Inspection device, injection molding system, inspection method

Abstract

To provide an inspection apparatus or the like capable of highly accurately determining whether or not a molded article is molded normally.SOLUTION: An inspection apparatus includes: a linear polarizer 112 and a wave plate 113 generating polarized light from light emitted from a light source 111; a polarization camera 114 imaging the polarized light generated by the linear polarizer 112 and the wave plate 113 and transmitted through a molded article 3; and a determination unit determining a state of the molded article by using an image captured by the polarization camera 114.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an inspection apparatus, an injection molding system, and an inspection method.

Background Art

[0002] For example, Patent Document 1 describes an injection molding machine including a cylinder for heating a resin filled in a mold device and a monitor device for monitoring the situation in the cylinder based on the ratio of the refractive index of a molded product formed of the resin to a reference refractive index set according to the type of the resin. Further, Patent Document 2 describes a molding condition setting value correction device used for an injection molding machine that controls an injection molding process based on set values, including a light source for irradiating an injection molded product through a polarizing plate, an imaging means for imaging the injection molded product through the polarizing plate, and a setting value correction means for correcting the set values based on a polarization fringe pattern obtained by the imaging means.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Against the background of corporate competitiveness expansion and voluntary efforts related to volatile organic compound (VOC) emissions reduction, etc., resin molding apparatuses are increasingly required to be equipped with an autonomous molding mechanism that can autonomously determine molding parameters. In order to autonomously determine molding parameters to realize an autonomous molding mechanism, it is desirable to accurately determine whether a molded product is normally molded. An object of the present invention is to provide an inspection apparatus or the like that can accurately determine whether a molded product is normally molded.

Means for Solving the Problem

[0005] The present invention completed under such an object is an inspection apparatus including: a generation means for generating polarized light from light emitted from a light source; a polarization camera for imaging light transmitted through a molded product from the polarized light generated by the generation means; and a determination unit for determining the state of the molded product using an image captured by the polarization camera.

Advantages of the Invention

[0006] According to the present invention, it is possible to accurately determine whether a molded product is normally molded or not.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. <First Embodiment> FIG. 1 is a diagram showing an example of the schematic configuration of an injection molding system 1 according to the first embodiment. FIG. 2 is an example of a block diagram showing the functions of the control device 40 and the processing device 120. The injection molding system 1 includes an injection molding machine 2 and an inspection device 100 that inspects whether or not a molded product 3 (see FIG. 3) molded by the injection molding machine 2 is properly molded.

[0009] <<Injection Molding Machine 2>> First, the injection molding machine 2 will be described. In the following description, the resin injection direction is defined as the front side, and the direction opposite to the resin injection direction is defined as the rear side. The injection molding machine 2 includes a mold clamping device (not shown), an injection device 10, a material supply device 81, a control device 40 that controls the entire device, an operation unit 51 that receives input operations from the user, and a display unit 52 that displays an operation reception screen and images.

[0010] The mold clamping device, the injection device 10, the material supply device 81, and the control device 40 will be described in detail later. The operation unit 51 can be exemplified by an input device such as a button, a switch, or a touch panel. The display unit 52 can be exemplified by a liquid crystal display or an organic EL display. The operation unit 51 and the display unit 52 may be integrally configured.

[0011] The injection molding machine 2 repeats the production of the molded product 3 with one cycle consisting of a mold closing process, a mold clamping process, a filling process, a pressure holding process, a cooling process, a metering process, a mold opening process, and an ejection process. The mold closing process is a process of closing the mold device composed of a fixed mold and a movable mold. The mold clamping process is a process of clamping the mold device. The filling process is a process of pouring molten resin into the mold device. The pressure holding process is a process of applying pressure to the poured resin. The cooling process is a process of solidifying the resin in the mold device after the pressure holding process. The metering process is a process of metering the molten resin for the next molded product 3. The mold opening process is a process of opening the mold device. The ejection process is a process of ejecting the molded product 3 from the mold device after the mold opening. Note that for shortening the molding cycle, the metering process may be performed while the cooling process is being carried out.

[0012] (Mold clamping device) The mold clamping device includes a fixed platen to which the fixed mold is attached and a movable platen to which the movable mold is attached, and performs mold closing, mold clamping, and mold opening by advancing and retracting the movable platen to bring the movable mold into contact with and away from the fixed mold. The type of the mold clamping device is not particularly limited. For example, it can be exemplified by a toggle type using an electric motor and a toggle mechanism, a direct pressure type using a fluid pressure cylinder, and an electromagnetic type using a linear motor and an electromagnet.

[0013] (Injection device 10) The injection device 10 has a cylinder 11 for heating the resin as a molding material and a nozzle 12 disposed at the front end of the cylinder 11. Further, the injection device 10 has a screw 20 rotatable and axially movable in the cylinder 11, heaters h11, h12, and h13 as heating sources for heating the cylinder 11, and a drive device 60 disposed at the rear side of the cylinder 11.

