Inspection apparatus, injection molding system, and inspection method

The inspection apparatus includes: a linear polarizer and a wave plate generating polarized light from light emitted from a light source; a polarization camera imaging the polarized light generated by the linear polarizer and the wave plate and transmitted through a molding product; and a determination unit determining a state of the molding product using an image captured by the polarization camera.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2021-144030, filed on Sep. 3, 2021, which is incorporated by reference herein in its entirety.

BACKGROUND

Technical Field

Certain embodiments of the present invention relate to an inspection apparatus, an injection molding system, and an inspection method.

Description of Related Art

For example, the related art describes an injection molding machine including a cylinder for heating a resin with which a mold unit is filled and a monitoring device monitoring the situation in the cylinder based on a ratio of a refractive index of a molding product formed of the resin to a reference refractive index set in accordance with the type of the resin.

In addition, the related art describes a molding condition setting value correction apparatus used in an injection molding machine controlling an injection molding process based on a setting value and having a light source irradiating an injection molding product via a polarizing plate, imaging unit imaging the injection molding product via a polarizing plate, and setting value correction unit correcting the setting value based on a polarization stripe pattern obtained by the imaging means.

SUMMARY

According to an embodiment of the present invention, there is provided an inspection apparatus including: generating unit generating polarized light from light emitted from a light source; a polarization camera imaging the polarized light generated by the generating unit and transmitted through a molding product; and a determination unit determining a state of the molding product using an image captured by the polarization camera.

DETAILED DESCRIPTION

Against the background of, for example, corporate competitiveness enhancement and voluntary efforts related to volatile organic compound (VOC) emission reduction, resin molding apparatuses are required to be equipped with an autonomous molding mechanism capable of autonomous molding parameter determination. For autonomous molding parameter determination for realizing an autonomous molding mechanism, it is desirable to determine with high accuracy whether or not a molding product is normally molded.

The present invention is to provide an inspection apparatus, or the like, with which it can be determined with high accuracy whether or not a molding product is normally molded.

One Embodiment

FIG.1is a diagram illustrating an example of a schematic configuration of an injection molding system1according to one embodiment.

FIG.2is an example of a block diagram illustrating functions of a control device40and of a processing device120.

The injection molding system1includes an injection molding machine2and an inspection apparatus100inspecting whether or not a molding product3(seeFIG.3) molded by the injection molding machine2is normally molded.

First, the injection molding machine2will be described. In the following description, a direction of resin injection is defined as a front side, and a direction opposite to the resin injection direction is defined as a rear side.

The injection molding machine2includes a mold clamping unit (not illustrated), an injection unit10, a material supply device81, the control device40controlling the entire apparatus, an operation unit51receiving an input operation from a user, and a display unit52displaying an operation reception screen or an image.

The mold clamping unit, the injection unit10, the material supply device81, and the control device40will be described in detail later.

The operation unit51can be exemplified by an input device such as a button, a switch, and a touch panel. The display unit52can be exemplified by a liquid crystal display or an organic EL display. The operation unit51and the display unit52may be configured integrally.

The injection molding machine2has a mold closing process, a mold clamping process, a filling process, a holding pressure process, a cooling process, a plasticizing process, a mold opening process, and an ejection process as one cycle and repeatedly manufactures the molding product3. The mold closing process is a process of closing a mold unit configured by a stationary mold and a movable mold. The mold clamping process is a process of clamping the mold unit. The filling process is a process of pouring a molten resin into the mold unit. The holding pressure process is a process of applying pressure to the poured resin. The cooling process is a process of solidifying the resin in the mold unit after the holding pressure process. The plasticizing process is a process of plasticizing the molten resin for the next molding product3. The mold opening process is a process of opening the mold unit. The ejection process is a process of ejecting the molding product3from the mold unit after the mold opening. It should be noted that the plasticizing process may be performed during the cooling process so that the molding cycle is shortened.

Mold Clamping Unit

The mold clamping unit, which includes a stationary platen to which a stationary mold is attached and a movable platen to which a movable mold is attached, performs mold closing, mold clamping, and mold opening by causing the movable platen to advance and retreat and causing the movable mold to come into contact with or be separated from the stationary mold. The mold clamping unit is not particularly limited in terms of type. Examples thereof include 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.

