JP2021089226A - Tapered face shape and face property inspection device - Google Patents

Abstract

To stably inspect the shape and face properties of a tapered face.SOLUTION: A tapered face shape and face property inspection device 10 comprises: a light source 20; a beam splitter 40 arranged on the optical axis of the light source; a placement table 61 for placing an inspection object 60 having a tapered face and arranged on the transmitted or reflected light path of the beam splitter 40; a comparison object 50 installed on the transmitted or reflected light path of the beam splitter 40 and having a tapered face, the face properties of which satisfy a prescribed standard; an imaging unit 80 facing the inspection object 60 placed on the placement table and the comparison object 50 via the beam splitter 40; and a telecentric lens 70 arranged between the beam splitter 40 and the imaging unit 80.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tapered surface shape and surface property inspection device.

In order to improve the machining accuracy of the machine tool, it is necessary to adjust the fit between the tapered hole of the spindle of the machine tool and the tooling with high accuracy. For example, Patent Document 1 discloses a shape measuring method and a shape measuring device capable of accurately measuring the tapered shape of a work (for example, Patent Document 1).

For example, a hit inspection is performed to inspect whether the tapered hole of the spindle of the machine tool meets a predetermined standard. In the hit inspection, a taper gauge that is finished with high precision according to the standard is used, and the ratio of the inner and outer diameters of the tapered hole and the length of the diameter (taper ratio) and the taper angle (angle between the cross section and the bus) meet the standard. Is inspected. As an inspection result, a "hit rate" indicating how much the tapered surface of the spindle tapered hole touches the tapered surface on the outer circumference of the taper gauge is evaluated. The higher the hit rate, the higher the accuracy of the product.

In the conventional hit inspection, by inserting the taper gauge coated with brew paste into the taper hole, the brew paste applied to the taper gauge is transferred to the tapered surface of the tapered hole, and the brew paste transferred to the tapered surface is visually confirmed. By doing so, the "hit rate" was judged. However, in the hit inspection, "the brew paste must be applied to the taper gauge quickly and uniformly", "the taper gauge must be inserted into the taper hole so as not to contact other parts", and "the taper gauge must be inserted into the taper hole". The work itself related to the inspection was very difficult, such as "It must be rotated while pressing it with a uniform force."

Japanese Unexamined Patent Publication No. 2004-061248

It is desired to be able to stably inspect the shape and surface properties of the tapered surface.

The tapered surface shape and surface property inspection device according to one aspect of the present disclosure includes a light source, a beam splitter arranged on the optical axis of the light source, and a tapered surface arranged on the transmitted light path or the reflected light path of the beam splitter. On the mounting table for mounting the inspection target having the above, and the comparison target having a tapered surface having a surface property satisfying a predetermined standard, which is installed on the reflected light path or the transmitted light path of the beam splitter, and the mounting table. It includes an imaging unit that faces the mounted inspection target and the comparison target via a beam splitter, and a telecentric lens that is arranged between the beam splitter and the imaging unit. The reflected light reflected on the tapered surface to be inspected and the reflected light reflected on the tapered surface to be compared are superposed by the beam splitter, and an interference image corresponding to the phase difference is imaged by the imaging unit.

According to this aspect, the shape and surface properties of the tapered surface can be stably inspected.

FIG. 1 is a perspective view showing the shape of the tapered surface and the appearance of the surface property inspection device according to the present embodiment. FIG. 2 is a perspective view showing the shape of the tapered surface of FIG. 1 and the spindle of the machine tool to be inspected by the surface property inspection device together with tooling. FIG. 3 is a supplementary view for explaining the shape of the tapered surface of FIG. 1 and the inspection principle of the surface property inspection apparatus. FIG. 4 is a diagram showing an example of an interference image output from the tapered surface shape and surface property inspection device of FIG. FIG. 5 is a diagram showing another example of an interference image output from the shape and surface property inspection device of the tapered surface of FIG.

Hereinafter, the tapered surface shape and surface property inspection device (hereinafter, simply referred to as an inspection device) according to the present embodiment will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are designated by the same reference numerals, and duplicate explanations will be given only when necessary.

