JP2008264849A - Method for detecting abnormality of press die device of thin plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correctly detect any abnormality such as degradation and crack of a coating during the press forming in advance. <P>SOLUTION: When a thin plate 5 is press-formed by the relative movement of a punch 1 and a die 2, it is determined that a die is abnormal if the elastic strain generated inside an objective die for measurement by the press-forming and measured by strain measuring means 11, 12 installed inside the objective die for measurement while at least one of the punch 1 and the die 2 is the objective die for measurement, exceeds a predetermined range, or is lower than the predetermined range. According to the present invention, a die surface can be repaired at an adequate timing, and troubles such as scuffing and breakage of the die can be avoided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for detecting an abnormality of a die such as a punch or die that occurs during press molding in a press mold apparatus that press-molds a thin plate as a workpiece.

  The press forming of a thin plate using a press die apparatus is widely used in the field of manufacturing automobile parts. In general, the surface of a die such as a punch or die used in such a press mold apparatus is subjected to a coating treatment such as plating or lubricant application, but as the number of molding increases, The contact portion with the thin plate that is the workpiece is gradually worn out, and the coating process gradually deteriorates. When the coating process is deteriorated and the mold base material is exposed, a phenomenon such as mold galling due to a part of the thin plate as a workpiece being adhered to the mold surface occurs. Since the repair of the mold when mold squeezing occurs is expensive, it is desirable to repair the mold before generating the mold squeeze. In addition, when a crack or the like occurs in the mold due to fatigue or the like, if the molding is continued as it is, the crack may become larger and the mold may be greatly deformed, making it impossible to repair. Therefore, it is necessary to repair the mold at an appropriate timing.

Therefore, in the field of press molding, various measures have been conventionally taken in order to detect abnormalities in the mold. For example, Patent Document 1 discloses a technique in which a relationship between a change in operating state such as the speed of a mold at the time of punching or immediately after punching and the life of the mold is examined in advance, and the life of the mold is predicted based on the relationship. Is disclosed. Further, for example, Patent Document 2 discloses a technique for evaluating the mold galling property by sliding a steel plate imitating a workpiece on the mold surface while pressing it. Further, Non-Patent Document 3 discloses a technique in which a piezoelectric element is built in the vicinity of the shoulder portion of the die and the sliding characteristics of the thin plate are measured based on the compressive strain generated in the die shoulder.
JP-A-5-285889 JP 2006-255741 A Development of integrated high-strength steel sheet forming technology (development of mold friction sensor) ”, Proceedings of the 57th Joint Conference on Plastic Working (October 31 to November 2, 2006, Takaoka Chamber of Commerce and Industry Building) Published by Japan Society for Technology of Plasticity (October 17, 2006), pp. 165-166.

  However, in order to predict the life of a mold by the technique disclosed in Patent Document 1, it is necessary to investigate the relationship between the operating state of the mold and the life of the mold in advance. Therefore, it takes much time to collect data. Further, the technique of Patent Document 1 merely predicts the life of the mold, and it is impossible to accurately know the situation in which an abnormality has occurred in the mold and repair is necessary. On the other hand, with the technique of the above-mentioned Patent Document 2, although the galling property of the mold can be evaluated, it cannot be detected until the abnormality of the mold during molding occurs. Further, even if the frictional force between the die and the crease presser mold is measured as in Patent Document 3, it has not been possible to detect the abnormality of the mold during molding.

  The present invention has been created in view of such circumstances, and an object thereof is to enable accurate detection in advance of occurrence of an abnormality such as deterioration of a coating process or a crack during press molding.

  In order to achieve such an object, according to the present invention, when a thin plate is press-molded by the relative movement of a punch and a die, at least one of the punch and the die is a measurement target mold. A method of detecting an abnormality in a mold apparatus, wherein an elastic strain generated in the measurement target mold according to press molding is measured by a strain measurement unit installed in the measurement target mold. An abnormality detection method for a thin plate die apparatus is provided, wherein the abnormality of the measurement object mold is determined when the above range is exceeded or below a predetermined range.

  According to the present invention, the press die device further includes at least one of a pad and a crease presser die interlocking with the punch, and the punch, the die, the pad, and the crease presser die Provided is a method for detecting an abnormality in a thin plate press die device, wherein at least one of the die is a measurement target die.

