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Multi-axis robot: How many axes do you need?

Multi-axis robot: How many axes do you need?

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Dec 15,22

People often consider using multi-axis robots in their manufacturing processes. In this article, Emily Newton takes a closer look at how to choose the number of axes for a robot.

Multi-axis robot: How many axes do you need?

When people consider using robots in their processes, they often consider multi-axis robot options. A robot axis represents a degree of freedom. Thus, the ways in which a robot can move go up with the number of axes. Here is a closer look at how to choose the number of axes for a robot.

Determine the kind of movement necessary

A good starting point is to consider how the robot must move to carry out its tasks successfully. For example, a three-axis robot can move in the X, Y and Z axes but cannot turn or tilt.

Pick-and-place robots are common examples of three-axis machines. However, people must plan the workspace so the robot can grab a part and then drop it in the correct spot without turning.

A one-axis robot can only move from left to right, but a two-axis option can also go up and down. Then, adding axes allows a robotic arm to do things like rotate its wrist or change the orientation of an object it holds.

If the robot must move across several workstations or otherwise handle long distances, a seven-axis model is often a feasible solution. People mount six-axis articulated robots on transfer units that act as the seventh axes. That approach allows the machines to move more freely than six-axis types can. It’s even possible to attach multiple robots to one transfer unit but control them independently.

Having more axes is not necessarily better. For example, someone might need a robot to lift heavy objects. In such cases, limiting the machine’s range of motion can provide greater stability.

Assess the work area

The environment where the robot will work is another critical consideration. The machine’s reach represents how far the robotic arm extends when fully outstretched. The robot’s overall range of motion is one indicator of its total reach. For example, if the machine has limited movement, its reach will be comparatively smaller, too. That’s the case even if the robot is a large model.

As people determine where to put a robot in the work environment, they must consider how close employees will be while the machine operates. It’s also necessary to evaluate the positioning of any surrounding equipment, so the robot is not at risk of hitting it.

Being mindful of traffic flow and the number of occupants typically in the area at a given time is also useful when assessing a robot’s reach and — in turn — its axes. Robots and humans can work safely in shared spaces, but only when the responsible parties take time to minimize risks.

Moreover, it’s challenging and sometimes impossible to add axes to a machine after the fact. Thus, if the work area is a major consideration impacting the number of axes, the preferable option is probably to rearrange it rather than compromising by getting a robot with a reduced range of motion.

Consider the robotic technology budget

One thing to consider is fewer axes can mean a less expensive robot. When the range of motion is not as extensive, the associated price tag for the machine may be lower, too. However, the lower price may only relate to the more reasonable upfront cost, which is why it’s necessary to have a long-term viewpoint.

People don’t always realize a multi-axis robot can sometimes save them money. For example, choosing a seven-axis robot rather than a six-axis one can result in a better distribution across each axis, helping the machine have a longer life span.

A thorough robotics budget should include maintenance and repair expenses, along with the costs required to buy the machine at the start. Another thing to think about is how much the robot will save time or fit into the business's goals.

One robot used within a project at the University of Ottawa is a six-axis arm that researchers program to simulate how people move when walking or climbing. The hope is for medical professionals to learn things from the robot that make orthopedic surgeries more successful.

Discuss the desired application

Knowing how people will apply the robot to the overall workflow helps determine the number of axes needed. Decision-makers should think about any current obstacles or growth inhibitors when envisioning their future robots. Perhaps the machine they buy will help them become more competitive or boost their factory’s output.

Many robots used in industrial facilities are six-axis models, giving them the flexibility needed to handle various tasks. For example, that range of motion allows a gripper to reach anywhere inside the work radius. This kind of multi-axis robot is an ideal solution if the workpiece is at an orientation other than parallel to the robot’s base.

Knowing how a company wants to use a multi-axis robot now and what the business might do in the future helps shape conversations about designing a custom machine or selecting the right robot from available commercial offerings. It’s also valuable to consider which workflows are currently the most error-prone or otherwise problematic. How might a robot improve those weaknesses?

A multi-axis robot could make a big difference to the workflow

A multi-axis robot is not the best solution for every workplace. But, when decision-makers take the time to assess their needs and learn how a robot could improve the current situation, they’re highly likely to reach beneficial conclusions.

About the author:

Emily Newton is a tech and industrial journalist and the Editor-in-Chief of Revolutionized Magazine. Subscribe to the Revolutionized newsletter for more content from Emily.