JP3775293B2 - Clearance measurement method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a clearance measuring method for measuring a clearance between workpiece forming surfaces of a mold.
[0002]
[Prior art]
Conventionally, various methods for measuring the clearance between the workpiece forming surfaces of the mold have been implemented, and typical clearance measuring methods are shown in FIGS. 17 and 18. A case where the clearance of a mold divided into an upper mold 7 and a lower mold 8 is measured will be described as an example.
[0003]
The clearance measuring method shown in FIG. 17 is a method of measuring the lower die 8 with a metal wire 25 such as lead having a diameter larger than the clearance between the upper and lower dies 7 and 8 and having high malleability as shown in FIG. It is installed on the workpiece forming surface 6 to be worked.
[0004]
Next, as shown in FIG. 17B, the upper die 7 is lowered to the bottom dead center, the metal wire 25 is crushed between the workpiece forming surfaces 6 of the upper and lower dies 7, 8, and then the upper die 7 is raised. Then, the thickness of the metal wire 25 remaining on the workpiece molding surface 6 of the lower mold 8 is removed from the workpiece molding surface 6 of the lower mold 8 with a measuring instrument such as a micrometer 26 as shown in FIG. taking measurement. In this way, the clearance between the workpiece forming surfaces 6 of the upper and lower molds 7 and 8 is measured.
[0005]
The clearance measuring method shown in FIG. 18 is prepared by applying a paint 27 that easily adheres to a metal on the surface of a molded panel 26, positioning it on the workpiece molding surface 6 of the lower mold 8, and FIG. Install as shown in.
[0006]
Next, the upper mold 7 is lowered to the bottom dead center (see FIG. 18B), and a portion of the paint having a relatively small clearance from the upper mold 7 is attached to the work molding surface 6 of the upper mold 7. Next, as shown in FIG. 18C, the upper mold 7 is raised. On the work molding surface 6 of the upper mold 7, a large amount of paint adheres to a portion where the clearance with the lower mold 7 is small, and a small amount of paint adheres to a portion where the clearance is large. The clearance is qualitatively grasped by the density of the adhesion of the paint.
[0007]
[Problems to be solved by the invention]
However, in the former clearance measurement method, the crushed metal wire is removed from the mold and its thickness is directly measured, so deformation of the metal wire at the time of removal, deformation by applying measurement pressure, etc. Accordingly, the measurement accuracy is poor, and a large number of man-hours for measurement are required.
[0008]
In addition, the metal wire is installed only in a specific measuring part, and although the local clearance can be grasped, the distribution of the clearance on the curved surface of the workpiece forming surface cannot be grasped. In this case, it is necessary to repeat the measurement until the clearance on the curved surface can be grasped, and there is a problem that requires a great number of man-hours.
[0009]
In the latter clearance measurement method, the clearance can be qualitatively grasped by the density of the paint adhering to the work surface of the upper mold, so that the clearance distribution can be grasped but the clearance cannot be quantitatively grasped. Met.
[0010]
In addition, when there is a variation in the thickness of the paint applied to the molded panel, there is a problem that the variation in the measurement result also increases.
[0011]
Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a clearance measuring method capable of improving the clearance measurement accuracy and distribution accuracy.
[0012]
[Means for Solving the Problems]
  1st invention is the clearance measuring method which measures the clearance between the workpiece molding surfaces of a metal mold | die,A plurality of convex or block shapes with dimensions in the plate thickness direction larger than the clearance to be measuredMeasuring partRegularly arranged sheet-likePlace the measurement sample on one of the molds whose clearance is to be measured, close the molds whose clearance is to be measured to a predetermined position, and crush the measurement sample in the thickness direction,eachPerpendicular to the thickness direction of the measurement sectionsurfaceMeasure the amount of change in the direction dimension,surfaceThe clearance is obtained based on the amount of change in the directional dimension.
[0013]
  The second invention isIn the clearance measurement method to measure the clearance between the workpiece molding surfaces of the mold,Formed by measurement holes that penetrate in the thickness directionA plurality of measurement units arranged regularly, andFormed with a plate thickness dimension larger than the clearance to be measuredThe measured sample is placed on one of the molds whose clearance is to be measured, the molds whose clearance is to be measured are brought close to a predetermined position, and the measured sample is crushed in the plate thickness direction.Amount of change in opening width of measurement holeMeasure the amount of change in the opening width dimensionIt is characterized by obtaining clearance based onThe
[0014]
According to a third aspect, in the second aspect, the measurement hole of the measurement unit is formed such that the interval is larger than the dimension in the plate thickness direction.
[0016]
  First4The invention of the1In the invention ofMultiple regularly arrangedThe measurement part is based on the thickness direction dimension.surfaceIt is characterized by a large directional dimension.
[0017]
  First5The invention of theFrom 1In a fourth aspect of the invention, the measurement sample is made of aluminum, lead, or an alloy based on these that has good ductility, and has a yield point of 35 MPa or less.
