HK1064991A - Part-forming machine having an in-mold integrated vision system and method therefor - Google Patents

Description

Part forming machine with in-mold integrated vision system and method of using same

Technical Field

The present invention relates generally to part forming machines, and more particularly to a part forming machine with an integrated vision system in the mold and method of use thereof.

Background

The part forming industry is one of the largest industries in the world, both in overall value and in number of workers. Even small improvements to the manufacturing process can result in significant efficiencies and economies because of the production values above tens of millions of dollars. To this end, various methods and machines for forming parts have been proposed. For example, parts are generally formed by a mold, a cast mold and/or a thermoforming method, wherein molds are widely used at present, and many methods for forming parts by molds are known at present, such as stretch blow molding, extrusion blow molding, injection blow molding, vacuum molding, rotational molding and injection molding, to name a few.

One conventional method of manufacturing hollow containers is by a widely used method known as stretch blow molding, wherein a three-piece mold is typically utilized having two opposing side members and a bottom/male mold. An injection molded preform (also called a parison), generally shaped like a test tube, is typically inserted into the top of the mold. A rod is then inserted into the parison, with which the parison is extended to the bottom of the mold, and with which compressed air is admitted into the parison, thereby stretching it outwardly, first towards the vicinity of the centre of the side mold parts and then over the male/bottom mold. The parison is generally amorphous prior to the start of the blow molding process, however after stretching the parison, the molecules align to form a container with very high tensile strength.

A more common method is to form the part using a process known as injection molding. Injection molding systems are commonly used to mold plastic parts and certain metal parts by forcing a liquid or molten plastic or powdered metal in a plastic binder matrix into a specially shaped mold cavity of a mold, where the plastic or plastic binder matrix is cooled and allowed to solidify to form a solid part. For convenience, references herein to plastic and plastic injection molds should be understood to apply equally to injection molding of powder metal and other materials that may be injection molded into parts, even if not specifically mentioned or stated in the description.

A typical injection mold is generally formed as two separate parts or halves that are shaped to form the desired inner mold cavity or cavities when the two halves are mated or secured together. The one or more parts may then be removed from the one or more inner mould cavities by separating the mould halves to expose the one or more solidified plastic parts after the liquid or molten plastic has been injected into the mould to fill the inner mould cavity or cavities and subsequently allowed to cool or solidify to form a rigid plastic part or parts depending on the number of mould cavities.

In many automated injection molding systems, a mold ejector is provided to remove or push the cured plastic part out of the mold cavity. Typical stripping apparatus include one or more elongated stripping bars that extend through a mold half into a mold cavity or cavities and an actuator connected to the bar or bars to slide the bars longitudinally into or into the mold cavity or cavities to push the solidified part or parts out of the mold cavity or cavities. However, other types of stripping means, such as a robot, scraper or other means, may be used. These stripping devices are generally very effective in pushing the cured plastic part out of the mold cavity, but they do not prevent erroneous operation. It happens that the solidified plastic part adheres or hangs in the mould cavity, although the stripping means have been driven. A very common method is to have the stripping means driven or stroked several times in rapid succession, for example four or five times when it is desired to remove a cured plastic part, so that the part may be pushed out in one or more subsequent strokes or ejections of the stripping means if the part is still attached or not pushed out of the mould cavity when it is first stroked by the stripping means. Such multiple operations of the mold-stripping apparatus are generally effective in ejecting or extracting the cured molded plastic part from the mold. However, such multiple operation of the ejector has the disadvantage that additional time is required for the multiple operation of the ejector from the time the mold is opened to eject the cured plastic part to the time the mold is closed for injection of the next part, and also has the disadvantage that additional wear and tear will be caused to the ejector and the mold due to such multiple ejection operations. On a repeated high-throughput production line, this extra time, as well as this wear and tear, during the day, week and month injection molding process, can significantly impact throughput and production costs.

