JPH08313248A - Apparatus and method for probe-type measurement of surface roughness - Google Patents

Abstract

PURPOSE: To provide a structure in which the value of the average interval Sm between a recessed part and a protruding part on the surface of an object to be measured is measured precisely, in which an adjusting operation is not complicated and whose production costs are not increased. CONSTITUTION: Before an object to be measured is measured, a reference piece of which the value of the average interval Sm between a recessed part and a protruding part on its surface has been known is placed on a measuring stage (Step 1). The surface of the reference piece is scanned by a detector, and the value Sm1 of the actual Sm is measured (Step 5). Then, on the basis of the actual value Sm1 , of a known value Sm2 and of the preset transfer speed v1 of the detector, the actual transfer speed (v) of the detector is computed (Step 6). Then, on the basis of the actual transfer speed (v), a constant time interval T at which the detector performs a detection operation is computed (Step 7). After that, on the basis of the constant time interval T, the measuring operation of the surface roughness of the object to be measured is performed (Step 10).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a stylus-type surface roughness for quantitatively measuring surface roughness such as surface roughness of a metal surface having a mirror finish, such as fine irregularities on the surface of an object to be measured. The measurement device and the measurement method are intended to improve the measurement accuracy.

[0002]

2. Description of the Related Art For example, in order to measure the surface roughness of a mirror-finished metal surface, various kinds of stylus-type surface roughness measuring instruments have been conventionally used. The parameters representing the surface roughness include arithmetic mean roughness (R _a ), maximum height (R _a ).
_y ), ten-point average roughness (R _z ), average spacing of irregularities (S
_m), local peaks of average spacing (S), the load length ratio (t _p)
Is specified in JIS (Japanese Industrial Standard) corresponding to the international standard (B0601-1994). The above-mentioned conventional stylus type surface roughness measuring device measures, among the above-mentioned parameters, parameters such as maximum height and ten-point average roughness, which represent roughness in the vertical direction.

However, with the fact that the parameters representing the roughness across the lateral direction, such as the average interval between the irregularities and the local peaks, are defined in the JIS, recently, the parameters representing the roughness across the lateral direction. A surface roughness measuring instrument capable of measuring is used. Such a stylus-type surface roughness measuring instrument capable of measuring a parameter representing a lateral (horizontal) roughness among the parameters representing a surface roughness is configured as shown in FIG. 2, for example. There is.

That is, this stylus type surface roughness measuring instrument is provided with a measuring stage 2 on which an object to be measured 1 is placed. Above the measuring stage 2, there is provided a stylus 3 which can be brought into contact with the surface of the object to be measured 1, and a detector 4 which detects the contour of the cross section of the object to be measured 1 by scanning the surface. ing. The stylus 3 is made of diamond, and the radius of curvature of its tip is, for example, 2 μm. The detector 4 is composed of, for example, a differential transformer that magnifies and detects the vertical movement of the stylus 3. The detector 4 is capable of detecting at least one of the parameters representing the roughness of the surface of the DUT 1 representing the roughness in the lateral direction such as S _m and S. Of course, it can also be configured to measure a plurality of parameters representing the surface roughness. As the structure of the detector 4, various structures such as a piezoelectric converter and an inductance modulation type converter are conceivable and actually used. Reference numeral 5 denotes a transfer means, which moves the detector 4 in the lateral direction (one horizontal direction, the horizontal direction in FIG. 2) so that the detector 4 can scan the surface. This transfer means 5 makes the transfer speed of the detector 4 variable in a plurality of steps. When one transfer speed is selected, the detector 4 is transferred at the selected one speed (that is, at a constant speed) until the measurement work is completed.

The detector 4 scans the surface of the DUT 1 to give a predetermined reference length L (for example, 0.8 mm).
The detection is performed a predetermined number of times n (for example, 1500 times). Each value of the reference length L and the number of times n is specified by JIS, and is determined according to this specification. In this way, in order to detect the predetermined number of times n for the predetermined length L, the detector 4 causes the surface to have a constant distance d (=
Detect every L / n). For this reason, the controller 7 controls the detector 4 so that the detector 4 performs the detection operation at a constant time interval corresponding to the constant distance interval d. That is, the detector 4 scans the surface at a selected constant velocity v '. Therefore, if the detection work is performed at constant time intervals t, the detector 4 will detect at each distance v'.t. Therefore, if the constant time interval t is selected so that this v ′ · t becomes equal to the distance interval d (v ′ · t = d), a predetermined n times of detection is performed for a predetermined reference length L. You can Such arithmetic processing is performed by the arithmetic means. In the example shown in FIG. 2, such calculating means is provided in the controller 7, but in addition to this, a microcomputer or the like provided separately from the controller 7 may be used. Further, a timer 6 for measuring the constant time interval is provided so that the controller 7 can cause the detector 4 to perform the detection work at the constant time interval.

