A robot grippers is an electrical end of arm tooling device that manipulates objects using the end of its arms. It has a device with a controllable hand that grasps and releases a wide variety of materials and parts through an automatic process. Most robot grippers have mounting surfaces with high precision for attaching the finger tooling device and gripper to a robotic arm.
The key significant advantages of using a robot gripper is reducing part damage during production and packaging. Arm tooling devices end come in contact with the products. Hence, it’s essential to pick the most appropriate kind of gripper for company’s operation.
Grippers are powered by electricity, vacuum or compressed air. This partly makes up the four categories of robotic grippers; vacuum, hydraulic, pneumatic and servo-electric grippers. If you want to select the best robot gripper for your company, it is best to choose a gripper based on its handling application and the material used in its manufacturing. Let’s review the four categories of grippers and some of the most common types of grippers available today.
Categories of Grippers
- Vacuum Grippers
These are the standard end f arm tooling devices in the manufacturing industry because of their high level of flexibility. These grippers use a polyurethane suction cup or a rubber to pick up items. A few vacuum grippers use a closed-cell foam rubber rather than a suction cup for picking parts or materials.
- Hydraulic Grippers
These type of grippers is ideal for operations that need lots of force. They have a lot of strength which is generated from hydraulic pumps which can offer up to 2000psi. On the other hand, however, these machines are messy because of the oil from the pumps. They also require frequent maintenance because the gripper gets damaged often due to the high force used during the application.
- Pneumatic Grippers
These grippers are well known for their lightweight and tiny size. The compact size makes it ideal for places with limited real estate, such as small manufacturing companies. Pneumatic grippers can be closed or open. They are often referred to as “bang-bang” mechanism due to the noise created during the operation.
- Electric Grippers
These types of grippers are easy to control, so they are more suited for industrial settings. Electronic motors enable the movement of the robot gripper. These are highly flexible grippers. Their flexibility accommodates different material tolerance when they are handling parts and materials. They are also clean and relatively cost-effective.
Common Types of Robot Grippers
- The Three-Jaw Robot Gripper
These end of arm tooling devices are available in angular and parallel variants. They are commonly used for picking up material and parts through a cylindrical surface. As the name suggests, the three-jaw robot gripper has three jaws with 120 degrees space between each jaw. The jaws of this robot gripper move in unison. It provides a secure grip of the part by centring it during its closing or opening motion,
- Bellows Robot Gripper
This type of robot is designed to grip objects with a cylindrical surface. It uses an elastomer bladder to grasp the part. Compressed air inflates it, making it expand and grip the cylindrical part. It is also designed to release the part when the compressed air is released, and the bladder deflates.
Collet and Expanding Mandrel Robot Gripper
This end of arm tooling device is also designed to grasp cylindrical surfaces. However, it utilizes a linear motion and a wedge shape to open or close its metallic fingers to grip the I.D. or O.D. of the part firmly.
- Parallel Motion Two-Jaw Robot Gripper
This is one of the simplest grippers that is utilized in many applications. It comes in Pneumatic, electric and hydraulic versions and a large variety of sizes, weights, forces, and stroke ranges. They are commonly used to grasp parts with two parallel flat surfaces. They grip parts using either the closing or opening motion. The parallel motion two-jaw robot gripper also has an angular two-jaw version with 90-degree pivoting fingers.
- O-Ring Robot Gripper
This robot is specially designed to handle O-ring seals. It operates similarly to a three-jaw parallel gripper. Its six or eight fingers radially expand and grab the inner diameter of the part or material. Once it is stretched, the O-ring is placed into a groove at the end of the shaft.
- Needle Robot Gripper
This variant of robot gripper is rare. It is designed to pick up woven sheets or porous materials like textiles by piercing through the surface with multiple sharp needles.
- Multi-Finger and Adaptive Robot Gripper
This is a recent robot model designed to enable robots to grasp various products that could previously not be manipulated. This robot grips irregular, spherical or soft objects and gives the controller force feedback to prevent damage to the parts or materials.
- Advances in Robot Grippers
As the application of robot grippers increases in e-commerce, manufacturing, and place applications, there has been a demand for robot grippers with enhanced capabilities, especially collaborative robots that can handle a wider variety of objects and perform more repetitive tasks. Some of the demands for advanced characteristics of robot grippers include:
Future robot grippers should consider the required precision for performing a particular task. The grippers must be accurately sized or programmed to handle the size, hardness and weight of the moved items. Some companies have already begun offering customizable end effectors for specific materials.
Robot Grippers with Improved Dexterity
The addition of axis and enhancement of torque sensors have enhanced the intelligence of movement grippers and the capabilities of the robots to manipulate fragile objects, especially when the robots work close to Humans.
There are four types of robot grippers that you could use for production in your company; hydraulic grippers, servo-electric grippers, pneumatic grippers and vacuum grippers. Not all robot grippers may be suitable for your organization. When selecting a robot gripper for your company, select one based on the handling application and type of material your company is handling.