On the other hand, a cured plastic part that is adhered or not completely removed may also cause significant damage to the mold and lost production time. In most injection mold lines, injection molding machines are automated and once loaded with the desired mold, they continue to repeat the process of closing the mold halves together, heating the mold, injecting liquid or molten plastic into the mold cavity, cooling and solidifying the plastic in the mold cavity to form a solidified plastic part, then opening or separating the mold halves, ejecting the molded solidified plastic part, and finally re-closing the mold halves together to mold another part or set of parts. In order to inject liquid or molten plastic into the mold cavity so that it completely fills all portions of the mold cavity in a timely manner, high injection pressures are typically required which tend to separate the mold halves as the plastic is injected. To prevent this separation of the mold halves during injection of the plastic, many injection molding machines are equipped with powerful mechanical or hydraulic actuation devices to hold the mold halves firmly together. If the cured plastic part of a previous cycle of operation is not taken up and not completely removed from between the mold halves, a powerful mechanical or hydraulic actuating device will close the mold halves onto the cured plastic part, which may and often does result in damage to one or both of the mold halves. Molds are typically made from stainless steel or other hard metals with high precision machining, so they are costly to replace and require downtime to replace, which also increases labor and production costs. It is also sometimes the case that some plastic parts may break in the mould cavity and separate from the rest of the moulded part in the mould cavity, which remains in the mould cavity when the rest of the moulded part is pushed out. This residual material will prevent the mold cavity from being properly filled and the next part from being molded, causing the subsequently molded part to become scrap. In an automated manufacturing line, a large number of such waste parts may be produced before one finds such residual material, taking the injection molding machine to a standstill, eliminating the problem.

In order to avoid such mold damage, downtime and molding of rejected parts, various techniques have been proposed and applied to detect or determine whether the cured molded plastic part has indeed been completely ejected or removed from the mold prior to having mechanical or hydraulic actuation means close the mold halves. Such techniques include beam sensors, vision systems, air pressure sensors, vacuum sensors, and other devices. U.S. patent No.4841364 to Kosaka et al is an example of a vision system in which a camera connected to a camera system controller captures a view of the open mold halves for comparison with a view of the empty mold halves stored in memory to detect any plastic parts or residual plastic that have not been ejected from the mold halves. U.S. patent No.4236181 to Shibata, in which a light sensor is provided on a panel of a cathode ray oscilloscope so that it can be detected whether or not a component has been excluded, is also an example of an observation system.

As an improvement of the system, U.S. patent No.5928578 to Kachnic et al provides a rollover ejector system for an injection molding machine, wherein such system includes a vision system for taking actual images of an open mold after operation of the ejector and a controller for comparing such actual images with ideal images of the open mold to determine whether a part remains within the mold. If the part is still in the mold, the controller outputs a mold-stripping signal to drive the mold-stripping device to operate again. In addition, Kachnic et al, Kosaka et al and Shidata provide a means of detecting component defects.

However, the system is disadvantageous in view of the present systems and methods. Specifically, the system generally employs a CCD camera (charge coupled device camera) which is disposed on the top or both sides of the mold and takes an image of the mold. This requires the mold to be fully opened prior to imaging, thus prolonging the monitoring process time. In addition, since the sensing device forms an angle with the mold, the resulting image is oblique, thereby reducing the resolution of the image and increasing monitoring errors.

It is therefore readily seen that there is a need for a part forming machine having an in-mold integrated image sensor and method that provides images taken from the sensor at relatively parallel angles and thereby can provide more accurate inspection resolution. It is therefore an object of the present invention to provide such an improvement.

Disclosure of Invention

In accordance with a broad aspect and broad interpretation of the present invention, the present invention is a part-forming machine having an in-mold integrated image sensor and a method of identifying the presence, absence and quality of molded parts.

It is, therefore, a feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that can acquire images of the mold and/or part at relatively parallel angles to determine the presence, absence and/or quality of the molded part.

It is a further feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that captures images of the mold and/or part at relatively parallel angles, thereby eliminating oblique images, reducing the viewing area of individual pixels, and increasing the resolution of the image.

It is another feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that can acquire images of the mold and/or part at relatively parallel angles and that reduces the number of supplemental draw and/or supplemental validation times of prior systems.

It is another feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that can acquire images of the mold and/or part at relatively parallel angles, thereby increasing the accuracy of the image inspection system and increasing the efficiency of the part-forming process.

It is another feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that can acquire images of the mold and/or part at relatively parallel angles, thus increasing the resolution of the images and allowing the vision system to analyze tighter tolerances for process variations, thereby improving the vision system and the molding process.

It is another feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that can acquire images of the mold and/or part at relatively parallel angles and provide a light source that can be utilized at relatively parallel angles, thereby increasing the uniformity of illumination and allowing clearer images to be obtained.

It is another feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that captures images of the mold and/or part at relatively parallel angles, thereby capturing images before the mold is fully opened, thus increasing the speed of operation of the part-forming machine.