[0018]
  First6The invention of theFrom 1In the fourth invention, the surface of the measurement sample is imaged, the measurement unit is discriminated by the image processing unit, and the measurement unit is analyzed by the analysis unit.surfaceThe directional dimension is measured over the entire image, and is displayed as a clearance distribution map corresponding to the coordinate position on the molding surface.
[0019]
  The seventh invention is theSecond or third inventionThe measurement sample having the measurement hole is set on a background having a lower brightness than the measurement sample.Surface isIt is converted into an image and the measurement unit is identified by the image processing means.Then, the dimension in the surface direction of the measuring part is measured over the entire image by the analysis means and displayed as a clearance distribution map corresponding to the coordinate position on the molding surface.It is characterized by that.
[0020]
The measurement sample is preferably coated with an anti-reflection matte paint before being imaged.
[0021]
  First8The invention of1st or 4thIn the invention, the measurement part of the measurement sample is composed of a plurality of plate-like members connected in parallel by thin connection parts.
[0022]
  First9The invention of1st or 4thIn the invention, the measurement part of the measurement sample is constituted by a plurality of block members that are regularly distributed and integrated on the surface of the sheet-like connecting member.
[0023]
  First10The invention of1st or 4thIn the invention, the measurement part of the measurement sample is composed of a plate-like member or a block-like member regularly arranged between the transparent sheets arranged at both ends in the plate thickness direction and held in position by adhesion to the transparent sheets on both sides. It is characterized by.
[0024]
  First11The invention of1st or 4thIn the invention, the measurement parts of the measurement sample are alternately arranged with the connection parts and bonded to each other.
[0025]
【The invention's effect】
  Therefore, in the first invention,A plurality of convex or block shapes with dimensions in the plate thickness direction larger than the clearance to be measuredMeasuring partRegularly arranged sheet-likePlace the measurement sample on one of the molds whose clearance is to be measured, close the molds whose clearance is to be measured to a predetermined position, and crush the measurement sample in the thickness direction,eachPerpendicular to the thickness direction of the measurement sectionsurfaceMeasure the amount of change in the direction dimension,surfaceSince the clearance is obtained based on the amount of change in the direction dimension, the dimension in the surface direction of the surface of the measurement sample is measured, and the measurement becomes easy.In addition, the dimensions in the surface direction after crushing a plurality of regularly arranged measurement parts change continuously according to the change in clearance, and in what part, to what extent, the clearance is outside the allowable range, The entire molding surface can be read, and the clearance distribution can be clearly discriminated.
[0026]
  In the second invention, formed by a measurement hole penetrating in the thickness directionA plurality of measurement units arranged regularly, andFormed with a plate thickness dimension larger than the clearance to be measuredThe measured sample is placed on one of the molds whose clearance is to be measured, the molds whose clearance is to be measured are brought close to a predetermined position, and the measured sample is crushed in the plate thickness direction.Amount of change in opening width of measurement holeMeasure the amount of change in the opening width dimensionSince the clearance is obtained based on the above, it is measured from the surface of the measurement sample and can be easily measured.Moreover, the opening width dimension after crushing the plurality of regularly arranged measurement holes continuously changes according to the change in the clearance, and to what extent is the clearance outside the allowable range, The entire molding surface can be read, and the clearance distribution can be clearly discriminated.Moreover, the measurement hole can be manufactured with relatively high accuracy by pressing or machining, and the measurement accuracy of the clearance can be improved. In addition, when the measurement holes are processed by press molding, a large amount of measurement sample can be manufactured at low cost.
[0027]
In the third aspect of the invention, in addition to the effect of the second aspect, the distance between the measurement holes of the measurement part is formed larger than the thickness direction dimension. The clearance can be measured with high accuracy.
[0029]
  First4In the invention of the1In addition to the effects of the invention ofMultiple regularly arrangedSince the dimension in the width direction of the measurement part is formed larger than the dimension in the thickness direction, the amount of change in the dimension in the thickness direction due to crushing can be enlarged to change in the width direction dimension, and the clearance can be measured with high accuracy.
[0030]
  First5In the invention of1st to 4thIn addition to the effects of the invention, since the measurement sample is formed of a material having a yield point of 35 MPa or less made of aluminum or lead having good ductility or an alloy based on these, transferability of the clearance to the measurement sample Can be high. When the yield point is 35 MPa or more, the springback becomes large and the transfer accuracy of the clearance is lowered.
[0031]
  First6The invention of theFrom 1In addition to the effect of the fourth invention, the measurement sample surface is imaged and displayed as a clearance distribution map corresponding to the coordinate position on the molding surface, so that the required correction amount of the mold is quantified on the free-form surface. Can be grasped and appropriate correction can be applied to the mold.
