Kistler integrates force sensors into the tool holder of electromechanical joining systems

A basic principle in measurement technology says that the closer a measurement is taken to the point of action, the more accurate the results will be. This is equally true for joining systems whose sensors check whether the system is applying the correct force. Thanks to telemetry, the force sensors on the new electromechanical joining modules in the NCFx Pro series from Kistler are integrated in the tool holder, more precisely on the ram, now, exactly where the joining force is generated. The transmission from the sensor to the electronics in the joining module housing is purely digital. Data are transmitted via an EtherCAT interface to the maXYmos NC process monitoring system from Kistler. This digital communication offers several advantages: it is less susceptible to interference while offering extensive diagnostic options and direct access to additional sensor data, such as the built-in temperature sensors. What’s more, cable length no longer affects measurement accuracy, system stability is further improved, and sources of error are minimized.

Thanks to the new sensor position and digital data transmission, the energy-efficient servo presses achieve a new level of precision for applications in the electronics industry, medical technology and the automotive industry. “Especially in steering, chassis, and axle assemblies or other safety-relevant components, precision and reliability are core requirements for our customers. The new product family offers crucial advantages here,” reports Alexander Müller, who is responsible for these joining systems at Kistler.

The strain gauge (DMS) force sensors cover measurement ranges from 2 to 120 kN, while the piezoelectric force sensors cover ranges from 0.05 to 120 kN. Depending on the sensor, seven predefined measuring ranges can be used with the piezoelectric sensors via maXYmos NC process monitoring system. This selection enables more accurate measurements while offering high overload protection, particularly in the smaller measuring ranges. Users also benefit from reduced spare parts inventory (“one fits alle”) and flexible system adjustment without re-calibration.

Both joining-module variants – with either piezoelectric or strain gauge (DMS) force sensors – are designed with a 20 percent overload reserve. This reserve provides additional safety if the actual joining force is higher than expected. Both sensors are mechanically compatible, can be easily exchanged or reordered from 2 kN and can be returned for calibration. An optional DAkkS calibration is already in preparation. Thanks to plug-and-play, the sensors are automatically recognized, including their sensitivity and measuring ranges. This avoids errors during commissioning and greatly simplifies handling.

Simplified integration and commissioning of the new electromechanical joining systems thanks to their compact design

At speeds of 250 to 500 millimeters per second, the new NCFx Pro electromechanical joining modules from Kistler achieve significantly higher cycle rates and thus increased productivity in automated manufacturing processes. They also feature a more compact design that allows for smaller center distance and reduces space requirements, simplifying integration into existing machine concepts. Another advantage: up to 60 kN, only a single cable is required to connect the motor for commissioning. The new servo amplifiers ctrlX DRIVE are also more compact and save additional space in the control cabinet. A safety-zone box for the functions SMES, SMST2 and safe limited speed is no longer necessary.

The joining module itself also features a plug-and-play architecture, allowing users to commission it quickly and without extensive parameterization. The externally located lubrication port enables simple maintenance and connection to a central lubrication system.

Forward-thinking: an accelerometer for future predictive maintenance functionality is already integrated

When developing the NCFx Pro systems series, Kistler placed particular emphasis on future viability. Another sensor-based expansion is already underway, as Alexander Müller reveals: “An accelerometer for an upcoming predictive maintenance feature is already integrated into the NCFx Pro joining modules. This can be activated later via a software license through the maXYmos NC process monitoring system — without any further adjustments.