The injection unit10has a cylinder11for heating a resin as a molding material and a nozzle12arranged at a front end of the cylinder11. In addition, the injection unit10has a screw20arranged in the cylinder11so as to be rotatable and capable of advancing and retreating in a rotation axis direction, heaters h11, h12, and h13as heating sources heating the cylinder11, and a drive unit60arranged on the rear side of the cylinder11.

The screw20, which has a screw main body21and an injection portion22arranged in front of the screw main body21, is connected to the drive unit60via a rear end shaft portion. The screw main body21has a flight portion23and a pressure member24arranged so as to be detachable with respect to a front end of the flight portion23. The flight portion23has a rod-shaped main body portion23aand a helical flight23bformed so as to protrude from an outer peripheral surface of the main body portion23a, and a helical screw groove26is formed along the flight23b. It can be exemplified that the depth of the screw groove26is constant and the screw compression ratio is constant from a rear end to the front end of the flight portion23.

It should be noted that the screw20may not have the pressure member24and the flight portion23may be formed over the entire screw main body21. In addition, from a rear end to a front end, the screw main body21may be divided into a supply unit where a resin is supplied, a compression zone where the supplied resin is melted while being compressed, and a metering zone where the molten resin is metered in fixed amounts. It is preferable that the depth of the screw groove26is the deepest in the supply unit, is the shallowest in the metering zone, and becomes shallow from the rear side toward the front side in the compression zone.

The injection portion22has a head portion31having a tip provided with a conical part, a rod portion32formed adjacent to the rear side of the head portion31, a check ring33arranged around the rod portion32, and a seal ring34attached to a front end of the pressure member24.

During the plasticizing process, the check ring33is moved to the front side with respect to the rod portion32and is separated from the seal ring34as the screw20moves rearward, and then the resin is sent from the rear side of the injection portion22to the front side. In addition, during the injection process, the check ring33is moved to the rear side with respect to the rod portion32and is brought into contact with the seal ring34as the screw20moves forward, and then a resin backflow is prevented.

A resin feed port14as a molding material feed port is formed in a rear portion of the cylinder11. The resin feed port14is formed at a point facing a rear end portion of the screw groove26with the screw20positioned on the foremost side in the cylinder11. The material supply device81supplying a resin into the cylinder11is attached to the resin feed port14.

The drive unit60rotates the screw20or causes the screw20to advance and retreat in the cylinder11.

The drive unit60has a plasticizing motor61as a drive source rotating the screw20in the cylinder11and an injection motor71as a drive source moving the screw20in the rotation axis direction in the cylinder11. It can be exemplified that the plasticizing motor61and the injection motor71are servomotors.

Provided between the injection motor71and the screw20is, for example, a motion conversion mechanism converting rotary motion of the injection motor71into linear motion of the screw20. For example, the motion conversion mechanism has a screw shaft and a screw nut screwing onto the screw shaft. It can be exemplified that a ball, a roller, or the like is provided between the screw shaft and the screw nut. The drive source that moves the screw20in the rotation axis direction is not limited to the injection motor71and may be, for example, a hydraulic cylinder.

Material Supply Device81

The material supply device81has a hopper82accommodating a molding material (such as resin pellets), a feed cylinder83extending in a horizontal direction from a lower end of the hopper82, and a tubular guide portion84extending downward from a front end of the feed cylinder83. In addition, the material supply device81has a feed screw85rotatably arranged in the feed cylinder83and a feed motor86rotating the feed screw85.

The resin supplied from the inside of the hopper82into the feed cylinder83is moved forward along the screw groove of the feed screw85as the feed screw85rotates. The resin sent from a front end of the feed screw85into the guide portion84drops in the guide portion84and is supplied into the cylinder11.

It should be noted that the feed cylinder83does not necessarily have to extend in the horizontal direction and may, for example, extend obliquely with respect to the horizontal direction. In addition, the feed cylinder83may be higher on an outlet side than on an inlet side. In addition, the resin supplied into the feed cylinder83may be heated by a heater (not illustrated). At this time, the resin is preferably heated to a non-melting temperature such as a predetermined temperature equal to or lower than the glass transition point.

The control device40has a CPU41, a ROM42storing a control program or the like, a readable and writable RAM43storing a calculation result or the like, a storage unit44such as a hard disk, an input interface (I/F)45, and an output interface (I/F)46. The control device40implements various functions by causing the CPU41to execute a program stored in the ROM42, the storage unit44, or the like.

