Molding defect detection die

Abstract

To provide a molding defect detection die capable of easily detecting a defect.SOLUTION: There is provided a molding defect detection die, comprising: a manufacturing section that molds a product by injection molding; and a defect detection section that detects a defect in the product when the product is molded by injection molding.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] An embodiment of the present invention relates to a molding defect detection mold. [Background technology]

[0002] In injection molding, there is a technique for providing a sensor that detects the pressure behavior inside the cavity when the cavity is filled with molten raw material, and using the sensor to identify defective products due to insufficient raw material filling pressure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 63-92426 Summary of the Invention [Problem to be solved by the invention]

[0004] When a product is molded by filling a product section with raw material by injection molding, an engineer, a technician, or the like inspects the appearance of the product. Since inspection is thus dependent on an engineer, a technician, or the like, an operator needs a lot of experience to inspect whether or not there is a defect in the product and to appropriately change the parameters of the injection molding. In addition, since the type and location of defects differ depending on the product shape, it becomes necessary to perform inspection, for example, every time the product to be molded changes. Furthermore, there are problems with temperature, space, and the like when setting a sensor in the product section, and there are limitations.

[0005] An embodiment of the present invention provides a molding defect detection mold that can easily detect defects. [Means for solving the problem]

[0006] According to an embodiment, a molding defect detection mold includes a manufacturing unit that manufactures a product by injection molding, and a defect detection unit that detects defects in the product when the product is molded by injection molding. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram for explaining an example of an injection molding system according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view showing an example of a molding defect detection die according to the first embodiment. [Diagram 3] FIG. 3 is a perspective view showing an example of a fixing portion according to the first embodiment. [Figure 4] FIG. 2 is a perspective view showing an example of a movable portion of the first embodiment. [Diagram 5] FIG. 4 is a diagram showing an example of an arrangement of nested dies provided in the defect detection unit of the first embodiment. [Figure 6] FIG. 2 is a cross-sectional view showing an example of a nesting die for detecting a sink mark according to the first embodiment. [Figure 7] 4A to 4C are diagrams showing an example of an inspection result by the product inspection machine of the first embodiment. [Figure 8] FIG. 8 is an enlarged view of a portion of the image of the sink mark shown in FIG. 7 according to the first embodiment. [Figure 9] FIG. 3 is a cross-sectional view showing an example of a nesting die for detecting warpage according to the first embodiment. [Figure 10] FIG. 3 is a cross-sectional view showing an example of a nested die for detecting mold release in the first embodiment. [Figure 11] FIG. 2 is a perspective view showing an example of a nested die for detecting a filling defect in the first embodiment. [Figure 12] FIG. 2 is a perspective view showing an example of a nested die for detecting a weld line according to the first embodiment; [Figure 13] FIG. 4 is a view for explaining an example of a weld line in the first embodiment. [Figure 14] FIG. 4 is a view for explaining an example of a weld line in the first embodiment. [Figure 15] FIG. 4 is a perspective view showing an example of a nesting die for detecting optical performance defects in the first embodiment. [Figure 16] FIG. 13 is a diagram showing an example of an arrangement of nested dies provided in a defect detection unit according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios of each part may be different depending on the drawing. In this specification and each drawing, elements similar to those described above with reference to the previous drawings are given the same reference numerals and detailed descriptions thereof will be omitted as appropriate.

[0009] FIG. 1 is a diagram for explaining an example of an injection molding system 1. As shown in FIG. As shown in Fig. 1, the injection molding system 1 includes an injection molding machine 10, an adjusting machine 20, a product inspection machine 30, and a management device 40. The injection molding machine 10 includes a product molding section 15 including a base section 11, a heating cylinder 12, a resin injection section 13, a molding defect detection mold 100, and an extrusion mechanism 14. The injection molding machine 10 and the adjusting machine 20 are connected to be able to communicate with each other. The adjusting machine 20 and the management device 40 are connected to be able to communicate with each other. The product inspection machine 30 and the management device 40 are connected to be able to communicate with each other.

