MOLDS, MOLD ASSEMBLIES AND STACK COMPONENTS

FIELD OF THE INVENTION

This invention relates generally to molding apparatus and associated methods. More specifically, although not exclusively, this invention relates to mold stacks, mold assemblies, molds, molding systems for molding preforms and other articles, for example tubular articles, and to associated methods.

BACKGROUND OF THE INVENTION

Molding is a process by virtue of which a molded article can be formed from molding material, such as a plastics material, by using a molding system, such as an injection molding system or a compression molding system. Various molded articles can be formed by using such molding processes including, for example, preforms which can be formed from polyethylene terephthalate (PET) material. Such preforms are capable of being subsequently blown into a container, for example a beverage container, bottle, can or the like.

As an illustration, injection molding of preforms involves heating PET material (or other suitable molding material for that matter) to a homogeneous molten state and injecting, under pressure, the so-melted material into a molding cavity defined, at least in part, by a female cavity piece and a male core piece. Typically, the female cavity piece is mounted to a cavity plate and the male core piece is mounted to a core plate of a mold. The cavity plate and the core plate are urged together and are held together by clamp force, the clamp force being sufficient to keep the cavity and the core pieces together against the pressure of the injected material. The molding cavity has a shape that substantially corresponds to a final cold-state shape of the molded article to be molded. The so-injected material is then cooled to a temperature sufficient to enable removal of the so-formed molded article from the molding cavity. When cooled, the molded article shrinks inside of the molding cavity and, as such, when the cavity and core plates are urged apart, the molded article tends to remain associated with the core piece.

Accordingly, by urging the core plate away from the cavity plate, the molded article can be subsequently demolded by ejecting it off the core piece. Ejection structures are known to assist in removing the molded articles from the core halves. Examples of the ejection structures include stripper plates, stripper rings and neck rings, ejector pins, etc.

When dealing with molding a preform that is capable of being subsequently blown into a beverage container, one consideration that needs to be addressed is forming a so-called "neck region". Typically and as an example, the neck region includes (i) engaging features, such as threads (or other suitable structure), for accepting and retaining a closure assembly (ex. a bottle cap), and (ii) an anti-pilferage assembly to cooperate, for example, with the closure assembly to indicate whether the end product (i.e. the beverage container that has been filled with a beverage and shipped to a store) has been tampered with in any way. The neck region may comprise other additional elements used for various purposes, such as to cooperate with parts of the molding system (ex. a support ledge, etc.). As is appreciated in the art, the neck region cannot be formed easily by using the cavity and core halves. Traditionally, split mold inserts (sometimes referred to by those skilled in the art as "neck ring") have been used to form the neck region.

A typical molding insert stack assembly that can be arranged (in use) within a molding machine includes a split mold insert pair that, together with a mold cavity insert, a gate insert and a core insert, defines a molding cavity. Molding material can be injected into the molding cavity from a source of molding material via a receptacle or port in the gate insert to form a molded article. In order to facilitate forming of the neck region of the molded article and subsequent removal of the molded article therefrom, the split mold insert pair comprises a pair of complementary split mold inserts that are mounted on adjacent slides of a slide pair. The slide pair is slidably mounted on a top surface of a stripper plate.

As commonly known, the stripper plate is configured to be movable relative to the cavity insert and the core insert, when the mold is arranged in an open configuration. As such, the slide pair, and the complementary split mold inserts mounted thereon, can be driven laterally, via a cam arrangement or any other suitable known means, for the release of the molded article from the molding cavity. One of the functions performed by the split mold insert pair is to assist in ejecting the molded article off the core insert by "sliding" the molded article off the core insert.

SUMMARY OF THE INVENTION

The present invention seeks to provide an alternative arrangement for securing stack components of a mold for molding articles, specifically but not exclusively tubular articles such as preforms. This invention is directed, in particular but not exclusively, to mold stacks, molds, mold assemblies, molding systems and associated methods. In the case of tubular articles such as preforms, the articles may have a base portion at a closed end, a neck finish at an open end and a body portion therebetween. The neck finish may include one or more radial flanges, which may extend outwardly. The neck finish may include engaging features, such as threads or a snap fit finish. The preform and/or neck finish may comprise any one or more other features described above in relation to known preform designs. In addition, any of the foregoing features described in relation to known mold stacks, molds and molding systems may be incorporated within mold stacks, molds and molding systems according to the invention, insofar as they are consistent with the disclosure herein.

