Top Types of Grippers Used With Collaborative Robots (Cobots)

August 2022

The first collaborative robot was invented in 1996. This new concept was aimed at bridging the gap between the worker and a traditional robot, allowing them to work side by side.

Cobots have evolved substantially since the mid-90s and are a common piece of equipment in any manufacturing environment. Some of the top types of grippers used with collaborative robots enable them to do the most intricate jobs to high tolerances, which helps boost production capabilities.

There are numerous grippers for cobots which are adept for a wide range of functions, but it can be overwhelming when it comes to choosing the best one for the task.

In this article, we will look at the most popular collaborative robot grippers in manufacturing and summarise some of the top options manufacturers will have when selecting a gripper.

What Is a Collaborative Robot?

Collaborative robots, also known as Cobots, are the latest technology in robotics. They are changing the way manufacturers automate processes. This sub-group of robots differs, mainly because they are designed to work alongside humans, more like an assistant to their work, hence the name collaborative robots.

Cobots are fitted with sensors that allow humans and machines to exist in a small space. If the cobot senses that something is in its path and interrupts the signal sent out from the sensor, then it will automatically go into safe mode.

A cobot also allows employees to delegate monotonous or tedious repetitive tasks and free up their time to allow them to upskill or work on more creative areas in a company.

What Is a Gripper?

A gripper is a device that allows the robot to pick up, manipulate and hold an object. Grippers for cobots can enable manufacturers to automate essential stages of the production line, such as assembly, inspection, machine tending as well as pick and place.

Grippers in manufacturing work similar to a human hand in that they are located at the end of the arm. This allows users to have the strength of an arm twinned with the dexterity of a hand. A cobot can be used for heavy-weight tasks, such as stacking boxes, through to delicate electronic work.

There’s an abundance of different types of grippers for use with cobots. These range from human hand-like grippers; some even come complete with five fingers. Other times, a gripper may have just two or three fingers.

Grippers can also come shaped like claws or with large suction cups and air-filled bags, each designed with a different process in mind.

Types of End Effectors

If you’ve ever done any research into the different types of grippers, then you will probably come across the term EOAT. This means end-of-arm-tooling or the end effector. It essentially refers to any device at the end of the robot arm.

Grippers are a type of end effector. Other EAOTs can be cameras and welding tools.

The different types of grippers you’ll find in the collaborative robot market are:

• Hand-like grippers with flexible fingers
• Claw or hook grippers
• Suction cups, vacuum or pneumatic grippers
• Hydraulic grippers
• Specific 3D printed gripper
• Air-filled bags and cushions
• Magnetic or electronic grippers

Top Types of Grippers Used With Collaborative Robots

It can seem like a daunting task when it comes to choosing the correct gripper for a process. The most popular types of grippers used include finger grippers, vacuum grippers and magnetic grippers.

Each type of gripper can be distinguished between the power method and the control or dexterity of the gripper itself, with each gripper being suitable for different tasks.

Vacuum Grippers

Vacuum grippers work by using the difference between atmospheric pressure and a vacuum. They enable the gripper to lift, hold and move objects.

Usually, the vacuum flow is created by a miniature electromechanical or a compressed air-driven pump. You will need to ensure that the vacuum flow is uninterrupted to ensure that the cobot will be able to safely hold on to the object it has picked up.

The difference between electromechanical and compressed air-driven pumps is that a compressed air-driven pump delivers between four and ten times more power compared to its electromechanical counterparts. This makes the compressed air-driven pump the better choice if you need to lift heavy weights.

On the other hand, electromechanical-driven vacuum grippers excel when an application requires a high degree of mobility and dexterity.

Vacuum grippers are incredibly versatile and are used to automate a wide range of tasks. They are most commonly used in packaging and palletising operations.

Another advantage of vacuum grippers is that they are often a lower price compared to other types of grippers.

A disadvantage of vacuum grippers includes increased running costs, as they consume more power and often require external air supplies to generate a vacuum compared to other types of grippers.  However, electric vacuum grippers have their own in built vacuum pumps, which allows seamless integration with cobots.

