JP2003075145A - Clearance measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clearance measuring method capable of improving measurement accuracy and distribution accuracy of a clearance. SOLUTION: In this clearance measuring method for measuring the clearance between work molding surfaces 6 of a die 5, a measuring sample 1 having a measuring part 2 having a larger board thickness size than the clearance is installed on the work molding surface 6 of the die 5 whose clearance is to be measured, and each die 5 whose clearance is to be measured is drawn close to a prescribed position to thereby crush the measuring part 2 of the measuring sample 1 in the board thickness direction, and the width direction size X1 of the measuring part 2 is measured, and the clearance is determined based on the width direction size X1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clearance measuring method for measuring a clearance between work forming surfaces of a mold.

[0002]

2. Description of the Related Art Conventionally, various methods for measuring the clearance between the work molding surfaces of a mold have been carried out, and typical clearance measuring methods are shown in FIGS. 17 and 18. The case of measuring the clearance of the mold divided into the upper mold 7 and the lower mold 8 will be described as an example.

In the clearance measuring method shown in FIG. 17, a metal wire 25 of lead or the like having a diameter larger than that of the clearance between the upper and lower dies 7 and 8 and having a high malleability is used as shown in FIG. 8 is installed on the work forming surface 6 to be measured.

Next, as shown in FIG. 17B, the upper die 7 is lowered to the bottom dead center to crush the metal wire 25 between the work forming surfaces 6 of the upper and lower dies 7 and 8, and then the upper die 7 is moved. To raise. Then, as shown in FIG. 17C, the thickness of the metal wire 25 remaining on the work forming surface 6 of the lower die 8 is removed from the work forming surface 6 of the lower die 8 with a measuring instrument such as a micrometer 26. taking measurement. In this way, the clearance between the work molding surfaces 6 of the upper and lower dies 7 and 8 is measured.

In the clearance measuring method shown in FIG. 18, the paint 2 that easily adheres to the metal on the surface of the molded panel 26 is used.
7 is applied and prepared, positioned on the work forming surface 6 of the lower die 8 and installed as shown in FIG.

Next, the upper die 7 is lowered to the bottom dead center (see FIG. 18 (B)), and the paint in a portion having a relatively small clearance with the upper die 7 is attached to the work forming surface 6 of the upper die 7. Next, as shown in FIG. 18C, the upper mold 7 is raised. On the work molding surface 6 of the upper die 7, a large amount of paint adheres to a portion having a small clearance with the lower die 7 and a small amount of paint to a portion having a large clearance. The clearance is qualitatively grasped by the density of the adhered paint.

[0007]

However, in the former clearance measuring method, since the crushed metal wire is removed from the mold and the thickness thereof is directly measured, the deformation of the metal wire at the time of removal, and The measurement accuracy is poor due to deformation and the like caused by applying the measurement pressure, and many man-hours are required for measurement.

In addition, since the metal wire is installed only in a specific measuring part, the local clearance can be grasped, but the distribution of the clearance on the curved surface of the work forming surface cannot be grasped, so that the upper and lower molds are In the correction processing of, it is necessary to repeat the measurement until the clearance on the curved surface can be grasped, and there is a problem that a large number of man-hours are required.

In the latter clearance measuring method,
Since the clearance is qualitatively grasped by the density of the paint adhering to the work forming surface of the upper mold, the clearance distribution can be grasped, but the clearance cannot be quantitatively grasped.

Moreover, when there is a variation in the thickness of the coating material applied to the molded panel, the variation in the measurement results also becomes large.

The present invention has been made in view of the above problems, and an object thereof is to provide a clearance measuring method capable of improving the clearance measuring accuracy and the distribution accuracy.

[0012]

A first aspect of the present invention is a clearance measuring method for measuring a clearance between work molding surfaces of a mold, in which a measurement sample having a measuring section is used for measuring the clearance. Installed on one side, crush the measurement sample in the plate thickness direction by bringing the molds to measure the clearance close to a predetermined position, and measure the amount of change in the width direction dimension perpendicular to the plate thickness direction of the measurement part, The clearance is obtained based on the amount of change in the widthwise dimension.

In a second aspect based on the first aspect, the measurement sample is formed with a plate thickness dimension larger than a clearance to be measured, and the measuring section penetrates the measurement sample in a plate thickness direction. It is characterized in that the clearance is formed based on the amount of change in the opening width dimension of the measurement hole.

A third invention is characterized in that, in the second invention, the measuring holes of the measuring section are formed such that the distance therebetween is larger than the dimension in the plate thickness direction.

A fourth invention is characterized in that, in the first invention, the measuring portion is formed such that a plate thickness dimension thereof is larger than a clearance to be measured.

A fifth aspect of the invention is characterized in that, in the fourth aspect, the measuring portion has a dimension in the width direction larger than a dimension in the plate thickness direction.

According to a sixth aspect of the invention, in the second or fourth aspect of the invention, the measurement sample is made of aluminum or lead having good ductility or an alloy having these as a base material, and has a yield point of 35 MPa or less. Is characterized by.