[0032]
  In the seventh invention,Second or third inventionIn addition to the effect of the measurement sample, the measurement sample with the measurement hole is set on a background with a lower brightness than the measurement sample.Surface isIt is converted into an image and the measurement unit is identified by the image processing means.Then, the dimension in the surface direction of the measuring part is measured over the entire image by the analysis means and displayed as a clearance distribution map corresponding to the coordinate position on the molding surface.Therefore, the brightness difference can be increased, the influence of the shadow caused by illumination can be eliminated, and the accuracy of the binarization process prior to the image analysis can be improved.
[0033]
Prior to the binarization process, by applying a matte paint to the measurement sample, it is possible to suppress the reflection of illumination generated from the edge of the measurement hole, and to further improve the accuracy of the binarization process.
[0034]
  First8In the invention ofFirst orIn addition to the effect of the fourth invention, the measurement part is composed of a plurality of plate-like members connected to each other by thin connection parts, and these plate-like members are arranged in parallel. The strip-shaped member is a striped pattern, and has a striped pattern in which the dimension in the width direction is continuously changed according to the clearance, so that the continuous change and distribution state of the clearance amount can be displayed more clearly.
[0035]
  First9In the invention ofFirst orIn addition to the effects of the fourth invention, a plurality of block members are regularly distributed on the surface of the sheet-like connecting member, so that the amount of clearance changes by comparing the areas of adjacent block members The distribution state can be displayed more clearly.
[0036]
  First10In the invention ofFirst orIn addition to the effects of the fourth invention, since the plate-like members or block-like members are regularly arranged between the transparent sheets arranged at both ends in the plate thickness direction, the clearance is compared by comparing the areas of adjacent block members. Changes in quantity and distribution state appear more clearly.
[0037]
  First11In the invention ofFirst orIn addition to the effects of the fourth invention, the measurement parts are arranged alternately with the connection parts and bonded to each other, so there is no restriction in the thickness direction dimension, and it can be arbitrarily molded from very thin to thick. is there.
[0038]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
[0039]
FIG. 1 shows an example of a measurement sample 1 used in a clearance measurement method to which the present invention is applied. The measurement sample 1 is mounted between the workpiece molding surfaces of the mold, crushed when the mold is closed, and plastically deformed according to the clearance between the molds.
[0040]
The measurement sample 1 is made of aluminum, lead, or an alloy based on these that has good ductility, that is, low yield point. The yield point of the material is as required within a range of 35 MPa (Pa is a unit of stress) or less in consideration of the pressing force of a machine that urges the mold to close the mold, for example, a press machine. Is selected. When the yield point is 35 MPa or more, the springback becomes large and the transfer accuracy of the clearance is lowered.
[0041]
The measurement sample 1 includes a plurality of measurement units 2 as plate-like members having a cross-sectional shape whose thickness is larger than the clearance to be measured and whose width is larger than the thickness. The plurality of measuring portions 2 are integrated at equal intervals on the connecting portion 3 whose plate thickness is thinner than the clearance to be measured, and is formed in a sheet shape as a whole.
[0042]
One surface of the measurement sample 1 is formed in a concavo-convex shape in which the measurement portion 2 has a convex shape, and only the connecting portion 3 has a groove shape. The surface of the measurement sample 1 is striped, and the other surface is formed in a planar shape by the connecting portion 3.
[0043]
The measurement sample 1 is installed with the other planar surface in contact with one of the opposing workpiece molding surfaces of a mold whose clearance is to be measured. When the other work forming surface is brought close as in the work forming, the measuring unit 2 is crushed between the work forming surfaces. Since the measuring part 2 is plate-shaped, it is plastically deformed by increasing its width direction dimension X. Since the connection part 3 is continuously arranged on the back surface of each measurement part 2, the change in the thickness direction dimension thereof is suppressed to a slight extent.
[0044]
The amount of increase in the width direction dimension X of the measuring unit 2 is proportional to the amount of crushing of the measuring unit 2 and is proportional to the amount of decrease in the clearance from the initial plate thickness direction dimension Z.
[0045]
In general, the clearance between the molds can be obtained by measuring the dimension Z in the plate thickness direction after the crushing of the measurement unit 2. In the clearance measuring method of the present invention, as described above, this clearance is measured by measuring the width direction dimension X of the measuring section 2 which increases in proportion to the amount of decrease from the initial thickness direction dimension Z.
[0046]
In this case, the clearance in the width direction X of the measurement unit 2 increases in proportion to the decrease in the clearance Z in the plate thickness direction dimension Z of the measurement unit 2 including the connection part 3 of the measurement sample 1, thereby providing a clearance. Can be measured indirectly.
[0047]
For this reason, if the thickness direction dimension Z and the width direction dimension Z of the measurement part 2 of the measurement sample 1 before being crushed are known, by measuring only the width direction dimension X of the measurement part 2 after being crushed, The plate thickness (clearance) of the measurement part 2 of the measurement sample 1 can be indirectly measured.
[0048]
The amount of increase in the width direction dimension X is set so that the width direction dimension X is larger than the plate thickness direction dimension Z of the measuring unit 2 as will be described later. It can be greatly amplified and deformed.
