Blow molding method using a closed-loop oven system

Abstract

A closed loop method of heating preforms for blow molding is provided that includes inspecting the preform upon entry into the system, heating the preform, measuring the temperature of the preform around its longitudinal axis, heating the preform again, measuring the temperature of the preform around its longitudinal axis again, comparing the second temperature measurement to known acceptable temperature measurements, and optimizing the heating step to ensure subsequent optimization of heating of subsequent preforms.

Description

Technical Field

[0001] The present technology relates to a system and a process capable of subjecting a preform to a blow molding process for manufacturing a plurality of preforms having a plurality of temperature profiles.

Background Art

[0002] This section provides background information related to the present disclosure that is not necessarily prior art.

[0003] Various products are distributed in plastic containers such as containers formed from one or more polymers. Common polymers used to form containers include polyesters such as polyethylene terephthalate (PET), high-density and low-density polyethylene (PE), polypropylene (PP), polycarbonate (PC), and the like. Plastic containers can be manufactured using various blow molding processes including injection blow molding, hydraulic blow molding, and extrusion blow molding, and in such blow molding processes, a preform can be used to form a container that is inflated by a fluid and results therefrom.

[0004] Injection blow molding can be used to form certain plastic containers in one or more stages and can include the use of a stretch rod. In a two-stage injection stretch blow molding method, first, a polymer can be molded into a preform using an injection molding method. The preform can include a neck and a finish of the container to be formed (which can include a threaded portion thereon), and a closed distal end. Then, the preform can be heated above the glass transition temperature of the polymer, optionally stretched longitudinally with a stretch rod, and blown into a container that conforms to a mold using a high-pressure gas (e.g., air). As the preform expands, it is stretched and stretched to the shape of the mold cavity. The polymer contacts the cold surface of the mold and solidifies, and the completed hollow container is then discharged from the mold.

[0005] Hydraulic blow molding allows for the molding and filling of containers in a single operation. A liquid product is used to mold a polymer preform within a mold, which is then filled into the resulting container, with the liquid product remaining in the finished container afterward. The heated preform is very similar to those used in injection blow molding; it is placed within the mold, optionally stretched, and then rapidly inflated or filled using a liquid product instead of gas to form the container. Therefore, the combination of molding and filling processes can optimize the packaging of liquid products by eliminating the need for transporting empty containers and the time constraints associated with subsequent filling operations.

[0006] Various types of preforms can be used in such blow molding processes. Specific embodiments of the preform include injection-molded rotationally symmetric preforms having an elongated cylindrical side body, a rounded closed bottom, and a neck with an upward opening. Other preforms are rotationally asymmetric, with thickness varying along the elongated axis to facilitate material distribution for forming an asymmetrical container. In either case, an external threaded finish section may be present, located near the opening, and this threaded finish section may be demarcated toward the bottom by a collar or the like. The threaded finish section can be preserved during the blow molding of the preform, and this finish can, for example, form threads for a screw cap on the finished beverage container. In contrast, the rest of the preform can be deformed or stretched during the blow molding process. To enable blow molding in the desired manner, the preform can be heated to a predetermined temperature. Heating can be carried out by various means, including infrared radiation using an infrared oven, which can effectively provide specified and / or uniform temperature control of the preform.

[0007] In particular, the polymer material of the preform (e.g., PET) can be such that the polymer strains and hardens as it is stretched. Therefore, the molding temperature during the blow molding process can be a decisive factor in the resulting container. The strain hardening effect can be considered in the manufacture of PET containers for the purpose of controlling and optimizing the wall thickness distribution. Depending on the manufacturing process, it is possible to heat the preform by infrared radiation so that it is heated according to a temperature profile. In this way, warmer parts of the preform can be deformed preferentially over other parts, insofar as the stretch resistance resulting from strain hardening becomes greater than, for example, the resistance of adjacent colder parts. The temperature profile can be uniformly distributed around the preform and can be process-dependently varied along the longitudinal axis of the preform. To apply a desired temperature profile to the preform, a number of heating zones, for example, up to nine or more zones, can be used. Multiple different heating zones can be controlled individually, so that the selected settings are maintained constant over a longer period of time that the heating device is operating.

[0008] Preforms with different structures may require different heating regimes or methods as preparation for blow molding into the resulting container. For example, preforms formed or containing different sizes, shapes, thicknesses, different polymers or polymer combinations, layers, etc., may each have a predetermined temperature profile optimized for a specific blow molding process. A specific example involves different heating regimes to produce different temperature profiles for a PET preform compared to a PP preform. Another example involves different heating regimes to produce the same temperature profile, but the preform may have different properties that require different regimens to achieve the same temperature profile (e.g., preforms formed from the same material but with different thicknesses). Thus, various heating parameters, including the number of heating zones, the temperature of specific heating zones, and the exposure time to specific heating zones, can be adjusted to suit a particular preform.

