JPS62140002A - Method and apparatus for measuring surface roughness - Google Patents

Abstract

PURPOSE:To make possible to measure surface roughness with good accuracy even if the hardness of a surface to be measured is non-uniform, by adjusting pressing force so that the penetration depth of a tracer into the surface to be measured comes to a predetermined value to apply the same to the tracer. CONSTITUTION:When a tracer 4 falls to have a tracer element 5 thereof made a contact with a surface to be measured, the detected load of a load cell 8 becomes large and an operational control apparatus 24 brings the displacement quantity of the probe 4 to zero and outputs a signal which increases the electromagnetic force to a DC power source apparatus 23. Then, the tracer element 5 is penetrated into the surface 1 to be measured while increases the depth and a measuring target band 10 falls relative to a differential transformer 13 and the falling quantity thereof is detected by the apparatus 24 as the displacement quantity detected by the transformer 13. The apparatus 24 keeps the output signal from the apparatus 23 constant at the point in time when said displacement quantity reached predetermined one, and again brings a displacement quantity signal to zero. By this method, the tracer 4 is fed laterally in such a state that the leading and of the tracer element 5 is penetrated up to a predetermined depth. When the lateral feed quantity reaches a predetermined quantity, the tracer 4 is drawn up to be moved to the next measuring start point and measurement in the next measuring range is similarly performed and this operation is repeated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention allows a stylus to be moved relative to the surface to be measured while being pressed against the surface to be measured, and based on the amount of displacement of the stylus in the pressing direction. The present invention relates to a method and apparatus for measuring surface roughness, and more particularly to a method and apparatus for accurately measuring the roughness of a surface to be measured whose hardness is not uniform.

[Prior art]

Conventionally, surface roughness is measured by pressing a hard stylus with a sharp tip against the surface to be measured with a constant force, moving the stylus horizontally along the surface to be measured, and measuring the direction in which the stylus is pressed during horizontal movement. (Japanese Patent Application Laid-Open No. 58-28602).

[Problem that the invention seeks to solve]

However, in the above measurement method, a pressing force is applied to the stylus, so the tip of the stylus penetrates the surface to be measured. The penetration depth is shallow in places with high hardness, and conversely, it becomes deep in places with low hardness, and the roughness of the surface to be measured can be accurately measured using the error factor in the amount of displacement caused by this change in penetration depth. Could not be measured.

[Means for solving problems]

The present invention has been made in view of the above-mentioned problems, and the pressing force is adjusted and applied to the stylus so that the penetration depth of the stylus into the fixed surface to be covered becomes a predetermined value, and the pressing force is applied to the stylus. A method and device capable of accurately measuring surface roughness not only when the hardness of the surface to be measured is uniform, but also when the hardness is non-uniform, by moving a stylus horizontally relative to the surface to be measured while maintaining pressure. The purpose is to provide

The surface roughness measurement method according to the present invention involves moving a stylus in a direction along the surface to be measured relative to the surface to be measured while pressing the stylus against the surface to be measured, and the amount of displacement of the stylus in a direction perpendicular to the surface to be measured. In the method of measuring surface roughness based on The stylus is characterized in that a pressing force is maintained at which the penetration depth into the surface to be measured becomes a predetermined value, and the stylus is moved relative to the surface to be measured while maintaining the pressing force.

[Effect]

The present invention adjusts the pressing force so that the penetration depth of the tip of the stylus into the surface to be measured is constant, so even if there are places with different hardness on the surface to be measured, the influence of hardness on the penetration depth is eliminated. This allows surface roughness to be measured with small errors.

This example] The present invention will be specifically explained below based on the drawings.

FIG. 1 is a schematic diagram showing how the method of the present invention is carried out by the surface roughness measuring device according to the present invention, and in the figure, 1 indicates the surface to be measured on the upper surface of the object to be measured. There is surface roughness on the surface to be measured 1 [
A constant sensor 2 is supported by a support device (not shown) so as to be able to be moved horizontally, and the measurement sensor 2 is placed in a cylinder 3 with an indentation having an axis in the vertical direction, with the lower end opening approximately at the bottom. The protruding cylindrical stylus 4 is provided concentrically. A cylindrical stylus 5 with a sharp lower side is attached to the lower end surface of the stylus 4, and the stylus 5 is usually made of hard diamond.

The inner surface of the cylinder 3 has four levels of different diameters, and from the bottom,
A lowermost inner surface 3a, an intermediate lower inner surface 3b having a diameter smaller than that of the lowermost inner surface 3a, an upper intermediate inner surface 3c having a smaller diameter than the intermediate lower inner surface 3b, and an uppermost inner surface 3d having a larger diameter than the intermediate upper inner surface 3c. The upper end of the stylus 4 is configured to move in a vertical range including the boundary between the intermediate lower inner surface 3b and the intermediate upper inner surface 3c.