[0014] The screw 20 has a screw body 21 and an injection part 22 disposed on the front side of the screw body 21, and is connected to the drive device 60 via a shaft part at the rear end. The screw body 21 has a flight part 23 and a pressure member 24 detachably disposed with respect to the front end of the flight part 23. The flight part 23 has a rod-shaped main body part 23a and a spiral flight 23b formed so as to protrude from the outer peripheral surface of the main body part 23a, and a spiral thread groove 26 is formed along the flight 23b. From the rear end to the front end of the flight part 23, the depth of the thread groove 26 is constant, and it can be exemplified that the screw compression ratio is constant.

[0015] Note that the screw 20 may be formed with the flight part 23 over the entire screw body 21 without having the pressure member 24. Further, the screw body 21 may be distinguished into a supply part to which resin is supplied, a compression part that melts the supplied resin while compressing it, and a metering part that measures the melted resin in a fixed amount from the rear end to the front end. It is preferable that the depth of the thread groove 26 is deepest at the supply part, shallowest at the metering part, and becomes shallower from the rear side to the front side in the compression part.

[0016] The injection part 22 has a head part 31 having a conical part at the tip, a rod part 32 formed adjacent to the rear side of the head part 31, a check ring 33 disposed around the rod part 32, and a seal ring 34 attached to the front end of the pressure member 24. During the metering process, as the screw 20 retreats, when the check ring 33 is moved forward with respect to the rod part 32 and separated from the seal ring 34, the resin is sent from the rear side to the front side of the injection part 22. Further, during the injection process, as the screw 20 advances, when the check ring 33 is moved rearward with respect to the rod part 32 and brought into contact with the seal ring 34, the backflow of the resin is prevented.

[0017] At the rear part of the cylinder 11, a resin supply port 14 as a molding material supply port is formed. The resin supply port 14 is formed at a position facing the rear end portion of the thread groove 26 in a state where the screw 20 is positioned at the foremost side within the cylinder 11. A material supply device 81 for supplying resin into the cylinder 11 is attached to the resin supply port 14.

[0018] The drive device 60 is a device for rotating and advancing / retreating the screw 20 within the cylinder 11. The drive device 60 includes a metering motor 61 as a drive source for rotating the screw 20 within the cylinder 11, and an injection motor 71 as a drive source for moving the screw 20 in the rotational axis direction within the cylinder 11. It can be exemplified that the metering motor 61 and the injection motor 71 are servo motors.

[0019] Between the injection motor 71 and the screw 20, a motion conversion mechanism or the like for converting the rotational motion of the injection motor 71 into the linear motion of the screw 20 is provided. For example, the motion conversion mechanism has a screw shaft and a screw nut screwed onto the screw shaft. It can be exemplified that balls, rollers, or the like are provided between the screw shaft and the screw nut. The drive source for moving the screw 20 in the rotational axis direction is not limited to the injection motor 71, and for example, a hydraulic cylinder or the like may be used.

[0020] (Material supply device 81) The material supply device 81 includes a hopper 82 for accommodating a molding material (for example, resin pellets), a feed cylinder 83 extending horizontally from the lower end of the hopper 82, and a cylindrical guide portion 84 extending downward from the front end of the feed cylinder 83. Further, the material supply device 81 includes a feed screw 85 rotatably disposed within the feed cylinder 83, and a feed motor 86 for rotating the feed screw 85.

[0021] The resin supplied from the hopper 82 into the feed cylinder 83 is advanced along the screw groove of the feed screw 85 as the feed screw 85 rotates. The resin sent from the front end of the feed screw 85 into the guide part 84 drops within the guide part 84 and is supplied into the cylinder 11.

[0022] Note that the feed cylinder 83 does not necessarily have to extend in the horizontal direction, and for example, it may extend obliquely with respect to the horizontal direction. Also, the outlet side of the feed cylinder 83 may be higher than the inlet side. Also, the resin supplied into the feed cylinder 83 may be heated by a heater (not shown). At this time, it is preferable that the resin is heated to a temperature at which it does not melt, for example, a predetermined temperature below the glass transition point.

[0023] (Control device 40) The control device 40 includes a CPU 41, a ROM 42 that stores a control program and the like, a readable / writable RAM 43 that stores calculation results and the like, a storage unit 44 such as a hard disk, an input interface (I / F) 45, and an output interface (I / F) 46. The control device 40 realizes various functions by causing the CPU 41 to execute a program stored in the ROM 42 or the storage unit 44 or the like.

[0024] The control device 40 has a motor control unit 47 that controls the driving of motors such as the metering motor 61, the injection motor 71, and the feed motor 86, a heater control unit 48 that controls the temperatures of the heaters h11 to h13, and a parameter correction unit 49 that corrects the molding parameters when molding the molded product 3. The functions of the motor control unit 47 and the heater control unit 48 will be described in association with the operation of the injection molding machine 2 described below. The parameter correction unit 49 will be described in detail later.