[0049]
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 an extreme case, the relative size can be determined visually. In a mold that requires uniform clearance, a molding surface portion with a large width direction dimension X of the measurement unit 2 is shaved by grinding or the like, and a molding surface portion with a small width direction dimension X of the measurement unit 2 is raised by overlaying or the like. It can be modified as follows.
[0050]
When the clearance to be measured is small, for example, smaller than the dimension Z in the plate thickness direction of the connecting portion 3 of the measurement sample 1, the upper die and the lower die are deformed so that only the measurement portion 2 of the measurement sample 1 is deformed. A spacer with a known thickness is sandwiched between parts that do not hinder clearance measurement. The measurement sample 1 is plastically deformed between the upper and lower molds regulated by the spacer.
[0051]
If the clearance to be measured is large, it can be dealt with by arbitrarily forming the measurement sample 1 having a large thickness of the connecting portion 3 correspondingly.
[0052]
FIG. 2 explains the concept of the clearance measurement method by crushing the measurement sample 1. FIG. 2A shows the measurement unit 2 of the measurement sample 1. The measurement part 2 of the shape of the solid line before crushing (the initial dimension of the plate thickness is Z0 and the initial dimension in the width direction is X0) is crushed by ΔZ in the plate thickness direction, and the width of the measurement unit 2 is ΔX / 2 in a dotted line shape. The plastic deformation state increased to both sides one by one.
[0053]
Generally, in plastic deformation of metals, Poisson's ratio (the elongation rate in the direction of the external force divided by the shrinkage in the vertical direction, which is a material-specific constant indicating the strain of the elastic body) is ν, and the strain in the direction to be crushed is When εZ and the strain in the width direction are εX, the Poisson's ratio ν is expressed by the following equation (1):
ν = | εX / εZ | ------------- (1)
Indicated. When this equation (1) is transformed, the following equation (2) is
| ΕX | = ν | εZ |
| ΔX / X0 | = ν | ΔZ / Z0 |
ΔZ = (1 / ν) | Z0 / X0 | · | ΔX | −− (2)
can get.
[0054]
According to the above equation (2), the plate thickness change amount ΔZ is proportional to the width change amount ΔX.
Further, when the equation (2) is modified, the following equation (3):
| ΔX / ΔZ | = ν | X0 / Z0 | ------ (3)
Is obtained.
[0055]
According to the above equation (3), the dimension enlargement magnification | ΔX / ΔZ | of the width direction change amount ΔX with respect to the plate thickness change amount ΔZ can be determined by the ratio between the width X0 and the height Z0 before being crushed.
[0056]
If the width direction dimension X is made larger than the sheet thickness direction (crushing direction) dimension Z, the amount of change ΔZ of the sheet thickness direction dimension Z is enlarged and amplified to the amount of change ΔX of the width direction dimension X. Can be made.
[0057]
The actual shape of the measurement sample 1 is the configuration shown in FIG. 2B including the measurement unit 2 and the connection unit 3, and the measurement unit 2 is crushed on the connection unit 3 in the manner indicated by the broken line. Therefore, the change constant ΔX in the width direction dimension X and the change amount ΔZ in the sheet thickness direction dimension Z, and the proportionality constant between the change amount ΔX in the width direction dimension X and the clearance are obtained experimentally.
[0058]
Next, the clearance measurement procedure using the measurement sample will be described with reference to FIG. 4, taking as an example the clearance measurement between the upper and lower molds of the press mold shown in FIG.
[0059]
The press die 5 shown in FIG. 3 includes an upper die (die) 7, a lower die (punch) 8 that constitutes the molding surface 6, and a blank holder 9 that holds the periphery of the panel between the upper die 7. The
[0060]
While the upper mold 7 is in the raised position, a work (panel) is placed on the upper surfaces of the lower mold 8 and the blank holder 9. Next, the upper die 7 is lowered, and the workpiece is press-molded by the molding surfaces 6 of the upper and lower dies 7 and 8 while sandwiching the periphery of the workpiece with the blank holder 9.
[0061]
This press die 5 is intended for forming a thin vehicle body panel of about 0.6 to 0.9 mm, for example. Since the clearance is as small as 1 mm or less, a spacer 10 is interposed between the outer peripheral sides of the upper mold 7 and the blank holder 9.
[0062]
4 (A) to 4 (C) are enlarged views of the molding surfaces 6 of the upper and lower molds 7 and 8 surrounded by circles in FIG. 3, and as shown in FIG. 4 (A), The measurement sample 1 is placed on the molding surface 6 of the lower mold 8 between the open upper and lower molds 7 and 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 pressurization, the upper die 7 is raised, and the width direction dimension X1 of the measurement part 2 of the measurement sample 1 crushed by the pressurization is measured as shown in FIG.