It is another feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that can acquire images of the mold and/or part at relatively parallel angles, wherein the images are transmitted to the sensor using a coherent fiber optic bundle or cable.

It is another feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that can acquire images of the mold and/or part at relatively parallel angles, wherein an illumination source illuminates the mold and/or part via a fiber optic cable or bundle.

Another feature and advantage of the present invention is to provide a new and improved part-forming machine having an in-mold integrated image sensor that captures images of the mold and/or part at relatively parallel angles, thereby allowing the image to be taken before the mold is fully opened, and also to eject the part during the opening process and take the image immediately thereafter.

It is another feature and advantage of the present invention to provide a new and improved part-forming machine having an in-mold integrated image sensor that captures images of the mold and/or part at relatively parallel angles, thereby allowing the sensing device to focus on the image faster than when viewed obliquely.

It is another feature and advantage of the present invention to provide a new and improved method for determining the presence, absence and quality of molded parts in a part-forming machine that utilizes an image sensor within the mold to acquire images of the mold and/or part at relatively parallel angles.

It is another feature and advantage of the present invention to provide a new and improved method for determining the presence, absence and quality of molded parts in a part-forming machine that utilizes sensors within the mold; this process is more efficient and accurate than prior art methods.

It is another feature and advantage of the present invention to provide a new and improved method for determining the presence, absence and quality of molded parts in a part-forming machine that utilizes in-mold sensors whereby images can be taken during the mold opening process.

It is another feature and advantage of the present invention to provide a new and improved method for determining the presence, absence and quality of molded parts in a part-forming machine that utilizes in-mold sensors to capture images in relatively parallel positions, thereby allowing faster focusing or inspection of the part and/or mold.

These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from a reading of the following specification and claims with reference to the accompanying drawings.

Drawings

The present invention may be further understood by reading the detailed description of the preferred and alternative embodiments with reference to the drawings, in which like numerals indicate like elements and like parts throughout, and in which:

FIG. 1 is a perspective view of a typical prior art injection molding machine having a camera inspection system mounted on the top of the mold;

FIG. 2 is a partial cross-sectional side view of the injection molding machine of FIG. 1 with the ejector in a retracted position;

FIG. 3 is a partial cross-sectional side view of the injection molding machine of FIG. 1 with the ejector in an extended position;

FIG. 4 is a schematic logic flow diagram of a prior art system known as a rollover stripping system;

FIG. 5 is a functional block diagram of a controller of a prior art system known as a tumble stripping system;

FIG. 6 is a functional block diagram of a prior art component formation controller and analysis apparatus;

FIG. 7 is a partial perspective view of a preferred embodiment of the present invention;

FIG. 8 is a control function block diagram of a part shaping machine controller and analysis apparatus in accordance with a preferred embodiment of the present invention;

FIG. 9 is a plan view of a representative pixel grid area of a prior art imaging system, illustrating the effect of oblique viewing on pixel area;

fig. 10 is a plan view of a representative pixel grid area of the present invention, showing the reduction in viewing area of individual pixels.

Detailed Description

In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology is employed for the sake of clarity. The invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents which operate in a similar manner to accomplish a similar function.

For all of the embodiments described herein, it should be appreciated that alternative features may be formed in connection with the present invention, including aesthetically pleasing coatings and surface designs as well as labels and tags manufactured, but not limited to, such features, without departing from the scope of the present invention.

For a better understanding of the system and method of the present invention, it is advantageous to first understand the basic knowledge of a typical prior art injection molding machine and process. Thus, and with initial reference to FIGS. 1-3, a conventional automatic injection molding machine 10 is shown which is equipped with a mold 12 comprising two mold halves 14 and 16, a slide lift system 18 and a camera 20 which electronically captures a visual image of the open mold half 14 which can be digitally stored in memory and processed so that the presence or absence of a plastic part or object in the mold half 14 can be determined.