  In the present invention, a plurality of strain measuring means for measuring elastic strain generated in at least one or more of the punch, die, pad, and wrinkle presser mold that are measurement target molds are installed, and the plurality of strain measuring means Among them, when the elastic strain measured by any one strain measuring means exceeds a predetermined range or falls below a predetermined range, it is determined that the punch, die, pad or wrinkle presser mold is abnormal. You may make it do. The strain measuring means is, for example, a piezo element or a strain gauge.

  According to the present invention, by measuring the elastic strain generated in the measurement target mold such as a punch or die, it is possible to accurately detect in advance that abnormalities such as deterioration of the coating process and cracks occur during press molding. Can be detected. As a result, the mold surface can be repaired at an appropriate timing, and problems such as mold galling and damage to the mold can be avoided.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view of a press mold apparatus for carrying out the abnormality detection method according to the first embodiment of the present invention. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the press mold apparatus, a punch 1 disposed above and a die 2 disposed below are disposed to face each other. In the illustrated example, a convex portion 3 is formed on the bottom surface in the cavity of the die 2, and a concave portion 4 corresponding to the convex portion 3 is formed on the bottom surface of the punch 1.

  In such a press mold apparatus, a flat thin plate 5 as a molding material is placed on the die 2, and the punch 1 and the die 2 are moved relatively straight in the vertical direction. By the relative linear movement of the punch 1 and the die 2 punch 1, the thin plate 5 is drawn into the cavity of the die 2 and is press-formed into a shape along the punch 1. In the example shown in the figure, the convex part 3 of the die 2 and the concave part 4 of the punch 1 make it possible to produce a container-shaped molded product 7 having a protrusion 6 on the bottom surface and an open top surface, as shown in FIG.

  In addition, when press-molding, the punch 1 may be lowered | hung and the die | dye 2 may be raised. Further, although an example in which the punch 1 is disposed above and the die 2 is disposed below is shown, the die 2 may be disposed above and the punch 1 may be disposed below.

  When press molding is performed in such a press mold apparatus, for example, as shown in FIG. 3, at the corner 4 a in the recess 4 on the lower surface of the punch 1, the thin plate 5 is formed at the upper corner 3 a of the projection 3 of the die 2 during molding. As a reaction force to bend into a shape along the shape, a force is applied from the thin plate 5 to press and spread the corner portion 4a to both sides during press molding. Thus, the force which spreads to both sides repeatedly acts on the corner portion 4a in the concave portion 4 on the lower surface of the punch 1 every time press forming is performed. Thereby, the crack 10 by fatigue may arise in the corner | angular part 4a in the recessed part 4 of the punch 1 lower surface with the increase in the frequency | count of shaping | molding. And when the crack 10 arises in the punch 1 in this way, if shaping | molding is continued as it is, the punch 1 will deform | transform greatly with the progress of the crack 10, and the punch 1 will be damaged.

  On the other hand, in the punch 1, an elastic strain is generated in the vicinity of the corner 4a due to a force acting to push the corner 4a to both sides during press molding. For example, when the elastic strain ε1 in the direction orthogonal to the crack 10 as shown in FIG. 3 is considered in the vicinity of the corner portion 4a, the elastic strain ε1 is the same as the corner portion 4a when the crack 10 is not generated. It is proportional to the force received.

  However, as shown in the figure, when even a slight crack 10 is generated in the corner 4a in the recess 4 on the lower surface of the punch 1, the elastic strain ε1 is reduced at a stretch by opening the crack 10. The reason for this is that the internal stress in the direction orthogonal to the crack 10 is not transmitted in the vicinity of the corner 4a due to the opening of the crack 10.

  Therefore, in the present invention, the strain measuring means 11 for measuring the elastic strain generated in the punch 1 is provided at a location where stress is particularly concentrated during press molding, such as the corner portion 4a in the recess 4 on the lower surface of the punch 1. By monitoring the change, it is detected at an early stage that a minute crack 10 has occurred in the punch 1.