[0010] The injection molding machine 10 is a device for manufacturing a product by filling a mold with resin. The heating cylinder 12 is disposed on one end of the base 11, and the product molding section 15 is disposed on the other end. The product molding section 15 has a first wall 15a on the heating cylinder 12 side and a second wall 15b on the opposite side to the heating cylinder 12 side. A fixed part 110 of the molding defect detection mold 100 is attached to the first wall 15a. A movable part 150 of the molding defect detection mold 100 is attached to the second wall 15b. The base 11 has a step T in a side view. The height of the base 11 on the side where the heating cylinder 12 is disposed is higher than the height of the base 11 on the side where the product molding section 15 is disposed. The step T of the base 11 is configured to be movable, for example, toward the product molding section 15 side.

[0011] An operation panel 16 is provided on the heating cylinder 12 side of the product molding section 15. The operation panel 16 is connected to the management device 40 so as to be able to communicate with the management device 40. The operation panel 16 is provided with an operation screen 16a. An operator can operate the heating cylinder 12 or adjust parameters when the injection molding machine 10 performs injection molding by operating the operation panel 16 based on the display of the operation screen 16a. The parameters are, for example, the temperature, position, and pressure of the molding defect detection mold 100 during injection molding or the mold for the product. Information indicating the manufacturing state such as the temperature, position, pressure, manufacturing time, and type of resin when the product and / or the defective product is molded, and information indicating the ID of the product are transmitted to the management device 40. In addition, by operating the operation panel 16, information managed by the management device 40 can be displayed on the operation screen 16a. For example, condition information 40a described later can be displayed, and the operator can use the condition information 40a to set parameters.

[0012] The heating cylinder 12 is provided with a resin supplying section 13. The heating cylinder 12 is adapted to be in direct contact with the fixed section 110, and injects resin into the fixed section 110. The heating cylinder 12 has, for example, a single-shaft screw inside. By rotating the single-shaft screw, the heating cylinder 12 ejects the resin supplied from the resin supplying section 13 into the fixed section 110.

[0013] During injection molding, the step T of the base 11 moves from the position on the right side of the base 11 shown in FIG. 1 to the fixed part 110 of the molding defect detection mold 100. The movable part 150 moves from the second wall 15b to the first wall 15a. This causes the movable part 150 to abut against the fixed part 110. In this state, when the resin discharged from the tip of the heating cylinder 12 fills the molding defect detection mold 100, in this embodiment, the injection molding machine 10 can simultaneously mold the product and the defective detection product using the molding defect detection mold 100. If a mold for normal products is used, the injection molding machine 10 can mold only the product. Details of the molding defect detection mold 100 will be described later.

[0014] After the injection molding is completed and the molding defect detection mold 100 is filled with resin, the molding defect detection mold 100 is cooled to harden the resin, and then the movable part 150 moves from the first wall 15a side to the second wall 15b side. This creates a distance between the fixed part 110 and the movable part 150. If there is a product on the movable part 150, the product and the detected defect product can be pushed out and removed by the push-out mechanism 14.

[0015] The regulator 20 regulates the temperature of the product mold or the molding defect detection mold 100 according to the settings made on the operation panel 16 .

[0016] The product inspection machine 30 inspects the shapes of products and defective products, etc. As indicated by arrow A1, the products and defective products are transported from the injection molding machine 10 to the product inspection machine 30 automatically by a predetermined transport device or manually by an operator.

[0017] The product inspection machine 30 is, for example, a laser displacement meter or an image inspection device. In the case of a laser displacement meter, the product inspection machine 30 measures the shape of the product and / or the detected defective product, and judges whether the measured shape meets the specified conditions. In the case of an image inspection device, the product inspection machine 30 takes an image of the product, and judges whether the product and / or the detected defective product meets the specified conditions based on the taken image. Information indicating the inspection results of the product and / or the detected defective product is transmitted to the management device 40 together with information indicating the ID of the product. In this embodiment, a case will be described in which information indicating the inspection results is transmitted from the product inspection machine 30 to the management device 40, but the inspection may be performed manually by an inspector's visual inspection, etc., and the operator may input the inspection results to the management device 40.

[0018] The management device 40 is an information processing device such as a personal computer. It is capable of inputting and managing information. In this embodiment, the management device 40 manages condition information 40a, product information 40b, correspondence relationship information 40c, and detected defective product information 40d.

