Research Of On-line Measurement Of Surface Roughness During Cylindrical Grinding Process

With the development of science and technology, the requirement for fine tolerances and roughness of components is constantly improved. Cylindrical grinding as a final procedure in the productions of precision metal process , used by many fields, it has occupied an important place in efficient and high tolerances field.Decreasing the parts' surface roughness, as it is shown after a long time practice that can realize the reliability and stabilization of the match; can reduce faction coefficient, wear, stress concentration, vibration, noises, and power consumption; can improve the operative precision and perceptivity; can increase the support area and contact intensity; and also can improve wear degree etc. The surface roughness affects capability and longevity of machine and apparatus directly. When we ensure the parts' dimension, shape and position precision, we should not neglect the parts' surface roughness.The measurement of surface roughness has two methods: the contact and the non-contact. The contact measurement uses a special needle moving along the parts' surface with a certain speed. The minute wave of the surface causes the needle to move up and down. After mechanical, optical and electrical conversion, and then amplified, operation, the variation of the needle can show the value of the surface roughness parameter by some instruments or the minute wave profile can be described by some record instruments. However, the contact measurement has many disadvantages: because of the restraint of needle's radius and the measurement speed, it can not be used for measuring the surface roughness value R<0.012. Furthermore, because the needle is crumbly, it is not fit for measuring the surface roughness value R>5.0. Finally, it is impossible for the contact measurement to measure a surface without any derogation. In short, the contact measurement is not fit for measuring soft material or parts' surface roughness processed by a precision metal process.In the non-contact measurement method of the surface roughness, optical measures are major. Because they have high precision and are fit for measuring soft materials, the easily scathed parts and some surfaces with some useful information. The non-contact measurement can compensate the contact measurement's disadvantages very well.In order to increase measurement efficiency of the parts surface roughness during cylindrical lengthways grinding process, an on-line optical measurement method can be adopted. On-line measurement is a kind of on-time measurements. And it can realize constantly measurement during the else time of the processing courses.The on-line measurement of the surface roughness can not only monitor the changes of the state parameters during the processing courses correctly but also can be important for controlling and improving process methods, the qualities of processing surface and the capabilities of the products.Exploiting laser spectrum comparing method, a surface roughness measurement is carried out. When a beam of laser is poured on a rough surface, it will produce a kind of specific particulate appearance. This is called scattered laser spots. According to the optical laws, it will produce scattered and reflection phenomena. The surface's roughness altitude parameter is smaller, the center illumination spots of reflection are more intensive, the scattered radiation belt becomes weaker, shorter and narrower. The surface is rougher, the center illumination spots of reflection are weaker and the scattered radiation belt becomes stronger. In the direction of the reflection, we use a CCD camera to receive the beam. The received reflection beam is focused on a CCD chip by a lens. According to the intensity, the CCD concentrates corresponding charges. It can produce a map of electrical signals after it releases charges periodically. The signals can be changed into standard multiple vision signals after they are filtered and amplified. The vision signals can output the degree of roughness after they are approached...