A connector usually contains several stamped and bent parts that must be manufactured with high precision. In order to prove and document the required quality (and ultimately to optimize the process), Unimet has invested in four Werth Videocheck  multisensor measuring machines, which are used during production and in the measuring laboratory.

Each production area at Unimet has a measuring cabin in which the workers have a Videocheck S coordinate measuring machine for measurements during production.

With over 46 years of experience, the Unimet Group has developed into a technology and quality leader in precision stamping and bending. Every year, the company in Rieden am Forggensee, and its subsidiary Leukert in Kaufbeuren, produce several billion complex stamped parts, most of which are electroplated and used in connectors. They are supplied worldwide to the automotive, electronics, electrical, lighting, aerospace, and telecommunications industries. The core competencies of the Unimet Group, which employs around 430 people, also include the development and production of high-performance tools and the manufacture of plastic composite parts as a system partner.

After Unimet owner Rudi Kolb founded the company in 1970, he became convinced that quality and precision were indispensable for winning and keeping customers. All employees have internalized this maxim, especially Stefan Kolumban, the head of quality assurance: “I enjoy working with my team to help make our products better and better. We are continuously looking for ways to improve processes and learn better ways in order to ultimately be successful together with our customers.”

Kolumban especially appreciates the expertise of its 16 employees, but also the high-quality equipment that enables the realization of a zero-defect strategy. Since the management sees quality as the basis for success, investments were made in high-performance coordinate measuring technology. This includes – for more than 20 years – the CNC-controlled 3D coordinate measuring machines from Werth.

By the early 1990s, Kolb realized that it would no longer be enough to just supply excellent products. High-precision measurements reduce waste, and the customer can convince himself of the quality of the stamped-bent parts by means of the measurement reports. He and his quality managers realized that the Werth 3D coordinate measuring machine Videocheck S was the best on the market. The machine impressed them with its flexibility and precision, due in part to the design principle with a tension-constant guide system.

Stefan Kolumban (right), Head of Quality Assurance at Unimet, discusses the requirements of a typical stamped part with Werth Sales Manager Detlef Ferger.

After Unimet confirmed the usefulness of the machine in daily practice, the Rieden-based company invested in three more Videocheck S machines in the following 14 years – in line with the company’s growth. “All these years the machines were in use day in, day out and extremely reliable,” praises Kolumban. “All four still measure within the specification. This is remarkable and speaks to their exceptional quality.” Since sensor and control technology had developed considerably in the meantime, the decision was made at the end of 2015 to purchase four more of these measuring machines in the course of the following year.

Werth executive vice president and sales manager Detlef Ferger is pleased about the long-standing cooperation that he directly experienced more than 20 years ago: “I still remember it well. Back then, as a young application engineer, I had only recently joined Werth. Unimet was one of the first customers I was allowed to train in the use of our equipment. Since the mechanics of the ‘old’ machines were still fully functional, Werth accepted them in exchange as used machines.”

Kolumban explains the reason for the decision to give up the equipment and invest in new ones: “It is not because we could no longer meet any standard or customer requirement. But with our new machines, which are all at the same level of development, we are faster and more flexible in terms of staff deployment. In addition, there is no need to adapt measuring programs if I want to change to another measuring machine, and we are technically up to date. After all, the requirements of our customers will continue to increase in the future.”

As an advantage of the new machines, he emphasizes the improved illumination for the image processing sensor, which today works on an LED basis. Kolumban explains: “We get brilliant images so that we can measure very precisely in the cutting area. Also the measuring speed has increased. Thanks to the modular machine concept and the Werth Zoom with adjustable working distance and light incidence angle, we have all the options we need to ensure that no customer request will intimidate us.”

All Videocheck S machines follow the proven design principle of their predecessors, but have been improved in numerous ways. First is the guide system, in which the preload of the X and Y axes is magnetically generated to avoid expansion-related stress on the bearing and thus loss of precision. Since the guideways are manufactured in a precision machining process, the components can be assembled without mechanical adjustment or clamping. This type of machine offers very high long-term stability over many years of service life.

With the new magnetic interface for sensor technology, the Werth  Multisensor System, Unimet can expand the Videocheck S almost at will. For example, conventional touch probes, laser sensors, tactile sensors, or the Werth fiber probe can be exchanged fully automatically and without offset in front of the likewise patented zoom optics. Kolumban appreciates this option: “At present, we only measure optically in production. But who can tell whether this will still be sufficient in a few years? With the  Multisensor System, we can react quickly and easily to growing demands and add new functions.” Already today, the fourth Videocheck S unit is equipped with additional sensors such as the SP25 probe and the Werth Laser Probe WLP integrated in the beam path of the zoom optics for fast scanning of the workpiece surface. This machine serves as a reference instrument in the quality assurance laboratory and is used for a wide range of measuring tasks due to its flexibility.

The Videocheck S installed in the quality laboratory has a Werth Laser Probe integrated in the image processing beam path and a tactile scanning probe system that can also be exchanged without offset via the Werth Multisensor System.

Measurements are made during the process

One of the new Videocheck S coordinate measuring machines is installed in each of these production areas. “In the air-conditioned measuring cabins, a special decoupling system prevents production processes, such as punching, from influencing the measuring result,” adds the head of quality assurance. The machines are used for worker self-testing during production. The employees are trained internally and have to take an examination every two years to obtain the “license to measure.” The machines are supervised by two measurement technicians who regularly attend advanced training courses at Werth.

“Because most of our customers come from the automotive industry, the requirements are particularly high,” explains Stefan Kolumban. Increasingly, measuring equipment capabilities and, of course, the traceability of measurement results to international standards are required. “This excludes manual procedures,” explains Kolumban. “More often, we use Werth’s measurement technology, which meets all the requirements. Our specialists create the necessary measuring programs on the respective machines and the workers then execute them as required using freely programmable input masks.”

Each product is only released if it has passed the specified test plan. Unimet also uses the measurement results for computer-supported quality assurance: the CAQ software provides a long-term view of the tools, which provides information about wear and tear and downtimes. This allows the company to derive optimizations that will be beneficial for the next generation of tools. This also applies to individual tool components.

Kolumban: “The interaction of Werth Mess- and our CAQ software allows us to carry out a wide range of statistical analyses and thereby optimize our processes and ultimately our products. In this way, we have been able to provide significant advantages to our customers.”

Unimet specializes in the production of high-quality and technologically advanced stamped and bent parts and complete assemblies.

Versatile use of Videocheck S
Unimet uses the measuring instruments in a variety of ways. The reference instrument in the measuring laboratory is also used for test measurements and first article inspection, as well as for creating new measuring programs and as a backup machine for quality assurance in emergencies. Machine capability tests are also carried out here. In addition, Unimet uses the measuring equipment for process re-qualification, which must be carried out at regular intervals specified by the customer. For Kolumban, this technology is “the best available on the market. For the future, I could also imagine a Werth coordinate measuring machine with computed tomography.”