[0009] Blow molding systems often include preform heating means adjacent to them, and the heated preform can be quickly transferred to a mold before the desired temperature profile of the preform changes, thus forming the resulting vessel. For example, the preform's path through an infrared oven can be adjusted to produce a predetermined temperature profile for a given preform. However, if the conditions of the blow molding system and / or process change, it may be necessary to change the preform path or heating means to adapt to the new temperature profile for a given preform. Changes in blow molding conditions include using a different preform type, changing the mold, changing blow molding parameters, etc. Therefore, it can be difficult to adapt the blow molding system and / or process to changes in conditions that require changes in the preform temperature profile while maintaining continuous or high-throughput production of vessels. To accommodate preforms with different properties, it is often necessary in a blow molding system to change one or more settings, reach one or more new equilibria, and adapt one or more physical parameters. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] Without proper temperature control, heated preforms may have improper material distribution and / or expansion during the blow molding operation, resulting in containers that may burst (or "blow out") or fail aesthetic inspections. In refined gas blow molding processes, it is estimated that approximately 1,500 to 2,500 containers per million gas blow molded containers will experience blowouts. The expected blowouts from liquid blow molded containers are roughly the same. In liquid blow molding, blowouts result in leakage and waste of the liquid product filling the container, more than just air leakage. If the blow molding liquid is water, blowouts may only result in water waste and a very short downtime to dry the blow molding equipment. When the blow molding fluid is, for example, petroleum products, pharmaceuticals, or cosmetics, blowout can result in significant time spent on cleaning procedures required to make the blow molding equipment usable again, as well as wasted or unusable products. Each of these individually may have a significant economic impact on the blow molding process and product costs, and their combination may make the liquid blow molding process for packaging products economically unfeasible. It is desirable to develop a blow molding method that reduces the expected blowout in a blow molding operation (liquid or gas) to approximately 25 blowouts per million molded containers.

[0011] Taking these issues into consideration, this technology provides a method for measuring and monitoring a preform while it is heating in order to minimize blowout during the blow molding process. This makes it possible to maintain blow molding operations continuously or at high throughput. . [Means for solving the problem]

[0012] A method has been remarkably discovered for measuring and monitoring a preform during heating, which minimizes blowout during blow molding, and is consistent with and not contradicts the present invention.

[0013] One embodiment of the present invention provides a method for heating a preform, comprising: preparing a plurality of preforms suitable for blow molding; inspecting each preform to identify at least the material forming the preform; heating each preform; measuring the temperature of at least a portion of each preform around the preform along its longitudinal axis; further heating each preform; a further measurement step of further measuring the temperature of at least a portion of each preform around the preform along its longitudinal axis to generate a temperature profile; comparing the temperature profile from the further measurement step with a standard temperature profile for each of the plurality of preforms; and blow molding a preform having an acceptable temperature profile based on the comparison step.

[0014] Another embodiment of the present invention provides a method for heating preforms, comprising: preparing a plurality of preforms suitable for blow molding; inspecting each preform to identify at least the material forming the preforms; heating each preform; measuring the temperature of at least a portion of each preform around each preform along its longitudinal axis; further heating each preform; a further measuring step of further measuring the temperature of at least a portion of each preform around each preform along its longitudinal axis to generate a temperature profile; comparing the temperature profile from the further measuring step with a standard temperature profile of the plurality of preforms; blow molding preforms having an acceptable temperature profile based on the comparison step, or recycling preforms that do not have an acceptable temperature profile based on the comparison step, or reheating preforms that do not have an acceptable temperature profile based on the comparison step.

[0015] Another embodiment of the present invention provides a method for heating preforms, comprising the steps of: preparing a plurality of preforms suitable for blow molding; inspecting each preform to identify at least the material forming the preforms; heating each preform; measuring the temperature of at least a portion of each preform around each preform along its longitudinal axis; further heating each preform; a further measurement step of further measuring the temperature of at least a portion of each preform around each preform along its longitudinal axis to generate a temperature profile; and during the further measurement step, aggregating the measured temperatures of at least a portion of each preform; and the aggregated measured temperatures The method comprises the steps of: converting the measured temperature of at least a portion of the preform into a three-dimensional thermal image representing the measured temperature of at least a portion of the preform; in a further measurement step, further converting the three-dimensional thermal image into a two-dimensional thermal image representing a portion of the preform measured around the preform along the longitudinal axis of the preform; comparing the two-dimensional thermal image from the further conversion step with a standard two-dimensional thermal image corresponding to one of a plurality of preforms; and, based on the comparison step, blow-molding the preform having an acceptable temperature profile, recycling the preform not having an acceptable temperature profile, or reheating the preform not having an acceptable temperature profile.

