Patent Application
20210283822
Some embodiments may generally relate to blow molding including, for example, stretch blow molding. More specifically, certain embodiments may relate to an apparatus and method for fixing a preform in stretch blow molding.
In general, blow molding is a molding process used in the manufacturing industry to create hollow objects made of plastic. Similar to other molding processes, blow molding may involve the use of heated, liquid material that is injected into a mold cavity under pressure. In certain examples, blow molding is a process in which heated plastic is blown into a mold cavity to create a hollow object. The defining characteristic of blow molding is that it is used to create hollow objects. During this process, raw plastic may first be heated. After the plastic is heated, it may be formed into a parison, and the parison may be secured to the top of the mold. Once secured, air may be blown down into the plastic parison, thereby stretching it across the interior walls of the mold cavity.
Blow molded plastic containers, especially stretch blow molding containers are widely used for water, mineral water, carbonated beverage, beer, and various other liquid products such as detergent, shampoo, cosmetics, and more. When stretch blow molding a container, before the container is finally produced, injection molding a preform is implemented. The preform may be much smaller than the final container product, and may include the opening unit corresponding to the mouth of the container, and the cylindrical body unit. The opening unit may include the open end for hermetic sealing or a combining means with a cover.
After injection molding a preform, the preform may be heated and stretch blown in an axial direction, and blown in a transverse direction. The preform may be fully blown inside a blow mold into a container, of which the upper end is cut and the finished container is produced. A reason why the upper end of the container is blown in the blow mold is because a conventional neck jig grips a neck of the preform after injection molding a preform to move the injection molded preform to the stretch blow mold, and entails scrapes of the gripped part of the neck. This therefore may result in cutting the scraped part.
Furthermore, in a general apparatus for injection molding a multilayer article, a conventional multi-injection machine may be needed. The multi-injection machine may include multi-injection units that include a main injection unit and a sub-injection unit. These injection units may inject two different types of resin. For instance, the main injection unit may inject a first resin and the sub-injection unit may separately inject a second resin.
To prevent the scrape from damaging the finished container, additional area on the top of the neck may be added for the neck jig to grip and to be cut after blow molding. Alternatively, an additional neck ring may be formed on the neck for the preform to be fixed on the blow mold.
In view of the challenges with conventional injection molding machines, there is a need to provide an improved injection blow molding procedure to minimize or eliminate the waste of resin and cutting equipment. There is also a need to eliminate the use of conventional fixing means such as a neck jig that grips a neck of the preform and a neck ring that makes the preform become fixed to the blow mold tighter. In addition, there is a need to provide a pressing type fixing unit that is inserted into the preform, presses the preform in an outward direction, and fixes the preform on the blow mold tighter.
One embodiment may be directed to an apparatus for fixing a preform in stretch blow molding. The apparatus may include a mold body configured to accommodate the preform. The apparatus may also include a pressing type fixing apparatus inserted into the preform and configured to press the preform in an outward direction and fix the preform to the mold body. The apparatus may further include a gas injection apparatus configured to inject gas into the preform.
Another embodiment may be directed to a method for fixing a preform in stretch blow molding. The method may include disposing the preform in a mold body, the mold body including a housing. The method may also include inserting a pressing type fixing unit into the preform to fix the preform to the mold body. The method may further include injecting gas from a gas injection apparatus into the preform along a gas route. In addition, the method may include inserting a stretch rod through a moving route of the pressing type fixing unit during the gas injection. The method may also include pressurizing, with the stretch rod, a lower body of the preform in a longitudinal direction. The method may further include cutting the preform at an upper neck after gas injection is completed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the detail description serve to explain the principles of the invention. In the drawings:
It will be readily understood that the components of certain example embodiments, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. The following is a detailed description of some embodiments for synthesizing dry gels and the corresponding activated carbon gels using a thermal reaction to produce dry gels without the use of catalysts or non-water solvents.
The features, structures, or characteristics of example embodiments described throughout this specification may be combined in any suitable manner in one or more example embodiments. For example, the usage of the phrases “certain embodiments,” “an example embodiment,” “some embodiments,” or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment. Thus, appearances of the phrases “in certain embodiments,” “an example embodiment,” “in some embodiments,” “in other embodiments,” or other similar language, throughout this specification do not necessarily all refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more example embodiments.
Additionally, if desired, the different functions or steps discussed below may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the described functions or steps may be optional or may be combined. As such, the following description should be considered as merely illustrative of the principles and teachings of certain example embodiments, and not in limitation thereof.
According to certain embodiments when blow molding a preform, a pressing type fixing unit may be inserted into the preform, which presses the preform in an outward direction. As such, certain embodiments may be developed for stretch blow multilayered preforms of higher than five hundred grams per cavity made of resins with lower stretch properties such as glycol modified polyethylene terephthalate (PETG). In addition, certain embodiments may provide an apparatus for fixing a preform in stretch blow molding that may include a mold body accommodating the preform in its inside. The apparatus may also include a pressing type fixing unit that is inserted into the preform, and presses the preform in the outward direction, and then fixes the preform to the mold body.