In general, the exemplary conventional injection molding machine 10 includes two platens 24, 26 mounted on a frame of 4 long, relatively large support columns 28, 30, 32 and 34 for mounting the mold halves 14 and 16 of the mold 12. The fixed platen 24 is fixedly secured to the posts 28, 30, 32 and 34, and the movable platen 26 is slidably mounted on the posts 28, 30, 32 and 34 such that the platen can move back and forth relative to the fixed platen 24 in the direction indicated by arrow 36. Thus, the mold half 16 mounted on the movable platen 26 may also be moved in the direction indicated by arrow 36 relative to the other mold half 14 mounted on the fixed platen 24. A large axial force can be applied by a large hydraulic or mechanical actuator 38 connected to the movable platen 26 to move the mold half 16 into contact with the mold half 14 and to bring the mold halves into close engagement when the liquid or molten plastic 40 is injected into the mold 12, as best shown in fig. 2. Most dies 12 also include internal tubes 15 and 17 that flow heating and cooling fluids, such as hot and cold water, through the respective die halves 14 and 16. Cooling fluid delivery hoses 19 and 21 connect the respective tubes 15 and 17 to a fluid source and pump system (not shown). Typically, a high temperature fluid is required to flow through the tubes 15 and 17 to maintain the mold 12 at an elevated temperature during the injection of the liquid and molten plastic 40 into the mold cavity 50. Cooling fluid is then passed through the tubes 15 and 17 to cool the mold 12 and solidify the liquid or molten plastic into a hardened plastic part 22 as shown in fig. 3. A typical plastic injection or extrusion system 42 includes an injection tube 44 and an auger 45 within the tube 44 that forces the liquid or molten plastic 40 through an aperture 46 in the stationary platen 24 and a tube 48 in the mold half 14 into a mold cavity 50 formed or machined in the mold half 16. In many applications, there may be more than one cavity in the mold 12 for a single molding operation. In such multi-cavity molds, multiple lifters are required to push the cured molded part out of all of the cavities. The plastic extrusion system 42 further includes a hopper and/or funnel 52 for filling the tube 44 with granular solid plastic 41, heating coils 47 or other heating system disposed about the circumference of the tube 44 for heating the granular plastic 41 sufficiently to melt the granular plastic 41 into liquid or molten plastic 40 in the tube 44, and a motor 54 for driving the auger 46.

After the liquid or molten plastic 40 is injected into the mold 12 to fill the mold cavity 50, as shown in fig. 2, and the plastic 40 in the mold cavity solidifies as described above, the actuator 38 is actuated to separate the mold halves 16 and 14 so that the solidified plastic part 22 can be ejected from the mold cavity 50. Once mold halves 14 and 16 are fully separated, part-forming machine controller 72 will send a signal to camera 20 to take a first image of mold half 16 and then analyze the image to ensure that part 22 is present in mold half 16. The cured plastic part 22 is then ejected using the more efficient mechanisms or methods of the present invention as described above, and the ejection system 18 shown in fig. 1-3 is merely one example for the purpose of illustrating the present invention. The ejector system 18 includes two sliding ejector pins 56 and 58 that pass through the movable platen 26 and the mold half 16 into the mold cavity 50. When the mold 12 is closed as shown in fig. 2 to fill the mold cavity 50 with plastic 40, the ejector pins 56 and 58 extend only into the mold, but do not enter the mold cavity. However, when the mold is opened, as shown in FIG. 3, the ejector actuator 60, which includes two small hydraulic cylinders 62 and 66 and a crossbar 68 connected to the ejector pins 56 and 58, pushes the ejector pins 56 and 58 into the mold cavity 50 and pushes the hardened plastic part 22 out of the mold cavity 50. Because the ejector pins 56 and 58 accidentally do not fully eject the hardened plastic part 22 out of the mold cavity 50 by just one stroke or ejection, it is common practice to cycle the ejector driver 60 several times so that the ejector pins 56 and 58 repeatedly move back and forth into and out of the mold cavity 50 so that if the cured plastic part 22 remains in the mold cavity, it will be impacted and ejected several times, thus minimizing the inability to fully eject the cured plastic part 22. The part-forming controller 72 then sends a signal to the camera 20 to take an image of the mold half 16 containing the mold cavity 50, which is then electronically transferred to an image processing system where it is digitized and compared with a computer or microprocessor to an ideal image of the mold half 16 and the empty mold cavity 50. If the comparison of the images shows that the mold cavity 50 is empty and the cured plastic part 22 has been removed from the mold half 16, the actuator 38 is actuated to close the mold 12 and begin the next molding operation. On the other hand, if the comparison of the images indicates that the cured plastic part 22 has not been removed from the mold cavity 50 or has not been removed from the mold halves 16, the actuator 38 is not allowed to close the mold 12 and a signal is generated alerting the operator to inspect the mold, expel any residual plastic or cured plastic part 22 from the mold cavity 50 and the mold 12, and then actuate the plastic injection molding machine 10.

