SU1663411A2 - Method of testing soft material surface roughness - Google Patents

Abstract

This invention relates to a measurement technique. In order to increase the accuracy by taking into account the effect on the measurement results of the movement speed of the contact sensor in areas close to the initial, additional measurements of the initial values of the roughness parameter are performed at different speeds of movement of the contact sensor. With the reverse movement of the sensor ensure the absence of contact with a controlled surface. Based on the measurement results, the initial value of the roughness parameter under study is plotted against the velocity and, by extrapolating it to the zero velocity of the sensor, the actual value of the roughness parameter being studied is obtained. 2 Il.

Description

The invention relates to a measurement technique and is an improvement of the method for measuring the surface roughness of soft materials according to the authors. St. Mg 1231399.

The purpose of the invention is to improve the accuracy by taking into account the effect on the measurement results of the movement speed of the contact sensor.

FIG. Figure 1 shows the characteristic dependences of 1, 2, and 3 values of the measured roughness parameter Ra on the number n of measurements, constructed for different velocities V of the movement of the contact sensor Vi, V2 vi Uz at a constant contact force; in fig. Figure 2 shows the dependence of the initial value of the parameter under study on the speed of movement of the contact sensor, constructed according to FIG. one.

The method is carried out as follows.

A tip of the contact sensor is installed on the surface under study and is moved along this surface at least one more time with a given initial speed (Vi) along the same trajectory with a constant contact force. In this case, the reverse movement of the sensor is carried out in the absence of its contact with the surface. According to the measurement results, the dependence of the measured roughness parameter Ra on the number n of measurements (for example, curve 1 in Fig. 1) is plotted and, by extrapolating it to the zero measurement, we obtain the initial value of the parameter

 surface roughness. Then, on the areas close to the initial part of the studied surface, on which equal measurement conditions are guaranteed.

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at least two more similar measurements are made at other sensor movement speeds (V2 and Ou) and additional initial values are determined

the studied parameter is VY and R. According to the obtained data, the dependence of the initial value of the roughness parameter on the speed of movement of the contact sensor (Fig. 2) is plotted and, by extrapolating it to zero velocity, the actual value is obtained

the studied parameter R roughness. The constant force F with which the sensor contacts the surface to be examined is determined by the formula F aS, where S is the cross-sectional area of the needle point of the profilometer stylus; a - the stresses chosen for each material from the interval of 0.01 to 0.16, where cry is the limit of elasticity.

The method makes it possible to significantly improve the measurement accuracy of the roughness parameter by taking into account the grid and eliminating the influence of inertial forces due to the difference in the direction of movement of the sensor and its velocity vector. This difference leads to an acceleration of the sensor tip and a different effect of the tip on the test surface. When a single microroughness is measured around a profile, the inertial forces additionally deform the profile, and subtract from the measuring force on the descending surface of the profile, reduce this deformation.

PRI me R. FIG. Figures 1 and 2 show the results of studies of a copper sample after planing. As a contact sensor, a Model 252 Profilograf profilometer of the Caliber plant was used with a special device that allowed us to vary the speed

sensor movement (recommended by the manufacturer's instructions, the movement speed is 60 mm / min). Measurements were carried out perpendicular to the direction of microscopic irregularities in three areas of the test surface, 0.2 mm apart from each other, at the speeds of movement of the sensor, 6 mm / min; , 0 mm / min; , 0 mm / min.

The results of determining the initial and

The actual values of the roughness parameter shown in FIG. 1 and 2 show that the actual value of the roughness parameter exceeds the initial value by 17.5%.

Claims (1)

The invention The method of controlling the surface roughness of soft materials according to ed. St. NS 1231399, characterized in that, In order to increase accuracy and reliability by taking into account the influence on the measurement results of the movement speed of the contact sensor, at least two more similar measurements are made on adjacent areas of the test surface at other values of the sensor movement speed, reverse the sensor movement in the absence of its contact with this surface, build the dependence of the initial value of the roughness parameter being studied on the sensor movement speed and by extrapolating it to a zero movement speed, get the actual value of the test parameter roughness. Rttthttfi ABOUT n Yaa.mkm 11.0 10.0