WO2018107274A1

WO2018107274A1 - Method of producing molded article and apparatus for executing same

Info

Publication number: WO2018107274A1
Application number: PCT/CA2017/051400
Authority: WO
Inventors: Christophe Halter; Douglas James Weatherall; Udo Schwarzkopf
Original assignee: Husky Injection Molding Systems Ltd.
Priority date: 2016-12-15
Filing date: 2017-11-23
Publication date: 2018-06-21

Abstract

There is disclosed an injection molding apparatus for producing a flip top closure having a body that includes a base and a lid connected by a hinge. The injection molding apparatus comprises: an injection unit; a mold fluidly coupled to the injection unit, the mold defining a mold cavity for producing the flip top closure, the mold cavity having: a base defining portion for defining the base, a lid defining portion (or defining the lid, and a hinge defining portion for defining the hinge; the injection unit being configured to inject the molding material into the mold cavity via an injection point; and a heater placed adjacent to the hinge defining portion, the heater configured for heating of at least a portion of the hinge defining portion to a continuous temperature during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity.

Description

METHOD OF PRODUCING MOLDED ARTICLE AND APPARATUS

FOR EXECUTING SAME

FIELD This application relates to an injection molding process in general and, more specifically, to a method of producing a molded article and an apparatus for executing same.

BACKGROUND

Injection molding is a process by which a molding material is injected into a mold and then cooled to form a solid molded article. A molding material, such as, for example, polyethylene terephthalate (PET) is placed in an injection unit, which heats the molding material into a molten, flowable state. Molten molding material is then conveyed through a distribution network, often referred to as a "hot runner", and delivered to one or more mold cavities through one or more associated nozzles.

Various articles can be produced using the molding process. Examples include but are not limited to: a preform for subsequent blow molding into a final shaped container for a beverage; a closure for such a container; a thin- walled container for food items and the like. Some of the molded articles are produced using a single molded material - such as a preform for a carbonated soft drink, as an example. Other molded articles are produced using two or more materials. For example, a given molded article can be produced from two different resins or from two forms of the same resin (such as virgin and recycled). A particular type of the molded article that can be produced using the injection molding process is a flip top closure. With reference to Figure 1, there is depicted a prior art flip top closure 100. The flip top closure 100 comprises a base 102 and a lid 104, joined therebetween by a hinge 106. Exact shape of the base 102, the lid 104 and the hinge 106 will vary based on the specific technical requirements for the flip top closure 100. Typically the lid 104 is smaller and, thus, lighter than the base 102. This is due to the fact that the base 102 is a structural element usually made to push onto a bottle (not depicted) and needs thick walls. The lid 104, on the other hand, is required only to provide closing for a product opening (not numbered) and is most commonly thin and light. l US patent application 2004/0149733 discloses shaped resistive heaters, uses thereof, and methods for their fabrication. The heaters are shaped such that they can conform to all or part of an object, e.g., an injection mold. The heaters may be permanently bonded to the object, or they may be adjacent to the object but not adhered, having the advantage of being removable and replaceable. The heaters include an electrically resistive element, which is, for example, a plate, a wire coil, or a deposited layer. Exemplary resistive elements are fabricated by thermal spray.

US patent application 2006/0246166 discloses an injection molding system (10) that generally includes a molding device (100), a mold controller (200), and a negative pressure apparatus (300). The molding device defines a molding cavity (160) and a plurality of cooling channels (110) therein and has a plurality of heating elements (120). The heating elements are used for heating the molding cavity to a determined temperature. A cooling medium is supplied in the cooling channels to cool the molding cavity. The negative pressure apparatus is used for keeping the cooling channels in a negative pressure state, thereby improving the fluidity of the cooling medium during heat removal and avoiding leaving a portion of the cooling medium in the cooling channels during heating. Accordingly, the negative pressure apparatus can effectively decrease the heating and cooling terms/lengths. A method for using this system to manufacture a product made from a thermoplastic material is also provided.

US patent application 2016/0059461 discloses an injection molding process at substantially constant pressure with the use of rapid heating techniques, such as induction heating, at strategic locations within a mold to heat molding surfaces in a manner that mitigates problems typically associated with flow filling challenges.

US patent application 2016/0185021 discloses an injection molding apparatus and an method for the manufacture of moldable articles having an injection manifold, a plurality of hot runner nozzles, a first nozzle heater, a plurality of mold cavities positioned to receive molten material from the plurality of the hot runner nozzles, each mold cavity having at least one mold gate orifice and a mold cavity heater surrounding each mold cavity at least partially and a thermocouple associated with the mold cavity to measure directly or indirectly a temperature generated by the mold cavity heater.

US patent 5,055,025 discloses an injection mold apparatus that has an injection mold which includes two mold halves incorporating thin-walled members to define a cavity therebetween. Before injecting plastic material into the cavity, the mold is heated to a temperature above the melting point of the plastic material by circulating a heat carrier flowing through a heating device. During injection of plastic material, the flow of heat carrier is stopped for maintaining the temperature of the mold and for supporting the thin- walled members. After completely filling the cavity, the mold is cooled down to a temperature below the freezing point of the plastic material by suitably circulating the heat carrier which now passes through a cooling device. The circulation of the heat carrier is carried via two separate circulation systems, with one being close to the inner core of the mold and the other one being arranged in proximity of the sprue so that the cooling can be controlled by starting in an area distant to the sprue and progressing toward the sprue in a time- controlled manner.

US patent 5,261,806 discloses a master frame supports interchangeable mold inserts, each of which is provided with its own electrical heater and associated wiring. A recess is provided in the master frame to allow for lateral movement of the wiring, heater and mold inserts as a unit during installation and replacement. A closure member in the form of a thermocouple retainer is provided to support a temperature-controlling thermocouple inwardly of a hole within each mold insert as well as to close the recess during a molding operation.

US patent 6,168,740 discloses a plastic article that is formed in an injection mold by injecting molten plastic into the injection mold at an elevated temperature, cooling the plastic from the molten condition to a solid condition, and crystallizing a portion of the plastic by slowing down the cooling of said portion.

US patent 6,497,569 discloses a plastic article having a crystallized portion and an amorphous portion is formed. The article is produced by injecting molten plastic into a mold cavity (22) of preform mold (10). The hot plastic within the mold cavity is quickly cooled in regions which are to be amorphous and more slowly cooled or heated in regions to be crystalline. The injection mold and include cooling channels (12, 16, 24) for cooling the molten plastic and thermal insulating sleeve (46, 48) to insulate the region to be crystallized from the coolant. In another embodiment, heating elements can be located on the preform mold (10) adjacent regions of the article to be crystallized.

US patent 7,293,981 discloses a method and apparatus for compressing melt and/or compensating for melt shrinkage in an injection mold are provided. The apparatus includes a cavity mold portion adjacent a cavity plate, a core mold portion adjacent a core plate, a mold cavity formed between the mold portions, and at least one piezoceramic actuator disposed between either or both of the core plate and the core mold portion and the cavity plate and the cavity mold portion. A controller may be connected to the at least one piezoceramic actuator to activate it, thereby causing the mold cavity volume to decrease, compressing the melt. US patent 7,717,697 discloses a mold design for producing plastic, molded preforms, which may be blow-molded into a container of a final, desired shape. A preferred mold includes a temperature control system for maintaining the preform mold at a desired temperature. The temperature control system can pass fluid through channels within the preform mold to cool plastic that is injected into the preform mold. In some arrangements, a mold comprises a neck finish mold, the neck finish mold configured to transfer heat away from the molding surface toward a channel conveying a working fluid. A heat transfer member may be at least partially positioned within the channel to transfer heat to the working fluid. In some embodiments, the mold comprises a high heat transfer material.

