Defect Detection of Extrusion Strip

Abstract

Defect detection systems and methods for detecting the presence of defects in an extrusion strip can include a variety of elements. In multiple examples, thermal imaging sensors have been used to detect a plurality of surface temperatures of the surface of the extrusion strip. A processing unit is configured to generate a thermal map of an area of the surface of the extrusion strip. The processing unit is further configured to determine whether a plurality of surface temperatures are outside of an acceptable tolerance range, which indicates the presence of a defect in the extrusion strip. Detecting defects during the extrusion process can help achieve the goal of reducing manufacturing waste and improving quality control.

Description

Background Art

[0001] Extrusion strips such as extrusion cap strips are often used for the construction of tire assemblies for automobiles and other vehicles. The process of manufacturing an extrusion cap strip requires the bonding of a rubber material and a plurality of cords. The rubber material is typically formed as a layer of uniform thickness that surrounds the plurality of cords, and the cords are typically linearly connected. When the rubber material is too thin or too thick, or when the cords are no longer connected when bonded to the rubber material, there may be defects in the extrusion cap strip.

[0002] Previous approaches for detecting defects in extrusion cap strips include the use of general-purpose 2D cameras for detecting surface contrast, 3D cameras for detecting surface structure, sensors attached to spools that supply the plurality of cords for detecting the rotation of the spools, sensors attached to spools of the plurality of cords for detecting that the cords are broken, or X-ray devices for detecting internal structure and defects. These previous defect detection systems have several drawbacks. For example, such systems may not be able to detect that the cords are broken, except when the cords are made of a metallic material or a specific color. Or, such systems may not be able to detect that the rubber material is chipped. Additionally, such systems may be limited by significant implementation costs or operating costs or health hazards. The embodiments described in the present application address these drawbacks.

Summary of the Invention

[0003] The embodiments described herein can be better understood with reference to the following drawings and description. The components of the drawings are not necessarily to scale.

Brief Description of the Drawings

[0004]

Figure 1

Figure 2

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0005] The following describes various aspects with reference to the drawings, in which like elements are generally identified by like numerals. The relationships and functions of the various elements of the aspects can be better understood by referring to the following detailed description. However, the aspects are not limited to those shown in the drawings or explicitly described below, and the patent claims and subject matter described herein include equivalent and specific subject matter. The drawings are not necessarily to scale, and in some cases, details not necessary for understanding the aspects described herein, such as conventional manufacturing and assembly, are omitted.

[0006] FIGS. 1 and 2 show various features and aspects of the defect detection system 100. FIG. 1 shows a side view of a part of the defect detection system 100. FIG. 2 shows a top view of a part of the defect detection system 100. The extrusion strip 102 may be, for example, a tire cap strip. The tire cap strip is used in the production of tires for automobiles or other vehicles, can improve the efficiency of the production process, and can impart strength to the tires. The defect detection system 100 can be used to detect defects in the extrusion strip 102 resulting from abnormalities in the manufacturing process. As an example, the present disclosure describes the tire cap strip. The system 100 can also detect defects in any other similar strip material (e.g., the material of the extrusion strip).

[0007] As shown in FIGS. 1 and 2, in an example of a manufacturing system, the extrusion strip typically moves from right to left. The drive mechanism 114 rotates clockwise as shown in FIG. 1, pulls the extrusion strip 102, and may store the extrusion strip 102 or move the extrusion strip 102 to the next step in the manufacturing process.

[0008] The extrusion strip 102 is formed by bonding a rubber material 106 and a plurality of cords 104, and the cords 104 are made of a material different from the rubber material 106 (for example, a metal material, a polymer material, etc.). In particular, strips made of other materials (for example, other than rubber and / or metal) are also conceivable, but for the sake of explanation, the rubber material 106 will be described throughout this specification.

[0009] As shown in FIG. 2, the plurality of cords 104 can be separated at substantially uniform distances, but non-uniform distances are also conceivable. Thereby, a plurality of cords 104 surrounded by the rubber material 106 having a substantially uniform density or other desired density are created. When the drive mechanism 114 rotates, the strip extruder 108 uses heat and pressure to extrude the rubber material 106 onto the plurality of cords 104. The strip extruder 108 may be an extrusion die head. The extrusion die head can form extrusion strips 102 of various shapes and sizes. The plurality of cords 104 provide sufficient rigidity to the extrusion strip 102 without the need for additional support, such as a conveyor belt. In some examples, the system 100 can also include a conveyor belt. The drive mechanism 114 pulls the extrusion strip 102 from the strip extruder 108, and the plurality of cords 104 provide rigidity and strength so that the extrusion strip 102 can be stored or moved to the next step in the manufacturing process.

[0010] After passing through the strip extruder 108, the extruded strip 102 can, optionally, have a substantially uniform coating of rubber material 106 that surrounds the plurality of cords 104. The thickness of the rubber material 106 that surrounds the plurality of cords 104 can depend on the dimensions and specifications of the strip extruder 108. The thickness of the rubber material 106 that surrounds the plurality of cords 104 can vary depending on the particular type of rubber material used to manufacture the extruded strip 102. The thickness of the rubber material 106 that surrounds the plurality of cords 104 can be selected to conform to the final manufacturing specifications of the extruded strip 102.