[0063]
At the time of this measurement, the thickness direction dimension Z0 and the width direction dimension X0 of the measurement part 2 of the measurement sample 1 and the clearance increment set by the spacer 10 are known in advance. Further, an allowable range of the width direction dimension X in which the clearance falls within the specified value range is set. By measuring only the width direction dimension X1 after being crushed, it is possible to read the entire molding surface 6 as to which part and to what extent the clearance is out of the allowable range. On the surface of the measurement sample 1, there are a plurality of striped patterns formed by the measurement unit 2, and the width direction dimension X <b> 1 continuously changes according to the change in clearance, so that the clearance distribution can be clearly determined.
[0064]
5 to 7 are experimental examples of the clearance measuring method of the present invention. Using the measurement sample shown in FIG. 5, the experiment shown in FIG. 6 was performed and the experimental results shown in FIG. 7 were obtained.
[0065]
A measurement sample 1 shown in FIG. 5 includes a connecting portion 3 having a width of 84 mm, a depth of 30 mm, and a plate thickness dimension of 0.3 mm, and a measuring portion having a width dimension of 4 mm and a plate thickness direction dimension of 0.5 mm integrally with the connecting portion 3. 2 was used with an interval of 6 mm.
[0066]
The equipment shown in FIG. 6 includes a measurement sample 1 shown in FIG. 5 between an upper block 11 and a lower block 12 in which a minimum distance is defined by spacers 10A and 10B having a thickness of 0.7 mm and a thickness of 0.6 mm. Install as shown in FIG. Next, as shown in FIG. 6B, pressurization (30 tons) is performed by the press machine 13, and after the pressurization, the change amount ΔZ of the plate thickness direction dimension Z and the width direction dimension X of the measurement unit 2 of the measurement sample 1 The relationship of the change amount ΔX was obtained.
[0067]
FIG. 7 shows an experimental result (a graph in which the vertical axis indicates the plate thickness change amount ΔZ and the horizontal axis indicates the width change amount ΔX). According to FIG. 7, it is confirmed that the portion plotted by the points is the individual data of the plate thickness change amount ΔZ and the width change amount ΔX, and there is a proportional correlation between the two as drawn diagonally by the solid line. did it. The width change amount ΔX with respect to the plate thickness change amount ΔZ can be an amplified value with a change magnification of 6 to 7, and the distribution of the clearance change can be easily confirmed visually.
[0068]
In the above embodiment, the following effects can be achieved. That is, a measurement sample 1 having a measurement part 2 having a plate thickness dimension larger than the clearance is placed on one work forming surface of a mold whose clearance is to be measured, the measurement part 2 is crushed in the plate thickness direction, and the measurement part 2 The width direction dimension X is measured, and the clearance is obtained based on the width direction dimension X. For this reason, the clearance information appears in the surface direction of the measurement sample 1, and the measurement is easy.
[0069]
Since the width direction dimension X of the measuring part 2 is formed larger than the sheet thickness direction dimension Z, the amount of change ΔZ of the sheet thickness direction dimension Z due to crushing can be amplified to the amount of change ΔX of the width direction dimension X, and the clearance can be measured with high accuracy. it can.
[0070]
Since the measurement sample 1 is made of aluminum, lead, or an alloy based on these materials having good ductility and having a yield point of 35 MPa or less, the transferability of the clearance to the measurement sample 1 can be improved. .
[0071]
The measuring part 2 is composed of a plurality of plate-like members connected to each other by a thin connecting part 3, and these plate-like members are arranged in parallel, so that the widthwise dimension X with a continuous clearance change changes. The change in the clearance amount and the distribution state appear more clearly.
[0072]
FIG. 8 shows another example of the measurement sample 1 used in the clearance measurement method of the present invention. The measurement part 2 was formed in a plate shape on the surface of the connection part 3 in FIG. In this embodiment, the measurement units 2 that are block members are regularly arranged. The block member has a quadrilateral shape (FIG. 8A) or a circular shape (FIG. 8B) on the surface of the connecting portion 3.
[0073]
In any structure, when the dimension Z in the plate thickness direction of the measuring part 2 is crushed, it expands to the periphery (in the entire circumferential direction) along the connecting part 3, so measure the enlarged dimension or area. Thus, the clearance can be measured in the same manner as the measurement sample 1 of FIG. Compared with the measurement sample 1 of FIG. 1, in the measurement sample 1 of this aspect, the deformation allowance in the plate thickness direction increases in size in the entire circumferential direction of the measurement unit 2, so the allowance for expansion in the width direction becomes slightly smaller. I hate it.
[0074]
In forming the measurement sample 1, there is a method in which the measurement unit 2 is pasted on the material plate to be the connection unit 3. However, although not shown, the shape portion corresponding to the measurement unit 2 has a concave surface. It can also be formed continuously in a strip shape with a forming roller.
[0075]
In this embodiment, the measurement parts 2 of the measurement sample 1 are regularly distributed and configured by a plurality of block members integrated with the sheet-like connection part 3. For this reason, the change of a clearance amount and a distribution state appear more clearly by comparing the width direction dimension or area of adjacent block members, ie, the measurement parts 2.