PCT patent application WO 1988/000116 discloses a process, in which in order to avoid surface grooves running along the joint lines (15), the temperature of the otherwise cooled injection mould (11) is increased by means of a heating device (19) in a spatially limited strip-like region following the joint line (15), except in the surface region of said joint line and for a period of time which starts at the opening of the mould (11) and ends when it is completely full. This way the formation of grooves at the joint lines can be avoided without increasing the duration of the injection cycle.

There is a number of additional patent references pertaining to various aspects of injection molding of flip top closures: JP 1988062721, JP 1990128819, JP 1998076555, JP3361099, KR 784344, etc.

SUMMARY

Developers of the present technology have developed various embodiments thereof based on their appreciation of at least one technical problem associated with the prior art approaches to molding the flip top closures 100 (such as the process described in the above-mentioned patent and patent applications). Some of these problems specifically occur when attempting to reduce the molding cycle (i.e. the time required to produce a single batch of the flip top closures 100).

In order to speed any injection molding cycle a common method is to attempt to reduce the cooling time required since it typically constitutes a major portion of the molding cycle. Without changing the design of the flip top closure 100 (i.e. reducing wall thickness) a typical strategy is to, for example, lower the mold or melt temperature, or bring the cooling lines closer to the hot spots on the flip top closure 100. These approaches to decreasing the molding cycle can be broadly categorized as reducing cooling time by either increasing the cooling intensity/effectiveness or by decreasing the molten material temperature.

The geometry of the flip top closure 100 itself poses a unique problem associated with attempts to reduce the cooling time since the portion that is being filled first is typically the base 102, which is heavy. Additionally, the lid 104 is typically filled through the hinge 106, which connects the lid 104 to the base 102 (since an injection point is typically located proximate to the base 102). An injection point on the typical flip top closure 100 is shown schematically in Figure 1 at 110.

Developers of the present technology have realized that lowering the melt temperature, as means for decreasing the molding cycle, presents its special challenges when dealing with the flip top closure 100. More specifically, whereas it may be possible to fill the base 102 with the melt of lower temperature, filling the lid 104 through a narrow and/or thin hinge 106 can prove challenging or even not feasible. Additionally, the lid 104 tends to cool off quickly since it is thin, adding to the filling problem through the hinge 106 using molding material at a comparatively lower temperature.

Embodiments of the present technology attempt to mitigate at least some of the technical problems of the prior art approaches to molding the flip top closures 100. Broadly speaking, some embodiments of present technology allow a reduction in cooling time of the molded article (i.e. the flip top closure 100). In some embodiments, the reduction in the cooling time is achieved through controlling the temperature of the molding materials for filling the base 102 (via the injection point 110 located proximate to a mold portion defining the base 102) to a lower temperature (the lower temperature so selected such that to be able to fill the base 102, but is potentially too low to fill in the lid 104). Embodiments of the present technology further contemplate provisions of a heater positioned adjacent to a mold portion that defines the hinge 106. The heater is controlled to a continuous temperature that is selected such that to maintain the molding material in a state sufficient for filling the hinge 106 and the lid 104. The temperature that the molding material is maintained at (i.e. a hinge-molding temperature) can be selectable within a range that provides for filling of the hinge portion and the lid portion and the subsequent cooling thereof. Maintaining of the molding material at a desired temperature is achieved through controlling the heater to a continuous temperature (for example, by selecting a pre-determined set point thereof). In some embodiments of the present technology, the heater is controlled for continuous heating. In other embodiments, the heater can be controlled for a non-continuous heating as long as the continuous temperature of the mold insert associated with the heater is maintained. It should be noted, however, that due to environmental variables (such as heat transfer, etc.) the temperature of the molding surface associated with them mold insert can vary cycle to cycle. However, embodiments of the present technology still ensure that the molding material can flow past the mold insert associated with the heater provided in accordance with non-limiting embodiments of the present technology.

As an example, the heater can be controlled to a set point such that a temperature of an associated molding surface is maintained at a range with (i) an upper limit below a melting temperature of the molding material and (ii) a lower temperature limit above a "No-Flow Temperature" (NFT) (i.e. a temperature that is below semi-crystalline melting range). Accordingly, non-limiting set points when molding with Polypropylene are between 165°C (typical melting temperature) and 140°C (typical NFT).

Alternatively the lower temperature limit can be determined as a so-called "Vicat Softening Point" (ASTM D1525 test). The Vicat softening temperature or Vicat hardness is the determination of the softening point for materials that have no definite melting point, such as plastics. It is taken as the temperature at which the specimen is penetrated to a depth of 1 mm by a flat-ended needle with a 1 mm² circular or square cross-section. In some embodiments, a lower limit of the temperature range is above a temperature of the molding material that is injected in the base portion of the molding cavity. Accordingly, a non-limiting lower set point when molding with Polypropylene is 90°C (typical Vicat temperature). As such, the temperature of the heater is pre-selected to maintain the molding material in a flowable state as it fills the hinge 106 and the lid 104. For example, the temperature can be selected such that to control the rate of freezing of the skin layer of the molding material that has filled / is filling the hinge 106 and the lid 104. In other words, the heater power is selected such as to allow for filling the lid portion of the mold cavity with the molding material through the hinge portion by delaying solidification of the molding material in the hinge portion. This is achieved by heating the hinge defining portion of the mold, by the heater, to a hinge-molding temperature that is selectable within a level that provides for filling of the lid portion and subsequent cooling thereof.

In the specific implementation where the molding material is polypropylene and the range of temperature at which a molding surface of the hinge defining portion is from 80 degrees Celsius to 160 degrees Celsius.

In some embodiments of the present technology, the heater is implemented as: a cartridge heater, an infra-red heater, and an induction-type heater. In some embodiments of the present technology, the hinge 106 is defined by a strip mold insert and the heater can be associated with the strip mold insert. In accordance to a first broad aspect of the present technology, there is provided a method of injection molding a flip top closure having a body that includes a base and a lid connected by a hinge. The method is executable in an injection molding machine controlled by a machine controller, the injection molding machine including a mold defining a mold cavity for producing the flip top closure, the mold cavity having a base defining portion for defining the base, a lid defining portion for defining the lid, and a hinge defining portion for defining the hinge. The method is executable by the controller and comprises: causing a molding material to be heated to an injection temperature; causing injecting the molding material into the mold cavity via an injection point; causing heating of at least a portion of the hinge defining portion of the mold cavity to a continuous temperature, by a heater located adjacent the hinge defining portion of the mold cavity, during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity.

In some implementations of the method, the heating allows for filling the lid defining portion of the mold cavity with the molding material through the hinge defining portion by delaying solidification of the molding material in the hinge defining portion. In some implementations of the method, the hinge defining portion is heated by the heater to a hinge-molding temperature that is selectable within a range that provides for filling of the lid portion and subsequent cooling thereof.

In some implementations of the method, an upper limit of the range is below a melting temperature of the molding material. In some implementations of the method, a lower limit of the temperature range is above a temperature of the base defining portion of the molding cavity.

In some implementations of the method, the heating is executed across an entire cross-section of the hinge defining portion.

In some implementations of the method, the heating is executed across a portion of a cross-section of the hinge defining portion. In some implementations of the method, the heating is executed across at least a portion of a cross- section of the hinge defining portion and a portion of the lid defining portion.

In some implementations of the method, the method further comprises causing auxiliary heating of a surface of the flip top closure, the auxiliary heating being implemented via an auxiliary heater placed in the mold. In some implementations of the method, the causing auxiliary heating comprises causing an intermittent auxiliary heating.