[0011] In the absence of defects, the extruded strip 102 comprises all of the plurality of cords 104 that preceded the strip extruder 108, with a substantially uniform density, surrounded by a substantially uniform layer of rubber material 106, and connected throughout the length of the extruded strip.

[0012] Optionally (e.g., due to manufacturing variations, irregularities, errors, etc.), there may be defects in the extruded strip 102. For example, in the extruded strip 102, the rubber material 106 that surrounds a portion of the plurality of cords 104 may be absent. As a result, one or more of the plurality of cords 104 may not be surrounded by any rubber material 106. Alternatively, one or more of the plurality of cords 104 may be surrounded by a non-uniform layer of rubber material 106. The non-uniform layer can include a first portion of the rubber material 106 included in the extruded strip 102. The first portion has one or more properties that are different from a second portion of the rubber material that is also present in the extruded strip (e.g., a second portion that is near or adjacent to the first portion). Examples of different properties can include different thicknesses, different surface finishes (e.g., smoother, rougher, etc.). There may also be defects in the extruded strip 102 if one or more of the plurality of cords 104 are damaged, chipped, or broken, i.e., discontinuous along the length of the extruded strip 102, or damaged.

[0013] To detect defects present in the extruded strip 102, the defect detection system 100 includes a thermal imaging sensor 110. The thermal imaging sensor 110 can operate by measuring the thermal radiation of the extruded strip 102. The thermal imaging sensor 110 is electrically connected to a processing unit 112. The thermal imaging sensor 110 is positioned to detect a plurality of surface temperatures of the surface of the extruded strip 102 when the extruded strip 102 exits the strip extruder 108. As shown in FIG. 1, the thermal imaging sensor 110 has a field of view 118 of the extruded strip 102. The field of view 118 substantially corresponds to the region 120 of the surface of the extruded strip 102 as shown in FIG. 2.

[0014] The thermal imaging sensor 110 is configured to detect a plurality of surface temperatures of the surface of the extruded strip 102. As already described, the extruded strip 102 is formed by combining a rubber material 106 and a plurality of cords 104. Prior to exiting the strip extruder 108, the rubber material 106 is heated to a high temperature in order to properly extrude the rubber material 106 so as to surround the plurality of cords 104. As a non-limiting example, the rubber material 106 may be about 95 - 100 °C depending on the manufacturing process. By heating the rubber material 106 to a high temperature, an appropriate flow of the rubber material 106 exiting the strip extruder 108 is obtained. The plurality of cords 104 are maintained at a substantially lower relative temperature (e.g., at least 20 °C lower, such as about 50 °C lower) than the rubber material 106. For example, the plurality of cords 104 may be at a temperature similar to the ambient manufacturing environment. Optionally, the plurality of cords 104 may be at a temperature controlled to a specific temperature, including a temperature lower than the ambient manufacturing environment. The plurality of cords 104 are at a lower temperature than the rubber material 106 prior to the bonding.

[0015] Due to the high temperature of the heated rubber material 106 and the relatively low temperature of the plurality of cords 104, there is a temperature difference between the two materials. As the extrusion strip 102 exits the strip extruder 108, the heated rubber material 106 and the plurality of cords 104 at a relatively low temperature begin to approach an equilibrium temperature. Here, approaching the equilibrium temperature is used to mean that the temperature of the extrusion strip 102 approaches a substantially uniform temperature, that is, the rubber material 106 and the plurality of cords 104 approach thermal equilibrium, and it is not necessarily the case that the extrusion strip 102 approaches thermal equilibrium with the surrounding manufacturing environment. The equilibrium temperature of the extrusion strip 102 is typically about 95 °C or lower. This range of temperatures aids in the vulcanization process of the rubber material 106. The equilibrium temperature is determined by a variety of factors including, but not limited to, the amount of rubber material 106 extruded from the strip extruder 108, the number of the plurality of cords 104, and the thermal conductivity characteristics of the rubber material 106 and the plurality of cords 104.

[0016] The thermal imaging sensor 110 is typically positioned along the direction of product flow at a point after the extrusion strip 102 exits the strip extruder 108. In this way, the thermal imaging sensor is positioned at a location where the combination of the plurality of cords 104 and the rubber material 106 forming the extrusion strip 102 begins to approach the equilibrium temperature but has not yet reached such an equilibrium temperature. Also, the thermal imaging sensor 110 is positioned to detect the plurality of surface temperatures of the surface of the extrusion strip 102 (for example, having a detection field facing such a surface).

[0017] The thermal imaging sensor 110 may be positioned perpendicular to the direction of product flow at various different positions after passing through the strip extruder 108. In one example, the thermal imaging sensor 110 is positioned above the upper surface of the extrusion strip 102 as shown in FIG. 1. In another example, the thermal imaging sensor 110 is positioned below the bottom surface of the extrusion strip 102. The thermal imaging sensor 110 is typically positioned so as to be able to view at least a portion of the surface of the extrusion strip 102.