In a seventh aspect based on the second or fourth aspect, the surface of the measurement sample is imaged, the measuring section is discriminated by the image processing means, and the widthwise dimension of the measuring section is imaged by the analyzing means. It is characterized in that it is measured over the whole and displayed as a clearance distribution map corresponding to the coordinate position on the molding surface.

An eighth invention is characterized in that, in the second invention, the measurement sample is set on a background having a lower brightness than the measurement sample to be imaged, and the measuring section is discriminated by the image processing means. And

The measurement sample is preferably coated with an antireflection matte coating before being imaged.

According to a ninth aspect of the present invention, in the fourth aspect, the measuring portion of the measurement sample is composed of a plurality of plate-like members connected in parallel by thin connecting portions and arranged in parallel. Characterize.

In a tenth aspect based on the fourth aspect, the measurement portion of the measurement sample is composed of a plurality of block members which are regularly distributed and arranged on the surface of the sheet-like connecting member. It is characterized by being

In an eleventh aspect based on the fourth aspect, the measurement portion of the measurement sample is regularly arranged between the transparent sheets arranged at both ends in the plate thickness direction, and is held in position on both transparent sheets by adhesion. And a plate-shaped member or a block-shaped member.

A twelfth invention is characterized in that, in the fourth invention, the measurement portions of the measurement sample are arranged alternately with the connecting portions and are bonded to each other.

[0025]

According to the first aspect of the invention, therefore, a measurement sample having a plate thickness dimension larger than the clearance is set on one of the work molding surfaces of a mold for measuring the clearance, and the measurement sample is crushed in the plate thickness direction. Since it measures the width dimension of the measurement part provided on the measurement sample and obtains the clearance based on the width dimension, it measures the dimension of the surface of the measurement sample in the surface direction, and the measurement is easy. Become.

In the second invention, in addition to the effect of the first invention, the measurement section is formed by a measurement hole penetrating the measurement sample in the plate thickness direction, and the clearance is determined based on the variation of the opening width dimension of the measurement hole. Since it is obtained, it is measured from the surface of the measurement sample and can be easily measured. Further, the measurement hole can be manufactured with relatively high accuracy by press working or machining, and the clearance measuring accuracy can be improved. Moreover, when the measurement hole is processed by press molding, the measurement sample can be manufactured in large quantities and at low cost.

In addition to the effect of the second aspect of the invention, the third aspect of the invention forms the distance between the measurement holes of the measurement portion larger than the dimension in the thickness direction, so that the amount of change in the dimension in the thickness direction due to crushing is increased and the width is increased. It is possible to change the dimension in the direction and measure the clearance with high accuracy.

In addition to the effects of the first aspect of the invention, the fourth aspect of the invention is formed so that the thickness of the measurement portion is larger than the clearance to be measured, so that the widthwise dimension of the measurement portion to be crushed is measured. It is measured from the surface of the sample, and the measurement is easy.

In the fifth invention, in addition to the effect of the fourth invention, since the widthwise dimension of the measuring portion is formed to be larger than the thicknesswise dimension, the variation in the dimension in the thicknesswise direction due to crushing is enlarged to increase the widthwise direction. The size can be changed, and the clearance can be measured accurately.

In the sixth invention, in addition to the effects of the second or fourth invention, a sample to be measured is made of aluminum or lead having good ductility or an alloy having such a base material and having a yield point of 35 MPa or less. Since it is formed, the transferability of the clearance to the measurement sample can be improved.
When the yield point is 35 MPa or more, the spring back becomes large and the clearance transfer accuracy is reduced.

In addition to the effects of the second or fourth aspect of the invention, the seventh aspect of the invention displays the measurement sample surface as an image and displays it as a clearance distribution map corresponding to the coordinate position on the molding surface. The required amount of modification of the mold can be quantitatively grasped on the free-form surface, and the mold can be appropriately modified.

According to the eighth invention, in addition to the effect of the second invention, the measurement sample is set on a background having a lower brightness than the measurement sample to be imaged, and the measurement section is discriminated by the image processing means. Therefore, the difference in brightness can be increased, and the influence of the shadow caused by the illumination can be eliminated.
The accuracy of the binarization process can be improved.

By applying a matte paint to the measurement sample prior to the binarization process, it is possible to suppress the reflection of illumination generated from the edge of the measurement hole and further improve the accuracy of the binarization process.

In the ninth invention, in addition to the effect of the fourth invention, the measuring section is composed of a plurality of plate-like members connected to each other by thin connecting sections, and these plate-like members are arranged in parallel. Since it is arranged, the plate-shaped member has a striped pattern from the surface of the measurement sample, and the widthwise dimension changes continuously according to the clearance, so that the continuous change in the clearance amount and the distribution state can be displayed more clearly. .

In the tenth invention, in addition to the effect of the fourth invention, since a plurality of block members are arranged regularly on the surface of the sheet-like connecting member, the area of adjacent block members is increased. By comparing, the change in the clearance amount and the distribution state can be displayed more clearly.