The control device40has a motor control unit47controlling the drive of the plasticizing motor61, the injection motor71, the feed motor86, and the like, a heater control unit48controlling the temperatures of the heaters h11to h13, and a parameter correction unit49correcting a molding parameter in molding the molding product3. The functions of the motor control unit47and the heater control unit48will be described in association with the operation of the injection molding machine2to be described below. The parameter correction unit49will be described in detail later.

Operation of Injection Molding Machine2

The operation of the injection molding machine2controlled by the control device40will be described below. In the plasticizing process, the motor control unit47of the control device40drives the plasticizing motor61to rotate the screw20. At this time, the motor control unit47drives the feed motor86to rotate the feed screw85. It can be exemplified that the motor control unit47synchronously rotates the screw20and the feed screw85during molding. The motor control unit47controls the current supplied to the plasticizing motor61such that the rotational speed of the screw20reaches, for example, a rotational speed set via the operation unit51. In addition, the motor control unit47controls the current supplied to the feed motor86such that the rotational speed of the feed screw85reaches, for example, a rotational speed set via the operation unit51.

The resin supplied into the cylinder11by the material supply device81is immediately sent to the front side by the screw20without staying at the resin feed port14. The screw groove26of the screw20is not densely filled with the resin, and the resin in the screw groove26is in a sparse state. Accordingly, the amount of the resin that is sent to the front side by the screw20per unit time increases as the speed of the resin supply by the material supply device81increases.

The resin supplied into the cylinder11is moved forward along the screw groove26of the screw20as the screw20rotates and is heated and melted by the heaters h11to h13. The heater control unit48of the control device40controls the electric power supplied to the heaters h11to h13such that the temperatures of the heaters h11to h13reach, for example, temperatures set via the operation unit51.

In addition, the resin supplied into the cylinder11is gradually pressurized from the pressure rise start position of the resin in the screw main body21to the front end of the screw main body21. The pressure rise start position is at a predetermined distance to the rear side from the pressure member24and is displaced in accordance with, for example, the ratio (synchronization rate) between the rotational speed of the screw20and the rotational speed of the feed screw85. On the condition that the pressure rise start position is at a distance within a predetermined range from the pressure member24, the molten state of the resin is stabilized, and the weight of the molding product is stabilized.

The resin moved forward along the screw groove26of the screw20passes through the resin flow path between the pressure member24and the cylinder11, is mixed therebetween, and then passes through the resin flow path between the cylinder11and the rod portion32and is moved forward. Then, the resin is sent to the front side of the screw20and is accumulated in the cylinder front portion. The screw20moves rearward as the molten resin is accumulated on the front side of the screw20.

In the plasticizing process, the motor control unit47of the control device40controls the current supplied to the injection motor71such that the back pressure of the screw20reaches, for example, a back pressure set via the operation unit51. By back pressure application to the screw20, a rapid rearward movement of the screw20is suppressed, the kneadability of the resin is improved, and gas in the resin is capable of easily escaping to the rear side.

The motor control unit47monitors the position of the screw20with a position sensor (not illustrated) while the screw20is moved rearward. The control device40stops the drive of the plasticizing motor61when the screw20is moved rearward up to the plasticizing completion position and a predetermined amount of resin is accumulated on the front side of the screw20. As a result, the rotation of the screw20is stopped, and the plasticizing process is completed. It can be exemplified that the motor control unit47stops the drive of the feed motor86and stops the rotation of the feed screw85simultaneously with the plasticizing process completion.

In the filling process, the motor control unit47of the control device40drives the injection motor71to move the screw20forward and to push the resin into a cavity space in the mold unit that is clamped. At that time, the motor control unit47controls the current supplied to the injection motor71such that the movement speed of the screw20in the rotation axis direction reaches, for example, a movement speed set via the operation unit51.

In the holding pressure process, the motor control unit47controls the current supplied to the injection motor71such that the pressure of the resin reaches, for example, a pressure set via the operation unit51. As a result, the resin with which the cavity space is filled shrinks by cooling, and yet resin replenishment is performed by the shrinkage amount.