[0018] The defect detection system 100 may include a plurality of thermal image sensors 110. In one example, a first thermal image sensor 110 may have a field of view 118 and be positioned above the upper surface of the extrusion strip 102, and a second thermal image sensor 111 may have a field of view 119 and be positioned below the bottom surface of the extrusion strip 102.

[0019] In another example, both the first thermal image sensor 110 and the second thermal image sensor 111 may be positioned above the upper surface of the extrusion strip 102.

[0020] In some examples, both the first thermal image sensor 110 and the second thermal image sensor 111 may be positioned below the bottom surface of the extrusion strip 102.

[0021] In such a configuration where a plurality of image sensors are on the same side of the extrusion strip 102, the first image sensor 110 may be positioned to view a first portion of the surface of the extrusion strip 102, and the second thermal image sensor 111 may be positioned to view a second portion of the surface of the extrusion strip 102.

[0022] Alternatively, the first thermal image sensor 110 and the second thermal image sensor 111 may be positioned to view an overlapping portion of the surface of the extrusion strip 102, or at least partially view the same portion.

[0023] In multiple examples, one or more thermal image sensors 110 can be positioned above the upper surface, below the bottom surface, and in any and all combinations thereof.

[0024] The thermal imaging sensor 110 is electrically connected to the processing unit 112. In some examples, a second thermal imaging sensor 111 is also electrically connected to the processing unit 112. In other examples, the thermal imaging sensor 111 is electrically connected to a second processing unit. The processing unit 112 may be a microprocessor, a microcontroller, a computer, a manufacturing management system, a vision controller, any other device capable of processing data, or any other suitable device. The processing unit 112 may be included in the thermal imaging sensor 110, or the processing unit 112 may be separated from the thermal imaging sensor 110 as shown in FIG. 1.

[0025] The thermal imaging sensor 110 is configured to detect a plurality of surface temperatures of the surface of the extrusion strip 102 when the extrusion strip 102 passes through the field of view 118 of the thermal imaging sensor 110. The plurality of surface temperatures may be detected, for example, as a single value, or as a range of values, such as a range of 2 °C.

[0026] The processing unit is configured to generate a thermal map of the extrusion strip 102 based on the plurality of surface temperatures detected by the thermal imaging sensor 110. This thermal map may substantially correspond to the area 120 of the extrusion strip 102 within the field of view 118 of the thermal imaging sensor 110. The area 120 may be a predetermined length of a portion of the extrusion strip 102 and a predetermined portion or all of the width of the extrusion strip 102. Since the extrusion strip 102 is pulled by the drive mechanism 114, the area 120 of the extrusion strip 102 is constantly changing. Therefore, the thermal map generated by the processing unit may be updated periodically as the extrusion strip 102 exits the strip extruder 108.

[0027] The generated thermal map, which exists in two dimensions, may include a series of data points. The first dimension of the thermal map may include a series of data points that approximately correspond to a portion of the length of the extrusion strip 102. The second dimension of the thermal map may include a series of data points that correspond to a portion or all of the width of the extrusion strip 102. A series of data points along a portion of the length and width of the extrusion strip 102 can thus generate a two-dimensional array (e.g., a map) of temperatures at various points in the region 120 of the extrusion strip 102. Each value of the two-dimensional array may correspond to the temperature at a specific location on the extrusion strip 102.

[0028] In addition to being configured to generate a thermal map of the extrusion strip 102, the processing unit 112 may be configured to perform a number of processing functions on the plurality of surface temperatures of the extrusion strip 102. For example, the processing unit 112 may be configured to filter a thermal image, i.e., a plurality of surface temperatures, to reduce noise that may occur in the thermal image detected by the thermal image sensor 110. The processing unit 112 may be configured to smooth the plurality of surface temperatures to reduce noise that may occur in the plurality of surface temperatures detected by the thermal image sensor 110.

[0029] The processing unit 112 may be configured to calculate various thermal metrics based on the thermal map of the extrusion strip 102. Based on the calculated metrics of the thermal map, the processing unit 112 may detect the presence and / or location of a defect 122 in the extrusion strip 102. The defect may be due to damaged or missing code, or it may be due to missing rubber material.

[0030] In some examples, the processing unit 112 may calculate the temperature difference between the data points in the thermal map and the average. In some examples, the processing unit 112 may calculate whether the temperature at a particular point deviates from a particular range, a standard deviation level, or other tolerance range. Temperatures that deviate from the tolerance range may indicate a defect in the extrusion strip 102. Whether the temperature is higher or lower than the tolerance range may indicate the type of defect present in the extrusion strip 102. For example, if the temperature is lower than the tolerance range, it may indicate that there is a lack of the rubber material 106 in the extrusion strip 102 because the rubber material 106 is at a higher temperature compared to the plurality of cords 104 prior to the strip extruder 108. This can occur when the rubber material 106 is flowing improperly within the strip extruder 108. Among the plurality of positions of the extrusion strip where there are locations lacking the rubber material, the temperature at the position lacking the rubber material or at a point near it will be lower than if there were a sufficient amount of the rubber material present. As a result, the temperature at the position lacking the rubber material or at a point near it will be lower than the tolerance range. This may represent a defect present in the extrusion strip 102.

