WO2018141053A1

WO2018141053A1 - Closure opening force adjustment

Info

Publication number: WO2018141053A1
Application number: PCT/CA2018/050071
Authority: WO
Inventors: Teng GUO
Original assignee: Husky Injection Molding System Ltd.
Priority date: 2017-02-03
Filing date: 2018-01-22
Publication date: 2018-08-09

Abstract

An injection molding system may include an injection mold used to form apart associated with a closure, such as a flip-top closure. The flip-top closure may have a body portion and a lid attached to the body portion by a living hinge for rotation between a closed position, in which a cylindrical protrusion that may be on the lid and an aperture that may be on the body portion may be frictionally engaged, and an open position. An opening force maybe applied to disengage the lid from the body portion in the closed position. The injection molding system may also include an in-mold closing mechanism to close the lid of the flip-top closure while the flip-top closure remains in the injection mold. The opening force of the flip-top closure may be defined by adjusting a setting of the injection molding system.

Description

CLOSURE OPENING FORCE ADJUSTMENT

TECHNICAL FIELD

This relates generally to adjusting, controlling and/or defining the opening force of a closure, including but not limited to adjusting, controlling and/or defining the opening force of a flip-top closure, formed by injection molding by adjusting and/or controlling one or more settings associated with the injection molding system and/or process.

BACKGROUND

Closures may be used to close an opening to a container. Closures may be formed in an injection molding system. Some closures provide a first part that releasably engages with a container that provides a second part to open and close an opening in the container. Some closures have two complementary parts that may be interconnected with each other. The two parts of the closure may move between open and closed operational configurations.

The two parts may be formed in different injection molding systems and/or at different times. Alternatively, the two parts may be formed together at the same time and/or in the same injection molding system. For example, a conventional flip-top closure may have a body portion and a lid. The lid may be attached to the body portion by a living hinge. The living hinge may be a single flexible portion molded integrally with the body portion and the lid, so that pivoting can occur between the body portion and the lid about the living hinge, between an open position and a closed position. A generally cylindrically shaped protrusion, sometimes referred to as a "spud", that is typically on the lid of the flip-top closure, may have an interface surface that frictionally engages with an interface surface of an aperture, sometimes referred to as an "orifice", typically on the body portion of the flip-top closure, in the closed position.

Conventional flip-top closures may be generally formed in an injection molding machine, forming part of an overall injection molding system. During a cycle of the injection molding machine, molten plastic, sometimes referred to as a "shot", can be injected into a molding cavity. The injected plastic can be held under pressure in the molding cavity, cooled, and ejected from the mold as a solidified closure with two or more identifiable parts. In an injection molding machine there may be two mold halves: a cavity half and a core half. Each mold half may include one or more steel plates (e.g. a cavity plate and a core plate). Mounted to each mold half may be multiple mold stacks formed of mold inserts that provide and create multiple molding cavities. The mold inserts may be configured to define the individual components of the flip-top closure, such as the body portion with a cylindrical aperture, a living hinge, and a lid with a cylindrical protrusion.

It is common to exercise the living hinge before the flip-top closure cools after the molding process, thereby providing flexibility and free movement of the living hinge. This may be accomplished by closing the lid onto the body portion while the body portion is held in a mold half.

When the lid of a pivoting flip-top closure is closed, typically with the cylindrical protrusion of the lid inserted into the aperture of the body, to open the lid and remove the cylindrical protrusion from engagement with the aperture it is necessary to rotate the lid about the living hinge. To create this pivoting movement, it is necessary to apply an opening torque defined as a minimum torque to the lid in an opening rotational direction that is sufficient to overcome the torque about the hinge acting in the opposite direction. The torque acting to resist rotational movement about the hinge to open the lid may result from at least the following: the frictional force created by the interface surfaces of the cylindrical protrusion and the aperture; the weight of the lid; and the inherent resistance of the living hinge itself. An opening force of the flip-top closure may be defined as the required minimum force, contributing to the opening torque, that is applied at an end edge portion of the lid opposite the living hinge for a particular flip-top closure, when the lid of the flip-top closure is in a closed position, to fully disengage the cylindrical protrusion from the aperture and open the lid by rotating the lid relative to the body portion about an axis defined by the living hinge. Properties of the living hinge and the frictional forces created by the surface interactions and interfacing between the outer surface of the protrusion and inner surface of the aperture when in the closed position may to a large extent control and substantially define the opening force of the flip-top closure.

In many existing flip-top closure injection molding systems, there is a large variation in opening torque, and the corresponding opening force, required to be applied to the lid to open the lid of flip- top closures formed across multiple molding cavities. In observations of the opening forces of flip- top closures produced by existing injection molding systems, there can be seen a significant variation in the magnitude of the opening forces across cavities in a multiple-molding cavity injection molding system, as well as a significant variation of opening forces in a single cavity over successive injection molding cycles. As such, it is complicated to control the variation in opening forces of flip-top closures formed within an injection molding system.

It is known that changes to the opening force of a flip-top closure can be made by entirely replacing particular mold components in an injection molding machine to adjust the dimensions of the molding cavity. For example, the dimensions of the molding cavity can be changed by removing a mold insert, re-cutting the steel of the mold insert to change the diameter of a formed cylindrical protrusion of the flip-top closure, and then re-inserting the mold insert into the molding machine.

However, improved apparatuses and methods for individually adjusting, controlling and/or defining the opening force of the flip-top closures formed in each cavity of a molding machine are desired, so that for example the opening force of a flip-top closure produced by a specific cavity can be adjusted, controlled and/or defined, and/or the variation of opening force across different molding cavities as well as across a series of injection molding cycles can be adjusted, controlled and/or defined.

More generally, closures formed by injection molding systems, there can be a large variation in the opening force required to be applied to a closure to move the closure to an open position / first operational configuration associated with the container.

SUMMARY

Techniques are disclosed for adjusting settings (e.g. mold insert configurations, temperature settings, etc.) associated with an injection molding system to adjust, define and/or control the application force required to move a first part associated with a closure (e.g. a lid) relative to a second part (e.g. a container), such that the parts move from a first operational configuration to a second operational configuration.

Techniques are also disclosed for adjusting settings (e.g. mold insert configurations, temperature settings, etc.) associated with an injection molding system to adjust, define and/or control the application force required to disengage a first part associated with a closure (e.g. a lid) from a second part (e.g. a container), when the two parts are engaged with each other.

Techniques are also disclosed for adjusting settings (e.g. mold insert configurations, temperature settings, etc.) associated with an injection molding system to adjust, define and/or control the application force required to disengage one part of a formed closure (e.g. a hd) from a second part of a formed closure (e.g. a body portion), when the two parts are engaged with each other. For pivoting flip-top closures, techniques are disclosed for adjusting settings associated with an injection molding system to adjust, define and/or control the opening torque and, for example, the corresponding opening force, of flip-top closures formed in an injection molding system. Techniques for adjusting / defining / controlling the opening torque and, for example, the corresponding opening force of flip-top closures may include: adjusting a mold cavity to adjust the geometrical size of a part of a flip-top closure that is formed in the injection molding system, such as the diameter of the outer surface of the cylindrical protrusion, the thickness of the cylindrical protrusion wall, the diameter of the inner surface of the aperture and the thickness of the aperture wall; adjusting properties of the material that form the flip-top closures, such as residual stress, relaxation and elastic modulus; adjusting a dimension of part of the geometrical form of a flip-top closure, such as by deformation of the cylindrical protrusion and / or the aperture after the flip-top closure has been initially formed by injection of the mold material into the cavity. In some embodiments, techniques for varying an application force / opening torque / an opening force may be performed while an injection molding system is in active operation in molding parts. For example, adjustments may be made to a setting of a component of an injection molding machine during production of the flip-top closures with no interchange of parts and/or no interruption in operation of the injection molding system, and the opening force for each molding cavity may be individually adjusted.

According to one aspect there is provided a method for forming a flip-top closure with an injection molding system having an injection mold with at least one molding cavity, a formed flip-top closure having a body portion and a lid attached to the body portion by a living hinge. The lid is operable for rotation between a closed position and an open position, wherein an application torque may be applied to the lid about the living hinge to alter an operational configuration of the lid in relation to the body portion. The method comprises: adjusting at least one setting of the injection molding system so that the application torque of the formed flip-top closure is defined; and molding the flip- top closure in the injection mold with the at least one setting of the injection molding system adjusted. According to another aspect there is provided a method for forming a flip-top closure with an injection molding system having an injection mold, a formed flip-top closure having a body portion and a lid attached to the body portion by a living hinge for rotation between a closed position in which a cylindrical protrusion of the lid and an aperture of the body portion are frictionally engaged and an open position, wherein an application force may be applied to disengage the lid from the body portion. The method comprises: adjusting at least one setting of the injection molding system so that the application force of the formed flip-top closure is defined at a threshold; and molding the flip-top closure in the injection mold with its setting adjusted.

According to another aspect there is provided a mold insert of an injection mold for molding a flip- top closure, a formed flip-top closure having a body portion and a lid attached to the body portion by a living hinge for rotation between a closed position in which a cylindrical protrusion of the lid and an aperture the body portion are frictionally engaged and an open position in which the protrusion is disengaged from the aperture, wherein an opening force may be applied to disengage the lid from the body portion for the formed flip-top closure. The mold insert comprises: a molding surface defining a molding cavity to form the flip-top closure, wherein at least a portion of the molding surface has an adjustable dimension so that the opening force of the formed flip-top closure is definable at a threshold.

According to another aspect, there is provided a mold insert of an injection mold for molding a flip- top closure, a formed flip-top closure having a body portion and a lid attached to the body portion by a living hinge for rotation between a closed position in which a cylindrical protrusion of the lid and an aperture of the body portion are frictionally engaged and an open position, wherein an opening force may be applied to disengage the lid from the body portion of the formed flip-top closure. The mold insert comprises: a molding surface defining a molding cavity to form the flip-top closure, wherein at least a portion of the molding surface has an adjustable temperature so that the opening force of the formed flip-top closure is definable at a threshold. According to another aspect, there is provided a method for forming a flip-top closure with an injection molding system having an injection mold and a flip-top closing mechanism, a formed flip- top closure having a body portion and a lid attached to the body portion by a living hinge for rotation between a closed position in which the lid and the body portion are frictionally engaged with each other and an open position, wherein an opening force may be applied to disengage the lid from the body portion of the formed flip-top closure. The method comprises: molding the flip-top closure in the injection mold; contacting the lid of the formed flip-top closure with the flip-top closing mechanism with at least one of at an adjustable position and at an adjustable angle to close the lid, so that the opening force of the formed flip-top closure is defined at a threshold.

According to another aspect, there is provided a method for forming a flip-top closure with an injection molding system having an injection mold, a formed flip-top closure having a body portion and a lid attached to the body portion by a living hinge for rotation between a closed and an open position, wherein an application torque may be applied to the lid about the living hinge to pivot the lid of the formed flip-top closure from a closed position to an open position. The method comprises: adjusting at least one setting of the injection molding system so that the application torque of the formed flip-top closure is adjusted; and molding the flip-top closure in the injection mold with the setting of the injection molding system adjusted.

According to another aspect, there is provided an injection molding system for forming a flip-top closure, said injection molding system having an injection mold with at least one molding cavity, and wherein a formed flip-top closure formed in said at least one molding cavity has a body portion and a lid attached to the body portion by a living hinge said lid being operable for rotation between a closed position and an open position, wherein an application torque may be applied to the lid about the living hinge to alter an operational configuration of the lid in relation to the body portion. The injection molding system comprises: at least one adjustable setting of the injection molding system operable to be adjustable so that the application torque of the formed flip-top closure is defined. According to another aspect there is provided a method for forming a first part associated with a closure. The method is performed using an injection molding system having an injection mold with at least one molding cavity. In use, the first part is operable to be movable relative to a second part associated with said closure upon application of an application force between a first operational configuration and a second operational configuration. The method comprises: adjusting at least one setting of the injection molding system so that the application force is defined; and molding the first part in the injection mold with the at least one setting of the injection molding system adjusted.