It should be noted that the setting values that the motor control unit47uses in controlling the various motors (e.g., rotational speed, movement speed, pressure) and the temperature setting value that the heater control unit48uses in controlling the heaters h11to h13are stored as molding parameters in, for example, the ROM42or the storage unit44.

As illustrated inFIG.1, the inspection apparatus100has an imaging device110imaging the molding product3and the processing device120processing the image output from the imaging device110.

FIG.3is a diagram illustrating an example of a schematic configuration of the imaging device110.

The imaging device110has a light source111generating light, a linear polarizer112producing linearly polarized light from the light emitted from the light source111, a wave plate113converting the linearly polarized light produced by the linear polarizer112into circularly polarized light, and a polarization camera114.

The light source111can be exemplified by lighting such as a lamp, an incandescent lamp, a fluorescent lamp, and an LED. The light emitted from the light source111is not limited to visible light and may be infrared light. Light with a wavelength of 360 to 900 nm is desirable. The linear polarizer112is an optical element producing linearly polarized light from the light emitted from the light source111.

The wave plate113can be exemplified as a λ/4 plate producing a phase difference of 90 degrees.

As for the polarization camera114, polarizers of 0, 45, 90, and 135 degrees are regularly disposed between an imaging element and a lens, images corresponding to the four polarization angles can be acquired by single imaging, and a camera capable of generating an image obtained by calculating the direction and degree of polarization using the images can be exemplified (e.g., the four basic arithmetic operations, trigonometric function operations, and inverse trigonometric function operations).

In the imaging device110configured as described above, the molding product3molded by the injection molding machine2is disposed above the wave plate113, and the light transmitted through the molding product3is imaged by the polarization camera114. Then, the polarization camera114outputs, to the processing device120, an image obtained by calculating the direction and degree of polarization using the images corresponding to the four polarization angles.

FIG.4is a diagram illustrating an example of the image output from the imaging device110.FIG.4illustrates an example of the image output from the imaging device110to the processing device120in a case where the molding product3that has a thin rectangular parallelepiped shape is imaged by the imaging device110.

In the imaging device110configured as described above, circularly polarized light is made incident into the molding product3and, as a result, the birefringence of the molding product3changes the direction and degree of polarization. Then, the imaging device110images the circularly polarized light transmitted through the molding product3with the polarization camera114, and output as a result is a striped image corresponding to the stress distribution attributable to a flow field or a crystal direction of the resin as illustrated inFIG.4. Accordingly, with the imaging device110, it is possible to visualize the stress distribution attributable to the flow field of the molding product3or the crystal direction of the resin.

It should be noted that in the imaging device110, linearly polarized light transmitted through the linear polarizer112may be made incident into the molding product3without using the wave plate113. However, in the case of a configuration in which linearly polarized light is made incident into the molding product3, the light cannot be transmitted through the molding product3in a case where a main axis direction of the molding product3is orthogonal to a polarization direction, and thus information is lost and it may be impossible to output a striped image corresponding to the stress distribution to be measured. Accordingly, it is desirable to make circularly polarized light incident into the molding product3using the wave plate113. By making circularly polarized light incident into the molding product3, no information loss phenomenon occurs, and thus it is possible to output a general-purpose striped image that does not depend on the molding product3. In addition, the wave plate113may be a λ/2 plate. The polarization direction can be vertically rotated when a λ/2 plate with an optical axis tilted to an azimuth angle of 45 degrees is used as the wave plate113. As a result, the linearly polarized light transmitted through the linear polarizer112can be made incident into the molding product3with the polarization direction changed, and an information loss phenomenon can be suppressed. In other words, in a state where the main axis direction of the molding product3is orthogonal to the polarization direction and no light can be transmitted through the molding product3, it is impossible to output a striped image corresponding to the stress distribution to be measured, and thus it is possible to suppress information loss attributable to light being incapable of transmission through the molding product3by vertically inverting the direction of polarization using a λ/2 plate. In addition, the wave plate113may be, for example, a λ/8 plate converting linearly polarized light into elliptically polarized light.

In addition, it is desirable that the molding product3as an imaging target of the imaging device110satisfies the following conditions (1) to (3).

(1) The molding product3is transparent or translucent with respect to the wavelength of the light generated by the light source111.