[0016] The above and other advantages of the present invention will be readily apparent to those skilled in the art from the following detailed description of preferred embodiments, when considered in light of the accompanying drawings. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic plan view of an oven for heat treatment and thermal imaging of preforms. [Figure 2] Figure 1 is a cross-sectional view including one of the heating means and the preform heated thereby. [Figure 3] This image shows an exemplary three-dimensional thermal image of a heated preform and the corresponding two-dimensional thermal image obtained therefrom. [Figure 4] The images in Figure 3 are selectively dissected to show the results. [Figure 5] Figure 3 shows a side-by-side comparison of the two-dimensional thermal image and the graph of the thermal data used to generate that image. [Modes for carrying out the invention]

[0018] The following technical descriptions are merely illustrative in nature of the subject matter, manufacture, and use of one or more inventions and are not intended to limit the scope, application, or use of any particular invention claimed in this application, or any other application that may be filed claiming priority to this application, or any patent issued therefrom. With respect to the disclosed methods, the order of the steps presented is essentially illustrative and therefore may differ in various embodiments, including when certain steps may be performed simultaneously. As used herein, “A” and “an” indicate the presence of “at least one” of an element, and where possible, there may be multiple such elements. Unless otherwise expressly stated, all numerical quantities herein are understood to be modified by the word “about,” and in describing the broadest scope of the Art, all geometric and spatial descriptions are understood to be modified by the word “substantially.” When applied to numerical values, “about” indicates that the calculation or measurement allows for some inaccuracy in the value (some approach to the accuracy of the value; approximately or reasonably close to the value; nearly). Rather, if for any reason the inaccuracies provided by “about” and / or “substantially” are not understood in the art in this ordinary sense, “about” and / or “substantially” as used herein shall indicate at least the variation that may arise from the ordinary methods of measuring or using such parameters.

[0019] All documents, including patents, patent applications, and scientific literature, cited in this detailed description are incorporated herein by reference unless otherwise specified. In the event of any inconsistency or ambiguity between the documents incorporated by reference and this detailed description, this detailed description shall prevail.

[0020] In this specification, the open-ended term “comprising” is used to describe and require embodiments of the Art, as a synonym for non-restrictive terms such as including, containing, and having. However, embodiments may alternatively be described using more restrictive terms such as “consisting of” or “essentially consisting of.” Thus, with respect to any given embodiment describing a material, component, or process step, even if such additional material, component, or process is not expressly described in this application, the Art also specifically includes embodiments consisting of, or essentially consisting of, such additional material, component, or process step, excluding (where it consists of) the additional material, component, or process that would affect an important characteristic of the embodiment (where it essentially consists of). For example, a description of a component or process describing elements A, B, and C specifically assumes embodiments consisting of, and essentially consisting of, A, B, and C, excluding element D, which may be described in the Art, even if element D is not expressly described as being excluded in this specification.

[0021] As referred to herein, the disclosure of a range includes its endpoints and, unless otherwise specified, all definite values and further divided ranges within the entire range. Thus, for example, a range of "from A to B" or "from about A to about B" includes A and B. The disclosure of values and ranges of values of particular parameters (such as amounts, weight percentages, etc.) does not exclude other values and ranges of values useful herein. It is contemplated that two or more specifically exemplified values for a given parameter can define the endpoints of a range of values that can be claimed for that parameter. Similarly, the disclosure of two or more ranges of values for a parameter (whether such ranges are nested, overlapping, or distinct) is contemplated to include all possible combinations of ranges of values that might be claimed using the endpoints of the disclosed ranges. For example, if parameter X is exemplified herein as having values in the ranges 1-10, or 2-9, or 3-8, then parameter X is also contemplated to have values in other ranges including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3-10, 3-9, etc.

[0022] When an element or layer is referred to as being "on," "engaged to," "connected to," or "coupled to" another element or layer, it can be directly on, engaged to, connected to, or coupled to the other element or layer, or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to" another element or layer, intervening elements or layers cannot be present. Other words used to describe the relationship between elements should be interpreted in a like manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed elements.

[0023] In this specification, terms such as first, second, third, etc. can be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms can only be used to distinguish one element, component, region, layer, or section from another region, layer, or section. As used in this specification, terms such as "first", "second", and other numerical terms do not imply order or sequence unless clearly indicated by the context. Thus, a first element, component, region, layer, or section described hereinafter can be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0024] In this specification, spatially relative terms such as "inside", "outside", "below", "beneath", "lower", "above", "upper", etc. can be used to facilitate description of the relationship of one element or feature to another element(s) or feature(s) as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device shown is turned over, an element described as "beneath" or "below" another element or feature would then be oriented "above" the other element or feature. Thus, the exemplary term "beneath" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptions used herein are to be interpreted accordingly.