  The strain measuring means 10 is provided inside the punch 1 in the vicinity of a location where stress is particularly likely to be concentrated during press molding, such as the corner 4a in the recess 4 on the lower surface of the punch 1. Further, in order to detect the occurrence of the crack 10, the direction in which the strain measuring means 10 is arranged is preferably a direction in which the elastic strain ε 1 that greatly changes depending on the presence or absence of the crack 10 can be measured. That is, for example, with respect to the crack 10 generated in the corner 4a in the recess 4 on the lower surface of the punch 1 as shown in FIG. It is desirable to arrange the means 11.

  Further, when press molding is performed in such a press mold apparatus, for example, as shown in FIG. 4, the thin plate 5 is drawn into the space between the punch 1 and the die 2 (clearance) immediately after passing through the shoulder 2 b of the die 2. To go. In press forming that performs drawing, a large frictional force is generated between the thin plate 5 and the thin plate 5 at the shoulder 2b of the die 2 in which the thin plate 5 is drawn into the clearance between the punch 1 and the die 2. Usually, the surface of the die 2 is subjected to a coating process such as plating or lubricant application, but the friction force repeatedly acts on the shoulder portion 2b of the die 2 every time press molding is performed, so that the number of moldings increases. As a result, the coating process on the surface of the shoulder 2b of the die 2 gradually deteriorates. When the coating process on the surface of the shoulder 2b of the die 2 is peeled off and the base metal is exposed, a phenomenon such as mold galling due to a part of the thin plate 5 sticking to the surface of the shoulder 2b of the die 2 occurs. .

  On the other hand, in the inside of the die 2, elastic strain is generated in the vicinity of the shoulder portion 2 b by receiving a frictional force from the thin plate 5 during press molding. For example, when considering an elastic strain ε2 in the vertical direction (the direction of relative straight movement of the punch 1 and the die 2) as shown in FIG. 4 in the vicinity of the shoulder portion 2b, the elastic strain ε2 is applied to the die during press molding. 2 is proportional to the frictional force that the shoulder 2 b receives from the thin plate 5. If the coating treatment on the surface of the shoulder portion 2b of the die 2 deteriorates as the number of moldings increases, the frictional force that the shoulder portion 2b of the die 2 receives from the thin plate 5 also increases in proportion thereto, and the elastic strain ε2 is increased. It will increase.

  Therefore, in the present invention, strain measuring means 12 for measuring the elastic strain generated in the die 2 is provided at a location where stress is particularly concentrated due to friction with the thin plate 5 during press molding, such as the shoulder portion 2b of the die 2. By monitoring the change, it is detected at an early stage that the coating process on the surface of the shoulder portion 2b of the die 2 has deteriorated.

  The strain measuring means 12 is provided inside the die 2 in the vicinity of a portion where stress is particularly likely to be concentrated due to friction with the thin plate 5 during press molding, such as the shoulder portion 2b of the die 2. In order to detect an increase in the frictional force received from the thin plate 5, the direction in which the strain measuring means 12 is arranged is a direction in which the elastic strain ε2 generated by the frictional force with the thin plate 5 can be measured in the vicinity of the shoulder 2b. Is good. That is, for example, with respect to the frictional force generated near the shoulder 2b as shown in FIG. 4, the strain measuring means 12 can be arranged in the vertical direction, which is the direction of the relative straight movement of the punch 1 and the die 2. desirable.

  When the press mold apparatus shown in FIG. 1 is used for press molding, the strain measuring means 11 measures the elastic strain generated inside the punch 1 in the vicinity of the corner 4a in the recess 4 on the lower surface of the punch 1. The occurrence of the crack 10 in the corner portion 4a can be accurately detected at an early stage. In this case, a predetermined range is determined in advance for the elastic strain ε1 measured by the strain measuring means 11, and it is determined that the crack 10 has occurred when the elastic strain ε1 falls below the predetermined range during press molding. Can do.

  Further, by measuring the elastic strain generated inside the die 2 in the vicinity of the shoulder portion 2b of the die 2 with the strain measuring means 12, it is possible to accurately detect at an early stage that the coating process on the surface of the shoulder portion 2b has deteriorated. Can do. Also in this case, a predetermined range is determined in advance for the elastic strain ε2 measured by the strain measuring means 12, and it is determined that the coating process has deteriorated when the elastic strain ε2 exceeds the predetermined range during press molding. be able to.