(2) The birefringence derived from the crystallinity of the molding product3is sufficiently small with respect to the birefringence attributable to the residual stress of the molding product3. That is, the molding product3is not distorted. This is because it is difficult to distinguish whether the birefringence is residual stress-derived or crystallinity-derived when a substance large in birefringence even in an unstressed state is used.

(3) No external force other than residual stress is applied to the molding product3.

In addition, how to dispose the molding product3above the wave plate113is not particularly limited insofar as the molding product3is disposed above the wave plate113. For example, it can be exemplified that the molding product3ejected from the mold unit as a result of the ejection process is grasped by a robot arm and is disposed above the wave plate113of the imaging device110. In addition, the disposition may be performed by a person.

As illustrated inFIG.1, the processing device120includes a CPU121, a ROM122storing a control program or the like, a readable and writable RAM123storing a calculation result or the like, a storage unit124such as a hard disk, an input interface (I/F)125, and an output interface (I/F)126. The processing device120implements various functions by causing the CPU121to execute a program stored in the ROM122, the storage unit124, or the like.

The storage unit124stores a reference image, which is obtained by the imaging device110imaging a molding product determined to be normal by human eyes. For example, the image illustrated inFIG.4is an example of the reference image.

As illustrated inFIG.2, the processing device120has a receiving unit131receiving the image of the molding product3output from the imaging device110, a determination unit132determining the quality of the molding product3using the image of the molding product3received by the receiving unit131, and an output unit133outputting the determination result of the determination unit132to the control device40.

The determination unit132calculates the degree of similarity between the reference image stored in the storage unit124and the image of the molding product captured by the imaging device110and determines the quality of the molding product via comparison between the degree of similarity and a predetermined threshold. It can be exemplified that the determination unit132calculates the degree of similarity using known mean squared error (MSE), SNR, PSNR, SSIM, or the like. Then, in a case where the degree of similarity is lower than the threshold, the determination unit132determines that the molding product3is defective. On the other hand, in a case where the degree of similarity is equal to or higher than the threshold, the determination unit132determines that the molding product is not defective. It should be noted that it can be exemplified that the threshold is set in accordance with, for example, the type of the molding product3or the type of the resin.

The output unit133outputs, to the control device40, the result determined by the determination unit132as to whether the molding product3is defective or not.

FIG.5is a flowchart illustrating an example of the procedure of the inspection processing that is performed by the processing device120.

The processing device120repeatedly executes this processing at, for example, a predetermined control cycle (e.g., every second).

The processing device120determines whether or not the receiving unit131has received the image of the molding product3from the imaging device110(S501). In a case where the image has been received (YES in S501), the processing device120calculates the degree of similarity between the image of the molding product3received in S501and the reference image stored in the storage unit124(S502). Then, the processing device120determines whether or not the degree of similarity calculated in S502is equal to or higher than a predetermined threshold (S503). Then, in a case where the degree of similarity is equal to or higher than the threshold (YES in S503), the processing device120determines that the molding product3is not defective (S504). On the other hand, in a case where the degree of similarity is lower than the threshold (NO in S503), the processing device120determines that the molding product3is defective (S505). Then, the processing device120outputs the determination result as to whether the molding product3is defective or not to the control device40(S506). The processing of S502, S503, S504, and S505is performed by the determination unit132, and the processing of S506is performed by the output unit133.

The processing device120ends the inspection processing in the case of no image being received (NO in S501).

As described above, the inspection apparatus100includes the linear polarizer112and the wave plate113as an example of generating unit generating polarized light from the light emitted from the light source111, the polarization camera114imaging the polarized light generated by the linear polarizer112and the wave plate113and transmitted through the molding product3molded by the injection molding machine2, and the determination unit132determining the state of the molding product3using the image captured by the polarization camera114. In addition, by the method of inspection using the inspection apparatus100, polarized light is generated from the light emitted from the light source111, the polarization camera114images the generated polarized light transmitted through the molding product3, and the state of the molding product3is determined using the image captured by the polarization camera114.

According to the inspection apparatus100and the inspection method configured as described above, the polarization camera114is capable of outputting an image corresponding to the stress distribution attributable to the flow field or the crystal direction of the resin, the determination unit132determines the state of the molding product3using this image, and thus it can be determined with high accuracy whether or not the molding product3is normally molded. In addition, according to the image illustrated inFIG.4, which is output by the polarization camera114, many quantitative indicators such as defect information and stress information can be obtained. In addition, the image illustrated inFIG.4is output by imaging with the polarization camera114, and thus many quantitative indicators can be acquired conveniently.

