1. contact roughness measuring instrument: the contact roughness measuring instrument is used to measure the surface of the measured object by contacting the mechanical probe. When the mechanical probe contacts the measured surface, the measuring system will record the movement track and force change of the mechanical probe. By measuring the movement and force change of the probe on the surface, the surface topography parameters can be calculated. The key in the measurement principle is the contact and movement between the probe and the measured surface, so it is necessary to ensure the stability and accuracy of the probe.
Advantages: The equipment cost is relatively low.
Disadvantages: high cost of probe maintenance and replacement; The measurement speed is slow and the accuracy is low; Damage to the measured object; There are requirements for the materials to be measured, and soft materials and sharp products are difficult to measure.
Non-contact roughness measuring instrument: Non-contact roughness measuring instrument generally adopts optical principle. For example, white light interferometer, which uses the principle of optical interference to obtain the surface information of objects, is a precise measuring instrument, which can measure the surface roughness of objects with high precision. The white light interferometer driven by piezoelectric ceramic devices has high measurement accuracy, which can reach sub-nanometer level. The white light interferometer driven by high-precision high-speed piezoelectric ceramic unit with large range has a precision of 0.03nm and a scanning speed of 400 μ m /s, which is widely used in many industries such as new energy, semiconductor, precision machining, precision optics, aerospace, 3C products, materials, liquid crystal and so on.
Advantages: fast measurement speed and high precision; Do not damage the measured object; There is no requirement for materials, and soft materials and sharp products can also be measured.
Disadvantages: the equipment cost is relatively high.
To sum up, the measurement of surface roughness needs to choose the appropriate measurement method according to the actual measurement situation and demand.