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Warner Electric XS & WR Series brakes reduce footprint of six-axis robot

07th January 2021
Six-axis robots have become the standard solution for automated assembly tasks due to their ability to carry out complex manoeuvres. As they have grown in popularity, robot OEMs have strived to reduce the size and mass of their six-axis designs to promote space efficiency and productivity. When a German manufacturer of stepper motors was approached by a robot OEM to downsize its assemblies for a six-axis robot, they turned to Warner Electric to deliver highly compact X-Small (XS) and WR Series brakes.

Able to approach a work piece from any angle, six-axis robots are now a common sight on manufacturing lines. However, floorspace is still at a premium, so there is a continuing design trend towards decreasing the size and mass of robots. Reducing size improves space efficiency, allowing for the addition of more robots or other equipment on the line. Minimising mass allows for six-axis robots to enhance speed and acceleration without compromising payload – which results in increased productivity.

The end goal is a production line with a high density of robots, working within reduced space, delivering high output. Therefore, any advantage that can be gained from reducing the size and mass of components and assemblies must be seized by robot OEMs.

Specifying an optimal robot brake

This has been exemplified by a robot OEM, which asked its German supplier of stepper motors to assess downsizing opportunities for an updated six-axis robot design optimised for small component assembly. The German manufacturer quickly identified the brakes mounted on the back of each stepper motor as an area for optimisation. The brakes provide static holding in precise positions, ensuring the accuracy of the assembly process. Particularly, the stepper motor controlling the sixth axis of movement, which holds and turns the tooling at the end of the robot arm, required a specialised braking solution.

The manufacturer contacted Warner Electric, a leading brand of Altra Industrial Motion Corp., due to its exceptional expertise regarding advanced braking technologies. After collaboration with the customer’s engineering team, Warner Electric experts recommended a XS electrically-released, spring-set brake to fit the stepper motor on the sixth axis.

Warner Electric’s range of XS brakes is specifically designed for applications where weight saving and space efficiency are paramount. Each model offers reliable braking to an optimised torque level. Consequently, XS brakes are often specified for applications in aeronautics and robotics. It is a highly versatile range featuring six standard sizes, with Warner Electric able to customise designs to exactly match application requirements.

The XSB33S supplied to the German motor manufacturer offered a torque rating of 35 Ncm and a weight of only 90 g. Its design ensured a significant size and mass advantage compared to the previously utilised brake. A customised adaptor flange was also included to allow for customer-specific mounting.

Delivering tangible improvement

For the higher braking torques required on the other five axes of the robot, Warner Electric supplied highly compact Model WR220 and WR225 spring-applied, electrically-released brakes. These are specifically designed as statically engaged/disengaged holding brakes, ensuring reliable positioning of the robot arm in operation.

With the new brakes now installed, the German motor manufacturer could approach the robot OEM with a highly optimised design that reduced footprint without compromising productivity. This delivered increased space efficiency for end users, improving available floorspace and enhancing production capacity.

Warner Electric provides a global design, development, manufacturing and supply service to its customers – offering standard and bespoke braking solutions tailored to specific application requirements. Experts worldwide work closely with customers’ engineering teams to provide products that deliver tangible operational improvements. This ensures that the special requirements of advanced industries such as robotics can be met with exact solutions.


Image 1: Six-axis robots have become the standard solution for automated assembly tasks due to their ability to carry out complex manoeuvres. (Image Source: AdobeStock bobo1980 / 142370784)

Image 2: Warner Electric’s range of XS brakes is specifically designed for applications where weight saving and space efficiency are paramount.

About Warner Electric

For over 70 years, Warner Electric has grown to become a global leader in electromagnetic clutch & brake solutions. Warner engineers utilise the latest design, materials and manufacturing technologies to develop easy-to-use and install clutches and brakes with longer life and improved accuracy and repeatability. Warner Electric offers the broadest selection of industrial clutches, brakes, controls, web tension systems, sensors and switches available from a single manufacturer.

Reliable Warner Electric components are used in a very wide range of markets including material handling, packaging machinery, food & beverage, elevator & escalator, turf & garden, agriculture and off-highway, forklift, crane and motion control. Applications include conveyors, lift trucks, wrapping machines, servo motors, capping equipment, combines and balers, baggage handling systems, military vehicles, hoist drives and lawn mowers.

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Editorial Contact: Brittany Kennan

Tel: +44 (0)1905 917477



Address: Progress House, Midland Road, Worcester, Worcestershire, WR5 1AQ, United Kingdom

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Warner Electric: David Brooksbank

Tel: 001 815-389-6227



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