The inspection device according to the present embodiment is a device for inspecting the surface shape and surface properties of a tapered surface. As shown in FIGS. 1 and 2, here, the inspection target is the spindle 60 of the machine tool having the tapered hole 601 (hereinafter, simply referred to as the inspection target 60). The surface shape (taper ratio or taper angle) and surface texture (surface roughness) of the tapered surface 603 of the tapered hole 601 of the inspection target 60 are defined in a predetermined standard, for example, JIS standard or ISO standard. The comparison target for determining the quality of the tapered surface 603 of the inspection target 60 is the spindle 50 of the machine tool manufactured according to the same specifications as the inspection target 60 in terms of surface shape, surface texture and material (hereinafter, simply referred to as the comparison target 50). ). The tapered surface 503 of the comparison target 50 satisfies a predetermined standard, and is tapered by a precision measuring machine such as a three-dimensional coordinate measuring machine, a roundness measuring machine, a contour shape measuring machine, and a surface roughness meter. It is desirable that the shape and surface texture of the surface are accurately priced. One of the inspection devices according to the present embodiment is to directly compare the tapered surface 603 of the comparison target 50 with the tapered surface 503 of the comparison target 60 satisfying a predetermined standard, and output the comparison result as an image. It is a feature. In the image output from the inspection device, a small dimensional difference between the tapered surface 503 of the comparison target 50 and the tapered surface 603 of the inspection target 60 appears as distortion of the interference fringes. The inspector can determine the quality of the tapered surface 603 of the inspection target 60 by checking the interference fringes.

The inspection target is not limited to the tapered surface of the spindle of the machine tool, and may be, for example, the tapered convex portion 103 of the tooling 100 that is inserted and attached to the tapered hole of the spindle of the machine tool. Of course, as long as it has a tapered surface, it may be a product without a unified standard that defines the surface shape and surface properties. In this case, the comparison target can be a product manufactured according to the same specifications as the inspection target and satisfying standards such as in-house standards and product standards.

(Outline of inspection device 10)
As shown in FIGS. 1 and 3, the inspection device 10 has a light source 20. Typically, as the light source 20, an LED that generates white light or a semiconductor laser that generates laser light can be used. When a semiconductor laser is used as the light source 20, a beam expander that expands the laser may be used instead of the first telecentric lens 30 described later. A mounting table 41 on which the beam splitter 40 is mounted is arranged on the optical axis of the light source 20. The beam splitter 40 splits the incident light into reflected light and transmitted light. The beam splitter 40 is arranged so that the transmitted optical path is parallel to the optical axis of the light source 20 and the reflected optical path is orthogonal to the optical axis of the light source 20. As a result, the light source 20 and the beam splitter 40 form a coaxial epi-illumination.

A first telecentric lens 30 that converts the irradiation light from the light source 20 into parallel light is arranged between the light source 20 and the beam splitter 40. The first telecentric lens 30 is mounted on the mounting table 31. Typically, as the first telecentric lens 30, an object-side telecentric lens having a telecentric structure only on the object side (here, the beam splitter 40 side) can be used. The first telecentric lens 30 may be excluded from the components as long as the interference fringes can be observed in the interference image captured by the imaging unit 80 described later.

The comparison target 50 is arranged on the transmitted light path of the beam splitter 40. The comparison target 50 is placed on the comparison target mounting table 51 so that its tapered surface 503 (opening of the tapered hole 501) faces the beam splitter 40. The inspection target 60 is arranged on the reflected light path of the beam splitter 40. The inspection target 60 is placed on the inspection target mounting table 61 so that its tapered surface 603 (opening of the taper hole 601) faces the beam splitter 40. Typically, a three-axis moving stage can be used as the comparison target mounting table 51 and the inspection target mounting table 61. The inspector can move the comparison target 50 in a direction parallel to the transmitted optical path or the like by operating the comparison target mounting table 51. Similarly, the inspector can move the inspection target 60 in a direction parallel to the reflected optical path or the like by operating the inspection target mounting table 61.

A camera 80 as an imaging unit 80 is arranged on the interference light path of the beam splitter 40 on the opposite side of the inspection target mounting table 61 with the beam splitter 40 in between. The camera 80 is arranged so that its optical axis is parallel to the interference optical path. A second telecentric lens 70 for converging the interference light from the beam splitter 40 on the camera 80 is arranged between the camera 80 and the beam splitter 40. The second telecentric lens 70 is mounted on a mounting table 71 having a mechanism that can move along three orthogonal axes. The second telecentric lens 70 is typically a bilateral telecentric lens having a telecentric structure on both the object side and the image side. The second telecentric lens 70 may be an object-side telecentric lens. Further, each of the mounting tables 31, 41, 51, 61, 71 is a moving stage having a mechanism capable of finely adjusting the position and orientation of the mounted object, and typically can be translated along three orthogonal axes. , A 5-axis moving stage in which the pitch angle and the yaw angle can be adjusted can be used. Of course, one or more of the mounting tables 31, 41, 51, 61, 71 may be other moving mechanisms, for example, a three-axis moving stage capable of translation along three orthogonal axes.