In some implementations of the method, the method further comprises causing mold heating and cooling, the mold heating and cooling being executed by a standard heating and cooling infrastructure of the mold. In some implementations of the method, the causing heating comprises causing continuous heating by the heater.

In some implementations of the method, the causing continuous heating by the heater comprises controlling the heater to a pre-defined set-point.

In accordance with another broad aspect of the present technology, there is provided an injection molding apparatus for producing a flip top closure having a body that includes a base and a lid connected by a hinge. The injection molding apparatus comprises: an injection unit, the injection unit configured to heat a molding material to an injection temperature; a mold fluidly coupled to the injection unit, the mold defining a mold cavity for producing the flip top closure, the mold cavity having: a base defining portion for defining the base, a lid defining portion for defining the lid, and a hinge defining portion for defining the hinge; the injection unit being configured to inject the molding material into the mold cavity via an injection point; a heater placed adjacent to the hinge defining portion, the heater configured for heating of at least a part of the hinge defining portion to a continuous temperature during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity.

In some implementations of the apparatus, the hinge defining portion comprises a strap mold insert and wherein the heater is associated with the strap mold insert. In some implementations of the apparatus, the heater is a cartridge heater and wherein the cartridge heater is incorporated into the strap mold insert.

In some implementations of the apparatus, the heater is one of: a cartridge heater, an infra-red heater, a nozzle-type heater and an induction-type heater.

In some implementations of the apparatus, the mold further comprising a standard heating and cooling infrastructure for maintaining the molding material flowing through the mold cavity at an appropriate operational temperature during various portions of a molding cycle of the mold.

In some implementations of the apparatus, the mold further comprises at least one auxiliary heater located proximate to a surface of the flip top closure, when being molded, the at least one auxiliary heater configured for auxiliary heating of the surface of the flip top closure. In some implementations of the apparatus, the at least one auxiliary heater is configured for intermittent auxiliary heating of the surface of the flip top closure.

In some implementations of the apparatus, the heater being configured for heating across an entire cross-section of the hinge portion.

In some implementations of the apparatus, the heater being configured for heating across a portion of a cross-section of the hinge portion.

In some implementations of the apparatus, the heater being configured for heating across at least portion of a cross-section of the hinge portion and at least a portion of the lid defining portion. In some implementations of the apparatus, the hinge defining portion comprises a mold cavity insert.

In some implementations of the apparatus, the mold cavity insert comprises a cavity insert base and a first strap mold insert and a second strap mold insert extending from the cavity insert base. In some implementations of the apparatus, the heater is associated with at least one of the first strap mold and the second strap mold insert.

In some implementations of the apparatus, the cavity insert base is positioned in a back plate pocket defined in the mold and the first strap mold insert and a second strap mold insert extend through a cavity plate aperture that extends from the back plate pocket towards the molding cavity. In some implementations of the apparatus, a back end of the cavity insert base defines a back shoulder and wherein the back shoulder is configured to cooperate with a back plate seat defined in the mold and wherein a front end of the cavity insert base defines a front shoulder that cooperates with a front seat; at least one of (i) the back shoulder with its cooperating back plate seat and (ii) the frond shoulder with its cooperating front plate seat providing a degree of float for accommodation of thermal expansion of the mold cavity insert.

In some implementations of the apparatus, the front plate seat is used as a reference point for thermal expansion of at least a portion of the mold cavity insert.

In some implementations of the apparatus, the apparatus further comprises an insulator positioned between the first strap mold insert and a second strap mold insert and a front end of the cavity plate aperture.

In some implementations of the apparatus, the cavity insert further comprises a pair of protruding wings (970) and an insulator positioned between the pair of protruding wings and a front end of the cavity plate aperture.

In some implementations of the apparatus, the apparatus further comprises a biasing insert positioned between a plate retainer and the mold cavity insert for biasing the mold cavity insert towards the mold cavity. In some implementations of the apparatus, the use of the front plate seat as the reference point ensures that a thermal expansion of terminal ends of the first strap mold insert and the second strap mold insert is reduced resulting in minimal relative movement of shut-off features of the first strap mold insert and the second strap mold insert with respect to a complementary shut-off feature on the mold.

In some implementations of the apparatus, the heater is configured for continuous heating.

In accordance with another broad aspect of the present technology, there is provided a method of injection molding a flip top closure having a body that includes a base and a lid connected by a hinge. The method is executable in an injection molding machine controlled by a machine controller, the injection molding machine including a mold defining a mold cavity for producing the flip top closure, the mold cavity having a base defining portion for defining the base, a lid defining portion for defining the lid, and a hinge defining portion for defining the hinge; the method executable by the controller. The method comprises: causing a molding material to be heated to an injection temperature; causing injecting the molding material into the mold cavity via an injection point; causing heating at least a portion of the hinge defining portion of the mold cavity, with a heater located adjacent thereto, during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity to reduce heat removal therefrom relative to heat removal from at least one of the base defining portion and the lid defining portion. In some implementations of the method, the causing heating further comprises causing heating at least a portion of the hinge defining portion of the mold cavity during a no molded part phase in- between molding of the flip top closure in the mold cavity.

In some implementations of the method, the causing further comprises causing heating of at least a portion of the hinge defining portion of the mold cavity to a continuous temperature. In some implementations of the method, the causing comprises controlling the heater to one of a continuous heating and a non-continuous heating. BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where: Figure 1 depicts a perspective view of a prior art flip top closure.

Figure 2 depicts a top schematic view of an injection molding machine, the injection molding machine configured for implementation non-limiting embodiments of the present technology.

Figure 3 depicts a cross section of a non-limiting example of implementation of the mold that can be used in the injection molding machine of Figure 2. Figures 4A, 4B and 4C depict cross-sections of the mold implemented in accordance with alternative non-limiting embodiments of the present technology.

Figure 5 depicts another cross section of the mold of Figure 3, the mold being implemented in accordance with non-limiting embodiments of the present technology.

Figure 6 depicts block diagram of a method, the method executable in the injection molding machine of Figure 2, the injection molding machine being controlled by a machine controller.

Figure 7 depicts another cross section of the mold of Figure 3, the mold being implemented in accordance with another non-limiting embodiments of the present.

Figure 8 depicts a perspective view of a mold cavity insert implemented in accordance with alternative non-limiting embodiments of the present technology, as well as a flip top closure produced with the mold cavity insert.

Figure 9 depicts a cross section of a mold that incorporates the mold cavity insert of Figure 8, the cross section taken along an operational line of the mold.

Figure 10 depicts another cross section of the mold of Figure 8, the cross section taken transverse to the operational line of the mold. The drawings are not necessarily to scale and may be illustrated by phantom lines, diagrammatic representations and fragmentary views. In certain instances, details that are not necessary for an understanding of the implementations or that render other details difficult to perceive may have been omitted. DETAILED DESCRIPTION

Reference will now be made in detail to various non-limiting implementations for producing a flip- top closure. It should be understood that other non-limiting implementations, modifications and equivalents will be evident to one of ordinary skill in the art in view of the non-limiting implementations disclosed herein and that these variants should be considered to be within scope of the appended claims. Furthermore, it will be recognized by one of ordinary skill in the art that certain structural and operational details of the non-limiting implementations discussed hereafter may be modified or omitted (i.e. non-essential) altogether. In other instances, well known methods, procedures, and components have not been described in detail.