According to a first broad aspect of the invention, there is provided a mold assembly, e.g. a core plate assembly, for incorporation into a mold, e.g. a preform mold, the assembly comprising a core plate and a plurality of core inserts mounted to the core plate by fastening means and/or when the assembly is incorporated in an assembled mold, wherein the fastening means is operable, from a rear side of the core plate and/or without access to a front side of the core plate and/or when the assembly is incorporated in an assembled mold, to secure the core inserts to a fixed condition, e.g. in which the core inserts are immovable relative to the core plate.

The fastening means may be operable to secure the core inserts from a movable or floating condition, e.g. in which the core inserts are able to slide relative to the core plate along a sliding interface therebetween, to the fixed condition and/or to an aligned condition.

Yet another aspect of the invention provides a mold assembly, e.g. a core plate assembly, for incorporation into a mold, e.g. a preform mold, the assembly comprising a core plate and a plurality of core inserts mounted to the core plate by fastening means, wherein the fastening means is operable, when the assembly is incorporated in an assembled mold, to secure the core inserts from a movable or floating condition, e.g. in which the core inserts are able to slide relative to the core plate along a sliding interface therebetween, to a fixed and/or aligned condition, e.g. in which the core inserts are immovable relative to the core plate.

At least one or each core insert may be mounted to a front surface of the core plate. At least one or each core insert may have a mounting surface, which may cooperate with the front surface of the core plate to provide the or a sliding interface. The fastening means may be operable without access to the front of at least some of the core inserts. The fastening means may be operable from a rear side of the core plate.

The fastening means may comprise one or more threaded holes, which may be on the rear side of at least one or each core insert. The threaded holes may receive respective threaded fasteners, which may extend through holes in the core plate and/or threadedly engage the threaded holes of the core inserts.

The core insert may comprise a base. The base may comprise a first end, which may include the mounting surface, and/or a second end, which may include a molding surface, e.g. for molding an internal surface of a part, such as a preform. The core insert may comprise one or more threaded holes, which may be in the mounting surface, e.g. for threadedly engaging a fastener. The fastener may be operable, e.g. when the core insert is incorporated within an assembled mold, to secure the core insert from the movable or floating condition to the fixed and/or aligned condition.

Another aspect of the invention provides a core insert, e.g. a preform core insert, comprising a base with a first end comprising a mounting surface and a second end comprising a molding surface for molding an internal surface of a part, e.g. a preform, wherein the core insert comprises one or more threaded holes in the mounting surface for threadedly engaging a fastener which is operable, from a rear side of the core plate and/or without access to a front side of the core plate and/or when the core insert is incorporated within an assembled mold, to a fixed condition, e.g. in which the core insert is immovable relative to the core plate.

The one or more threaded holes may comprise a plurality of threaded holes spaced equally about a peripheral portion of the base. The outer dimension(s) of the base may be configured to minimise the pitch between adjacent cores.

The fastener may be operable to secure the core insert from a movable or floating condition, e.g. in which it is able to slide relative to a core plate of the mold along a sliding interface therebetween, to the fixed condition or to an aligned condition.

Yet another aspect of the invention provides a core insert, e.g. a preform core insert, comprising a base with a first end comprising a mounting surface and a second end comprising a molding surface for molding an internal surface of a part, e.g. a preform, wherein the core insert comprises one or more threaded holes in the mounting surface for threadedly engaging a fastener which is operable, when the core insert is incorporated within an assembled mold, to secure the core insert from a movable or floating condition, e.g. in which it is able to slide relative to a core plate of the mold along a sliding interface therebetween, to a fixed and/or aligned condition, e.g. in which the core insert is immovable relative to the core plate.

The core insert may comprise a molding surface, which may describe part of a top sealing surface of a preform. The core insert may comprise a taper, which may extend from the molding surface. The core insert may comprise an annular support surface, which may extend radially from the taper. The taper may be configured to engage, in use, with cooperating tapers of a pair of split mold inserts, e.g. to describe a parting line therebetween. The annular support surface may engage and/or support, in use, a facing surface of the split mold inserts.

Another aspect of the invention provides a core insert, e.g. a preform core insert, the core insert comprising a molding surface describing part of a top sealing surface of a preform, a taper extending, e.g. directly, from the molding surface and an annular support surface extending, e.g. directly, radially from the taper, the taper being configured to engage, in use, with cooperating tapers of a pair of split mold inserts to describe a parting line therebetween with the annular support surface engaging and supporting a facing surface of the split mold inserts.

The annular support surface may be substantially perpendicular to a longitudinal axis of the preform core insert. The taper may comprise a male taper. The annular support surface may include a recess, e.g. a shallow recess, which may be conical. The recess may be for inhibiting, in use, separation of a split mold pair engaged with the taper and annular support surface. The recess may be depressed at an angle, which may be 45 degrees or less, preferably 30 degrees or less and more preferably 20 degrees or less. The recess is more preferably depressed at an angle of 10 degrees or less, for example about 5 degrees. The recess may comprise a taper angle. The recess may comprise an included angle of 90 degrees or more, preferably 120 degrees or more and more preferably 140 degrees or more. The included angle is preferably 160 degrees or more, for example about 170 degrees.