[0025] (Operation of the injection molding machine 2) The operation of the injection molding machine 2 controlled by the control device 40 will be described below. In the metering process, the motor control unit 47 of the control device 40 drives the metering motor 61 to rotate the screw 20. At this time, the motor control unit 47 drives the feed motor 86 to rotate the feed screw 85. The motor control unit 47 can exemplify rotating the screw 20 and the feed screw 85 synchronously during molding. The motor control unit 47 controls the current supplied to the metering motor 61 so that the rotation speed of the screw 20 becomes, for example, the rotation speed set via the operation unit 51. Further, the motor control unit 47 controls the current supplied to the feed motor 86 so that the rotation speed of the feed screw 85 becomes, for example, the rotation speed set via the operation unit 51.

[0026] The resin supplied into the cylinder 11 by the material supply device 81 is immediately sent forward by the screw 20 without staying at the resin supply port 14. The resin is not densely filled in the screw groove 26 of the screw 20, and the state of the resin in the screw groove 26 is a sparse state. Therefore, the faster the resin supply speed by the material supply device 81, the more the amount of resin sent forward per unit time by the screw 20 increases.

[0027] The resin supplied into the cylinder 11 is advanced along the screw groove 26 of the screw 20 as the screw 20 rotates, and is heated and melted by the heaters h11 to h13. The heater control unit 48 of the control device 40 controls the power supplied to the heaters h11 to h13 so that the temperatures of the heaters h11 to h13 become, for example, the temperatures set via the operation unit 51.

[0028] Also, the resin supplied into the cylinder 11 is gradually pressurized from the resin pressure increase start position in the screw body 21 to the front end of the screw body 21. The pressure increase start position is at a position a predetermined distance behind from the pressure member 24, and is displaced according to the ratio (synchronization rate) of the rotation speed of the screw 20 and the rotation speed of the feed screw 85, etc. When the pressure increase start position is within a predetermined range from the pressure member 24, the molten state of the resin is stabilized and the weight of the molded product is stabilized.

[0029] The resin advanced along the screw groove 26 of the screw 20 passes through the resin flow path between the pressure member 24 and the cylinder 11, is kneaded therebetween, and then is advanced through the resin flow path between the cylinder 11 and the rod portion 32. Thereafter, the resin is sent to the front side of the screw 20 and accumulated in the front portion of the cylinder. As the molten resin accumulates on the front side of the screw 20, the screw 20 retreats.

[0030] In the metering process, the motor control unit 47 of the control device 40 controls the current supplied to the injection motor 71 so that the back pressure of the screw 20 becomes the back pressure set via the operation unit 51, for example. By applying back pressure to the screw 20, rapid retreat of the screw 20 is suppressed, the kneading property of the resin is improved, and gas in the resin easily escapes to the rear side.

[0031] The motor control unit 47 monitors the position of the screw 20 with a position sensor (not shown) while retreating the screw 20. When the screw 20 retreats to the metering completion position and a predetermined amount of resin is accumulated on the front side of the screw 20, the control device 40 stops driving the metering motor 61. As a result, the rotation of the screw 20 stops and the metering process is completed. It can be exemplified that the motor control unit 47 stops driving the feed motor 86 and stops the rotation of the feed screw 85 simultaneously with the completion of the metering process.

[0032] In the filling process, the motor control unit 47 of the control device 40 drives the injection motor 71, advances the screw 20, and pushes the resin into the cavity space in the mold device in the mold-clamped state. At this time, the motor control unit 47 controls the current supplied to the injection motor 71 so that the moving speed of the screw 20 in the rotational axis direction becomes the moving speed set via the operation unit 51, for example.

[0033] In the pressure holding process, the motor control unit 47 controls the current supplied to the injection motor 71 so that the pressure of the resin becomes the pressure set via the operation unit 51, for example. As a result, the resin filled in the cavity space shrinks due to cooling, but the shrunk portion of the resin is replenished.

[0034] In addition, the set values such as rotational speed, moving speed, pressure, etc. that the motor control unit 47 uses when controlling various motors, and the set value of temperature that the heater control unit 48 uses when controlling the heaters h11 to h13 are stored in the ROM 42, the storage unit 44, etc. as molding parameters.

[0035] 《Inspection Device 100》 As shown in FIG. 1, the inspection device 100 includes an imaging device 110 that images the molded product 3, and a processing device 120 that processes the image output from the imaging device 110.

[0036] (Imaging Device 110) FIG. 3 is a diagram showing an example of the schematic configuration of the imaging device 110. The imaging device 110 includes a light source 111 that generates light, a linear polarizer 112 that creates linearly polarized light from the light emitted from the light source 111, a wave plate 113 that converts the linearly polarized light created by the linear polarizer 112 into circularly polarized light, and a polarization camera 114.

[0037] The light source 111 can be exemplified by illumination such as a lamp, an incandescent bulb, a fluorescent lamp, an LED, etc. The light generated from the light source 111 is not limited to visible light and may be infrared light. It is desirable that the wavelength is light in the range of 360 to 900 nm. The linear polarizer 112 is an optical element that creates linearly polarized light from the light emitted from the light source 111. The wave plate 113 can be exemplified by a λ / 4 plate that produces a phase difference of 90 degrees.