[0031] Similarly, if the temperature is higher than the tolerance range, it may indicate that one or more of the plurality of cords 104 are damaged or missing from the extrusion strip 102 because the plurality of cords 104 are at a lower temperature compared to the rubber material 106 preceding the strip extruder 108. Among the plurality of positions of the extrusion strip where the cord is damaged or missing, the temperature at the position where the cord is damaged or missing or at a point close thereto will be higher than when the cords are connected because there is no relatively low-temperature cord that absorbs the heat of the rubber. As a result, the temperature at the position where the cord is damaged or missing or at a point close thereto will be higher than the tolerance range. This may represent a defect present in the extrusion strip 102. In some examples, a temperature higher than the tolerance range may also indicate that the rubber is thickly deposited (compared to the portions surrounding the extrusion strip 102), which may also represent a defect.

[0032] The processing unit 112 may be configured to determine that there are a plurality of defects in the extrusion strip 102. For example, the processing unit 112 may be configured to determine that at a first position of the extrusion strip 102, the temperature is higher than the tolerance range, which indicates that the cord is damaged, broken, or missing, and at a second position of the extrusion strip 102, the temperature is lower than the tolerance range, which indicates that the rubber material is lacking. As another example, the processing unit 112 may be configured to determine that at two separate positions of the extrusion strip 102, the temperature is higher than the tolerance range, which indicates that a plurality of cords of the extrusion strip 102 are damaged, broken, or missing.

[0033] The processing unit 112 may be configured to determine the position, shape, and / or size of the defect. For example, based on the temperatures at a plurality of points of the thermal map that are different from other plurality of points of the thermal map of the extrusion strip 102, the processing unit 112 may be configured to determine where the defect starts and ends along the direction in which the product of the extrusion strip 102 flows. The processing unit 112 may also be configured to determine the width of the defect, i.e., the distance perpendicular to the direction in which the product flows. The processing unit 112 may also be configured to determine the shape of the defect based on the temperatures determined in comparison with other plurality of points of the thermal map of the extrusion strip 102.

[0034] The processing unit 112 may be configured to communicate with one or more of the devices in the defect detection system 100. For example, if the processing unit 112 determines that there is a defect in the extrusion strip 102, the processing unit 112 may communicate with the drive mechanism 114 and stop pulling the extrusion strip 102, or alternatively, may interrupt the manufacturing function or interfere with the manufacturing function. Thereby, the manufacturing process of the extrusion strip 102 may be stopped. Stopping the production of the extrusion strip 102 containing the defect may help prevent an overabundance of manufacturing waste. Thereby, the operator can also address the presence of the defect in the extrusion strip 102, correct the error, and return to normal production of the extrusion strip 102.

[0035] The processing unit 112 of the defect detection system 100 may be configured to communicate with one or more external devices. For example, when the processing unit 112 determines that there is a defect in the extrusion strip 102, the processing unit 112 may communicate with an external device such as a supply hopper for the rubber material 106 or one or more spools that supply the plurality of cords 104. Thereby, the manufacturing process of the extrusion strip 102 may be stopped. Stopping the production of the extrusion strip 102 containing defects prevents an excess of manufacturing waste. Thereby, the operator can also address the presence of defects in the extrusion strip 102, correct the errors, and return to the normal production of the extrusion strip 102.

[0036] The defect detection system 100 may further include a data storage device electrically connected to the processing unit 112. The data storage device may be configured to store a thermal map, calculated metrics, and / or the presence of defects of the extrusion strip. Thereby, the traceability and / or history retention of the data generated by the processing unit 112 becomes possible. The data storage device may be local, i.e., located at or near the processing unit 112. Or, the data storage device may be a remote storage device, i.e., located at a different location in the manufacturing facility or on a cloud server. The data storage device may be any type of memory device including, but not limited to, random access memory (RAM), read only memory (ROM), hard disk drive, solid state drive, optical disk drive, and / or cloud storage.

[0037] The defect detection system 100 may include an audio output device electrically connected to the processing unit 112. The audio output device may be configured to generate an audible sound when the processing unit 112 detects a defect in the extrusion strip 102. The audio output device may be a horn, a speaker, a siren, or other similar device configured to generate an audible sound. The audio output device serves to alert the manufacturing operator that a defect has been detected in the extrusion strip 102 by the defect detection system 100, making it audible.

[0038] The defect detection system 100 may include a light-emitting device electrically connected to the processing unit. The light-emitting device may be configured to generate a visual indicator when the processing unit 112 detects a defect in the extrusion strip 102. The light-emitting device may be a light-emitting diode, an incandescent lamp, a halogen lamp, a fluorescent lamp, or other similar device configured to generate a visual indicator. The light-emitting device serves to visually alert the manufacturing operator that a defect has been detected in the extrusion strip 102 by the defect detection system 100.

[0039] In another example, the defect detection system 100 includes a marking device electrically connected to the processing unit 112. The marking device may be configured to mark the extrusion strip at the location where the processing unit 112 detects a defect present in the extrusion strip 102.

