In order for industrial robots or collaborative robots to perform numerous applications needed in a production line, they need to have the right tooling and equipment. Fortunately, most robots and cobots can be equipped with various tools – with the one most often used being grippers. But what are grippers exactly, and what different types are there? In this article, we attempt to break down and explain the types of grippers used in manufacturing, and how they work. Keep reading on to learn more about this topic!

What is a gripper?

In its most simplest term, grippers are what allows a robot to pick up objects and put them down in another place. When combined with a robotic arm, these grippers allow manufacturers to automate important processes such as pick and place, assembly, inspection, machine tending, and more, to name a few.

If you are still confused, it may help to think of them like a human hand – grippers are generally positioned at the end of a robotic arm and combine the strength of the arm with the dexterity of a hand. This means that robots which may seem large and unwieldy at first glance can still be used to handle delicate tasks and objects, such as electronic components.

Grippers can come in a variety of shapes and sizes. These can include finger grippers (designed like a human hand with five fingers), mechanical grippers, claws, and even grippers with large suction cups. As a result, each gripper will have its own specifications such as its payload, gripping force, and gripping width – meaning you have to choose carefully depending on what task you want the robot to automate!

Types of grippers

Choosing the right gripper for your robot can be an overwhelming task, as there are so many grippers available to pick from. On the whole, though, grippers can typically be divided into a few main types, with each type having its own distinguishable and unique properties. We have listed and explained what they are below:

Pneumatic grippers

These types of grippers typically use compressed air in order to operate their fingers, which typically range from two to three. As a result, a pneumatic gripper tends to be more suited for less complex tasks. Another good thing about them is that they are often lighter, low-cost, and have a large grip force range. These grippers also have the ability to work in tight spaces, with fast response times. However, it is important to remember that pneumatic grippers are generally used to handle single-part types, meaning that they may not be a great fit for your production line if your company produces a lot of low-volume and high-mix goods. Fun fact, these grippers can be either opened or closed, which has earned them the nickname of ‘bang bang’ actuators, as a result of the noise created when the mental-on-metal gripper works.

Vacuum grippers

Vacuum grippers are generally considered the standard end-of-arm tooling devices in manufacturing as a result of their high level of flexibility. These grippers usually use the difference between a vacuum and atmospheric pressure in order to hold, lift and move certain objects. Often, the vacuum or vacuum flow is generated by using a miniature electromechanical pump or a compressed air-driven pump. It is important that the vacuum flow be uninterrupted so that the robot or cobot can safely hold onto the item that it has picked up.

Surprisingly, research has shown that compressed air-type grippers often produce four and ten times more power when compared to their electromechanical counterparts, which makes vacuum grippers fantastic at lifting heavy items. However, electromechanical grippers generally do better in tasks that require a high degree of mobility.

Some of the advantages of using vacuum grippers include having the ability to handle a lot of different items – even when those items have not been positioned well. They also tend to be cheaper compared to other kinds of grippers.

Electric grippers

Electric grippers are also popular for various cobot applications, especially for tasks such as pick and place as well as machine tending. While they tend not to offer as much gripper power when compared to hydraulic grippers, they are well suited to tasks that require light or moderate gripper force and high speed. They are also better suited for more complex tasks since people can better regulate them on other parameters.

Electric grippers usually come in two and three-jaw combinations. Three jaw grippers are often chosen when round or cylindrical objects need to be picked up.

On the whole, the defining feature of electric grippers remains their control. Most of them come with microprocessors that allow the people operating them to vary their gripping force and speed. Moreover, some of them are also outfitted with force sensors so that the gripper can easily handle a lot of different part types. However, they tend to be more expensive when compared to pneumatic grippers, which is something manufacturers should keep in mind.

Servo-electric grippers

These kinds of grippers generally appear more in the industrial setting, due to them being far easier to control. The electronic motors help to control the movement of the gripper’s jaw. The great thing about these grippers is that they are highly flexible, which allows them to have different material tolerances when handling various parts. Servo-electric grippers are also very cost-effective, due to being clean and having no air lines.

Hydraulic grippers

Much as its name suggests, hydraulic grippers are powered by hydraulic fluids. These grippers provide the most strength, making them suitable for applications that require a significant amount of force. As such, a hydraulic gripper’s main advantage remains its excellent gripping power. That being said, despite their strength, there are still a few things to be aware of. Firstly, hydraulic grippers tend to be messier than other grippers as a result of the oil used in their pumps. They are also a lot more complex to handle since manufacturers need to maintain a hydraulic gripper’s pump and reservoir as well. Secondly, these grippers may also need more maintenance as their gripper may become damaged as a result of the force exerted during their application.