Because of the ups and downs of the measurement surface profile, the stylus will move up and down in the direction perpendicular to the measurement profile surface, and move through the electronic transmission device. Then output data and graphs related to roughness through zero specification or other output devices. The surface roughness profiler based on the needle drawing principle is one of the main components of the sensor, driver, pointer, recorder and inductive sensor profiler.
The diamond stylus rests on one end of the sensor rod, and the tip radius of the stylus is applied. During the measurement process, the stylus pen is placed on the workpiece and it is in vertical contact with the surface to be measured. The sensor is used to drag the sensor at a certain speed. Because of the ups and downs of the measured surface profile, when the contact surface slides, the contact will slide up and down.
This kind of movement makes the magnetic core move up and down synchronously through the fulcrum, and subsequently changes the inductance of the two differential inductors around the magnetic core. The coil and the measuring line sensor are directly connected to the balance bridge. The change of the coil inductance causes the bridge to lose balance, so it outputs a signal proportional to the displacement of the upper and lower ends of the contact pin, and this weak power is output through the electronic device. After amplifying the change and performing the phase sensitivity test, a signal indicating the magnitude and direction of the stylus displacement is obtained.
The signal of the roughness profiler is divided into two ways: the first is to add to the zero meter to indicate the position of the stylus, the other is to send to the DC power amplifier, and the recorder is driven to record after being amplified; One is filtered, the average instrumentation amplifier is amplified, and then input into the integral calculator to directly calculate the surface roughness Ra value from the indicator table by performing integral calculation. When the iron core is in the middle position of the homodyne inductance coil, the zero pointer indicates the zero position, which is guaranteed to be within the linear range of the inductance change. Therefore, before the measurement, the zero meter must be adjusted to zero.