[0040] In another example, the defect detection system 100 includes an operator interface device electrically connected to the processing unit. The operator interface device may be a liquid crystal display, a light emitting diode display, a segment display, or other digital display device. The operator interface device may be configured to display a thermal map of the surface of the extruded strip. The operator interface device may also be configured to display the temperature profile of the extruded strip. In other examples, the operator interface device may be configured to display the presence of defects in the extruded strip and / or the location of defects in the extruded strip. By using the operator interface device, an operator can visually monitor the thermal map, the temperature profile, or other data outputs from the processing unit. Thereby, the operator can better understand whether the manufactured extruded strip complies with the manufacturing specifications. Also, thereby, the operator can set the extruded strip 102 and the defect detection system 100, solve these problems, or monitor their manufacturing.

[0041] As described, since the rubber material 106 and the plurality of cords 104 are at relatively different temperatures, the defect detection system 100 may detect defects present in the extrusion strip 102 by determining whether the temperature is outside the tolerance range. For example, if there is a lack of rubber material 106 in the extrusion strip 102, the thermal imaging sensor 110 may detect a surface temperature at or near the location where the rubber material is missing that is lower than in the case of a properly functioning manufacturing process. This is because there is less high-temperature rubber material and the equilibrium temperature of the extrusion strip at or near that location decreases. In another example, if one or more of the plurality of cords 104 are damaged and discontinuous, i.e., broken or missing, the thermal imaging sensor 110 may detect a surface temperature at or near the location where the cord is missing that is higher than in the case of a properly functioning manufacturing process. This is because there is less cord material absorbing heat from the relatively high-temperature rubber material and the equilibrium temperature of the extrusion strip at or near that location increases.

[0042] By using a thermal imaging sensor and a processing unit to detect temperature differences in the extrusion strip, the defect detection system can determine whether there are defects in the extrusion strip. This system can help prevent the production of excessive defective products prior to detecting the presence of defects. Since the thermal imaging sensor 110 and the processing unit 112 are located relatively close to the strip extruder 108, the defect detection system 100 can determine the presence of defects before a significant portion of the defective product is extruded. This helps reduce manufacturing waste of defective products. Also, this helps prevent an extruded strip with defects from being incorporated into the final tire assembly. If an extruded strip with defects is incorporated into the final tire assembly, the entire tire assembly may have to be disassembled, resulting in wasted costs.

[0043] The use of a thermal imaging sensor and a processing unit to detect defects in an extruded strip can be realized by various manufacturing specifications of the extruded strip, such as various cord materials, colors, and sizes, rubber materials, and / or various widths, thicknesses, cord densities, etc. The defect detection system 100 can detect defects in the production of extruded strips of a plurality of cords 104 of various different materials. For example, depending on the manufacturing process, the plurality of cords 104 may consist of a metal compound such as steel, or a textile material such as polyester, nylon, aramid, or any other suitable material. Thus, the plurality of cords 104 may be of various different colors. The defect detection system 100 can detect defects in the production of extruded strips of various different rubber formulations. The defect detection system 100 is configured to determine the temperature profile of the extruded strip and to determine whether there is a temperature difference between the temperature profile and the average temperature along the profile line, so the system can detect various defects under a variety of manufacturing conditions. Further, while the embodiments described herein generally relate to one or more cords surrounded by an extruded material, the aspects described herein can be used to detect defects (or other features detectable via temperature analysis) whenever two different materials having a temperature difference are combined during an extrusion process or a bonding process.

[0044] As a non-limiting example, the defect detection system may be used to detect defects in the extrusion of plastic onto another material such as fiber, metal, etc. The defect detection system utilizes a thermal imaging sensor to detect a plurality of surface temperatures of the surface of the bonding material. The bonding material may be formed by combining a first material and a second material together to form a single combined structure. Prior to forming the bonding material, the first material may have a higher temperature compared to the second material. When the two materials are bonded, the resulting bonding material may begin to reach an equilibrium temperature. The thermal imaging sensor of the defect detection system may detect a plurality of surface temperatures of the surface of the resulting bonding material. As already described with reference to FIGS. 1 and 2, the processing unit may generate a thermal map based on the plurality of surface temperatures, calculate various thermal metrics, and determine the presence of defects in the resulting bonding material.

[0045] FIG. 3 is a flowchart showing an exemplary embodiment of a method for detecting defects in an extrusion strip of the system of FIG. 1. As described with reference to FIG. 1, the defect detection system may be used to detect the presence of defects in the extrusion strip using a thermal imaging sensor. Thus, at 302, the thermal imaging sensor may be used to scan the extrusion strip and generate a thermal image of the area of the extrusion strip. As already described, the thermal imaging sensor may detect the thermal radiation emitted by the extrusion strip and determine a plurality of surface temperatures of the surface of the extrusion strip.

[0046] Subsequently, the thermal image may be processed at 304 to generate a thermal map. As already described with respect to FIG. 1, a filter may be applied to the thermal image to reduce any noise that may occur in the thermal image. By doing so, any anomalies present in the thermal image of the extrusion strip are reduced and the actual surface temperature of the extrusion strip may be more accurately shown. The thermal map may be a two-dimensional array of surface temperatures of a portion of the extrusion strip.