[0038] The polarization camera 114 can be exemplified as a camera in which polarizers at 0 degrees, 45 degrees, 90 degrees, and 135 degrees are regularly arranged between the imaging element and the lens, and images corresponding to the above four polarization angles can be acquired in one imaging, and an image obtained by calculating (for example, arithmetic operations, trigonometric function operations, inverse trigonometric function operations) the polarization direction and polarization degree using these images can be generated.

[0039] In the imaging device 110 configured as described above, the molded product 3 molded by the injection molding machine 2 is disposed above the wave plate 113, and the light transmitted through the molded product 3 is imaged by the polarization camera 114. Then, the polarization camera 114 outputs to the processing device 120 an image obtained by calculating the polarization direction and degree of polarization using the images corresponding to the four polarization angles described above.

[0040] FIG. 4 is a diagram showing an example of an image output from the imaging device 110. FIG. 4 shows an example of an image output from the imaging device 110 to the processing device 120 when the thin rectangular parallelepiped-shaped molded product 3 is imaged by the imaging device 110. In the imaging device 110 configured as described above, since circularly polarized light is incident on the molded product 3, the direction and degree of polarization change due to the birefringence of the molded product 3. Then, since the imaging device 110 images the light transmitted through the molded product 3 by the circularly polarized light with the polarization camera 114, a stripe image corresponding to the stress distribution according to the flow field and the crystal direction of the resin as shown in FIG. 4 is output. Therefore, according to the imaging device 110, the stress distribution due to the flow field and the crystal direction of the resin of the molded product 3 can be visualized.

[0041] In the imaging device 110, the linearly polarized light transmitted through the linear polarizer 112 may be incident on the molded product 3 without using the wave plate 113. However, when the configuration is such that linearly polarized light is incident on the molded product 3, if the principal axis direction of the molded product 3 and the polarization direction are orthogonal, light cannot pass through the molded product 3, resulting in loss of information and the possibility of not being able to output a fringe image corresponding to the stress distribution to be measured. Therefore, it is desirable to use the wave plate 113 to make circularly polarized light incident on the molded product 3. By making circularly polarized light incident on the molded product 3, a phenomenon of information loss does not occur, and it is possible to realize the output of a general-purpose fringe image independent of the molded product 3. Also, the wave plate 113 may be a λ / 2 plate. When a λ / 2 plate with the azimuth angle of the optical axis tilted by 45 degrees is used as the wave plate 113, the polarization direction can be rotated perpendicularly. Thereby, the polarization direction of the linearly polarized light transmitted through the linear polarizer 112 can be changed and made incident on the molded product 3, and the phenomenon of information loss can be suppressed. That is, when the principal axis direction of the molded product 3 and the polarization direction are orthogonal and light cannot pass through the molded product 3, a fringe image corresponding to the stress distribution to be measured cannot be output. Therefore, by using a λ / 2 plate to invert the polarization direction perpendicularly, the loss of information due to light not being able to pass through the molded product 3 can be suppressed. Also, the wave plate 113 may be a λ / 8 plate or the like that converts linearly polarized light into elliptically polarized light.

[0042] Also, it is desirable that the molded product 3, which is the object to be imaged by the imaging device 110, satisfies the following conditions (1) to (3). (1) It is transparent or translucent with respect to the wavelength of the light generated by the light source 111. (2) The birefringence due to the crystallinity of the molded product 3 is sufficiently small with respect to the birefringence due to the residual stress of the molded product 3. In other words, the molded product 3 is not distorted. This is because if a material with a large birefringence is used even in a state where no stress is applied, it is difficult to distinguish whether the birefringence is due to residual stress or due to crystallinity. (3) No external force other than the residual stress is applied to the molded product 3.

[0043] Also, if the molded product 3 is to be arranged above the wavelength plate 113, the method of arranging the molded product 3 above the wavelength plate 113 is not particularly limited. For example, it can be exemplified that the molded product 3 protruded from the mold apparatus by performing the protruding step is grasped by the arm of the robot and arranged above the wavelength plate 113 of the imaging apparatus 110. Also, a person may arrange it.

[0044] (Processing device 120) As shown in FIG. 1, the processing device 120 includes a CPU 121, a ROM 122 that stores a control program and the like, a readable RAM 123 that stores calculation results and the like, a storage unit 124 such as a hard disk, an input interface (I / F) 125, and an output interface (I / F) 126. The processing device 120 realizes various functions by causing the CPU 121 to execute a program stored in the ROM 122 or the storage unit 124 or the like.

[0045] The storage unit 124 stores a reference image that is an image of the molded product imaged by the imaging apparatus 110 and determined to be a normal product by the human eye. For example, the image shown in FIG. 4 is an example of the reference image.