A ring-shaped permanent magnet 7 whose inner diameter and outer diameter are the same is concentrically fixed on the inner surface 3a of the lowermost stage, and the permanent magnet 7 has a top opening ij! in the radial middle part thereof. 7a has been opened.

A thin ring-shaped coil attachment member 4a is fixed concentrically to approximately the center of the stylus 4 in the vertical direction, and a coil attachment member 4a has a coil attachment member 4a that has the same outer diameter as that of the lower outer edge of the coil attachment member 4a.
The coil 6 whose wall thickness is smaller than the width of the groove 7a is connected to the groove 78.
It is attached concentrically with the stylus 4 so as not to come into contact with the stylus 4. The depth of the groove 7a and the length of the coil 6 in the axial direction are determined to be values that are sufficiently larger than the level difference when the unevenness level difference of the surface to be measured 1 is maximum.

The coil 6 is supplied with DC current from the DC power supply 23 for controlling the penetration depth, and the electromagnetic force generated between the coil 6 and the permanent magnet 7 by the DC current applies a downward pressing force to the stylus 4. is applied to the stylus 4 to bring it close to the surface to be measured 1, and applying increasing pressure to the stylus 5,
The tip of the stylus 5 is introduced into the surface 1 to be measured.

A bearing 11 with a bearing 12 movable in the axial direction of the stylus 4 is fitted and fixed concentrically on the intermediate lower inner surface 3b, and this bearing 11 is attached to the upper part of the stylus 4 in the radial direction. Prevents sideways swing.

A load cell 8 is attached to the upper end surface of the stylus 4, and the load cell 8 outputs a detected load signal to the arithmetic and control device 24. A displacement measuring rod 9 for detecting the vertical displacement of the stylus is fixed concentrically with the stylus 4 on top of the load cell 8. Measurement target bands 10 having different magnitudes of magnetic susceptibility are wound around.

A cylindrical differential transformer I3 having the same outer diameter as the inner diameter of the intermediate upper inner surface 3c is fixed concentrically with the stylus 4 with a displacement measuring rod 9 inserted therein. The coil is wound in two stages, upper and lower, and the terminal of the coil is connected to the input terminal of the displacement detector 21.

The displacement detector 21 detects the stylus 4 based on the potential difference generated in the differential transformer 13 based on the positional relationship with the measurement target band 10.
The amount of vertical displacement of is detected, and a detection signal is provided to the tJ calculation control device 24.

A disk-shaped permanent magnet 14 with a larger diameter than that is fixed concentrically on the upper end surface of the displacement measurement rod 9, and on the lower surface of the canopy 3e of the cylinder 3 facing the permanent magnet 14. Coils I5 to which DC current is supplied from the stylus-pulling DC power supply device 20 are installed with the axial direction being the top and bottom. The number of turns in the winding direction of the coil 15 and the DC current value supplied from the DC power supply 20 are determined by the stylus 4, the stylus 5° that moves integrally therewith, and the load meter 8. Displacement measurement rod9. The total weight of the measurement target zone 10 and the permanent magnet 14 is determined so as to be able to be sufficiently pulled upward.

The arithmetic and control unit 24 outputs signals related to the power supply level to the stylus pulling DC power supply device 20 and the penetration depth control DC power supply device 23, respectively, and inputs a signal related to the displacement amount from the displacement amount detector 21. Further, the arithmetic and control device 24 receives a signal regarding the lateral feed amount from a lateral feed amount measuring device 26 attached to the support device, and outputs a signal to the lateral feed amount control device 25 based on the signal to measure a predetermined distance. The sensor 2 is moved horizontally, and the recorder 27 records the relationship between the amount of displacement and the amount of horizontal movement.

A method for measuring surface roughness using the apparatus of the present invention configured as described above will be explained.

The arithmetic and control device 24 receives the amount of traverse feed from the traverse feed meter 26, and outputs a stop signal to the traverse feed controller 25 when the amount of traverse feed reaches a preset reference amount of traverse feed. In addition, the power supply level signal in which the pulling force generated between the coil 15 and the permanent magnet 14 was equal to or greater than the total amount W was outputted to the DC power supply 20 until then was changed to a power supply level signal in which the pulling force matches the total weight. A power supply level signal that causes the stylus 5 to press the surface to be measured 1 with a predetermined force is output to the DC power supply device 23. As a result, the stylus 4 slowly descends downward, and the amount of displacement is equal to the differential transformer 13.
It is provided to the arithmetic and control unit 24 via the displacement amount detector 21.

