Choosing components for cobots

Published:  25 May, 2018

Behind the drawn factory doors of facilities across Europe and with the continuing march towards Industry 4.0, humans are working safely alongside a new kind of colleague; one that is stronger, faster and more efficient than ever before: collaborative robots. PWE takes a look at how to choose the right bearing for this new automation application.

Just a few years ago, collaborative robots were widely considered a novelty, but the technology has quickly grown to be one of the most significant trends in robotics. In fact, an ABI Research study predicts that industry will be populated with more than 40,000 collaborative robots by 2020.

As opposed to traditional industrial robots, which are confined to operate in work cells to protect human workers, collaborative robots can operate — as the name suggests — collaboratively with their human counterparts. They are designed to operate safely alongside people, by limiting the robots force and implementing sensors that prevent the robot colliding with a human or any other equipment.

The machines are used to carry out repetitive roles such as assembly and handling, taking these menial tasks away from humans to free them up for more complex tasks. As they are designed to take on these basic operations, collaborative robots tend to be much simpler than other industrial robots, making them cheaper to buy, easier to operate and less hassle to maintain.

Maintaining accuracy

Despite the simplification of their design, the specification of bearings for collaborative robots is just as important a consideration as those of more complex robots, like six-axis or SCARA models. Industrial robots are required to deliver high levels of accuracy and repeatability and collaborative robots are no exception.

Consider the rotary joints of a collaborative robot as an example. Manufacturers expect the robot to deliver smooth actions, with good rotational accuracy and reliability. However, in robotics applications, there is more to choosing a bearing than simply selecting one that fits.

To guarantee the high levels of rotational precision and reliability required for the operations of a collaborative robot, manufacturers should invest in high quality, precision bearings for the robot’s rotary joints.

Chris Johnson, managing director of bearing distributor SMB Bearings, told PWE that high-quality bearings can prolong the lifespan of industrial equipment. The company is a distributor of Sapporo Precision of Japan, who manufacturer EZO thin section bearings for robotics applications. Johnson says these bearings are lightweight, take up much less space than standard bearings and have excellent standards of roundness and surface finish.

Conversely he added that a poor-quality bearing can result in unexpected downtime caused by inaccurate movement or higher frictional torque creating problems with the robot’s operation. For collaborative robots, any inaccuracies can also create significant health and safety risks for human workers.

Making the most of investments

Naturally, manufacturers investing in collaborative robots are doing so to increase productivity, output and — perhaps most importantly — increase profits in their facility. However, not all manufacturers are aware that incorrect bearings can directly impact the functionality and the longevity of a collaborative robot’s lifespan.

As with any kind of industrial robot, there is no standard bearing that will suit every collaborative robot application. The correct bearing would depend on the environment in which the robot will work and its operations. Manufacturers should speak to a bearing expert for advice on selecting the right bearing specification.

In 2016, collaborative robots represented just three per cent of all industrial robots sold. However, estimates suggest that collaborative robots will account for 34% of all industrial robots sold by 2025. There has never been a better time to invest in collaborative robots.

For further information please visit: www.smbbearings.com

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