PROFILE MEASUREMENT OF MACHINED SURFACE WITH A NEW DIFFERENTIAL METHOD

This article presents a new differential method for surface profile measurement called the combined method, This method, which combines the generalized two-point method with the inclination method, is developed to measure profiles that include high-frequency components whose spatial wavelengths are shorter than the distance between the probes. Differential methods, such as the generalized two-point method and the inclination method, have been used to measure profiles under on-machine conditions. The inclination method can determine relative heights rigorously among discrete points whose interval is equal to the probe interval. Even though the correctness of the relative heights is not influenced by high-frequency components in the profile, the method cannot provide information about points not included in the data group. On the other hand, the generalized two-point method can measure relatively smooth surfaces accurately with a sampling period as short as necessary. The proposed combined method features the advantages of both methods and is capable of rigorously expressing the relative heights of sampled points with a period shorter than the probe interval. Experimental results confirming the effectiveness of the combined method are also presented in this article.