The detection value detected by the detector 4 is amplified and detected by the amplification / detection means 10 before being sent to the controller 7, and further converted from analog data to digital data by the A / D converter 8. Converted to data. Further, the controller 7 obtains a cross-section curve, a roughness curve, etc. representing the surface roughness of the DUT 1 based on these digitized detection values, and also the average interval S _{m of the} irregularities. Of the parameters representing the surface roughness, etc., the parameter representing the roughness across the lateral direction is calculated. After this, the display,
It is displayed or output by the display / output means 9 such as a printing machine.

[0007]

However, the above-mentioned conventional measuring instrument has the following problems to be solved. That is, in order to improve the measurement accuracy of the stylus type surface roughness measuring device, it is necessary to strictly regulate the above-mentioned constant distance interval. By the way, as described above, in the conventional measuring device, the detector 4 is controlled based on a constant time interval proportional to the constant distance interval instead of the constant distance interval. Therefore, in order to strictly regulate the constant distance interval, it is necessary to strictly regulate the constant time interval. For this purpose, it is conceivable to improve the accuracy of the moving speed or to make the transfer speed finely adjustable. It is also conceivable to incorporate a digital scale in the transfer means 5 and make the fixed distance intervals highly accurate by reading the scale.

However, with the solutions of (1) to (3) described above, it is inevitable that the price of the surface roughness measuring device itself rises and the adjustment work of the transfer means 5 becomes troublesome. That is, in the case of the solution for improving the accuracy of the moving speed, it takes time and labor to manufacture each component member, and thus the manufacturing cost and the price of the stylus type surface roughness measuring device itself increase. Further, in the case of the solution incorporating the digital scale, the increase in manufacturing cost due to the increase in the number of parts is unavoidable. Further, in the case of the solution that allows the transfer speed of the detector 4 to be finely adjusted, the transfer speed adjustment is troublesome and impractical. The stylus type surface roughness measuring instrument and measuring method of the present invention have been made in view of the circumstances as described above in order to improve the measurement accuracy without requiring complicated work and increasing the cost. It is a thing.

[0009]

Of the surface roughness measuring apparatus and the measuring method of the present invention, the invention relating to the measuring apparatus according to claim 1 has a stylus which can be brought into contact with the surface of an object to be measured, A detector for scanning the surface, a transfer means for moving the detector at a constant speed relative to the object to be measured so that the detector can scan the surface, and a predetermined reference for the detector. In order to detect a predetermined number of times per length, a controller that causes the detector to perform a detection operation at constant time intervals corresponding to the number of times of detection, a timer that measures the constant time interval, and the detector. And a calculation means for calculating at least one parameter representing the roughness in the horizontal direction among the parameters representing the roughness of the surface, based on the plurality of detection values detected by.

In particular, the stylus type surface roughness measuring instrument of the present invention is provided with a reference piece whose values of the above parameters are known. Further, the calculating means is an actual value of the parameter obtained by the detector scanning the surface of the reference piece,
A known value of this parameter and the relative speed of the detector relative to the object to be measured, which is set in advance, calculate the actual relative speed, and the function of calculating the constant time interval based on the actual relative speed. It is characterized by having.

The invention relating to the measuring method described in claim 2 has a stylus which is capable of contacting the surface of the object to be measured, and a detector for scanning this surface, and this detector for freely scanning the surface. Therefore, in order to make the detector relatively move with respect to the object to be measured at a constant speed, and correspond to the number of detections so that the detector can detect a predetermined number of times for a predetermined reference length. Based on a plurality of detection values detected by the controller, a controller that causes the detector to perform a detection operation at fixed time intervals, a timer that measures the fixed time interval, and the surface roughness. By a surface roughness measuring device provided with a calculating means for calculating at least one parameter representing the roughness across the horizontal direction of the parameters represented,
The present invention relates to a surface roughness measuring method for detecting the surface roughness of an object to be measured.

In such a measuring method of the present invention, first of all, prior to the measurement of the object to be measured, the surface of the reference piece whose value of the above parameter is known is scanned by the above-mentioned detector to actually measure the above-mentioned parameter. And measure this actual value,
A known value of the parameter and a preset relative velocity of the detector with respect to the object to be measured are used to calculate an actual relative velocity, and then the constant time interval is set based on the value of the actual relative velocity. It is characterized in that the surface roughness of the object to be measured is calculated and calculated based on this constant time interval.