As described above, the repeated operation of ejector pins 56 and 58 that is enabled in some conventional injection molding systems can reduce the incidence of solidified plastic part 22 not being ejected from the mold cavity or removed from mold half 16. However, in many cases, the solidified plastic part can be completely removed when ejector pins 56 and 58 are only stroked and ejected once, which is far more frequent than the need for additional stroking and ejection with ejector pins 56 and 58, and repeated operation of ejector system 18 each time mold 12 is opened takes more time and causes unnecessary wear and tear on ejector system 18 and mold 12. As a modification, a tumble stripping system such as that described in U.S. patent No.5928578 to Kachnic et al is commonly used, in which the stripping system 18 is driven only when required. For example, rather than having the ejector pins 56 and 58 impact or operate fixed a large number of times each time the mold 12 is opened in a plastic part molding operation, the ejector pins 56 and 58 are impacted a variable number of times to achieve the ejection requirements of the respective molding operation. The repeated impact operations depend on the image of the mold 12 taken by the camera 20.

In a preferred embodiment of the present invention, as shown in fig. 7-8, the sensing system 300 includes an image capture source 310, a coupling member 320, a sensing device 330, and an analyzing device 340, wherein the analyzing device 340 is preferably a computer or microprocessor. Image capture source 310 is preferably disposed in the center of mold half 14, opposite the surface of mold half 16, such that mold half 16 and any components thereon generally form a nearly uniform angle with respect to image capture source 310. It should be noted, however, that in alternative embodiments, the image capture source 310 may be disposed at various locations in the mold such that various components or particular regions of the components may be imaged at substantially uniform angles. It should also be noted that any number of image capture sources 310 may be configured at different locations within the mold to increase resolution and/or improve the image analysis process. Image capture source 310 is preferably a coherent fiber optic bundle into which light waves and/or radiation can be captured and transmitted to sensing device 330 via coupling component 320. The connecting member 320 is preferably also a coherent fiber optic bundle that allows the sensing device 330 to see an image of the mold half 16 and/or member 22 at a distance, thereby preventing exposure of the sensing device to the elevated temperatures of the mold. The sensing device 330 is preferably located outside of the mold half 14, however in alternative embodiments the sensing device may be located at a more remote location or within one of the mold halves 14 and 16 remote from the part forming area, in a lower temperature zone, so that the sensing device 330 is not subjected to high temperatures. It should also be noted that the sensing device 330 can be thermally insulated and/or equipped with various known heat removal systems to protect the sensing device 330 so that it can be disposed within a mold.

The sensing device 330 is preferably a CCD array electronic camera. However, in alternate embodiments, the sensing device 330 can be any sensing device, such as, by way of example only, an infrared camera and a near infrared camera or an infrared thermal sensor.

In the preferred embodiment, analyzing device 340 receives electronic information from the image taken by sensing device 330 and analyzes the image to transmit information to part-forming machine controller 72 as to the presence or absence of a molded part in mold 12. If the parameters are known, the technician may present software that analyzes the image of mold 12. The analyzing device 340 is preferably integrated with the part-forming machine controller 72; however, a separate controller/computer in communication with the part-forming controller 72 may also be employed.

Because image capture sources 310 are arranged substantially in parallel, the first image may be captured immediately while mold 12 is opening, rather than waiting for part-forming controller 72 to signal that mold 12 has been fully opened, as long as sensing device 330 receives a signal from part-forming controller 72 that mold opening has begun. The image is then analyzed to ensure that the part 22 is present on the moving-side mold half 16; in response, the analyzing device 340 sends a signal to the part-forming machine controller 72. The first operation of the ejector pins 56 and 58 is then performed. This step may be performed while the mold 12 is opening. A second image is then taken and analyzed to determine that part 22 is not present on mold half 16, at which point if part 22 remains on mold half 16, another series of pin 56 and 58 operations are performed, depending on the number of operations that have been performed, or an alarm is activated to indicate to the operator that the part is still attached. If the second image indicates the absence of the part 22, the analysis device 340 sends a signal to the part-forming machine controller 72 to close the mold 12 and begin the next forming process.

