The Different Types of Robotic Grippers

24/05/2022



Collaborative robots, or cobots in short, are easy to integrate due to the cobots requiring less programming. Collaborative robots are a flexible tool that improves production diversity and versatility.

As we have mentioned before, an effective collaborative robot ecosystem is important not only for the overall safety of the work station, but also for the proper functionality and longevity of the collaborative robot. That being said, when it comes to cobot grippers, there are a variety to choose from depending on the task that fits your production needs.

Naturally one would want to maximise the level of efficiency and productivity in the manufacturing capacity.

Therefore understanding the range of grippers that currently exist on the market is important before deciding which is appropriate for your needs to ensure the success of the robots manufacturing capabilities.

Let’s get straight into it.


What is a gripper?


A gripper is a tool that is attached to the wrist of the collaborative robot.

Grippers receive their power in various ways, either from electrical to pneumatic (air), and hydraulic (hydraulic fluid). A gripper enables users to automate crucial manufacturing processes such as picking up and holding objects and also assembly.

As previously mentioned in “Introduction to Grippers”, there are four main types of grippers. These include:

Hydraulic grippers:


Hydraulic grippers are typically heavy-duty grippers that tend to apply forces needed to handle heavy items, usually 50kgs or more. The primary functionality of a hydraulic gripper is its gripping power. Given its ability to handle heavy items, hydraulic grippers tend to be used when there is a need for extra gripping force.

Vacuum grippers:


Vacuum grippers have suction cups. It is used to handle workpieces of irregular shapes or uneven surfaces. Vacuum grippers are often used in material handling such as flat or smooth components, and also palletizing applications.

Pneumatic grippers:


Pneumatic gripper in a nutshell, a pick-and-place gripper. It uses compressed air to function the gripper jaws, in other words also known as fingers.

Servo-Electric grippers:


Servo-electric grippers, also known as electric grippers, use an electric motor to control the gripper's fingers. A popular choice for many cobot applications including machine tending and pick & place.


There are a multitude of grippers that currently exist on the market, we will elaborate on each of the grippers to ensure that you can make an informed decision on gripper purchase.

Let’s explore them.


Angular grippers:


Angular grippers are robust, single or double acting grippers. Angular gripper jaws open and close around a central pivot point, either moving in an arching or sweeping movement. Often used when there is limited space or if the jaws need to move up and out of the way.

Parallel grippers:


How a parallel gripper works is that jaws will remain in perfect parallelism in all of the grippers movement either when opening or closing. Typically, parallel grippers are used in applications where the components will have a predictable shape.

Soft grippers:


Soft grippers are made of hyperelastic materials, instead of a rigid joint, which allows the gripper to deform continuously when it comes to contact with a component. This is dependent on the external or internal actuator that dictates the interaction with the component. Typical applications for soft grippers are delicate tasks.

Magnetic grippers:


Magnetic grippers, as the name suggests, uses a magnetised surface to hold or grab metal components. Magnetised grippers do not have fingers or jaws, instead it has a smooth magnetic surface used for applications such as handling sheet metal.

Adaptive gripper:


An adaptive gripper is a simple and flexible gripper. Often adaptive grippers possess multiple fingers made from soft materials. The overall design allows for gripping irregular, round, and/or delicate objects. This means that an adaptive gripper can adapt to various shapes of components and still have a strong grasp on the component.

Jamming Gripper:


Jamming grippers are made up of a flexible membrane filled with a granular material that can adapt to the shape of the component. By utilising and adjusting the air pressure within the membrane, the gripper can adapt to the grip of the object even when it's varying between shape and size.

Mechanical Gripper:


A mechanical gripper uses its mechanical operated fingers to grasp components.


(This is explained in-depth in another article Cobot End of Arm Tooling (EOAT): Most Common Types and Applications)

Advice:


It should be taken into consideration that grippers with smoother edges rather than sharp edges would potentially drastically reduce any probable harm. This will also affect the collaborative robot risk assessment, which would need to be completed with appropriate measures effective prior.

Conclusion:


As mentioned above, there are an array of grippers that are available to you, understanding each of them is important to fully maximize your robot investment.


To learn more about Grippers.


Updated 08/06/22