The gripper is the last and central link in the kinematic chain of a handling device, because it brings one thing to the point – a component, a workpiece, any large or small intermediate or end products. Grippers are therefore of central importance in production. The efficiency and safety of the entire process depend on the functionality and performance of the end effector. More than 90 percent of grippers operate pneumatically – for decades, they have proven themselves as the "top dogs" in automation technology thanks to their durability, freedom from maintenance and robustness in all industrial sectors. These allrounders remain indispensable due to their reliability and variety. This is because they ensure reliable gripping of workpieces from very small to very large with a wide range of geometries and in any environment.
Pneumatic grippers, classics in automation, have long since started their journey into the future. The integration of a sensor system, as provided by SCHUNK PGL-plus-P presented here, opens up new possibilities in terms of process monitoring, safety and individualization. The direct connection to the controller allows the gripping module to be diagnosed at any time; process and status parameters that can be called up in real time form the basis for various data analyses. The integration of modern digitization features directly results in greater safety, efficiency and cost-effectiveness. An integrated IO-Link sensor system, for example, transmits the finger position over the entire range of stroke and can accurately distinguish between workpieces – a real plus with increasing part variance and individualization. This eliminates the need for external sensors, which simplifies acquisition, commissioning and repair.
Automation expert SCHUNK is constantly working on further development of pneumatic actuators and preparing them for modern handling scenarios in which pneumatic grippers will continue to be indispensable in the future. This is because they have many advantages: The user benefits from high cost-effectiveness and easy commissioning, as pneumatic systems are simple in design. Applications with pneumatic grippers achieve very high operating speeds; for example, in high-speed pick-and-place applications, fast cycles are realized with the highest possible reliability and the lowest possible manufacturing down-times.
Other high-speed applications for pneumatic grippers and modules include highly dynamic handling cells in assembly automation.
Speed, process safety, reliability and durability make pneumatic grippers indispensable for many industrial applications. These features ensure productivity and reliable processes. Pneumatic modules are relatively lightweight, which means that the robot's load capacity can be utilized efficiently for the actual handling process. Clearly, the combination of weight, power density and price-performance ratio is a plus point and unique selling point for the pneumatic gripping modules. Their mechanical robustness means they can often withstand individual force and torque overloads without suffering damage. A further plus point is their suitability for use in areas subject to dirt, for example in metal-cutting production in the vicinity of machine tools and in cleaning systems. They work without problems in harsh and demanding operating environments with moisture and dust and, in suitable versions, also in potentially explosive atmospheres. Pneumatic grippers also impress with their high performance, especially in medical technology applications and in the laboratory and pharmaceutical sectors. Thanks to their temperature robustness, they are irreplaceable, for example, in forges and foundries, where they can handle large and heavy red-hot workpieces with appropriate protection.
The reliability of the entire gripping and handling process depends to a large extent on the gripping force that has to be applied to the object during the gripping process. It must counteract all forces that occur – these include not only the weight of the workpiece but also process forces and inertial forces due to translation and rotation during the handling process. The gripping force must ensure that the workpiece is picked up and held securely. The component must not be allowed to fall under any circumstances, as this can have serious consequences – from mechanical destruction of the component or the entire system, to worker injuries, to chemical or biological contamination when used in laboratory cells. For example, a gripping force maintenance device is often required to maintain the gripping force in the gripper in the event of a power failure. Users of industrial grippers get this functional safety fully integrated into the new universal gripper PGL-plus-P from SCHUNK, which has the certified, safe gripping force maintenance GripGuard directly on board – a worldwide first! GripGuard takes gripping force maintenance to a new level. At least 80 percent of the nominal force is retained. This rules out the chance of uncontrolled jaw movement in the event of a sudden drop in pressure, and no workpiece is lost in the event of an emergency stop.
SCHUNK has developed the flexible and versatile PGL-plus-P for the premium sector – for improved safety in the process while simultaneously supporting a wider range of applications. With a gripping force of 220 newtons in size 10 with 20 millimeters overall stroke and up to 1,300 newtons in size 25 with 50 millimeters overall stroke, it closes the gap between universal grippers and long-stroke grippers. In addition to certified gripping force retention, it is equipped with integrated IO-Link sensor technology. Users can switch between IO-Link and SIO modes.
With the “Gripping Point Mode” and “Gripping Range Mode”, SCHUNK also offers two sensor profiles for easy programming of workpiece positions or areas. The gripper has a flat and compact design, is equipped with the proven and robust multi-tooth guide, as well as the standard IP64 sealing; the PGL-plus-P is therefore suitable for harsh environments. When combined with an integrated air purge connection, the protection class can be increased to IP67. Due to H1-compliant lubrication by default, the gripper can also be used in medical and pharmaceutical applications or in the food industry.
The proven, premium sector PGN-plus-P also sets the bar very high for pneumatically driven universal grippers. The performance features of this benchmark gripper are considered to be in a class of their own worldwide. Users can select the appropriate gripper for their specific applications from 189 standard variants or customize it thanks to the extensive range of accessories. Due to the patented SCHUNK multi-tooth guidance, this gripper series enables high torque absorption. The integrated permanent lubrication means that the PGN-plus-P is maintenance-free for life. A wide range of sensor systems enables specific data and status queries and extends the possible applications of this series.
The gripper for small components MPG-plus is already widely used in assembly automation. It handles small components and impresses with short cycle times and very compact external dimensions. In many automation cells, a whole series of these compact modules are active at once – so the user can utilize their system efficiently and achieve the greatest possible output. Particularly in the electronics industry, where small components have to be handled in large quantities and in the shortest possible time with absolute process reliability, the MPG-plus is the gripper of choice. Optionally, it can be equipped with a protective cover and is therefore ideally suited for use in life science applications.
The new long-stroke gripper PLG takes on the really big tasks: SCHUNK presents this pneumatic two-finger parallel gripper with a long jaw stroke, high gripping force, and profile rail guidance separately from classic catalog components. With the PLG, users get a state-of-the-art gripping module that becomes an application-specific gripper thanks to a wide range of variants and options as well as individual configuration. Using a license-free and browser-based web tool, the customer can quickly and easily configure their individual long-stroke gripper without having to use their own CAD program. The CAD data and a configuration-specific data sheet are available at the push of a button. With this tool, SCHUNK reduces the design workload and provides immediate information on price and delivery time. The gripper is available in two finger versions; in addition to the basic variant for short finger lengths, a variant for finger lengths of up to 800 millimeters can also be configured if the requirements are met. The stroke per jaw can be configured to customer specifications between 100 mm and 400 mm per jaw with millimeter precision.
SCHUNK provides the PLG with a pre-assembled pressure maintenance valve with hose for temporary force and position maintenance in case of loss of pressure. Due to the external attachment of up to ten inductive proximity switches on up to four gripper sides, a corresponding number of positions can be monitored. Alternatively, the stroke of the base jaw can be monitored via integrated IO-Link monitoring. Here too – as with the PGL-plus-P – the sensor can be used for position monitoring and workpiece differentiation.
In handling processes, pneumatic gripping modules combine high productivity with process reliability and long service life even under demanding conditions. SCHUNK has more than 30 series of different pneumatic grippers in its portfolio – a huge variety in all sizes for the full range of industrial applications. With sound planning and requirements analysis, every user can find the right gripper for their task, making their application cost effective and future-proof. With the SCHUNK design tool for grippers, it is easy to find exactly the right gripper for any application from the entire gripper portfolio – from the premium segment with the best performance data for special applications such as O-ring assembly to the economy segment and more simple designs. The focus is always on the specific application and customer requirements.