. After the trochoidal milling cutters, the company tested solid carbide milling cutters for finishing its clamping systems. The tool previously used had defects on the surface caused by chatter marks. The tools from MAPAL were convincing thanks to their better cutting behaviour and the resulting surfaces.

„For us, the process reliability tools offer is a very important aspect“, Mr Bonertz explained. This is the only way that the employee can leave the equipment running after setting it up and devote himself to other tasks without having to worry about interruptions or even damage in the meantime. The tools from MAPAL are also excellent in this respect, confirms Bonertz. The managing directors are not only convinced by the technical factors – the economic aspects also play a role, of course: „We use replaceable head systems wherever possible“. Different interchangeable heads can be used with only one tool holder. A replaceable head is significantly cheaper than a comparable complete tool including tool holder. „For the reasons mentioned (quality, performance, process reliability and cost-effectiveness) around 80 percent of the solid carbide tools we use today come from MAPAL“, Mr Bonertz said.

„At MAPAL the quality of the advice and support matches the performance of the tools“, Patrick Vilfan said. Because the support provided by the field service is also an important aspect for Bonertz Technik. Klaus-Dieter Leick keeps in constant contact and provides samples for tests when new demand or interesting new products become apparent. Added to this is MAPAL‘s own initiative, for example if a specific product from the standard range is not immediately available from stock. „In such a case, we receive direct alternative suggestions regarding similar tools with which the required machining result can also be achieved“, Mr Vilfan said. This support has also contributed to MAPAL becoming a preferred contact for new tasks..