Interview: Trends in Force Measurement Technology Interview: Trends in Force Measurement Technology | HBM

Force Sensors Today, Tomorrow, and the Day after Tomorrow: An Interview with HBM Experts

In 2020, HBM introduced many innovations in the field of force measurement technology, such as the KMR+ force washer for flexible use or the C11 ultra-miniature sensor. The portfolio has also become increasingly "electrified", which began with the availability of C9C and U9C sensors as active sensors with permanently connected in-line amplifiers and is now to be continued.

In this interview, the experts in the field of force measurement, Thomas Kleckers and Markus Gräf, tell us how they see the future of the market and what they are doing to ensure that HBM remains one of the dominant players in the global competition in the long term.

Is force measurement technology crisis-proof and can it exist in the long term?

[Markus Gräf] Force transducers are used in a wide variety of applications and markets, which requires us to allow for great flexibility in terms of the products’ usability. We need to keep in mind a lot of framework conditions to ensure that our sensors always deliver the expected performance in their wide range of applications. However, we see this as an advantage, in general and in the long term.

[Thomas Kleckers] By using the sensors in research and development, production monitoring, or also as reference transducers, fluctuations in individual areas can be compensated for. This broad positioning makes force sensors a market of the future. The number of sensors required will increase in the future because modern production methods – keyword industry: 4.0. – require much more information, and the control systems are blind without sensors. We also see a growing market in the field of testing, as more and more sensors are being used in tests, for instance.

What other trends do you consider important?

[Thomas Kleckers]

There has been a trend toward increased accuracy for a long time. The possible measuring range has been extended. For example, instead of 4 sensors, only 2 are needed to cover forces between 50 kN and 5 MN. Moreover, an increasing number of tests can be performed without time-consuming modifications of the test stand and more precise process monitoring results in fewer rejects. Therefore, precision is not an end in itself, but rather an economic advantage for our users.

Furthermore, customers demand flexibility in terms of the ordering process and design: Force sensors must be adaptable and operational without requiring major efforts such as soldering work. Another development in recent years is the demand for robust force sensors that can withstand a wide range of environmental conditions and provide reliable measurement results everywhere. This is not only true for humidity or large temperature variations but also for resistance to shock and vibration, which has become extremely important. Further, we see that users are interested in increasingly smaller sensors. However, at the same time, high demands are placed on the performance of these miniature transducers. Overall, the requirements are increasing. At HBM, we are very well equipped since we have all the necessary testing equipment for shock and vibration tests, as well as an accredited laboratory for electromagnetic compatibility in-house, with the advantage of direct access for our development engineers.

Markus Gräf

Team Lead Development Force Measurement

Markus Gräf is a mechanical engineer and has worked at HBK since 2009. Toward the beginning of his career, he developed customer-specific force transducers. Since 2013, he has led the development team for force, pressure, displacement, and strain sensors and continues to develop force transducers.

Thomas Kleckers

Product and Application Manager Force Sensors

Thomas Kleckers has worked at HBM – now HBK – since 1992. After his time as a development engineer for strain gauges, he took over product responsibility for force sensors in 2009.

How do you know where the market is going?

[Markus Gräf] Due to the wide range of applications, there is no single market or trend that fits all and that we are working toward. We are pursuing different approaches for that reason. A roadmap specifies the framework, but it is adapted several times during the process. The input for the roadmap comes from a mixture of customer feedback, sales, market research, and ideas that have emerged in internal discussions. However, observations in the application and dialog with the users are particularly important.

[Thomas Kleckers] It is essential to understand what the customers want to do with the force sensors so we can also understand what the appropriate product has to look like. Therefore, we think of our customers’ tasks as the starting point for the product. 

Has there been a miscalculation in your time at HBM resulting in the development of a flop?

[Both] No.

[Thomas Kleckers] Of course, some approaches were rejected. However, we have yet to develop a product (in force measurement technology) that has turned out to be a failure. The team controls each other, and from the time a project has reached a certain status, customer feedback plays a big role.

[Markus Gräf] Key customers are involved in the development of larger projects; they integrate our products into their applications before the official release. If they are dissatisfied, their feedback helps us make our force transducers better from the very beginning.

How do you achieve short development times and the fastest possible time to market?

[Markus Gräf] We draw upon a proven team of developers in which everyone brings clear strengths to the table. Internal problems have been systematically identified and eliminated in recent years. We have also significantly improved the interlinking of development and production, which is why we can now set up new series much faster, and in some cases, production and sales releases coincide.

[Thomas Kleckers] Fast processes are supported by the development, production, testing, and calibration taking place centrally in one place—here, in Darmstadt. We also benefit from the cross-departmental use of components such as strain gauges, printed circuit boards, or spring elements. However, our modular system has turned out to be the most valuable. It allows us to extend new developments to other products in the portfolio. This system offers the customers different options and better quality with the same delivery time and it is also reflected in the part numbers. The modular system accelerates production and development and is also customer friendly.

[Markus Gräf] The ideal portfolio is not characterized by a high number of part numbers. Instead, it should be kept lean but multifunctional. The aim is to enable the customer to cover different applications as easily as possible.

Customer friendliness is now as important as technical innovation. What are you doing in this respect?

[Thomas Kleckers] Since test engineers have to cope with an increasing number of sensors, as already mentioned, we offer a wide range of configuration options, matching accessories, and various plug-and-play solutions to keep the installation and commissioning manageable. TEDS eliminates the need to adjust the amplifier module. Further, standardized interfaces are becoming increasingly important beyond the force range, as well. We also think ahead and perform numerous tests to ensure that the application does not become a disaster. To sum it up, we make every effort to provide reliable sensors and precise specifications. If the customer still has problems finding the sensor that fits best, our sales department is readily available to provide support.

[Markus Gräf] Often, other teams are also involved in customer issues to provide a quick fix. Our goal is not to let any customer down!

How do you test your force sensors to guarantee customers a certain quality?

[Thomas Kleckers] Important parameters such as TC0, bending moment, hysteresis, or the rated output are tested for all force transducers. Other parameters do not allow 100% testing; for such parameters, we implement careful type testing and reliable processes.

[Markus Gräf] The challenge is to know the characteristics that require to be tested 100% and to adapt the production tests to this; adaptations are also considered in terms of costs. Our processes are optimized in a way that the test requirements are cost-optimized without compromising on reliability or compliance with our specifications in the technical datasheets. We look very closely at that. Moreover, the quality department deliberately focuses on things that have not gone quite as smoothly in development.

[Thomas Kleckers] We know what we need to test. In practice, the result is fully satisfactory – the customer receives absolutely reliable datasheets that do not promise too much. If used correctly, HBM force sensors can be used for decades without any problems and need for repair, which is also economically profitable in the long term.

By the way...

Thomas Kleckers obviously likes the whole force measurement portfolio, but if he has to name a favorite, it’s the U10M because the sensor is both very precise and extremely tough. The U9C and C9C miniature force transducers take second place, as they combine reliability and a small footprint.

Markus Gräf took a small break from his parental leave only for this interview. As a developer, he prefers the reference transducers, tricky development tasks, and overall strategy development tasks in collaboration with Thomas Kleckers.