Specifically, in the first state shown in FIG. 4, the analyzing device 340 transmits a signal to close the mold to the injection molding machine 10 through the part-forming controller 72 or any other data communication device. In response to such a signal, a closing/opening mechanism comprising an actuator will drive the actuator 38 to close the mold halves 16 and 14 to bring the mold halves together, and subsequently drive the plastic extrusion system 42 to inject the liquid and molten plastic into the mold 12 to form the plastic part, which after sufficient time to harden the plastic part, the process moves along arrow 76 to state B where the actuator 38 is driven to separate the mold halves 16 and 14. While the mold 12 is opening as shown in state B, the sensing device 330 captures an image of the open mold half 16 via the image capture source 310 and transmits the image via a cable or any other known transmission device to the analyzing device 340, which compares the image to an ideal image of the mold half 16 that would appear to be the presence of a fully formed plastic part 22 in the mold cavity. This comparison by the analysis device 340 is illustrated in FIG. 4 by decision block 80. At this point in the procedure, there should be a fully formed hardened plastic part 22 in the mold half 16. If the comparison of decision block 80 indicates that no plastic part 22 is present in the mold half 16, or that the plastic part 22 is present, but not complete, the analysis device 340 will terminate the procedure and signal an alarm 82 or other device, in the direction indicated by arrow 84, to notify the operator 86 to inspect the injection molding machine 10. However, if the comparison shows that there is a fully formed plastic part 22 on the mold half 16 as intended, the analysis device 340 will cause the process to proceed in the direction indicated by arrow 88 to state C by sending a signal through the injection molding controller 72 to cause it to drive the ejector system 18 to operate the ejector pins 56 and 58 once to impact or push the hardened plastic part 22 to push it out of the mold half 16. However, as described above, one extension of ejector rods 56 and 58 may accidentally fail to clear hardened plastic part 22 from mold half 16, and thus analysis device 340 will enter state D in the direction of arrow 90.

In state D, the analyzing device 340 takes another image of the mold half 16, which is captured by the sensing device 330 via the image capture source 310 and conveyed via the cable 78 or any other known conveying device, and compares this image, as represented by decision block 92, with an ideal image of the mold half 16 stored in memory, which is indicative of the cured plastic part 22 having been removed from the mold cavity, which mold cavity 50 is empty (not shown in fig. 4). If the comparison of decision block 92 indicates that the part 22 has been ejected and the mold cavity 50 is empty, the analysis device 340 continues the process to state A as indicated by arrow 94 by sending a signal through the injection molding machine controller 72 to actuate the actuator 38 to reclose the mold 12 and to actuate the extrusion system 42 to fill the mold 12 with plastic. On the other hand, if the comparison of decision block 92 indicates that the part 22 is still attached to the mold half 16, as indicated by dashed line 22', or that the part 22 has not been ejected, the analysis device 340 proceeds in the direction of arrow 96 to check the number of times the ejector pins 56 and 58 have been extended or operated. If the number of operations of the ejector pins 56 and 58 has been greater than the prescribed number, e.g., 5, as represented by decision block 98, and the part 22 has not been successfully ejected from the mold half 16, the analysis device 340 terminates the process and signals the alarm 82 or other device 86 as represented by arrow 100 to alert the operator. However, if the number of extensions has not exceeded a predetermined number, e.g., 5, the analysis device 340 returns the program in the direction of arrow 102 back to state C by notifying the ejector driver via the injection molding machine controller 72 to cause the ejector pins 56 and 58 to operate once more to impact and eject the part 22 once more. Analysis device 340 then proceeds in the direction of arrow 90 to state D, where sensing device 330 will take another image of mold half 16 and re-compare this image to the ideal image at decision block 92, which should be indicative of the part being ejected from mold half 16. If the part has been successfully removed during the last extension or operation of the ejector pins 56 and 58, the program proceeds to state A along arrow 94. However, if the comparison at decision block 92 indicates that the part 22' is still attached and not removed, then the analysis means 340 checks the number of operations at decision block 98, and if the number is not greater than a specified number, e.g., 5, then the analysis means 340 will return the program to state C again. The maximum number of operations set at decision block 98 may be any number, but is preferably set at a value such as 5, which is sufficient to cycle the ejector pins 56 and 58 for a good reason to say that such a number should be excluded from the part 22 without actually becoming useless. Thus, the ejector pins 56 and 58 can be extended or retracted in multiple cycles as part 22 is being attached, but the present invention prevents the unwanted repeated operation of the ejector pins 56 and 58 once part 22 has been removed from the mold.

