New available calibration sample plates cannot mark the starting point of contour, only can calibrate the touching needle type measurer's Ra value (0.15 micrometre - 1.5 micrometre). The patent make use of grind technology, machining out separately the measure regions with unidirectional irregular contours on the middle parts of the high precision plane. The cross of the high precision plane with the measure regions are used to mark the starting point of unidirectional irregular contours, the Ra value can attain 0.015 micrometer - 1.5 micrometer. In addition to the calibrating of Ra value for touching reedle type measurer, it can also be used to calibrate and compare the measured parameters and contour figures of all kinds of roughness measurers and measurement methods. |