[0047] Based on the thermal map of the extrusion strip, at 306, the processing unit may calculate the thermal metrics of the thermal map. For example, the average temperature of the thermal map may be calculated. In some examples, the average temperature may be calculated based on the entire thermal map or a two-dimensional portion of the thermal map. In some examples, the average temperature may be calculated along a single line of the thermal map, such as a series of points corresponding to a portion of the length of the extrusion strip or a series of points corresponding to the width of the extrusion strip. The average temperature may be calculated based on any combination of these methods. Additionally, the standard deviation of the thermal map may be calculated. The standard deviation may be calculated based on the entire thermal map, a two-dimensional portion of the thermal map, or along a single line of the thermal map. As described for the average temperature, the standard deviation may be calculated based on any one of these methods alone or any combination of these methods. Other thermal metrics may also be calculated, including maximum, minimum, mean, median, and / or range.

[0048] Based on the calculated thermal metrics, at 308, the processing unit may evaluate whether the code is damaged or missing in the extrusion strip. The evaluation of the thermal map is shown in more detail in FIG. 4 and described below. If the processing unit determines that the code is damaged or missing in the extrusion strip, at 310, the processing unit may communicate about the detection of the defect in the extrusion strip. As described in more detail with reference to FIG. 1, the processing unit may communicate with one or more devices, stop the production of the extrusion strip, and / or alert the operator by various additional external devices, such as turning on an alarm or lighting an indicator light.

[0049] Based on the calculated heat metrics, the processing unit may additionally evaluate, at 312, whether the rubber material is missing from the extrusion strip. This evaluation can be carried out as shown in Figure 4 and as described in more detail below. If the processing unit determines that there is missing rubber in the extrusion strip, the processing unit may communicate, at 314, about the detection of the defect in the extrusion strip.

[0050] In some examples, the evaluation at 312 of whether the rubber material is missing from the extrusion strip is performed prior to the evaluation at 308 of whether the cord is damaged or missing in the extrusion strip. In other examples, these steps may be combined and performed simultaneously. It should be understood that modifications or changes to the order of other steps are within the scope of this specification.

[0051] Figure 4 is a flowchart of an example method for evaluating whether there are heat-related defects in an extruded strip of a defect detection system, as performed in step 308 and / or step 312. Based on a series of temperature data points of the thermal map, the processing unit may determine, at 402, positions where the temperature is outside the tolerance range. As already described with reference to FIG. 1, the tolerance range may be a specific temperature range or a standard deviation level. The tolerance range may be a fixed predetermined value. This value may be based on experiments, tests, or other manufacturing verification tests. Alternatively, the tolerance range may be a dynamic value that varies based on various properties of the rubber material or multiple cords prior to extrusion, such as thermal conductivity, material type, amount of material, temperature, or other properties, and / or extrusion speed, volume, or other manufacturing conditions. Thus, defects can be detected under a wide variety of manufacturing conditions and operations. The tolerance range may also be based on other calculated metrics of the thermal map or a combination of calculated metrics. For example, the tolerance range may be based on a calculated formula such as the difference between the highest and lowest temperatures of the thermal map divided by some predetermined amount, or the standard deviation divided by the central temperature. Thus, such a tolerance range can be dynamic and can essentially constitute the current manufacturing operating conditions.

[0052] At 404, the processing unit may evaluate the size and / or shape of the temperature outside the tolerance range. By doing so, the processing unit may determine that the temperature outside the tolerance range is a single data point of the two-dimensional thermal map, or may determine that multiple temperatures are outside the tolerance range. If multiple temperatures are close to each other in the two-dimensional thermal map, the processing unit may consider them together and determine the shape of the temperature outside the tolerance range.

[0053] At 406, the processing unit may determine that a defect has been detected at that location. The processing unit may make this determination based on the size and shape of the temperature outside the tolerance range. For example, the processing unit may determine that there is no defect if the number of data points having a temperature outside the tolerance range is less than a certain value. Data points having a temperature outside the tolerance range may be due to measurement and processing errors rather than defects in the extrusion strip. However, if a sufficient number of data points have a temperature outside the tolerance range, the processing unit may determine that a defect has been detected at that location on the extrusion strip. As described with reference to FIGS. 1 and 3, the processing unit may subsequently communicate about the presence of a defect in the extrusion strip.

[0054] The defect detection system may detect the presence of a defect in the extrusion strip immediately after a plurality of codes and rubber materials are combined / assembled by utilizing the temperature difference of the materials. This can help reduce manufacturing waste and improve the quality control of the produced extrusion strip. This system can be implemented for a wide variety of materials, has a small footprint of operation, and can be implemented in existing manufacturing operations with minimal modifications.

[0055] Although various embodiments have been described, it will be apparent to those skilled in the art that many more embodiments and implementations are possible. Accordingly, the embodiments described herein are examples, and the embodiments and implementations contemplated within the scope of this specification are not limited to these.

[0056] Although various aspects of the subject matter have been described above, additional disclosure that is consistent with the claims initially filed under this disclosure is also described below. When describing this additional subject matter, reference is made to the drawings described previously.