[0046] As shown in FIG. 2, the processing device 120 includes a receiving unit 131 that receives an image of the molded product 3 output from the imaging apparatus 110, a determination unit 132 that determines the quality of the molded product 3 using the image of the molded product 3 received by the receiving unit 131, and an output unit 133 that outputs the result determined by the determination unit 132 to the control device 40.

[0047] The determination unit 132 calculates the similarity between the reference image stored in the storage unit 124 and the image of the molded product captured by the imaging device 110, and determines the quality of the molded product by comparing the similarity with a predetermined threshold value. The determination unit 132 can exemplify calculating the similarity using well-known methods such as MSE (Mean Squared Error), SNR, PSNR, SSIM, etc. Then, when the similarity is less than the threshold value, the determination unit 132 determines that the molded product 3 is a defective product. On the other hand, when the similarity is equal to or greater than the threshold value, the determination unit 132 determines that the molded product is a non-defective product. It can be exemplified that the threshold value is set according to the type of the molded product 3, the type of resin, etc.

[0048] The output unit 133 outputs to the control device 40 the result of whether the molded product 3 is a non-defective product or a defective product, which is determined by the determination unit 132.

[0049] FIG. 5 is a flowchart showing an example of the procedure of the inspection process performed by the processing device 120. The processing device 120 repeatedly executes this process, for example, at a predetermined control cycle (for example, every 1 second). The processing device 120 determines whether the reception unit 131 has received the image of the molded product 3 from the imaging device 110 (S501). When the image is received (YES in S501), the processing device 120 calculates the similarity between the image of the molded product 3 received in S501 and the reference image stored in the storage unit 124 (S502). Then, the processing device 120 determines whether the similarity calculated in S502 is equal to or greater than a predetermined threshold value (S503). And when the similarity is equal to or greater than the threshold value (YES in S503), the processing device 120 determines that the molded product 3 is a non-defective product (S504). On the other hand, when the similarity is less than the threshold value (NO in S503), the processing device 120 determines that the molded product 3 is a defective product (S505). Then, the processing device 120 outputs to the control device 40 the determination result of whether the molded product 3 is a non-defective product or a defective product (S506). The processes of S502, S503, S504, and S505 are the processes performed by the determination unit 132, and the process of S506 is the process performed by the output unit 133. On the other hand, when the image has not been received (NO in S501), the processing device 120 ends the inspection process.

[0050] As described above, the inspection device 100 includes a linear polarizer 112 and a wave plate 113 as an example of a generation means for generating polarized light from the light emitted from the light source 111, and a polarization camera 114 that images the light transmitted through the molded product 3 molded by the injection molding machine 2 with the polarized light generated by the linear polarizer 112 and the wave plate 113, and a determination unit 132 that determines the state of the molded product 3 using the image captured by the polarization camera 114. Further, the inspection method by the inspection device 100 generates polarized light from the light emitted from the light source 111, images the light transmitted through the molded product 3 with the generated polarized light using the polarization camera 114, and determines the state of the molded product 3 using the image captured by the polarization camera 114.

[0051] According to the inspection device 100 and the inspection method configured as described above, the polarization camera 114 can output an image corresponding to the flow field and the stress distribution due to the crystal direction of the resin, and the determination unit 132 determines the state of the molded product 3 using this image. Therefore, it is possible to accurately determine whether the molded product 3 has been molded normally. Further, according to the image shown in FIG. 4 output by the polarization camera 114, many quantitative indexes such as defect information and stress information can be obtained. In addition, since the image shown in FIG. 4 is output by imaging with the polarization camera 114, many quantitative indexes can be easily obtained.

[0052] Note that the inspection timing for inspecting whether the molded product 3 molded by the injection molding machine 2 is molded normally is not particularly limited. For example, it can be exemplified that the molded product 3 protruded from the mold device is inspected every cycle. Alternatively, it may be inspected every predetermined cycle. The predetermined cycle can be exemplified as 10 cycles, 50 cycles, or 100 cycles. Also, it may be inspected every predetermined period. The predetermined period can be exemplified as one day or one week. For example, it can be exemplified that the inspection is performed at a predetermined time every day (for example, 5:00 p.m.) or at a predetermined time every Friday (for example, 5:00 p.m.).

[0053] Regarding the inspection target, when there are a plurality of molded products 3 protruded from the mold device, any one or more molded products 3 extracted therefrom may be inspected, or all the molded products 3 may be inspected.

[0054] Note that in the above-described embodiment, the polarization camera 114 outputs an image obtained by calculating the polarization direction and polarization degree using images corresponding to four polarization angles, and the processing device 120 determines the quality of the molded product 3 using the image output from the polarization camera 114. However, it is not particularly limited to such a mode. For example, the polarization camera 114 may output images corresponding to four polarization angles to the processing device 120, and the processing device 120 may generate an image obtained by calculating the polarization direction and polarization degree using the images corresponding to the four polarization angles, and determine the quality of the molded product 3 using the generated image.