[0076]
FIG. 9 shows an example of still another measurement sample 1 used in the clearance measurement method of the present invention. In FIGS. 9A and 9B, a transparent sheet 15 is bonded to both surfaces of the measurement unit 2 to measure the measurement unit. 2 is held in position.
[0077]
As shown in FIG. 9 (A), the measurement unit 2 is arranged in a columnar shape or a block shape at equal intervals. In FIG. 9 (B), the measurement unit 2 having a spherical or cylindrical shape is arranged. They are arranged at equal intervals.
[0078]
Also in this example, the change in the dimension in the plate thickness direction of the measurement unit 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 space between the transparent sheets 15). It will be replaced by a change in the direction dimension).
[0079]
In the example shown in FIG. 9C, the measurement sample 1 is configured such that the measurement units 2 and the connection units 3 are alternately arranged and bonded to each other. The connecting portion 3 is a material that shrinks in the width direction as the measurement portion 2 is reduced in thickness in the plate thickness direction and increases in size in the width direction, and is deformed in the plate thickness reduction direction by the molding surface to reduce in the plate thickness direction. For example, it is formed with a rubber adhesive or the like.
[0080]
In the embodiment shown in FIG. 9, the measuring unit 2 is formed on a regularly arranged plate-like member or block-like member, and is held by adhesion to the transparent sheets 15 arranged at both ends in the plate thickness direction. For this reason, the change of a clearance amount and a distribution state appear more clearly by comparing the width direction dimension or the area of the adjacent measurement parts 2.
[0081]
In the embodiment shown in FIG. 9C, since the measuring parts 2 are alternately arranged with the connecting parts 3 and bonded to each other, there is no restriction in the thickness direction dimension, and any thickness from extremely thin to thick can be arbitrarily selected. Can be molded.
[0082]
FIG. 10 shows a clearance measurement method for measuring the clearance distribution of the measurement sample measured in each of the above-described modes. The clearance measurement method includes a CCD camera 18, an image processing means 19, and an analysis means 20.
[0083]
The CCD camera 18 converts the measurement sample 1 on the molding surface 6 of the lower mold 8 in a state where the measurement unit 2 is crushed for clearance measurement into a video signal. At that time, the surface states of the measurement part 2 and the connection part 3 of the measurement sample 1 are converted into image signals and captured.
[0084]
The image processing means 19 reproduces the surface shape of the measurement sample 1 on the image from the captured video signal. Specifically, first, binarization processing is performed to detect edges on both sides in the width direction of the measurement unit 2 of the measurement sample 1 and convert them into lines. Next, it is determined which 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.
[0085]
The processing of the image processing unit 19 forms the measurement sample 1 by adding a difference between the brightness of the surface of the connecting portion 3 and the brightness of the surface of the measuring portion 2 (for example, the measuring portion 2 is bright and the connecting portion 3 is dark). By doing so, it can be completed only by the binarization processing.
[0086]
The analysis unit 20 continuously measures the width-direction dimension X of the measurement unit 2 of the measurement sample 1 on the image reproduced by the image processing unit 19 while sequentially moving the position. Next, the clearance at each position is calculated from the measured width X of each position, and the clearance is displayed as a distribution map.
[0087]
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. For this reason, the necessary correction amount of the mold can be quantitatively grasped on the free-form surface, and appropriate correction can be applied to the mold.
[0088]
FIG. 11 shows another example of a measurement sample used in the clearance measurement method to which the present invention is applied. In the measurement sample 1 shown in FIGS. 1, 8, and 9, a convex or block-shaped measurement unit 2 is provided. This embodiment relates to a measurement sample 1A having a measurement hole 2A.
[0089]
In FIG. 11, a measurement sample 1A is formed on a plate-like plate made of a material having good extensibility similar to the above-described embodiments, and uniformly distributes a large number of measurement holes 2A penetrating in the plate thickness direction. It is arranged. In the illustrated example, the measurement holes 2A are arranged at equal intervals in the longitudinal direction of the measurement sample 1A and in the direction perpendicular thereto. The arrangement method is not limited to this, and for example, it may be arranged without staggering in a zigzag pattern. The dimension X2 between the measurement holes 2A is formed larger than the plate thickness direction dimension Z2 of the plate.
[0090]
The measurement hole 2A can be processed by punching by a press or machining by 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.
[0091]
Similar to the previous embodiment, the measurement sample 1A is mounted between the work molding surfaces 6 of the mold 5, crushed when the mold 5 is closed, and plastically deformed according to the clearance between the molds 5. In the deformation, the thickness direction dimension Z2 is reduced in accordance with the clearance, and the material volume corresponding to the reduction is extended to the measurement hole 2A which is a space, and the size of the measurement hole 2A, for example, the diameter thereof is reduced. .
