Method and device for optically inspecting molded parts

Abstract

Method and system for the optical inspection of molded parts (10), in particular closures or the like produced by a thermoforming or extrusion forming process, using a transmitted light method, comprising: conveying the molded parts (10) by a conveying device (50) through an optical inspection region, and recording at least one image of the molded parts (10) by a recording device (20), wherein the molded part (10) is located between the recording device (20) and the illumination device (30) and is illuminated by the illumination device, and wherein the image is evaluated by the processing device (40) in such a way that defects and / or statistical deviations from the normal distribution of the molded part (10) can be determined, such that conclusions relating to the production process of the molded part (10) in a molding tool having a cavity can be obtained, this conclusion can be used for the control of the manufacturing process.

Description

Technical Field

[0001] The invention relates to a method and a device for optically inspecting molded parts, in particular molded parts such as closure parts, which can be produced by hot forming or extrusion processes, are inspected for faults by means of transmitted light. Background Art

[0002] Plastic parts can be produced in large quantities and at high speed by known forming and deforming processes. In particular, molded parts can be produced by thermoforming, extrusion, blow molding or injection molding. Most plastic products produced worldwide are produced by injection molding, with extrusion for blow molding and film blowing also playing an important role. Flawless, high-quality molded parts require good condition of molds and machines and perfect control of the manufacturing process, which must always be checked.

[0003] In the injection molding process, the plasticized plastic is injected into a molding die having at least one cavity by means of an injection unit. The molded injection molded part is demoulded and transported away by means of a conveyor. In order to be able to detect errors (Fehler) in a timely manner and to assign them to the corresponding cavities of the molding die, it is known to keep the relative sequence of the injection molded parts until the inspection system. If a defect is found in the inspection system, the cavity from which the defective injection molded part originates can be identified and then corrected by selective control. However, this inspection is problematic for molded parts produced on a large scale.

[0004] Patent document EP2976204B1 discloses an inspection system for optical inspection of so-called preforms. Preforms are, for example, preforms for PET bottles or plastic caps, which need to be inspected for color quality, faults and dimensions. Here, the preforms are transported by a conveyor device to an inspection device, and an image acquisition device is used to capture images of the preforms in free fall or sliding along a flat plate in order to detect color quality and / or faulty preforms. However, not all faults in the manufactured preforms can be clearly detected in this way.

[0005] In principle, optical inspections using transmitted light methods are also known, in which the object to be inspected is placed between a light source and a camera. For example, in a known transmitted light method, the object to be inspected slides in the inspection area on an at least partially transparent plate or diffuser.

[0006] In addition, patent document EP2969269A also discloses an inspection method and an inspection device, wherein fast-moving processed objects are received from an inspection unit into a conveying path, and image data of each object is captured by at least one inspection camera. The inspection unit transfers the objects to a sorting unit, wherein the objects are thrown in a manner similar to free throwing, and objects identified as having errors are separated from objects identified as having no errors. These objects are transported one by one through at least one inspection camera by a conveying device, wherein the inspection camera is a daylight camera, an IR camera and / or one or more sensors for detecting color and / or size.

[0007] However, it is usually not feasible to inspect objects made of opaque materials using transmitted light methods, because the light cannot penetrate the object sufficiently. It is also disadvantageous that transmitted light inspection requires precise coordination of the transport system of the object in the inspection area, which is usually difficult to achieve. Summary of the invention

[0008] The object of the present invention is to propose a method for optically inspecting shaped parts, in particular closure parts or the like which can be produced by a thermoforming or extrusion process, in order to check their quality and / or properties, by which the above-mentioned disadvantages of the known methods can be avoided or at least greatly reduced. Furthermore, the present invention describes a system suitable for carrying out the method.

[0009] In particular, the object of the present invention is to provide a method and a corresponding system for the optical inspection of molded parts, by means of which a reliable, rapid and very simple inspection can be carried out based on an almost reflection-free image. Based on the almost reflection-free image of the molded part, various errors, defects and / or fault points that cannot be detected or can only be detected insufficiently with other methods can be determined at an early stage, even in areas that are difficult to detect and have become a trend. The molding device, the molding tool used and / or the material can be the cause of these errors, defects and / or fault points and variations. The complex interaction between the configuration of the molded part and the molding tool and between the material properties and various process parameters can lead to a variety of defects that can make the manufactured molded part unusable.