[0055] (Parameter Modifying Unit 49 of Control Device 40) The parameter modifying unit 49 uses the determination result output from the processing device 120 that the molded product 3 is a defective product and the molding parameters when the molded product 3 is molded in the injection molding machine 2 to modify the molding parameters when the molded product 3 is molded after the next time.

[0056] When the determination result that the molded product 3 is a defective product is output from the processing device 120, the parameter correction unit 49 determines that the molding parameters when the molded product 3 was molded in the injection molding machine 2 are not good. Examples of the molding parameters can be the moving speed of the screw 20 in the filling process and the temperatures of the heaters h11 to h13. For example, it is conceivable that the mold device for the molded product 3 is worn, and the stress distribution changes due to the deterioration of the fluidity of the molten resin in the mold device. Therefore, the parameter correction unit 49 can be exemplified as changing at least one of the moving speed of the screw 20 and the temperatures of the heaters h11 to h13. This is because when the moving speed of the screw 20 increases, the fluidity of the molten resin in the mold device improves, and when the temperatures of the heaters h11 to h13 increase and the temperature of the molten resin increases, the fluidity of the molten resin in the mold device improves.

[0057] FIG. 6 is a diagram showing an example of an image of the molded product 3 determined to be a defective product by the determination unit 132 of the processing device 120. For example, consider the case where the receiving unit 131 of the processing device 120 receives the image of the molded product 3 shown in FIG. 6 from the imaging device 110. The determination unit 132 of the processing device 120 calculates the similarity between the image of the molded product 3 shown in FIG. 6 and the reference image stored in the storage unit 124. Then, the determination unit 132 compares the similarity with a predetermined threshold value, and determines that the molded product 3 is a defective product when the similarity is less than the threshold value. Then, the output unit 133 of the processing device 120 outputs the determination result that the molded product 3 is a defective product, determined by the determination unit 132, to the control device 40.

[0058] In the control device 40, when a determination result that the molded product 3 is a defective product is output from the processing device 120, the parameter correction unit 49 corrects the molding parameters. For example, assuming that the molded product 3 has become a defective product because the fluidity of the molten resin in the mold device for the molded product 3 has deteriorated, the parameter correction unit 49 corrects the setting value of the moving speed of the screw 20 when the defective molded product 3 was molded, which is stored in the ROM 42, the storage unit 44, etc., so that the moving speed becomes larger than that value. The parameter correction unit 49 stores the corrected moving speed of the screw 20 in the ROM 42, the storage unit 44, etc.

[0059] Note that the parameter correction unit 49 may determine whether to change either the moving speed of the screw 20 or the temperatures of the heaters h11 to h13, or to change both the moving speed of the screw 20 and the temperatures of the heaters h11 to h13, based on the type of the molded product 3, the type of the resin, or other molding parameters. Also, the parameter correction unit 49 may determine how much to change the molding parameters based on the difference between the calculated similarity and the threshold value, and the larger the difference, the greater the change in the molding parameters.

[0060] As described above, the injection molding system 1 includes the inspection device 100, a determination result that the molded product 3 output from the inspection device 100 is a defective product, and a parameter correction unit 49 that corrects the molding parameters using the molding parameters when the molded product 3 was molded in the injection molding machine 2. According to the injection molding system 1 configured in this way, the molding parameters can be determined autonomously.

[0061] Note that in the above-described embodiment, the inspection device 100 has the imaging device 110 and the processing device 120, but it is not limited to such an aspect. For example, the control device 40 of the injection molding machine 2 may have the functions of the processing device 120. For example, the control device 40 has a receiving unit 131 that receives an image of the molded product 3 output from the imaging device 110, and a determination unit 132 that determines the quality of the molded product 3 using the image of the molded product 3, and the parameter correction unit 49 may correct the molding parameters based on the determination result of the determination unit 132. Further, in such a configuration, it is preferable that the image of the molded product 3 as shown in FIGS. 4 and 6 output from the imaging device 110 can be displayed on the display unit 52. Thereby, the user can view the image displayed on the display unit 52 and correct the molding parameters via the operation unit 51.

[0062] (Variation of pass / fail determination) The processing device 120 may determine the quality of the molded product 3 in the following aspects (1) to (3). (1) Store the stress distribution of the molded product 3, which is a good product obtained by simulation such as CAE, in the storage unit 124 as a reference stress distribution. Then, the determination unit 132 calculates the similarity between the reference stress distribution stored in the storage unit 124 and the stress distribution obtained from the streak image of the molded product 3 captured by the imaging device 110, and determines the quality of the molded product 3 by comparing the similarity with a predetermined threshold value.

[0063] (2) Store, in the storage unit 124 as a reference image, the stress distribution of the molded product 3, which is a good product obtained by simulation such as CAE, converted into a streak image. Then, the determination unit 132 calculates the similarity between the reference image stored in the storage unit 124 and the streak image of the molded product 3 captured by the imaging device 110 using well-known methods such as MSE, SNR, PSNR, and SSIM, and determines the quality of the molded product 3 by comparing the similarity with a predetermined threshold value.