According to another aspect, there is provided a method for forming a closure with an injection molding system having an injection mold with at least one molding cavity, a formed closure having a first part and a second part, and said formed closure being movable upon application of an application force at a position on said first part, between a closed position in which the first part is engaged with said second part and an open position in which the first part is disengaged from said second part, wherein, the method comprises: adjusting at least one setting of the injection molding system so that the application force of the formed closure is defined; and molding the closure in the injection mold with the at least one setting of the injection molding system adjusted. According to another aspect, there is provided an injection molding system operable for forming a first part associated with a closure. The injection molding system has an injection mold with at least one molding cavity, wherein in use, said the part is operable to be movable relative to a second part upon application of an application force between a first operational configuration and a second operational configuration. The injection molding system comprises at least one adjustable setting of the injection molding system operable to be adjustable so that the application force is defined.

Conveniently, adjusting a dimension of the molding surface that defines a part such as a closure, such as a flip-top closure, may affect the geometrical size of the formed flip-top closure. This may be accomplished by making an adjustment to a component of an injection molding machine while the part remains within (and does not have to be removed from) the injection molding machine. Similarly, adjusting a temperature at or proximate a molding surface that defines the geometrical form of a portion of or the entirety of a part/closure, such as a flip-top closure, may affect the material properties of the material that forms the closure and this may be accomplished while the injection molding system is in operation.

Similarly, adjusting the position and angle at which the lid of a closure, such as a flip-top closure, is engaged by a tool during closing of the lid onto the body of each closure, while remaining in the injection mold, may affect the geometrical form of the closure and/or other characteristics of the closure that define / control the opening force.

Adjustments of one or more of these settings may allow for the ability of an operator to adjust/control/define an application force, / opening torque / opening force of each of the closures, such as flip- top closures, that is formed in an injection molding process at a particular threshold. The ability to make quick adjustment may also allow for optimization of opening torque / opening force variability across molding cavities. For example, cavities can be adjusted such that maximum overlapping of range of opening torque / opening force between molding cavities is achieved, which may reduce overall opening torque / opening force variation of the mold. The recut time and/or pilot time of an injection molding system may be reduced and the ability to adjust settings associated with an injection molding system may be utilized to compensate for manufacturing errors and/or processing variations, by providing a flexibility to change the opening force in an efficient manner.

Other features will become apparent from the drawings in conjunction with the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures which illustrate example embodiments, FIG. 1A is a perspective view of a flip-top closure in an open position, according to an embodiment;

FIG. IB is a top plan view of the flip-top closure of FIG. 1A;

FIG. 1C is a front elevation cross-sectional view of the flip-top closure of FIG. 1A;

FIG. ID is a right elevation view of the flip-top closure of FIG. 1A;

FIG. IE is a right elevation cross-sectional view of the flip-top closure of FIG. 1A; FIG. IF is an idealized partial free-body left elevation view of the flip-top closure of FIG. 1A, illustrating the forces applied for opening the lid from a closed position;

FIG. 2 is a right elevation partial cross-sectional view of a portion of an injection molding system, according to an embodiment;

FIG. 3A is a right elevation view of an aperture pin of an injection molding system, according to an embodiment;

FIG. 3B is a bottom view of the aperture pin of FIG. 3A;

FIG. 3C is a front elevation cross-sectional view of the aperture pins of FIG. 3A of the injecting molding system of FIG. 2; FIG. 3D is a right elevation cross-sectional view of an aperture pin of FIG. 3C of the injection molding system of FIG. 2;

FIG. 4A is a right elevation cross-sectional view of an aperture pin and a cylindrical protrusion pin with regional temperature control in an injection molding system, according to an embodiment;

FIG. 4B is a front elevation cross-sectional view of multiple aperture pins with regional temperature control of FIG. 4A;

FIG. 4C is a rear elevation cross-sectional view of multiple cylindrical protrusion pins with regional temperature control of FIG. 4A; FIG. 4D is a right elevation cross-sectional view of mold portions with regional temperature control in an injection molding system, according to an embodiment;

FIG. 4E is a top cross-sectional view of a mold portion taken along line I-I of FIG. 4D;

FIG. 4F is a partial cross-sectional perspective view of an aperture pin with regional temperature control, according to an embodiment; FIG. 5A is a perspective view of a lid closing tool of the injection molding system of FIG. 2;

FIG. 5B is a bottom view of the lid closing tool of FIG. 5A;

FIG. 5C is a right elevation view of the lid closing tool of FIG. 5A;

FIG. 6 is a right elevation view of the lid closing tool of FIG. 5A;

FIG. 7A is a right elevation view of an injection molding system having a lid closing device and a flip-top closure molded using the injection molding system illustrating steps for closing a lid of the flip-top closures using the lid closing device;

FIGS. 7B and 7C are top plan views illustrating the movement of a lid closing tool of a lid closing device to close a lid onto a body of a flip-top closure;

FIGS. 8, 9, 10, 11, 13A, 13B, 14 and 15 are perspective and right elevation views of a portion of an injection molding system having a lid closing device and of flip-top closures molded using the injection molding system illustrating steps for closing the lids of the flip-top closures using the lid closing device;

FIG. 16(a) is a perspective view of a closure in an open position, according to another embodiment; FIG. 16(b) is a perspective view of the closure of FIG. 16(a) in an closed position; and

FIG. 17 is a perspective view of a container and closure combination in an open position, according to another embodiment.

DETAILED DESCRIPTION

With reference initially to FIG. 1A an illustrative example closure is illustrated, in particular a flip- top closure 10 is shown in a lid open position. Flip-top closure 10 may have a body portion 12 with a top wall 20 and a side wall 18. Flip top closure 10 may also have a lid 14 and a living hinge 16 attaching lid 14 to side wall 18 of body portion 12. Flip-top closure 10 may be formed by an injection molding process, such as for example, the process described generally hereinafter. In an injection molding process, a molding material is injected in one or more molding cavities to form flip-top closures 10. The molding material may be wide variety of materials including a polymer, such as a thermoplastic or a thermosetting polymer. The molding material could be a different type of polymer such as an elastomer, or any other material suitable for injection molding and suitable for a particular flip-top closure 10. In an exemplary implementation, the molding material used for producing the flip-top closure 10 is polypropylene (PP). As can be seen in FIGS. 1A to IE, body portion 12 has a continuous side wall 18 and an integrally connected top wall 20. Side wall 18 may have a generally oval shaped cross-section, but other shapes are contemplated. Side wall 18 may define a recess portion 22. Top wall 20 may define a recess portion 24, an aperture 26 and a lip 28 surrounding aperture 26. Aperture 26 may have a generally cylindrical inner surface 26a with an inner diameter DA. Recess 22 and recess 24 may be contiguous. In some embodiments, recess 24 could be omitted and/or lip 28 could be omitted. Aperture 26 allows the content of a container (not shown) to which a flip-top closure 10 can be affixed, to be removed/dispensed from the container. The inside surface area of side wall 18 (not shown) defines features complementary to features of the corresponding surface of the container to which the flip-top closure 10 can be affixed permitting the attachment of flip-top closure 10 to a container. Examples of such features include, but are not limited to, threads, ribs and clips. In some embodiments, the inner side surface of side wall 18 could be shaped and sized to provide a press- fitted connection to the container, and/or welding or bonding of the flip-top closure 10 to the container may be provided. In some embodiments, more than one type of feature could be used. For example, the inside surface of side wall 18 could be threaded or dimensioned to permit bonding to a container.

Lid 14 may be shaped to be complementary with the shape of the recess 24 of the top wall 20 and the recess 22 of side wall 18, such that when lid 14 is closed, lid 14 may be received into recesses 22 and 24. When lid 14 is closed, interface surfaces on lid 14 and body portion 12 may come into engagement with each other, such as frictional engagement. Lid 14 may have a cylindrical protrusion 30 extending from an inward surface. Cylindrical protrusion 30 has a cylindrical outer surface 30a and an outer diameter Dp, which is sized to be received in the aperture 26 when lid 14 is closed and flip-top closure 10 is in a closed position. Cylindrical protrusion 30, lip 28 and aperture 26 may be configured to prevent the content of the container to which the flip-top closure 10 is to be affixed from flowing out of the container when lid 14 is closed. In some embodiments lid 14 and body portion 12 could have any other complementary shapes permitting the closing of the aperture 26. Lid 14 may also include a tab 32. Tab 32 may be aligned with recess 22 in side wall 18 when lid 14 is closed. As a result, a user may be able to open the lid 14 more easily by pushing and/or pulling on the tab 32. In some embodiments tab 32 and/or recess 22 could be omitted.

Living hinge 16 may pivotally connect side wall 18 to lid 14. Living hinge 16 permits the pivoting of the lid 14 relative to the side wall 18 about a transverse axis defined by living hinge 16 in order to move lid 14 between and open and closed positions. It is contemplated that living hinges of different types could be used. For example, living hinge 16 could have a single or multiple parallel thinned lines.

With particular reference to FIG. IF, an idealized partial free-body left elevation view of flip-top closure 10 is provided illustrating the forces applied for opening lid 14 from a closed position. In a closed position, cylindrical protrusion 30 on lid 14 frictionally engages with aperture 26 in recess 24 of top wall 20. In the closed position, there is a frictional force from the interference between the outer surface 30a of cylindrical protrusion 30 and the inner surface 26a of aperture 26. An application force may be the minimum force that is required to be applied to a lid, possibly at a particular position on the lid, to move the lid from a closed position to an open position. An opening force of flip-top closure 10 may be defined as the minimum force required that is applied at an end edge portion of the lid opposite the living hinge 16, to create a minimum opening torque to rotate lid 14 to open lid 14 relative to body portion 12, which in flip-top closure 10 will fully disengage cylindrical protrusion 30 from aperture 26 about an axis defined by living hinge 16. The opening force of flip-top closure 10 is controlled by factors including the weight of lid 14, properties of living hinge 16, and other forces that resist the pivoting movement, and in particular in flip-top closure 10, the interference between outer surface 30a of cylindrical protrusion 30 and inner surface 26a of aperture 26 when in the closed position.

Forces that may operate when lid 14 of flip-top closure 10 is being opened from a closed position are illustrated by the arrows shown in FIG. IF. The forces are identified as "Opening Force", "Hinge Resistance Torque", "Frictional Force" and "Weight", the direction of the arrow approximates the direction of the force, and the length of the arrow approximates the relative magnitudes of the forces. The inherent, internal hinge resistance torque may, however, be negligible compared to the other forces.

As illustrated in FIG. IF, the Opening Force may be applied generally orthogonal to the horizontal surface of lid 14, and is required to overcome all of the resistance to fully disengage cylindrical protrusion 30 from aperture 26, including the Hinge Resistance Torque of living hinge 16, the Frictional Force resulting from the interference between the outer surface 30a of cylindrical protrusion 30 and the inner surface 26a of aperture 26, and Weight of lid 14.

