How to Choose the Right Collaborative Robot Gripper?

12/04/2022

What is a collaborative robot gripper?


A gripper is a tool that is connected to the wrist of the collaborative robot. This device allows for the cobot to take on an array of tasks most commonly picking up objects and holding objects.

In other words, it is just as similar to the human hand. Grippers are placed at the end of the arm of the collaborative robot.

What kind of collaborative robot gripper exists?


Hydraulic grippers

Hydraulic grippers are best for tasks that require massive amounts of force. These grippers draw their strength from pumps that can supply up to 2000 psi. Hydraulic grippers are essentially heavy-duty grippers that tend to apply forces needed to handle heavy items, usually 50kgs or more. But not everything is great about them.


Advice:


The oil used in the pumps makes the usage messier. The need to spend more on maintenance due to the grippers receiving damage often due to the amount of force the grippers apply.


Electric grippers

Electric grippers, also known as servo-electric grippers, use an electric motor to control the gripper's fingers.

Newer vacuum grippers run on electricity. It makes them slightly less powerful than their hydraulic counterparts, but it also makes them more user-friendly. Electric grippers are a popular choice for many cobot applications including machine tending and pick & place.


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. These fingers, similar to human fingers, aid in holding, grasping, and releasing work components.


Adhesive grippers


Adhesive grippers provide the best of both worlds.They are incredibly lightweight and can be used to pick up flexible objects, whilst on the other hand, they don’t rely on a power source, decreasing their running costs.


This comes to the main point of the article -

How to choose the right collaborative robot gripper for your needs?


There are a multitude of factors to consider when choosing the right gripper, but one sticks out very prominently - the designated application. Apart from this, there are a range of important things to evaluate when picking a gripper.


The overall task:

  • Will the gripper be handling only a single item or a variety of items?

  • Will the gripper be handling food items, electrical components, hazard material?

  • The payload the gripper will be handling?

  • Employing the gripper to operate in tight spaces?

  • Require data feedback from the gripper?


The cycle time:

  • The speed required for clamping and/or opening/closing the gripper will decide the cycle time.


Advice:


Robot specifications for maximum acceleration are calculated by the sum of the gripper weight and the part, so more gripper weight means less weight from the part you handle.

The precision:


For certain assembly works, this will require greater precision, which would mean a mechanical gripper would be more fitting - ideally one with servo-electrical motors.


On the other hand, component sorting functions would require adaptability, a gripper that can ensure parts to be sorted. It would be advantageous to one that ranges in sizes or rather can be positioned differently from each other.

Work-environment advice:


Some things to note when considering cobot grippers are:

  • Food and pharmaceutical industry - hydraulic grippers are prohibited due to the risk of oil spillage and contamination.

  • Clean room industries - vacuum and pneumatic grippers are not ideal given the possibility of creating flow of particles in the air.

  • Grippers used in surroundings that are exposed to dirt and particles, the grippers must be protected.

  • Corrosive or toxic environments in nuclear or chemical industries also create special considerations for protecting the gripper to ensure its stability and safety of use.


The components:


Understanding the components that make up the gripper is important to engaging with what is the right gripper for your needs.

  • Size: The gripper must allocate enough reach to handle parts but not in excess since longer fingers create more torque on the tool and the robot.

  • Weight: The gripper must be able to meet the weight of the component as well as the time of acceleration whilst performing the designated process. This does not mean to use the maximum clamping force, this will lead to damage to the component or possibly the gripper itself.

  • Surface type: In order to gauge friction, the understanding of what kind of grasp will be exerted with each surface type is important.


To learn more about Grippers.


Updated 18/05/2022