Tech Talk
Why "balance a wheel" and what are the optional methods?
Grinding wheels have inhomogeneous structures. Caused by manufacturing tolerances and mounting errors, center shift is created.
This condition causes uneven centrifugal force during the run of the grinding wheel which we call imbalance.
The imbalance can create an obliged vibrating action on the machine, which creates a larger roughness and chattermarks.
The balancing can be done off or on the machine. The static imbalance is observed by a swing action. The grinding wheel mounted on the wheel adaptor has to be put on an arbor. When the set-up is level and the friction is low, the heavy side takes the lowest point on, when it deviates from the rotating axis.
The balancing counter weights have to be shifted until the grinding wheel is not rotating in any position. Since the grinding wheel gets its final shape on the periphery after dressing the gfirst time, the procedure has to be repeated.
With the fine balancing unit BALANTRON the balancing can be done on the machine. The unit consists of the amplifier with the indicator, and a pick-up and an actuator. Via the pick-up and the amplifier, the imbalance producing material is removed by the actuator.
The Balantron also offers the possibility to static balance on the machine. The impregnated diamond on the actuator is then replaced by a grease pencil. The grease pencil indicates the position of the imbalance. With this method non vitrified wheels can be balanced.
The Balantron can be utilized in an RPM range of 600 to 5500. The unit is not machine dependent and can be moved easily. It is a perfect solution for rebalancing of grinding wheels on several machines.
Basically there are two systems: mechanical weight movement, and liquid compensation. The balancing heads or the balancing chambers can be mounted or integrated into the grinding wheel adaptor, or even onto the grinding spindle.
With the signals of the pick up and the RPM counter, the amplifier determines the phase position and the amount of the imbalance. Via the solenoid battery and the injector unit coolant is injected into the chamber which is assigned by the phase position. This procedure is repeated, until the desired imbalance is reached.
The measuring and regulating control can be interfaced with the machine control. E.g. the machine control orders a balancing. As soon as the preset imbalance has been reached, the balancing system tells the machine that the wheel has been balanced.
The drainage of the balancing chambers is done by the stopping of the grinding spindle. A permanently installed balancing system has the advantage that the wheel can be balanced after every dress. The balancing procedure will take about 5 to 15 seconds, depending on imbalance.