The base may, but need not, be cylindrical or substantially cylindrical. The mounting surface may be at or provide a terminal end of the or each core insert. The mounting surface may be free of any projections, e.g. thereby to enable the core inserts to slide relative to the core plate along a sliding interface, for example when the core inserts are in the movable or floating condition. Alternatively, the base may comprise a spigot, which may extend from the mounting surface and/or may be received or receivable within a seat of the or a core plate. At least one or each core insert, e.g. the mounting surface thereof, may comprise an opening for receiving a core cooling tube. The fastening means, for example the threaded holes, may be spaced equally between the opening and the periphery of the base.

At least one or each core insert, e.g. the mounting surface thereof, may comprise a recess, which may surround the opening and may define therebetween a shutoff surface. At least one or each core insert, e.g. the mounting surface thereof, may comprise a seal surrounding the opening, e.g. for sealing against the front surface of the core plate. At least one or each core insert, e.g. tthe mounting surface thereof, may comprise a groove surrounding the opening for receiving the seal, which may comprise an O-ring seal. The seal and/or groove may be located on or in the shutoff surface.

At least one or each core insert may comprise a primary core insert and/or a core ring.

Another aspect of the invention provides a primary core insert, e.g. for use in the core insert as described above. The primary core insert may include a base for mounting to the core plate. The primary core insert may include a molding surface for molding an internal surface of a preform. The primary core insert may include an interface portion between the base and the molding surface. The interface portion may be substantially cylindrical and/or may comprise a draft or taper.

Another aspect of the invention provides a core ring, e.g. for use in a core insert as described above. The core ring may comprise a flange portion, which may be cylindrical or substantially cylindrical. The core ring may comprise a taper, e.g. for engaging, in use, cooperating tapers of a pair of split mold inserts. The core ring taper may comprise a frusto-conical shape and/or may project from the flange portion. The core ring taper may comprise a male taper.

The core ring, e.g. the flange and/or taper thereof, may receive, in use, the interface portion of the primary core insert. The core ring taper and/or flange may surround, in use, the interface portion of the primary core insert. The core ring may comprise an internal interface surface, e.g. for engaging, in use, the interface portion of the primary core insert. The core ring flange may comprise or provide, in use, an extension to the base of the primary core insert. The core ring flange may be configured to abut, in use, the base of the or a primary core insert.

At least one or each core insert may comprise a vent passage. Where the core insert comprises a two-part core insert, at least part of the vent passage may be described at least partially between the primary core insert and the core ring. At least part of the vent passage may be described, or partly described, by the primary core insert and/or the core ring. At least part of the vent passage may be described, or partly described, by the interface portion of the primary core insert and/or the internal interface surface of the core ring.

The core ring may be press-fit to the interface portion or otherwise secured directly to the primary core insert. The interface portion of the primary core insert may comprise a recess, which may cooperate, in use, with the internal interface surface of the or a core ring, e.g. to describe at least part of the or a vent passage.

The internal interface surface of the core ring may comprise a recess, which may cooperate, in use, with the interface portion of the primary core insert, e.g. to describe at least part of the vent passage. The core ring may comprise a hole or drilling, which may describe at least part of the or a vent passage. The hole or drilling may extend from the internal interface surface to the core ring taper.

At least part of the or a further vent passage may be described by the core ring taper, e.g. a taper surface thereof. The male taper may comprise a recess, e.g. on an outer surface thereof, which may describe at least part of the or the further vent passage.

The assembly may comprise one or more coolant diverters and/or one or more core cooling tubes. The or each coolant diverter may be received in a respective seat of the core plate. The or each core cooling tube may be received in a respective core insert.

Another aspect of the invention provides a core insert assembly for a mold, e.g. a preform mold, the assembly comprising a core insert, e.g. as described above, and a core cooling tube and/or a coolant diverter.

The coolant diverter may comprise a body, which may describe at least part of first and second cooling channels. The coolant diverter may comprise a locator, e.g. for engaging a locator of the core plate seat. The first cooling channel may comprise an inlet portion, e.g. for receiving cooling fluid from a cooling circuit of the core plate. The first cooling channel ma comprise an outlet portion, which may extend at an angle, for example substantially orthogonal or perpendicular, relative to the inlet portion, e.g. for supplying the cooling fluid to a core insert. The second cooling channel may comprise an inlet, e.g. for receiving cooling fluid from the core insert. The second cooling channel may comprise an outlet, e.g. for delivering the cooling fluid to the cooling circuit of the core plate. The locator may be configured to align, in use, the inlet portion of the first cooling channel with the cooling circuit of the core plate. The locator may be configured to inhibit, in use, removal of the diverter when the diverter is received within the core plate seat. The locator may comprise a snap fit connector.

