Manufacturing Technology

Zollner Elektronik AG manufactures a huge variety of bolted joints, and must ensure they are reliable and compliant with the relevant standards. That’s why Zollner puts its trust in mobile testing systems from Schatz, a Kistler Group company. Across many different industries, Schatz systems help to safeguard know-how and quality in the long-term – playing a key part in preventing costly recalls.

Since 1965, when Zollner Elektronik was founded as a one man business in Zandt (Bavaria), the firm has become one of Europe’s most prominent electronics manufacturers. Single parts, modules, complete devices and even complex systems: Zollner covers all these product types, across diverse sectors of industry and for countless applications from rail technology engineering to telecommunications.

Bolted joints and screwed connections are indispensable elements of many electronic assemblies. They are used in printed circuit boards, control units and a host of other products manufactured to order by Zollner – all of them are held together by bolts and screws. VDI Guideline 2230 provides a standard for calculating and designing high strength bolted joints – but new standards for specific applications are constantly being added in the numerous industries where Zollner operates. This creates a level of complexity that cannot be underestimated.

Michael Zeller, who joined Zollner in 2007 and is responsible for test equipment monitoring and measurement technology, explains the situation: “Over 2,000 torque tools are currently in use across our company. All bolted joints that are assembled with those tools have to be tested for compliance with the standards – and on top of that, the tools themselves have to be calibrated at regular intervals.”

Standard compliant calibration of torque tools
This means that testing and documentation of all bolting processes is a key function the company must perform to safeguard against system outages or product recalls. “When I started at Zollner, most of the calibration work was still outsourced. But we weren’t satisfied with the processes – especially as the solution that was implemented was only loosely based on the standard. That prompted our decision to consolidate all our know-how on bolt testing in Zandt, Germany,” mentions Michael Zeller.

While seeking out suitable solution providers, Michael Zeller came across Schatz, a technology leader in the bolt testing sector and a member of the Kistler Group of Switzerland. He made contact with the company at a trade fair and was soon convinced. “Schatz listened to us very carefully, and they were extremely flexible regarding implementation – they didn’t just offer us off-the-peg solutions. That’s exactly the sort of advice you hope to receive!”

The project is already paying dividends, with over 2,000 torque tools that need calibration at least once a year, the annual cost savings amount to at least €60,000 – and that doesn’t even include the time gained while the tools would otherwise be out-of-house.

The Schatz products that Zollner is currently using include the InspectPro for testing bolted joints during production. The InspectPro is a portable testing system that measures torque, preloading force and rotation angle – guaranteeing process capability for bolt assembly. Since 2016, Zollner has also used combiTEST for standard compliant testing and calibration of all torque tools, regardless of the manufacturer. The testing system from Schatz has been complemented by external simulators to avoid the need to dismantle tools for calibration purposes. In addition, a handling system to make calibration even easier was integrated especially for Zollner.

In-house solution completed in less than four months
Thanks to mobile testing systems from Schatz, Zollner has successfully improved its internal real net output ratio, and the firm has been able to accumulate immense know-how on the various bolting processes across different departments. Alongside the cost factor, process reliability also plays a critical part. “All our customers have one thing in common – their technical requirements are increasing all the time. There are always new standards and guidelines to accommodate. Therefore, the more different sectors and customer groups we serve, the more standards we have to meet,” notes Michael Zeller.

Manufacturer independent testing of all torque tools in compliance with the applicable standards, directives and guidelines has been an enormous success for Zollner. Over 95% of calibrations are now performed in-house, with excellent efficiency in terms of costs and time. Rapid implementation was another reason for Zollner’s exceptional level of satisfaction with Schatz. After Michael Zeller had convinced the board of directors with a cost-effectiveness calculation, less than four months passed between the start of work and the final training from Schatz.

Vision for the future
It comes as no surprise that Zollner intends to continue expanding its collaboration with Schatz. Two additional InspectPro solutions are planned, as well as another combiTEST system for the firm’s facilities in Hungary. “It’s going to become even more important to comply with all the standards and guidelines required for product liability. Traceability is another critical aspect,” Michael Zeller adds with conviction.

That’s why he has already developed a vision for the future, which he calls the ‘professional testing chain’. “When the new Schatz combiTEST arrives for our sites in Hungary, we shall also implement the server solution for the first time. Our long-term goal is to have transparent data on the status of all tools at our 18 facilities across the globe – and what’s more, to have automated input of new standard requirements. That would guarantee that each and every bolted joint required by our customers meets the standards – throughout the world.”