The forces described above with reference to FIG. IF represent an idealized representation of the opening force that may be required and the other forces acting on flip-top closure 10 to open the lid 14. As would be understood by a person skilled in the art, depending on the relative configurations of components of flip-top closure 10, the actual forces that operate in any particular real world situation may differ to some extent from those shown in FIG. IF. For example, extending the length of cylindrical protrusion 30 further into aperture 26 than shown could result in distortions to various components and additional forces in various directions acting around living hinge 16, and possibly require a different opening force to move lid 14 from the closed position to the open position. Also, there may be some additional frictional forces acting between the outer edge surface of lid 14 and the adjacent inner surfaces defining side portions of recess 24. In other example embodiments, body portion 12 may have a protrusion of some kind that may be receivable in some kind of aperture / opening on lid 14 and body portion 12 may also include its own aperture to allow passage of the contents of the container to which flip-top closure 10 is attached. Thus the interface surfaces that create a frictional resistance to moving the lid to an open position may largely result from the surface of an aperture on a lid and a surface of a protrusion on the body portion. In yet other embodiments, there may be alternate interface surfaces of the lid and the body portion that create a frictional or other force resistance to moving a lid from a closed position to an open position.

Some of the components of an illustrative injection molding system 100 which are operable for forming a plurality of flip-top closures 10 are shown in FIG. 2. Injection molding system 100 has settings associated therewith that are adjustable to allow for adjustment of forces associated with the operational configuration of lid 14, such as forces associated with the opening and closing of lid 14, including being able to adjust / define / control a closing torque or force and / or adjust / define / control an opening torque or opening force of particular flip-top closures 10 to be adjusted / defined / controlled at a particular threshold or magnitude or range. For example, adjustments may be selectively made to one or more molding cavities of a plurality of molding cavities on an individual basis, and with some settings, adjustments may be made during operation of injection molding system 100 without any change of parts or any interruption in system operation.

Making adjustments to define the opening torque, the opening force, or other application force required to move a lid from a closed position to an open position, of one or more closures such as flip-top closures 10 may reduce variation in the opening force / torque or other force of flip-top closures formed across multiple molding cavities within an injection molding system 100. Such adjustments may also increase the speed to market of produced flip-top closures, may potentially reduce re-cutting of mold portions to change molding cavities and reduce time spent on the development and pilot runs of pilot molds, and may be utilized to compensate for manufacturing errors and processing variations.

An adjustable injection molding system 100 may allow for flexibility in defining an opening torque or opening force of a flip-top closure 10 according to market needs at various times. Since opening force issues may be resolved by the injection molding system 100 operator through these adjustments, this may result in reduced service requests. Example adjustments to the settings of an injection molding system 100 to adjust/control/define the opening force of selected one or more flip-top closures 10 are described in further detail below, and may include adjusting the geometrical size of one or more portions of flip-top closures 10, such as the diameter of outer surface 30a of cylindrical protrusion 30, the thickness of the wall of cylindrical protrusion 30, the diameter of inner surface 26a of aperture 26 and the thickness of the wall of aperture 26; adjusting properties of the material that forms a flip-top closure 10, such as residual stress, relaxation and elastic modulus; adjusting a dimension of the geometrical form of a flip-top closure 10, such as by deformation of cylindrical protrusion 30 and aperture 26. Accordingly, methods may be provided for forming first and second closures, such as flip-top closures 10, with injection molding system 100 having an injection mold with a plurality of molding cavities. Each of the plurality of molding cavities may be operable for producing the first and second closures. The method may comprise: (a) adjusting a setting of injection molding system 100 so that the application torque of the first closure associated with a first selected mold is defined; (b) molding the first closure in the selected first mold cavity with the setting of injection molding system 100 associated with the selected first mold cavity adjusted; (c) adjusting a setting of injection molding system 100 so that the application torque of the second closure associated with a second selected mold cavity of said plurality of molding cavities is defined; and (d) molding the second closure in the selected second mold cavity with the setting of injection molding system 100 associated with the selected second mold cavity adjusted.

Of course, in embodiments, it may be possible to adjust settings of one or more injection molding systems associated with each of the molding cavities for forming two parts associated with a container and a closure, in which in use, a first part is engaged with a second part, and an application force is required to move the first and second parts relative to each other between open and closed operational configurations.

With reference now to FIGS. 16(a) and (b), another illustrative example closure 410 is illustrated. Closure 410 is representative of a known type of "push-pull" closure that may be attached to a container (not shown). This type of closure may be commonly used for example, with dishwashing liquid containers or with activity / sports type containers for holding activity/sports drinks. In containers that have push-pull type closures, the container can be selectively, and easily, opened and closed with simple pull and push axial movements of one closure part relative to another closure part such that the movable part may function like a valve.

In FIG. 16(a), closure 410 is shown in an open position / operational configuration; in FIG. 16(b) closure 410 is shown in a closed position / operational configuration. Closure 410 may have a body portion 412 with a lower, generally cylindrical side wall section 418 and a generally cylindrical upper outlet section 411. Closure 410 may also have an axially generally cylindrical, upper movable portion 414.

Outlet section 411 of body portion 412 may have a lower outward facing cylindrical surface 411a and an integrally connected upper cylindrical surface that may be narrower in diameter than lower surface 411a. Body portion 412 may be adapted for mounting to a container (not shown) at a lower end of body portion 412. Body portion 412 may also have an interior passageway that has an inlet 415 that in use, is in communication with the interior cavity of an attached container (where for example a fluid may be held). The passageway may extend from the inlet 415 to an upper outlet 417 that is positioned between the upper end portion of movable portion 414 and the narrower, upper surface of outlet section 411 of body portion 412. The interior passageway may have a path that provides for it to be selectively blocked and unblocked at one or more locations by axial movement of movable portion 414 relative to outlet section 411 of body portion 412 between open and closed positions. Body portion 412 may be integrally formed as a single part in an injection molding system from a known molding material. Similarly, upper movable portion 414 may be formed in an injection molding system, which may be different than the injection molding system that forms body portion 412. Movable portion 414 may be mounted onto body portion 412 at a suitable time in a known manner. With movable portion 414 mounted on outlet section 411 of body portion 412, there may be one or more sets of frictional interfacing surfaces that are provided between the movable portion 414 and body portion 412. For example, the upper movable portion 414 may have an interior, inward facing, cylindrical surface 414a that is positioned to interface and frictionally engage with the outward facing cylindrical surface 411a of outlet portion 411. The relative diameter of outward facing surface 411a and the diameter of inward facing surface 414a will at least in part, determine how "tight the fit" is between the interfacing surfaces and thus how much frictional force is generated between these interfacing surfaces. Additionally, the thickness of the cylindrical walls of outlet portion 411 and movable portion 414 may also in part determine the level of frictional force generated between the respective interfacing surfaces. The level of frictional force that is generated may determine, at least in part, the application force that is required to move the movable portion 414 from a closed position to an open position, to open the passageway within closure 410.

With reference now to FIGS. 17, another illustrative example closure and container combination 500 is illustrated. Combination 500 may include a first part - a container 505 and a second part - a closure lid 510. Container 505 may have an opening 506 that can be selectively, and easily, opened and closed with movements of one closure 510 relative to container 505. Container 505 and closure 510 may each be made of suitable plastic materials using injection molding systems and be adapted to hold various products/items.

Closure 510 may include a generally cylindrical outer side wall 516. Spaced radially inward from side wall 516 may be a sealing ring 517. Between an inward facing cylindrical surface 516a of side wall 516 and an outward facing cylindrical surface 517a of sealing ring 517 may be an annular gap 518.

Container 505 may have a generally cylindrical or truncated conical side wall 512. At an upper edge of said wall 512 may be formed an annular rib 511 that has an inner surface portion 511b and outer surface portion 511a. Rib 511 may be configured such that outer surface 511a frictionally engages with the inward facing surface 516a of side wall 516 and the inner surface portion 511b of rib 511 frictionally engages with the outward facing cylindrical surface 517a of sealing ring 517, as rib 511 is received within gap 518 to close opening 506 of container 505.

The relative diameters of outer surface 511a of rib 511 and the inward facing surface 516a of side wall 516 and the relative diameters of the inner surface portion 511b of rib 511 the outward facing cylindrical surface 517a of sealing ring 517, will at least in part, determine how "tight the fit" is between the interfacing surfaces and thus how much frictional force is generated between these interfacing surfaces. Additionally, the thickness of the cylindrical wall 516 and the thickness of ring 517 may also in part determine the level of frictional force generated between the respective interfacing surfaces. The level of frictional force that is generated may determine, at least in part, the application force that is required to be applied at a particular location or locations to remove the closure 510 from a closed position where the closure is engaged with the container, to an open position where the closure is disengaged from the container.

With reference now again to FIG. 2, injection molding system 100 may be configured and operable for producing four closures, such as flip-top closures 10 per injection cycle. It is contemplated that an injection molding system 100 could be provided for producing more or less than four closures, such as flip-top closures 10, per injection cycle. Injection molding system 100 is depicted in FIG. 2 in a mold configuration during a portion of the molding cycle of flip-top closure 10 following injection of molten plastic. PCT Application No. PCT/CA2016/050146 (published as PCT publication no. WO 2016/141461 on September 15, 2016), the entire contents of which are hereby incorporated herein by reference, discloses an injection molding system having an in-mold lid closing device. With reference now to FIGS. 2, 3D, 4A, 4C and FIG. 10, molding system 100 may include a first mold portion 102, a second mold portion 104 and an in-mold closing device, such as an in-mold lid closing device 106. Together, mold portion 102 mold portion 104 can provide a plurality of molding cavities that define the form of each molded flip-top closure 10. In-mold closing device 106 may be used to rotate and close lid 14 onto and into abutment with top wall 20 while flip-top closure 10 is still generally held in injection molding system 100, as will be described below.

Mold portion 102 may have a support plate (not shown) to which are mounted two side support members (not shown). A mold plate 112 may be mounted to the side support members. A mold insert 114 is received in a recess in mold plate 112. A plurality, such as four, spaced mold inserts 115 may be connected to mold insert 114. A corresponding number, such as four, core inserts 116 may extend through apertures defined in mold insert 114 and mold plate 112. Core inserts 116 may be connected to a core insert plate (not shown) disposed inside a cavity (not shown) defined between support plate, the side support members and the mold plate 112. Four stripper rings 124 may be disposed around core inserts 116 and extend through the apertures defined in mold insert 114 and mold plate 112. Stripper rings 124 may be connected to a stripper plate 126. Stripper plate 126 may defines apertures through which core inserts 116 extend. Stripper plate 126 may be disposed between core insert plate and mold plate 112. Mold portion 102 has other features and components which are considered not necessary to the understanding of the present technology and which would be known to a person skilled in the art, such as traditional cooling channels, including one or more cooling channels within the interior of core inserts 116. Therefore, for simplicity, these other features and components will not be described herein.

Core inserts 116, in combination with mold inserts 136 (see FIG. 4A), define the inside surfaces of body portions 12 of flip-tip closures 10. The mold insert 114 defines a portion of the outer surface of body portions 12. Mold inserts 115 define the outer surfaces of the lids 14 and a portion of the living hinges 16.

Further details of the components of core inserts 116, mold insert 114, and mold inserts 115 are shown in FIGS. 3C and 3D, as described below. Each mold insert 115 may be bolted to a mold insert 114, which may in turn be bolted to the mold plate 112. Mold inserts 136 may be cylindrical in shape and extend through apertures of mold insert 114. Each core insert 116 is located interior to a mold insert 136. Core inserts 116 may be able to move independently of mold inserts 136 to accomplish a first stage ejection, which disengages a flip-top closure 10 from mold insert 136 and raises flip-top closure 10 above mold plate 112. Core inserts 116 define a portion of the inside surfaces of body portions 12 and inside surfaces of aperture 26 and lip 28. Each stripper ring 124 fits between the cylindrical outside surface of core insert 116 and the aperture of mold insert 136 and is able to move relative to core insert 116 to accomplish a second stage of ejection by pushing on a bottom surface of flip-top closure 10 to remove flip-top closure 10 from core insert 116. Each stripper ring 124 defines a portion of the inside surfaces of a body portion 12.