[0013]

The action itself when measuring the surface roughness of the surface of the object to be measured by the measuring method of the present invention using the stylus type surface roughness measuring instrument of the present invention configured as described above is as described above. This is similar to the case of the conventional measuring device. In particular, in the case of the measuring device of the present invention, at least one parameter representing the roughness across the horizontal direction among the parameters representing the surface roughness is provided with a known reference piece. Then, prior to measuring the surface roughness of the object to be measured, the reference piece is scanned to detect the actual value of the above parameter. In this case, the constant time interval in which the detector performs the detection work is obtained in advance by the calculation means from the predetermined reference length, the number of detections per this reference length, and the set transfer speed of the detector. Further, the calculating means obtains the actual transfer speed by using the actual value of the above parameter, the known value of this parameter, and the preset transfer speed of the detector. Then, from this actual transfer speed, a constant time interval corresponding to this actual transfer speed is calculated. After that, the work of measuring the surface roughness of the object to be measured is performed in place of the reference piece. In this measurement, since the above-mentioned fixed time interval corresponds to the actual transfer speed of the detector, the error between the set value of the transfer speed and the measured value based on the deviation from the actual value is very small, Accuracy is improved.

[0014]

EXAMPLES Next, examples of the measuring apparatus of the present invention will be described. Since the basic structure of the stylus type surface roughness measuring instrument of the present invention is the same as that of the conventional measuring apparatus shown in FIG. 2, duplicate description will be omitted for the same parts. For simplification, the characteristic part of the present invention will be mainly described below. The stylus type surface roughness measuring device of the present invention is provided with a reference piece having a known average interval S _m (unit: mm) of surface irregularities.
The average interval S _m between the irregularities is at least one parameter representing the roughness over the horizontal direction (lateral direction) among the parameters representing the surface roughness of the measured object. Further, the controller 7 is configured to include a calculation means. Therefore, the controller 7 relates to the aforementioned S _m, the detector 4 is the actual value S _m1 obtained by scanning the surface of the reference piece, a known value S _{m @ 2,} a detector 4 which is set in advance With the transfer speed v ₁ (mm / s), it has a function of calculating the actual transfer speed v obtained by v = (S _m2 / S _m1 ) · v ₁ (1). Further, the actual transfer speed v and the reference length L
And the number of detections n, T = (L / v) / n (2) is calculated to have a function of calculating a constant time interval T for controlling the detector 4.

When the surface roughness of the object 1 to be measured is measured by the measuring method of the present invention using the stylus type surface roughness measuring instrument of the present invention having the above-described structure, the operation shown in FIG. As shown in. That is, prior to the measurement work of the DUT 1, as a step 1, the reference piece is placed on the upper surface of the measurement stage 2.
Then, in step 2, the controller 7 is input with the reference length L, which is the measurement condition, the number of times of detection n per the reference length L, and the value S _m2 of the S _m of the reference piece surface known in advance. . Further, the transfer speed of the detector 4 is appropriately selected and the transfer speed v ₁ is input. Then, in step 3, the controller 7 calculates the constant time interval T ₁ corresponding to each of the above values from these values. That is, the constant time interval T ₁ is calculated by T ₁ = (L / v ₁ ) / n. This time interval T ₁ is input to the timer 6 and the measurement of the surface of the reference piece is started (step 4).

As described above, the measurement work of this reference piece is as follows.
This is exactly the same as the case where the surface of the DUT 1 is measured by the conventional measuring device. That is, the surface is detected by the detector 4 at each time interval T ₁ measured by the timer 6. Then, a plurality of detection values (analog data) obtained by this detection work are detected by the detection / amplification means 10, amplified, and then converted into digital data by the A / D converter 8 and sent to the controller 7. . Based on this data, S
determining the actual value S _m1 of _m (step 5). Then, if the above S _m1 is obtained, at step 6, this value S _m1
The known value S _m2 and the transfer velocity v ₁ are set to the above (1).
Substituting into the equation, the actual transfer speed v of the detector 4 is obtained (step 6).

When the actual transfer speed v is obtained as described above, the value of this v is stored in the controller 7. The controller 7 also stores the values L, n, and v ₁ that have been input in advance. Among these values, the values of L, n, and the actual transfer speed v are Substituting into equation (2), a constant time interval T corresponding to the actual transfer speed is calculated (step 7). The value of T is stored in the controller 7, and the timer 6 is set to newly measure the time interval T (step 8).