The locator or snap fit connector may comprise a projection, which may be located on or form part of the body. The locator or snap fit connector may be receivable within the cooling circuit of the core plate. The projection may comprise an annular projection, which may be receivable within the cooling circuit of the core plate. The annular projection may comprise a lip, which may surround an opening of the inlet portion of the first cooling channel, e.g. for receipt within the cooling circuit of the core plate.

Alternatively, the locator or snap fit connector may comprise a recess, e.g. for receiving a projection of the core plate seat. At least part of the second cooling channel may be described, in use, between an outer surface of the coolant diverter and the core plate seat. The body may be substantially cylindrical in shape. The inlet portion of the first cooling channel may comprise a radial bore. The outlet portion of the first cooling channel may comprise an axial bore. At least part of the second cooling channel may be described by a recess in the body. The first cooling channel may comprise a curved transition portion, which may join the radial bore to the axial bore.

The coolant diverter may comprise one or more spacers, e.g. for engaging the core plate seat and/or to center the outlet portion of the first cooling channel therein. The outlet portion of the first cooling channel may be described at least in part by a tubular or part-tubular portion. At least one of the spacers may comprises a part-circumferential wall, which may surround and/or be spaced from at least part of the tubular or part-tubular outlet portion of the first cooling channel.

Additionally or alternatively, at least one of the spacers may comprise a fin, which may project radially with respect to the outlet portion of the first cooling channel. The fin may comprise an axial projection and/or may extend axially and/or along at least part of the outlet portion of the axial bore or first cooling channel.

The coolant diverter may comprise a connector, e.g. for engaging a core cooling tube thereto. The connector may comprise a threaded hole. The connector may comprise a threaded portion of the axial bore or outlet portion of the first cooling channel. Alternatively, the connector may comprise any other suitable type of connection, such as a bayonet, push fit or snap fit configuration.

The core cooling tube may comprise an inlet portion, e.g. for receiving cooling fluid from a cooling circuit of a core plate.

The core cooling tube may comprise an open end, e.g. for directing cooling fluid to an internal surface of a core insert. The core cooling tube may comprise an outlet portion, which may comprise the open end. The open end may comprise an aperture. The aperture may describe a flow area, which may be less than a flow area through the outlet portion.

Another aspect of the invention provides a core cooling tube for a preform mold, the core cooling tube comprising an inlet portion for receiving cooling fluid from a cooling circuit of a core plate and an outlet portion with an open end for directing cooling fluid to an internal surface of a core insert, wherein the open end comprises an aperture describing a flow area that is less than the flow area through the outlet portion.

The outlet portion may taper, for example toward the open end. The outlet portion may be truncated, for example to describe the aperture. The outlet portion may comprise, or the end may be described by, a truncated cone or dome, which may describe the aperture. The end may be for directing cooling fluid to a conical or domed internal surface of a core insert. The end may comprise a conical or domed internal surface and/or a conical or domed external surface.

The truncated outlet portion may be substantially spherical or ellipsoidal. The aperture may be substantially circular or elliptical. The open end may be shaped and/or configured to approximate an internal surface, e.g. a conical or domed internal surface, of a core insert.

The core cooling tube may be integral with the coolant diverter. The core cooling tube may be formed by an additive manufacturing process.

The core cooling tube may comprise one or more, e.g. a plurality of, spacer elements, which may project from an outer surface of the core cooling tube. The spacer element(s) may be suitable or configured for centering, in use, the core cooling tube within a core insert. One or more of the spacer element(s) may be located at or adjacent the open end of the core cooling tube. One or more of the spacer element(s) may be located at one or more intermediate locations, e.g. between the open end and the coolant diverter. The or each spacer element may comprise a spacer vane.

At least two of the spacer elements or vanes may be spaced axially relative to each other, e.g. along the core cooling tube. The spacer elements or vanes may comprise a plurality of projections spaced equally about the periphery of the core cooling tube. The plurality of spacer elements or vanes may comprise one or more first spacer element(s) or vane(s) and one or more second spacer element(s) or vane(s). The first spacer element(s) or vane(s) may be at a first axial position and/or the second spacer element(s) or vane(s) may be at a second axial position, which may be different to the first axial position. The plurality of equally spaced spacer element(s) or vane(s) may comprise alternating first and second spacer element(s) or vane(s).