According to the eleventh invention, in addition to the effect of the fourth invention, since the plate-shaped members or the block-shaped members are regularly arranged between the transparent sheets arranged at both ends in the plate thickness direction, the adjacent block members are arranged. By comparing the areas of the two, the change in the clearance amount and the distribution state can be seen more clearly.

In the twelfth invention, in addition to the effect of the fourth invention, the measuring portions are arranged alternately with the connecting portions and adhered to each other, so that there is no restriction in the dimension in the plate thickness direction and it is extremely thin. It is possible to form anything from thick to thick.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of a measurement sample 1 used in the clearance measuring method to which the present invention is applied. The measurement sample 1 is mounted between the work molding surfaces of the mold, crushed when the mold is closed, and plastically deformed according to the clearance between the molds.

The measurement sample 1 has good spreadability, that is,
Aluminum with a low yield point, or lead, or
An alloy having these as a base material is used as a material. The yield point of the material is, if necessary, within a range of 35 MPa (Pa is Pascal in a unit of stress) or less in consideration of a pressing force of a machine that urges a mold closing position, for example, a press machine. One of them is selected. When the yield point is 35 MPa or more, the spring back becomes large and the clearance transfer accuracy is reduced.

The measurement sample 1 has a plurality of measuring portions 2 as plate-like members having a plate thickness thicker than the clearance to be measured and having a cross-sectional shape with a width dimension larger than the plate thickness dimension. . The plurality of measuring parts 2 are provided on the connecting part 3 whose plate thickness is thinner than the clearance to be measured,
They are arranged at equal intervals and integrated to form a sheet as a whole.

On one surface of the measurement sample 1, the measuring portion 2 is formed in a convex shape, and only the connecting portion 3 is formed in an uneven shape in a groove shape. The surface of the measurement sample 1 has a striped shape, and the other surface is formed in a planar shape by the connecting portion 3.

The sample 1 to be measured is set by contacting one surface of the opposite mold forming surface of the mold whose clearance is to be measured with the other surface of the flat surface. When the other work forming surface is brought close to the work forming surface, the measuring unit 2 is crushed between the work forming surfaces. Since the measuring unit 2 has a plate shape, it is plastically deformed by increasing the width-direction dimension X thereof. Since the connecting portion 3 is continuously arranged on the back surface of each measuring portion 2,
The change in the dimension in the plate thickness direction can be suppressed only slightly.

The amount of increase in the widthwise dimension X of the measuring section 2 is
It is proportional to the amount of crushing of the measurement unit 2 and proportional to the amount of decrease in the clearance from the initial dimension Z in the plate thickness direction.

The clearance between the molds can be generally obtained by measuring the dimension Z in the plate thickness direction after the measurement unit 2 is crushed. In the clearance measuring method of the present invention, as described above, this clearance is measured by measuring the widthwise dimension X of the measuring portion 2 which increases in proportion to the amount of decrease from the initial thicknesswise dimension Z.

In this case, the widthwise dimension X of the measuring portion 2 increases in proportion to the reduction of the clearance with respect to the thicknesswise dimension Z of the measuring portion 2 including the connecting portion 3 of the measurement sample 1. The clearance can be measured indirectly.

Therefore, the measuring portion 2 of the measurement sample 1 before being crushed
If the dimension Z and the dimension Z in the plate thickness direction are known, by measuring only the dimension X in the width direction of the measurement unit 2 after being crushed,
The plate thickness (clearance) of the measurement portion 2 of the measurement sample 1 after being crushed can be indirectly measured.

The amount of increase in the widthwise dimension X is made larger by making the widthwise dimension X larger than the thicknesswise dimension Z of the measuring section 2.
As will be described later, the change in the width-direction dimension X can be greatly amplified and deformed more than the change in the plate-thickness-direction dimension Z.

The change in the width-direction dimension X is a change in the surface direction of the surface of the measurement sample 1 and is easy to measure. In extreme cases, the relative size can be visually determined. In a mold that requires a uniform clearance, the molding surface portion of the measuring portion 2 having a large widthwise dimension X is shaved by grinding or the like, and the molding surface portion of the measuring portion 2 having a small widthwise dimension X is raised by padding or the like. Can be modified as

The clearance to be measured is small,
For example, when the dimension is smaller than the dimension Z of the connecting portion 3 of the measurement sample 1 in the plate thickness direction, there is no hindrance to the measurement of the clearance between the upper die and the lower die so that only the measurement portion 2 of the measurement sample 1 is deformed. A spacer having a known thickness is sandwiched between the parts. The measurement sample 1 is plastically deformed between the upper and lower molds regulated by the spacer.

When the clearance to be measured is large, the measurement sample 1 having a large plate thickness dimension of the connecting portion 3 is arbitrarily formed correspondingly.

FIG. 2 illustrates the concept of a clearance measuring method by crushing the measurement sample 1. Figure 2
(A) shows the measurement part 2 of the measurement sample 1. Shape of solid line before crushing (Z0 is the initial dimension of plate thickness, X is the initial dimension in the width direction)
The measurement part 2 of 0) is crushed by ΔZ in the plate thickness direction, and the dotted line shows the plastic deformation state in which the width of the measurement part 2 increases by ΔX / 2 on both sides.

