What is a 4-axis robot?

June 12, 2024
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What’s unique about a 4-axis robot?

A 4-axis robot is an articulated machine with four joints that provide movement in multiple planes. If you want automated equipment handling complex tasks with precision, a 4-axis robot is a great pick.

What are the components of a 4-axis robot?

A 4-axis robot typically consists of a few main parts:

  • Manipulator: The manipulator is the mechanical arm that provides movement. It’s made up of rigid links connected by joints that rotate and extend to position the end-effector.
  • End-effector: The end-effector is the "hand" at the end of the arm that grabs and manipulates objects. It can be a simple gripper to pick up boxes or a more complex assembly for intricate tasks.
  • Drive components: The drive components provide power and motion to the joints. Motors, gears, belts, and cables are commonly used to move the internal links and arm.
  • Controller: The controller acts as the brain of the robot. It coordinates the movement of the motors and manipulator to position the end-effector. Programming the controller allows the robot to perform automated movements and tasks.
  • Power supply: An electrical power supply provides energy to power the motors, controller, and any other components. Most 4-axis robots use standard AC power, but some can run on DC batteries.

Operational mechanics: How does a 4-axis robot work?

Basically, a 4-axis robot can move in three directions: up/down, left/right, forward/backward, and rotate — a total of four degrees of freedom. Each joint gets power from an actuator (like an electric motor) that gives the necessary force and torque to move and lift the robot arm. 

Also, the joints typically allow 180 degrees of motion for maximum flexibility and range — although the range can vary depending on the robot’s design. 

But how do these robots even feel their way around? 

Sensors on the robot provide feedback about the position and movement of each joint. The robot uses this information to precisely control the arm and ensure smooth, accurate movement. Of course, more advanced robots may use machine vision or other sensors to detect the environment around them and navigate on their own.

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Key uses and applications of 4-axis robots

All 4-axis robots are versatile and flexible enough for various industrial applications. 

Rocking it at the assembly line 

A 4-axis robot is very good at assembling components with multiple parts. Their skilled end-effector can grab, orientate, and join parts accurately. Automotive, electronic, and medical device assembly often use 4-axis robots.

Handling materials with ease

4-axis robots frequently unload, transfer, and organize materials on production lines or in warehouses. As for lift capacities, they can vary widely by manufacturer and application. Some models have smaller payload capacities (2 to 20 kg), while heavy-duty industrial models can lift hundreds of kilograms. 

Inspecting things 

Most 4-axis robots equipped with cameras and sensors are excellent for inspecting products. They can rotate, tilt, and pan sensors over parts to examine all surfaces. Automated optical inspection using 4-axis robots improves all-around quality control.

Packing it in 

All 4-axis robots are commonly used for packaging products by grabbing, orientating, and loading items into boxes, crates, or pallets. They handle packaging at super-high speed while minimizing product damage. Food, drink, and pharmaceutical packaging frequently use these bots.

Advantages of 4-axis robots

4-axis robots have quite a few benefits over standard robotic arms. 

Let’s take a look: 

  • Much more dexterity: With four joints, these robots can maneuver in tight spaces and at difficult angles that aren’t possible with typical three-axis models. 
  • Greater carrying capacity: Because 4-axis robots are more stable and rigid, they can lift heavier loads without compromising performance. While you can see some heavy-duty four-axis robots lifting up to 500 kg, it’s more common to see robots lifting in the range of 10 to 20 kg. 
  • A more expansive workspace: The extra joint expands the robot’s workspace, enabling it to reach over, under, and around obstacles. Since 4-axis robots can access a full hemisphere of space, they have a larger range of motion.
  • Easier to program: While 4-axis robots are more complex mechanically, they are not necessarily more difficult to program. In fact, their additional flexibility can simplify programming for some applications by reducing the number of steps required to manipulate an object or navigate obstacles.

Limitations of a 4-axis robot

Here are some limitations to keep in mind for 4-axis robots: 

  • A 4-axis robot has some inherent limitations in its range of motion. With only four joints, its movements are more linear and less articulate than robots with additional axes — such as six-axis robots. 
  • They have a fixed base. Unlike mobile robots, 4-axis robots can’t navigate or manipulate objects in a large space. They are best suited for repetitive tasks in a confined area, such as pick-and-place applications on an assembly line.
  • Some things they just can’t do. The restricted movement of a 4-axis robot may make it unsuitable for intricate assembly or handling of irregularly shaped parts. 

Is a 4-axis robot right for you?

A 4-axis robot can be a great solution if you need a flexible automation system for simple pick-and-place or assembly tasks. The additional axis gives you much more skill and range of motion compared to a 3-axis robot. This lets 4-axis robots access confined spaces and work with objects along multiple orientations. 

However, 4-axis robots are more complex to program and typically more expensive. They also require a larger footprint and consume more energy. If you need a robot for extremely basic automation jobs, a 3-axis or SCARA robot may be more your speed. 

Summing up

A 4-axis robot offers some cool capabilities but isn’t necessarily right for every situation. Only you can decide if the precision and flexibility of four axes meets your needs, or if you need more or fewer axes of motion.

Maybe you just need a simple pick-and-place application. Then 2 or 3 axes could work fine. 

But if you need complex movements and flexibility, 4 axes and beyond open up possibilities. Just weigh the higher costs and programming challenges against the dexterity. 

Next steps 

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  • Prioritize safety: With cutting-edge machine vision and top-of-the-line sensors, RO1 works seamlessly and safely alongside your team.

Contact us for a free 30-day trial and expert guidance on integrating RO1 into your shop floor.

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