Why is it so important to measure the balancing speed of the workpiece in the balancing machine?

Accurately measuring the rotational speed of a workpiece in a balancing machine is a critical factor in ensuring the reliability of the results. Unbalance measurement relies on the relationship between the centrifugal force created by the mass distribution of the part and the angular position (phase angle) of this force. To perform this measurement accurately, the system must know the exact speed at which the part is rotating and generate a reference signal based on this speed. If the speed measurement is inaccurate, the location and magnitude of the unbalance will also be miscalculated, which can render the correction ineffective or even worsen the situation.

Especially in environments with abundant interference signals, such as factories, the inherent rotational motion of drive elements such as motors and belts increases the need for an accurate speed reference. Modern balancing machines operate by isolating these external factors and using sensitive sensors to accurately determine the instantaneous speed and phase angle of the part. This minimizes phase shifts and inaccurate measurements experienced in older systems. Ultimately, accurate speed measurement isn't just a technical detail; it's a fundamental requirement for ensuring the balancing process is completed accurately, quickly, and reliably. At MBS Balance, we utilize advanced sensors and software in our machines to ensure this critical measurement is always performed with the highest accuracy.

The primary function of speed measurement is to lock the raw vibration signal to the rotor's rotation, extracting only the component synchronous with the speed (1xrpm). Thanks to the reference pulse from the tachometer or encoder, the system applies synchronous filtering (order tracking) and rejects non-synchronous vibrations originating from bearings, belts, or structure. Thus the value shown on the screen is only the vector belonging to the unbalance.

Phase accuracy is directly the accuracy of the correction angle: a shift of a few degrees in the reference signal leads to the weight being placed at the wrong angle and to an increase in residual unbalance. A high-resolution encoder and stable speed reduce this error to a minimum. In MBS Balance machines, precise phase reference and digital synchronous filtering ensure that a consistent amount and angle are read at every revolution, making it possible to achieve a high unbalance reduction ratio in a single correction.