As described above, by detecting the time interval T based on the actual transfer speed v, the detection work by the detector 4 is accurately performed at the predetermined fixed distance interval D. That is,
The product v · T of the transfer speed v and the constant time interval T is
The distance is exactly D. On the other hand, when the measurement work is performed by the conventional method as it is, the detector 4 is
₁ still carry out the detection work. Therefore, the distance interval D ₁ in this case is v · T ₁ . The above T ₁ is calculated based on the transfer speed v ₁ , and since the above transfer speed v ₁ has an error with respect to the actual transfer speed v, the above T 1
₁ also has an error. Therefore, the distance D ₁ has a deviation from the predetermined distance D. The present invention eliminates such a shift by the processing of steps 1 to 8 described above.

As described above, by measuring the reference piece, the time interval T corresponding to the actual transfer speed is obtained, and if this time interval T is set in the timer 6, it is placed on the measuring stage 2. The reference piece described above is removed, and instead, the DUT 1 whose surface roughness is to be measured is placed (step 9). Then, similarly to the conventional method (measurement work of the reference piece), the surface of the DUT 1 is scanned by the detector 4, and the values of various parameters representing the surface roughness of the DUT 1 are obtained ( Step 10).

In the above embodiment, the transfer speed of the detector 4 is determined by measuring the value of the average interval S _m between the irregularities on the surface of the reference piece. It can also be performed by measuring a parameter representing the roughness across the lateral direction, such as the average interval S between local peaks. In this case, the reference piece having a known parameter is adopted. Further, in the above-described embodiment, the detector 4 is movable and the measurement stage 2 is fixed. On the contrary, the measurement stage 2 is fixed.
It is also applicable to a structure in which the detector 4 is movable and the detector 4 is fixed.
Further, the detector 4 may be movable and the measurement stage 2 may be omitted. Further, the present invention is applied to a surface roughness measuring device that detects a parameter representing roughness in the lateral direction by moving the detector relative to the measured object (scanning the surface of the measured object). I can do things.

[0021]

Since the stylus type surface roughness measuring instrument and the measuring method of the present invention are constructed and operate as described above, one of the parameters expressing the surface roughness of the parameters expressing the surface roughness is You can make accurate measurements. Moreover, in the case of the present invention,
It is possible to obtain a highly practical stylus-type surface roughness measuring device and measuring method without causing a complicated adjusting work and an increase in manufacturing cost.

[Brief description of drawings]

FIG. 1 is a flowchart showing the operation of the present invention.

FIG. 2 is a block diagram showing an example of a surface roughness measuring device.

[Explanation of symbols]

 1 object to be measured 2 measuring stage 3 stylus 4 detector 5 transfer means 6 timer 7 controller 8 A / D converter 9 display / output means 10 detection / amplification means

Claims (2)

[Claims] 1. A detector having a stylus capable of coming into contact with the surface of an object to be measured, the detector scanning the surface, and the detector for allowing the detector to scan the surface. In order to allow the detector to detect a predetermined number of times for a predetermined reference length with a transfer means that moves at a constant speed with respect to the detector, the detector performs a detection operation at regular time intervals corresponding to the number of times of detection. Based on a plurality of detection values detected by the controller, a timer that measures the constant time interval, and a plurality of detection values detected by the detector, the roughness across the horizontal direction among the parameters representing the roughness of the surface is determined. In a stylus type surface roughness measuring instrument having a computing means for calculating at least one parameter, the reference value of the parameter is known, and the computing means is provided with Obtained by scanning the surface of the piece The actual value of the above parameter, the known value of this parameter, and the relative speed of the preset detector with respect to the object to be measured, calculate the actual relative speed, and based on this actual relative speed. A stylus-type surface roughness measuring instrument having a function of calculating the above-mentioned constant time interval. 2. A detector which has a stylus capable of coming into contact with the surface of the object to be measured and which scans the surface, and a detector which allows the detector to scan the surface of the object. In order to allow the detector to detect a predetermined number of times for a predetermined reference length with a transfer means that moves at a constant speed with respect to the detector, the detector performs a detection operation at regular time intervals corresponding to the number of times of detection. Based on a plurality of detection values detected by the controller, a timer that measures the constant time interval, and a plurality of detection values detected by the detector, the roughness across the horizontal direction among the parameters representing the roughness of the surface is determined. A stylus-type surface roughness measuring method for detecting the surface roughness of an object to be measured by a stylus-type surface roughness measuring instrument having a calculating means for calculating at least one parameter Prior to measurement, the values of the above parameters have The actual value of the parameter is measured by scanning the surface of the reference piece with the detector, and the actual value, the known value of the parameter, and the preset object to be measured of the detector. By the relative speed, to calculate the actual relative speed, then calculate the constant time interval based on the value of the actual relative speed, based on the constant time interval, the surface roughness of the measured object. A stylus-type surface roughness measuring method characterized by performing measurement work.