It should be noted that the timing of inspecting whether or not the molding product3molded by the injection molding machine2is normally molded is not particularly limited. For example, it can be exemplified that the molding product3ejected from the mold unit is inspected every cycle. Alternatively, the inspection may be performed every predetermined cycle. The predetermined cycle can be exemplified by 10, 50, or 100 cycles. Alternatively, the inspection may be performed every predetermined period. The predetermined period can be exemplified by one day or one week. For example, inspecting at a predetermined time every day (e.g., 17:00) or at a predetermined time every Friday (e.g., 17:00) can be exemplified.

In addition, as for the inspection target, in a case where a plurality of the molding products3are ejected from the mold unit, any one or more of the molding products3extracted therefrom may be inspected, or every molding product3may be inspected.

It should be noted that the polarization camera114in the above embodiment outputs an image obtained by calculating the direction and degree of polarization using images corresponding to four polarization angles, and the processing device120determines the quality of the molding product3using the image output from the polarization camera114, and yet the present invention is not particularly limited to such an aspect. For example, the polarization camera114may output images corresponding to four polarization angles to the processing device120, the processing device120may generate an image obtained by calculating the direction and degree of polarization using the images corresponding to the four polarization angles, and the quality of the molding product3may be determined using the generated image.

In a case where the processing device120outputs the determination result that the molding product3is defective, the parameter correction unit49determines that the molding parameter in molding the molding product3in the injection molding machine2is not satisfactory. It can be exemplified that the molding parameter is the movement speed of the screw20in the filling process or the temperatures of the heaters h11to h13. For example, it is conceivable that a change in stress distribution is caused by the mold unit for the molding product3wearing down and the fluidity of the molten resin in the mold unit deteriorating. Accordingly, it can be exemplified that the parameter correction unit49changes at least one of the movement speed of the screw20and the temperatures of the heaters h11to h13. This is because the fluidity of the molten resin in the mold unit improves as the movement speed of the screw20increases and the fluidity of the molten resin in the mold unit improves as the temperatures of the heaters h11to h13rise and the temperature of the molten resin rises.

FIG.6is a diagram illustrating an example of an image of the molding product3determined to be defective by the determination unit132of the processing device120.

A case is conceivable where, for example, the receiving unit131of the processing device120has received the image of the molding product3illustrated inFIG.6from the imaging device110. The determination unit132of the processing device120calculates the degree of similarity between the image of the molding product3illustrated inFIG.6and the reference image stored in the storage unit124. Then, the determination unit132compares the degree of similarity with a predetermined threshold and determines that the molding product3is defective in a case where the degree of similarity is lower than the threshold. Then, the output unit133of the processing device120outputs, to the control device40, the result that the molding product3is defective determined by the determination unit132.

It should be noted that the parameter correction unit49preferably determines whether to change the movement speed of the screw20or the temperatures of the heaters h11to h13or whether to change both the movement speed of the screw20and the temperatures of the heaters h11to h13based on the type of the molding product3, the type of the resin, or another molding parameter. In addition, the parameter correction unit49preferably determines how much to change a molding parameter based on the difference between the calculated degree of similarity and a threshold and increases the molding parameter as the difference increases.

As described above, the injection molding system1includes the inspection apparatus100and the parameter correction unit49using the determination result that the molding product3is defective output from the inspection apparatus100and a molding parameter in molding the molding product3in the injection molding machine2to correct the molding parameter. According to the injection molding system1configured in this manner, molding parameter determination can be performed autonomously.

It should be noted that although the inspection apparatus100has the imaging device110and the processing device120in the embodiment described above, the present invention is not limited to such an aspect.

For example, the control device40of the injection molding machine2may have the function of the processing device120. For example, the control device40may have the receiving unit131receiving the image of the molding product3output from the imaging device110and the determination unit132determining the quality of the molding product3using the image of the molding product3, and the parameter correction unit49may correct the molding parameter based on the determination result of the determination unit132. In addition, in the case of such a configuration, it is preferable that the image of the molding product3as illustrated inFIGS.4and6, which is output from the imaging device110, can be displayed on the display unit52. As a result, a user can view the image displayed on the display unit52and perform molding parameter correction via the operation unit51.

