EROWA Report BUNORM AG

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REPORT - BUNORM AG

Acid test for the Heavy PowerChuck The Bunorm company in Aarwangen (Canton of Bern, Switzerland) is specialized in the machining of large mechanical components. As a test customer, Bunorm put EROWA‘s new Heavy PowerChuck (HPC) tooling system to genuine acid test. The result is more than encouraging. EROWA has pursued the aim of producing a tooling system for large and heavy workpieces for some time. In order to gain a deeper understanding of the relevant requirements and peculiarities, the company contacted Bunorm as early as 2015. What is important when it comes to machining heavy components? How do you clamp a very large workpiece? „Subsequently, Bunorm provided important and valuable inputs in the development of the HPC,“ says Benjamin Wagner, Product Manager at EROWA. „And this was all the more the case when we decided in 2016 to configure and test a system that was tailored to the company‘s specific requirements.“

Stefan Gygax, project leader Bunorm AG: „The entire handling process has been significantly simplified“.

Well-thought-out solution The systems has been in operation since January 2018. Four HPC clamping modules are fitted to a base plate. A crane is used to clamp a magnetic clamping plate onto these modules; this clamping plate then fixes the actual workpiece by means of ma-

REPORT - BUNORM AG

gnetic force. For this purpose, it has 132 mobile pole extensions, which ensure an absolutely level support. The component that has been clamped in this way is machined by a gantry machining center on up to five sides at the same time. „We run two such pallets for the gantry machining center,“ explains Bunorm project leader Stefan Gygax. „This gives a considerable boost to flexibility and speed, since when one plate is in the machine, the next can already be prepared.“ It is also important that the system has an open check: the control box displays whether the clamping modules are open or closed; this prevents operators from inadvertently trying to lift the pallet in closed mode, which would cause damage. Bunorm also operates a second HPC clamping fixture, which is used on a turning and milling center. Here, the workpieces measure up to 1,600mm. Simplified handling Stefan Gygax details numerous other advantages: „The entire handling process has been significantly simplified. Thanks to the precentering spigots, the pallet is aligned accurately right from the start, errors have become almost impossible. The datum point remains the same, as does the alignment of the clamping modules to each other, which of course is good for repeatability,“

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REPORT - BUNORM AG

he says. „The pallet can be changed by one person; setting-up and resetting times have been cut substantially. Previously we had to factor in one to two hours for resetting on the magnetic plates, now this takes something like just over five minutes,“ he says enthusiastically. The new tooling system is used to finish aluminum structures and to machine steel batts with a weight of approx. 1,500kg. „The tooling system stands the test even with such great weights,“ Gygax continues: „The load-bearing capacity is not different from direct clamping to the machine table in any sort of way.“ Successful cooperation Stefan Gygax is enthusiastic about cooperation with EROWA. „We were able to configure the Heavy PowerChuck tooling system to fit our products in close and straightforward cooperation with EROWA, and we were even involved in its development up a certain point,“ he says. The philosophies of the two companies are very similar, and EROWA is innovative and solution-oriented. „This test is really a success story and very productive.“

Bunorm AG Machine-building is the core business of the family firm that was founded in 1965. A particular specialty is the machining of large machine components, including sophisticated assemblies and small series. The company is capable of processing components measuring up to 18,000mm an weighing up to 75t. It also runs its own engineering department for special machine building. With its extensive range of machinery, its own assembly department and a locksmith‘s shop with welding robots, the ISO 9001 and 3824-2 certified company serves an international clientele. At present, Bunorm employs 76 staff, including nine trainees.

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