This setup for magnetisation and magnet bonding in electric motors includes a setup that utilises a four-axis Scara and a six-axis articulated robot arm and offers a wide range of motor sizes and topologies.
Typically, in permanent magnet electric motors, insertion and attachment of non-magnetised magnet blanks within steel laminate rotors are conducted first whilst the magnetisation of these takes place post-assembly. Researchers at WCE wanted to rearrange this process to magnetise first and then place the components in the rotor in a bid to deliver more reliable motors with less potential for any defects.
The research team contacted Horizon Instruments, an automation system integrator and member Mitsubishi Electric’s System Integrator Programme, to create a system that would address this requirement.
The first aspect to address when designing a suitable solution was offering the level of accuracy and flexibility required by the system. In effect, after being magnetised, magnets tend to be very brittle, making their correct insertion within steel laminate particularly challenging. Therefore, the suitable system should offer extreme position accuracy and repeatability, typically provided by computer numerical control machines. Simultaneously, it was important to create a flexible setup that could accommodate multiple motor topologies and sizes, which could only be achieved by using robots.
To overcome this challenge, Horizon Instrument selected two solutions from Mitsubishi Electric.
Melanie Bright, marketing manager – strategic partners at Mitsubishi Electric, said: “Our four-axis RH-6CH and six-axis RV-2FR robots could meet the requirements, as their repeatability is in the order of ± 0.02 mm, amongst the best in the industry. By using these, the WCE could combine the capabilities of a CNC unit with those of our robots.”
The resulting design would see the system use the four-axis robot to collect magnet blanks from a pre-loaded tray and transfer them to a magnetising coil. The six-axis robot, equipped with an adhesive dispensing head mounted on the wrist joint, applies adhesive to the required slots in the rotor. The four-axis robot then collects the magnetised magnets and places them in the prepared slots. Once all the rotor positions are filled with magnets, the machine’s doors unlock and the operator can remove the tray and assembled rotor as well as load new components.
After the two robots were specified, Mitsubishi Electric ensured availability and technical support were provided, including for the unit’s safety system – the MELSEC-WS Series controller. In this way, the team could streamline the completion of the project. In effect, the machine is now fully operational, and ready for the official opening of the WCE in 2023.
The WMG research institution at the University of Warwick is establishing WCE to help UK manufacturers and supply chain companies deliver sustainable electric motors and address electrification needs. The facility received a share of £33m funding from UK Research and Innovation’s Driving the Electric Revolution Challenge, whose selected centres have been designed to support the UK in providing power electronics, machines, and drives. The WMG Centre High Value Manufacturing Catapult at the University of Warwick also contributed £300,000 in funding.
The centre will be open to external partners and is expected to support a range of industry-oriented projects. To succeed, it will feature winding equipment as well as supporting infrastructures, such as impregnation and machine testing units.