Modification Examples of Quality Determination

The processing device120may determine the quality of the molding product3in the following aspects (1) to (3).

(1) The stress distribution of the non-defective molding product3obtained by simulation such as CAE is stored in the storage unit124as a reference stress distribution. Then, the determination unit132calculates the degree of similarity between the reference stress distribution stored in the storage unit124and the stress distribution obtained from the striped image of the molding product3captured by the imaging device110and determines the quality of the molding product3via comparison between the degree of similarity and a predetermined threshold.

(2) A striped image converted from the stress distribution of the non-defective molding product3obtained by simulation such as CAE is stored in the storage unit124as a reference image. Then, the determination unit132calculates the degree of similarity between the reference image stored in the storage unit124and the striped image of the molding product3captured by the imaging device110using known MSE, SNR, PSNR, SSIM, or the like and determines the quality of the molding product3via comparison between the degree of similarity and a predetermined threshold.

(3) Output unit outputting a pseudo image similar to a normal product is trained using the striped image of the molding product3determined as a normal product as training data, and the output unit is stored in the storage unit124. Then, the degree of similarity is calculated between the pseudo image generated by inputting the striped image of the molding product3captured by the imaging device110to the output unit and the striped image of the molding product3captured by the imaging device110, which is an actual image, and the quality of the molding product3is determined via comparison between the degree of similarity and a predetermined threshold.

The quality of the molding product3can also be determined with high accuracy in the above aspects (1) to (3).

Another Embodiment

FIG.7is a diagram illustrating an example of a schematic configuration of an inspection apparatus200according to another embodiment. The inspection apparatus200according to another embodiment differs from the inspection apparatus100according to one embodiment in terms of the imaging device110. The difference from one embodiment will be described below. Those components common to the one and another embodiments are denoted by the same reference numerals without detailed description.

An imaging device210according to another embodiment has the light source111, the linear polarizer112, the polarization camera114, and rotating unit215for rotating the linear polarizer112. The rotating unit215rotates the film-shaped linear polarizer112by 45, 90, and 135 degrees around a line orthogonal to a plate surface as a rotation center.

In the imaging device210configured as described above, the molding product3molded by the injection molding machine2is disposed above the linear polarizer112, and the light transmitted through the molding product3is imaged by the polarization camera114. Further, the rotating unit215rotates the linear polarizer112by 45, 90, and 135 degrees, and the polarization camera114images the light transmitted through the molding product3at each rotation angle. The polarization camera114outputs, to the processing device120, images corresponding to the above four polarization angles at the rotation angles of 0, 45, 90, and 135 degrees and an image obtained by calculating the direction and degree of polarization using the images. It should be noted that the rotating unit215for rotating the linear polarizer112is not particularly limited in terms of configuration and rotation method. The linear polarizer112may be rotated by a robot or manually.

The imaging device210configured in this manner is also capable of outputting a striped image corresponding to the stress distribution attributable to the flow field or the crystal direction of the resin as illustrated inFIG.4. Then, by the determination unit132determining the state of the molding product3using this image, it can be determined with high accuracy whether or not the molding product3is normally molded.

Further Embodiment

FIG.8is a diagram illustrating an example of a schematic configuration of an inspection apparatus300according to further embodiment. The inspection apparatus300according to further embodiment differs from the inspection apparatus100according to one embodiment in terms of the imaging device110. The difference from one embodiment will be described below. Those components common to one and further embodiments are denoted by the same reference numerals without detailed description.

An imaging device310according to further embodiment has the light source111, the linear polarizer112, the polarization camera114, and rotating unit315for rotating the molding product3. The rotating unit315rotates the molding product3by 45, 90, and 135 degrees around a line orthogonal to the plate surface of the film-shaped linear polarizer112as a rotation center.

In the imaging device310configured as described above, the molding product3molded by the injection molding machine2is disposed above the linear polarizer112, and the light transmitted through the molding product3is imaged by the polarization camera114. Further, the rotating unit315rotates the molding product3by 45, 90, and 135 degrees, and the polarization camera114images the light transmitted through the molding product3at each rotation angle. The polarization camera114outputs, to the processing device120, images corresponding to the above four polarization angles at the rotation angles of 0, 45, 90, and 135 degrees and an image obtained by calculating the direction and degree of polarization using the images. It should be noted that the rotating unit315for rotating the molding product3is not particularly limited in terms of configuration and rotation method. The molding product3may be rotated by a robot or manually.