In general, in plastic deformation of metal, Poisson's ratio (constant peculiar to the strain of an elastic body, which is obtained by dividing the contraction rate in the vertical direction by the elongation rate in the direction of external force, which is a material-specific constant) is crushed in the direction ν. Strain is εZ, strain in the width direction is ε
Assuming that X, the Poisson's ratio ν is expressed by the following equation (1): ν = | εX / εZ | --------------------- (1) When this equation (1) is modified, the following equation (2) becomes: | εX | = ν | εZ | | ΔX / X0 | = ν | ΔZ / Z0 | ΔZ = (1 / ν) | Z0 / X0 | | ΔX |-(2) Obtained.

According to the above equation (2), the plate thickness change amount ΔZ
Is proportional to the width change amount ΔX. Further, by modifying the expression (2), the following expression (3), | ΔX / ΔZ | = ν | X0 / Z0 | ------- (3) is obtained.

According to the above equation (3), the dimension enlargement factor | ΔX / ΔZ | of the width direction change amount ΔX with respect to the plate thickness change amount ΔZ.
Can be determined by the ratio of the width X0 and the height Z0 before being crushed.

This means that if the dimension X in the width direction is made larger than the dimension Z in the plate thickness direction (crushing direction), the variation ΔZ of the dimension Z in the sheet thickness direction is expanded and amplified to the variation ΔX of the dimension X in the width direction. Can be deformed.

The actual shape of the measurement sample 1 is as follows:
2B, which is composed of a connection part 3 and a connection part 3,
The measuring part 2 is crushed on the connecting part 3 in a manner indicated by a broken line.
Therefore, the amount of change ΔX in the width direction dimension X and the thickness direction dimension Z
And the proportional constant of the clearance ΔX and the clearance in the widthwise dimension X are experimentally obtained.

Next, regarding the procedure for measuring the clearance using the above-mentioned measurement sample, the clearance measurement between the upper and lower molds of the press mold shown in FIG.
Follow the instructions below.

In the press die 5 shown in FIG. 3, an upper die (die) 7 forming a molding surface 6, a lower die (punch) 8 and a blank holder 9 for suppressing the panel periphery with the upper die 7. Composed of.

A work (panel) is placed on the upper surfaces of the lower die 8 and the blank holder 9 while the upper die 7 is in the raised position. Next, the upper die 7 is lowered, and while sandwiching the work periphery with the blank holder 9, the molding surfaces 6 of the upper and lower dies 7 and 8 are sandwiched.
Press-mold the work.

In the press die 5, for example, 0.
It is intended for the molding of thin body panels of 6 to 0.9 mm. Since the clearance is as small as 1 mm or less, a spacer 10 is provided between the outer periphery of the upper die 7 and the blank holder 9.
Is inserted.

FIGS. 4A to 4C are enlarged views of the molding surfaces 6 of the upper and lower molds 7 and 8 surrounded by circles in FIG. 3, and first shown in FIG. Thus, the measurement sample 1 is placed on the molding surface 6 of the lower mold 8 between the open upper and lower molds 7, 8. Next, as shown in FIG. 4B, the upper mold 7 is lowered to the bottom dead center, and the measurement sample 1 is pressurized to the clearance set by the spacer 10 (the clearance between the molds 7 and 8 increased by the spacer 10). After the pressure is applied, the upper mold 7 is raised, and as shown in FIG. 4C, the widthwise dimension X1 of the measurement portion 2 of the measurement sample 1 crushed by the pressure is measured.

At the time of this measurement, the dimension Z0 in the plate thickness direction, the dimension X0 in the width direction, and the spacer 10 of the measurement portion 2 of the measurement sample 1 are measured.
The amount of increase in clearance set in is known in advance. Further, an allowable range of the widthwise dimension X within which the clearance falls within the specified value range is set. Only by measuring the width-direction dimension X1 after crushing, it is possible to read at what part and to what extent the clearance is out of the allowable range for the entire molding surface 6. The surface of the measurement sample 1 has a plurality of striped patterns formed by the measurement unit 2, and the widthwise dimension X1 continuously changes according to the change in the clearance, so that the distribution of the clearance can be clearly discriminated.

FIGS. 5 to 7 are experimental examples of the clearance measuring method of the present invention. Using the measurement sample shown in FIG. 5, the equipment shown in FIG. 6 was used for the experiment, and the experimental results shown in FIG. 7 were obtained.

A measurement sample 1 shown in FIG. 5 is provided with a connecting portion 3 having a width of 84 mm, a depth of 30 mm and a plate thickness of 0.3 mm.
A measuring unit 2 having a width dimension of 4 mm and a plate thickness direction dimension of 0.5 mm was arranged at an interval of 6 mm so as to be integrated with the connecting portion 3.

