The present disclosure relates to an injection molding device and more specifically to an injection molding device having an improved index plate design and improved ejector system.
To produce molded products there are various injection molding technologies and techniques available including, but not limited to, transfer molding, rotary table molding, core back molding, and index plate molding. Such molding techniques are well known in the oral care industry for producing toothbrushes, interdental cleaners, and the like.
In many current molding device designs (not shown), index plates may use cores or pins to provide the necessary coupling strength between the first component of the finished part and the index plate for transfer between different sets of cavities. Furthermore, it is common in the art to utilize a straight parting line between the index plate and the bottom mold.
Due to the fact that the handle part is permanently fixed to the insert plate it is normally not possible to have the second component overmolded onto both sides of the product handle (e.g., both above and below the parting line between the index plate and the upper mold). In such situations, the only way to gain access to the underside of the handle is to implement a core back solution into the index plate. Such solutions are extremely complicated and increase mold costs tremendously. Still further, once the costs are incurred, the resulting design capabilities are very restricted.
In one embodiment, the device includes an index plate molding device configured to produce a multi-component part including an injection mold having an injection parting surface, an ejection mold having an ejection parting surface in selective contact with the injection parting surface to form an ejection parting line therebetween, an index plate movable relative to the injection mold and the ejection mold, where the index plate includes an index parting surface in selective contact with the injection parting surface to form an index parting line therebetween. The index plate molding device also includes a first mold cavity at least partially defined by the index plate, where the first mold cavity is configured to produce a first component of the multi-component part, and a second mold cavity at least partially defined by the index plate, where the second mold cavity is configured to overmold a second component onto the first component of the multi-component part, and where the index plate is shaped such that the outer surface of the first component of the multi-component part is available for overmolding on both sides of the index parting line when the first component is coupled to the index plate.
In another embodiment, an index plate molding device including an injection mold having an injection parting surface, an ejection mold having an ejection parting surface in selective contact with the injection parting surface to form an ejection parting line therebetween, where the ejection mold includes an ejection-intermediate surface, and where the ejection mold is movable relative to the injection mold about an ejection axis, an index plate having an index surface in selective contact with the injection surface to form an index parting line therebetween, where the index plate includes an index-intermediate surface in selective contact with the ejection-intermediate surface to form an intermediate parting line therebetween, and where the index plate is movable relative to the injection mold about the ejection axis, and a mold cavity defined by the injection mold, the ejection mold, and the index plate, and where the intermediate parting line is non-linear as it passes through the mold cavity.
In another embodiment, the device provides an index plate molding device including, an injection mold having an injection parting surface, an index plate having an index parting surface in selective contact with the injection parting surface to form an index parting line therebetween, where the index plate defines a channel, an ejection mold having an ejection parting surface in selective contact with the injection parting surface to form an ejection parting line therebetween, where at least a portion of the second mold portion is positioned within the channel of the index plate, and a mold cavity defined by the first mold portion, the second mold portion, and the index plate.
In another embodiment, an index plate molding device including, an injection mold having an injection parting surface, an ejection mold having an ejection parting surface in selective contact with the injection parting surface to form an ejection parting line therebetween, an index plate having an index parting surface in selective contact with the injection parting surface to form an index parting line therebetween, where the index plate includes a first locking surface and a second locking surface, and where the first locking surface is substantially parallel to and facing opposite to the second locking surface, and a mold cavity defined by the injection mold, the ejection mold, and the index plate.
In another embodiment, the device provides a method of forming a multi-component part using an index plate molding device having an injection mold with an injection parting surface, an ejection mold with an ejection parting surface in selective contact with the injection parting surface to form an ejection parting line therebetween, and an index plate having an index parting surface in selective contact with the injection parting surface to form an index parting line therebetween. The method including positioning the injection mold, the ejection mold, and the index mold to form a first mold cavity defined therebetween, injecting a first material into the first mold cavity to form a first component of the multi-component part, allowing the first material to cool such that the first component is frictionally coupled to the index plate so that the first component is available for overmolding on both sides of the second parting line, re-positioning the index plate, the injection mold, and the ejection mold to form a second mold cavity having a second shape than the first mold cavity and position at least a portion of the first component therein, and overmolding a second material onto the first component.
Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the test tube holder are explained in detail, it is to be understood that the injection molding device is not limited to the details set forth in the following description or illustrated in the accompanying drawings. The injection molding device is capable of supporting other implementations and of being practiced or of being carried out in various ways.
For the purposes of this application, the multi-component interdental cleaner 30 includes a first component 34 having a handle portion 38, and a tip portion 42 extending from the handle portion 38 (see
The interdental cleaner 30 also includes a second component 46 overmolded onto the outer surface 50 of the first component 34 in one or more locations. In the illustrated embodiment, the second component 46 completely encompasses the tip portion 42 of the first component 34 to form a cleaning part 54 (see
Illustrated in
Illustrated in
Best illustrated in
In the illustrated embodiment, the body 62 of the ejection mold 14 is formed from a plurality of plates 90a-d, each coupled to a common base 94. However, in alternative embodiments, the ejection mold 14 may be formed from a single piece of material (not shown).
Illustrated in
The injection mold 18 defines a first set of depressions 122 and a second set of depressions 128, each formed into the injection parting surface 110 of the body 108 and configured to at least partially define the first set of cavities 26a and the second set of cavities 26b, respectively. In the illustrated embodiment, the first set of depressions 122 are shaped differently than the second set of depressions 122.
During operation, the injection mold 18 of the molding device 10 is movable with respect to the ejection mold 14 between a closed position (see
Illustrated in
Best illustrated in
In the illustrated embodiment, the intermediate parting line 78 substantially corresponds with the outer contour of the handle portion 38 of the first component 34 being slightly offset inwardly therefrom. More specifically, the intermediate parting line 78 is substantially an equal distance from the periphery of the handle portion 38 of the first component 34 for a majority of its path through the first component 34. Furthermore, the protrusions 106 and channels 112 of the index plate 22 extend substantially perpendicular to the ejection axis 138. As shown in
The index plate 22 also defines first and second sets of depressions 146, 150, each at least partially defining either the first set of cavities 26a or the second set of cavities 26b depending upon the orientation of the index plate 22 with respect to the upper and bottom molds 14, 18 (described below). In the illustrated embodiment, the first and second sets of depressions 146, 150 are substantially similar in size and shape and configured to support the first component 34 of the multi-component part such that the first component 34 is available for overmolding on both sides of the index parting line 78 when the first component 34 is coupled to the index plate 22.
As shown in
The size and shape of the first and second sets of depressions 146, 150 at least partially determine the areas of the outer surface 50 of the first component 34 placed in direct contact with the index plate 22 after the first component 34 is formed. Since the areas of the first component 34 in direct contact with the index plate 22 remain coupled to the index plate 22 throughout the duration of the molding process, those areas cannot be overmolded by the second component 46. As such, the size and shape of the depressions 146, 150 at least partially determine the areas of the first component 34 that are available for overmolding (e.g., areas that are not in direct contact with the index plate 22). In the illustrated embodiment, the substantially “U” shaped contour of the depressions 146, 150 places only the periphery of the handle portion 38 in direct contact with the index plate 22. As such, the interior areas on both sides of the handle portion 38 (e.g., above and below the index parting line 78) are available for overmolding by the second component 46. Stated differently, the first component 34 is coupled to the index plate 22 such that the outer surface 50 of the first component 34 is available or overmolding both above and below the index parting line 78.
Best illustrated in
In the illustrated embodiment, the first and second locking surfaces 154 of the index plate 22 include two surfaces oriented substantially parallel to and facing opposite one another. Each locking surface 154 is also substantially parallel to the ejection axis 138 (see
While the illustrated embodiment illustrates the first and second locking surfaces 154 being formed as a single “U” shaped surface 154, it is to be understood that more or different shaped locking surfaces may be used so long as thermal shrinkage of the corresponding component causes a compressive force to be applied thereto. For example, two or more opposing surfaces or pegs positioned on either side of the part's center of mass CM may be used (not shown). In still another example, a circular surface centered about the center of mass CM may be used.
During use, the index plate 22 is movable with respect to the ejection mold 14 and the injection mold 18, both translationally and rotationally. More specifically, the index plate 22 is movable axially along the ejection axis 138 between a set position (see
The molding device 10 also includes a first ejection system (not shown) coupled to the bottom mold 14 and in operable communication with the second set of cavities 26b. The first ejection system is configured to eject the finished set of interdental cleaners 30 from the second set of cavities 26b after the molding process is complete. The first ejection system may be driven by compressed air, a spring, an actuator, and the like.