[0010] By reliably checking various error points of molded parts and / or analyzing the overall statistical data (i.e., large amounts of data) of molded parts, conclusions can be drawn about process errors in production, so that the manufacturing process can also be monitored and adjusted or controlled. By means of a closed-loop regulation and / or control system, the manufacturing process can be optimized based on the evaluation of the detected error points or statistical data.

[0011] According to the invention, these objects are achieved in particular by the subject matter of the independent claims. Further preferred embodiments are given in the dependent claims and in the description.

[0012] The object of the invention is achieved in that the method enables optical inspection of molded parts by optimal illumination in the form of transmitted light or backlighting. The object of the invention is achieved in particular by a method for optical inspection of molded parts by transmitted light, in particular closure parts or the like which are manufactured by a hot forming or extrusion process during the manufacturing process. The method comprises conveying the molded part by a conveying device through an optical inspection area and recording at least one image of the molded part by a camera device, wherein the molded part is located between the camera device and the lighting device and is illuminated by the lighting device. The image is evaluated by a processing device in order to be able to determine defects and / or statistical data of the molded part, from which conclusions can be drawn about the manufacturing process of the molded part in a molding mold with a cavity, which conclusions can be used to control the manufacturing process. For example, process parameters can be adjusted accordingly.

[0013] The images of the molded parts recorded by the camera under backlighting suppress or minimize reflections from the molded part surface, so that the recorded images can be well evaluated by the processing device. Depending on the color of the molded part, the entire wall can be checked, so that defects on the wall, the inner area and / or the opposite side can also be detected.

[0014] The images are evaluated by a processing device to check whether the molded parts are defective. In addition, algorithms can be used to statistically evaluate the data that can be collected in order to detect deviations from a normal distribution and / or a pattern, for example, from which further conclusions can be drawn and predictions can be made. The evaluation can use adjustable algorithms.

[0015] Detectable error points allow conclusions to be drawn about the manufacturing process itself, so that the process parameters of the manufacturing process can be adjusted accordingly. However, according to the invention, not only can the detectable error points be used to monitor and / or control the manufacturing process, but also the overall analysis and evaluation of the molded parts can be used. Therefore, the data of the inspected molded parts, including molded parts identified as having errors and molded parts identified as not having errors, can be analyzed by algorithms and / or artificial intelligence in order to identify deviations from the normal distribution and / or pattern of the entirety of the inspected molded parts from the statistical data. This analysis allows trends to be detected at an early stage. As a result, they can be offset by introducing corrections to the process parameters of the manufacturing process at an early stage.

[0016] In particular, the evaluation and / or control of the manufacturing process can be carried out based on artificial intelligence or suitable algorithms. This allows for rapid adaptation to changed conditions, which is only possible conditionally in conventional parameterizable systems. This makes it possible to effectively detect even unpredictable errors and / or trends.

[0017] The lighting device can be designed to guide light directly and / or indirectly through the molded part, so that the camera can record at least one image of the molded part on the side of the molded part opposite the light source. Particularly suitable are light panels and the use of polarized light, diffusers or coaxial light. However, it is also possible to achieve a uniform illumination of the molded part by means of dome lighting, i.e. dome-shaped lighting, in particular polychromatic dome lighting, while avoiding reflections of the molded part located between the light source and the camera. Furthermore, it is also possible to use a plurality of light sources with different light properties, for example IR, UV and / or X-ray radiation.

[0018] According to the invention, test objects which can be produced as molded parts in upstream thermal or molding processes are optically inspected using the transmitted light method. These molded parts are in particular closures and / or lids or preforms and generally plastic containers. In particular, the inner regions of molded parts designed as closures can be inspected in backlight for various defects, from which process errors can be inferred.