It is to be further expressly understood that the injection mold and its components are depicted merely as an illustrative implementation of the present technology. Thus, the description thereof that follows is intended to be only a description of illustrative examples of the present technology. This description is not intended to define the scope or set forth the bounds of the present technology. In some cases, what are believed to be helpful examples of modifications to the injection mold and/or its components may also be set forth below. This is done merely as an aid to understanding, and, again, not to define the scope or set forth the bounds of the present technology. These modifications are not an exhaustive list, and, as a person skilled in the art would understand, other modifications are likely possible. Further, where this has not been done (i.e. where no examples of modifications have been set forth), it should not be interpreted that no modifications are possible and/or that what is described is the sole manner of implementing that element of the present technology. As a person skilled in the art would understand, this is likely not the case. In addition it is to be understood that the injection mold and/or its components may provide in certain instances simple implementations of the present technology, and that where such is the case they have been presented in this manner as an aid to understanding. As persons skilled in the art would understand, various implementations of the present technology may be of a greater complexity. Furthermore, where specific details of the different implementations are presented with reference to discrete implementations, a person skilled in the art is expected to combine specific implementation details of one discrete implementation with specific implementation details of another discrete implementation, even though such a combination may not be expressly disclosed herein below.

Figure 2 depicts an example embodiment of an injection molding machine 200 for forming molded articles from molding material. In the example of Figure 2, the molded article is a flip top closure similar to the flip top closure 100 of Figure 1, albeit manufactured using the injection molding machine 200 and the associated method implemented in accordance with non-limiting embodiments of the present technology. In some embodiments of the present technology, the flip top closure is manufactured using molding material, for example, Popylpropelene (PP) or the like. Alternatively, the molding material can be High Density Polyethylene (HDPE). Other materials or combinations of materials are, of course possible.

Injection molding machine 200 has a stationary platen 202 and a movable platen 204. A hot runner 206 and a mold 208 are typically mounted in-between the stationary platen 202 and the movable platen 204. Mold 208 comprises a mold cavity plate 210 mounted to the hot runner 206, and a mold core plate 212 mounted to movable platen 204. Movable platen 204 is movable between a closed position, depicted in Figure 1, and an open position (not shown) in which the movable platen 204 is withdrawn away from the stationary platen 202 along axis "a-a" (hereinafter referred to as an "operational axis" of the injection molding machine 200).

With the movable platen 204 in the closed position, the mold cavity plate 210 and the mold core plate 212 abut one another and may be pressed together by a force exerted on the stationary platen 202 and the movable platen 204.

In the closed position, a plurality of mold cavities 214 are defined between the mold cavity plate 210 and the mold core plate 212. Molten molding material may be injected under pressure into mold cavities 214 and cooled to form molded parts. Two such cavities are depicted in Figure 1, but the mold 108 may have any number of cavities. As such, the number of the plurality of mold cavities 214 is not particularly limited and will depend on the particular implementation of the mold 208.

Mold cavities 214 receive molten molding material from an injection unit 216 through the hot runner 206. Injection unit 216 heats molding material to a desired temperature (i.e. a "molding temperature") sufficient to render the molding material in a flowable state. Injection unit 216 may, for example, compress solid pellets of molding material with a screw, heating the material and urging it toward the mold cavities 214. Other types of the injection unit 216 are well known to those skilled in the art.

Hot runner 206 comprises a backing plate 218 mounted to the stationary platen 202. A sprue bushing 226 is received through the backing plate 218 and coupled to a manifold 224, for example using bolts or the like. The sprue bushing 226 has an inner passage for receiving molten molding material from the injection unit 216.

A manifold plate 220 is mounted to the backing plate 218, for example, using bolts or other suitable fasteners. A manifold pocket 222 is defined between the manifold plate 220 and the backing plate 218. The manifold 224 is disposed within manifold pocket 222. The manifold 224 is attached to the backing plate 218 and the manifold plate 220 using alignment pins (not shown). The alignment pins may align the manifold 224 to the backing plate 218 but may allow the manifold 224 to float in the longitudinal direction of injection molding machine 200. Thermally-insulating spacers (not shown) may be provided between the manifold 224 and the backing plate 218 and/or the manifold plate 220. The manifold 124 has an inlet (not numbered) in fluid communication with the sprue bushing 226 to receive the molding material. The inlet branches into a plurality of conduits (not shown) that run internally within the manifold 224 from the sprue bushing 226 to each of a plurality of nozzles 228, to deliver molding material thereto. Nozzles 228 may form part of larger assemblies, which may for example include one or more heaters (not shown) or seals (not shown). Nozzles 228 are mounted to manifold 224, by conventional methods, well-known to those skilled in the art. Nozzles 228 may, for example, be mounted using preloaded spring packs and aligning features such as pins. Each nozzle 228 extends through a passage 244 in the manifold plate 220 to a corresponding mold cavity 214 to supply molding material thereto. Two nozzles 228 are depicted in Figure 1, however any number may be present depending on the specific implementation of the mold.

An interface between a given one of the nozzles 228 and the associated mold cavity 214 is typically referred to as a "gate" and is numbered in Figure 2 at 240. Within embodiments of the present technology, the "gating style" of the gate 240 can be mechanical (i.e. by use of a valve step to open or block the flow of the molten molding material through the gate 240) or thermal (i.e. by use of localized cooling to block the flow of the molten molding material through the gate 240 during appropriate portions of the molding cycle).

Each of the manifold plate 220, the mold cavity plate 210 and the mold core plate 212 have alignment bores 203 extending longitudinally therethrough. Alignment pins 201 are mounted to the backing plate 218, for example, using bolts or other suitable fasteners (not shown). Alignment pins 201 extend through alignment bores 203 to maintain relative alignment between the backing plate 218, the manifold plate 220, the mold cavity plate 210 and the mold core plate 212.

Within the embodiment depicted in Figure 2, there is also provided a machine controller 242. Within various embodiments of the present technology, the machine controller 242 can be implemented as a computing apparatus having a processor (not separately numbered). The processor may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software.

The processor can execute one or more functions to control operations of one or more of the components of the injection molding machine 200. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. In some embodiments of the present technology, the processor may be a general purpose processor, such as a central processing unit (CPU) or a processor dedicated to a specific purpose. Moreover, explicit use of the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read-only memory (ROM) for storing software, random access memory (RAM), and nonvolatile storage. Other hardware, conventional and/or custom, may also be included.

The machine controller 242 has access to a memory (not depicted) that stores computer executable instructions, which computer executable instructions, when executed, cause the processor to control operation of one or more of the components of the injection molding machine 200. Examples of such operations controlled by the machine controller 242 include (but are not limited to): (i) controlling plasticising of the molding material by the injection unit 216; (ii) controlling temperature of the heaters within the hot runner 206, including nozzle heaters (not depicted) associated with the nozzles 228; controlling temperature of manifold heaters 260 associated with the manifold 224; controlling temperature of a standard cavity plate heating and cooling infrastructure 262 associated with the mold cavity plate 210; controlling temperature of a standard core plate heating and cooling infrastructure 264 associated with the mold core plate 212; (iii) controlling molding material flow through the gate 240 (by either controlling the valve stem in the mechanically controlled gate 240 or controlling temperature in the thermally controlled gate 240), (iv) controlling mold opening / closing, controlling ejection of the molded parts, controlling post-mold handling equipment, other auxiliary equipment and the like.