[0019] The condition information 40a is information indicating, for example, the temperature, screw position, injection pressure, injection speed, filling time, and mold number during injection molding for each product. The product information 40b is information indicating, for example, the temperature, screw position, injection pressure, injection speed, filling time, production time, type of resin, mold number, and inspection result during injection molding for each product ID. The product information 40b is acquired from the operation panel 16. The correspondence information 40c is information indicating, for example, a correspondence that allows a product to be determined to be a good product even if a defect is detected in a defective detected product. The defective detected product information 40d is information indicating, for example, the temperature, screw position, injection pressure, injection speed, filling time, production time, type of resin, mold number, and inspection result during injection molding to mold the defective detected product. Note that the information managed by the management device 40 is not limited to these.

[0020] Next, the molding defect detection die 100 will be described. Fig. 2 is a perspective view showing an example of the molding defect detection die 100. Fig. 3 is a perspective view showing an example of a fixed part 110 of the molding defect detection die 100. Fig. 4 is a perspective view showing an example of a movable part 150 of the molding defect detection die 100.

[0021] As shown in Fig. 2, the molding defect detection die 100 is used during injection molding, with a fixed part 110 and a movable part 150 integrated together. As shown in Fig. 3 and Fig. 4, the molding defect detection die 100 includes a product recess 120a and a product protrusion 120b (product part) for manufacturing a product by injection molding, and a defect detection part 130 for detecting defects in the product when the product is molded by injection molding.

[0022] As shown in FIG. 2 and FIG. 3, the fixing part 110 includes a plate-shaped first mounting plate 111 and a rectangular parallelepiped first mold plate 112 that is one size smaller than the first mounting plate 111. The first mounting plate 111 is attached to the first wall 15a, and the fixing part 110 is attached inside the product molding part 15. The first mounting plate 111 has circular holes 113 at four corners, and the first mold plate 112 has circular holes 114 at four corners. In this embodiment, the first mold plate 112 is provided with a product recess 120a and a defect detection part 130. The product recess 120a has a first product recess 121a and a second product recess 122a. The first product recess 121a, the second product recess 122a, and the defect detection part 130 are connected to each other via a groove M.

[0023] As shown in Figs. 2 and 4, the movable part 150 has a plate-shaped second mounting plate 151, a spacer 152, and a rectangular parallelepiped second mold plate 153 that is one size smaller than the second mounting plate 151. The spacer 152 is provided between the second mold plate 153 and the second mounting plate 151. The second mounting plate 151 is attached to the second wall 15b, and the movable part 150 is movably attached inside the product molding section 15. The second mold plate 153 has cylindrical parts 154 at the four corners. In this embodiment, the second mold plate 153 is provided with a product protrusion 120b. The product protrusion 120b has a first product protrusion 121b and a second product protrusion 122b.

[0024] As shown in FIG. 2, when the fixed part 110 and the movable part 150 are arranged to face each other, the first product recess 121a and the first product protrusion 121b, and the second product recess 122a and the second product protrusion 122b are arranged to face each other. In addition, the four cylindrical parts 154 of the movable part 150 are inserted into the four holes 114 of the fixed part 110. At this time, gaps are provided between the first product recess 121a and the first product protrusion 121b, and between the second product recess 122a and the second product protrusion 122b. The resin supplied from the heating cylinder 12 is filled into this gap. The resin is also filled into the defect detection part 130 through the groove M. This makes it possible for the molding defect detection mold 100 to mold a product and a defect detection product at the same time.

[0025] Next, a description will be given of the defect detection section 130. In this embodiment, the defect detection section 130 is provided in the fixed section 110 as shown in FIG.

[0026] Fig. 5 is a diagram showing an example of the arrangement of a nested mold 200 provided in the defect detection unit 130. As shown in Fig. 5, the nested mold 200 is arranged in the defect detection unit 130. The nested mold 200 is connectable to a groove M, and resin is filled from the groove M to mold a detected defect product.

[0027] In this embodiment, the nesting die 200 is replaceably arranged in the defect detection unit 130. There are a plurality of types of nesting die 200, and these plurality of types of nesting die 200 are used to detect different types of defects in products, respectively. In other words, by replacing the nesting die 200 arranged in the defect detection unit 130, the molding defect detection die 100 becomes able to detect a plurality of types of defects.