The core cooling tube may comprise an enlarged portion, which may be shaped and/or configured to cooperate with a transition in the internal surface of a core insert. One or more, e.g. a plurality of the spacer element(s) or vane(s) may be on and/or project from the enlarged portion. The enlarged portion may be at an intermediate location of the core cooling tube and/or between the open end of the core cooling tube and the coolant diverter.

Another aspect of the invention provides a mold, e.g. a preform mold, comprising a core plate, a cavity plate and a plurality of mold stacks mounted between the core and cavity plates, each mold stack comprising a core insert mounted to the core plate by fastening means, a cavity insert mounted to the cavity plate and split mold inserts mounted between the core and cavity inserts, wherein the fastening means is operable, from a rear side of the core plate and/or without access to a front side of the core plate and/or when the mold is assembled, to secure the core inserts to a fixed condition, e.g. in which the core inserts are immovable relative to the core plate.

The fastening means may be operable to secure the core inserts from a movable or floating condition, e.g. in which the core inserts are able to slide relative to the core plate along a sliding interface therebetween, to the fixed condition and/or an aligned condition.

Yet another aspect of the invention provides a mold, e.g. a preform mold, comprising a core plate, a cavity plate and a plurality of mold stacks mounted between the core and cavity plates, each mold stack comprising a core insert mounted to the core plate by fastening means, a cavity insert mounted to the cavity plate and split mold inserts mounted between the core and cavity inserts, wherein the fastening means is operable, when the mold is assembled, to secure the core inserts from a movable or floating condition, e.g. in which the core inserts are able to slide relative to the core plate along a sliding interface therebetween, to a fixed and/or aligned condition, e.g. in which the core inserts are immovable relative to the core plate.

The mold may comprise an injection mold, e.g. a preform injection mold. The mold may comprise any one or more features of the aforementioned core plate assembly, core insert assembly, core insert, primary core insert and/or core ring.

The mold may comprise one or more fasteners, which may be for securing the core plate to the cavity plate. At least one of the fasteners may secure a central portion of the core plate to a central portion of the cavity plate. Preferably, the mold comprises a plurality or array of fasteners, a plurality of which secure a central portion of the core plate to a central portion of the cavity plate. A plurality of the fasteners may secure one or more peripheral portions of the core plate to corresponding peripheral portion(s) of the cavity plate. At least one or each fastener may extend through the core plate and/or may threadedly engage the cavity plate.

Another aspect of the invention provides a molding system comprising a mold as described above. The molding system may comprise one or more of a melt distributor, an injection molding machine, a material supply system and a part removal and/or post mold cooling apparatus.

According to a another broad aspect of the present invention, there is provided a method of securing a plurality of core inserts to a core plate of a mold, e.g. a preform mold, the method comprising: mounting a plurality of core inserts to the core plate; and securing the core inserts into a fixed condition from a rear side of the core plate and/or without access to a front side of the core plate.

The method may comprise mounting a plurality of core inserts to the core plate in a movable or floating condition. The method may comprise aligning the core inserts relative to other mold inserts. The method may comprise securing the core inserts into the fixed condition or into an aligned condition.

According to yet another broad aspect of the present invention, there is provided a method of aligning a plurality of core inserts mounted to a core plate of a mold, e.g. a preform mold, the method comprising: mounting a plurality of core inserts to the core plate in a movable or floating condition; aligning the core inserts relative to other mold inserts; and securing the core inserts into a fixed and/or aligned condition.

The core inserts may be able to slide relative to the core plate, e.g. along a sliding interface therebetween, e.g. when they are in the movable or floating condition. The core inserts may be immovable relative to the core plate and/or aligned with the other mold inserts when they are in the fixed and/or aligned condition.

Aligning the core inserts relative to the other mold inserts may comprise bringing together the core inserts and the other mold inserts into a closed configuration, e.g. in which the core inserts are engaged and/or in contact with the other mold inserts. Aligning the core inserts relative to the other mold inserts may comprise bringing together and separating the core inserts and the other mold inserts one or more times, e.g. more than once. Aligning the core inserts relative to the other mold inserts may comprise repeatedly bringing together and separating the core inserts and the other mold inserts.

Securing the core inserts to the fixed, aligned condition may be performed with the mold inserts in the closed configuration, e.g. with the core inserts engaged and/or in contact with the other mold inserts. The method may comprise securing the mold inserts in the closed configuration before securing the core inserts to the fixed, aligned condition.