As previously described and shown in FIG. 9, the prior art method of placing the vision system on top of the mold causes the vision to be skewed because the angle of the target relative to the camera is increased. Thus resulting in a larger viewing area for each pixel 400 and thus reduced image resolution, whereas in the present invention, as shown in fig. 10, the sensor or camera is held at a relatively parallel angle to the target, so that the viewing area 410 for each pixel is smaller and the image is more uniform and thus has higher resolution. As a result, more accurate analysis can be performed by the higher resolution image.

In a preferred embodiment, the sensing device has an illumination source that can be transmitted through connecting device 320 to image capture source 310, thereby directly illuminating part 22 and/or mold 12 at a substantially uniform angle. As a result, the target region can be illuminated more uniformly, thereby increasing the sharpness and accuracy of the captured image. In alternative embodiments, it can be seen that the illumination sources may be separately configured, they may be configured in-line with the sensing device 330, or the illumination sources themselves may be independent.

It should be noted that although the in-mold sensing system has been described in connection with a roll-over draw system, such in-mold sensing system may be used on any part forming machine. It should also be noted that any number of sensing devices 330 and/or image capture sources 310 may be employed.

Although the exemplary embodiments of the present invention have been set forth, it should be noted by those skilled in the art that these embodiments are merely illustrative and various other substitutions, modifications and changes may be made within the scope of the present invention. It is therefore intended that the invention not be limited to the particular embodiments disclosed in the specification, but be defined only by the claims which follow.

Claims (20)

1. A machine for forming parts, comprising:

a mold;

means for lifting at least one part out of the mold:

means for controlling said stripping means;

at least one sensor disposed within the mold, the sensor being visible at a substantially uniform angle to the mold, wherein a part formed by the machine is imageable with the sensor;

means for analyzing the image taken by said sensor, said analyzing means producing an indication of the presence, absence or quality of the at least one component, said analyzing means being in communication with said stripping means, wherein said stripping means is responsive to said indication.

2. Machine as claimed in claim 1, characterized in that said stripping means are at least one actuating means.

3. The machine of claim 1 wherein said means for controlling said stripping means is a programmable computer.

4. The machine of claim 1, wherein said analysis means is a programmable computer.

5. The machine of claim 1, wherein said analysis means is a programmable microprocessor.

6. The machine of claim 1, wherein said sensor is at least one ccd camera.

7. The machine of claim 1, wherein said sensor is at least one infrared sensor.

8. The machine of claim 7, wherein said infrared sensor is at least one infrared camera.

9. A machine for forming parts, comprising:

a mold having an interior and an exterior;

a stripping device for stripping at least one part out of the mould;

means for controlling said stripping means;

means for capturing an image, said means for capturing an image being disposed within said interior of said mold, said image capturing means being capable of viewing said mold at a substantially uniform angle, wherein said image capturing means is capable of capturing an image of a part formed by said machine;

a sensing device in communication with the image capture device;

means for transferring said image from said image capture means to said sensing means;

means for analyzing the image captured by said sensing means, said analyzing means being in communication with said sensing means, said analyzing means producing an indication of the presence, absence or quality of the at least one component, said analyzing means being in communication with said stripping means, wherein said stripping means is responsive to said indication.

10. The machine of claim 9, wherein said image capture device is at least one fiber optic bundle.

11. The machine of claim 9, wherein said image capture device is at least one lens.

12. Machine as claimed in claim 9, characterized in that said stripping means are at least one actuating means.

13. The machine of claim 9 wherein said means for controlling said stripping means is a programmable microprocessor.

14. The machine of claim 9 wherein said analysis means is a programmable microprocessor.

15. The machine of claim 9, wherein said sensor is at least one ccd camera.

16. The machine of claim 9, wherein said sensor is at least one infrared sensor.

17. The machine of claim 15, wherein said infrared sensor is at least one infrared camera.

18. The machine of claim 9, wherein said transport means is at least one fiber optic bundle.

19. A method for indicating the presence, absence and quality of a part in a part-forming machine, the method comprising the steps of:

a. capturing an image of the part at a relatively parallel angle;

b. transmitting the image to an image analyzer;

c. analyzing the image;

d. transmitting a signal to a part-forming controller, wherein said part-forming controller is responsive to said signal from said image analyzer.

20. The method of claim 19, wherein the step a. of capturing images of the part at relatively parallel angles is performed while the mold is opening.