What is an end-effector and how do they work?

January 24, 2024
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What is an end-effector?

An end-effector is the device at the end of a robotic arm that interacts with the environment. It’s the working end of the robot.

End-effectors allow robots to do almost anything a human can do with tools, and sometimes even more. 

They’re also application-specific, so you may swap the end-effectors on a robot in an assembly line to achieve different tasks. This gives robots an unparalleled ability to be flexible and handle all sorts of different things. 

What types of end-effectors are out there?

End-effectors come in a huge variety of shapes, sizes, and capabilities. 

The most common types are:

  • Grippers: Grippers are designed to grasp and manipulate objects. They can have multiple fingers for delicate grasping or simple parallel plates for picking up boxes and other regularly shaped items. Vacuum grippers use suction to grab smooth, non-porous surfaces.
  • Clamps: Clamps are similar to grippers but are typically used to firmly and securely hold an object in place. Pneumatic clamps are often used in industrial automation.
  • Tools: End-effectors can also come in the form of popular tools like screwdrivers, welders, or spray painters.
  • Sensors: Some end-effectors incorporate sensors to provide feedback to the robot. For example, a gripper may have tactile sensors to determine how firmly it’s grabbing onto an object. Force-torque sensors can measure the forces and torques applied during manipulation.

The specific end-effector used depends entirely on the application you need them for. A robot that’s designed for delicate electronics assembly will need a very different end-effector than one used to move heavy pallets in a warehouse.

How do end-effectors work?

End-effectors typically attach to the robot wrist using universal mounts, like the M4 and M8 pins, that provide power and control signals. 

The robot's control system then coordinates the movement of its arm and wrist to position the end-effector as needed.

Let’s boil these end-effectors down to their component parts:

The jaws, or the part that grabs

The gripping parts of a gripper are the jaws or “fingers”, and come in various layouts. 

  • Angular: Resembles tools like pliers or alligator clips.
  • Concentric: Jaws form an arc around a central space, much like a human hand.
  • Parallel: Jaws align and move in unison, similar to the functioning of a wrench.

The different ways of interacting with objects

  • Impactive: These are the most commonly used type of grippers.
  • Ingressive: These grippers penetrate the object, similar to how a needle goes through fabric.
  • Astrictive: Use magnetic or suction forces for handling objects.
  • Contigutive: These ones use adhesion methods such as glue or freezing to secure objects, rather than physically lifting them.

What the jaw is made out of

When we’re talking about impactive grippers, jaw material is extremely important. While rough materials may be OK for handling wood or metal, for delicate tasks like packaging iPhones, softer materials like rubber are essential to avoid damage.

What powers the gripper?

The gripper’s actuation method or power source is important: you'll typically come across electric, pneumatic, and hydraulic options. 

Electric actuation: Most widespread, using motors and servos for precise control. Excellent for tasks requiring accuracy or a gentle touch, but may result in larger grippers, a potential issue in space-limited areas.

Pneumatic actuation: Known for fast movement and strong grip force. Less appropriate for delicate handling due to its dependence on compressed air.

Hydraulic grippers: A+ in heavy-duty tasks, such as those in car manufacturing, by leveraging compressed fluid for significant gripping power. However, they do not match the speed of pneumatic grippers or the gentleness of electric ones.

A matter of power

It's important to match the actuation power with the task at hand - for example, holding a microchip doesn't require much force, but a robot arm lifting 15 kg pallets does. 

Also, remember that the gripper counts towards the robot’s total payload capacity!

Additionally, grip force is super important - both maximum and minimum. The gripper suitable for lifting a heavy alloy might not be well-suited for gently picking up fragile parts 

For delicate tasks, a "compliant gripper," designed for specific objects and soft force applications, might be necessary, especially in crowded settings where an expensive force feedback system isn't exactly feasible.

What can end-effectors do?

End-effectors can perform an incredible array of tasks.

 Here are just a few of the things they can do:

“Pick it up, put it down”

The most basic function of an end-effector is gripping and grasping objects – as you’ve probably surmised from their name.

Vacuum grippers can pick up smooth, flat items like glass sheets. Mechanical grippers with multiple articulated fingers are perfect for grasping irregularly shaped objects.

Some end-effectors even have interchangeable tooling like suction cups, electromagnets or adhesive pads for picking up diverse materials.

Drilling and machining tasks

End-effectors equipped with drill bits, cutting tools or abrasive wheels can machine, cut, grind, and finish parts. 