[0025] As shown in FIG. 1, the present technology is depicted in a method of thermal imaging using a heating system 10, and a method of optimizing a preform temperature profile, and particularly a method of using such a system when blow molding a container (not shown) from a preform 12 of a thermoplastic. The system 10 described in more detail herein generally includes a first camera 14, a second camera 16, a third camera 17, and heating means 18.

[0026] With respect to the preform 12, Figure 2 shows an exemplary preform 12 having a long axis O, with an overall shape similar to a test tube. The preform 12 has a neck 20, a shoulder 22, a body 24, and a rounded closed bottom 26. Typically, the neck 20 and shoulder 22 are formed when they enter the system 10, in their final shape, and do not need to be heated or thermally imaged as intended herein. Thus, typically only the body 24 and bottom 26 are heat-treated and thermally imaged by the system 10, although the entire preform 12 may be heated if desired. The tubular body 24 of the preform 12 has a neck 20 whose upper end is closed by a hemispherical bottom 26 and whose lower end is already in the definitive shape of the neck 20 of the container, and an annular shoulder 22 extending radially outward roughly defines the unheated portion of the preform 12 from its heated portion. The preform 12 can be formed from polyester materials such as polyethylene terephthalate (PET) and other polyesters, polypropylene, acrylonitrile esters, vinyl chloride, polyolefins, polyamides, and their derivatives, blends, and copolymers. As shown, the preform 12 has a shape familiar to those skilled in the art, similar to a test tube, generally having a cylindrical cross-section and a length typically about 50% of the resulting container height, or the preform 12 may, if desired, have any shape, length, and be formed from any material. As described herein, the heat treatment performed in system 10 is intended to prepare the preform 12 for conversion by blow molding each preform 12 with gas or liquid to form it into a container.

[0027] In system 10, each preform 12 is provided at the inlet of infeed station E via a magnetic levitation track, rail, or other transport mechanism (not shown). The preforms 12 are then individually placed on a conveyor 28, which transports them through system 10 as detailed below, and finally to the exit S of system 10 for further processing steps 30. As will be described in more detail below, the further processing steps 30 may include transporting the preforms 12 for re-entry to inlet E for additional heating, removal and recycling, or transporting the preforms 12 to a blow molding die loading station (not shown) for molding them into a container. It is understood that the blow molding step may be either a reheated stretch blow molding process using compressed gas, or a liquid blow molding process in which a compressed liquid, which is the final contents of the container, is used to form the container from the preforms 12.

[0028] Each preform 12 is placed on a spindle 32 (as shown in Figure 2) and enters the system 10 (at ambient temperature), and the spindle 30 is allowed to rotate 360° as the preform 12 passes through the system 10. At the entrance E, each preform 12 is inspected and measured by a first camera 14. The camera 14 is a visual inspection camera, but the camera 14 may be an infrared camera or any other camera capable of measuring the desired properties of each preform 12 as described herein. For example, the camera 14 is configured to inspect, measure, transmit, and / or collect data about the preform 12, including, but not limited to, the starting (often ambient) temperature of the preform 12, the material state of the preform 12 (i.e., amorphous vs. crystalline), any inclusions in the preform 12 (i.e., foreign matter), an image of the preform 12 at a desired resolution, and the physical dimensions of the preform 12 (e.g., height, width, diameter). The camera communicates electronically with a computer 34 and / or a process controller (not shown) and / or other data processor (not shown) that can process and / or aggregate images and data from the first camera 14.

[0029] After inspection and measurement by camera 14, each preform 12 is transported by conveyor 28 through a first section 33 of system 10 having a series of heating means 18. The heating means 18 may be, for example, an infrared oven, or any suitable heating means known to those skilled in the art in the blow molding field. Direct and / or indirect (e.g., reflected) thermal energy can be applied by the heating means 18. Multidirectional application of thermal energy can be used, as well as when the preform 12 itself is moved, spun, or rotated relative to various heat radiation sources in the various heating means 18. Any number of heating means 18 can be utilized if desired, but as shown in Figure 1, system 10 includes three heating means 18. As best shown in Figure 2, each heating means 18 comprises five heating elements 36 to facilitate heating of each preform 12 at different heights of the preform 12 along the longitudinal axis O. It is understood that the number of heating means 18 and the heating elements 36 present in the heating means 18, or their operation during a given process, may vary based on the size or specifications of each preform 12, the material properties of each preform 12, etc. The heating means 18 are spaced longitudinally along the conveyor 26 through the system 10 to introduce thermal energy into the preform 12 such that it results in a desired temperature profile that allows for optimization of the distribution of plastic material during the remaining steps in the pre-stretching and blow-molding process. The temperature profile may vary along the longitudinal axis O of each preform 12, or it may define a gradient. Alternatively, the temperature profile may be constant over the length of the preform 12. Furthermore, the temperature profile may vary over the thickness of the preform 12, for example, such that the material on the outside of the preform 12 is at a higher temperature than the material on the inside of the preform 12. The actual temperature profile depends on the specific design of the preform 12, including its shape and material composition, material distribution, and the design of the resulting vessel that will be formed.As each preform 12 passes through the heating means 18, each preform 12 is rotated on its spindle 32 so that it is heated by the heating means 18 until it reaches the second camera 16.