[0028] In this embodiment, for example, the shape of the nesting die 200 is formed so as to facilitate detection of defects in the product to be molded. For example, the nesting die 200 is based on the dimensions of the shape of the product or a shape obtained by reducing the dimensions of the shape of the product, and this base shape is further deformed so as to facilitate detection of defects in the product. The shape of the nesting die 200 and the manner of deformation vary depending on the type of defect to be detected.

[0029] In this embodiment, defects of the product to be detected are sink marks, warpage, mold release, filling defects, weld lines, and refractive index distribution, but the defects to be detected are not limited to these. Six types of nesting dies 200, specifically, nesting dies 210, 220, 230, 240, 250, and 260 described below, are provided so that each defect can be detected. It is not essential to detect all defects, namely sink marks, warpage, mold release, weld lines, and refractive index distribution, and it is sufficient to detect at least one of the defects.

[0030] First, a case where the defect detection target is a sink mark will be described. In this embodiment, the sink defect is a phenomenon that occurs due to the shrinkage of resin, and refers to a defect in which a dent occurs on the surface of a product.

[0031] FIG. 6 is a cross-sectional view showing an example of a nested die 210 for detecting a sink defect. As shown in Fig. 6, the shape of the nesting die 210 has a ribbed structure having a root portion 211 and a protrusion 212. A defective product 213 is molded inside the nesting die 210. In a product with a ribbed structure, a sink mark 213a is likely to occur on the lower surface of the root portion 211 where the protrusion 212 is provided. For this reason, the closer the root dimension L0 of the root portion 211 of the nesting die 210 is to the basic wall thickness dimension L1 of the product, the more likely sink marks will occur and the easier it will be to detect defects. The relationship between L1 and L0 is basically L1>L0.

[0032] The nesting die 210 is based on the basic wall thickness dimension L1 of the product actually formed by the product recess 120a and the product protrusion 120b, but the dimension of the root portion 211 is set to be equal to or smaller than the basic wall thickness dimension. In this embodiment, for example, the dimension of the root portion 211 is set to be 40% to 60% of the basic wall thickness dimension. More specifically, when the product formed by the product recess 120a and the product protrusion 120b is, for example, a mechanical part that does not require quality accuracy in appearance or a general part, the dimension L0 of the root portion 211 is set to be about 40% to 50% of the basic wall thickness dimension. Also, when the product is, for example, an appearance part with high quality accuracy, the dimension L0 of the root portion 211 is set to be about 50% to 60% of the basic wall thickness dimension. In this way, the nesting die 210 may change the detection accuracy of sink marks depending on the type of product.

[0033] In addition, the relationship between the recess dimensions and external shape of the defective detected product 213 formed by the nesting die 210 and the dimensions and external shape of the product formed by the product recess 120a and the product protrusion 120b is obtained in advance. After the relationship is obtained in advance, the range of the sink of the defective detected product 213 when the product is a non-defective product is specified, and a correspondence relationship is obtained for determining the product as a non-defective product even if a sink defect is detected. For example, even if a sink mark 213a occurs in the defective detected product 213, if the inspection result by the product inspection machine 30 shows that the recess dimensions of the sink mark 213a are 0.01 mm or more and 0.03 mm or less, the product inspection machine 30 determines that the product is a non-defective product even if a sink defect is detected. A correspondence relationship is obtained in advance that corresponds the sink defect of the defective detected product and whether the product is a non-defective product or not. This correspondence relationship is stored in the management device 40 as correspondence relationship information 40c. If the recess dimension of the sink mark 213a exceeds the above range, the product inspection machine 30 judges the product to be defective.

[0034] FIG. 7 is a diagram showing an example of an inspection result by the product inspection machine 30. In this embodiment, the product inspection machine 30 judges the state of the sink mark 213a by image inspection. FIG. 7 shows an image IM of the sink mark 213a. FIG. 8 shows an enlarged image IM1 of a part of the image IM shown in FIG. 7. As shown in FIG. 8, the product inspection machine 30 measures the pitch deviations P1, P2, P3, and P4 of the sink mark 231a from the enlarged image IM1 of the sink mark, quantifies the amount of unevenness, and measures the surface shape SL. From this surface shape SL, the product inspection machine 30 can calculate the recess dimension of the sink mark 231a.