Pneumatic Grippers

Pneumatic grippers use a combination of compressed air and pistons to operate their fingers or jaws. The most popular type of pneumatic grip is found in 2-finger and 3-finger configurations, although human hand-like models are also available.

These are some of the most versatile gripper tools and can perform a wide range of applications.

The advantages of using pneumatic grippers are that they are low cost and have a large range of grip force. They are highly suitable for operating in tight spaces and have a quick response time.

The disadvantage is that pneumatic grippers are only suited to handling single part types, so if your facility produces a lot of low volumes – high mix items, they may not be ideal. Another downside is that this gripper type provides limited force and position control compared to other gripper types, and they require compressed air to function. The requirement for compressed air also means that additional valving will be required, adding costs for hardware integration and programming.

 

Hydraulic Grippers

This type of gripper is powered by hydraulic fluids. Hydraulic grippers will provide more gripping power compared to a similar design with pneumatic control. This makes them ideal for heavy-duty applications.

One of the main advantages of hydraulic grippers is their excellent gripping power. A disadvantage is that they come with the added complexity requiring handling oil, a pump, and a reservoir. This can all lead to higher maintenance than other gripper types. These types of grippers may also be much heavier therefore limiting applications and uses with cobots.

Electric Grippers

Electric grippers are a popular choice when a cobot application is needed to pick and place. This type of gripper doesn’t offer the same degree of gripping power when compared to hydraulic grippers. However, they are more suitable for applications that require high-speed twinned with a light to moderate gripping force.

Electric grippers usually come with a two-jaw and three-jaw set-up. The three-jaw configuration is often the favoured choice for use with round or cylindrical objects, and the two-jaw can be retooled to suit any other type of application.

One of the most defining features of using electric grippers for manufacturing automation is the control. The majority of electric grippers come with built-in microprocessors, which can enable the user to vary gripping force, speed and opening sizes to allow the same unit to be used on different products. This allows an electric gripper to easily handle a wide range of different part types. The introduction of more technology within these grippers also means that the “brain power” with these units can accurately measure distance, therefore providing a means to pick components up and measure them at the same time.

 

Electric grippers are ideal for cobot applications, providing seamless integration to the cobot control system.

A disadvantage of electronic grippers is that, in general, they tend to provide less gripping power compared to pneumatic grippers. From a cost point of view, they can also be more expensive.

 

Choosing the Correct Robotic Gripper

When it comes to choosing the correct gripper, there are several factors you should keep in mind. The most important characteristic will be what you’re going to be using the gripper for.

However, there are still some other important questions you’ll want to consider when selecting a gripper for your cobot:

• What will the gripper be handling? Single items or a mix?
• What types of items will be handled by the cobot?
• What shape, size and weight are the items that you need the gripper to handle?
• Do you need the gripper to have an integrated data feedback system?
• What space will the gripper need to operate in?
• How will the gripper be programmed?

 

Cobot Software and Grippers

One of the advantages of cobots, compared to robots, is that the setup is much more intuitive. Your cobot will come with user-friendly software and a variety of applications. Some can even be controlled through a smartphone.

Once you have decided on the correct gripper and installed it, you will be able to program a range of tasks.

Your collaborative robots will be able to learn new moves, as well as be manually moved into needed positions. These can be stored in the software and used in the future.

Because a cobot will work with a range of grippers and are simple to program, they can be rapidly implemented across different teams and assigned to different tasks quickly and efficiently.

 

 

Need More Information on Grippers?

Since 1984, SP Automation & Robotics has provided bespoke automation machines to a wide range of industries in the UK. We have experience working with small-scale start-ups right through to large, international businesses.

If you’re still unsure what the top types of grippers are used with collaborative robots for your business, then speak to one of our in-house experts, who will be happy to answer all your questions. We pride ourselves on providing a top-class service from initial concept and installation through to after-sales support.

Contact the team today to arrange a visit or to discuss your enquiry.

 

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