The equipment shown in FIG. 6 is equivalent to the measurement sample 1 shown in FIG.
A spacer 10A having a plate thickness of 0.7 mm and a plate thickness of 0.6 mm,
It is installed as shown in FIG. 6 (A) between the upper block 11 and the lower block 12 in which the minimum distance is defined by 10B. Next, as shown in FIG. 6B, the press machine 13 pressurizes (30 tons), and after pressurization, the change amount ΔZ of the plate thickness direction dimension Z of the measurement part 2 of the measurement sample 1 and the width direction dimension X The relationship of the change amount ΔX was obtained.

FIG. 7 shows the experimental results (a graph in which the vertical axis represents the thickness variation ΔZ and the horizontal axis represents the width variation ΔX). According to FIG. 7, the portion plotted by dots is the individual data of the plate thickness change amount ΔZ and the width change amount ΔX, and it is confirmed that there is a proportional correlation between the two, as drawn by the solid line diagonally. did it. Width change amount ΔX with respect to plate thickness change amount ΔZ
Can be an amplified value with a magnification of change of 6 to 7 times, and the distribution of clearance change can be easily confirmed by visual observation.

In the above embodiment, the following effects can be obtained. That is, the measurement sample 1 provided with the measuring portion 2 having a plate thickness dimension larger than the clearance is installed on one work forming surface of the mold whose clearance is to be measured, and the measuring portion 2 is crushed in the plate thickness direction, The dimension X in the width direction is measured, and the clearance is obtained based on the dimension X in the width direction. Therefore, the clearance information appears in the surface direction of the measurement sample 1, and the measurement is easy.

The dimension X in the width direction of the measuring section 2 is set to the dimension Z in the plate thickness direction.
Since it is formed larger, the variation ΔZ of the dimension Z in the plate thickness direction due to crushing can be amplified to obtain the variation ΔX of the dimension X in the width direction, and the clearance can be accurately measured.

Since the measurement sample 1 is made of a material having good ductility such as aluminum or lead or an alloy having these as a base material and having a yield point of 35 MPa or less, the transferability of the clearance to the measurement sample 1 is increased. be able to.

Since the measuring part 2 is composed of a plurality of plate-like members connected to each other by the thin connecting parts 3, and these plate-like members are arranged in parallel, the widthwise dimension X in which the clearance changes continuously changes. It appears as a striped pattern that changes, the amount of clearance changes,
The distribution state appears more clearly.

FIG. 8 shows another example of the measurement sample 1 used in the clearance measuring method of the present invention, in which the surface of the connecting portion 3 of FIG. 1 is plate-like and the measuring portions 2 are arranged in parallel. However, in this embodiment, the measuring units 2 that are block members are regularly arranged. The block member is
The surface of the connecting portion 3 is formed in a quadrangle (FIG. 8A) or a circle (FIG. 8B).

In any of the structures, when the dimension Z in the plate thickness direction of the measuring section 2 is crushed, it expands to the periphery (in the entire circumferential direction) along the connecting section 3.
By measuring the area, the clearance can be measured similarly to the measurement sample 1 of FIG. In comparison with the measurement sample 1 of FIG. 1, in the measurement sample 1 of the present embodiment, the deformation allowance in the plate thickness direction expands in the entire circumferential direction of the measurement portion 2, so the expansion allowance in the width direction becomes slightly smaller. I dislike it.

In molding the measurement sample 1, there is also a method of sticking the measuring section 2 on the material plate which becomes the connecting section 3, but although not shown, the shape corresponding to the measuring section 2 is concave. It is also possible to continuously form into a strip shape with a forming roller having a surface.

In this embodiment, the measuring portions 2 of the measuring sample 1 are arranged in a regular distribution, and are composed of a plurality of block members integrated with the sheet-like connecting portion 3. Therefore, by comparing the widthwise dimensions or the areas of the adjacent block members, that is, the measurement units 2, the change in the clearance amount and the distribution state can be more clearly seen.

FIG. 9 shows an example of still another measurement sample 1 used in the clearance measuring method of the present invention, and FIG.
In (B), the transparent sheet 15 is adhered to both surfaces of the measuring unit 2 to hold the measuring unit 2 in position.

As shown in FIG. 9 (A), the measuring unit 2 has a columnar shape or a block shape and is arranged at equal intervals. In FIG. 9 (B), a spherical shape or a cylindrical shape is measured. The parts 2 are arranged at equal intervals.

Also in this example, the change in the plate thickness direction dimension of the measuring section 2 (in this case, the dimension in the direction in which the transparent sheets approach each other) changes in the width direction dimension (in this case, the transparent sheet 15). Will be replaced by a change in the space direction).

In the example shown in FIG. 9C, the measurement sample 1 is composed of the measuring portions 2 and the connecting portions 3 which are alternately arranged and adhered to each other. The connecting portion 3 is reduced in the width direction as the measuring portion 2 is reduced in the thickness direction dimension and is increased in the width direction dimension, and is deformed in the plate thickness reduction direction by the molding surface to be reduced in the plate thickness direction. For example, it is formed of a rubber adhesive or the like.