It is noted that the standard cavity plate heating and cooling infrastructure 262 and the standard core plate heating and cooling infrastructure 264 are jointly define a standard mold heating and cooling infrastructure (not separately numbered) for maintaining the mold 208 at an appropriate operational temperature during the various portions of the molding cycle of the mold 208. As such, the standard mold heating and cooling infrastructure comprises one or more heaters and one or more cooling channels for affecting cooling and/or heating of the various portions of the mold 208, as appropriate, during the relevant portions of the molding cycle of the mold 208. With reference to Figure 3, there is depicted a non-limiting example of implementation of the mold 108. Depicted in Figure 3 are portions of: the mold cavity plate 210, a portion of a particular one of plurality of mold cavities 214 and an associated portion of the mold core plate 212. In accordance with the non-limiting embodiment of the present technology depicted in Figure 3, coupled to the mold cavity plate 210 is a mold cavity insert 302. The mold cavity insert 302 can be thought of as a "hinge defining portion" of the mold 108. To that extent, the mold cavity insert 302 is configured to define the hinge 106.

The mold cavity insert 302 comprises a cavity insert base 304. Extending from the cavity insert base 304 is a first strap mold insert 320 and a second strap mold insert 322. Each of the first strap mold insert 320 and the second strap mold insert 322 define their respective molding surface (only one is numbered at 340) for defining its respective portion of the hinge 106. In the embodiment depicted in Figure 3, the first strap mold insert 320 and the second strap mold insert 322 are unitary structures with the cavity insert base 304. It is, however, contemplated that the first strap mold insert 320 and the second strap mold insert 322 can be implemented as separate physical structures.

A particular technical effect attributable to the implementations of the first strap mold insert 320 and the second strap mold insert 322 as separate physical entities is ease of manufacturing, as well as allowing for comparatively easy replacement of worn out first strap mold insert 320 and/or the second strap mold insert 322 (the wear over time can be attributable, for example, to a comparatively small shutoff faces, which are not separately numbered, of the first strap mold insert 320 and the second strap mold insert 322). The cavity insert base 304 can be attached to the mold cavity plate 210 as follows. Defined in a back face (i.e. the face that is away from a molding face of the mold cavity plate 210, the molding face housing the mold cavity 214) of the mold cavity plate 210 is a back plate pocket 305. A back portion of the cavity insert base 304 is retained in the back plate pocket 305 by means of a plate retainer 306, which in turn is coupled to the mold cavity plate 210 by means of suitable fasteners, such as the bolts 308 or the like.

The mold cavity plate 210 defines a plate back seat 312, which cooperates with a back shoulder 310 of the cavity insert base 304. In the non-limiting embodiment depicted in Figure 3, the back shoulder 310 and the plate back seat 312 are spaced apart in a direction "b" depicted in Figure 3, which happens to be the same direction as the operational axis "a- a" described above. In other words, it can be said there is provided a degree of float in the direction "b" between the mold cavity insert 302 and the mold cavity plate 210 (at least in the cold state of the mold cavity insert 302 / the mold cavity plate 210).

The cavity insert base 304, the first strap mold insert 320 and the second strap mold insert 322 are housed in a cavity plate aperture 307 that extends from the back plate pocket 305 and terminates in a plate front seat 330, which cooperates with a front shoulder 332 of the cavity insert base 304. In the non-limiting embodiment depicted in Figure 3, there is also provided an insulator 334. The insulator 334 can be made of heat insulative material to prevent heat transfer between the first strap mold insert 320 and the second strap mold insert 322 and other components of the mold 208 (for example, to prevent heat dissipation from the first strap mold insert 320 and the second strap mold insert 322 to the other components of the mold 208 that are cooled during appropriate portions of the molding cycle).

In accordance with some of the embodiments of the present technology, there may be provided a biasing insert 314 (such as a spring or the like) for biasing the mold cavity insert 302 towards the mold cavity 214 (i.e. in the downward direction if viewed in the orientation of Figure 3). Within these embodiments, at least one of the plate back seat 312 and the plate front seat 330 (and the insulator 334 in those embodiments where the insulator 334 is provided) acts as a delimiter for the downward movement (as viewed in Figure 3) of the mold cavity insert 302 towards the mold cavity 214. In these embodiments, the biasing insert 314 acts as a compensator for thermal expansion (between a cold state and in the in-use hot state) to properly position the biasing insert 314 vis-a-vis the mold cavity 214.

In a specific non-limiting embodiment of the present technology, the plate front seat 330 (and in those embodiments, where provide, the insulator 334) can act as a reference point for the thermal expansion of the first strap mold insert 320 and the second strap mold insert 322. In the embodiments depicted in Figure 3, it can be said that such the reference point is located relatively closer to the molding surface 340 (or, in turn, a respective shut off face, which is not numbered) of the first strap mold insert 320 and the second strap mold insert 322 than to the cavity insert base 304. In some embodiments of the present technology, this spatial placement of the reference point minimizes a thermal expansion in terminal ends (not separately numbered) of the first strap mold insert 320 and the second strap mold insert 322, thus resulting in minimal relative movement of the shut-off feature on the first strap mold insert 320 and the second strap mold insert 322 with respect to a complementary shut off feature on the mold base resulting from the thermal expansion of the projecting portion with heating of the first strap mold insert 320 and the second strap mold insert 322 from an ambient temperature to an operating temperature.

Each of the first strap mold insert 320 and the second strap mold insert 322 is provided with a respective heater (only one is numbered at 324). Each of the first strap mold insert 320 and the second strap mold insert 322 is further provided with a respective thermocouple (only one numbered at 326). At least a portion of the first strap mold insert 320 is separated from a respective portion of the second strap mold insert 322 by a void 328. The void 328 is configured to at least partially thermally isolate the first strap mold insert 320 and the second strap mold insert 322. In some embodiments of the present technology, the thermocouple 326 is configured to measure the operating temperature of the associated one of the first strap mold insert 320 and the second strap mold insert 322. Responsive to the measurement of the operating temperature of the associated one of the first strap mold insert 320 and the second strap mold insert 322, the associated one of the first strap mold insert 320 and the second strap mold insert 322 can be controlled to a pre-set operating temperature (as will be described herein below). The heater 324 can be said to be positioned proximate (adjacent) to the portion of the mold 208 that defines the hinge 106 (i.e. the molding surface 340 of the first strap mold insert 320 and the second strap mold insert 322). The heater 324 is configured for heating of at least a portion of the hinge defining portion and, in some embodiments, at least a portion of the lid defining portion of the molded article (during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity 214). More specifically, the heater 324 is configured for mmaintaining of the molding material at a desired temperature. In some embodiments, this is achieved by controlling the heater 324 to a continuous temperature (for example, by selecting a pre-determined set point thereof). In some embodiments of the present technology, the heater is controlled for continuous heating. In other embodiments, the heater can be controlled for a non-continuous heating as long as the continuous temperature of the mold insert associated with the heater is maintained. It should be noted, however, that due to environmental variables (such as heat transfer, etc.) the temperature of the molding surface associated with the mold insert can vary cycle to cycle. However, embodiments of the present technology still ensure that the molding material can flow past the mold insert associated with the heater provided in accordance with non-limiting embodiments of the present technology.

As such, in accordance with the embodiments of the present technology, the keeping the molding material at a continuous temperature means keeping the molding insert that is located proximate to the flow path of the molding material at a continuous temperature. The temperature of the molding surface may of course vary insignificantly.

In the depicted embodiment of Figure 3, the heater 324 is implemented as a cartridge heater and to that extent the heater 324 is incorporated into the respective one of the first strap mold insert 320 and the second strap mold insert 322. In some embodiments of the present technology, the heater 324 being the cartridge heater can be implemented as a 4 (four) mm cartridge heater with power of between 50 (fifty) and 70 (seventy) Watts.