As described above, an apparatus for fixing a preform in stretch blow molding may be provided. Such an apparatus can eliminate conventional fixing means such as a neck jig that grips a neck of the preform and a neck ring, which makes the preform fixed to the blow mold tighter. As such, conventional methods unnecessarily waste resin and require additional use of cutting equipment. Moreover, when using the neck jig, which grips the additional area on the top of the neck of the multilayer preform, cutting the additional area from the neck after blow molding can expose the intermediary layer of the multilayer container. This may result in imperfections of the barrier function of the intermediary layer.
According to certain embodiments, a protrudent fixing unit may be provided. The protrudent fixing unit may be formed around the inscribed circle of the opening unit of an apparatus for fixing a preform in stretch blow molding. This may ultimately make the preform fixed to the blow mold in a tighter manner. In other embodiments, the pressing type fixing unit may include a moving route through which a stretch rod may move in a longitudinal direction. This may facilitate gas injection into the preform, and make the stretch blow molding easier. In addition, as a gas injection apparatus is integrally formed in the pressing type fixing unit, conventional gas injection means and operating tools may no longer be necessary.
According to an embodiment, the mold body 100 may include a housing 110. The housing 110 may include a molding space 110A inside the housing 110. The mold body 100 may also include an opening 113 that is formed in an upper side of the housing 110. In addition, the mold body 100 may include a protrudent fixing structure 111 formed around an inner surface of the opening 113. According to an embodiment, the protrudent fixing structure 111 may make the preform P be fixed to the blow mold tighter.
In certain embodiments, the preform P may be accommodated in the housing 110. Further, the neck of the preform P may be fixed to the inscribed circle of the opening 113. More specifically, the upper neck (
In certain embodiments, the multiple fixing pieces 210 may be composed of at least two fixing pieces so that the multiple fixing pieces 210 may be composed of at least two fixing pieces so that the multiple fixing pieces 210 can press the preform P with fully strong force to the inscribed circle of the opening 113. Specifically, in an embodiment, the multiple fixing pieces 210 may be inserted into the preform P, and press the preform P in an outward direction. The multiple fixing pieces 210 also fix the preform P to the mold and body unit 100.
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According to certain embodiments, the preform P may be accommodated in the housing 110, and the neck of the preform P may be fixed to the inscribed circle of the opening 113. For instance, as previously noted, the upper neck of the preform P in which a screw thread is formed, may be exposed to the outside of the housing 110, and the lower neck below the screw thread may be fixed to the inscribed circle of the opening 113 with the pressing force of the pressing type fixing apparatus 200.
According to certain embodiments, during the gas injection process by the gas injection apparatus 500, the stretch rod 300 may be inserted together through the moving route 240 formed with the pressing type fixing apparatus 200. In addition, the stretch rod 300 may pressurize the lower body of the preform P in the longitudinal direction, thereby facilitating the stretch blow molding. More specifically, after closing the opening 113 with the sealing cap 510, the gas injection apparatus 500 may inject gas into the inside of the preform P, and the injected gas may flow through the neck of the preform P thereby shaping a container product according to the molding space 110a of the mold body 100. As previously noted, during this time, the stretch rod 300 may pressurize the lower body of the preform P in the longitudinal direction, thus facilitating stretch blow molding.
According to an embodiment, the gas injected from the gas injection apparatus may be attached to the housing. According to another embodiment, the gas injection apparatus may include a sealing cap. In an embodiment, the method may further include forming a screw thread at the upper neck of the preform. In another embodiment, the method may include exposing the upper neck to an exterior of the mold body. In a further embodiment, the method may include disposing a lower neck of the preform in an interior space of the mold body. According to an embodiment, the method may also include forming a protrudent fixing unit around an inscribed circle of an opening unit formed on an upper side of the housing. According to another embodiment, the gas may be injected from a gas injection tube attached to the pressing type fixing apparatus.
Certain embodiments described herein provide several technical improvements, enhancements, and/or advantages. In some example embodiments, it may be possible to provide an apparatus for fixing a preform in stretch blow molding that may prevent unnecessary waste of resin and additional use of cutting equipment, which may result in reducing the cost of production and reducing working hours. Certain embodiments may also provide a pressing type fixing apparatus that is inserted into the preform, presses the preform in an outward direction, and fixes the preform on the blow mold tighter. According to other embodiments, it may be possible to eliminate conventional fixing means such as a neck jig, which grips a neck of the preform and a neck ring that makes the preform fixed to the blow mold tighter. In this manner, it may be possible to prevent unnecessary waste of resin and additional use of cutting equipment. Additionally, certain embodiments may prevent imperfections occurring in the barrier function of the intermediary layer of the multilayer container. In other embodiments, a gas injection apparatus may be integrally formed in the pressing type fixing apparatus, which may eliminate conventional gas injection means and operating tools.
One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these example embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of example embodiments.