Robotic arms have the strength and precision to perform these tasks fast and accurately. Machining end-effectors allow robots to take over many hazardous or tedious jobs, like CNC machine tending.

Painting and spraying

End-effectors with spray nozzles or paint guns can coat, paint, and finish surfaces. Robotic spray painting is very common in automotive factories to apply an even coat of paint over the entire surface of a vehicle. 

Robotic spray painting produces a high-quality, uniform finish and helps reduce waste and overspray. We know people try, but sometimes they get the jitters. 

Joining and welding all day long

Some end-effectors are outfitted with welding torches, allowing robots to perform welding tasks like arc welding, gas welding, or spot welding. 

Plus, robotic welding helps address the sadly increasing shortage of human welders

Quality control and inspecting

End-effectors equipped with sensors, cameras and scanners give robots the ability to inspect parts for defects or measure dimensions.

This type of robotic inspection helps improve quality control and ensures accurate, objective part evaluations, with the same care given to every piece, all day, every day.

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How much do end-effectors cost?

End-effectors can vary wildly in price depending on their complexity and capabilities. 

Your basic grippers typically start around $500 to $5,000. These provide basic grasping and pick and place functions.

Now, more complex end-effectors, like those used for machining, welding or assembly applications, can set you back between $10,000 to $50,000 or more. 

If you’re looking for highly customized or application-specific end-effectors, especially those used in high-precision or regulated industries, they may break the bank at $100,000 or higher.

Something else to keep in mind is that the specific components, materials, and technologies used in an end-effector also have an impact on its price. 

An end-effector made of durable, high-performance alloys and plastics tends to cost more than basic models.

On the same note, end-effectors with integrated sensors, pneumatic or hydraulic actuators, and complex control systems are typically on the higher end of the price spectrum.

Many end-effector manufacturers, like OnRobot, offer a range of “off-the-shelf” models at lower price points as well as custom design services for specialized applications.

Summing up

This in-depth look at end-effectors and how they function as an integral part of many robotics systems today is not something we did on a whim. 

We know end-effectors make robotics solutions possible across countless industries. And, coupled with now-affordable robotic solutions, they’re allowing small and medium businesses to have access to the big leagues – maybe for the first time ever. 


Why use an end-effector?

Once you have your robot setup with an arm, wrist, and hand, you'll need an end-effector to actually interact with the world. 

End-effectors, also called end-of-arm tools (EOAT), are the interchangeable devices attached to the end of a robot arm that perform a specific task like gripping, welding, painting, etc.

What are the standard end-effectors?

There are a few standard connectors for attaching end-effectors to robots, the most common being the ISO 9409-1-50-4-M4 and ISO 9409-1-50-4-M8 pins. These allow end-effectors to quickly attach and detach from different robot arms.

What are the most common types of end-effectors?

Some of the most common types of end-effectors are:

  • Grippers: Used to grab and move objects. Can be simple two-finger grippers or complex multi-finger hands.
  • Vacuum cups: Uses suction to pick up smooth, non-porous objects.
  • Tools: Things like drills, screwdrivers, welders, etc. that provide a specific industrial function.

What can end-effectors do? 

End-effectors enable robots to do almost anything a human with tools can do. They allow robots to drill, screw, weld, move pallets, assemble parts, and more. The specific end-effector you need depends on the task at hand. 

How much do end-effectors cost? 

End-effector costs can range from a few hundred to hundreds of thousands of dollars depending on their complexity. Basic grippers are on the lower end while highly skillful multi-fingered hands and specialized tools are much more expensive. 

Major manufacturers of end-effectors and grippers include OnRobot, Robotiq, Destaco, and SCHUNK.

Next steps

Regardless of your application, there’s likely to be an appropriate end-effector for it. But you’ll also need the right robot arm to get the most out of it

If you’re looking to find the perfect pairing of robot arm and end-effector for your application, RO1 by Standard Bots comes with a variety of grippers out of the box, universal M8 connectors, integration with OnRobot end-effectors and is the best choice for machine shops large and small:

  • Affordable: RO1 is the most affordable robotic arm in its class, starting at almost half the price of incumbent competitors. 
  • All-seeing: RO1 is equipped with best-in-class vision systems. Easy no-code programming makes it easy to detect the smallest of defects and imperfections.
  • Collaborative: RO1 comes equipped with safety sensors and built-in collision detection, for safe operation anywhere on your shop floor.

Speak to our solutions team today to organize a free, 30-day onsite trial and get expert advice on everything you need to deploy your first robot.

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