[0019] Error points or defects can be inclusions, which may appear in the form of air pockets, foreign matter such as dust, dirt and / or metal particles, and prematurely solidified material. The included cooling material, also called cold plugs, occurs in particular in the area of ​​the injection point or casting point and is recognized as comet-like marks or locally concentrated schlieren in thin-walled or transparent molded parts. Air pockets that can be attributed to air trapped by the material melt will show different error images. What may occur here are error points caused by areas of unfilled material, bubbles, pinholes, pores, and / or dark spots on the surface of the molded part or in the case of transparent materials due to thermal damage. Air inclusions occur if the air in the molding die is not discharged quickly enough, for example when the ventilation channels are blocked. Based on the detectable inclusions, conclusions about the manufacturing process can be drawn.

[0020] In one embodiment of the invention, the entire surface of the molded part is optically inspected using the transmitted light method to find fault points and / or deviations. Of interest here are the areas of the pouring point or injection point that are difficult to inspect using the reflected light method.

[0021] In a further embodiment of the invention, the shaped parts are optically inspected along the production line using the transmitted light method to detect faults including color deviations, schlieren, holes and / or cracks, from which conclusions can be drawn about the production process of the shaped parts.

[0022] Color deviations can occur in particular after a color change of the material used (the so-called masterbatch). During the injection molding process, the old color can still be detected in or on the molded part after many cycles after the color change, which can usually be recognized along the production line. However, colored schlieren can also be caused by an uneven distribution of the pigment in the material. One of the causes of such colored schlieren can be the wear of the mold inserts known as "gate inserts." Especially in the case of the increasingly popular translucent colors, such colored schlieren are easily recognizable and lead to scrap. Replacing the mold inserts at an early stage can reduce scrap.

[0023] The appearance of Schlieren can have many manifestations and different causes. Water in different states of polymerization as a material component leads to cloud formation, watermarks and / or moisture Schlieren. This can be caused by the material being used absorbing water easily, too high a humidity level, too cold a mold wall, incorrect temperature at the material inlet. Water from leaky water cooling can also be identified by the error point. In addition, burn Schlieren can occur due to severe thermal damage of the material. This can be caused by thermal damage of the molten material due to oxidation and / or material decomposition due to strong friction. Incorrect ventilation can be inferred from this. Air Schlieren can also occur.

[0024] Other detectable errors may be shear marks caused by pulsating material flow, the so-called Diesel effect, gloss differences, etc.

[0025] Pores, in particular micropores, so-called pinholes, which can be detected as fault points indicate possible deposits in the area of ​​the injection point. These micropores have an influence on the tightness of the injection-molded closure and are an important quality criterion. Compared with the known methods for detecting micropores by high-pressure testing, the method according to the invention is significantly simplified. However, not only actual pores but also depressions can be detected.

[0026] The transmitted light method can also be used to detect cracks, such as microcracks and / or stress cracks. Stress cracks are internal and / or external cracks caused by local stresses.

[0027] Depressions on the molded part surface can also be detected by transmitted light inspection, as can domes, which are produced, for example, by unmelted material as deposits in the upstream hot channel.

[0028] If projections, ie burrs, are revealed during optical inspection of the molded part, it can be inferred that molten material has penetrated into gaps or seams at the mold parting lines and that these are therefore not sufficiently tightly closed.

[0029] In another embodiment of the invention, the optical inspection of the molded part is carried out using the transmitted light method to detect engravings, markings, etc., in particular on the top plate of the closure cap. The transmitted light method allows an almost reflection-free optical inspection under optimal lighting, so that the properties and quality of the molded part can be determined by image processing. In particular, the cavity number of the production mold, the so-called nest number, can be clearly identified by configuration. In addition, defects can be detected inside the closure part and on the opposite side, depending on the color of the molded part material.

[0030] Furthermore, according to one embodiment, the geometry of the molded part is checked during an optical inspection using a transmitted light method. In this case, functionally relevant areas, such as sealing elements and / or threaded areas, are of particular interest. Faulty points on the sealing element, such as cutouts or missing material, can render the closure unusable.

[0031] Detectable geometric deviations of the actual molded part from the ideal shape can include deformations, distortions, warping and / or angular deviations. Preferably, the wall thickness differences, which are essential for the sealing function, can be detected using transmitted light methods and thus almost without reflection.