Mold insert 114 may be implemented as a split mold insert, and can be made of two or more complementary parts, which can be actuated together and apart during the appropriate portions of the molding cycle. Actuation of the parts of mold insert 114 can be implemented by known techniques, such as using slides (not depicted) associated with suitable actuators (also not depicted), such as cams, servo motors and the like.

With particular reference again to FIG. 2, mold portion 104 may include a molding material injection system 150 (not shown in entirety) that may be connected to a support plate 140. The molding material injection system 150 may include a plurality of injection nozzles which may be hot runner nozzles 152 (see FIGS. 2 and 3D). Each hot runner nozzle 152 may extend through apertures defined in the support plate 140, a mold plate 142 and a mold insert 146 and may be configured and operable to inject the molding material through a gate into a molding cavity configured to form a flip-top closure 10. Each hot runner nozzle 152 may include a known type of gating technology such as for example thermal gating or valve-gating, as shown in FIG. 2. In alternative implementations, the injection nozzles may be another type of injection nozzle. The molding material injection system is used to inject the molding material into the molding cavities when the injection molding system 100 is closed (i.e. mold portions 102, 104 are forced together and held in engagement with each other). Mold portion 104 may have other features and components which are considered not necessary to be described for the understanding of the present technology and which would be known to a person skilled in the art. Therefore, for simplicity, these other features and components will not be described herein. However, of note, support plate 140 (FIG. 2) may have mounted thereto mold plate 142. Mold inserts 146 may be received in recesses in mold plate 142. Each mold insert 146 defines the outer side surface of side wall 18, an inner portion of the lid 14 and a portion of living hinge 16 of a flip-top closure 10.

Further detail of the components of mold insert 146 is shown in FIGS. 3C and 3D, as described below.

In some embodiments, mold inserts 146 can be implemented as split mold inserts. With particular reference to FIGS. 3A, 3B and 3D, for each molding cavity of injection molding system 100, mold insert 146 may include an adjustable pin 300 with an outer cylindrical surface 301 and in combination with mold insert 320 defines the contour and the diameter of the inner surface 26a of aperture 26 and the configuration of lip 28. Mold inserts 300 and 320 may be stationary with respect to mold insert 146. An adjustment screw 304 may be engaged with a tapered thread 306 in the body of adjustable aperture pin 300. As shown in FIG. 3B, a bottom view of the aperture pin of FIG. 3A, at the bottom of adjustment screw 304 there is a cross head that can be driven by a screwdriver. In other embodiments, the head of adjustment screw 304 may be of different types or shapes, for example a slot screw, and driven by the appropriate tool. The diameter of a lower portion 301a, of outer cylindrical surface 301 of adjustable pin 300 may be varied by turning adjustment screw 304 of mold insert 146 to thereby move the lower portion 301a of outer cylindrical surface

301 and the surrounding abutting mold insert 320 either outwards or inwards.

With particular reference to FIG. 3D, a cylindrical protrusion pin 302 mounted in mold insert 146 defines the contour and diameter of the inner cylindrical surface of protrusion 30. A cylindrical outer core insert 322 may define the contour and the diameter of the generally cylindrical outer surface of the cavity portion that defines surface 30a of cylindrical protrusion 30 and a portion of the inside surface of the cavity portion defining a portion of lid 14. Both cylindrical protrusion pin 302 and cylindrical outer core insert 322 may be stationary with regards to mold insert 146. A lid stripper ring 323 may fit between the outside surface of cylindrical outer core insert 322 and a surface of mold insert 146. Lid stripper ring 323 may define a portion of the cavity that defines a portion of the inner surface of cylindrical protrusion 30 and may be connected to an actuator (not shown). Lid stripper ring 323 can help to separate flip-top closure 10 from mold insert 146 during mold opening. During an injection molding cycle, when the mold opens, lid stripper ring 323 is actuated to move out in synchronization with the mold open stroke to stay in contact with flip-top closure 10. Mold insert 148 defines tab 32 of lid 14. As shown, surfaces of mold insert 146 define the remainder of lid 14 and body portion 12.

In a similar manner to adjustment screw 304 and tapered thread 306 of adjustable aperture pin 300, in some embodiments each cylindrical protrusion pin 302 associated with each molding cavity may have an adjustment screw engaged with a tapered thread in the body of cylindrical protrusion pin

302 and the diameter of a lower portion of cylindrical protrusion pin 302 may be varied by turning the adjustment screw to thereby move the lower portion of cylindrical protrusion pin 302 either outwards or inwards. The result may be that selectively for one or more molding cavities the diameter of the cavity surface portion that defines the interior cylindrical surface of cylindrical protrusion 30 may be expanded or reduced. This may result in the wall thickness of cylindrical protrusion 30 that is formed in the flip-top closure 10 of one of more molding cavities being varied / adjusted. By increasing the side wall thickness of the cavity that forms cylindrical protrusion 30, it may increase the stiffness of the resulting cylindrical protrusion 30 which may increase the opening force. By reducing the wall thickness of the cavity that forms the side wall of cylindrical protrusion 30, it may decrease the stiffness of the resulting cylindrical protrusion 30 which may decrease the opening force. In other embodiments, the diameter of a lower portion of cylindrical protrusion pin 302 associated with one or more selected molding cavities may be varied by turning the adjustment screw to thereby move the lower portion of cylindrical protrusion pin 302 either outwards or inwards and thereby increase or decrease the outer diameter of the cavity that forms the outer side wall surface of protrusion 30. For example, in an embodiment where there is no stripper ring 323, expanding the lower portion of pin 302 may cause not only the lower portion of the outer surface of pin 302 to expand, but also expand the diameter of the outer surface of core insert 322. Reducing the lower portion of pin 302 may cause not only the lower portion of the outer surface of pin 302 to be reduced, but also reduce the diameter of the outer surface of core insert 322. By being able to adjust and control the relative dimensions of the side walls of the cavity portions in selective specific molding cavities forming each cylindrical protrusion 30 and aperture 26 of a flip-top closure 10 it may be possible to adjust and control the amount of friction force that is developed between the interfacing outer surface 30a of cylindrical protrusion 30 and inner surface 26a of aperture 26 in specific molded articles from specific molding cavities. By way of example, by providing a "tighter" fit, the corresponding friction force that is developed may be increased, thus increasing the opening force. By providing a "looser" fit, the corresponding friction force that is developed may be decreased, thus decreasing the opening force.

In relation to the alternate embodiments of FIGS. 16(a), 16(b) and FIG. 17, adjustment / control of settings in the injection molding machines forming such closures 410 or closure / container combinations 500, the respective diameter dimensions and/or wall thicknesses that relate to the interfacing frictional surfaces may also be adjusted / controlled to control the corresponding application force needed to move the closure between open and closed configurations.

Injection molding system 100 may also or alternatively have regional temperature control associated with each molding cavity in the vicinity of part of the mold surfaces that define the cavities or portions of the molding cavity, such as the portion of the molding cavity or molding cavities where the aperture 26 and/or protrusion 30 and their respective interface surfaces are formed. For example, the surface temperature of various regions of each mold insert 146 may be independently adjustable, for example, by use of a rapid heating technique such as resistive heating (or joule heating), conduction, convection, use of heated fluids (e.g., superheated steam or oil in a manifold or jacket, also heat exchangers), radiative heating (such as through the use of infrared radiation from filaments or other emitters), radio frequency (RF) heating (or dielectric heating), electromagnetic inductive heating (also referred to herein as induction heating), use of thermoelectric effect (also called the Peltier- Seebeck effect), and use of heat pumps, heat pipes, cartridge heaters, or electrical resistance wires. Shown in FIG. 4A is a right elevation cross-sectional view of a portion of an aperture pin 300' and a cylindrical protrusion pin 302' with regional temperature control functionality for each of the molding cavities in injection molding system 100. In FIG. 4B aperture pins 300' are shown in a front elevation cross-sectional view. In FIG. 4C a portion of the cylindrical protrusion pin 302' is shown in a rear elevation cross-sectional view. Aperture pin 300' may have an electromagnet induction heating coil 310A' used for induction heating. An electronic oscillator (not shown) may pass a high frequency alternating current through electromagnet induction heating coils 310A'. Heating coil 310A' may be positioned proximate and / or extend to a location inside of the cavity portion that defines the side wall surfaces of the cavity portion defining side wall portions of aperture 26. The rapidly alternating magnetic field that is formed penetrates aperture pin 300', generating electric eddy currents inside aperture pin 300'. The electric eddy currents flowing through the resistance of aperture pin 300' heat it by Joule heating (the heat produced by electrical current passed through a conductor). Cylindrical protrusion pin 302' is heated by induction heating with coil 312A' in a similar manner. Heating coil 312A' may be positioned proximate and / or extend to a location inside of the area that defines the side wall surfaces of the cavity portion defining the cylindrical wall of protrusion 30. The electrical current passed to each of the aperture pins 300', 302' may be adjusted to adjust the specific heating associated with each specific molding cavity region of the plurality of molding cavities of a molding system. The electrical current may be supplied from any suitable source of power. In some embodiments the current level may be set manually for each heating coil 310A', 312A'. In other embodiments, the heating of each heating coil 310A', 312A' may be set, adjusted, and/or controlled by a control system that may include temperature sensors associated with each molding cavity region. The sensors may be in communication with a controller that can, in response to temperature signals received from the sensors in the vicinity of the molding cavity region, adjust the amount of electrical current to the heating coil 310A', 312A'. This results in regional temperature adjustment and/or control in association with each molding cavity region associated with the regions of the molding cavity where the cylindrical protrusions 30 and/or apertures 26 are formed. FIG. 4D is a right elevation cross- sectional view of a portion of mold portions 102, 104 with regional temperature control functionality in injection molding system 100. FIG. 4D illustrates additional heating locations in mold portions 102, 104, using the techniques described above with reference to heating coils 310A', 312A', for example, heating coils 310B', 312B' in mold insert 146 and heating coil 315' in mold insert 115 located proximate the outer surface of the cavity portion that forms the outer surface of lid 14 in the vicinity of where protrusion 30 is connected the lid 14.

FIG. 4E is a top cross-sectional view of mold portion 102 taken along line I-I of FIG. 4D. In the embodiment shown in FIGS. 4D, 4E, heating coil 310B' is partially cylindrical, and adjacent to areas of mold insert 146 defining lip 28, and heating coil 312B' is cylindrical and adjacent to areas of mold insert 146 defining inner surface of lid 14.

In some embodiments, cooling channels may be located adjacent to various parts of the molding injection system 100 such as molding cavities, cores and inserts. Coolant flows through the cooling channels and is directed through desired areas of core insert 116 and mold inserts 114, 146. The diameter of cooling channels, the flow rates, and temperature of the coolants, may be varied to affect the amount of heat removed.

Cooling channels may be located at any of the locations described above for heating coils, for example heating coils 310A', 310B', 312A', 312B'.

In one example, FIG. 4F illustrates a cross-sectional perspective view of an aperture pin 300" with regional temperature control, according to an embodiment. A cooling channel 330, through which coolant flows, extends through the body of aperture pin 300" adjacent outer cylindrical surface 301" towards lower portion 301a" and then returns.

To machine channels to accommodate heating coils, other heating methods contemplated above, or cooling channels may require use of unconventional manufacturing techniques such as three- dimensional printing, laser sintering and vacuum brazing.

