Robotic Arms: Different Types and When to Use Them

05 January 2022
robotic arms
Catherine Bernier
Content Manager
,
Content for Cobot

Robotic arms are the most common form of robot technology in the industry. Read on to learn the benefits of this technology and see if it is right for you.

Robotic arms are one of the most identifiable pieces of robotic machinery in industrial settings. They tend to fascinate with their impressive feats of speed and strength, but their uses and how to apply them can be a mystery. This article will broadly describe the place of robotic arms in industrial applications to give you a better understanding of if they might be the right choice for you.

Topics discussed in this article include:

  • Types of robotic arms
  • Industries and Applications for robotic arms
  • When to (and not to) use robotic arms
  • Cost considerations

Types of robotic arms

The term “robotic arm” broadly describes a group of robotic mechanisms. These different robot types tend to have similar applications. However, each type has distinctions that typically lead to it being optimized for certain tasks over other robotic arms. Types of robotic arms include:

  • Articulated arm
  • Six-axis
  • Collaborative robot
  • SCARA
  • Cartesian
  • Cylindrical
  • Spherical/Polar
  • Parallel/Delta
  • Anthropomorphic

Articulated arms are general-purpose robotic arms with 5 or more joints or degrees of freedom. The articulated arm is an umbrella term for many other robot types. For instance, a six-axis robot is an articulated arm with six degrees of freedom. Articulated arms cover the broadest range of robot types used in industry and include six-axis and collaborative robots. You will find an example of this robot type in the banner image of this article.

Six-axis robots are the most common articulated arm. This also makes them the most common robotic arm used in industry today. Thanks to their flexibility, they are a great general-purpose robotic arm. This gives the six-axis an impressive list of uses. The six-axis robot is the most easily identified industrial robot.

The collaborative robot is a robotic arm purpose-built for hybrid work. This means it is designed to work near humans. Certain safety features allow for significant risk reduction in hybrid work environments. This is a relatively new robot type and its uses are still being explored. Collaborative robots are becoming more prominent in the industry as more manufacturers are being exposed to their benefits. The future is exciting for collaboratives. 

SCARA robots are selectively compliant robot arms. This means they don’t have the same flexibility afforded to articulated arms. This limits them in some respects but gives them certain advantages over articulated arm types. 

Cartesian robots are rigid systems that move around in a 3D coordinate plane. These robots are typically constructed of 3 linear actuators. One actuator moves left and right in the x-axis. An additional actuator is attached to the x-axis actuator. This actuator moves up and down in the y-axis plane. A final actuator is attached to the y-axis member and moves back and forth in the z-axis plane. Cartesian robots are positioned for small applications.

Cylindrical robot arms are designed around a single arm that moves up and down a vertical member. This vertical member rotates the arm horizontally. The arm can extend and retract to perform its task. These robots are very compact and are deployed for small and simple tasks.

The first modern industrial robot was a spherical (polar) robot. This robot type has a simple design that isn’t as common today as it once was. Spherical robots are similar to cylindrical robots except they swap the vertical linear axis with an additional rotary axis. This axis allows it to rotate vertically. It was designed for simple tasks that don’t require high speed or complex motion.

Parallel/Delta robots are high-speed options for robotic automation. These robots’ unique design allows them to reach incredible rates of speed. The delta robot is a great choice for high-speed and lightweight tasks.

Anthropomorphic robots are a rare sight in industrial settings. These robots boast two or more arms and a friendly face. They are often deployed in collaborative environments where they are working in near proximity to human operators.

Industries and Applications for Robotic Arms

SCARA_industrial_robot

 

The industries and applications for these robot types vary broadly. This is a testament to just how many uses there are for robotic arms in industry. Common industries include:

  • Aerospace
  • Automotive
  • Metals
  • Food and beverage
  • Pharmaceuticals
  • Plastics
  • Health sciences
  • Electronics

It is easy to understand that due to the wide range of industries the number of applications would vary greatly as well. Some of the most common applications include: 

The general-purpose nature of robotic arms allows them to be great choices for many applications regardless of industry. They strike a good balance between speed, payload capacity, reach, and precision. This allows them to perform effectively at many tasks. These features also grant manufacturers flexibility to repurpose these robots in different applications outside of their original intention. This can be more difficult for other robot types. The flexibility granted by robotic arms is certainly a value add for this robot type.

When to (and Not to) Use Robotic Arms

Uses_of_robotic_arms

 

Robotic arms have such a common place in industry due to their ability to perform most tasks well. There are certain features of applications that allow robotic arms to especially excel over other robot types. Some features of your application that might lead you to consider a robotic arm include:

  • High levels of dexterity are required
  • Large payload capacity and reach needed
  • Hybrid work environment

Dexterity is a hallmark design of articulated arm types. Applications that require a machine to twist and manipulate the product at odd angles can be a good match for robotic arms. Specifically, the articulated arms are like six-axis and collaborative. Examples of this type of application include robotic welding. This task often requires the robot to move at angles in several different planes. This is difficult to impossible to achieve for most other robot types. SCARAs are a robot type that can struggle here due to their selective compliance. So, this feature isn’t common across all robotic arms.

Robotic arms often have a good balance of payload capacity and reach while not sacrificing too much speed. This allows them to take on heavy-duty tasks that require both features. A good example of this is palletizing. The palletizing application often requires the robot to cover a wide range of motion to pick boxes and fill a pallet. Full boxes can be of considerable weight. This demands both strength and range which six-axis robots can often supply. Other robot types like delta robots lack the strength and range of motion to be able to perform these tasks at scale.

Hybrid work environments are unique challenges for robots. Robot technology poses certain dangers to human operators and traditionally must be sequestered from the outside work environment. Some applications require a human-robot mix to operate at peak efficiency. Collaborative robots are positioned to handle these types of applications. Material handling applications often deploy collaborative robot technology. This means a human operator can load raw materials into a staging area near the cobot while the robot handles the loading and unloading of the material into a machine. This loading and unloading might be dangerous for people. Removing them from the hazard creates a safer work environment. 

Are you unsure about which robot type is right for you? You can easily talk to one of our experts who can help you choose the exact robot type for your application based on your specific needs.

Cost Considerations

The cost of your robotic project has a direct impact on your ROI calculation and your bottom line. It is important to have a clear picture of your expected costs before taking on any robot project. Robotic arms are a broad family of machinery, so giving an exact range is an impossible task. However, we can give some context to your expected costs so you are more prepared with what questions to ask suppliers. The total cost of your robot project will likely include items like:

  • Robotic arm
  • End of arm tooling
  • Safety equipment
  • Installation costs
  • Integration costs
  • Maintenance costs

These costs can quickly add up. It is not uncommon to have a final price tag of around $100,000 USD for a moderately sized robotic arm project. It is important to understand these costs and the possible impact on your business to know if a robotic arm is right for you. Still not sure about your costs? Start receiving quotes for all of your proposed robot projects.