[0057] One general aspect comprises a defect detection system for use with a strip extruder, where a thermal imaging sensor is positioned to detect a plurality of surface temperatures of a surface of an extruded strip as the extruded strip exits the strip extruder, and the extruded strip may include a rubber material surrounding a plurality of cords. The defect detection system also comprises a processing unit electrically connected to the thermal imaging sensor, where the processing unit is configured to generate a thermal map of a region of the surface of the extruded strip based on the plurality of surface temperatures detected by the thermal imaging sensor, and the processing unit is further configured to determine whether the plurality of surface temperatures are outside of a tolerance range indicating the presence of a defect.

[0058] Implementations of this general aspect may incorporate one or more of the following features of this paragraph. The processing unit may be further configured to determine that a plurality of surface temperatures below the tolerance range indicate the presence of a defect due to a lack of rubber material in the extruded strip. The processing unit may be further configured to determine that a plurality of surface temperatures above the tolerance range indicate the presence of a defect because one or more of the plurality of cords of the extruded strip are damaged or missing. The processing unit may be further configured to calculate a thermal metric based on the thermal map and calculate a tolerance range based on the thermal metric. The calculated thermal metric may include at least one of average, minimum, maximum, mean, median, range, or standard deviation. The first thermal imaging sensor may be positioned above the top surface of the extruded strip, and the second thermal imaging sensor may be positioned below the bottom surface of the extruded strip. The audio output device may be configured to generate an audible sound when the processing unit detects the presence of a defect. The light emitting device may be configured to generate a visual indicator when the processing unit detects the presence of a defect. The marking device may be configured to mark the extruded strip at the location where the processing unit detects the presence of a defect. The operator interface device may be configured to display the thermal map. The data storage device may be configured to store the thermal map. The processing unit may be further configured to determine the number of cords not present in the extruded strip. The plurality of cords of the extruded strip may be made of a metal material. The plurality of cords of the extruded strip may be made of a nylon material. The plurality of cords of the extruded strip may be made of a fabric material. The thermal imaging sensor may be positioned above the top surface of the extruded strip and / or the thermal imaging sensor may be positioned below the bottom surface of the extruded strip.

[0059] Another general aspect includes a defect detection system, where a thermal imaging sensor is positioned to detect a plurality of surface temperatures of the surface of a bonded structure. The bonded structure may include a first material bonded to a second material, and the first material has a higher temperature compared to the second material prior to being bonded. The defect detection system also includes a processing unit electrically connected to the thermal imaging sensor. The processing unit is configured to generate a thermal map of a region of the surface of the bonded structure based on the plurality of surface temperatures detected by the thermal imaging sensor, and the processing unit is further configured to determine whether the plurality of surface temperatures are outside an acceptable tolerance range indicating the presence of a defect. Implementations of this general aspect may incorporate one or more of the following features. The processing unit may be further configured to calculate a thermal metric based on the thermal map and calculate an acceptable tolerance range based on the thermal metric.

[0060] Another general aspect includes a defect detection method for use with an extrusion stripper that uses a thermal imaging sensor to detect a plurality of surface temperatures of the surface of an extrusion strip. The extrusion strip may include a rubber material surrounding a plurality of cords. The defect detection method also includes processing the plurality of surface temperatures by a processing unit electrically connected to the thermal imaging sensor to generate a thermal map of a region of the surface of the extrusion strip, calculating a thermal metric based on the thermal map by the processing unit, calculating an acceptable tolerance range based on the thermal metric by the processing unit, and evaluating by the processing unit whether the plurality of surface temperatures are outside an acceptable tolerance range indicating the presence of a defect. Implementations of this general aspect may incorporate one or more of the following features. The method may further include communicating the presence of the defect to an external device. The method may further include determining the size, shape, and location of the defect where it exists.

[0061] Another general aspect comprises a non-transitory computer-readable medium including stored computer-readable instructions, the stored computer-readable instructions being loaded and executed by a processor to implement a method for detecting a defect, the method including using a thermal imaging sensor to detect a plurality of surface temperatures of a surface of an extrusion strip, the extrusion strip optionally including a rubber material surrounding a plurality of cords. The method also includes processing the plurality of surface temperatures by a processing unit electrically connected to the thermal imaging sensor to generate a thermal map of an area of the surface of the extrusion strip, calculating a thermal metric based on the thermal map by the processing unit, calculating a tolerance range based on the thermal metric by the processing unit, and evaluating by the processing unit whether the plurality of surface temperatures are outside the tolerance range indicating the presence of a defect.