[0032] In particular, the transmitted light method can be used to check for possible faults in the area of ​​the injection point. Preferably, when the molded part is optically checked using the transmitted light method, the geometry of the injection point, in particular the diameter of the injection point, is determined, which enables conclusions to be drawn about the manufacturing process. If possible, the injection point is positioned on the molded part so that the molten material enters the mold strategically and as evenly as possible. For rotationally symmetrical closures, the outside and inside of the closure must be coaxial in order to have a uniform wall thickness. Different wall thicknesses can have a negative impact on the tightness of the closure. Therefore, the position and / or shape of the injection point can be used as a quality criterion.

[0033] Another embodiment of the invention relates to the optical inspection of an object manufactured in a multi-piece forming mold using the transmitted light method. Even in the case of a forming mold in which the mold halves are precisely centered with respect to one another, so-called core shifts, i.e. core misalignment, may occur. In the case of unbalanced mold filling, the core may be displaced, which may lead to wall thickness deviations in the molded part. In particular, if the molded part is a closing cap, the core shift may lead to a relative displacement of the closing cap from the outside to the inside. Uneven wall thicknesses may have a negative impact on the tightness and / or represent weak points that affect functionality.

[0034] For various reasons, molded parts may deviate from the desired geometry, for example in terms of diameter and / or ovality or roundness as an example of geometrical defects. In a preferred embodiment, when optically checking the molded parts using the transmitted light method, the outer diameter of the molded parts is measured and correlated with the diameter of the inner sealing diameter. For example, based on the ratio that can be determined, the ovality of the sealing diameter of a rotationally symmetrical molded part (e.g. a closure cap) can be inferred, which has an influence on the tightness of a molded part that is designed as a screw closure. If this ratio is outside a definable tolerance, the process parameters are corrected or the molding tool is checked.

[0035] In a preferred embodiment of the invention, the method is designed to optically inspect the molded parts produced in the manufacturing process using the transmitted light method in accordance with the manufacturing process. In this case, the method according to the invention can make the inspection time required for its optical inspection follow the rhythm of the manufacturing process. Therefore, the method can be carried out at high speed or at a speed that is independent of the manufacturing process.

[0036] The invention also relates to a system for carrying out the method according to the invention. The system comprises a conveying device for moving the molded part along a conveying path to an inspection area for optical inspection using the transmitted light method. The conveying device is designed to guide the molded part smoothly past the recording device and avoid swinging movements or tilting postures. Here, the conveying device can have two driven and prestressed belts that rotate around a drive wheel and another wheel respectively, and the two belts define a conveying path between them. Here, the width of the conveying path can be slightly smaller than the free outer diameter of the molded part. Therefore, a smooth and damage-free guidance of the molded part can be achieved under sufficient clamping force and at a high conveying speed, wherein the molded part is guided in a torsion-proof manner and an unquestionable optical inspection can be carried out. Not only can the rotation speeds of the two belts be different from each other, but also the types of belts can be different. In addition, the number and type of drive wheels can be changed, and the drive wheels can also be prestressed by a correspondingly designed device. Alternatively, the conveying device can include one or more star wheels. The inspection area has a recording device and an illumination device, which are arranged so that the molded part is located between the recording device and the illumination device during recording. This can improve the recording quality, which ultimately allows for a better evaluation of the image.

[0037] Preferably, at least one illuminator is placed behind the projection surface or panel. The molded part is illuminated from behind relative to the camera. As a result, an optimal illumination of the molded part can be achieved during the optical inspection, so that various defects and / or flaws can be easily and accurately detected. In addition, the transmitted light method can be used in combination with the reflected light method, which has further advantages.

[0038] It should be reminded again that, in addition to the above-mentioned method for inspecting an object to be inspected using the transmitted light method according to the present invention, the present invention also relates to a corresponding system.