[0030] As shown in Figure 1, the second camera 16 is an infrared camera adapted to inspect and measure the temperature of each preform 12 along the longitudinal axis O of the preform 12 and around its entire circumference. The camera 16 measures the temperature of the preform 12 around its entire circumference along axis O of the preform 12 with a specified and desired number of data points and / or a desired resolution (constrained by the camera 16). For example, the data points correspond to the respective heights of the heating elements 36 and / or the parts of the preform 12 between them, along each angle and / or region between them on the outer circumference of the preform 12. The second camera 16 communicates electronically with a computer 34 or other data processor (not shown) that can process and / or aggregate the thermal property data measured by the camera 16. For example, the computer 34 converts the thermal property data of the preform 12 into a three-dimensional thermal image 38 of each preform 12, as best shown in Figure 3. The computer 34 can then convert the three-dimensional thermal image 38 into a two-dimensional thermal image 40 (also known as a heatmap). Alternatively, the computer 34 may directly convert the thermal property data into a two-dimensional thermal image 40. The image 40 is a representation of the temperature measurements of the preform 12 from approximately 0° to approximately 359°, taken as the preform 12 rotates on the spindle 30, viewed from left to right. In this way, the three-dimensional temperature profile of the preform 12 can be viewed in two dimensions. Furthermore, the temperature profile of the preform 12 can be viewed as a whole or in a desired discrete region along the longitudinal region 42, for example, as shown in Figure 4. As an example, and as best shown in Figure 4, the three-dimensional thermal image 38 can be divided into a desired number of longitudinal regions, such as 359 longitudinal regions corresponding to each angle of the preform 12 rotated around its axis O from approximately 0° to approximately 359°. In this way, the three-dimensional thermal image 38 and specific longitudinal regions 42 of the preform 12 itself can be more easily observed on the two-dimensional thermal image 40 without the need to access and / or rotate the three-dimensional thermal image 38.

[0031] As described above, the temperature of the preform 12 is compiled by the computer 34. Then, as shown in graph 44 of Figure 5, the measured temperatures are plotted against the measurement location on the preform 12. As shown in graph 44, the temperature of the preform 12 at each temperature measurement (x axis) captured by the camera 14 is plotted against the location (x axis) of that measurement on the preform 12. In this way, graph 44, which is a numerical / graphical display of temperature measurements, can be easily compared and directly correlates with the two-dimensional thermal image 40, which is a color-based heatmap.

[0032] By creating a two-dimensional thermal image 40, the temperature measurements of each heated preform 12 can be easily confirmed before the preforms 12 are transferred to the blow molding station and molded into the final container. In some cases, the thermal images 38, 40 and / or graph 44 may show that the preform 12 has "cold regions" 46 or "warm regions" 48. Such regions 48, 48 may rupture (blow out) during blow molding, thus requiring corrective measures during the heating of the preform 12. The exact location of such regions 46, 48 can be precisely located by observing and analyzing the thermal images 38, 40 and / or graph 44, so that corrective measures can be taken to ensure proper heating of the preform 12 to minimize rupture during blow molding into the container. The corrective measures may include one or more adjustments to the processing parameters and settings of the system 10, including adjusting the heating means 16 or specific heating elements 36 to raise or lower the temperature of any part of the preform 12 (e.g., regions 46, 48) as desired, so that subsequent preforms have different acceptable temperature profiles, in order to minimize rupture during blow molding. Additional corrective measures may include, for example, adjusting the spin speed of the spindle 32 on which each preform 12 is placed upward or downward, or increasing or decreasing the residence time of the preform 12 in the system 10 (or the speed of the conveyor 28), and / or increasing or decreasing the cooling airflow in the system 10.

