Frequently, servo motors are returned where the brakes are worn. This is almost always due to the brake being applied repeatedly while the motor/load is moving. The application of a motor brake in a "dynamic / moving" scenario will result in dramatic wear of the brake mechanism. As stated in catalogs and manuals, the motor brake is to be applied in a "static / stationary" condition only. Having the drive/control verify the motor is at zero speed, prior to releasing and applying the brake, will ensure a long service life. Also, timing is critical. The catalog will list the times required for brakes to release and apply. If you issue a "run command" as soon as the drive enables (which typically releases the brake), you could possibly have the motor overpowering the brake for say 0.3 seconds.
A great analogy is your car's parking brake. Will it help slow you down if applied while you are moving? Yes - It will. Will it hold up being utilized this way? No. You are applying the parking brake in a manner for which it was not designed, if used while the car is in motion. Like a motor brake, it is designed to hold a stationary body at rest.
If you have any questions, please know you can contact Kollmorgen Application Engineers at any time, to ensure that the system will perform as required.