In some embodiments, thermoelectric devices may be used to provide heating or cooling in the vicinity of mold inserts at any of the locations described above for heating coils or cooling channels.

In experimental work to date, there is evidence that a change in surface temperature of critical regions of a molding cavity may lead to a change in opening force of a flip-top closure. The following examples are provided to exemplify particular features. A person of ordinary skill in the art will appreciate that the scope of the present is not limited to the particular features exemplified by these examples. Using a sample injection molding system similar to injection molding system 100 disclosed herein, two thermal factors have been identified as having an impact on opening force: temperature of injected melt, and the cooling of the melt. Cooling largely depends on the surface temperature of the mold inserts that form the molding cavity.

Sample data was taken over the course of three experimental runs. Each run consists of five completed injection molding cycles, as described above. Each injection molding cycle is referred to as a "shot" in the graphs below. Following each shot, the opening force of the resulting flip-top closure was measured. Measurement of the opening force of the resulting flip-top closure followed standard opening force testing procedure, with a minimal resting time of 24 hours and a pulling speed of 33mm/min. As would be understood by a person skilled in the art, "resting time" is the time elapsed following demolding of the flip-top closure before the flip-top closure opening force is tested. A resting time of at least 24 hours may ensure minimized temperature differences in the flip- top closure, and minimized variation of stress relaxation effect between parts of the flip-top closure. An opening force measurement instrument is then engaged with the lid of the flip-top closure, and the "pulling speed" is the vertical speed of the measurement head of the measurement instrument. During an opening force test, the measurement head connects to the tip of the flip-top closure lid through a hook and the measurement head moves vertically to pull the lid open.

During each run, the temperature of the molding material injected into the molding cavity remained consistent, as well as consistent cooling time following injection of the molding material.

Graph 1 illustrates the temperature measured at an aperture 26 ("orifice") and cylindrical protrusion 30 ("spud") of a flip-top closure 10 over a period of time after demolding at the completion of an injection molding cycle. The dashed lines illustrate the temperature over time of the orifice and spud after a first shot. The solid lines illustrate the temperature over time of the orifice and spud after twenty shots, when the injection molding system has reached "steady state". As can be seen, there is a substantial temperature difference of up to 20 degrees Celsius at regions such as the orifice and spud, between the first shot and when steady state is reached. This data supports the theory that the temperature of the mold is changed across shots, since the temperature of the parts of the flip-top closure, such as orifice and spud, are changed across shots. The sample data taken at each of the cavities discussed below occurred during the "transient phase", meaning that over the course of five shots, the molding cavity was heating up before reaching a steady state.

The results of three runs taking place in a first cavity, as well as the steady state average, are shown in Graph 2, below.

Graph 3 displays the results in the first cavity of the opening force change for each of shots one through four against the fifth shot, across all three runs.

The results of three runs taking place in a second cavity, as well as the steady state average, are shown in Graph 4, below.

Graph 5 displays the results in the second cavity of the opening force change for each of shots one through four against the fifth shot, across all three runs.

The results of three runs taking place in a third cavity, as well as the steady state average, are shown in Graph 6, below.

Graph 7 displays the results in the third cavity of the opening force change for each of shots one through four against the fifth shot, across all three runs.

The results of three runs taking place in a fourth cavity, as well as the steady state average, are shown in Graph 8, below.

Graph 9 displays the results in the fourth cavity of the opening force change for each of shots one through four against the fifth shot, across all three runs.

The above experimental data shows that if the mold surface temperature is changed, while the temperature of the molding material being injected into the molding cavity is not changed, it may be possible to achieve a change in the opening force of flip-top closures 10 produced in a cavity.

Furthermore, by recognizing the change in opening force across a number of shots before a steady state is reached, predictability may be achieved by adjusting the temperature of a cavity to replicate steady state temperature conditions at a portion of the molding cavity such as where the protrusion and/or aperture are formed, before a steady state of the injection molding system is reached through the natural progression of successive shots. The result is that adjusting the regional temperature of at least those parts of the injection mold that form the protrusion and/or aperture can substantially replicate what would be the steady state temperature conditions of the injection molding system once it has been operating for a period of time.

By providing localized heating such as for example using electromagnet induction heating coils 310A' in aperture pins 300', the temperature in the vicinity of the mold cavity portion where aperture 26 is formed may be strictly controlled. Similarly, by providing localized heating such as for example using electromagnet induction heating coils 312A' in aperture pins 302', the temperature in the vicinity of the mold cavity portion where cylindrical protrusion 30 is formed may also be strictly controlled. Thus, with the use of either or both of heating coils 31 OA', 312A', or the other heating and cooling techniques described above, the corresponding opening force in the formed flip-top closure 10 when cylindrical protrusion 30 is received in aperture 26 may be more accurately controlled and/or predicted. Further settings associated with injection molding system 100 may be controlled, defined and/or adjusted relate to the closing of each lid 14 onto a body 12. With reference to FIGS. 2 and 8, an example in-mold closing device 106 is illustrated that may be operable to pivot a formed lid 14 about living hinge 16 to interface with top wall 20 and its recess 24, such that protrusion 30 is received within aperture 26. Closing device 106 may include a vertical linear actuator 160, a horizontal linear actuator 162 and one or more (e.g. four) lid closing tools 164, with one or more lid closing tools being provided to close each of the lids 14 with each of body portions 12 of each flip- top closure 10 being formed in injection molding system 100. Vertical linear actuator 160 may be an electrical actuator which may include a support 165, a vertical servomotor 166 connected to support 165, a vertical ball screw 168 connected to support 165 and two vertical shafts 170 (one of which is visible in FIG. 8) extending through support 165. The vertical servomotor 166 may be controlled to turn vertical ball screw 168 via a belt (not shown), which in turn causes the screw of vertical ball screw 168 and the vertical shafts to move about a vertical axis 172. Vertical servomotor 166 may have one of angled fittings 174 to receive the wires connecting vertical servomotor 166 to a power source 176, as well as the other of angled fittings 174 to receive wires connecting the vertical servomotor 166 to a controller 178. Vertical linear actuator 160 is fastened to stripper plate 126 via support 165.

Horizontal linear actuator 162 may be an electrical actuator including a support 181, horizontal servomotor 182 connected to support 181, a horizontal ball screw 184 connected to support 181 and two horizontal shafts 186 extending through support 181. Servomotor 182 is controlled to turn horizontal ball screw 184 via a belt 187 (visible in FIG. 8), which in turn causes the screw of horizontal ball screw 184 and shafts 186 to move about a horizontal axis 188. Servomotor 182 has a pair of angled fittings 190. One of the angled fittings 190 receives wires connecting servomotor 182 to power source 176. The other of angled fittings 190 receives wires connecting servomotor 182 to controller 178. Horizontal linear actuator 162 is fastened to vertical ball screw 168 and vertical shafts of vertical linear actuator 160 via support 181. As a result, when vertical servomotor 166 causes vertical ball screw 168 to move about vertical axis 172, horizontal linear actuator 162 also moves about vertical axis 172. In some embodiments, the servomotors described above could be replaced by electric motors that are not provided with feedback sensors and separate sensors could be used to sense the positions of the vertical shafts 170 and the horizontal shafts 186 along their respective axes 172, 188. In some embodiments, the servomotors and ball screw can be replaced by a linear motor. In some embodiments, one of the two actuators may be removed and a cam may be introduced to realize motion in both horizontal and vertical direction with only one actuator. In some embodiments the vertical and horizontal ball screws could be replaced by other mechanisms for converting rotary motion to linear motion, such as, for example, rack and pinion assemblies. In some embodiments, vertical linear actuator 160 and horizontal linear actuator 162 could be of a type other than electrical, for example, pneumatic or hydraulic actuators. In some embodiments, vertical linear actuator 160 and horizontal linear actuator 162 could be arranged such that axis 172 is not vertical, axis 188 is not horizontal and/or axes 172, 188 are not perpendicular to each other. In some embodiments, horizontal linear actuator 162 could not be connected to the vertical linear actuator 160. In some embodiments, instead of being connected to the mold portion 102, the in-mold lid closing device 106 could be connected to the other mold portion or to another component of injection molding system 100. It should also be noted that while axis 172 is depicted in FIG. 2 as a vertical axis and axis 188 is depicted as a horizontal axis, it may in some implementations be advantageous to provide axis 172 as a horizontal axis and axis 188 as a vertical axis whereby the entire injection molding machine 100 Is actually oriented 90 degrees to the orientation as depicted in FIG. 2. This may facilitate easier ejection of formed flip-top closures 10 from the injection molding system 100 when the mold portions 102 and 104 are opened.

Lid closing tools 164 may be connected to horizontal linear actuator 162 by a tool mounting bar 194. As can be seen in FIG. 5A, each lid closing tool 164 may have a base 196 from which a wedge- shaped body 198 extends. Wedge-shaped body 198 may extend from a heel 210 of the body at its tallest end along an inclined plane to a tip 212 of the body. A rear roller 200 may be disposed in a rear aperture in body 198 and a front roller 202 may be disposed in a front aperture in body 198. Rollers 200, 202 can rotate relative to body 198. FIG. 5B is a bottom view of the lid closing tool of FIG. 5A. FIG. 5C is a right elevation view of the lid closing tool of FIG. 5A.

FIG. 6 is a right elevation view of the lid closing tool 164 of FIG. 5A having an adjustable rear roller 200 while applying a generally downward force to drive cylindrical protrusion 30 into aperture 26. As illustrated in FIG. 6, rear roller 200 may be horizontally adjustable within the rear aperture in wedge-shaped body 198 between a front position A that is closer to tip 212 of wedge- shaped body 198, and a rear position B that is closer to heel 210 of wedge-shaped body 198.

In some embodiments, one or more of rollers 200, 202 could be replaced by a shaft that is fixed to body 198.

In some embodiments of lid closing tool 164, front roller 202 is not present.

It is also contemplated that lid closing tools 164 could have a different configuration. For example, lid closing tool 164 could have two legs extending from base 196 and one or more rollers disposed between and connected to the legs. Bases 196 of lid closing tools 164 are mounted to tool mounting bar 194 by fasteners 402. By using tool mounting bar 194 and fastener 402, lid closing tools 164 can be replaced by other lid closing tools 164 or by another type of lid closing tool suitable for closing the type of flip-top closure being molded in injection molding system 100 should injection molding system 100 be used for molding flip-top closures other than flip-top closures 10.

By being connected to horizontal linear actuator 162, lid closing tools 164 are moved about horizontal axis 188 by horizontal linear actuator 162 and vertical axis 172 by vertical linear actuator 160.

A controller 178 may be operable to control the actuation of horizontal linear actuator 162 and vertical linear actuator 160 to move lid closing tools 164 along a lid closing path 404 (shown in dotted lines in FIG. 7A) to close lids 14 of flip-top closures 10 on body portions 12 of flip-top closures 10. Controller 178 may also control the actuation of horizontal linear actuator 162 and vertical linear actuator 160 to control and adjust the velocity of lid closing tools 164 along lid closing path 404 and to control and adjust the force applied by lid closing tools 164 and adjust the point of contact with the lids 14.