[0064] Using the stripe image of the molded product 3 determined to be a normal product as training data, the output means for outputting a pseudo-image similar to the normal product is trained and stored in the storage unit 124. Then, the similarity between the pseudo-image generated by inputting the stripe image of the molded product 3 captured by the imaging device 110 into the output means and the stripe image of the molded product 3 captured by the imaging device 110 which is the real image is calculated, and the quality of the molded product 3 is determined by comparing the similarity with a predetermined threshold value.

[0065] Even in the aspects (1) to (3) described above, the quality of the molded product 3 can be determined with high accuracy.

[0066] <Second Embodiment> FIG. 7 is a diagram showing an example of the schematic configuration of the inspection device 200 according to the second embodiment. The inspection device 200 according to the second embodiment is different from the inspection device 100 according to the first embodiment in that the imaging device 110 is different. Hereinafter, the differences from the first embodiment will be described. The same components in the first and second embodiments are denoted by the same reference numerals, and the detailed description thereof is omitted.

[0067] The imaging device 210 according to the second embodiment includes a light source 111, a linear polarizer 112, a polarization camera 114, and a rotation means 215 for rotating the linear polarizer 112. The rotation means 215 rotates the film-shaped linear polarizer 112 by 45 degrees, 90 degrees, and 135 degrees about a line perpendicular to the plate surface as the rotation center.

[0068] In the imaging device 210 configured as described above, the molded product 3 molded by the injection molding machine 2 is disposed above the linear polarizer 112, and the light transmitted through the molded product 3 is imaged by the polarization camera 114. Further, the rotation means 215 rotates the linear polarizer 112 by 45 degrees, 90 degrees, and 135 degrees, and the light transmitted through the molded product 3 at each rotation angle is imaged by the polarization camera 114. The polarization camera 114 outputs to the processing device 120 images corresponding to the above four polarization angles at rotation angles of 0 degrees, 45 degrees, 90 degrees, and 135 degrees, and images obtained by calculating the polarization direction and degree of polarization using these images. Note that the configuration and rotation method of the rotation means 215 for rotating the linear polarizer 112 are not particularly limited. A robot may rotate the linear polarizer 112, or a person may rotate it by hand.

[0069] Also in the imaging device 210 configured as described above, streak images corresponding to the flow field and stress distribution due to the crystal direction of the resin as shown in FIG. 4 can be output. Then, the determination unit 132 determines the state of the molded product 3 using this image, so that it is possible to accurately determine whether or not the molded product 3 has been molded normally.

[0070] <Third Embodiment> FIG. 8 is a diagram showing an example of the schematic configuration of the inspection device 300 according to the third embodiment. The inspection device 300 according to the third embodiment is different from the inspection device 100 according to the first embodiment in that the imaging device 110 is different. Hereinafter, differences from the first embodiment will be described. The same components in the first embodiment and the third embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0071] The imaging device 310 according to the third embodiment includes a light source 111, a linear polarizer 112, a polarization camera 114, and a rotation means 315 for rotating the molded product 3. The rotation means 315 rotates the molded product 3 by 45 degrees, 90 degrees, and 135 degrees about an axis perpendicular to the plate surface of the film-shaped linear polarizer 112 as the rotation center.

[0072] In the imaging device 310 configured as described above, the molded product 3 molded by the injection molding machine 2 is disposed above the linear polarizer 112, and the light transmitted through the molded product 3 is imaged by the polarization camera 114. Further, the rotation means 315 rotates the molded product 3 by 45 degrees, 90 degrees, and 135 degrees, and the light transmitted through the molded product 3 at each rotation angle is imaged by the polarization camera 114. The polarization camera 114 outputs to the processing device 120 images corresponding to the above four types of polarization angles at rotation angles of 0 degrees, 45 degrees, 90 degrees, and 135 degrees, and images obtained by calculating the polarization direction and polarization degree using these images. Note that the configuration and rotation method of the rotation means 315 for rotating the molded product 3 are not particularly limited. A robot may rotate the molded product 3, or a person may rotate it by hand.

[0073] Also in the imaging device 310 configured in this manner, as shown in FIG. 4, it is possible to output a stripe image corresponding to the stress distribution due to the flow field and the crystal direction of the resin. Then, by the determination unit 132 determining the state of the molded product 3 using this image, it is possible to accurately determine whether or not the molded product 3 has been molded normally.

