LORD has a full range of spindle balancing systems designed for high-speed spindle, high precision grinder balancing. The response of the system enables balancing corrections to be performed in seconds, and can be used on machines with automatic tooling changes.
The system is comprised of five parts: balancer, rotary transformer, sensors, controller and software. The balancer is mounted permanently onto the spindle; sensors continuously monitor the vibration levels while running. When an increase in vibration is detected above a pre-determined level, the controller can be programmed to make an automatic balance correction or send an advisory message to a plant control system.
Benefits of the Balancing System include:
- Increases spindle speeds resulting in increased thru put of product
- Improves part tolerance variation
- Eliminates vibration caused by run out
- Increases tool life
- Eliminates manual balancing at setup and tool changing
- Increases spindle/bearing life of the machine tool
- Improves part surface finish
The Balancer
The electro-mechanical balancer consists of a balance ring, which mounts directly onto the spindle shaft. Inside the balance ring are two symmetrical counterweighted rotor assemblies which, when directed, move to create a net correction vector that will offset the measured unbalance. The counterweighted rotors are held in place using permanent magnets that are fixed to the rotors. These magnets create a holding torque, which prevents the rotors from slipping during normal operation, ramp-up or coast down. When a balance correction is required, actuator coil power pulses are sent to magnetically step the rotors to the desired position in a few seconds.
Features of the Balancing System include:
- Balances at spindle speeds up to 40,000 RPM
- Balances to levels below G-1.0 at speed prior to grinding or truing
- Balances the entire spindle and tooling assembly in seconds
- Protects spindles by monitoring vibration continuously and shutting down automatically if vibration is excessive
- Rugged construction withstands the harshest environments
The Actuator Coil
The actuator coil typically mounts to the static portion of the spindle housing. With no moving parts, the actuator coil pulses power to the balancer assembly. The counterweighted rotors are thus moved to the desired counter-balance position. The actuator coil contains sensors for monitoring spindle RPM, as well as the angular location of each counterweighted rotor.
The Controller
The controller continuously monitors vibration levels. When a change occurs which exceed a preset level, the controller determines the optimum balance correction required. Depending upon the mode of operation selected the controller will send an advisory message to the operator and the machines PLC (via either PLC I/O or an RS232 serial port) either of which can instruct the balancer to make an automatic balance correction.
The Software
The full-featured graphical user interface software provides the ability to view real-time amplitude and phase information in both numerical and graphical formats. Additionally the software provides th ability to view the balance correction vector, which provides valuable information regarding the available correction capacity.
The ability to remotely access the software via Ethernet and configure the balancer while initiating the balance correction, is a popular feature of this software package.