Work precision measurement method

Abstract

To provide a technique for measuring accuracy of a workpiece without requiring complicated work.SOLUTION: A workpiece accuracy measurement method includes: a first fixation process which arranges shim between an accuracy measurement instrument and a workpiece manufactured by press molding and fixes the workpiece to the accuracy measurement instrument; a first measurement process which measures a distance between a predetermined first measurement point on the workpiece and a first target position after the first fixation process; a second fixation process which replaces, when the distance is equal to or larger than a predetermined threshold, the shim with a viscoplastic body which can be plastically deformed easier than the shim, and fixes the workpiece to the accuracy measurement instrument; a deformation process which deforms the viscoplastic body so that positions of multiple predetermined second measurement points may be closer to a second target point than multiple second measurement points on the workpiece in the first fixation process; and a second measurement process which measures, after the deformation process, using a measurement apparatus, a deviation between arrangement of the workpiece including the distance and arrangement of the workpiece in a target shape.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for measuring work accuracy.

Background Art

[0002] As a method for measuring the accuracy of a work manufactured by press molding, for example, as described in Patent Document 1, a technique is known in which the work is placed on a checking fixture (CF) jig and the distance from the target position in the CF jig to the work is measured.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In measuring the accuracy of a work using a CF jig, in order to adjust the dimensions of the CF jig and the position of the work, a shim plate, which is a plate-like member of resin or metal, may be placed between the CF jig and the work. In this case, there is a possibility that the shim plate needs to be cut and adjusted to a desired thickness and shape. Therefore, a technique that can measure the accuracy of a work without requiring complicated operations has been desired. Also, in the preparation for manufacturing a mold used for press molding, it has been required to suppress the cost of mold repair by minimizing the repair area of the mold.

Means for Solving the Problems

[0005] The present disclosure has been made to solve the above-described problems and can be realized in the following forms.

[0006] (1) According to one embodiment of the present disclosure, a workpiece accuracy measurement method is provided. This workpiece accuracy measurement method includes a first fixing step of disposing a shim between a workpiece manufactured by press molding and an accuracy measurement jig and fixing the workpiece to the accuracy measurement jig, and after the first fixing step, a first measurement point Position and In the workpiece of the target shape the first measurement point Corresponding to a first measurement step of measuring the distance from the first target position which is the position, and when the distance is equal to or greater than a predetermined threshold value, replacing the shim with a viscoplastic body that can be more easily plastically deformed than the shim and fixing the workpiece to the accuracy measurement jig, and the positions of a plurality of predetermined second measurement points on the workpiece are closer to the In the workpiece of the target shape respective Corresponding to second target positions which are the positions of the plurality of second measurement points than the positions of the plurality of second measurement points on the workpiece in the first fixing step, a deformation step of deforming the viscoplastic body so as to approach, and after the deformation step, using a measuring device, a second measurement step of measuring the deviation between the shape of the workpiece including the distance and the target shape State and are included. According to the workpiece accuracy measurement method of this embodiment, since the viscoplastic body is deformed to measure the dimensional accuracy, the work of processing the accuracy measurement jig and the shim can be omitted. Therefore, complicated work can be suppressed. In addition, since the workpiece is brought closer to the target position than when using a shim, in the manufacturing preparation of the mold used for press molding the workpiece, the repair area of the mold can be reduced. Therefore, the cost of mold repair can be suppressed. (2) In the workpiece accuracy measurement method of the above embodiment, before the deformation step, an analysis step of analyzing the shape of the viscoplastic body whose deviation satisfies a predetermined condition may be included, and in the deformation step, the viscoplastic body may be deformed into the shape analyzed in the analysis step. According to the workpiece accuracy measurement method of this embodiment, since the viscoplastic body is deformed into the analyzed shape, it can be deformed into a shape that satisfies the deviation condition. Therefore, the working time can be shortened. (3) In the workpiece accuracy measurement method of the above embodiment, the measuring device may be a device that measures dimensions non - contact. By using a non-contact device, it is possible to suppress the deformation of the viscoplastic body when measuring dimensions.

[0007] Note that the present disclosure can be realized in various forms. For example, it can be realized in the form of a workpiece accuracy measurement method for modifying a mold used in press molding.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] A. First Embodiment: FIG. 1 is a flowchart showing an example of a workpiece accuracy measurement method in the present embodiment. FIGS. 2 to 4 are explanatory diagrams of each step in the workpiece accuracy measurement method. In the present embodiment, the shape accuracy of the workpiece Wk is measured for modifying the mold used in press molding. For example, the accuracy measurement process shown in FIG. 1 is performed using the workpiece Wk before mold repair before the operation of the manufacturing line of the workpiece Wk. Note that the shape accuracy of the entire workpiece Wk may be measured, or the shape accuracy of a part of the workpiece Wk may be measured.