The imaging device310configured in this manner is also capable of outputting a striped image corresponding to the stress distribution attributable to the flow field or the crystal direction of the resin as illustrated inFIG.4. Then, by the determination unit132determining the state of the molding product3using this image, it can be determined with high accuracy whether or not the molding product3is normally molded.

Still Further Embodiment

FIG.9is a diagram illustrating an example of a schematic configuration of an inspection apparatus400according to still further embodiment.

The inspection apparatus400according to still further embodiment differs from the inspection apparatus100according to one embodiment in that the inspection apparatus400includes an imaging device410corresponding to the imaging device110and a processing device450corresponding to the processing device120. The difference from one embodiment will be described below. Those components common to one and still further embodiments are denoted by the same reference numerals without detailed description.

The imaging device410according to still further embodiment has the light source111, the linear polarizer112, and the wave plate113. In addition, the imaging device410has a first beam splitter421partially reflecting and partially transmitting the light emitted from the light source111, a second beam splitter422partially reflecting and partially transmitting the light transmitted through the first beam splitter421, and a third beam splitter423partially reflecting and partially transmitting the light transmitted through the second beam splitter422. In addition, the imaging device410has a first linear polarizer431producing linearly polarized light from the light reflected by the first beam splitter421and a first camera441imaging the light transmitted through the first linear polarizer431. In addition, the imaging device410has a second linear polarizer432producing linearly polarized light from the light reflected by the second beam splitter422and a second camera442imaging the light transmitted through the second linear polarizer432. In addition, the imaging device410has a third linear polarizer433producing linearly polarized light from the light reflected by the third beam splitter423and a third camera443imaging the light transmitted through the third linear polarizer433. In addition, the imaging device410has a fourth linear polarizer434producing linearly polarized light from the light transmitted through the third beam splitter423and a fourth camera444imaging the light transmitted through the fourth linear polarizer434.

Although the first camera441, the second camera442, the third camera443, and the fourth camera444have imaging elements and lenses, the first camera441, the second camera442, the third camera443, and the fourth camera444are, unlike the polarization camera114, general cameras that do not have polarizers of 0, 45, 90, and 135 degrees.

The polarization axis (transmission axis) of the second linear polarizer432is inclined by 45 degrees with respect to the polarization axis of the first linear polarizer431. The polarization axis (transmission axis) of the third linear polarizer433is inclined by 90 degrees with respect to the polarization axis of the first linear polarizer431. The polarization axis (transmission axis) of the fourth linear polarizer434is inclined by 135 degrees with respect to the polarization axis of the first linear polarizer431.

In the imaging device410configured as described above, the molding product3molded by the injection molding machine2is disposed above the wave plate113, and the light transmitted through the molding product3is imaged by the first camera441, the second camera442, the third camera443, and the fourth camera444. Then, each of the first camera441, the second camera442, the third camera443, and the fourth camera444outputs a captured image to the processing device450.

The processing device450differs from the processing device120in that the processing device450performs processing of generating an image obtained by calculating the direction and degree of polarization using the images captured by the first camera441, the second camera442, the third camera443, and the fourth camera444. More specifically, the processing device450has a receiving unit451receiving the images of the molding product3respectively output from the first camera441, the second camera442, the third camera443, and the fourth camera444and an image generating unit455generating an image obtained by calculating the direction and degree of polarization using the images respectively captured by the first camera441, the second camera442, the third camera443, and the fourth camera444and received by the receiving unit451. In addition, the processing device450has a determination unit452determining the quality of the molding product3using the image generated by the image generating unit455and an output unit453outputting the determination result of the determination unit452to the control device40. The functions of the determination unit452and the output unit453are the same as those of the determination unit132and the output unit133, respectively.

According to the inspection apparatus400configured as described above, the image generating unit455is capable of generating a striped image corresponding to the stress distribution attributable to the flow field or the crystal direction of the resin as illustrated inFIG.4using the image output from the imaging device410. Then, by the determination unit452determining the state of the molding product3using this image, it can be determined with high accuracy whether or not the molding product3is normally molded.