[0074] <Fourth Embodiment> FIG. 9 is a diagram showing an example of the schematic configuration of an inspection device 400 according to the fourth embodiment. The inspection device 400 according to the fourth embodiment is different from the inspection device 100 according to the first embodiment in that it includes an imaging device 410 corresponding to the imaging device 110 and a processing device 450 corresponding to the processing device 120. Hereinafter, the differences from the first embodiment will be described. The same components in the first embodiment and the fourth embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0075] The imaging device 410 according to the fourth embodiment includes a light source 111, a linear polarizer 112, and a wave plate 113. The imaging device 410 also includes a first beam splitter 421 that reflects a part of the light emitted from the light source 111 and transmits a part thereof, a second beam splitter 422 that reflects a part of the light transmitted through the first beam splitter 421 and transmits a part thereof, and a third beam splitter 423 that reflects a part of the light transmitted through the second beam splitter 422 and transmits a part thereof. The imaging device 410 further includes a first linear polarizer 431 that creates linearly polarized light from the light reflected by the first beam splitter 421, and a first camera 441 that images the light transmitted through the first linear polarizer 431. The imaging device 410 also includes a second linear polarizer 432 that creates linearly polarized light from the light reflected by the second beam splitter 422, and a second camera 442 that images the light transmitted through the second linear polarizer 432. The imaging device 410 further includes a third linear polarizer 433 that creates linearly polarized light from the light reflected by the third beam splitter 423, and a third camera 443 that images the light transmitted through the third linear polarizer 433. The imaging device 410 also includes a fourth linear polarizer 434 that creates linearly polarized light from the light transmitted through the third beam splitter 423, and a fourth camera 444 that images the light transmitted through the fourth linear polarizer 434.

[0076] The first camera 441 to the fourth camera 444 each include an imaging element and a lens, but unlike the polarization camera 114, they are general cameras that do not have polarizers at 0 degrees, 45 degrees, 90 degrees, and 135 degrees respectively. The polarization axis (transmission axis) of the second linear polarizer 432 is inclined 45 degrees with respect to the polarization axis of the first linear polarizer 431. The polarization axis (transmission axis) of the third linear polarizer 433 is inclined 90 degrees with respect to the polarization axis of the first linear polarizer 431. The polarization axis (transmission axis) of the fourth linear polarizer 434 is inclined 135 degrees with respect to the polarization axis of the first linear polarizer 431.

[0077] In the imaging device 410 configured as described above, the molded product 3 molded by the injection molding machine 2 is disposed above the wave plate 113, and the light transmitted through the molded product 3 is imaged by the first camera 441 to the fourth camera 444. Then, the first camera 441 to the fourth camera 444 each output the captured image to the processing device 450.

[0078] The processing device 450 is different in that it performs a process of generating an image in which the polarization direction and the degree of polarization are calculated using the images captured by the first camera 441 to the fourth camera 444 with respect to the processing device 120. More specifically, the processing device 450 includes a receiving unit 451 that receives the images of the molded product 3 output from each of the first camera 441 to the fourth camera 444, and an image generation unit 455 that generates an image in which the polarization direction and the degree of polarization are calculated using the images captured by each of the first camera 441 to the fourth camera 444 received by the receiving unit 451. Further, the processing device 450 includes a determination unit 452 that determines the quality of the molded product 3 using the image generated by the image generation unit 455, and an output unit 453 that outputs the result determined by the determination unit 452 to the control device 40. The functions of the determination unit 452 and the output unit 453 are the same as those of the determination unit 132 and the output unit 133, respectively.

[0079] According to the inspection device 400 configured as described above, the image generation unit 455 can generate a streak image corresponding to the stress distribution due to the flow field and the crystal direction of the resin as shown in FIG. 4 using the image output from the imaging device 410. Then, by the determination unit 452 determining the state of the molded product 3 using this image, it is possible to accurately determine whether or not the molded product 3 has been molded normally.

Explanation of Signs

[0080] 1... Injection molding system, 2... Injection molding machine, 3... Molded product, 10... Injection device, 20... Screw, 40... Control device, 49... Parameter correction unit, 60... Drive device, 61... Metering motor, 71... Injection motor, 100, 200, 300, 400... Inspection device, 110, 210, 310, 410... Imaging device, 111... Light source, 112... Linear polarizer, 113... Wave plate, 114... Polarization camera, 120, 450... Processing device, 131, 451... Receiver, 132, 452... Judgment unit, 133, 453... Output unit, 215, 315... Rotating means, h11, h12, h13... Heater

Claims

An inspection apparatus for a molded product molded by an injection molding machine, a linear polarizer that generates linearly polarized light from light emitted from a light source, and a wave plate that changes the polarization direction of the linearly polarized light or converts the linearly polarized light into circularly polarized light, and a generation means for generating polarization; a polarization camera that images light transmitted through the molded product by the polarization generated by the generation means; a determination unit that determines the state of the molded product using the image captured by the polarization camera; An inspection apparatus comprising the same.

2. The wave plate is a λ / 4 wave plate that converts the linearly polarized light into circularly polarized light The inspection apparatus according to claim 1.

3. An injection molding machine, The inspection apparatus according to claim 1 or 2 for inspecting a molded product molded by the injection molding machine, An injection molding system comprising the same.

4. An inspection method for a molded product molded by an injection molding machine, generating linearly polarized light from light emitted from a light source, and generating polarization by changing the polarization direction of the linearly polarized light or converting the linearly polarized light into circularly polarized light, imaging, with a polarization camera, light transmitted through the molded product by the generated polarization, determining the state of the molded product using the image captured by the polarization camera, An inspection method.

Images