In operation, at the beginning of a new molding cycle (i.e. at the start of the cavity filling portion of the molding cycle), injection molding system 100 is actuated into a mold closed configuration where mold portions 102, 104 are held in abutment with each other to form the molding cavity (not separately numbered) for molding flip-top closure 10. The actuation of injection molding system 100 into the mold closed configuration is generally known in the art and will not be described herein at any length. Each molding cavity may be defined between and by mold inserts 114, 116, 115, 136, and 146 (including 300, 302, 320, 323 and 322). The diameter of the outer surface portion 301a of adjustable pin 300 may have been adjusted prior to closure of the mold halves 102 and 104, by turning adjustment screw 304 of mold insert 146, to expand or contract the diameter of the outer surface portion 301a, and therefore may affect how the molding cavity is defined, and more particularly the diameter of the inner surface 26a of aperture 26 of molded flip-top closure 10. Adjustments may be made to the dimensions of various parts of core insert 116 and mold inserts 114, 146 to define an opening force of the formed flip-top closure 10 at a threshold. For example, reducing the diameter of the molding surface defining the inner surface 26a of an aperture 26 of molded flip-top closure 10 may increase the opening force of flip-top closure 10.

In embodiments in which cylindrical protrusion pin 302 has an adjustment screw engaged with a tapered thread in the body of cylindrical protrusion pin 302, cylindrical protrusion pin 302 may be adjusted by turning the adjustment screw to expand or contract the diameter of the outer surface of a lower portion of cylindrical protrusion pin 302. Expanding the diameter of the outer surface of a lower portion of cylindrical protrusion pin 302 may, for example, reduce the thickness of the wall of cylindrical protrusion 30, resulting in a more flexible cylindrical protrusion 30, and decrease the opening force of flip-top closure 10. In some embodiments, it is contemplated that expanding the diameter of the outer surface of a lower portion of cylindrical protrusion pin 302 may expand cylindrical outer core insert 322 to increase the diameter of cylindrical outer surface 30a.

When the mold halves 102, 104 have been closed, tonnage may then be applied by known means (such as a clamp assembly) to hold mold portion 102 and mold portion 104 together to define the molding cavity. As described above, the molding cavity is formed between core insert 116 and mold inserts 114, 146. The tonnage is applied to counteract the internal pressure caused by the molding material being injected into the molding cavity through hot runner nozzle 152. In an embodiment, the molding material used for producing flip-top closure 10 is polypropylene (PP). However, the choice of material for producing flip-top closure 10 is considered to be within the purview of a person skilled in the art. The molding material is injected into each molding cavity by molding material injection system 150 to fill each molding cavity. By providing heating to one or more localized regions of selected one or more molding cavities (such as the regions where cylindrical protrusion 30 and / or aperture 26 are formed) the molding material can be kept at its melt temperature for a longer period of time at a designated location (relative to overall mold temperature) to promote further crystalline formation. Increased crystallinity reduces stresses in the polymer and increases the flexural modulus (the ratio of stress to strain in flexural deformation, or stiffness) of the region. Adjustments may be made to the heating of various regions of core insert 116 and mold inserts 114, 146 to define an opening force of the formed flip-top closure 10 at a threshold. For example, heating cylindrical protrusion pin 302' with induction heating coil 312A' may promote further crystalline formation in cylindrical protrusion 30 region of flip-top closure 10. As a result, there may be an increased flexural modulus in cylindrical protrusion 30 of flip-top closure 10, and therefore an increased opening force for flip-top closure 10.

After injection of the molding material, the process of cooling and holding commences. As each formed flip-top closure 10 cools down, it tends to shrink. A certain amount of molding material can be added to the molding cavity to ensure that the final shape of flip-top closure is maintained. This process is generally known as packing or holding in the art. In some embodiments, surface temperature of various regions of core insert 116 and mold inserts 114, 146 for one or more selected molding cavities may be also / alternately adjusted by directing coolant flow into desired areas of core insert 116 and mold inserts 115, 146 through cooling channels that include portions disposed proximate the molding surfaces associated with forming cylindrical protrusions 30 and apertures 26. The volume and speed of the coolant flow may be adjusted to affect the amount of heat removed from these areas. The faster the coolant flows, the greater volume will flow through the cooling channels and there will be less temperature rise of the coolant from its start to end point. The flow of coolant through the cooling channels may also be throttled to retain heat in particular areas for longer.

For example, cooling aperture pin 300" by flowing coolant through cooling channel 330 may decrease the rate of crystallization in aperture 26 region of flip-top closure 10. As a result, there may be a decreased flexural modulus in aperture 26 of flip-top closure 10, and therefore a decreased opening force for flip-top closure 10.

When flip-top closure 10 has been sufficiently cooled to a temperature that is substantially safe for defect-free ejection, the tonnage is disengaged through known techniques, such as disengaging the clamp (not shown) of the injection molding system 100. During the initial stage of the mold opening, mold portion 104 is moved away from mold portion 102 while mold portion 102 is stationary. As mold portion 104 is being moved, lid stripper ring 323 may be actuated to ensure that flip-top closures 10 are held on mold portion 102. The ejectors are then reset to their molding configuration. In an alternative embodiment, during the initial stage of the mold opening, it is mold portion 102 that is moved away from mold portion 104 while mold portion 104 is stationary. In another alternative embodiment, during the initial stage of the mold opening, both mold portions 102, 104 are moved away from each other.

Once injection molding system 100 has been opened, an actuator (not shown) moves core inserts 116 and flip-top closures 10 to the position shown in FIG. 8, where lids 14 are lifted off of mold insert 114 and body portions 12 are still held on core inserts 116. Lids 14 are not in contact with any surface of mold portion 102 (not illustrated for clarity).

Once injection molding system 100 is in the configuration shown in FIG. 8, in-mold closing device 106 is actuated to move lid closing tools 164 along lid closing path 404 shown in FIG. 7A and reach the lid closed position shown in FIG. 7C.

FIGS. 8, 10, 12 and 14 are perspective views of injection molding system 100 having lid closing device 164 and of flip-top closures 10 molded using injection molding system 100, illustrating steps for closing lids 14 of flip-top closures 10 using lid closing device 164. These steps may occur while flip-top closures 10 are still warm following molding. It may be desirable to minimize dwell time between opening of injection molding system 100 and movement of lid closing tools 164, to reduce cycle time of the injection molding system 100.

The movement of lid closing tools 164 will be described below with respect to the orientation of FIGS. 9, 11, 13A, 13B and 15. It should be understood that the directions and relative spatial position of the components provided would differ should the elements of the figure be oriented differently.

Horizontal linear actuator 162 is first actuated (for example, by controller 178) to move lid closing tools 164 about horizontal axis 188 toward core inserts 116. As horizontal linear actuator 162 continues to move lid closing tools 164 horizontally, controller 178 actuates vertical linear actuator 160 to move lid closing tools 164 such that the tips of wedge-shaped bodies 198 of lid closing tools 164 come into contact with the lower right portion of lids 14. Controller 178 then continues to actuate linear actuators 160, 162 to move lid closing tools 164 along a curved portion of lid closing path 404 (illustrated, for example, in FIG. 7A, and starting at the position shown in FIGS. 8 and 9), thereby pivoting lids 14 toward body portions 12 of flip-top closures 10. Once lids 14 are generally vertical (past the position shown in FIGS. 10 and 11), controller 178 actuates lines actuators 160, 162 to move lid closing tools 164 down and to the left along a curved portion of lid closing path 404 (continuing to the position shown in FIGS. 12, 13A and 13B), thereby pivoting lids 14 toward body portions 12 of flip-top closures 10 until lids 14 are closed as shown in FIGS. 14 and 15. As seen by comparing FIGS. 8 to 15, the positions at which lid closing tools 164 make contact with flip-top closures 10 vary as lid closing tools 164 move along lid closing path 404. As can also be seen by comparing FIGS. 10 and 11 with FIGS. 12, 13A and 13B, while lids 14 are being closed (FIGS. 10 and 11), lids 14 are in contact with wedge-shaped bodies 198 of lid closing tools 164. Lids 14 continue to close as lids 14 are pivoted about an axis defined by living hinge 16, and front rollers 202 of lid closing tools 164 come into contact with lids 14. As lids 14 continue to pivot, once lids 14 are at least partially closed on body portions 12 (FIGS. 12, 13A and 13B), lids 14 come into contact with rear rollers 200 of lid closing tools 164.

As shown in FIG. 6, rear rollers 200 may be horizontally adjustable within wedge-shaped bodies 198 of lid closing tools 164. Adjusting the horizontal position of rear roller 200 leads to a change in the contact point on lid 14, as can be seen in FIG. 6. Adjustments may be made to the horizontal position of rear roller 200 to define / control an opening torque and a corresponding opening force of the formed flip-top closure 10 at a threshold.

For example, an adjustment of rear roller 200 towards front position A, (see FIG. 6) closer to the tip of wedge-shaped body 198, may result in a smaller bending of lid 14 during contact of lid closing tool 164 with lid 14 and smaller deformation of cylindrical protmsion 30. A smaller deformation of cylindrical protrusion 30 may result in less reduction in outer diameter Dp of outer surface 30a of cylindrical protrusion 30 and therefore a higher opening force for flip-top closure 10. By contrast, a larger deformation of cylindrical protrusion 30 may bend cylindrical outer surface 30a inward, reducing outer diameter Dp, and hence reducing interference between cylindrical outer surface 30a and aperture 26 resulting in a lower opening force. Furthermore, larger deformation of cylindrical protrusion 30 may decrease the flexural modulus of cylindrical protrusion 30, also contributing to a lower opening force. An adjustment of rear roller 200 towards rear position B, closer to the heel of wedge-shaped body 198, may result in greater bending of lid 14 during contact of lid closing tool 164 with lid 14, greater deformation of cylindrical protrusion 30, and therefore a lower opening force for flip-top closure 10. The presence of front roller 202 may limit bending of lid 14 during contact of lid closing tool 164 with lid 14 and may avoid introduction of a defect in cylindrical protrusion 30.

Once lids 14 are closed, controller 178 actuates horizontal linear actuator 162 to move lid closing tools 164 to the right. As lid closing tools 164 move to the right, rear rollers 200 roll over the surfaces of lids 14. It is contemplated that as rear rollers 200 rolls over the surface of lids 14, the controller 178 could actuate the vertical linear actuator 160 such that rear rollers 200 apply downward forces on lids 14 to ensure that lids 14 are properly closed. The final vertical downward position of rear rollers 200 will determine how much force is applied to push cylindrical protrusions 30 into their corresponding apertures 26.

Once lid closing tools 164 have cleared flip-top closures 10, the controller 178 actuates linear actuators 160, 162 to first move lid closing tools 164 to the right and down along a curved portion of lid closing path 404 and then only to the right about axis 188 until lid closing tools 164 are returned to their initial positions (as seen in FIGS. 8 and 9).

In an embodiment, controller 178 controls actuation of linear actuators 160, 162 such that the speed of lid closing tools 164 varies along lid closing path 404. For example, lid closing tools 164 could be moved faster by linear actuators 160, 162 when lid closing tools 164 are not in contact with lids 14 then when lid closing tools 164 are in contact with lids 14.

In an embodiment, controller 178 controls actuation of linear actuators 160, 162 such that the downward force applied on the lid of lid closing tools 164 varies along lid closing path 404. For example, lid closing tools 164 could be controlled by linear actuators 160, 162 to apply more force when lid closing tools 164 are about to close lids 14 onto body portions 12 and to then apply less force once lids 14 are closed.

In another embodiment, controller 178 controls the actuation of linear actuators 160, 162 such that the forces applied by lid closing tools 164 remain constant along lid closing path 404. It is contemplated that lid closing path 404 could differ from the one illustrated in FIGS. 7A, 7B and 7C. Two factors which can determine the shape of lid closing path 404 include, but are not limited to, the geometry of flip-top closures 10 and the geometry of lid closing tools 164. Therefore, the use of vertical linear actuator 160 and horizontal linear actuator 162 to move lid closing tools 164 about axes 172, 188 to close lids 14 on body portions 12 while flip-top closures 10 are held on mold portion 102 allows the shape of lid closing path 404 to be changed, allows for the control and adjustment of the velocity (i.e. speed and direction) of lid closing tools 164 and allows for the control and adjustment of the forces applied by lid closing tools 164. Changing the geometry of lid closing tool 164 may be done by adjusting rear roller 200 within wedge-shaped body 198, allowing the shape of lid closing path 404 to be changed.

