Robotic grippers comprise the most popular category of EOAT for robots. They are a cost-effective option that allow for the handling of a variety of parts. Grippers are fitted to the end of a robot arm and are considered their mechanical hands as they allow for handling, tightening, grasping, and releasing of objects. Gripper end-effectors are commonly integrated with industrial robots in order to perform material handling, packaging, palletizing, pick and place, and machine loading and unloading applications.
Gripper TypesGrippers are available in a variety of options and selecting the best one greatly depends upon the application type and objects being handled. Some of the most common grippers include:
- Mechanical Grippers - These grippers consist of two or more fingers or a claw type of clamp. The points of contact on a mechanical gripper can be covered with soft friction material to reduce damage to objects being handle. Two finger grippers are more common since they are capable of handling most objects and have a simple design. Three or more finger grippers may consist of adaptable, soft rubber fingers to allow for the manipulation of sensitive objects such as food. Claw style mechanical grippers are typically integrated with heavy payload robots, like the FANUC M-900ia/350, for palletizing applications. Mechanical grippers can operate in parallel or angular movements. With parallel grippers the two fingers close parallel to the workpiece in order to grasp it. While angle grippers grasp workpieces at various angles including 30, 40, or 80 degrees by rotating the fingers around an axis. These grippers are best for larger or oddly shaped objects since they can be adjusted. Angle grippers can also function in tight spaces, but parallel options cannot.
- Vacuum Grippers - Vacuum grippers are the most popular of the gripper types due to their versatility and ability to handle numerous objects, including those that are delicate. These grippers work best on non-ferrous materials and use suction cups consisting of air tight materials, usually either rubber or polyurethane. Air pressure is applied to the suction cup allowing it to grab and lift an object. Air pressure provides flexibility with the ability to adjust the amount of force applied to the object being manipulated. In the food industry the use of soft pouches are becoming more common for food packaging, which is why this industry favors the integration of robots like the FANUC M-710ic/50 with vacuum grippers to prevent damage to these items while being handled.
- Magnetic Grippers - When it comes to handling ferrous materials magnetic grippers are often utilized as these materials allow for a magnetic attraction. Magnetic grippers can handle a variety of part sizes and shapes including those with holes. They are a popular option in the automotive industry for material handling, palletizing, and bin picking applications since they can grab objects quickly. For example, a ABB IRB 6640-205/2.75, can be fitted with a magnetic gripper in order to palletize metal paint containers. Magnetic grippers are more limited than other types since they can only be used with metals. They also require a clean surface area as dirt, dust, or grim can interfere with the magnets lifting strength.