Smarter clamping and gripping

The screeching sounds of machine tools being operated by experienced machinists in Hall 1 could be heard over and over again, sending shivers down everyone’s spines before moments later almost silently sliding through the workpiece. SCHUNK, the competence leader for gripping systems and clamping technology, calls its intelligent clamping technology “Smart Clamping”, which will help ensure that even the most demanding processes will run smoothly in the future. The iTENDO, an intelligent toolholder that monitors the cutting process directly on the tool, and enables real-time control of the cutting parameters, is one of these smart technologies. For the first time, it will become possible to record vibrations, chatter marks and tool failures in real time and to adjust the process immediately and fully automatically as soon as deviations occur. The smart tool, which is set to reach the market in 2019, allows complete documentation of process stability, unmanned limit value monitoring, tool breakage detection, and real-time control of the speed and feed rate.

For Henrik A. Schunk, Chief Executive Officer of SCHUNK GmbH & Co. KG, smart clamping devices and gripping systems will assume a key role on the way to the smart factory due to their “closest-to-the-part” position. “The goal is comprehensive communication between all components, maximum process transparency for users, while at the same time maximum data security as well as a dynamic reaction to events”, says Henrik A. Schunk, outlining the company’s roadmap. “The AMB has shown that smart technologies are within reach and that the visions of the past few years are starting to become concrete solutions,” emphasized the entrepreneur. “Intelligent components are creating important prerequisites on the way to Industry 4.0 and are paving the way for new fields of application with maximum flexibility and efficiency.”

Monitoring and flexibilization of the processes are the goals
Under the motto “Open. Smart Clamping in Smart Factories” SCHUNK left no doubt of its pursuit of a leading role in the digitalization of manufacturing processes. The concept is that due to their exposed position, clamping devices and gripping systems play a special role in this process: They enable more flexible processes and permanent process monitoring and optimization directly on the workpiece. SCHUNK is making an impressive presentation of how sensitivity, connectivity, and a high degree of functional integration become key factors in the real-time monitoring of clamping devices. For example, clamping force, clamping path or vibration behavior during machining can be permanently recorded and analyzed. If deviations occur while a process is running, the machining parameters can be adjusted completely automatically in real time based on the data detected. With the aid of various intelligent clamping devices, it becomes clear where the journey is going:

Monitoring of pull-down force, clamping slide position and workpiece presence
The smart quick-change pallet module SCHUNK VERO-S NSE-S3 138 enables permanent monitoring of the pull-down force and clamping slide position. For this purpose, strain gauges, measuring amplifiers and inductive analog sensors were directly integrated into the module. Furthermore, the presence of the workpieces or clamping pallets can be detected by means of inductive proximity switches. This ensures that the entire clamping process runs under optimal conditions. Power supply and signal transmission is carried out through cables via spring contacts. Since the measured values are output as analog signals (0 to 10 V DC), simple signal processing is possible. The complete intelligence has been integrated into the module in a way that the dimensions completely match with those of the conventional VERO-S NSE3.

Variable clamping force
Going one step further, we have the clamping force blockSCHUNK TANDEM KSE 100. In addition to integrated monitoring of the clamping path and clamping force, this intelligent powerhouse is also capable of individually adjusting the clamping force and position of each chuck jaw to the respective workpiece. The advantage: Chuck jaws can be pre-positioned in the ongoing process, thus reducing the cycle time. In addition, it is possible to reduce the clamping force in order to prevent deformation or damage to the surface. The required sensor technology is also fully integrated into the component.

Intelligent toolholder
One undeniable highlight in the field of tool clamping technology is the smart hydraulic expansion toolholder SCHUNK iTENDO, which was developed in cooperation with the Vienna University of Technology and TOOL IT GmbH Vienna. “The iTENDO is a milestone in toolholder technology,” emphasizes Henrik A. Schunk. “For the first time, we combine the outstanding mechanical properties of our flagship TENDO with the possibilities of digital process monitoring.” According to Friedrich Bleicher, Managing Board Director of the Institute of Manufacturing Technology (IFT) of the Vienna University of Technology, and founder of TOOL IT, the intelligent toolholder facilitates a unique synergy: “Embedded systems technology combines the highest degree of process transparency with the potential of autonomous process control without users having to do without the quality and performance of proven precision toolholders,” says Bleicher.

During machining, the intelligent toolholder permanently analyzes the machining process. If the process becomes unstable, it can either be stopped in real time and without the intervention of the operator, reduced to previously defined basic parameters, or adapted until the cut returns to a stable range. On the one hand, the system enables complete documentation and limit value monitoring as well as an improvement of the machining quality by automatically adjusting the cutting data during vibration. Moreover, the intelligent toolholders should additionally enable an analysis of the tool condition as well as an increase in the metal removal rate. The system is extremely easy to retrofit without the need for modification or replacement of machine components. Since the algorithms run autonomously and the operator defines only exact limit and reactions, no expert assessment of the data determined is necessary. Instead, the system manages the process autonomously and in real time based on the specifications.