Bringing together the core inserts and the other mold inserts into a closed configuration may comprise bringing together the core plate and one or more plates to which the core inserts and/or other inserts are mounted. The other inserts may comprise cavity inserts. Bringing together the core inserts and the other mold inserts into a closed configuration may comprise bringing together the core plate and a cavity plate of the mold, e.g. to which a plurality of cavity inserts are mounted. Securing the core inserts in the fixed, aligned condition may be performed with the core plate mounted to the cavity plate.

The method may comprise securing the core plate relative to the one or more plates, e.g. the cavity plate, by one or more fasteners, for example before securing the core inserts to the fixed, aligned condition. Securing the core plate relative to the other plate(s) may comprises threadedly engaging one or more fasteners, which may extend through a central portion of the core plate, with a threaded hole in a central portion of at least one of the other plate(s). Securing the core plate relative to the other plate(s) may comprises threadedly engaging one or more fasteners extending through a peripheral portion of the core plate, with a threaded hole in a peripheral portion of the or one of the other plate(s), e.g. the cavity plate.

The core plate and cavity plate may be brought together with one or more further plates, e.g. a stripper plate, therebetween. The other mold inserts may comprise split mold inserts. The stripper plate may have a plurality of split mold inserts mounted thereto. The core plate and cavity plate may be brought together to align the core inserts relative to the other mold inserts, for example with the cavity inserts secured to the cavity plate in a fixed condition.

The split mold inserts may be movably or fixedly mounted to the stripper plate, e.g. when the core plate and cavity plate are brought together to align the core inserts relative to the other mold inserts. The split mold inserts may be movably mounted in a floating condition, for example to slides which may be movably mounted to the stripper plate, when the core plate and cavity plate are brought together to align the core inserts relative to the other mold inserts. The split mold inserts may be mounting in a floating manner by a retainer assembly of the kind described in our co-pending application number PCT/CA2018/050693.

The core inserts may be mounted to a front side of the core plate. Securing the core inserts to the fixed, aligned condition may be performed from a rear side of the core plate and/or without access to a front side of the core plate. The method may comprise tightening or torqueing fastening means, e.g. one or more fasteners, from a rear side of the core plate. The fastening means may extend through or around the core plate and engage the core inserts. The fastening means may comprise one or more fasteners, such as bolts, which may extend through respective holes in through the core plate and/or engage respective threaded holes in the core inserts.

Another aspect of the invention provides a computer program element comprising and/or describing and/or defining a three-dimensional design for use with a simulation means or a three-dimensional additive or subtractive manufacturing means or device, e.g. a three-dimensional printer or CNC machine, the three-dimensional design comprising one or more mold components described above.

Another aspect of the invention provides a method of assembling a mold assembly or mold as described above. Various steps and features of the method will be apparent to the skilled person.

Another aspect of the invention provides a method of molding articles. The method may comprise the use of one of the aforementioned mold stacks, molds, mold assemblies or molding systems. The method may comprise any one or more features or steps relevant to or involving the use of any feature of any of the aforementioned mold stacks, molds, mold assemblies or molding systems.

For the avoidance of doubt, any of the features described herein apply equally to any aspect of the invention. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. For the avoidance of doubt, the terms“may”,“and/or”,“e.g.”,“for example” and any similar term as used herein should be interpreted as non-limiting such that any feature so-described need not be present. Indeed, any combination of optional features is expressly envisaged without departing from the scope of the invention, whether or not these are expressly claimed. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any

originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

FIG. 1 depicts a preform mold assembly according to an embodiment of the invention;

FIG. 2 depicts the preform mold assembly of FIG. 1 with the melt distributor omitted;

FIG. 3 depicts the core plate assembly of the preform mold assembly of FIGs 1 and 2 with one core omitted and another core assembly shown exploded;

FIG. 4 depicts an enlarged view of the region of FIG. 3 which includes the exploded core assembly;

FIG. 5 depicts a side view of part of the core plate assembly of FIGs. 3 and 4 illustrating the mounting of one of the cores to the core plate;

FIG. 6 depicts a section view through one of the core assemblies and an adjacent portion of the core plate to which the core assembly is secured;

FIG. 7 depicts a core cooling tube assembly of the core assembly of FIG. 6 shown from a first side;

FIG. 8 depicts the core cooling tube assembly of FIG. 7 shown from a second side;

FIG. 9 depicts an alternative, unitary core cooling tube assembly shown from a first side;

FIG. 10 depicts the core cooling tube assembly of FIG. 9 shown from a second side;

FIG. 11 depicts a section view along a central, axial plane through the core cooling tube assembly of FIGs. 9 and 10;

FIG. 12 depicts a further alternative, unitary core cooling tube assembly shown from a first side;

