New robot automatically assembles rotors of permanent magnet synchronous motors
Magnetic Innovations is the expert in the field of permanent magnet synchronous motors. These motors are typically used for Direct drive Torque motor application which consists of a stator assembly and a rotor assembly. For the stator, there are several automated manufacturing solutions on the market that apply the copper windings fully automated onto the stator. But for the rotors, in order to assemble magnets, mostly customer-specific automation solutions are required, as there is no standard equipment available. Or, it is done by hand. In order to improve the quality of our production line, Magnetic Innovations has developed a robot cell. This robot assembles the rotors automatically and checks the end result for its specified magnetic properties.
Improved position accuracy of the rotors
over the course of the past 2 years the robot has been developed in close collaboration with an external automation and robotization specialist. And, the end result is impressive!
The robot makes a lot of manual work unnecessary and helps to improve our product. The Robot cell is equipped with internal component Storage. Here the rotor parts and magnets are stored until they are picked up by the robot, to be assembled into the magnetic rotor.
The storage space is suitable for processing rotors for our frameless PMSM motors of the MI-F Series from size 110mm up to and including 485mm.
Ensuring the quality of permanent magnet motors
Thanks to years of experience with permanent magnet motors, we know how to ensure the quality of these motors. Magnetic Innovations assesses the quality of a magnetic rotor based upon:
- The accuracy of the starting materials used.
- The magnetic field strength across position.
- The adhesive process mount the magnets to the rotor.
First, an input check takes place, which determines whether the starting materials have been supplied in accordance with specifications. In addition, the machine checks each magnet individually, to see if it is within a specified bandwidth in terms of magnetic properties. If not, it is registered and rejected and the next magnet is used.
By implementing this quality check, we are able to obtain a very homogeneous magnetic field in the rotor. Which provides very good properties in terms of low torque constant ripple and cogging.
The permanent magnets are attached to the rotor by means of adhesive bonding. Adhesive bonding has proven itself for many years within the high-tech and aviation industry. It is very reliable, provided the right conditions are used. The choice in terms of adhesive, dosage, and the connection process determine the quality.
The type of adhesive has been chosen based on our experience and expertise in bonding permanent magnets and rotors. The adhesive we have selected has been extensively tested and found to be suitable for all motor and environmental specifications as they apply to our motors.
To achieve good adhesion of the adhesive and thus a good adhesive connection, it is very important to clean the surface and make it suitable for adhesion. This step in the process is also fully automated.
After the magnets are placed in the storage chamber of the robot cell. The robot, by means of atmospheric plasma, cleans and activates the adhesive surface of both, the rotor part and the magnet, so that an optimal adhesive connection can be obtained.
High position accuracy enhances the magnetic field of the pm motors
In order to avoid a build-up of position tolerances, we have devised a unique solution with which we can pick-up and position the magnets. This makes it possible to achieve a high position accuracy, which contributes to a very homogeneous magnetic field in the rotor. Homogeneity of the magnetic field in a rotor provides very good properties in terms of low cogging and low torque constant ripple. And a generally smooth running motor.
After applying all magnets, the entire magnetic field is scanned and specifications are verified to the specification requirement. Based on a unique serial number, a fingerprint of the particular rotor is stored for future reference and traceability.
This new robot takes away the need for manual labor in rotor manufacturing, increases our manufacturing capacity and helps to improve the performance of our product. Magnetic Innovations has taken a major leap forward when it comes to the efficiency and positioning accuracy of our rotors thanks to this new robot.