Even though in the depicted embodiment the heater 324 is implemented as a cartridge heater incorporated in the respective one of the first strap mold insert 320 and the second strap mold insert 322, this does not need to be so in every embodiment of the present technology. It is also noted that in the embodiment of Figure 3, a respective instance of the heater 324 is provided with each instance of the the first strap mold insert 320 and the second strap mold insert 322 such that heating to a continuous temperature is provided over an at least a portion of the cross section of the hinge 106 (i.e. that portion of the hinge 105 molded by the first strap mold insert 320 and the second strap mold insert 322), this does not need to be so in every embodiment of the present technology.

As such in alternative embodiment, it is contemplated that the heater 324 can be provided in association with at least some of the first strap mold insert 320 and the second strap mold insert 322 for heating at least a portion of the cross-section of the hinge 106 respectively associated therewith. It is further contemplated that the heater 324 can be implemented differently, other than the cartridge heater depicted in Figure 4.

As such and with reference to Figures 4A, 4B and 4C there are depicted cross-sections of the mold 208 implemented in accordance with alternative non-limiting embodiments of the present technology. More specifically, each one of the Figures 4A, 4B and 4C depicts an alternative implementation of the heater 324. More specifically, Figure 4A depicts an embodiment of a heater 324A (which is implemented as an infra red heater) and that is placed in a heater cavity 404 in proximity to the hinge defining portion of the mold (i.e. the the first strap mold insert 320). It is noted that in the embodiment of Figure 4A, there is no heater 324A provided in associated with the second strap mold insert 322), however in yet alternative implementation, a heater similar to the heater 324A can be provided in association with the second strap mold insert 322. It is also noted that in the embodiment of Figure 4A, the first strap mold insert 320 and the second strap mold insert 322 are implemented as structurally separate entities.

Figure 4B depicts an embodiment of a heater 324B (which is implemented as a nozzle-type heater) and that is positioned in proximity to the hinge defining portion of the mold (i.e. around the the first strap mold insert 320). It is noted that in the embodiment of Figure 4B, there is no heater 324B provided in associated with the second strap mold insert 322), however in yet alternative implementation, a heater similar to the heater 324B can be provided in association with the second strap mold insert 322. It is also noted that in the embodiment of Figure 4B, the first strap mold insert 320 and the second strap mold insert 322 are implemented as structurally separate entities.

Figure 4C depicts an embodiment of a heater 324C (which is implemented as an induction-type heater) and that is positioned in proximity to the hinge defining portion of the mold (i.e. around the the first strap mold insert 320). It is noted that in the embodiment of Figure 4C, there is no heater 324C provided in associated with the second strap mold insert 322), however in yet alternative implementation, a heater similar to the heater 324C can be provided in association with the second strap mold insert 322. It is also noted that in the embodiment of Figure 4C, the first strap mold insert 320 and the second strap mold insert 322 are implemented as structurally separate entities.

In yet further non-limiting embodiments of the present technology, the heating to a continuous temperature is provided over an entirety of the cross section of the hinge 106. Figure 7 depicts another non-limiting example of implementation of the mold 108. Depicted in Figure 7 are portions of the mold cavity plate 210, which is implemented substantially similar to that of Figure 3, other than for the specific differences described herein below.

In accordance with the non-limiting embodiment of the present technology depicted in Figure 7, a mold cavity insert 702 can be thought of as a "hinge defining portion" of the mold 108. To that extent, the mold cavity insert 702 is configured to define the hinge 106. The mold cavity insert 702 also comprises the first strap mold insert 320 and the second strap mold insert 322, which are provided with a respective heater (not numbered in Figure 7). However, in the embodiment of Figure 7, the first strap mold insert 320 and the second strap mold insert 322 are not separated from each other by the void 328 of Figure 3. As such, the heating to a continuous temperature is provided over the entirety of the cross section of the hinge 106 in an area depicted at 704. It should be however noted that the specific structure depicted in Figure 7 is not the only way to implement heating over the entirety of the cross section of the hinge 106 (the area depicted at 704).

In some embodiments of the present technology, the mold 208 may further include auxiliary heaters (not depicted) placed adjacent to the base defining portion 504 and/or hinge defining portion 502 for auxiliary heating of a surface of the flip top closure 100. This auxiliary heating can be continuous or intermittent and can be implemented to achieve, for example, a specific surface finish of the flip top closure 100.

Injection molding process overview

With reference to Figure 5, an overview of the injection molding process in accordance with embodiments of the present technology will be described. Figure 5 depicts another cross section of the mold 208, the mold being implemented in accordance with non-limiting embodiments of the present technology. For the purposes of the explanation to be presented below, it shall be assumed that the mold 208 implements the heater 324 of Figure 3.

It should be noted, however, that a typical injection molding process has a number of steps involved in molding and post-mold handling of the molded article. For brevity, only those steps pertinent to implementation of the non-limiting embodiments of the present technology will be described here. It is expected, however, that those of ordinary skill in the art will be able to modify, if necessary, other portions of the injection molding process.

Preparation of the molding material to an injection temperature

The injection unit 216 is configured to prepare the molding material to the injection temperature. In some embodiments of the injection temperature can be 200 degrees Celsius.

In other embodiments, the injection temperature can be between 170 degrees Celsius and 250 degrees Celsius.

Injecting the molding material into the mold cavity via an injection point

The injection unit 216 is further configured to inject the molding material into the mold cavity 214 via the injection point. In some embodiments of the present technology, the injection point is proximate to the base defining portion 504 of the flip top closure. As depicted in Figure 5, in one example, the molding material is injected on the right hand side (as viewed in Figure 5) and moves in a direction "C", i.e. left-bound towards the hinge defining portion 502 and the lid defining portion 506 of the mold 208. Heating to a continuous temperature of at least a part of the lid defining portion, by a heater located adjacent the hinge defining portion of the mold cavity, during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity

As should be recalled, embodiments of the present technology contemplate provision of the heaters 324 in association with some or all of the first strap mold insert 320 and the second strap mold insert 322. As such, embodiments of the present technology contemplate heating to a continuous temperature (using the heaters 324) at least a portion of the lid defining portion 506 and at least a portion the hinge defining portion 502 of the mold 208. It should be noted that the example of the heating of some or all of the first strap mold insert 320 and the second strap mold insert 322 are provided herein as an illustration only.

As the molding material moves from the base defining portion 504 into the hinge defining portion 502, the molding material enters a substantially smaller cross section of a molding material passage towards the lid defining portion 506 (in the direction C in Figure 5).

The heating executed by the heaters 324 located proximate to the hinge defining portion 502 allows delaying solidification of the molding material in the hinge defining portion 502 and, thus, ensures that the lid defining portion 506 is properly filled. A special technical effect attributable to at least some embodiments of the present technology, is the ability to lower the injection temperature to which the molding material is initially heated, while still ensuring proper filling of the hinge defining portion 502 and the lid defining portion 506. Thus, in turn, may allow reducing overall cycle time by reducing the cooling time required to cool the flip top closure in them old to a safe mold ejection temperature. In some embodiments of the present technology, this effect is achieved without the need to increase the injection pressure.

The temperature that the molding material is maintained at in the hinge defining portion 502 (i.e. a hinge-molding temperature) can be selectable within a range that provides for filling of the lid defining portion 506 and subsequent cooling thereof.

As an example, the heaters 324 can be controlled to a set point such that a temperature of an associated molding surface is maintained at a range with (i) an upper limit below a melting temperature of the molding material and (ii) a lower temperature limit above a "No-Flow Temperature" (NFT) (i.e. a temperature that is below semi-crystalline melting range).