  As a result, during press molding, abnormalities in the mold (punch 1 and die 2) such as generation of cracks 10 and deterioration of coating processing can be accurately detected at an early stage of generation. And when abnormality is detected, what is necessary is just to remove a metal mold | die, perform coating processing, such as plating and lubricant application, cutting of the crack 10 part, and overlaying repair. In this way, the mold can be repaired at an appropriate timing, and good press molding without molding defects can be performed while avoiding problems such as mold galling and mold breakage in advance.

  For example, a piezo element or a strain gauge can be used as the strain measuring means 11 provided inside the punch 1 and the strain measuring means 12 provided inside the die 2. FIG. 5 is an explanatory diagram in the case where the measuring means 11 composed of such a piezo element, a strain gauge or the like is attached to the inside of the punch 1.

  In FIG. 5, the strain measuring means 11 is inserted into the punch 1 by inserting the strain measuring means 11 into the bottom of the hole formed in the punch 1, and then the hole is closed with a bolt 15. A lead wire 16 for taking out a detection signal from the strain measuring means 11 passes through the bolt 15 and is drawn to the outside. In this case, the strain measuring means 11 is preferably arranged at a position of a depth of about 4 to 30 mm from the surface of the punch 1 that contacts the thin plate 5.

  In addition, although the mounting structure of the strain measuring means 11 provided inside the punch 1 has been described, the same applies to the strain measuring means 12 provided inside the die 2.

  FIG. 6 is a schematic explanatory view of a press die apparatus according to the second embodiment of the present invention. The molded product is a U-shaped cross-section straight part. The press mold apparatus shown in FIG. 6 is a system that performs press molding while pressing the thin plate 5 between the pad 20 and the punch 1. In the illustrated example, a pair of convex portions 21 projecting upward on both sides of the upper surface of the pad 20 are formed continuously in the longitudinal direction (perpendicular to the plane of the drawing). The convex part 22 for pushing the thin plate 5 into is similarly formed.

  When press molding is performed with this press mold apparatus, a large frictional force is generated between the thin plate 5 and the inner corner 21a of the convex portion 21 formed on the upper surface of the pad 20, as shown in FIG. Usually, the surface of the pad 20 is subjected to a coating process such as plating or lubricant application, but such a frictional force is applied to the inner corner 21a of the convex portion 21 formed on the upper surface of the pad 20 every time press molding is performed. Since it acts repeatedly, the coating process on the surface of the inner corner 21a gradually deteriorates as the number of molding increases. When the coating process on the surface of the inner corner 21a is peeled off and the base metal is exposed, a phenomenon such as mold galling due to a part of the thin plate 5 sticking to the surface of the inner corner 21a occurs.

  Therefore, in the present invention, in the vicinity of the portion where stress is particularly likely to be concentrated due to friction with the thin plate 5 during press molding, such as the inner corner portion 21a of the convex portion 21 formed on the upper surface of the pad 20, the inside of the convex portion 21 is provided. Strain measuring means 25 for measuring the generated elastic strain is provided. The installation direction of the strain measuring means 25 is preferably the horizontal direction so that the strain generated by the frictional force in the horizontal direction can be measured on the paper surface of FIG. Then, by monitoring a change in elastic strain generated inside the convex portion 21 by the strain measuring means 25, it is detected at an early stage that the coating process on the inner corner portion 21a of the convex portion 21 has deteriorated. Also in this case, a predetermined range is determined in advance for the elastic strain measured by the strain measuring means 25, and it is determined that the coating process has deteriorated when the elastic strain exceeds the predetermined range during press molding. it can.

  FIG. 8 is a schematic explanatory view of a press die apparatus according to the third embodiment of the present invention. The press mold apparatus of FIG. 8 is a system that performs press molding while applying a wrinkle press load to the flange portion of the thin plate 5 by the wrinkle press mold 30. In the illustrated example, a convex portion 31 for pressing the upper surface of the thin plate 5 is formed on the lower surface of the crease presser die 30 which is a measurement target die.