In the embodiment shown in FIG. 9, the measuring unit 2 is formed on a plate-shaped member or a block-shaped member arranged regularly, and is held in position by adhesion to the transparent sheets 15 arranged at both ends in the plate thickness direction. . Therefore, the change in the clearance amount and the distribution state can be more clearly shown by comparing the widthwise dimensions or the areas of the adjacent measuring units 2.

In the embodiment shown in FIG. 9C, the measuring portions 2 and the connecting portions 3 are alternately arranged and adhered to each other, so that there is no restriction in the dimension in the plate thickness direction, and from the extremely thin to the thick. It is possible to form anything as desired.

FIG. 10 shows a clearance measuring method for measuring the clearance distribution of the measurement sample measured in each of the above-mentioned modes, and includes a CCD camera 18, an image processing means 19, and
It is composed of the analysis means 20.

The CCD camera 18 converts the measurement sample 1 on the molding surface 6 of the lower mold 8 in the state where the measuring portion 2 is crushed for the clearance measurement into a video signal. At that time, the surface states of the measuring section 2 and the connecting section 3 of the measurement sample 1 are converted into image signals and captured.

The image processing means 19 reproduces the surface shape of the measurement sample 1 on the image from the captured video signal. Specifically, first, a binarization process is performed to detect edges on both sides in the width direction of the measurement unit 2 of the measurement sample 1 and convert the edges into lines. Then, it is determined which one of the regions divided by the line is the measurement unit 2, and the shape of the measurement sample 1 is reproduced on the image.

The processing of the image processing means 19 is performed by the connection unit 3.
Difference between the brightness of the surface of and the brightness of the surface of the measuring unit 2 (for example,
It is also possible to complete the measurement sample 1 only by forming the measurement sample 1 by attaching (the measuring unit 2 is bright and the connecting unit 3 is dark).

The analyzing means 20 is the image processing means 1.
The width-direction dimension X of the measurement portion 2 of the measurement sample 1 on the image reproduced in 9 is continuously measured while sequentially moving the position.
Then, the clearance at each position is calculated from the measurement width X at each position, and the clearance is displayed as a distribution chart.

In the embodiment shown in FIG. 10, the surface of the measurement sample 1 is imaged and displayed as a clearance distribution map corresponding to the coordinate position on the molding surface 6. Therefore, the necessary correction amount of the die can be quantitatively grasped on the free curved surface, and the die can be appropriately corrected.

FIG. 11 shows another example of the measurement sample used in the clearance measuring method to which the present invention is applied.
The measurement sample 1 shown in FIG. 9 is provided with a convex or block-shaped measurement portion 2, whereas in the present embodiment, the measurement sample 1A is provided with a measurement hole 2A.

In FIG. 11, the measurement sample 1A is formed on a plate-like plate made of a material having good spreadability, as in each of the above-mentioned embodiments, and has a large number of measurement holes 2A penetrating in the plate thickness direction. It is distributed and arranged like this. In the illustrated example, the measurement holes 2A are arranged at equal intervals in the longitudinal direction of the measurement sample 1A and the direction perpendicular thereto. The arrangement method is not limited to this, and for example, they may be arranged in a zigzag pattern. The dimension X2 between the measurement holes 2A is formed larger than the dimension Z2 in the plate thickness direction of the plate.

The measuring hole 2A can be processed by punching with a press or mechanical processing with a drill, and can be manufactured with relatively high accuracy by any method. When the measurement hole 2A is formed by press molding, the measurement sample 1A can be manufactured in large quantities and at low cost.

Similar to the previous embodiment, the measurement sample 1A is mounted between the work forming surfaces 6 of the mold 5, crushed when the mold 5 is closed, and plastically deformed according to the clearance between the molds 5. To be done. The deformation reduces the dimension Z2 in the plate thickness direction according to the clearance, and the material volume corresponding to the reduction is spread in the measurement hole 2A which is a space, and the size of the measurement hole 2A, for example, the diameter thereof is decreased. .

FIG. 12 shows the results of an experiment in which the measurement sample 1A was crushed by the equipment shown in FIG. 6, and the vertical axis represents the change in plate thickness ΔZ.
Is a graph in which the horizontal axis represents the diameter change amount ΔD obtained by subtracting the diameter after crushing from the diameter before crushing. According to FIG. 12, the portions plotted by dots are the individual data of the plate thickness change amount ΔZ and the width change amount ΔX, and it is confirmed that there is a proportional correlation between the two as depicted by the solid line. it can.
In this example, as shown by the dotted auxiliary line, the thickness variation Δ
Width change amount ΔD is 0.6 mm (0.3 to 0.9 mm in the figure) for Z of 0.1 mm (between 0.2 and 0.3 mm in the figure)
Between). That is, the change magnification can be set to about 6 times, and the distribution of the clearance change can be easily confirmed visually.

Therefore, the plate thickness Z2 of the measurement sample 1A before being crushed
If the diameter D of the measurement hole 2A is known, the measurement hole 2 after crushing
By measuring only the diameter of A, the plate thickness of the measurement sample 1A can be indirectly measured.

In the above measurement sample 1A, when the dimension Z2 of the plate in the plate thickness direction is changed so as to be applied to measurement objects having different clearances, the dimension X2 between the measurement holes 2A to be arranged is also the plate thickness direction. It is changed according to the change of the dimension Z2.