[0033] Once each preform 12 has been inspected and measured by the second camera 16, the conveyor 28 transports each preform 12 to the second part 35 of the system 10 and sends it to a series of additional heating means 50. Like the heating means 18, the heating means 50 may be, for example, an infrared oven, or any suitable heating means known to those ordinarily skilled in the art in blow molding techniques. The heating means 50 can apply direct and / or indirect (e.g., reflected) thermal energy. Multidirectional application of thermal energy can be used as well as the preform 12 itself being moved, spun, or rotated around various heat radiation sources in the various heating means 50. Any number of heating means 50 can be utilized if desired, but as shown in Figure 1, the second part 35 of the system 10 includes three heating means 50. The heating means 50 are similar to those shown in Figure 2, and each heating means 50 comprises five (5) heating elements (not shown) to facilitate heating of each preform 12 at different heights along the longitudinal axis O of each preform 12. It is understood that the number of heating means 50 and the heating elements present in the heating means 50, or their operation during a given process, may vary based on the size or specifications of each preform 12, the material properties of each preform 12, etc. The heating means 50 are spaced longitudinally along the conveyor 28 through the system 10 to introduce thermal energy into the preform 12 that results in a desired temperature profile, enabling optimization of the distribution of plastic material during the remaining steps in the prestretch and blow molding process. The temperature profile may vary along the longitudinal axis O of each preform 12, or it may define a gradient. Alternatively, the temperature profile may be constant over the length of the preform 12. Furthermore, the temperature profile may vary over the thickness of the preform 12, for example, such that the material on the outside of the preform 12 is hotter than the material on the inside of the preform 12. The actual temperature profile depends on the specific design of the preform 12, including its shape and material composition, material distribution, and the design of the resulting container.

[0034] As each preform 12 passes through the heating means 50, each preform 12 is rotated on its spindle 32 and thus heated by the heating means 18 until each preform 12 reaches the third camera 17. As shown in Figure 1, the third camera 17 is an infrared camera adapted to inspect and measure the temperature of each preform 12 along its longitudinal axis O and around its entire circumference. The camera 17 measures the temperature of the preform 12 along its axis O and around its circumference with a defined desired number of data points and / or a desired resolution (constrained by the camera 17). For example, the data points may correspond to the portions of the preform 12 at each height of the heating element 36 and / or in the region between each angle and / or in the region around the preform 12. The third camera 17 electronically communicates with a computer 34 and / or a process controller and / or other data processor (not shown) which can process and / or aggregate the thermal property data measured by the third camera 17. For example, the computer 34 converts the thermal characteristics data of the preform 12 into images similar to those shown in Figures 3 to 5 with respect to the second camera 16, as described herein.

[0035] During use, images and / or information acquired from the first camera 14 are processed by the computer 34 to determine the appropriate heat treatment for each preform 12 receiving heat from the heating means 18. For example, the first camera 14 can identify individual preforms formed from different materials, or individual preforms having different sizes corresponding to containers having different volumes. Thus, each preform 12 can request its own specific heat treatment from the heating means 18, and / or, the first camera 14 can detect an unacceptable number of inclusions or other unacceptable problems for a particular preform and signal to the system 10 via the computer 34 or process controller to reject that preform and remove it for recycling or destruction. Once each preform 12 has received heat treatment from the heating means 18, data about each preform 12 is collected by the second camera 16. The computer 34 compares the data of each preform 12 received from the first camera 14 with the data received from the second camera 16 to confirm that the heat treatment was appropriate and acceptable for the given specifications of the preform 12 (e.g., dimensions and / or material). In this way, it is possible to ensure that each preform 12 enters the second part 35 of the system for additional heat treatment by the heating means 50 with a consistent temperature and / or temperature profile, regardless of the ambient conditions of the system 10 or the starting conditions of the preform 12 when entering the inlet E of the system 10.

[0036] The computer 34 or process controller may adjust the first part 33 of the system 10 so that subsequent preforms 12 of similar specifications receive appropriate heat treatment, for example, by increasing or decreasing the intensity of the heating means 18, adjusting the spin speed of the spindle 32 on which each preform 12 is placed to increase or decrease speed, increasing or decreasing the residence time of the preforms 12 in the first part 33 of the system 10 (i.e., the speed of the conveyor 28), and / or increasing or decreasing the cooling airflow in the first part 33 of the system 10. The computer 34 and / or process controller may adjust the first part 33 of the system 10 as needed based on a comparison of images from cameras 14, 16 and / or data from cameras 14, 16 regarding each preform 12. By ensuring that the heat treatment of each preform 12 is appropriate and acceptable before the preform 12 is subjected to blow molding (i.e., further processing step 30), blowout of preforms (single or double) 12 can be minimized, resulting in cost savings.

[0037] Furthermore, once each preform 12 undergoes a second heat treatment in the second section 35, the images 38, 40 and / or graphs 42 generated from the third camera 17 for each preform 12 may be compared by the computer 34 to a catalog, database, table, or collection of images (e.g., heatmaps) and / or data points and / or graphs corresponding to a predetermined acceptable temperature profile (individually or collectively, the "standard temperature profile") for each preform 12 of a particular material or dimension. In this way, the computer 34 can compare the data of each preform 12 passing through the third camera 17 to the acceptable temperature profiles of preforms of similar dimensions and / or material to optimize the temperature profile of each preform 12, thereby ensuring that the preform 12 does not blow out during the further processing step 30.