[0035] When the image inspection shows that the dent dimension of the sink mark of the defective product 213 exceeds the above range (0.01 mm or more and 0.03 mm or less), the product inspection machine 30 judges the product to be defective. For this reason, the product inspection machine 30 transmits information indicating the defective product, the temperature, screw position, injection pressure, injection speed, filling time, manufacturing time, type of resin, type of mold, etc., during injection molding of the product, and the product ID to the management device 40. The information is managed as defective product information 40d in the management device 40. The management device 40 can feed back the defective product information 40d to the condition information 40a for performing injection molding of the product. This allows the optimization of parameters during injection molding of the injection molding machine 10. The management device 40 can also utilize the defective product information 40d to notify the maintenance time of the molding defect detection mold 100.

[0036] Next, a case where the defect detection target is warpage will be described. In this embodiment, the warpage defect refers to a defect in which deformation occurs in a product after the cooled product is removed from the mold.

[0037] FIG. 9 is a cross-sectional view showing an example of a nested die 220 for detecting warpage defects. 9, the shape of the nesting mold 220 is box-shaped. In a box-shaped product, the amount of warpage changes depending on the conditions during injection molding, such as temperature, screw position, injection pressure, injection speed, filling time, manufacturing time, type of resin, type of mold, etc. Based on the amount of change in the amount of warpage, the defect of warpage 221a of the defective detection product 221 is detected.

[0038] The nesting die 220 is based on the basic dimensions of the product actually formed by the product recess 120a and the product protrusion 120b, but in this embodiment, it is set to 30% to 70% of the basic dimensions of the product (vertical dimension L2, horizontal dimension L3, depth). If there is a portion where warping occurs significantly, the dimensions of the nesting die 220 of that portion may be made the same as the shape of that portion of the product. In addition, the ratio of the vertical dimension L2 and / or the horizontal dimension L3 may be changed to improve the detection accuracy of the warping of the product. For example, in the case of the nesting die 220 shown in FIG. 9, the horizontal dimension L3 can be made longer than the vertical dimension L2 to increase the warping 221a. By making such a change, it is possible to improve the detection accuracy of the warping 221a.

[0039] The product inspection machine 30 measures the outer shape of the defective detected product 221 using, for example, a laser displacement meter, and detects the warp 221a of the defective detected product 221 based on the measurement result, and judges whether the product is a good product or not. A correspondence relationship is determined in advance such that even if the defective detected product 221 has a warp 221a, the product is a good product if the vertical warp dimension of the defective detected product 221 is 0.1 mm or more and 0.3 mm or less. The management device 40 stores such a correspondence relationship as correspondence relationship information 40c, and can use it to optimize the condition information 40a and notify the maintenance timing of the molding defect detection mold 100 based on the defective detected product information 40d, just like the sink defect case described above.

[0040] Next, a case where the object of defect detection is mold release will be described. In this embodiment, the mold release failure refers to the state of mold release when the resin is removed after solidifying in the molding defect detection mold 100. The state of mold release is related to the adhesion between the resin material and the molding defect detection mold 100, the friction coefficient, the molding shrinkage rate, the rigidity of the material, and the like.

[0041] FIG. 10 is a cross-sectional view showing an example of a nested die 230 for detecting a demolding failure. As shown in FIG. 10, the shape of the insert die 230 is a box shape with a trapezoidal cross section. A defective product 231 is molded inside the nesting mold 230. The state of release from the mold changes depending on the angle α between the oblique side of the trapezoid of the nesting mold 230 and a line L4 perpendicular to the parting line PL. The angle α indicates the draft angle when the nesting mold 230 is removed from the defective product 231. Based on the state of release of the defective product 231 from the nesting mold 230, the product inspection machine 30 detects a release failure.

[0042] The nesting die 230 is based on the basic dimensions of the product actually formed by the product recess 120a and the product protrusion 120b, but in this embodiment, it is set to 30% to 70% of the basic dimensions of the product. Furthermore, it is based on the smallest draft angle of the actual product, but the draft angle of the nesting die 230 is made smaller than the draft angle of the product. For example, if the draft angle of the product is 3 degrees, the draft angle of the nesting die 230 is set to 2.7 degrees, which is about 10% smaller than the 3 degrees.