  When press molding is performed with this press mold apparatus, a large frictional force is generated between the lower surface of the convex portion 31 formed on the lower surface of the wrinkle presser mold 30 and the thin plate 5 as shown in FIG. Usually, the surface of the crease presser mold 30 is subjected to a coating process such as plating or lubricant application. However, such a frictional force repeatedly acts on the lower surface of the convex portion 31 every time press molding is performed. As the number of times increases, the coating process on the lower surface of the convex portion 31 gradually deteriorates. And when the coating process of the lower surface of the convex part 31 is peeled off and the base metal is exposed, a phenomenon such as mold galling due to a part of the thin plate 5 sticking to the lower surface of the convex part 31 occurs.

  Therefore, in the present invention, the elasticity generated inside the convex portion 31 in the vicinity of a portion where stress is particularly concentrated due to friction with the thin plate 5 during press molding, such as the convex portion 31 formed on the lower surface of the crease presser die 30. Strain measuring means 35 for measuring strain is provided. Then, by monitoring a change in elastic strain generated inside the convex portion 31 by the strain measuring means 35, it is detected at an early stage that the coating process on the lower surface of the convex portion 31 has deteriorated. Also in this case, a predetermined range is determined in advance for the elastic strain measured by the strain measuring means 35, and it is determined that the coating process has deteriorated when the elastic strain exceeds the predetermined range during press molding. it can. The installation direction of the strain measuring means 35 is preferably the horizontal direction so that the strain generated by the frictional force in the horizontal direction can be measured on the paper surface of FIG.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to this example. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to. For example, in the press mold apparatus shown in FIG. 1, the lower outer corner 40 and the lower inner corner 41 of the punch 1 and the lower inner corner 41 of the die 2 can be used as locations where abnormalities such as coating processing deterioration and cracks are likely to occur in the mold. The upper surface corner 3a of the convex portion 3 formed on the inner bottom surface of the cavity, the upper surface corner 42 of the convex portion 22 formed on the punch 1 in the press mold apparatus shown in FIG. 6, and the press metal shown in FIG. A lower surface corner 43 of the punch 1 in the mold apparatus is also conceivable. An abnormality of the mold may be detected by disposing strain measuring means such as a piezo element, a strain gauge or the like at those locations and measuring the elastic strain generated during press molding. It is preferable that the installation direction is the same as the frictional force generated at the installation position because distortion can be measured with the highest sensitivity.

  Ironing was performed by the press mold apparatus described in FIG. The relationship between the number of molded products produced and the elastic strain ε1 measured by the strain measuring means 11 is shown in FIG. FIG. 11 shows the relationship between the number of molded products produced and the elastic strain ε2 measured by the strain measuring means 12. In Example 1, the thin plate 5 is a mild steel plate having a thickness of 2.0 mm, and the size of the molded product is 280 mm square. Strain gauges were used as the strain measuring means 11 and 12. As shown in FIG. 3, the strain measuring means 11 on the left side in FIG. 1 is below the crack 10 expected in the direction of 45 degrees to the right and 45 degrees to the left of the corner 4a on the inside of the punch 1. The punch 1 was provided at a depth of 5 mm at the closest part from the inner surface of the punch 1. Further, in FIG. 1, the strain measuring means 11 on the right side is a crack (not shown) that is expected in the 45 ° right diagonal direction at the corner (in the right side of FIG. 1) of the inside of the punch 1. Further above, at a position closest to the inner surface of the punch 1 at a depth of 6 mm. Further, as shown in FIG. 4, the strain measuring means 12 is provided in the vertical direction at 8 mm from the upper surface of the die 2 and at a depth of 5 mm from the surface of the vertical wall portion of the die 2. The radius of curvature of the corner 4a inside the punch 1 is 5 mm, the radius of curvature of the shoulder 2b of the die 2 is 4 mm, the radius of curvature of the upper corner 3a of the convex 3 is 3 mm, and the convex 3 is 100 mm square. The protrusion 6 of the molded product has a radius of curvature of 20 mm, a height of 12 mm, an outer substantially square with a radius of curvature of 50 mm, and a height of 40 mm.

  As shown in the measurement example of the strain measurement means 11 on the left side in FIG. 10, the elastic strain ε1 measured by the strain measurement means 11 exceeds 160 με until the number of molded products produced is approximately 1400. When the number of molded products exceeds approximately 1400, the elastic strain ε1 measured by the strain measuring means 11 may be 160 με or less, and then the number of molded products produced is approximately 1600, and the strain measuring means. The elastic strain ε1 measured by No. 11 was reduced at a stretch, and at this time, a crack 10 occurred in the corner 4a on the left side of the paper surface shown in FIG.