The "shoe height" of lid closing tool 164 is the starting height of the lid closing tool 164, measured from the bottom of the rear roller 200 to mold surface of mold plate 112. Because the lid closing tool 164 changes in vertical position along lid closing path 404, the height of lid closing tool 164 also changes along lid closing path 404. However, when same closing curve profile is maintained, a change of starting shoe height induces a shift of the closing path in the vertical direction, which affects initial contact position between the rear roller 200 and lid 14. The location of the initial contact between the rear roller 200 and lid 14 may determine bending of lid 14 and deformation of cylindrical protrusion 30. Sample data was also taken upon adjustment of the shoe height of a lid closing tool 164. As illustrated in Graph 10 below, results show a link between the shoe height of the lid closing tool 164 that is used to close lid 14 onto body 12 following molding of flip-top closure 10, as described above, and the opening force of the resultant flip-top closure 10.

Adjustments may be made to the starting position "shoe height" of lid closing tool 164 to define/ control / adjust the opening force of the formed flip-top closure 10, such as defining a threshold. Adjustment of the shoe height of lid closing tool 164 may adjust the position and angle at which various parts of lid closing tool 164, for example wedge-shaped body 198, front roller 202 and rear roller 200, make contact with lid 14, and may impact, for example, deformation of cylindrical protrusion 30 and affect the opening force of flip-top closure 10. Once lids 14 are closed and lid closing tools 164 have been returned to their initial positions, flip-top closures 10 are ejected from mold portion 102. To eject flip-top closures 10, stripper plate 126 is moved upwards (with respect to the orientation of FIG. 9) by an actuator (not shown) while core inserts 116 remain stationary. As a result, stripper rings 124 move upwards (with respect to the orientation of FIG. 9) relative to core inserts 116 and extends beyond core inserts 116, which pushes flip-top closures 10 off of core inserts 116.

In order to remove flip-top closures 10 from injection molding system 100, a part removal apparatus is provided to push the ejected flip-top closures 10 out of injection molding system 100. Once flip- top closures 10 have been ejected from the injection molding system 100, the injection molding system 100 is closed in order to begin another injection cycle. In alternative embodiments, a separate part removal apparatus (not depicted) can be used for removing flip-top closures 10 from injection molding system 100. Implementation of such part removal apparatus is known to those of skill in the art and, as such, will not be discussed here at any length.

It is contemplated that the injection molding system 100 could be oriented so as to separate about a plane oriented at any angle, and that depending on the angle of this plane, a mechanism for pushing flip-top closures 10 out of the injection molding system 100 may or may not be necessary.

In some embodiments, injection molding system 100 could be oriented so as to separate about a vertical plane. As would be understood, in such an implementation linear actuator 160 would be the horizontal linear actuator and linear actuator 162 would be the vertical linear actuator. In such an implementation, when injection molding system 100 separates about a vertical plane, ejected flip- top closures 10 fall out of injection molding system 100 by gravity.

While injection molding system 100 is adapted to injection mold flip-top closures, in other embodiments the features described may be applied to other types of injection molding machines and injection molds. The above described embodiments are intended to be illustrative only and in no way limiting. The described embodiments of carrying out the invention are susceptible to many modifications of form, arrangement of parts, details and order of operation. Other variations are possible.

When introducing elements of the present invention or the embodiments thereof, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

Claims

WHAT IS CLAIMED IS:

1. A method for forming a flip-top closure (10) with an injection molding system (100) having an injection mold with at least one molding cavity, a formed flip-top closure (10) having a body portion (12) and a lid (14) attached to the body portion by a living hinge (16), said lid (14) being operable for rotation between a closed position and an open position, wherein an application torque may be applied to the lid (14) about the living hinge (16) to alter an operational configuration of the lid (14) in relation to the body portion, the method comprising:

adjusting at least one setting of the injection molding system so that the application torque of the formed flip-top closure (10) is defined; and

molding the flip-top closure (10) in the injection mold with the at least one setting of the injection molding system (100) adjusted.

2. A method as claimed in claim 1 wherein one of the body portion (12) and the lid (14) has a cylindrical protrusion (30) and the other of the body portion (12) and the lid (14) has an aperture (26), the protrusion (30) being inserted in the aperture (26) and engaged therein in the closed position, and wherein after said flip-top closure (10) has been formed, said application torque may be applied to the lid (14) about the living hinge (16) to alter the operational configuration of the lid (14) in relation to the body portion (12), from a closed configuration to an open configuration.

3. The method of claims 1 or 2, further comprising:

adjusting a setting of a flip-top closing mechanism of the injection molding system (100) so that the application torque of the formed flip-top closure (10) is defined;

closing the lid (14) of the formed flip-top closure (10) with the flip-top closing mechanism while the flip-top closure (10) remains in the injection mold; and

ejecting the formed flip-top closure (10) from the injection mold.

4. The method of claims 1, 2 or 3, wherein adjusting at least one setting of the injection molding system (100) comprises adjusting a dimension of at least part of the injection mold so that the application torque of the formed flip-top closure (10) is defined.

5. A method as claimed in claim 1 wherein said method is for forming a flip-top closure (10) with an injection molding system (100) having an injection mold with a plurality of molding cavities, each of said plurality of molding cavities operable for producing a formed flip-top closure (10) having a body portion (12) and a lid (14) attached to the body portion (12) by a living hinge (16) for rotation between a closed position and an open position, wherein an application torque may be applied to the lid (14) about the living hinge (16) to alter the operational configuration of the lid (14) from the closed position to the open position, the method comprising:

adjusting at least one setting of the injection molding system (100) associated with a selected mold cavity of said plurality of mold cavities so that the application torque of the formed flip-top closure (10) associated with a selected mold cavity of said plurality of molding cavities is defined; and

molding the flip-top closure (10) in said selected mold cavity with the at least one setting of the injection molding system (100) associated with the selected mold cavity adjusted.

6. A method as claimed in claim 5 wherein said method is for forming first and second flip-top closures (10) with an injection molding system (100) having an injection mold with a plurality of molding cavities, each of said plurality of molding cavities operable for producing first and second flip-top closures (10) each having a body portion (12) and a lid (14) attached to the body portion (12) by a living hinge (16) for rotation between a closed position in which a cylindrical protrusion (30) of the lid (14) and an aperture (26) of the body portion (12) are frictionally engaged and an open position, wherein an application torque may be applied to the lid (14) about the living hinge (16) to alter an operational configuration of the lid (14) in relation to the body portion (12), the method comprising: adjusting a first setting of the injection molding system (100) so that the application torque of the first formed flip-top closure (100) associated with a first selected mold cavity of said plurality of molding cavities is defined; and

molding the first flip-top closure (100) in said selected first mold cavity with the first setting of the injection molding system (100) associated with the selected first mold cavity adjusted; adjusting a second setting of the injection molding system (100) so that the application torque of the second formed flip-top closure (100) associated with a second selected mold cavity of said plurality of molding cavities is defined; and

molding the second flip-top closure in said selected second mold cavity with the second setting of the injection molding system associated with the selected second molding cavity adjusted.

7. A method for forming a flip-top closure (10) with an injection molding system (100) having an injection mold, a formed flip-top closure (10) having a body portion (12) and a lid (14) attached to the body portion (12) by a living hinge (16) for rotation between a closed position in which a cylindrical protrusion (26) of the lid (14) and an aperture of the body portion (12) are frictionally engaged, and an open position, wherein an application force may be applied to disengage the lid (14) from the body portion (12), the method comprising: adjusting at least one setting of the injection molding system (100) so that said application force of the formed flip-top closure (10) is defined at a threshold; and

molding the flip-top closure (100) in the injection mold with its setting adjusted.

8. The method of claim 7, wherein said application force is an opening force and wherein said method further comprises:

adjusting said at least one setting of a flip-top closing mechanism of the injection molding system (100) so that the opening force of the formed flip-top closure (10) is defined at a threshold;

closing the lid (14) of the formed flip-top closure with the flip-top closing mechanism while the flip-top closure (10) remains in the injection mold; and

ejecting the formed flip-top closure (10) from the injection mold.

9. The method of claims 7 or 8, wherein said application force is an opening force and wherein said adjusting said at least one setting of the injection molding system (100) comprises adjusting a dimension of at least part of the injection mold that forms the cylindrical protmsion (30) so that the opening force of the formed flip-top closure (10) is defined at a threshold.

10. The method of any one of claims 7, 8 or 9, wherein said application force is an opening force and wherein said adjusting at least one setting of the injection molding system (100) comprises adjusting a dimension of at least part of the injection mold that forms the aperture so that the opening force of the formed flip-top closure (10) is defined at a threshold.

11. The method of any one of claims 7 to 10, wherein said application force is an opening force and wherein said adjusting at least one setting of the injection molding system comprises adjusting a temperature of at least part of the injection mold that forms at least part of the cylindrical protrusion (30) so that the opening force of the formed flip-top closure (10) is defined at a threshold.

12. The method of any one of claims 7 to 1 1 , wherein said application force is an opening force and where said adjusting at least one setting of the injection molding system (100) comprises adjusting a temperature of at least part of the injection mold that forms at least part of the aperture (26) so that the opening force of the formed flip-top closure (100) is defined at a threshold.

13. A mold insert of an injection mold for molding a flip-top closure (10), a formed flip-top closure (10) having a body portion (12) and a lid (14) attached to the body portion (12) by a living hinge (16) for rotation between a closed position in which a cylindrical protrusion (30) of the lid (14) and an aperture (26) of the body portion (12) are frictionally engaged and an open position in which the protrusion (30) is disengaged from the aperture (26), wherein an opening force may be applied to disengage the lid (14) from the body portion (12) for the formed flip-top closure (10), the mold insert comprising:

a molding surface defining a molding cavity to form the flip-top closure (10), wherein at least a portion of the molding surface has an adjustable dimension so that the opening force of the formed flip-top closure (10) is definable at a threshold.

14. The mold insert of claim 13, wherein at least a portion of the molding surface that forms the cylindrical protrusion (30) of the formed flip-top closure (10) has an adjustable dimension so that the opening force of the formed flip-top closure (10) is definable at a threshold.

15. The mold insert of claim 13, wherein at least a portion of the molding surface that forms the aperture (26) has an adjustable dimension so that the opening force of the formed flip-top closure (10) is definable at a threshold.

16. A mold insert (146) of an injection mold for molding a flip-top closure (10), a formed flip- top closure having a body portion (12) and a lid (14) attached to the body portion (12) by a living hinge (16) for rotation between a closed position in which a cylindrical protrusion (30) of the lid (14) and an aperture (26) of the body portion (12) are frictionally engaged and an open position, wherein an opening force may be applied to disengage the lid (14) from the body portion (12) of the formed flip-top closure (10), the mold insert comprising:

a molding surface defining a molding cavity to form the flip-top closure (10), wherein at least a portion of the molding surface has an adjustable temperature so that the opening force of the formed flip-top closure is definable at a threshold.

17. The mold insert of claim 16, wherein at least a portion of the molding surface that forms the cylindrical protrusion (30) has an adjustable temperature so that the opening force of the formed flip-top closure (10) is definable at a threshold.