[0039] More details of the present invention will be given from the following description of preferred embodiments, which are exemplarily shown in the accompanying drawings. From this description, more advantages of the present invention can be understood, and opinions and suggestions on how to modify the subject matter of the present invention or on how to further develop within the scope of the requirements can also be understood. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram showing the inspection area for optical inspection of a molded part using the transmitted light method,

[0041] Figure 2 A flow chart of image processing for verifying defects is schematically shown;

[0042] Figure 3 A schematic diagram showing detectable defects using a closure as an example;

[0043] Figure 4 The core misalignment is shown using the closure as an example;

[0044] Figure 5 A schematic view of a conveyor device for inspecting molded parts using the transmitted light method is shown;

[0045] Figure 6 A schematic diagram of another conveying device is shown. DETAILED DESCRIPTION

[0046] exist Figure 1 Schematically shows an optical inspection area for optically inspecting a molded part 10 using a transmitted light method. The system 1 for optically inspecting a molded part 10 includes a conveying device (not shown) for conveying the molded part 10 along a conveying direction indicated by an arrow 2. In particular, Figure 1The molded part 10, which is shown as a closure cap in the example, can be passed through the optical inspection area in a defined direction and sequence. In particular, the molded parts 10 can be introduced separately into the optical inspection area, which can be done by a suitable conveying device. The closure part designed as a molded part 10 can be in the form of a cylindrical hollow body closed on one side, including a lower part with an internal thread and, if necessary, a protection band (garantieband) which is injection-molded onto the lower part via a tab. In addition, the molded part 10 can have one or more printed markings, which can be verified, for example, according to the invention.

[0047] At least one camera 20 is provided in the optical inspection area, which is designed to create at least one image of the molded part 10. As shown in the figure, the camera 20 can include a camera arranged above the molded part 10 and an optional filter element (not shown) so that its optical axis is parallel to the molded part axis 10a of the molded part 10 to be inspected. The optical axis of the camera extends approximately through the center of the rotationally symmetrical molded part 10. The lighting device 30 is arranged opposite to the camera 20 here to generate transmitted light. The transmitted light preferably extends in the direction of the camera 20 parallel to the optical axis. Therefore, the molded part 10 to be inspected is at least temporarily located between the camera 20 and the lighting device 30 in the optical inspection area. Therefore, the optical inspection can be performed using the so-called transmitted light method, which is more advantageous than using other methods. The transmitted light method is particularly suitable for imaging the molded part 10 passing through the optical inspection area without interfering reflections. For example, inclusions inside the molded part 10 can be detected, which will allow conclusions to be drawn about the manufacturing process of the molded part 10, such as an injection molding process. These detectable inclusions allow the process parameters to be changed after processing and evaluation and analysis in the processing unit (e.g. processor and other components). The processing unit is denoted by reference numeral 40 below, by which the image of the molded part captured is processed and evaluated for inspection, and the data is analyzed. Based on this, definable process parameters of the manufacturing process can be adjusted. The image captured by the camera 20 can be processed or analyzed accordingly by the image processing device in order to detect or determine various defects and statistical data in the molded part 10. For image evaluation or for statistical data evaluation, an algorithm can be used, which can be adjusted or selected accordingly depending on the molded part 10 to be inspected.

[0048] For the transmitted light method, the at least one lighting device 30 can be designed to achieve optimal illumination of the molded part 10 during the image acquisition, directly or indirectly. Thus, an illuminator can be arranged behind the projection surface or plate of the lighting device 30 in order to achieve optimal illumination without disturbing reflections on the molded part surface. Suitable are, for example, light panels and the use of polarized light, diffusers and / or coaxial light. In principle, it is conceivable to: Figure 1In addition to the lighting device 30 arranged in the illustration, further lighting devices can also be arranged which additionally or alternatively also allow an optical inspection of the molded part 10 using the incident light method.

[0049] exist Figure 2 The processing and analysis of the images recorded by recording device 20 are shown purely abstractly, so that the knowledge gained therefrom can be used to adjust the production process. Figure 2 Schematically shown in FIG. 4 is a processing device 40 for processing and evaluating images of molded parts 10. The processing device 40 comprises a processor 42, which processes the images captured by the recording device 20 or the various images captured in order to detect defects and / or collect and analyze statistical data from all images. For this purpose, the processor 42 may include an image processing device, which processes the captured images accordingly, which is necessary to be able to find defects and / or possible statistical deviations in the molded parts 10 (even defect-free molded parts). These defects can be, for example, air pockets, foreign bodies and / or inclusions in the form of solidified material, which can be detected in the interior and / or walls of the molded parts 10. In addition or alternatively, error points in the form of color deviations, schlieren, holes, depressions, burns, foreign bodies and / or cracks can also be determined. Possible engravings and / or markings can also be checked. As will be explained below, the area of ​​the injection point can be checked in particular, which is based on experience particularly prone to defects. An important defect or error is so-called core misalignment and different wall thicknesses, which can affect the tightness of the molded part 10 designed as a closure. Core misalignment, also called core shift, occurs when the mold halves are not aligned exactly with each other during the injection molding process. In the closure, this means that the outer side is not centered relative to the inner side. The formation of different wall thicknesses has a negative impact on the tightness.