Further, although the measuring hole 2A is formed as a round hole in the above-mentioned embodiment, it may be formed as a polygonal square hole or an elliptical measuring hole, although not shown. Good.

In addition to the effects obtained in the first embodiment, the present embodiment can exhibit the effects described below. That is, the measurement part is formed by a plurality of measurement holes 2A penetrating the measurement sample 1A in the plate thickness direction.
Since the clearance is obtained based on the amount of change in the opening width dimension of A, it is measured from the surface of the measurement sample 1A and can be easily measured. Further, the measurement hole 2A can be manufactured with relatively high accuracy by press working or machining, and the clearance measuring accuracy can be improved. Moreover, when the measurement hole 2A is processed by press molding, the measurement sample 1A can be manufactured in large quantities and at low cost.

Since the interval between the plurality of measurement holes 2A in the measurement portion is formed larger than the dimension Z2 in the plate thickness direction, the amount of change in the dimension in the plate thickness direction due to crushing can be expanded to change the dimension in the width direction, and the clearance can be accurately measured. it can.

FIG. 13 shows a clearance measurement procedure using the measurement sample 1A of the embodiment shown in FIG.
The clearance distribution is first transferred to the measurement sample 1A and then judged as electronic data by a CCD camera or a scanner.

In this clearance measurement procedure, first, in step S1, the measurement sample 1A is placed, for example, at a measurement site on one molding surface between the upper and lower molds. Then
In step S2, the measurement sample 1A is crushed by the upper and lower molds, and in step S3, the upper mold is lifted and crushed.
Is taken out.

Then, in step S4, a matte paint is applied to the measurement sample 1A, and in step S5, a black background is set on the measurement sample 1A. In step S6, the image of the measurement sample 1A is read by the CCD camera and is captured as electronic data, and the image is binarized in step S7.

In FIG. 14, the process of step S4 is not performed,
FIG. 15 is an enlarged image of the measurement hole 2A in a state where the black background is not set in step S5, and FIG. 15 shows an image in which the image of FIG. 14 is binarized. FIG. 16 is an enlarged image of the measurement hole 2A in which the matte paint in step S4 is applied and the black background is set in step S5.

According to FIG. 14, a portion where the illumination is reflected and the brightness is increased can be seen in a half-circumferential portion (portion in the figure) on one side of the edge of the measurement hole 2A (portion in the figure). In addition, since the background is not black, the brightness of the background (portion in the figure) and the brightness of the measurement sample 1A (portion in the figure) are similar.
Moreover, in the half-circumferential portion (portion in the figure) on the other side of the edge of the measuring hole 2A, a portion where the edge of the measuring hole 2A is shaded by illumination and is darkened can be seen. The reflective part of these lights,
With respect to the low brightness difference with the measurement sample 1A and the shadow due to illumination, when the image is binarized, the low brightness difference is determined to be ambiguous between positive and negative, the reflection portion is determined to be positive, and the shadow is determined to be negative. As shown in FIG. 15, the boundary becomes unclear in the part.

On the other hand, according to FIG. 16, since the matte paint is applied, the occurrence of the reflection of the illumination is suppressed, and the black background is set, so that the difference in brightness from the measurement sample 1A can be increased, Moreover, the shadow of the illumination occurs on the black background portion. Therefore, when the image is binarized, the contour of the measurement hole 2A of the measurement sample 1A, that is, the boundary becomes clear.

Then, the binarized image is processed in step S
In 8, the diameter of the measurement hole 2A is measured by the image analysis software, and in step S9, the diameter change amount ΔD is calculated and the clearance is calculated. In step S10, a clearance distribution map is created from the diameter change amount ΔD of all the measurement holes 2A and displayed on a display or the like.

In FIGS. 14 and 15 where the coating of the matte coating and the black background are not set, the boundary of the measuring hole 2A becomes unclear, so that the accuracy of the diameter measurement in step S8 deteriorates. On the other hand, with the application of the matte paint and the black background set, the boundary of the measurement hole 2A is clear in FIG. 16, and the accuracy of the diameter measurement in step S8 can be improved. In addition to the CCD camera, for example, a flatbed scanner can be used to capture the image in step S6.

In this embodiment, measurement sample 1A is used.
Is set on a background having a lightness lower than that of the measurement sample 1A in step S5 and imaged in step S6.
In the subsequent steps, the measuring section is discriminated by the image processing means. For this reason, it is possible to increase the difference in lightness, eliminate the influence of the shadow caused by the illumination, and improve the accuracy of the binarization process prior to the image analysis.

Prior to the binarization process in step S7, by applying the matte paint to the measurement sample 1A in step S4, it is possible to suppress the reflection of the illumination generated from the edge of the measurement hole 2A, and to further improve the binarization process. The accuracy can be increased.

In the above embodiment, the measurement of the clearance with respect to the press mold for molding the panel material has been described as the mold, but it is not shown in the figure, but it is possible to use a mold having a cavity such as a die-cast mold or a resin mold. Also,
It can also be applied to forging dies.