In the case of the first embodiment, when the elastic strain ε1 measured by the strain measuring means 11 becomes 160 με or less, for example, cutting of the corner portion 4a in the concave portion 4 on the lower surface of the punch 1 and overlay repair are appropriately performed. Just do it.
In the first embodiment, two strain measuring means 11 are installed. However, when only one strain measuring means 11 is installed, cracks in the measurement target mold can be detected in the same manner.

  Further, as shown in FIG. 11, the elastic strain ε2 measured by the strain measuring means 12 is less than 120 με until the number of molded products is about 130, but the number of molded products is about 130. When the elastic strain ε2 measured by the measuring means 12 exceeds 120 με, the number of molded products produced is about 170, and the elastic strain ε2 measured by the measuring means 12 is large at once. At this time, mold galling occurred on the surface of the shoulder 2b of the die 2 on the right side of the paper surface shown in FIG.

  In the case of the first embodiment, when the elastic strain ε2 measured by the measuring means 12 is 120 με or more, for example, a coating process such as plating of the shoulder portion 2b of the die 2 or application of a lubricant may be appropriately performed.

Forming was performed by the press die apparatus described in FIG. The relationship between the number of molded products produced and the elastic strain measured by the strain measuring means 25 is shown in FIG. In Example 2, the thin plate 5 is a high-tensile steel plate having a thickness of 1.6 mm, and the molded product is a U-shaped straight section having a width of 90 mm, a height of 50 mm, and a length of 200 mm. The width of the convex portion 22 is 62 mm, the height is 11 mm, the radius of curvature is 4.6 mm in both the upper and lower sides, and the radius of curvature of the outer corner portion 42 of the punch 1 is 6 mm. Further, the curvature radius of the inner corner 21a of the convex portion 21 of the pad 20 is 3 mm in both upper and lower sides, the width of the convex portion 21 is 10.7 mm, and the height is 11 mm.
In FIG. 6, the left and right strain measuring means 25 are piezo elements. As shown in FIG. 7, the left and right strain measuring means 25 are provided in the horizontal direction at a depth of 7 mm from the surface of the vertical wall portion of the inner corner portion 21 a of the pad 20 and a depth of 5 mm from the upper surface of the convex portion 21 of the pad 20. It was.

As shown in the measurement example of the strain measurement means 25 on the left side in FIG. 12, the elastic strain measured by the measurement means 25 starts to increase greatly after the production number of molded products reaches about 300, and the coating process is performed. Deterioration was detected. In the case of the second embodiment, it can be detected that the coating process of the inner corner portion 21a of the convex portion 21 formed on the upper surface of the pad 20 has deteriorated due to the fact that the elastic strain measured by the measuring means 25 has started to increase greatly. . When deterioration of the coating process is detected as described above, a coating process such as plating of the convex portion 21 or application of a lubricant may be appropriately performed. In the case of the second embodiment, the convex portion 21 may be repaired when the elastic strain measured by the measuring means 25 is, for example, 90 με or more. As a result, it is possible to repair the pad 20 before die scoring occurs.
In the second embodiment, two strain measuring means 25 are installed. However, even when only one strain measuring means 25 is installed, the galling of the measurement target mold can be detected in the same manner.

Drawing was performed by the press die apparatus described in FIG. The relationship between the number of molded products produced and the elastic strain measured by the strain measuring means 35 is shown in FIG. In Example 3, the thin plate 5 is a high-tensile steel plate having a plate thickness of 1.0 mm, and the molded product is a hat cross-sectional component having a web width of 120 mm, a depth of 50 mm, and a length of 180 mm. As shown in FIG. 9, the convex part 31 had a diameter of 10 mm and a height of 4 mm, and was provided at a position 35 mm from the vertical wall part. The radius of curvature of the punch 1 is 9 mm, and the radius of curvature of the die 2 is 10 mm both at the top and bottom.
In FIG. 9, strain gauges are used as the left and right strain measuring means 35. As shown in FIG. 9, the left and right strain measuring means 35 is 7 mm deep from the apex of the convex portion 31 of the crease presser mold 30 and horizontally from the starting point of the convex portion 31 (side closer to the punch 1). (Right side of the drawing) It was provided at a position of 4 mm.