[0010] First, in step S100 (see FIG. 1), a shim SP is placed between the workpiece Wk manufactured by press molding and the precision measurement jig CF, and the workpiece Wk is fixed to the precision measurement jig CF. This step is also referred to as the "first fixing step". As shown in FIG. 2, an operator fixes the workpiece Wk to the precision measurement jig CF via the shim SP. In the present embodiment, the workpiece Wk is fixed to the precision measurement jig CF using a clamp CP. The shim SP is a material that plastically deforms irreversibly by an external force. In the present embodiment, the shim SP is a plate-shaped resin member.

[0011] In FIG. 2, the shape indicated by the dashed line is the desired shape of the workpiece Wk that was originally intended to be manufactured by press molding in the present embodiment. Also, the position of the shape indicated by the dashed line in FIG. 2 shows the position of the workpiece Wk when the workpiece Wk of the desired shape is fixed to the precision measurement jig CF via the shim SP. Hereinafter, the position of the workpiece Wk of the desired shape indicated by the dashed line in FIG. 2 is also referred to as the desired arrangement Tp.

[0012] In step S110 (see FIG. 1), the distance Ln between the position of the first measurement location Pw predetermined in the workpiece Wk and the target position of the first measurement location Pw, that is, the first target position Pt which is the position of the first measurement location Pw in the desired arrangement Tp, is measured. This step is also referred to as the "first measurement step".

[0013] In step S120, it is determined whether or not the distance Ln measured in step S110 is equal to or greater than a predetermined threshold value. If the distance Ln is equal to or greater than the threshold value, the process proceeds to the process of step S130. On the other hand, if the distance Ln is less than the threshold value, the precision measurement process is terminated. In this case, the correction amount of the mold is determined based on the distance Ln measured in step S110.

[0014] In step S130, the shim SP is replaced with the viscoplastic body VB, and the workpiece Wk is fixed to the precision measurement jig CF. This step is also referred to as the "second fixing step". The viscoplastic body VB is a material that can be plastically deformed more easily than the shim SP and is a material that plastically deforms reversibly by an external force. For example, the viscoplastic body VB is a material with a smaller elastic modulus than the shim SP. In the present embodiment, clay is adopted as the viscoplastic body VB. As shown in FIG. 3, the workpiece Wk is placed on the viscoplastic body VB arranged on the precision measurement jig CF. In the present embodiment, as shown in FIG. 4, the workpiece Wk is sandwiched and fixed between the clamp CP and the precision measurement jig CF via the viscoplastic body VB.

[0015] In step S140 (see FIG. 1), the viscoplastic body VB arranged in step S130 is deformed so that the shape of the workpiece Wk approaches the desired arrangement Tp more than the shape of the workpiece Wk in the first fixing step. More specifically, the positions of a plurality of predetermined second measurement locations on the workpiece Wk are deformed so as to approach the second target locations, which are the target positions of the respective plurality of second measurement locations of the workpiece Wk in the first fixing step. This step is also referred to as the "deformation step". The plurality of second measurement locations may include the first measurement location Pw. In the present embodiment, as shown in FIG. 4, when the second measurement location is defined at the lower first portion P1 of the workpiece Wk, the viscoplastic body VB is deformed so that the first portion P1 approaches the desired arrangement Tp and the upper second portion P2 of the workpiece Wk moves away from the desired arrangement Tp.

[0016] In step S150 (see FIG. 1), the deviation between the arrangement of the workpiece Wk and the desired arrangement Tp is measured. This step is also referred to as the "second measurement step". The deviation is a concept including the distance Ln measured in the first measurement step. In the present embodiment, the deviation is measured using a measuring device capable of non-contact dimension measurement.

[0017] In step S160, it is determined whether or not the deviation measured in step S150 satisfies a predetermined deviation condition. The deviation condition is a condition including that it is closer to the desired arrangement Tp than the shape of the workpiece Wk in the first fixing step. The deviation condition includes, for example, that all the determination distances are smaller than the corresponding determination distances in the first fixing step. The determination distance is the distance between the second measurement location and the second target location. When the deviation condition is satisfied, the accuracy measurement process is terminated. In this case, the correction amount of the mold is determined based on the deviation measured in step S150. On the other hand, when the deviation condition is not satisfied, the process returns to step S140. That is, the processes of steps S140 to S160 are repeatedly executed until the deviation condition is satisfied. That is, the viscoplastic body VB is deformed so as to satisfy the deviation condition. In this case, the correction amount of the mold is determined based on the deviation measured in step S150 immediately before.

[0018] According to the workpiece accuracy measurement method of the present embodiment described above, since the viscoplastic body VB is deformed to measure the dimensional accuracy, the work of processing the accuracy measurement jig CF and the shim SP can be omitted. Therefore, complicated work can be suppressed. In addition, since the workpiece Wk is brought closer to the desired arrangement Tp than when fixed using the shim SP, the repair area of the mold can be reduced in the preparation for manufacturing the mold used for press molding the workpiece Wk. Therefore, the cost of mold repair can be suppressed.