When the stylus 5 comes into contact with the surface to be measured 1, the load detected by the load meter 8 increases, and when this detected load signal is input, the arithmetic and control unit 24 resets the previous displacement amount to zero,
It also outputs a signal to the DC power supply device 23 to gradually increase the electromagnetic force. As a result, the tip of the stylus 5 penetrates while gradually increasing the depth, and the measurement target band 10 descends with respect to the differential transformer 13, and the amount of descent is determined by the arithmetic and control unit 24.
This is detected as the amount of displacement detected by the differential transformer 13 after zero reset.

When the displacement amount reaches a predetermined displacement amount set in advance, the arithmetic control device 24 maintains the output current signal from the DC power supply device 23 constant, and the traverse feed control device 2
A lateral feed command signal is output to 5, and the displacement signal is reset to zero again. As a result, the tip of the stylus 5 is moved laterally in a state in which it has penetrated to a predetermined depth. In other words, the stylus 5 is maintained at a constant pressing force and marks the surface 1 to be measured with a line of a certain depth, and the vertical displacement of the stylus 4 during lateral movement is determined by the differential transformer 13. The horizontal feed amount is detected by the horizontal feed amount measuring device 26. and operation; F, I
The I control device 24 records the displacement in relation to the lateral feed area.
7 to record. When the lateral feed amount reaches a predetermined amount, a predetermined power supply level signal is output to the DC power supply device 20 in order to apply a pulling force capable of pulling up the stylus 4 between the coil 15 and the permanent magnet 14, and the measurement sensor 2 and move it to the next measurement start point.

Then, the next measurement range is measured in the same manner as before, and this process is repeated.

Therefore, according to the present invention, the surface roughness of a smooth surface to be measured showing the change in hardness (H) shown in FIG.
X2. X2~x3+ X3~x4. X4 to x5 are set as shown in Figure 2 (1) so that the penetration depth yo (zero or positive value) of the stylus at the first measurement position of each section is constant as shown in Figure 2 (C1). ), each section is applied with a constant pressing force r, , f2 . f3. When measured at f, Fig. 2 f
As shown in cl, even if the penetration depth of the stylus 5 changes from yo to Va↓Δy in a certain section due to changes in hardness, the measurement will start from the state of constant f and depth y in other sections. Similar measurements are possible. Therefore, when measuring the entire surface to be measured with a constant pressing force as shown in Fig. 3 (1al), the displacement error due to the hardness shown in Fig. 3 (bl) can be reduced as shown in Fig. 2 (C1). did it.

Note that in the above explanation, the stylus is moved horizontally by a predetermined distance in multiple steps, but the present invention is not limited to this when the hardness is constant; Of course, this can also be carried out by measuring the surface roughness.

〔effect〕

As described in detail above, (the present invention has excellent results in that it can accurately measure not only the surface roughness of a surface to be measured whose hardness is uniform, but also that of a surface to be measured whose hardness is non-uniform). .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the implementation state of the present invention, FIG. 2 is a diagram illustrating the effects of the present invention, and FIG. 3 is a diagram illustrating problems in the prior art. 1... Surface to be measured 4... Stylus 5... Stylus 6... Coil 7... Permanent magnet IO... Measurement target band 13... Differential transformer 21... Displacement amount Detector 24...iA Control device patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono 11 fixed number!

Claims (1)

[Claims] 1. While pressing the stylus against the surface to be measured, move it relative to the surface to be measured, and measure the surface based on the amount of displacement of the stylus in the direction perpendicular to the surface to be measured. In the method of measuring roughness, a stylus is approached from a direction perpendicular to the surface to be measured, and after the tip of the stylus touches the surface to be measured, the stylus is pressed and the tip of the stylus is pressed against the surface to be measured. A surface roughness measuring method characterized by maintaining a pressing force such that the penetration depth into the interior of the surface is a predetermined value, and moving a stylus relative to the surface to be measured while maintaining the pressing force. 2. The surface roughness measuring method according to claim 1, wherein one surface to be measured is measured in multiple steps. 3. A device that measures surface roughness based on the amount of displacement of the stylus in the direction orthogonal to the surface to be measured, by moving the stylus relative to the surface to be measured while pressing it against the surface to be measured. , a means for approaching the stylus toward the surface to be measured; a load meter for detecting that the stylus has contacted the surface to be measured; and a means for applying an increasing pressing force to the stylus using electromagnetic force. a displacement amount detector that detects the amount by which the stylus tip penetrates into the surface to be measured and the stylus is displaced by applying the pressing force; and an output signal from the displacement amount detector. and a control device that causes the pressing force applying device to stop increasing the pressing force based on the above, and the displacement amount detector detects the amount of displacement of the stylus when the stylus is moved relative to the surface to be measured. A surface roughness measuring device characterized in that it is configured as follows.