In many applications today, displacement transducers or displacement sensors are required that are not only mechanically and electrically robust, provide accurate measured values and work reliably, but also offer a wide operating temperature range and a favorable price-performance ratio. Development has not stopped here either: Versions with integrated electronics provide either standardized current or voltage signals and variants with a small M8 connector are extremely compact. There are numerous applications for this, particularly in mechanical engineering, for example in sheet metal processing for path detection in clinching systems and tongs.
© BTM
Potentiometric displacement and angle sensors are widely used in both industrial and mobile applications, as comparable measuring speeds, linearity and hysteresis values as well as resolutions and temperature ranges can otherwise only be achieved with significantly greater effort. The sensor specialist Novotechnik has therefore continuously developed potentiometer technology in addition to contactless sensor technology.
Today, many different versions of potentiometric displacement transducers and probes are available, which are suitable for many applications in measurement and control technology thanks to their space-saving design. The potentiometric displacement transducer series T, for example, is available for measuring ranges from 10 to 150 mm. It offers a high repeat accuracy of 0.002 mm, a long service life of up to 100 million movements and very good linearity values of up to ± 0.075 percent.
In addition, the sensors are not only available with a cable connection, but also with compact M8 plug-in connectors, which simplifies installation even in confined spaces. The latter was an important argument for the special machine builders at BTM Europe Blechverbindungstechnik GmbH to use a displacement sensor from this series on their clinching systems.
BTM is one of the world’s leading manufacturers of clinching systems and complete production lines. The name BTM stands for “Bending Tools & Manufacturing” and recalls the beginnings of the BTM Corporation after its foundation in 1966. In the meantime, the BTM Group has become firmly established in the fields of mechanical joining technology and clamping technology, both in the automotive sector and in general industry.
Clinching: economical joining technology for dimensionally stable joints
Clinching, also known as clinching, is a mechanical and economical joining process in which sheets of different thicknesses or different materials are joined in a cold forming process. In this process, two or more sheet metal layers (joining partners) are joined together by a process combination of deep-drawing and broadening, embossing and form-fitting.
© BTM
The range of applications extends from individual sheet thicknesses from 0.10 mm up to a total sheet thickness of around 10 mm. “The process uses an undercut to create stable connections that can withstand high static forces as well as dynamic stresses,” explains Christian Bohnert, Managing Director at BTM Europe. “Our clinching process is insensitive to variations in sheet thickness or surface coatings. It therefore offers a very efficient way of securely joining bare or otherwise coated (e.g. painted) sheets of different types, grades and qualities. Applications can therefore be found in a wide variety of sectors, for example in the automotive industry, building technology, the household appliance industry, ventilation and air conditioning technology and the furniture industry. Last but not least, electrical engineering manufacturers rely on our clinching technology for connections to live components.”
An important parameter in clinching is the penetration depth, i.e. the distance the tool travels. To ensure reliable results, the sensor used must provide accurate measured values, be as compact as possible and work reliably. Christian Bohnert recalls: “We have been using sensors from Novotechnik on our machines for over ten years. The fact that the potentiometric displacement sensors are now available with the small M8 connector was very convenient for us because it makes assembly easier. In addition, the compact probe can also be used in the clinching tongs designed for mounting on robot arms, where there is only limited installation space available.”
The short-travel sensor used has a measuring range of up to 10 mm and provides an output signal of 0…10 V. “This means that the measuring sensitivity is very high,” adds Christian Bohnert. Another special feature of the pushbutton is its robust, industrial design with a double-bearing push rod that can absorb lateral forces. The design of the rear end stop simplifies the mechanical coupling of automatic retraction devices. The button is not affected by oscillations or vibrations and works reliably at ambient temperatures between -30 and +100 °C.
© BTM
Contactless alternatives
Potentiometric displacement sensors, such as those used in the Clinch systems, will continue to hold their own in many applications in the future due to their good price-performance ratio, especially as the TE1 series also offers a variant which, thanks to integrated electronics, provides an absolute voltage or current signal at the output that can be connected directly to the analog inputs of the control system.
Nevertheless, there are also practical alternatives for “contactless” devices. The displacement transducers in the LS1 series, for example, work inductively and are fully compatible with the potentiometric T series in terms of their dimensions.
The TF1 inductive displacement transducer, which is available in standard lengths from 100 to 1,000 mm, is ideal for fast positioning tasks. The update rate of the measuring system reaches 10 kHz, which means a time delay of only 0.2 ms between the actual position and the corresponding measured value. The absolute magnetostrictive displacement transducers in the TP1 series, which are suitable for measuring ranges up to 4250 mm and, like the TF1 series, have an unlimited mechanical service life, also operate contactlessly.
Background
Novotechnik, headquartered in Ostfildern, Swabia, has been a pioneer in the further development of measurement technology since 1947. In Germany alone, around 200 employees are now working on top performance. The result is high-performance displacement and angle sensors that have become an integral part of manufacturing, control and measurement technology and automotive applications worldwide. The wide-ranging product portfolio includes displacement and angle sensors with different functional principles, special solutions for the automotive sector as well as transducers and measuring devices. This covers practically all conceivable tasks; for special application requirements, specific solutions are developed that are optimally suited to the respective application.
Web:
www.novotechnik.de