(Inspection method using inspection device 10)
In the inspection device 10, the optical path length from the beam splitter 40 to the predetermined reference plane of the inspection target 60 (optical path length on the inspection target side) and the optical path length from the beam splitter 40 to the predetermined reference plane of the comparison target 50 (comparison target side). The center line of the taper hole 601 of the inspection target 60 and the center line of the taper hole 501 of the comparison target 50 coincide with each other on the interference image output from the camera 80. The comparison target mounting table 51 and the inspection target mounting table 61 are adjusted. The predetermined reference surface is typically the opening surface of the tapered hole 501 of the comparison target 50 and the opening surface of the tapered hole 601 of the inspection target 60. In the above pre-adjustment, for example, two products manufactured according to the same specifications as the inspection target 60 and having a tapered surface satisfying the standard are arranged on the comparison target mounting table 51 and the inspection target mounting table 61, respectively. Then, the interference image from the camera 80 is set to be the interference image shown in FIG.

As shown in FIG. 3, the irradiation light from the light source 20 is converted into parallel light by the first telecentric lens 30 and is applied to the beam splitter 40. A part of the parallel light from the first telecentric lens 30 passes through the beam splitter 40 and is irradiated to the comparison target 50 on the transmitted light path, and a part is reflected by the beam splitter 40 and irradiates the inspection target 60 on the reflected light path. Be done.

The reflected light (reference light) reflected by the tapered surface 503 of the comparison target 50 is again applied to the beam splitter 40, and a part of the reflected light is reflected by the beam splitter 40 and guided to the interference optical path. Similarly, the reflected light (inspection light) reflected by the tapered surface 603 of the inspection target 60 is again applied to the beam splitter 40, and a part of the reflected light is transmitted through the beam splitter 40 and guided to the interference optical path. In this way, the reference light and the inspection light are superposed by the beam splitter 40 and incident on the camera 80 as interference light. The camera 80 receives the interference light from the beam splitter 40 via the second telecentric lens 70, and generates data of an interference image according to the phase difference between the reference light and the inspection light. The interference image is displayed on a display unit (not shown), and the inspector can observe the interference image and judge whether the tapered surface 603 of the inspection target 60 is good or bad.

The distance from the opening surface of the inspection target 60 to the beam splitter 40 and the distance from the opening surface of the comparison target 50 to the beam splitter 40 are equally arranged so that the central axis of the inspection target 60 and the optical axis of the inspection light coincide with each other. When arranged so that the central axis of the comparison target 50 and the optical axis of the reference light coincide with each other, the phase difference between the reference light and the inspection light is determined by the beam splitter 40 to the tapered surface 603 of the inspection target 60. Corresponds to the difference between the distance to the position and the distance to the predetermined position of the tapered surface 503 of the comparison target 50, that is, the difference in the optical path length.

When the comparison target 50 and the inspection target 60 are arranged as described above, the surface shape and surface properties of the taper surface 603 of the inspection target 60 are completely the same as those of the taper surface 503 of the comparison target 50. Since the phase difference between the reference light and the inspection light is zero and they strengthen each other, as shown in FIG. 4, the interference image has the same brightness value of each pixel constituting the interference image and is uniformly bright. Appears as an image. As shown in FIG. 4, when the interference fringes do not appear in the interference image, the inspector may judge that the tapered surface 603 of the inspection target 60 is a high-precision good product having a hit rate of 100%. it can. However, when at least one of the shape and surface texture of the tapered surface 603 of the inspection target 60 does not match the tapered surface 503 of the comparison target 50, interference fringes occur in the interference image.

For example, when the tapered surface 603 of the inspection target 60 is partially rough with respect to the tapered surface 503 of the comparison target 50, interference fringes partially appear in the interference image as shown in FIG. The positions of the portions 505, 506, and 507 where the interference fringes appear on the interference image correspond to the positions where the tapered surface 603 of the inspection target 60 has a dimensional difference from the tapered surface 503 of the comparison target 50. The inspector can determine the ratio of the portion where the interference fringes appear to the entire tapered surface by checking the interference image, and determine the quality of the inspection target 60.

The inspection device 10 according to the present embodiment automatically determines the quality of the inspection target 60 based on the data of the interference image from the camera 80 in case the inspector cannot judge the quality of the inspection target 60 at a glance. A matching degree calculation unit (processing device) 90 for calculating the matching degree of the tapered surface 603 with respect to the tapered surface 503 of the comparison target 50 is provided.

For example, the matching degree calculation unit 90 calculates the ratio of the number of pixels of the portion where the interference fringes appear to the number of pixels forming the tapered surface as the matching degree in the interference image. The degree of coincidence calculated by the degree of coincidence calculation unit 90 is displayed together with the interference image on a display unit (not shown). As shown in FIG. 5, the inspector confirms the degree of matching calculated by the matching degree calculation unit 90 even when the quality of the inspection target 60 cannot be determined by looking at the interference image, and the inspection target 60 is checked. Can be judged as good or bad.