[0050] For processing and evaluating the captured images, an analog-to-digital conversion may be required, for example. The processing device 40 therefore uses an algorithm, which can vary depending on the type of molded part 10. After a so-called preprocessing in the processing unit 44, which includes known image processing and statistical analysis using artificial intelligence or algorithms, the information obtained can be converted into control parameters or corrected process parameters for the manufacturing process. These determinable control parameters are subsequently transmitted to the controller 46 of the manufacturing process, which determines the process parameters in the transformation unit 48 based on these parameters. In other words, the process parameters of the manufacturing process or the injection molding machine are adjusted based on the data that can be determined by the processing unit 44. For this purpose, statistical data and / or real-time data are exchanged between the processing unit 44 and the controller 46 in order to be able to detect trends, patterns and / or accumulations of defects at an early stage. By timely adjustment of the process parameters or execution variables of the manufacturing process, this can be counteracted to avoid a greater amount of scrap. In Figure 3 The various defects to be detected are shown in the example of a molded part 10 designed as a closure. The molded part 10 has essentially the shape of a cylindrical hollow body which is closed on one side and can be provided as a screw closure for bottles. Closures of this type are manufactured in large quantities in a molding injection molding machine from plastics such as polyethylene, polypropylene or PET (polyethylene terephthalate). Figure 1 As shown in FIG. 1 , the molded part 10 is separated and transported to the optical inspection area in an orderly manner, that is, lying on its end face 14. In the cross-sectional side view of the molded part 10, the wall 12 can be seen, wherein a fault point 9 is shown in the closed end face 14. This may be a microcrack, which is only Figure 3 In addition, conclusions about the manufacturing process can be drawn from the appearance of the injection point 16. In the case of rotationally symmetrical molded parts 10, an injection point 16 that is not arranged centrally can be used to infer a core misalignment and, therefore, an incorrect positioning of the injection mold halves. The injection point 16 is the area where faults such as microcracks, micropores, etc. occur more frequently. Figure 3 As can be seen from the top view, both the injection points 16 and the schlieren 17, in particular the colored schlieren and / or the moisture schlieren and / or the air schlieren, as well as the depressions or markings in the form of so-called cavity numbers or nest numbers 15, are examples of errors or indications which can be well detected using the transmitted light method.

[0051] exist Figure 4 1 shows a core misalignment on a molded part 10 designed as a closed part. Here, the outer side 11 and the inner side 13 are not centered. This can be caused by a displacement of the core under the injection pressure and / or an asymmetrical injection of the injection material and / or pressure and / or temperature differences at the opposite mold walls. The displacement can also be caused by unclean installation of the mold halves and / or inaccurate mechanical settings. This can lead to uneven wall thicknesses. This is shown in FIG. Figure 4 This is represented by the misalignment between the axis 11 a corresponding to the outer side 11 and the axis 13 a corresponding to the inner side 13 .

[0052] Figure 5 It is schematically shown how the molded part 10 passes through the optical inspection area between the camera device 20 and the lighting device 30 in the conveying direction 2 and is inspected there using the transmitted light method. For this purpose, a conveying device 50 is provided, which allows the molded part 10 to be inspected or controlled to be transported. In the embodiment shown, the conveying device 50 can include two parallel conveyor belts 52, which act laterally on the molded part 10.

[0053] Figure 6A detailed view of a conveying device 50 configured as a star wheel 54 is schematically shown, which conveying device 50 can be considered to be combined with an optical inspection that can be performed using a transmitted light method. The star wheel 54 includes a plurality of fingers 55, which form pockets 56 between each other. The molded parts 10 can be continuously supplied by a conveyor belt (not shown) and engage with the pockets 56 of the star wheel 55. Therefore, the pockets 56 at least partially surround the molded parts 10. Optionally, the molded parts can be held in the pockets 56 by vacuum and inspected using transmitted light in the holding position. Subsequently, the molded parts 10 can be released from the pockets 56 respectively and can be sent to other stations. In the example shown, the star wheel 54 rotates counterclockwise at an adjustable speed.