Alternatively the lower temperature limit can be determined as a so-called "Vicat Softening Point" (ASTM D1525 test). The Vicat softening temperature or Vicat hardness is the determination of the softening point for materials that have no definite melting point, such as plastics. It is taken as the temperature at which the specimen is penetrated to a depth of 1 mm by a flat-ended needle with a 1 mm² circular or square cross-section. In some embodiments, a lower limit of the temperature range is above a temperature of the molding material that is injected in the base portion of the molding cavity. Figure 8 depicts a perspective view of a mold cavity insert 802 implemented in accordance with alternative non-limiting embodiments of the present technology. Figure 8 also depicts a perspective view of the flip top closure 100 manufactured (in the relevant portions thereof) using the mold cavity insert 802. The flip top closure 100 comprises the base 102 and the lid 104, joined therebetween by the hinge 106.

The mold cavity insert 802 is executed substantially similar to the mold cavity insert 302 other than for the specific differences discussed herein below.

Additional reference will be made to Figure 9 and Figure 10, in which Figure 9 depicts a cross section of a mold that incorporates the mold cavity insert of Figure 8 and Figure 10 depicts another cross section of the mold of Figure 8.

By contrasting the embodiments depicted in Figure 9 and Figure 3, for example, it will become apparent that the heaters 324 of the embodiment of Figure 9 are located closer to a molding surface (depicted generally at 960 in Figure 9). This is achieved by increasing the thickness of a strap mold inserts 840 of the embodiment of Figures 8, 9 and 10. With reference to Figure 10 and by contrasting the thickness of the strap mold insert 840 depicted therein with the thickness of the strap mold inserts 320, 322 depicted in Figure 5, as an example, one will appreciate that the embodiments of Figures 8, 9 and 10 provide much more "real estate" within the thickness of the strap mold inserts 840 for placement of the heaters 324. This is particularly true in the area proximate to the molding surface 960. It is worthwhile noting that as is clearly visible in Figure 10, the heating implemented in accordance with embodiments of the present technology is executed proximate to at least a portion of a hinge defining portion 502 and at least a portion of the lid defining portion 506. It is also worthwhile noting that the strap mold inserts 840 are associated with a step 1002.

The embodiment of Figures 8, 9, and 10 also includes a pair of protruding wings 970. The purpose of the protruding wings is to provide a supporting surface for an insulator 934 (similar to the insulator 334). Method of injection molding of the flip top closure

Given the architecture described above, it is possible to execute a method of injection molding the flip top closure 100 having a body that includes the base 102 and the lid 104 connected by the hinge 106. With reference to Figure 6, there is depicted a block diagram of a method 600. The method 600 is executable in the injection molding machine 200 controlled by the machine controller 242. The injection molding machine 200 comprises inter alia: the mold 208 defining a mold cavity 214 for producing the flip top closure 100. The mold cavity 214 can have a base defining portion for defining the base 102, a lid defining portion for defining the lid 104 and a hinge defining portion for defining the hinge 106.

Step 602 - causing a molding material to be heated to an injection temperature

The method 600 begins at step 602, where the machine controller 242 causes a molding material to be heated to an injection temperature. The injection unit 216 is configured to prepare the molding material by heating it to the injection temperature. In some embodiments of the injection temperature can be 200 degrees Celsius. In other embodiments, the injection temperature can be between 170 degrees Celsius and 250 degrees Celsius.

Step 604 - causing injecting the molding material into the mold cavity via an injection point

At step 604, the machine controller 242 causes injecting the molding material into the mold cavity 214 via an injection point.

In some embodiments of the present technology, the injection unit 216 is configured to inject the molding material into the mold cavity 214 (in case where the injection unit 216 is implemented as a one stage injection unit, also known as a reciprocating style injection unit) or via a shooting pot (where the injection unit 216 is implemented as a two-stage injection unit). Step 606 - causing heating to a continuous temperature of at least a part of the lid defining portion, by a heater located adjacent the hinge defining portion of the mold cavity, during at least a portion of an injection and at least a portion of subsequent cooling phases of molding of the flip top closure in the mold cavity

At step 606, the machine controller 242 causes heating to a continuous temperature of at least a part of the lid defining portion, by a heater located adjacent the hinge defining portion of the mold cavity, during at least a portion of an injection and at least a portion subsequent cooling phases of molding of the flip top closure in the mold cavity.

In an alternative implementation of step 606, the machine controller 242 causes heating at least a portion of the hinge defining portion of the mold cavity, with a heater located adjacent thereto, during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity to reduce heat removal therefrom relative to heat removal from at least one of the base defining portion and the lid defining portion. In some embodiments of the present technology, the at least a portion of the injection phase can be an entirety of the injection phase and/or at least a portion of the subsequent cooling phase can be an entirety of the subsequent cooling phase. In some of these alternative embodiments, the heating of at least the portion the hinge defining portion of the mold cavity to reduce heat removal from the at least a portion of the hinge defining portion (and, in some embodiments, at least a portion of the lid defining portion) is executed during the injection and cooling phases, as well as at least a portion of a "no molded part" phase, i.e. a molding phase when a previously-molded molded article (i.e. the flip top closure 100) is removed and the new molded article (i.e. the flip top closure 100) is not yet moldable. In some embodiments of the present technology, the heating of at least the portion the hinge defining portion of the mold cavity to reduce heat removal from the at least a portion of the hinge defining portion (and, in some embodiments, at least a portion of the lid defining portion) is executed during an entire molding cycle. In some embodiments of the present technology, the heater 324 is controlled to a continuous temperature (for example, by selecting a pre-determined set point thereof). In some embodiments of the present technology, the heater 324 is controlled for continuous heating. In other embodiments, the heater 324 can be controlled for a non-continuous heating as long as the continuous temperature of the mold insert associated with the heater is maintained. It should be noted, however, that due to environmental variables (such as heat transfer, etc.) the temperature of the molding surface associated with them mold insert can vary cycle to cycle.

Naturally, the above described embodiments are intended to be illustrative only and in no way limiting. The described embodiments are susceptible to many modifications of form, arrangement of parts, details and order of operation. The invention, rather, is intended to encompass all such modification within its scope, as defined by the claims.

It is noted that the foregoing has outlined some of the more pertinent non-limiting implementations. It will be clear to those skilled in the art that modifications to the disclosed non-limiting implementations can be effected without departing from the spirit and scope thereof. As such, the described non-limiting implementations ought to be considered to be merely illustrative of some of the more prominent features and applications. Other beneficial results can be realized by applying the non-limiting implementations in a different manner or modifying them in ways known to those familiar with the art. The mixing and/or matching of features, elements and/or functions between various non-limiting implementations are expressly contemplated herein as one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one implementation may be incorporated into another implementation as appropriate, unless expressly described otherwise, above. Although the description is made for particular arrangements and methods, the intent and concept thereof may be suitable and applicable to other arrangements and applications.

Claims

CLAIMS claimed is:

A method (600) of injection molding a flip top closure (100) having a body that includes a base (102) and a lid (104) connected by a hinge (106), the method executable in an injection molding machine (200) controlled by a machine controller (242), the injection molding machine including a mold (208) defining a mold cavity (214) for producing the flip top closure, the mold cavity having a base defining portion (504) for defining the base, a lid defining portion (506) for defining the lid, and a hinge defining portion (502) for defining the hinge; the method executable by the controller; the method comprising: causing (602) a molding material to be heated to an injection temperature; causing (604) injecting the molding material into the mold cavity via an injection point; causing (606) heating of at least a portion of the hinge defining portion of the mold cavity to a continuous temperature, by a heater (324, 324A, 324B, 324C) located adjacent the hinge defining portion of the mold cavity, during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity.

