The image of the cost- and maintenance-intensive industrial robot that moves car parts around in its safety zone is long outdated. Many modern robots are able to act collaboratively and work completely safely hand in hand with humans. Equipped with the right end-of-arm tooling (EoAT), they adapt quickly and flexibly even to variable production requirements. Modern EoAT has several features that facilitate the integration of the automation solution as a whole and lower supposed access barriers.

Whereas the implementation of a robot previously had to be accompanied by experts with advanced programming skills, modern EoAT is so intuitive to use that even employees without relevant expertise can quickly learn how to use it. This not only saves costs that would be incurred by hiring a programmer or specific training measures for the workforce; it also saves valuable working time, which is an advantage, especially in view of the rampant shortage of skilled workers.

Having robots take over repetitive and strenuous tasks also relieves employees and gives them more capacity for more demanding activities such as machine operation or strategic planning. These tangible benefits also increase acceptance of the automation project within the workforce. If employees are directly convinced of the positive characteristics of the robots, they are more likely to accept them and thus create the basis for a sustainable cultural change.

The VG10 vacuum gripper has two flexible arms that can be controlled independently of each other. Thanks to the adjustable suction power, it can handle a variety of objects of different sizes.

© OnRobot

Advanced EoAT can also be easily reprogrammed for different tasks. New developments such as 'Tool Changer' also enable the attachments to be changed quickly. This saves time that was previously spent retooling machines. One example of this is the Quick Changer from OnRobot. Positioned between the end effector and the robot arm, it releases the tool to be set down with just one click and positions the new tool to be inserted with an accuracy of 0.02 mm. With a dead weight of just 200 g, it hardly affects the robot's load-bearing capacity. Its compact size also enables a minimum distance from the tool center to the robot, which minimizes the load on the robot joints. With no sharp corners or edges, the Quick Changer also ensures safe handling. The same robot arm can now take on completely different tasks with the corresponding EoAT. This high level of flexibility is particularly useful in production environments where the order situation is constantly changing.

The fact that modern EoATs can be combined with robot arms from different manufacturers also creates advantages for users and system integrators. The gripping systems and sensors from OnRobot, for example, are compatible with robot arms from Universal Robots, Kawasaki, Kuka, Fanuc, Techman, Doosan, Nachi and Yaskawa. This gives users more combination options and allows them to choose from a wider range of EoATs.

Grippers become smart

Last but not least, EoAT can take on increasingly complex tasks. The RG2-FT gripper from OnRobot, for example, is able to both see and feel objects. This is made possible by an integrated proximity sensor, force/torque sensors in its fingertips and integrated application software. The RG2-FT feeds the data recorded by its sensors back to the robot arm, which then immediately adapts its movements accordingly. This enables the robot to determine the position of a workpiece even if its exact parameters are not known in advance. This is particularly advantageous when the robot is dealing with deformed materials or irregular workpieces.

Equipped with such a smart gripper, the robot arm can anticipate any slippage of the workpiece and ensure safe handling. It can also perform high-precision assembly tasks, such as the insertion of cylinder heads or the assembly of gearboxes. In other words, smart end-of-arm tooling opens up areas for automation that were previously reserved for humans - whether in electronics production, automotive manufacturing or mechanical engineering.

In a nutshell: modern EoAT lowers supposed automation barriers in various ways. On the one hand, it reduces the costs of the entire automation project and ensures a fast ROI by enabling a wide variety of activities to be performed with one and the same robot using the right peripheral products. The time saved during integration and retooling keeps the costs of dormant processes low, while the intuitive operation makes the involvement of external programmers superfluous. These features make automation affordable even for smaller companies.

Which gripper for which application?

• Collaborative robot arms and grippers are traditionally used for pick & place tasks. These include palletizing, packaging and machine loading. Collaborative two-finger grippers are generally recommended here. Individually adaptable fingertips or depth compensation make their use more efficient, as the grippers can adapt better to the task at hand and grip objects more precisely.

• To automate complex processes particularly efficiently, it also makes sense to use a double gripper: such models are able to handle two objects at the same time, which further reduces throughput times.

• In addition to weight and size, the shape of the objects to be handled is decisive. A vacuum gripper makes sense for large, flat objects such as solar panels, tiles or displays. In particular, models with adjustable arms and adjustable suction power are able to lift flat objects of different sizes and geometries. Models without an external air supply are also particularly space-saving and can be integrated more easily into the production layout.

• A vacuum cannot be generated for particularly sensitive surfaces or porous and holey structures. This is the case with drilled PCBs, for example. Adhesive gripping systems such as a Gecko gripper can provide a remedy here. When its gripping surfaces, which are coated with tiny hairs, are pressed down, Van der Waals forces are generated which enable it to lift objects without delay.

• In precision and fine assembly, end-of-arm tools must be able to perceive even the slightest resistance in order to correct their course in real time. Smart grippers with integrated sensors and corresponding software are particularly recommended for this purpose: The RG2-FT gripper from OnRobot, for example, has an integrated proximity sensor as well as force/torque sensors in its 'fingertips', enabling it to grip objects in a centered manner and thus insert valves into cylinder heads or mount manual transmissions, for example.

• Quality control also requires a high degree of flexibility, as grippers are regularly confronted with objects of different sizes. Only with the right sensor technology, such as force/torque or proximity sensors, is a gripper able to adjust the pressure applied in such a way that the object in question is not damaged.

• When treating surfaces - be it deburring, polishing or grinding - it is advisable to combine the necessary tools with appropriate sensor modules. This is because the main challenge here lies primarily in the precise metering and constant maintenance of the force required. In addition, the end effector must be able to follow the contours of the workpiece precisely. With force/torque sensors, such as the HEX models from OnRobot, a robot arm is able to do this even without complex programming.

Author:
Björn Milsch is General Manager DACH & Benelux at OnRobot.