[0043] In this embodiment, the mold release inspection is performed simultaneously with mold opening because the fixed part 110 is provided with the defect detection part 130. The degree of deformation of the defective detection product 231 when the mold is opened is inspected by the product inspection machine 30. If the deformation worsens, a part of the defective detection product 231 may remain in the nesting mold 230. The product inspection machine 30 may use, for example, a laser displacement meter. In addition, even if the defective detection product 231 is deformed, if the deformation value is within a certain range, a correspondence relationship is obtained in advance that indicates that the product is a non-defective product. The management device 40 stores such a correspondence relationship as the correspondence relationship information 40c, and the management device 40 can use the correspondence relationship to optimize the condition information 40a and to notify the maintenance time of the molding defect detection mold 100 based on the defective detection product information 40d, as in the case of the sink defect described above.

[0044] When the movable part 150 is provided with the defect detection part 130, the defective product 231 can be removed from the nesting die 230 by pushing it out with the push-out mechanism 14. Therefore, the product inspection machine 30 may measure the pushing force of the push-out mechanism 14 to obtain the inspection result of the release state and inspect the demolding property.

[0045] Next, a case where the object of defect detection is a filling defect, that is, an unfilled defect or an overfilled (burr) defect will be described. In this embodiment, an unfilled defect refers to a state in which resin is not filled into a specific portion in the product part. An overfilled defect refers to a state in which the injection pressure is high and more resin is filled into the product part than necessary.

[0046] FIG. 11 is a perspective view showing an example of a nested mold 240 for detecting a filling defect. As shown in Fig. 11, the nested mold 240 includes a gate 241, an underfill detection portion 242, and an overfill detection portion 243. The nested mold 240 does not have to include the overfill detection portion 243. Fig. 11 shows a state in which the gate 241, the underfill detection portion 242, and the overfill detection portion 243 are filled with resin, and a defective detected product 244 is formed.

[0047] In the gate 241, the resin filled from the groove M is filled into the unfilled detection section 242. In this embodiment, the unfilled detection section 242 is box-shaped and detects whether or not the resin for molding the product has been filled. The unfilled detection section 242 has a plurality of V-grooves on the upper surface. The plurality of V-grooves are arranged at equal intervals in a direction perpendicular to the direction A2 in which the resin is filled from the gate 241. In FIG. 11, a line formed by the plurality of V-grooves 242a is formed on the detected defective product 244. The overfilled detection section 243 detects that an excess of resin is being supplied to the product due to the resin being filled from the unfilled detection section 242.

[0048] The unfilled detection portion 242 of the nesting mold 240 is based on the basic dimensions of the product actually formed by the product recess 120a and the product protrusion 120b, but in this embodiment, it is set to 30% to 70% of the basic dimensions of the product. If there is a portion where unfilling is noticeable, the dimensions of the unfilled detection portion 242 of that portion may be set to the same dimensions as the shape of that portion of the product.

[0049] The product inspection machine 30 performs an inspection on, for example, the defective product 244 removed from the nesting mold 240. The amount of resin filled can be determined by the product inspection machine 30 acquiring the number of lines formed by the multiple V-grooves 242a on the upper surface of the defective product 244. The product inspection machine 30 can acquire the number of lines on the upper surface of the defective product 244, for example, by image inspection. For example, it is determined in advance that the line from the third V-groove 242a from the gate 241 side to the line from the sixth V-groove 242a is within an appropriate range in which the filling property of the product can be ensured. If the number of acquired lines is three or less counted from the gate 241 side, the product inspection machine 30 determines that a non-filling defect in which the filling property of the product cannot be ensured has occurred. Also, if the number is seven or more, it is considered that the flow length of the filled resin has become longer. Therefore, the product inspection machine 30 can determine that the viscosity of the resin has decreased and the temperature of the resin has changed. In this case, it is determined that there is a possibility that other defects have occurred, such as a large variation in the resin lot.