[Brief description of drawings]

FIG. 1 is a plan view (A) and a partial side view (B) of a measurement sample used in a clearance measuring method according to an embodiment of the present invention.

2A and 2B are schematic diagrams illustrating a clearance measuring method of the present invention, in which FIG. 2A is a principle diagram and FIG. 2B is an actual diagram.

FIG. 3 is a mold sectional view showing an example of applying the clearance measuring method of the present invention.

FIG. 4 is a conceptual diagram showing the measurement procedure of the clearance measuring method of the present invention in the order of (A) to (C).

FIG. 5 is a plan view (A) and a partial side view (B) showing an example of a test piece for experimenting with the clearance measuring method of the present invention.

FIG. 6 is a schematic view showing experimental equipment, showing a state under preparation (A) and a state under test (B), respectively.

FIG. 7 is a graph showing the same experimental result.

FIG. 8 is a perspective view showing another example of the measurement sample used in the clearance measuring method of the present invention.

FIG. 9 is a sectional view showing still another example of the measurement sample.

FIG. 10 is a system schematic diagram (A) showing a clearance measuring method for measuring a clearance distribution of a measurement sample, and a schematic diagram (B) showing a processing procedure.

FIG. 11 is a front view (A) and a side view (B) of a measurement sample used in a clearance measuring method according to another embodiment of the present invention.

FIG. 12 is a graph obtained from an experiment showing the correspondence relationship between the width change amount ΔD and the plate thickness change amount ΔZ of the measurement sample shown in FIG. 11.

13 is a chart showing a clearance measurement procedure using the measurement sample of FIG.

14 is a captured image when steps 4 and 5 in the chart of FIG. 13 are omitted.

FIG. 15 is a binarized image in FIG.

FIG. 16 is a captured image in the chart of FIG.

FIG. 17 is a schematic diagram showing an example of a conventional technique together with procedures (A) to (C).

FIG. 18 is a schematic diagram showing another example of the prior art together with procedures (A) to (C).

[Explanation of symbols]

1,1A measurement sample 2 measuring section 2A measurement hole (measurement part) 3 connection 5 Press mold (mold) 6 Molding surface 7 Upper mold 8 Lower mold 9 Blank holder 10, 10A, 10B spacer 15 Transparent sheet 18 CCD camera 19 Image processing means 20 Analytical means

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Claims (12)

[Claims] 1. In a clearance measuring method for measuring a clearance between work molding surfaces of a mold, a measurement sample having a measuring section is installed on one of the molds for which the clearance is to be measured, and the clearance is measured. Crush the measurement sample in the plate thickness direction by bringing the molds closer to each other at a predetermined position, measure the amount of change in the width direction dimension perpendicular to the plate thickness direction of the measurement part, and clear the clearance based on the amount of change in the width direction. A method for measuring clearance, characterized by: 2. The measurement sample is formed with a plate thickness dimension larger than the clearance to be measured, and the measurement section is formed by a measurement hole penetrating the measurement sample in the plate thickness direction. The clearance measuring method according to claim 1, wherein the clearance is obtained based on a change amount of the opening width dimension. 3. The clearance measuring method according to claim 2, wherein the measuring holes of the measuring section are formed such that their intervals are larger than the dimension in the plate thickness direction. 4. The clearance measuring method according to claim 1, wherein the measuring section is formed with a plate thickness dimension larger than a clearance to be measured. 5. The clearance measuring method according to claim 4, wherein the measuring unit has a widthwise dimension larger than a thicknesswise dimension. 6. The measurement sample according to claim 2 or 4, wherein the material to be measured is made of aluminum or lead having good ductility or an alloy having such a base material as a material and has a yield point of 35 MPa or less. Clearance measurement method. 7. The surface of the measurement sample is imaged, the measuring section is discriminated by the image processing means, the widthwise dimension of the measuring section is measured by the analyzing means over the entire image, and the coordinates on the molding surface are measured. The clearance measuring method according to claim 2 or 4, wherein the distribution is displayed as a clearance distribution map corresponding to the position. 8. The clearance measurement according to claim 2, wherein the measurement sample is set on a background having a lower brightness than the measurement sample and imaged, and the measurement unit is discriminated by the image processing means. Method. 9. The clearance according to claim 4, wherein the measurement part of the measurement sample is composed of a plurality of plate-like members connected to each other by thin connection parts and arranged in parallel. Measuring method. 10. The measuring section of the measurement sample is constituted by a plurality of block members which are regularly distributed and arranged on the surface of the sheet-like connecting member to be integrated with each other. Clearance measurement method described. 11. The measurement part of the measurement sample is composed of a plate-shaped member or a block-shaped member that is regularly arranged between transparent sheets arranged at both ends in the plate thickness direction and is held in position by adhesion to the transparent sheets on both sides. The clearance measuring method according to claim 4, wherein the clearance measuring method is performed. 12. The clearance measuring method according to claim 4, wherein the measurement portions of the measurement sample are arranged alternately with the connecting portions and are adhered to each other.