Measurement control

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Measurement of an inside diameter with a measuring controller

The measurement control in machine tools , a control system which the engine control in the accurate positioning supports a tool. The measurement control ensures that a defined position (for example the finished size of a workpiece) is maintained within the smallest possible tolerance.

principle

The current dimension of a workpiece is recorded by a measuring probe during machining . The movements of the probe can be recorded so that the machine control can decide how the tool is to be moved (feed speed, direction).

Usually the movement of the probe is measured by means of a piezo element in the measuring head, which generates an electrical voltage. A typical value is e.g. B. 10 millivolts per micrometer. If the pressure on the measuring head changes, the voltage, which is read by the machine control via an analog input, increases or decreases. Here, a is positioning possible with an accuracy of a few micrometers.

Parameters

Typical parameters of a measurement control are:

  • Linearity range: the range in which the change in output voltage is exactly proportional to the position of the probe
  • Repeatability: defines how exactly a previously calibrated position can be reproduced