[0054] Alternatively, the profiled element 10 can be slid on an at least partially transparent plate in order to be able to inspect the bottom area of ​​the profiled element 10 .

Claims

1. A method for optically inspecting a shaped part (10), in particular a closure part or the like, produced during the manufacturing process by a thermoforming or extrusion process, using transmitted light, the method comprising: - conveying the molded part (10) by a conveying device (50) through an optical inspection area, and - capturing at least one image of the molded part (10) by means of a camera (20), wherein the molded part (10) is located between the camera (20) and an illumination device (30) and is illuminated by the illumination device, The image is evaluated by a processing device (40) in order to determine defects and / or statistical data of the molded part (10), so that conclusions can be drawn about the manufacturing process of the molded part (10) in a molding mold having a cavity, which conclusions can be used to control the manufacturing process. The method for optically inspecting a molded part (10) according to claim 1, characterized in that the evaluation can use an adjustable algorithm.

2. The method for optically inspecting a molded part (10) according to claim 1, characterized in that Air pockets, foreign matter and / or inclusions in the form of solidified material can be detected.

3. Method for optically inspecting a molded part (10) according to claim 1 or 2, characterized in that An optical inspection of the molded part (10) using a transmitted light method is performed on the entire surface of the molded part (10).

4. Method for optically inspecting a molded part (10) according to any one of the preceding claims, characterized in that The molded parts (10) are optically inspected along the production line using the transmitted light method in order to detect fault points in the form of color deviations, schlieren (17), holes, recesses (15), burns, foreign bodies and / or cracks (9).

5. Method for optically inspecting a molded part (10) according to any one of the preceding claims, characterized in that Optical inspection using transmitted light can be used to detect the schlieren (17) after the material has changed color.

6. Method for optically inspecting a molded part (10) according to any one of the preceding claims, characterized in that The detectable schlieren (17) can be attributed to material properties, process temperature and / or an unsealed temperature control system of the forming tool.

7. The method for optically inspecting a molded part (10) according to claim 4, characterized in that The detectable depressions (15) and / or cavities are present in the form of micropores which can be attributed to deposits in the molding tool in the region of the injection point (16).

8. Method for optically inspecting a molded part (10) according to any one of the preceding claims, characterized in that The engraving and / or marking (15) of the molded part (10) can be detected and inspected by optical inspection using transmitted light.

9. Method for optically inspecting a molded part (10) according to any one of the preceding claims, characterized in that Optical inspection using transmitted light can be employed to determine the placement and shape of the injection points (16).

10. Method for optically inspecting a molded part (10) according to any one of the preceding claims, characterized in that Optical inspection using transmitted light can be used to inspect the uniformity of the wall thickness of the molded part (10) and / or the core misalignment.

11. Method for optically inspecting a molded part (10) according to any one of the preceding claims, characterized in that Optical inspection using transmitted light can be used to detect ovality and / or other geometrical defects of the molded part (10).

12. Method for optically inspecting a molded part (10) according to any one of the preceding claims, characterized in that The optical inspection using the transmitted light method can be performed in combination with the incident light method and / or can be performed in parallel with the manufacturing process of the molded part (10).

13. A system for optically inspecting a molded part (10) according to the method of any one of the preceding claims, comprising: a conveying device (50) for conveying the molded part (10) into an optical inspection area; A camera device (20) for creating an image of the molded part (10); a processing device (40) to which the image can be transmitted for inspection; and an illumination device (30), the system being used for inspecting the molded part (10) using a transmitted light method during optical inspection, characterized in that defects and / or statistical data of the molded part (10) can be determined.

14. System for optically inspecting molded parts (10) according to claim 13, characterized in that The lighting device (30) is arranged to directly or indirectly illuminate the molded part (10) when capturing an image.

15. System for optically inspecting molded parts (10) according to claim 13 or 14, characterized in that The molded parts (10) are conveyed into the optical inspection area while being guided by side belts (52) or by star wheels (54).

Images