[0038] This comparison, performed after each preform 12 has been measured by the third camera 17, may take the form of a comparison between an acceptable thermal image of a given preform with defined dimensions and / or material and a thermal image of each preform 12 processed in the system 10, such as a two-dimensional image 40 from the third camera 17; or a comparison between acceptable aggregated thermal data from the third camera 17 and aggregated data of each preform 12 processed in the system 10. Alternatively, the comparison may take the form of a comparison between an acceptable graph corresponding to an acceptable temperature profile and each graph similar to a graph 42 from the data from the third camera 12 of each preform 12 processed in the system 10.

[0039] By comparing the thermal data and / or images of each preform 12 processed within System 10 with a known, constant, acceptable set of thermal data and / or images, the thermal treatment applied to the preform can be easily reproduced anywhere in the world, regardless of the ambient temperature of System 10, the ambient conditions of System 10, or the starting temperature or conditions of the preform. Regardless of where System 10 is located, each processed preform 12 is observed and identified by a first camera 14, subjected to appropriate thermal treatment corresponding to the material and / or dimensions of the preform 12 by heating means 18 in a first section 33; a temperature profile of the preform 12 is acquired by a second camera 16 to ensure its starting temperature is acceptable before entering a second section 35; subjected to appropriate thermal treatment by heating means 50 in the second section 35; and then its temperature profile is compared by a computer 34 to an acceptable temperature profile. After comparison, each of the preforms 12 is transported for blow molding into a container, conforming to a known acceptable temperature profile (or conforming within an acceptable deviation therefrom), or each of the preforms 12 deviates from a known acceptable temperature profile and is transported for additional heat treatment or rejected and recycled (collectively, further processing step 30).

[0040] By comparing each preform 12 with known acceptable standard data, it is possible to verify that each preform 12 has received acceptable heat treatment by the system 10 before being transported to the exit S, thereby minimizing blowout during blow molding of each preform 12. Unacceptable preforms can be discarded or reheated. For preforms 12 that are unacceptably heated as determined by comparison with images generated from a third camera 17, the computer 34 or process controller may adjust the second part 35 of the system 10 so that subsequent preforms 12 of similar specifications receive appropriate heat treatment, for example, by increasing or decreasing the intensity of the heating means 50, adjusting the spin speed of the spindle 32 on which each preform 12 is placed to increase or decrease, or increasing or decreasing the residence time of the preforms 12 in the second part 35 of the system 10 (i.e., the speed of the conveyor 28), and / or increasing or decreasing the cooling airflow in the second part 35 of the system 10.

[0041] Once each preform 12 is deemed acceptable, each preform 12 is transported from each preform 12 to one or more systems (not shown) for blow molding a container. In particular, the blow molding system may include a mold (not shown) configured to receive each preform 12, and means for supplying a pressurized fluid to the preform received in the mold to inflate the preform into a container that conforms to the inner surface of the mold. The pressurized fluid may be a gas (e.g., air) or a liquid (e.g., the product intended to remain in the resulting container). In a process where each preform 12 is formed from a different material and / or has different dimensions, the transport mechanism may selectively transport each preform 12 to different blow molding systems for forming a number of containers. In other words, this technology further considers the sequential manufacturing of various containers derived from preforms heated to different temperature profiles, which include preforms of different structures (e.g., preforms formed of different sizes, shapes, thicknesses, different polymers or polymer combinations, layers, etc.) that require different comparisons with different heating regimens and different known acceptable temperature profiles in preparation for blow molding to the resulting containers.

[0042] The benefits and advantages of this technology may include the following: juxtaposition and weighing of preforms of multiple sizes and materials within the same system (e.g., system 10). Selective transfer and controlled dispensing of preforms between and from multiple heating means provide a unique method for handling different preforms and enable flexible stock unit (SKU) management. For example, the system may include one or more barcode readers to track the loading position of preforms as they enter the system from one or more loaders and undergo specific movements through one or more heating means or a path that includes portions having different speeds and / or residence times. The ability to flexibly handle mixtures of multiple types of preforms further enables continuous or high-throughput blow molding.

[0043] Exemplary embodiments are provided to ensure that the disclosure is thorough and fully conveys its scope to those skilled in the art. Numerous specific details are given, including examples of specific components, devices, and methods, to provide a complete understanding of the embodiments of the disclosure. It will be apparent to those skilled in the art that these specific details are not required, that the exemplary embodiments may be embodied in many different forms, and that neither should be construed as limiting the scope of the disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known techniques are not described in detail. Equivalent changes, modifications, and variations of some embodiments, materials, compositions, and methods can be made within the scope of the Art, with substantially similar results.