[0050] Furthermore, when the product inspection machine 30 acquires, for example, by image inspection, that the overfill detection unit 243 is filled with resin, it can determine the possibility that burrs have occurred on the product.

[0051] When the product inspection machine 30 determines that a filling defect occurs in the detected defective product, the detected defective product information 40d is transmitted to the management device 40. Based on the detected defective product information 40d, the management device 40 can use it to optimize the condition information 40a and to notify the maintenance timing of the molding defect detection mold 100, similarly to the sink mark case described above.

[0052] Although the case where multiple V-shaped grooves 242a are provided on the upper surface of the non-filling detection portion 242 has been described, multiple V-shaped grooves 242a may be provided on the lower surface. Also, any groove that can form a line in the non-filling detection portion 242 may be used instead of the V-shaped groove 242a.

[0053] Next, a case where the defect detection target is a weld line will be described. In this embodiment, the weld line defect refers to a defect caused by a phenomenon of insufficient fusion occurring at a point where resins join together.

[0054] FIG. 12 is a perspective view showing an example of a nested mold 250 for detecting a weld line. As shown in Fig. 12, the nested mold 250 includes a first gate 251, a second gate 252, and a weld line detection portion 253. The weld line detection portion 253 is plate-shaped. Fig. 12 shows a state in which the first gate 251, the second gate 252, and the weld line detection portion 253 are filled with resin, and a defective product 254 is formed.

[0055] 12, the resin is filled from the groove M into the weld line detection section 253 through the first gate 251 and the second gate 252. In the weld line detection section 253, the resin filled from the first gate 251 and the resin filled from the second gate 252 join together to fill the weld line detection section 253.

[0056] The dimensions of the product actually molded by the product recess 120a and the product protrusion 120b are the basic dimensions of the nesting die 250. If there is a portion where a weld line is likely to occur, the shape of the nesting die 250 in that portion may be made to be a shape where a weld line is likely to occur.

[0057] 13 and 14 are diagrams for explaining an example of a weld line. Fig. 14 shows the weld line after some time has passed since the state of Fig. 13.

[0058] As shown in FIG. 13, resin 251a flows in the direction of arrow A3 (to the right in the figure) from first gate 251. Resin 252a flows in the direction of arrow A4 (to the left in the figure) from second gate 252. A weld line W1 is formed between this resin 251a and resin 252a. The meeting angle formed between the tip of this resin 251a and the tip of resin 252a is angle Θ1. Angle Θ1 is, for example, about 30 degrees. The weld line W1 occurs up to the vicinity of the tip of the meeting angle.

[0059] When the meeting angle exceeds 90 degrees, the molecular directions in the resin 251a and the resin 252a are almost the same. This prevents the weld line from occurring. As shown in FIG. 14, the meeting angle is angle Θ2. The angle Θ2 is, for example, about 120 degrees. Therefore, the weld line W2 ends at a position farther away from the tip of the meeting angle than the weld line W1 shown in FIG. 13.

[0060] The product inspection machine 30 measures the length of the weld line by, for example, image inspection, and judges whether the product is a good product or not. For example, even if a weld line occurs in the defective detected product 254, if the measured length of the weld line is 3 mm or less, a correspondence relationship is obtained in advance that determines that the product is a good product. If the length of the weld line W1 exceeds 3 mm, it can be determined that the viscosity of the resin during injection molding, the resin temperature, or the temperature of the molding defect detection mold 100, the injection speed, etc. have changed. If it is determined to be defective, information on this judgment result is sent to the management device 40 as defective detected product information 40d.

[0061] The management device 40 stores such correspondence as correspondence information 40c, and the management device 40 can utilize the correspondence to optimize the condition information 40a and notify the maintenance timing of the molding defect detection mold 100 based on the defective detected product information 40d, just like in the case of sink defects described above.

[0062] Next, a case where the defect detection is performed on optical performance will be described. In this embodiment, poor optical performance refers to a defect in which the distribution of the refractive index of light is not within a specified range.

[0063] 15 is a perspective view showing an example of a nesting mold 260 for detecting poor optical performance. Note that the products actually produced are transparent parts such as optical components, which are parts that require optical performance.