The method of claim 1, wherein said heating allows for filling the lid defining portion of the mold cavity with the molding material through the hinge defining portion by delaying solidification of the molding material in the hinge defining portion.

The method of claim 1 or 2, wherein the hinge defining portion is heated by the heater to a hinge-molding temperature that is selectable within a range that provides for filling of the lid portion and subsequent cooling thereof.

The method of claim 3, wherein an upper limit of the range is below a melting temperature of the molding material.

The method of claim 3, wherein a lower limit of the temperature range is above a no-flowing temperature. The method of any one of claims 3 to 5, wherein the molding material is polypropylene and the range is from 80 degrees Celsius to 160 degrees Celsius.

The method of any one of claims 1 to 6, wherein said heating is executed across an entire cross-section of the hinge defining portion.

The method of any one claims 1 to 6, wherein said heating is executed across a portion of a cross-section of the hinge defining portion.

The method of any one of claims 1 to 6, wherein said heating is executed across at least a portion of a cross-section of the hinge defining portion and a portion of the lid defining portion.

The method of any one of claims 1 to 9, further comprising causing auxiliary heating of a surface of the flip top closure, the auxiliary heating being implemented via an auxiliary heater placed in the mold.

The method of claim 10, wherein the causing auxiliary heating comprises causing an intermittent auxiliary heating.

The method of any one of claims 1 to 10, further comprising causing mold heating and cooling, the mold heating and cooling being executed by a standard heating and cooling infrastructure of the mold.

The method of any one of claims 1 to 12, wherein said causing heating comprises causing continuous heating by the heater.

The method of claim 13, wherein said causing continuous heating by the heater comprises controlling the heater to a pre-defined set-point.

An injection molding apparatus (200) for producing a flip top closure (100) having a body that includes a base (102) and a lid (104) connected by a hinge (106), the injection molding apparatus comprising: an injection unit (216), the injection unit configured to heat a molding material to an injection temperature; a mold (208) fluidly coupled to the injection unit, the mold defining a mold cavity (214) for producing the flip top closure, the mold cavity having: a base defining portion (504) for defining the base, a lid defining portion (506) for defining the lid, and a hinge defining portion (502) for defining the hinge; the injection unit being configured to inject the molding material into the mold cavity via an injection point; a heater (324, 324A, 324B, 324C) placed adjacent to the hinge defining portion, the heater configured for heating of at least a part of the hinge defining portion to a continuous temperature during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity.

16. The injection molding apparatus of claim 15, wherein the hinge defining portion comprises a strap mold insert (320, 322) and wherein the heater is associated with the strap mold insert.

17. The injection molding apparatus of claim 16, wherein the heater is a cartridge heater (324) and wherein the cartridge heater is incorporated into the strap mold insert.

18. The injection molding apparatus of claim 16, wherein the heater is one of: a cartridge heater, an infra-red heater (324A), a nozzle-type heater (324B) and an induction-type heater (324C).

19. The injection molding apparatus of any one of claims 15 to 18, the mold further comprising a standard heating and cooling infrastructure for maintaining the molding material flowing through the mold cavity at an appropriate operational temperature during various portions of a molding cycle of the mold.

20. The injection molding apparatus of any one of claims 15 to 19, wherein the mold further comprises at least one auxiliary heater located proximate to a surface of the flip top closure, when being molded, the at least one auxiliary heater configured for auxiliary heating of the surface of the flip top closure. The injection molding apparatus of claim 20, wherein the at least one auxiliary heater is configured for intermittent auxiliary heating of the surface of the flip top closure.

The injection molding apparatus of any one of claims 15 to 21, the heater being configured for heating across an entire cross-section of the hinge portion.

The injection molding apparatus of any one of claims 15 to 21, the heater being configured for heating across a portion of a cross-section of the hinge portion.

The injection molding apparatus of any one of claims 15 to 23, wherein the hinge defining portion comprises a mold cavity insert (302, 702).

The injection molding apparatus of claim 24, wherein the mold cavity insert comprises a cavity insert base (304) and a first strap mold insert (320) and a second strap mold insert (322) extending from the cavity insert base.

The injection molding apparatus of claim 15, the heater being configured for heating across at least portion of a cross-section of the hinge portion and at least a portion of the lid defining portion.

The injection molding apparatus of claim 25, wherein the heater is associated with at least one of the first strap mold and the second strap mold insert.

The injection molding apparatus of claim 25, wherein the cavity insert base is positioned in a back plate pocket (305) defined in the mold and the first strap mold insert and a second strap mold insert extend through a cavity plate aperture (307) that extends from the back plate pocket (305) towards the molding cavity.

The injection molding apparatus of claim 28, wherein a back end of the cavity insert base defines a back shoulder (310) and wherein the back shoulder is configured to cooperate with a plate back seat (312) defined in the mold and wherein a front end of the cavity insert base defines a front shoulder (332) that cooperates with a plate front seat (330); at least one of (i) the back shoulder with its cooperating back plate seat and (ii) the frond shoulder with its cooperating front plate seat providing a degree of float for accommodation of thermal expansion of the mold cavity insert.

30. The injection molding apparatus of claim 29, wherein the front plate seat is used as a reference point for thermal expansion of at least a portion of the mold cavity insert.

31. The injection molding apparatus of claim 28, further comprising an insulator positioned between the first strap mold insert and a second strap mold insert and a front end of the cavity plate aperture.

32. The injection molding apparatus of claim 28, the cavity insert further comprising a pair of protruding wings (970) and an insulator positioned between the pair of protruding wings and a front end of the cavity plate aperture.

33. The injection molding apparatus of claim 30, further comprising a biasing insert (314) positioned between a plate retainer (306) and the mold cavity insert for biasing the mold cavity insert towards the mold cavity in order to compensate for thermal expansion of the mold cavity insert.

34. The injection molding apparatus of claim 33, wherein the use of the front plate seat as the reference point ensures that a thermal expansion of terminal ends of the first strap mold insert and the second strap mold insert is reduced resulting in minimal relative movement of shut-off features of the first strap mold insert (320) and the second strap mold insert (322) with respect to a complementary shut-off feature on the mold.

35. The injection molding apparatus of any one of claims 15 to 34, wherein the heater is configured for continuous heating. 36. A method (600) of injection molding a flip top closure (100) having a body that includes a base (102) and a lid (104) connected by a hinge (106), the method executable in an injection molding machine (200) controlled by a machine controller (242), the injection molding machine including a mold (208) defining a mold cavity (214) for producing the flip top closure, the mold cavity having a base defining portion (504) for defining the base, a lid defining portion (506) for defining the lid, and a hinge defining portion (502) for defining the hinge; the method executable by the controller; the method comprising: causing (602) a molding material to be heated to an injection temperature; causing (604) injecting the molding material into the mold cavity via an injection point; causing (606) heating at least a portion of the hinge defining portion of the mold cavity, with a heater (324, 324A, 324B, 324C) located adjacent thereto, during at least a portion of an injection phase and at least a portion of a subsequent cooling phase of molding of the flip top closure in the mold cavity to reduce heat removal therefrom relative to heat removal from at least one of the base defining portion and the lid defining portion.

The method of claim 36, wherein said causing heating further comprises causing heating at least a portion of the hinge defining portion of the mold cavity during a no molded part phase in-between molding of the flip top closure in the mold cavity.

The method of any one of claims 36 or 37, wherein said causing further comprises causing heating of at least a portion of the hinge defining portion of the mold cavity to a continuous temperature.

The method of any one of the claims 36 to 38, wherein said causing comprises controlling the heater to one of a continuous heating and a non-continuous heating.