[0092]
FIG. 12 shows the results of an experiment in which the measurement sample 1A is crushed with the equipment shown in FIG. 6, with the vertical axis representing the plate thickness variation ΔZ and the horizontal axis representing the diameter change obtained by subtracting the diameter after crushing. It is the graph which graduated quantity ΔD. According to FIG. 12, the portion plotted by the 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 diagonally by the solid line. it can. In this example, as indicated by the dotted auxiliary line, the thickness change amount ΔZ is 0.1 mm (between 0.2 and 0.3 mm in the figure) and the width change amount ΔD is 0.6 mm (0 in the figure). Between 3 and 0.9 mm). That is, the magnification of the change can be about 6 times, and the distribution of the clearance change can be easily confirmed visually.
[0093]
Therefore, if the thickness Z2 of the measurement sample 1A before crushing and the diameter D of the measurement hole 2A are known, the thickness of the measurement sample 1A is indirectly measured by measuring only the diameter of the measurement hole 2A after crushing. be able to.
[0094]
In the measurement sample 1A, when the plate thickness direction dimension Z2 is changed so as to be applied to a measurement object having a different clearance, the dimension X2 between the measurement holes 2A to be arranged is also the plate thickness direction dimension Z2. It changes according to change.
[0095]
In addition, the shape of the measurement hole 2A is a round hole in the above-described embodiment, but although not shown, it may be a polygonal square hole or an elliptical measurement hole.
[0096]
In this embodiment, in addition to the effects obtained in the first embodiment, the following effects can be achieved. That is, the measurement part is formed from a plurality of measurement holes 2A penetrating the measurement sample 1A in the plate thickness direction, and the clearance is measured based on the amount of change in the opening width dimension of the measurement hole 2A. It can be easily measured. Further, the measurement hole 2A can be manufactured with a relatively high accuracy by pressing or machining, and the measurement accuracy of the clearance 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.
[0097]
Since the interval between the plurality of measurement holes 2A of the measurement part is formed larger than the thickness direction dimension Z2, the amount of change in the thickness direction dimension due to crushing can be expanded to change the width direction dimension, and the clearance can be measured with high accuracy.
[0098]
FIG. 13 shows a clearance measurement procedure using the measurement sample 1A according to the embodiment of FIG. 11. The clearance distribution is first transferred to the measurement sample 1A, and then converted into electronic data by a CCD camera or scanner. Is done.
[0099]
In this clearance measurement procedure, first, in step S1, a measurement sample 1A is placed at a measurement site on one molding surface between upper and lower molds, for example. Next, in step S2, the measurement sample 1A is crushed by the upper and lower molds. In step S3, the upper mold is raised, and the crushed measurement sample 1A is taken out.
[0100]
Next, a matte paint is applied to the measurement sample 1A in step S4, and a black background is set on the measurement sample 1A in step S5. In step S6, the image of the measurement sample 1A is read into the CCD camera and captured as electronic data, and the image is binarized in step S7.
[0101]
FIG. 14 is an enlarged image of the measurement hole 2A in a state where the process of step S4 is not performed and the black background is not set in step S5, and FIG. 15 is an image obtained by binarizing the image of FIG. Show. 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.
[0102]
According to FIG. 14, a portion where the brightness is increased due to the reflection of the illumination is seen on the half-circumferential portion (portion (1) in the drawing) on one side of the edge of the measurement hole 2 </ b> A (portion (2) in the drawing). Further, since the background is not black, the brightness of the background (part (2) in the figure) and the brightness of the measurement sample 1A (part (3) in the figure) are approximated. In addition, a portion where the edge of the measurement hole 2A is shaded and becomes darker due to illumination is seen in the other half of the edge of the measurement hole 2A ((4) portion in the figure). The reflection part of the illumination, the low brightness difference with the measurement sample 1A, and the shadow caused by the illumination are both in the case of binarizing the image, the low brightness difference is ambiguous in the positive and negative, the reflection part is positive, The shadow is determined to be negative, and as shown in FIG. 15, the boundary becomes unclear at the portions (1) and (4).
[0103]
On the other hand, according to FIG. 16, since the matte paint is applied, the occurrence of illumination reflection is suppressed and the black background is set, so that the brightness difference from the measurement sample 1A can be increased, and the illumination The shadow of is generated on the black background. Therefore, when the image is binarized, the outline, that is, the boundary of the measurement hole 2A of the measurement sample 1A becomes clear.
[0104]
Next, in the binarized image, in step S8, the diameter of the measurement hole 2A is measured by image analysis software, and in step S9, the diameter change amount ΔD is calculated to calculate the clearance. In step S10, a clearance distribution map is created from the diameter variation ΔD of all the measurement holes 2A and displayed on a display or the like.
[0105]
In FIGS. 14 and 15 in which the application of matte paint and the black background are not set, the boundary of the measurement hole 2A becomes unclear, and the accuracy of the diameter measurement in step S8 deteriorates. On the other hand, the application of matte paint and a black background are set, and in FIG. 16, the boundary of the measurement hole 2A is clear, and the accuracy of diameter measurement in step S8 can be improved. For example, a flatbed scanner can be used in addition to the CCD camera for capturing the image in step S6.