FIG. 13 depicts the core cooling tube assembly of FIG. 12 shown from a second side;

FIG. 14 depicts a section view along a central, axial plane through the core cooling tube assembly of FIGs. 12 and 13;

FIG. 15 depicts a yet further alternative, unitary core cooling tube assembly shown from a first side;

FIG. 16 depicts the core cooling tube assembly of FIG. 15 shown from a second side;

FIG. 17 depicts a section view along a central, axial plane through the core cooling tube assembly of FIGs. 15 and 16;

FIG. 18 depicts an alternative, two-part core insert for use in the preform mold assembly of FIGs. 1 and 2;

FIG. 19 depicts the two-part core insert of FIG. 18 in an exploded view;

FIG. 20 depicts a section view of a stack assembly incorporating the two-part core insert of FIGs. 18 and 19 along a central, axial plane;

FIG. 21 depicts the moving part of the preform mold assembly of FIGs. 1 and 2, including the core plate assembly and stripper plate assembly;

FIG. 22 depicts the stripper plate of the stripper plate assembly of the moving part shown in

FIG. 21;

FIG. 23 depicts an exploded view of a pair of slides of the stripper plate assembly of FIG. 18;

FIG. 24 depicts three neck ring halves and their associated retaining assemblies that secure them to the slides;

FIG. 25 depicts an enlarged view of part of the stripper plate assembly of the moving half of

FIG. 21 with the neck ring pairs omitted to expose the slides;

FIG. 26 depicts an enlarged view of FIG. 25 with the connecting bars omitted and illustrating the insertion of the guide shaft;

FIG. 27 depicts the cavity plate assembly of the preform mold assembly of FIGs. 1 and 2 with one of the cavity assemblies removed therefrom;

FIG. 28 depicts one of the cavity assemblies of the cavity plate assembly of FIG. 27;

FIG. 29 depicts the cavity insert of the cavity assembly of FIG. 28 with the gate insert omitted;

FIG. 30 illustrates the cooling channels in segment A-A of the cavity insert of FIG. 29;

FIG. 31 depicts the gate insert of the cavity assembly of FIG. 28;

FIG. 32 depicts one of the retaining pins of the cavity assembly of FIG. 28;

FIG. 33 depicts a partial section view of the cavity plate assembly through a column of cavity inserts of the cavity plate assembly of FIG. 27;

FIG. 34 depicts a partial section view of the cavity plate assembly through a row of cavity inserts of the cavity plate assembly of FIG. 27;

FIG. 35 depicts an enlarged view of the bypass and retaining pin region of the partial section view of FIG. 34;

FIG. 36 depicts a similar view to FIG. 35 illustrating an alternative bypass channel configuration;

FIG. 37 depicts a similar view to FIGs. 35 and 36 illustrating an alternative retaining pin configuration in which the bypass channel is described between the retaining pin and the cavity insert;

FIG. 38 depicts a partial section view of the gate region of an alternative cavity plate assembly in which a gate pad is provided between the nozzle tip and gate insert;

FIG. 39 depicts an exploded view of the gate pad and gate insert of FIG. 38;

FIG. 40 depicts a partial section view of the mold of FIG. 1 illustrating one mold stack, but with the melt distributor and core cooling tube assembly both omitted;

FIG. 41 depicts an enlarged view of area B of FIG. 39 illustrating the gap between the stripper plate and the core plate;

FIG. 42 depicts the cavity plate assembly of FIG. 27 being lowered onto the moving part illustrated in FIG. 21 during assembly; and

FIG. 43 depicts part of the alignment procedure for aligning the cores and neck rings relative to the cavities of the cavity plate assembly.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGs. 1 and 2, there is depicted a non-limiting embodiment of a preform mold assembly 100 according to the invention, which includes forty-eight cavities in this embodiment. The mold assembly 100 includes a first, moving part 110 for mounting to the moving platen (not shown) of an injection molding machine (not shown) and a second, stationary part 120 for mounting to the stationary platen (not shown) in the usual way. The first, moving part 110 includes a core plate assembly 200 and a stripper plate assembly 300. The second, stationary part 120 includes a cavity plate assembly 400 and a melt distributor 500, commonly referred to as a hot runner. In this

embodiment, the melt distributor 500 is of a conventional type. This invention is particularly concerned with the product specific assembly 130 shown in FIG. 2, commonly referred to as the‘cold half 130. The cold half 130 includes the core plate assembly 200, stripper plate assembly 300 and cavity plate assembly 400.