Claims

1. A method for heating a preform, The steps include preparing multiple preforms suitable for blow molding, The steps include: inspecting each preform to identify at least the material forming the preform; The steps include heating each preform, The steps include measuring the temperature of at least a portion of each preform along the longitudinal axis of each preform, The step of further heating each preform, Further measurement steps include measuring the temperature of at least a portion of each preform along the longitudinal axis of each preform and generating a temperature profile, A step of comparing the temperature profile from the further measurement step with the standard temperature profile of each of the plurality of preforms, Based on the comparison step, a step of blow molding a preform having an acceptable temperature profile, Based on the comparison step, the preforms that do not have an acceptable temperature profile are recycled, or based on the comparison step, the preforms that do not have an acceptable temperature profile are reheated. A method for providing this.

2. The method according to claim 1, further comprising a step of optimizing the further heating step so that the subsequent preform is heated to an acceptable temperature based on the comparison step and the recycling or reheating of the preform is minimized.

3. The method according to claim 2, wherein the optimization step is to adjust, by comparison, at least one of the intensity of the heating means in the further heating step, the spin speed of each preform in the further heating step, and the residence time of the preform in the further heating step.

4. The method according to claim 1, further comprising the step of aggregating the measured temperatures of at least some of the preforms during the further measurement step.

5. The method according to claim 4, further comprising the step of converting the aggregated measured temperatures into a three-dimensional thermal image representing the measured temperatures of at least a portion of the preform.

6. The method according to claim 5, wherein in the further measurement step, the aggregated temperatures are converted into a two-dimensional thermal image representing a portion of the preform measured around the preform along the longitudinal axis of the preform.

7. The method according to claim 6, wherein the two-dimensional thermal image is a heat map.

8. The method according to claim 7, wherein the heat map represents measured values ​​around the preform from 0° to 359° for at least a portion of the preform.

9. The method according to claim 6, wherein during the heating step and the further heating step, the preform is rotated at least 360° around its longitudinal axis.

10. The method according to claim 4, further comprising the step of converting the aggregated temperatures into a graph image representing the temperatures of at least a portion of the preform relative to the measurement location.

11. The method according to claim 1, wherein the inspection step is performed by a first camera, the measurement step is performed by a second camera, and the further measurement step is performed by a third camera.

12. The method according to claim 11, wherein the first camera is an external inspection camera.

13. The method according to claim 11, wherein each of the second camera and the third camera is an infrared camera.

14. The method according to claim 1, wherein not all of the plurality of preforms are formed from the same material.

15. A method for heating a preform, The steps include preparing multiple preforms suitable for blow molding, The steps include: inspecting each preform to identify at least the material forming the preform; The steps include heating each preform, The steps include measuring the temperature of at least a portion of each preform along the longitudinal axis of each preform, The step of further heating each preform, Further measurement steps include measuring the temperature of at least a portion of each preform along the longitudinal axis of each preform and generating a temperature profile, A step of comparing the temperature profile from the further measurement step with one standard temperature profile of the plurality of preforms, Based on the comparison step, a step of blow molding a preform having an acceptable temperature profile, Based on the comparison step, the preforms that do not have an acceptable temperature profile are recycled, or based on the comparison step, the preforms that do not have an acceptable temperature profile are reheated. A method for providing this.

16. The further measurement step includes a step of aggregating the measured temperatures of at least some of the preforms, The steps include converting the aggregated measured temperatures into a three-dimensional thermal image representing the measured temperatures of at least a portion of the preform, The method according to claim 15, further comprising:

17. A method for heating a preform, The steps include preparing multiple preforms suitable for blow molding, The steps include: inspecting each preform to identify at least the material forming the preform; The steps include heating each preform, The steps include measuring the temperature of at least a portion of each preform along the longitudinal axis of each preform, The step of further heating each preform, Further measurement steps include measuring the temperature of at least a portion of each preform along the longitudinal axis of each preform and generating a temperature profile, The further measurement step includes a step of aggregating the measured temperatures of at least some of the preforms, The steps include converting the aggregated measured temperatures into a three-dimensional thermal image representing the measured temperatures of at least a portion of the preform, The steps include further converting the three-dimensional thermal image into a two-dimensional thermal image representing a portion of the preform measured around the preform along the longitudinal axis of the preform, The step of comparing the two-dimensional thermal image obtained from the above conversion step with a standard two-dimensional thermal image corresponding to one of the plurality of preforms, Based on the comparison step, a step of blow molding a preform having an acceptable temperature profile, Based on the comparison step, the preforms that do not have an acceptable temperature profile are recycled, or based on the comparison step, the preforms that do not have an acceptable temperature profile are reheated. A method for providing this.

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