  As shown in the measurement example of the strain measuring means 25 on the left side in FIG. 13, the elastic strain measured by the measuring means 35 is 140 με or less until the number of molded products produced is about 230. When the number of production exceeds approximately 230, the elastic strain measured by the measuring means 35 may exceed 140 με, and then the elastic strain measured by the measuring means 35 when the number of molded products produced is approximately 320. At this time, mold galling occurred in the convex portion 31 on the lower surface of the wrinkle presser mold 30.

In the case of the third embodiment, when the elastic strain measured by the measuring means 35 exceeds 140 με, for example, if the coating process such as plating of the convex portion 31 on the lower surface of the wrinkle presser mold 30 or application of a lubricant is appropriately performed. good. This makes it possible to repair the wrinkle presser mold 30 before the mold galling occurs.
In the third embodiment, two strain measuring means 35 are installed. However, even when only one strain measuring means 35 is installed, the galling of the measurement target mold can be detected in the same manner.

  The present invention can be applied to the field of press forming thin plates.

It is a schematic explanatory drawing of the press die apparatus concerning the 1st Embodiment of this invention. It is a perspective view of the container-shaped molded product press-molded by the press die apparatus concerning the 1st Embodiment of this invention. It is explanatory drawing of the crack which generate | occur | produces in the corner part in the recessed part of a punch lower surface. It is explanatory drawing of the stress concentration by the friction which generate | occur | produces in the shoulder part of die | dye. It is explanatory drawing of the attachment structure of a strain measurement means. It is a schematic explanatory drawing of the press die apparatus concerning the 2nd Embodiment of this invention. It is explanatory drawing of the stress concentration by the friction which generate | occur | produces in the inner corner | angular part of the convex part formed in the pad upper surface. It is a schematic explanatory drawing of the press die apparatus concerning the 3rd Embodiment of this invention. It is explanatory drawing of the stress concentration by the friction which generate | occur | produces on the lower surface of the convex part formed in the wrinkle pressing die lower surface. It is a graph which shows the relationship between the production number of the molded article in Example 1, and the elastic strain which generate | occur | produces in the corner part in the recessed part of a punch lower surface. It is a graph which shows the relationship between the elastic strain by the friction which generate | occur | produces in the shoulder part of die | dye, and the number of molded articles in Example 1. It is a graph which shows the relationship of the elastic strain by the friction which generate | occur | produces in the inner corner | angular part of the convex part formed in the pad upper surface and the production number in Example 2. FIG. It is a graph which shows the relationship between the elastic strain by the friction which generate | occur | produces on the lower surface of the convex part formed in the number of the molded articles in Example 3, and a wrinkle pressing die lower surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Punch 2 Die 2b Shoulder part 3 Convex part 3a Upper corner part 4 Convex part 4 Concave part 4a Corner part 5 Thin plate 6 Protrusion 7 Molded article 10 Crack 11, 12 Strain measuring means 20 Pad 21, 22 Convex part 22 Convex part 21a Inner corner 25 Strain measuring means 30 Wrinkle presser mold 31 Convex part 35 Strain measuring means

Claims (4)

A method of detecting an abnormality in a press mold apparatus, wherein at least one of the punch and the die is a measurement target mold when a thin plate is press-molded by relative movement of a punch and a die,
When the elastic strain generated in the measurement target mold in response to press molding, measured by a strain measuring means installed inside the measurement target mold, exceeds a predetermined range or falls below the predetermined range. An abnormality detection method for a thin plate press mold apparatus, characterized in that an abnormality of the measurement target mold is determined.   Furthermore, it has at least one or more of a pad and a crease presser mold interlocked with the punch, and at least one of the punch, the die, the pad and the crease presser mold is a measurement target mold. An abnormality detection method for a thin plate press die apparatus according to claim 1.   The abnormality detection method for a press mold apparatus for a thin plate according to claim 1 or 2, wherein a plurality of strain measuring means are installed inside the measurement target mold.   The abnormality detection method for a press die apparatus according to any one of claims 1 to 3, wherein the strain measuring means is a piezo element or a strain gauge.

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