Claims

1. A defect detection system for use with a strip extrusion machine, the defect detection system comprising: A thermal imaging sensor positioned to detect a plurality of surface temperatures of a surface of the extruded strip when the extruded strip exits the strip extrusion machine, the thermal imaging sensor wherein the extruded strip comprises a rubber material surrounding a plurality of cords; and a processing unit electrically connected to the thermal imaging sensor Comprising The processing unit is configured to generate a thermal map of the region of the surface of the extruded strip based on the plurality of surface temperatures detected by the thermal imaging sensor The processing unit is further configured to determine whether the plurality of surface temperatures are outside an acceptable tolerance range indicating the presence of a defect. A system

2. Based on the small amount of the rubber material, the processing unit is further configured to determine that the plurality of surface temperatures are lower than the acceptable tolerance range. The system according to claim 1

3. Based on one or more of the plurality of cords being damaged or chipped, the processing unit is further configured to determine that the plurality of surface temperatures are higher than the acceptable tolerance range. The system according to claim 1

4. The processing unit is further configured to calculate a thermal metric based on the thermal map and calculate the acceptable tolerance range based on the thermal metric. The system according to claim 1

5. The calculated thermal metric includes at least one of mean, minimum, maximum, mean, median, range, or standard deviation. The system according to claim 4

6. A first thermal imaging sensor is positioned above the upper surface of the extruded strip, and a second thermal imaging sensor is positioned below the lower surface of the extruded strip. The system according to claim 1

7. Further comprising an audio output device electrically connected to the processing unit, the audio output device being configured to generate an audible sound when the processing unit detects the presence of the defect. The system according to claim 1

8. The system according to claim 1, further comprising a light-emitting device electrically connected to the processing unit, wherein the light-emitting device is configured to generate a visual indicator when the processing unit detects the presence of the defect.

9. The system according to claim 1, further comprising a marking device electrically connected to the processing unit, wherein the marking device is configured to mark the extrusion strip at a position where the processing unit detects the presence of the defect.

10. The system according to claim 1, further comprising an operator interface device electrically connected to the processing unit, wherein the operator interface device is configured to display the thermal map.

11. The system according to claim 1, further comprising a data storage device electrically connected to the processing unit, wherein the data storage device is configured to store the thermal map.

12. The system according to claim 1, wherein the processing unit is further configured to determine the number of the plurality of codes that do not exist in the extrusion strip.

13. The system according to claim 1, wherein the plurality of codes of the extrusion strip are made of a metallic material.

14. The system according to claim 1, wherein the plurality of codes of the extrusion strip are made of a nylon material.

15. The system according to claim 1, wherein the plurality of codes of the extrusion strip are made of a fabric material.

16. The system according to claim 1, wherein the thermal imaging sensor is positioned above the upper surface of the extrusion strip.

17. The system according to claim 1, wherein the thermal imaging sensor is positioned below the bottom surface of the extrusion strip.

18. A defect detection system, the defect detection system comprising a thermal imaging sensor positioned to detect a plurality of surface temperatures of a surface of a bonding structure, the bonding structure including a first material bonded to a second material, the first material having a higher temperature than the second material prior to being bonded, the thermal imaging sensor; a processing unit electrically connected to the thermal imaging sensor and comprising The processing unit is configured to generate a thermal map of the region of the surface of the bonding structure based on the plurality of surface temperatures detected by the thermal image sensor. The system, wherein the processing unit is further configured to determine whether the plurality of surface temperatures are outside a tolerance range indicating the presence of a defect.

19. The system according to claim 18, wherein the processing unit is further configured to calculate a thermal metric based on the thermal map and calculate the tolerance range based on the thermal metric.

20. The system according to claim 18, wherein the processing unit is further configured to determine that the plurality of surface temperatures lower than the tolerance range indicate the presence of a defect due to the absence or damage of the first material of the bonding structure.

21. The system according to claim 18, wherein the processing unit is further configured to determine that the plurality of surface temperatures higher than the tolerance range indicate the presence of a defect due to the absence or damage of the second material of the bonding structure.

22. The system according to claim 18, further comprising a data storage device electrically connected to the processing unit, the data storage device being configured to store the thermal map.

23. A defect detection method for use with a strip extruder, comprising: detecting, using a thermal image sensor, a plurality of surface temperatures of a surface of an extruded strip including rubber surrounding a plurality of cords; processing, by a processing unit electrically connected to the thermal image sensor, the plurality of surface temperatures to generate a thermal map of a region of the surface of the extruded strip; calculating, by the processing unit, a thermal metric based on the thermal map; calculating, by the processing unit, a tolerance range based on the thermal metric; and evaluating, by the processing unit, whether the plurality of surface temperatures are outside the tolerance range indicating the presence of a defect. A method comprising.

24. The method according to claim 23, further comprising communicating the presence of the defect to an external device.

25. The method according to claim 23, further comprising determining the size, shape, and location of the defect.

26. A non-transitory computer-readable medium comprising stored computer-readable instructions, wherein the stored computer-readable instructions are loaded and executed by a processor to implement a method for detecting a defect, the method comprising: Detecting a plurality of surface temperatures of a surface of an extrusion strip using a thermal imaging sensor, the extrusion strip including rubber surrounding a plurality of cords; Processing the plurality of surface temperatures by a processing unit electrically connected to the thermal imaging sensor to generate a thermal map of a region of the surface of the extrusion strip; Calculating a thermal metric based on the thermal map and calculating a tolerance range based on the thermal metric by the processing unit; Evaluating by the processing unit whether the plurality of surface temperatures are outside the tolerance range indicating the presence of a defect; comprising: A non-transitory computer-readable medium.

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