[0106]
In this embodiment, the measurement sample 1A is set on a background having a lower brightness than the measurement sample 1A in step S5 and imaged in step S6, and the measurement unit uses the image processing means in the subsequent steps. Determined. For this reason, the brightness difference can be increased, and the influence of shadows due to illumination can be eliminated, and the accuracy of binarization processing prior to image analysis can be improved.
[0107]
Prior to the binarization process in step S7, the matte paint is applied to the measurement sample 1A in step S4, so that the reflection of illumination generated from the edge of the measurement hole 2A can be suppressed, and the accuracy of the binarization process is further improved. be able to.
[0108]
In the above embodiment, the measurement of the clearance for the press mold for molding the panel material has been described as the mold, but although not illustrated, the mold having a cavity such as a die-cast mold, a resin mold, etc. It can also be applied to forging dies.
[Brief description of the drawings]
FIG. 1 is a plan view (A) and a partial side view (B) of a measurement sample used in a clearance measurement method according to an embodiment of the present invention.
2A and 2B are schematic diagrams for explaining 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 sectional view of a mold showing an example to which the clearance measuring method of the present invention is applied.
FIG. 4 is a conceptual diagram showing the measurement procedure of the clearance measurement method of the present invention in order (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 the clearance measuring method of the present invention.
FIG. 6 is a schematic diagram showing the experimental equipment and showing a state (A) in preparation and a state (B) in test.
FIG. 7 is a graph showing experimental results.
FIG. 8 is a perspective view showing another example of a measurement sample used in the clearance measurement method of the present invention.
FIG. 9 is a cross-sectional view showing still another example of the measurement sample.
FIG. 10 is a system schematic diagram (A) showing a clearance measurement method for measuring the 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 measurement method according to another embodiment of the present invention.
FIG. 12 is a graph obtained by 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.
15 is a binarized image in 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 Measurement unit
2A Measuring hole (measuring part)
3 connecting parts
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 Analysis means

Claims (11)

In the clearance measurement method to measure the clearance between the workpiece molding surfaces of the mold,
One of the molds whose clearance is to be measured with a sheet-shaped measurement sample that is regularly or arranged with a plurality of measurement parts that are convex or block-shaped and have dimensions in the thickness direction larger than the clearance to be measured. Installed in
Crush the measurement sample in the plate thickness direction by bringing the molds whose clearance is to be measured closer to a predetermined position,
A clearance measuring method, comprising: measuring a change amount of a surface direction dimension perpendicular to a plate thickness direction of each measurement unit, and obtaining a clearance based on the change amount of the surface direction dimension. In the clearance measurement method to measure the clearance between the workpiece molding surfaces of the mold,
It is intended to measure the clearance of a measurement sample that is provided with a plurality of measurement parts regularly arranged with measurement holes penetrating in the thickness direction and whose thickness is larger than the clearance to be measured. Installed on one side of the mold,
Crush the measurement sample in the plate thickness direction by bringing the molds whose clearance is to be measured closer to a predetermined position,
A clearance measurement method characterized by measuring a change amount of an opening width dimension of each measurement hole and obtaining a clearance based on the change amount of the opening width dimension.   The clearance measurement method according to claim 2, wherein the measurement hole of the measurement part is formed with a distance larger than a dimension in the plate thickness direction.   The clearance measuring method according to claim 1, wherein the plurality of regularly arranged measurement units have a dimension in the surface direction larger than a dimension in the plate thickness direction.   5. The measurement sample according to claim 1, wherein the measurement sample is made of aluminum or lead having good extensibility or an alloy based on these materials, and has a yield point of 35 MPa or less. Clearance measurement method.   The measurement sample is imaged on the surface, the measurement unit is discriminated by the image processing unit, the surface direction dimension of the measurement unit is measured over the entire image by the analysis unit, and the clearance corresponding to the coordinate position on the molding surface The clearance measurement method according to any one of claims 1 to 4, wherein the clearance measurement method is displayed as a distribution map. The measurement sample having the measurement hole is set on a background having a lightness lower than that of the measurement sample, the surface is imaged, the measurement unit is discriminated by the image processing unit , and the surface direction dimension of the measurement unit is determined by the analysis unit. 4. The clearance measuring method according to claim 2, wherein the clearance is measured and displayed as a clearance distribution map corresponding to the coordinate position on the molding surface .   5. The clearance measurement according to claim 1, 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. Method.   The measurement part of the measurement sample is composed of a plurality of block members that are regularly distributed and integrated on the surface of the sheet-like connecting member. Clearance measurement method.   The measurement part of the measurement sample is composed of a plate-like member or a block-like member that is regularly arranged between the transparent sheets arranged at both ends in the plate thickness direction and held by adhesion to the transparent sheets on both sides. The clearance measuring method according to claim 1 or 4, characterized in that   5. The clearance measurement according to claim 1 or 4, wherein the measurement parts of the measurement sample are alternately arranged and connected to connecting parts that can be reduced and deformed in the surface direction and the plate thickness direction. Method.

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