In the interference image, even if the dimensional difference between the tapered surface 503 of the comparison target 50 and the tapered surface 603 of the inspection target 60 appears as interference fringes or shading of the image, the dimensional difference is a shape such as a dimensional tolerance or a geometrical tolerance. In some cases, it meets the standards for surface properties such as surface roughness. The matching degree calculation unit 90 applies a known method such as a phase shift method to calculate the dimensional difference between the tapered surface 503 of the comparison target 50 and the tapered surface 603 of the inspection target 60 at each position from the data of the interference image. Each of the tapered surfaces 603 of the inspection target 60 is based on the calculated dimensional difference of each position of the tapered surface 603 of the inspection target 60 with respect to the tapered surface 503 of the comparison target 50 and the known dimensions of the tapered surface 503 of the comparison target 50. Calculate the dimensions of the position. Then, the coincidence degree calculation unit 90 may calculate the ratio of the tapered portion satisfying a predetermined standard as the coincidence degree with respect to the entire tapered surface.

By using the tapered surface shape and surface property inspection device 10 described above, the inspector can confirm the interference image taken by the camera 80 and judge the quality of the inspection target 60. Further, even if the inspector cannot judge the quality of the inspection target 60 at a glance of the interference image, the inspection target 60 can be judged as good or bad by supplementarily utilizing the degree of matching displayed numerically together with the interference image. Can be judged. If the positions and orientations of the parts constituting the inspection device 10 are adjusted before the inspection, the work substantially performed by the inspector during the inspection is the work of placing the inspection target 60 on the inspection target mounting table 61. Only. In this work, by using a jig or the like for aligning the inspection target 60 with respect to the inspection target mounting table 61, even if the worker is not a skilled worker, the inspection target 60 can be placed with respect to the inspection target mounting table 61. It can be easily fixed in the same position at all times. That is, according to the tapered surface shape and surface property inspection device 10 according to the present embodiment, the inspector can stably inspect the surface shape and surface property of the tapered surface in a short time.

The inspection device 10 can be configured by exchanging the position where the comparison target 50 is installed and the position where the inspection target 60 is installed. Further, if the inspector only needs to be able to confirm the interference image, a screen on which the interference image is projected may be arranged instead of the camera 80. Further, in the present embodiment, the comparison target 50 is a product manufactured according to the same specifications as the inspection target 60, but it may be an inspection-dedicated product having a tapered surface finished for inspection.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

10 ... Tapered surface shape and surface property inspection device, 20 ... Light source, 30, 70 ... Telecentric lens, 31, 41, 51, 61, 71 ... Mounting table, 40 ... Beam splitter, 50 ... Comparison target, 60 ... Inspection target , 80 ... Imaging unit, 90 ... Matching degree calculation unit (processing device).

Claims (7)

Light source and
A beam splitter arranged on the optical axis of the light source,
A mounting table for mounting an inspection target having a tapered surface, which is arranged on the transmitted light path or the reflected light path of the beam splitter, and
A comparison object having a tapered surface whose surface properties satisfy a predetermined standard, which is installed on the reflected light path or the transmitted light path of the beam splitter.
An imaging unit that faces the inspection target and the comparison target placed on the above-mentioned stand via the beam splitter, and an imaging unit.
A telecentric lens arranged between the beam splitter and the imaging unit is provided.
The reflected light reflected on the tapered surface to be inspected and the reflected light reflected on the tapered surface to be compared are superposed by the beam splitter, and an interference image corresponding to the phase difference is imaged by the imaging unit. , Tapered surface shape and surface property inspection device. The shape and surface property inspection device for a tapered surface according to claim 1, wherein another telecentric lens is arranged between the light source and the beam splitter. The shape and surface property inspection device for a tapered surface according to claim 1 or 2, wherein the comparison object and the inspection object are products manufactured according to the same specifications regarding the taper angle or taper ratio, surface properties and materials. .. The shape and surface property inspection apparatus for a tapered surface according to any one of claims 1 to 3, wherein the distance from the beam splitter to the inspection target and the distance from the beam splitter to the comparison target are the same. .. The stand according to any one of claims 1 to 4, further comprising a mechanism for moving the inspection target in a direction parallel to the transmitted light path or the reflected light path in order to adjust the optical path length from the beam splitter to the inspection target. The taper surface shape and surface property inspection device according to item 1. The tapered surface shape and surface property inspection device according to any one of claims 1 to 5, wherein the light source constitutes a coaxial epi-illumination together with the beam splitter. The device for inspecting the shape and surface properties of a tapered surface according to any one of claims 1 to 6, wherein the light source generates white light or laser light.

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