[0064] As shown in Fig. 15, the nesting die 260 has a cylindrical shape. The shape of the nesting die 260 does not depend on the product shape, and the diameter D11 is 5 mm or more and 10 mm or less, and the length L11 is 30 mm or more and 50 mm or less. In Fig. 15, a defective product 261 is molded in the nesting die 260.

[0065] The product inspection machine 30 measures the refractive index distribution of the defective detected product 261 molded by the nesting mold 260, for example, using the background-oriented Schlieren method (BOS). The relationship between the optical characteristics of the product and the refractive index distribution is obtained, and a correspondence relationship is obtained that allows the defective detected product 261 to be determined as a good product even if its refractive index distribution is defective. The product inspection machine 30 stores the refractive index distribution of a good product as a numerical value or an image, for example, and compares it with the refractive index distribution of the defective detected product 261 to determine whether the product is good or not. If it is determined to be defective, this determination result is transmitted to the management device 40 as defective detected product information 40d.

[0066] The management device 40 stores the above-mentioned correspondence as correspondence information 40c, and the management device 40 can use the correspondence information 40d to optimize the condition information 40a and to notify the maintenance timing of the molding defect detection mold 100, just like in the case of sink defects described above.

[0067] As described above, by replacing the nesting dies 210, 220, 230, 240, 250, and 260 in the defect detection section 130 of the molding defect detection die 100, multiple types of defects in the product can be easily detected.

[0068] Second embodiment In the second embodiment, the defect detection unit is configured to be able to accommodate a plurality of nesting dies. This is different from the first embodiment in that a plurality of types of nesting dies 200 are accommodated in the defect detection unit 130, so that a plurality of types of defects can be detected.

[0069] Fig. 16 is a diagram showing an example of the arrangement of the nesting dies 210, 220 provided in the defect detection unit 130. As shown in Fig. 16, the nesting die 210 is connected so that it can be filled with resin from the groove M. Furthermore, the nesting die 220 is connected so that it can be filled with resin from the nesting die 210. In other words, the nesting dies 210 and the nesting die 220 are connected from the groove M. With this configuration, the molding defect detection die 100 can detect sink defects of the nesting die 210 as well as warp defects of the nesting die 220 at the same time.

[0070] 16, the nesting die 230 may be connected so as to be able to be filled with resin from the groove M, and the nesting die 240 may be connected so as to be able to be filled with resin from the nesting die 230. When configured in this way, the molding defect detection die 100 can further simultaneously detect demolding defects and filling defects.

[0071] According to the molding defect detection die 100 of the second embodiment, any number of types of defects can be detected simultaneously.

[0072] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. In addition, the above-mentioned embodiments can be implemented in combination with each other.

[0073] The embodiments include the following aspects.

[0074] (Appendix 1) A manufacturing department that molds products by injection molding; a defect detection unit that detects defects in the product when the product is molded by the injection molding; A molding defect detection mold equipped with the above-mentioned.

[0075] (Appendix 2) The defect detection unit is configured to accommodate a nesting die in an exchangeable manner, There are multiple types of the nesting mold, The plurality of types of nesting dies are used to detect different types of defects of the product, respectively. A molding defect detection mold as described in Appendix 1.

[0076] (Appendix 3) The defect detection unit is configured to be able to accommodate a plurality of the nesting dies, The plurality of nested dies accommodated are each used for detecting a different type of defect. A molding defect detection mold as described in Appendix 1. [Explanation of symbols]

[0077] 100... molding defect detection mold, 110... fixed part, 120a... product concave part, 120b... product convex part, 130... defect detection part, 150... movable part, 200... nested mold, 210, 220, 230, 240, 250, 260... nested mold

Claims

1. A manufacturing department that molds products by injection molding; a defect detection unit that detects defects in the product when the product is molded by the injection molding; A molding defect detection mold equipped with the above.

2. The defect detection unit is configured to accommodate a nesting die in an exchangeable manner, There are multiple types of the nesting mold, The plurality of types of nesting dies are used to detect different types of defects of the product, respectively. The molding defect detection mold according to claim 1.

3. The defect detection unit is configured to be able to accommodate a plurality of the nesting dies, The plurality of nested dies accommodated are each used for detecting a different type of defect. The molding defect detection mold according to claim 1.

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