[0019] In addition, since a non-contact device is used as the contact device, it is possible to suppress the deformation of the viscoplastic body VB and the movement of the workpiece Wk when measuring the dimensions.

[0020] B. Second Embodiment: FIG. 5 is a flowchart showing an example of the workpiece accuracy measurement method in the second embodiment. The workpiece accuracy measurement method in the second embodiment is different from the processing method in the first embodiment in that it includes an analysis step S125 after step S120, and the other steps are the same as those in the first embodiment. Details of the analysis step will be described later.

[0021] In step S125, the shape of the viscoplastic body VB whose deviation satisfies a predetermined condition is analyzed. For example, the shape of the viscoplastic body VB that comes closest to the desired arrangement Tp is analyzed using a computer. More specifically, the shape with the smallest determination distance is obtained. This step is also referred to as the "analysis step". The shape with the smallest determination distance is, for example, the shape for which the sum of all determination distances is the smallest.

[0022] In step S140, it is deformed into the shape analyzed in step S125. In this case, since the viscoplastic body VB is deformed into a shape that satisfies the deviation condition, the process of step S160 may be omitted.

[0023] According to the workpiece accuracy measurement method of the second embodiment described above, since the viscoplastic body VB is deformed into the analyzed shape, it can be deformed into a shape that satisfies the deviation condition. Therefore, the working time can be shortened.

[0024] C: Other embodiments: (C1) In the above-described embodiment, the measuring device is a device that measures dimensions non-contact. However, it is not limited to this, and the measuring device may be a device that measures dimensions by contacting the workpiece Wk.

[0025] (C2) In the above-described embodiment, the viscoplastic body VB is clay. However, it is not limited to this, and the viscoplastic body VB may be a resin that cures by ultraviolet irradiation or a resin that cures by mixing two liquids of a main agent and a curing agent.

[0026] (C3) In the deformation step in the above-described embodiment, the viscoplastic body VB is deformed so that the determination distance becomes smaller than the determination distance in the first fixing step. However, it is not limited to this, and for example, the viscoplastic body VB may be deformed so that the area of the workpiece Wk that coincides with the desired arrangement Tp becomes larger.

[0027] (C4) In the above-described embodiments, the divergence condition is that all the determination distances are smaller than the corresponding determination distances in the first fixing step. However, it is not limited to this. For example, the divergence condition may be that the total reduction distance from the determination distances in the first fixing step is equal to or greater than a predetermined threshold distance. That is, the divergence condition may include that not all the determination distances need to be smaller than the corresponding determination distances in the first fixing step. Further, the divergence condition may be that all the determination distances are equal to or less than a predetermined ratio of the corresponding determination distances in the first fixing step.

[0028] (C5) In the second embodiment described above, the shape in which the determination distance is the smallest is the shape in which the sum of all the determination distances is the smallest. However, it is not limited to this. For example, weighting may be performed using the degree of priority for approaching the desired arrangement Tp set for each second measurement location in the determination distance, and the shape in which the weighted value is the smallest may be adopted.

[0029] The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be appropriately replaced or combined in order to solve the above-described problems or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

Explanation of Reference Numerals

[0030] CF… Precision measurement jig, CP… Clamp, SP… Shim, VB… Visco-plastic body, Wk… Workpiece

Claims

1. A workpiece accuracy measurement method, comprising: a first fixing step of arranging a shim between a workpiece manufactured by press forming and an accuracy measurement jig, and fixing the workpiece to the accuracy measurement jig; after the first fixing step, a first measurement step of measuring a distance between a position of a first measurement location predetermined in the workpiece and a first target position that is a position corresponding to the first measurement location in the workpiece of a target shape; a second fixing step of, when the distance is equal to or greater than a predetermined threshold value, replacing the shim with a viscoplastic body that is more easily plastically deformed than the shim, and fixing the workpiece to the accuracy measurement jig; a deformation step of deforming the viscoplastic body so that positions of a plurality of second measurement locations predetermined in the workpiece are closer to second target locations that are positions corresponding to the plurality of second measurement locations in the workpiece of the target shape than the positions of the plurality of second measurement locations in the workpiece in the first fixing step; a second measurement step of measuring a deviation between the shape of the workpiece and the target shape, including the distance, using a measuring device after the deformation step.

2. The workpiece accuracy measurement method according to claim 1, comprising: an analysis step of analyzing the shape of the viscoplastic body whose deviation satisfies predetermined conditions before the deformation step; the workpiece accuracy measurement method, wherein in the deformation step, the viscoplastic body is deformed into the shape analyzed in the analysis step.

3. The workpiece accuracy measurement method according to claim 1 or claim 2, wherein the measuring device is a device that measures dimensions in a non-contact manner.

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