The molding device 10 also includes a second ejection system (not shown) coupled to the upper mold 18 and in operable communication with second set of cavities 26b. The second ejection system is configured to press against the finished interdental cleaners 30 as the mold opens to assure the interdental cleaner 30 does not stick the injection mold 18. The second ejection system may be driven by compressed air, a spring, an actuator, or the like.
The molding device 10 also includes a third ejection system 158 coupled to the ejection mold 14 and in operable communication with the first set of cavities 26a (see
During the molding process, the molding device 10 begins with the index plate 22 in the set position translationally and the first orientation rotationally. As such, the index plate 22 is substantially aligned with the ejection mold 14 and rotationally oriented so that the first depressions 146 of the index plate 22 are aligned with the first depressions 82 of the bottom mold 14. Likewise, the second depressions 150 of the index plate 22 are aligned with the second depressions 86 of the ejection mold 14. The molding device 10 also begins with the injection mold 18 in the closed position (see
With the molding device 10 initialized, the molding process begins with a first injection step. During the first injection step, the molding device 10 injects a pre-metered amount of molding material (e.g., PP) into each of the first cavities 26a via an injection point (not shown). As the molding material enters each cavity 26a, the material fills the volume forming the first component 34 therein. The first component 34 then begins to cool and solidify, causing the first component 34 to thermally contract in size and apply compressive forces C against the locking surfaces 154 of the index plate 22 (see
Once the first component 34 of the interdental cleaner 30 has sufficiently cooled, the injection mold 18 moves to the open position along the ejection axis 138 (described above). With the mold open, the index plate 22 moves axially away from the set position and toward the actuated position along the ejection axis 138 (see
As the index plate 22 moves from the set position toward the actuated position, the first component 34 remains coupled to the index plate 22 through a combination of the holding force provided by the area of the first component 34 in direct contact with the index plate 22 and the compressive force exerted against the locking surfaces 154. As such, the index plate 22 and the first component 34 move together as a unit.
After the index plate 22 enters the actuated position, the index plate 22 rotates about the ejection axis 138 from the first position and toward the second position. By doing so, the index plate 22 carries the first components 34 out of alignment with their corresponding first cavities 26a and into alignment with a corresponding one of the second set of cavities 26b. Simultaneously, the empty second set of depressions 150 from a previously completed cycle moves into alignment with the first set of cavities 26a.
With the index plate 22 in the second position, the index plate 22 returns to the set position (e.g., axially along the ejection axis 138) thereby placing the index plate 22 back into alignment with the ejection mold 14. The injection mold 18 then returns to the closed position (e.g., axially along the ejection axis 138) thereby enclosing each of the first components 34 within a corresponding one of the second set of cavities 26b (see
With the first components 34 positioned within the second set of mold cavities 26b, the molding device 10 then undergoes the second injection step. During the second injection step, the molding device 10 injects a pre-metered amount of a second molding material (e.g., TPE) into each of the second cavities 26b. As the molding material enters each cavity 26b, the material fills the void formed between the first component 34 and the cavity 26b, allowing the second component 46 to be overmolded onto the outer surface 50 of the first component 34. In particular, the second component 46 may be overmolded onto any area of the outer surface 50 of the first component 34 not in direct contact with the index plate 22, including both sides of the handle 38 (e.g., on both sides of the index parting line 78). In some embodiments, the second injection material is overmolded onto the injection site of the first component 34 (e.g., the position on the first component 34 that corresponds with the location where the first material entered the first set of mold cavities 26a) to cover the injection site of the first component 34 such that it is not visible in the final product.
Once the finished part has sufficiently cooled, the injection mold 18 moves into the open position and the finished part 30 is ejected from the cavity 26b for subsequent collection. The molding device 10 is then ready to reset to the initial start position and begin the cycle anew.
The present application claims priority to U.S. Patent Application No. 62/482,167, filed Apr. 5, 2017, the entire contents of which are hereby incorporated by reference.
Number | Date | Country | |
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62482167 | Apr 2017 | US |