18. The mold insert of claim 16, wherein at least a portion of the molding surface that forms the aperture (26) has an adjustable temperature so that the opening force of the formed flip-top closure (10) is definable at a threshold.

19. A method for forming a flip-top closure (10) with an injection molding system (100) having an injection mold and a flip-top closing mechanism, a formed flip-top closure (10) having a body portion (12) and a lid (14) attached to the body portion by a living hinge (16) for rotation between a closed position in which the lid (14) and the body portion (12) are frictionally engaged with each other and an open position, wherein an opening force may be applied to disengage the lid (14) from the body portion (12) of the formed flip-top closure (10), the method comprising:

molding the flip-top closure (10) in the injection mold;

contacting the lid (14) of the formed flip-top closure (10) with the flip-top closing mechanism with at least one of at an adjustable position and at an adjustable angle to close the lid (14), so that the opening force of the formed flip-top closure (10) is defined at a threshold.

20. The method of claim 19, further comprising:

adjusting the position at which the flip-top closing mechanism contacts the lid (14) of the formed flip-top closure (10) so that the opening force of the formed flip-top closure is defined at a threshold.

21. The method of claims 19 or 20, further comprising:

adjusting the angle at which the flip-top closing mechanism contacts the lid (14) of the formed flip-top closure (10) so that the opening force of the formed flip-top closure (10) is defined at a threshold.

22. The method of claim 19, further comprising:

adjusting a starting position of the flip-top closing mechanism prior to contacting the lid (14) of the formed flip-top closure (10).

23. The method of claim 22, further comprising:

adjusting a path travelled by the flip-top closing mechanism between the starting position and contacting the lid (14) of the formed flip-top closure (10).

24. The method of claim 19 further comprising adjusting a contact position of a roller (200) with the lid of the flip-top closure.

25. The method of claim 24 wherein said contact position is adjusted towards a front portion of said lid (14).

26. A method for forming a flip-top closure (10) with an injection molding system (100) having an injection mold, a formed flip-top closure (10) having a body portion (12) and a lid (14) attached to the body portion (12) by a living hinge (16) for rotation between a closed and an open position, wherein an application torque may be applied to the lid (14) about the living hinge (16) to pivot the lid (14) of the formed flip-top closure (10) from a closed position to an open position, the method comprising: adjusting at least one setting of the injection molding system (100) so that the application torque of the formed flip-top closure (10) is adjusted; and

molding the flip-top closure(lO) in the injection mold with the setting of the injection molding system adjusted.

27. A method as claimed in claim 26 wherein one of the lid (14) and the body portion (12) has a cylindrical protrusion and the other of the lid and the body has an aperture, and wherein the protrusion and the aperture are frictionally engaged when the lid (14) is in a closed position, and wherein said application torque may be applied to the lid (14) about the living hinge (16) to move the lid (14) from said closed position to said open position.

28. The method of claim 27, further comprising:

adjusting a setting of a flip-top closing mechanism of the injection molding system (100) so that the application torque of the formed flip-top closure (10) is adjusted;

ejecting the formed flip-top closure from the injection mold.

29. The method of claims 27 or 28, wherein adjusting at least one setting of the injection molding system (100) comprises adjusting a dimension of at least part of the injection mold that forms the cylindrical protrusion so that the opening force of the formed flip-top closure is adjusted.

30. The method of claim 29, wherein adjusting at least one setting of the injection molding system (100) comprises adjusting a dimension of at least part of the injection mold that forms the aperture (26) so that the opening force of the formed flip-top closure (10) is adjusted.

31. The method of any one of claims 27 to 30, wherein adjusting at least one setting of the injection molding system (100) comprises adjusting a temperature of at least part of the injection mold that forms the cylindrical protrusion (30) so that the opening force of the formed flip-top closure (10) is adjusted.

32. The method of any one of claims 27 to 31, wherein adjusting at least one setting of the injection molding system (100) comprises adjusting a temperature of at least part of the injection mold that forms the aperture (26) so that the opening force of the formed flip-top closure (10) is adjusted.

33. The method of claim 32 wherein said adjusting the temperature is performed with a heater (310A\ 310B', 312A', 312B') located proximate the at least part of the injection mold.

34. The method of any one of claims 27 to 31, wherein adjusting at least one setting of the injection molding system comprises adjusting a temperature of at least a part of the injection mold that forms the aperture (26) so that the temperature of a molding cavity can achieve substantially steady state temperature conditions at the part of the mold that forms the aperture (26).

35. The method of any one of claims 27 to 32, wherein adjusting at least one setting of the injection molding system comprises adjusting a temperature of at least a part of the injection mold that forms the protrusion (30) so that the temperature of a molding cavity can achieve substantially steady state temperature conditions at the part of the mold that forms the protrusion.

36. An injection molding system (100) for forming a flip-top closure (10) , said injection molding system (100) having an injection mold with at least one molding cavity, and wherein a formed flip-top closure (10) formed in said at least one molding cavity has a body portion (12) and a lid (14) attached to the body portion by a living hinge (16) said lid (14) being operable for rotation between a closed position and an open position, wherein an application torque may be applied to the lid (14) about the living hinge (16) to alter an operational configuration of the lid (14) in relation to the body portion (12), the injection molding system comprising:

at least one adjustable setting of the injection molding system (100) operable to be adjustable so that the application torque of the formed flip-top closure (100) is defined.

37. A system as claimed in claim 36 wherein one of the body portion (12) and the lid (14) has a cylindrical protrusion and the other of the body portion (12) and the lid (14) has an aperture, such that in operation, the protrusion may be inserted in the aperture and engaged therein in the closed position, and wherein said application torque may be applied to the lid about the living hinge (16) to alter the operational configuration of the lid (14) in relation to the body portion (12), from a closed configuration to an open configuration.

38. The system of claims 36 or 37, wherein said at least one adjustable setting of the injection molding system (100) is a setting of a flip-top closing mechanism of the injection molding system.

39. The system of claims 36, 37 or 38, wherein the system comprises a part of the injection mold having an adjustable dimension such that the at least one adjustable setting of the injection molding system (100) comprises an adjustable dimension setting of at least part of the injection mold.

40. The system of any one of claims 36 to 39 wherein said system further comprises a regional temperature device, said regional temperature device (310A', 31 OB', 312A', 312B') having a setting operable to adjust the temperature of a region of the injection mold.

41. The system of claim 40 wherein said regional temperature device (310A', 31 OB', 312A', 312B') is positioned near one of the mold portion that forms the protrusion (30) and the mold portion that forms the aperture (26), in the formed flip-top closure (1).

42. The system of claim 41 wherein said regional temperature device is a first regional temperature device (312A', 312B') positioned near the mold portion that forms the protrusion and wherein said system further comprises a second regional temperature device (310A', 310B') positioned near the mold portion that forms the aperture.

43. The system of claim 40 wherein the regional temperature device is a heater.

44. The system of claim 42 wherein the first and second regional temperature devices each comprise a heater.

45. A method for forming a first part associated with a closure (10, 400, 510, 511), said method performed using an injection molding system having an injection mold with at least one molding cavity, wherein in use, said first part is operable to be movable relative to a second part upon application of an application force, between a first operational configuration and a second operational configuration, wherein the method comprises:

adjusting at least one setting of the injection molding system so that the application force is defined; and

molding the first part in the injection mold with the at least one setting of the injection molding system adjusted.

46. A method as claimed in claim 45 wherein said first part (411) has an interface surface (411a) and said second part (414) has an interface surface 9414a), wherein in use, said interface surface (411a) of said first part (411) and said interface surface (414a) of said second part (414) are in frictional engagement with each other, and wherein the application force is a force required to overcome the frictional engagement between the interface surface of said first part and the interface surface of said second part.

47. A method as claimed in claims 45 or 46 wherein said method comprises a method for forming a closure (510, 511) with said injection molding system, a formed closure comprising said first part (510), and said formed closure being movable upon application of an application force at a position on said first part (510), between a closed position in which the first part is engaged with said second part (511) and an open position in which the first part (510) is disengaged from said second part (511), wherein, the method comprises:

adjusting at least one setting of the injection molding system so that the application force of the formed closure (510, 511) is defined; and

molding the closure in the injection mold with the at least one setting of the injection molding system adjusted.

48. A method as claimed in claims 45, 46 or 47 wherein said second part (511) is defined on a container.

49. A method as claimed in claims 45, 46 or 47 wherein said second part is defined as a part of said closure.

50. A method as claimed in claim 49 wherein first part is a lid of the closure and the second part is a body portion of the closure.

51. A method as claimed in any one of claims 45 to 50 wherein said method is for forming a plurality of closures in a plurality of molding cavities in said injection molding system, each of said formed closures having a first part and a second part, and each of said formed closures being movable upon application of an application force at a position on said first part, between a closed position in which the first part is engaged with said second part and an open position in which the first part is disengaged from said second part, wherein, the method comprises:

adjusting a first setting associated with a first molding cavity of the injection molding system so that the application force of the formed closure of a first molding cavity is defined; and

molding the closure in the injection mold with the first setting of the injection molding system adjusted;

adjusting a second setting associated with a second molding cavity of the injection molding system so that the application force of the formed closure of a second molding cavity is defined; and

52. A method as claimed in claims 47 or 51, further comprising:

adjusting a setting of a closing mechanism of the injection molding system so that the application force of the formed closure is defined;

moving the first part and second part relative to each other to said closed position of the formed closure with the closing mechanism while the formed closure remains in the injection mold; and

ejecting the formed closure from the injection mold.

53. A method as claimed in any one of claims 47 to 52 wherein adjusting at least one setting of the injection molding system comprises adjusting a dimension of at least part of the injection mold so that the application force of the formed closure is defined.

54. A method as claimed in claim 53 wherein said adjusting a dimension of at least part of the injection mold so that the application force of the closure is defined comprises adjusting a dimension associated with a part of the injection mold that forms an interface surface on said first part of the formed closure.

55. A method as claimed in claim 54 further comprising: adjusting a second setting of the injection molding system, said second setting comprising a dimension of a second part of the injection mold; and molding the closure in the injection mold with the second setting of the injection molding system adjusted.

56. A method as claimed in claim 55 wherein said adjusting a second setting of the injection molding system comprises adjusting a dimension associated with a second part of the injection mold that forms an interface surface on said second part of the formed closure.

57. A method as claimed in any one of claims 47 to 56, wherein said adjusting at least one setting of the injection molding system comprises adjusting a temperature of at least part of the injection mold that forms at least part of the first part so that the application force of the formed closure is defined at a threshold.

58. A method as claimed in any one of claims 47 to 57, wherein said adjusting at least one setting of the injection molding system comprises adjusting a temperature of at least part of the injection mold that forms at least part of the second part so that the opening force of the formed closure is defined at a threshold.

59. An injection molding system operable for forming a first part associated with a closure, said injection molding system having an injection mold with at least one molding cavity, wherein in use, said first part is operable to be movable relative to a second part upon application of an application force, between a first operational configuration and a second operational configuration, the injection molding system comprising at least one adjustable setting of the injection molding system operable to be adjustable so that the application force is defined.

60. An injection molding system as claimed in claim 59 wherein said injection molding system is operable for forming a closure, and wherein a formed closure formed in said at least one molding cavity has a first part and said formed closure being movable upon application of an application force at a position on said first part, between a closed position in which the first part is engaged with a second part and an open position in which the first part is disengaged from said second part, the injection molding system comprising at least one adjustable setting of the injection molding system operable to be adjustable so that the application force of the formed closure is defined.

61. An injection molding system as claimed in claim 59 wherein said system is operable for forming a flip-top closure (10, 500), wherein said first part is a body portion (12, 511) and said second part is a lid (14, 510).