As shown more clearly in FIGs. 3 and 4, the core plate assembly 200 includes a core plate 210, a pair of cam plates 220, four guide pins 230 and a plurality of core assemblies 240. The core plate 210 is substantially rectangular in plan with scalloped comers 211, for accommodating the tiebars (not shown) of an injection molding machine (not shown) within which the mold is mounted. The core plate 210 also includes four guide pin holes 212 through its thickness, which are horizontally inboard of each scalloped comer 211 and securely receive the guide pins 230. The core plate 210 also includes a plurality of ejector holes 213 through its thickness, for accommodating ejector pins (not shown).

A network of cooling channels 214a, 214b is included within the core plate 210, which feed into a plurality of cooling channel seats 215 in a front face CRF of the core plate 210 (as illustrated in FIG. 6). The cooling channel seats 215 are arranged in an array of six vertical columns and eight horizontal rows. Each seat 215 is surrounded by three core mounting holes 216, which extend through the thickness of the core plate 210 and are counterbored on a rear face CRR of the core plate 210. An array of coupling bolts 217 are also inserted into holes in the core plate 210, which are also counterbored on the rear face CRR. One of the cam plates 220 is bolted to a central, lower region of the front face CRF of the core plate 210 and includes a pair of cam slots 221 on its upper surface. The other cam plate 220 is bolted to a central, upper region of the front face CRF of the core plate 210 and includes a similar pair of cam slots 221 on its lower surface. Both cam plates 220 have the same configuration, varying only in their orientation. The cam slots 221 of each cam plate 220 extend perpendicularly from the front face CRF and converge toward the free end of the cam plate 220.

As illustrated more clearly in FIGs. 4 to 8, each core assembly 240 includes a hollow core insert 250 and a core cooling tube assembly 260, 270. In this example, the core cooling tube assembly 260, 270 includes a coolant diverter 260 received in one of the cooling channel seats 215 of the core plate 210 and a core cooling tube 270 releasably secured to the coolant diverter 260 and received within the hollow core insert 250.

Each core insert 250 includes a substantially cylindrical base 251 and a molding portion 252 joined to the base 251 by a taper 253. The molding portion 252 has an outer molding surface 252a, for molding an inner surface of a preform in the usual way, a tapering transition region 252b for molding a transition region between neck and body regions of the preform and a top sealing surface portion TSS for molding part of the top sealing surface of a preform. The core taper 253 extends from the top sealing surface portion TSS to a front surface 251a of the base 251 and includes a single, male taper 253 for a stack configuration known in the art as a so-called‘cavity-lock’ design. However, it will be appreciated that the core insert 250 may be of the so-called‘core-lock’ design without departing from the scope of the invention.

In this example, each core insert 250 includes a substantially planar mounting surface 254 and three threaded blind holes 255 extending from the mounting surface 254. The core inserts 250 are therefore mounted from the rear, or rear mounted, whereby bolts 218 are inserted into the core mounting holes 216 from the rear face CRR of the core plate 210 and threadedly engage the threaded holes 255 of the core inserts 250. This is illustrated in FIG. 5. This rear mounting enables the core inserts 250 to be secured from the rear of the core plate 210. As such, the pitch between the core inserts 250 can be reduced without obstructing access to the bolts 218, as would be the case with traditional core inserts having a flange with through holes for receiving front mounted bolts 218.

As discussed in more detail below, this rear mounting, in combination with the substantially planar mounting surface 254, also enables the core inserts 250 to be mounted loosely to the front face CRF of the core plate 210 in a floating manner and fixed securely relative thereto after the mold 100 or cold half 130 is fully assembled. More specifically, by loosely tightening the bolts 218, the clearances between them and the core mounting holes 216 allow a degree of sliding movement between the mounting surfaces 254 of the core inserts 250 and the front face CRF. The mounting surface 254 describes a terminal end of the core insert 250 and is free of any projections, thereby to enable the core inserts 250 to slide relative to the core plate 210. With the mold 100 or cold half 130 in an assembled condition, the bolts 218 are still accessible from the rear face CRR of the core plate 210 and can therefore be torqued to fix the core inserts 250 securely to the core plate 210.

It is also envisaged, however, that the core insert 250 could be provided with a spigot that extends from the mounting surface 254. In some cases, the spigot (not shown) could be smaller than the seat 215 in the core plate 210 to enable some sliding movement therebetween. In other examples, the spigot may be substantially the same size as the seat 215 in the core plate 210.

Referring now to FIG. 6, each core insert 250 includes a central bore 250a extending from the mounting surface 254 to a hemispherical or domed, closed end adjacent the free end of the molding portion 252. The central bore 250a includes a tapering, intermediate region 250b corresponding to the tapering transition region 252b of the outer molding surface 252a. As such, the wall thickness between the central bore 250a and the outer molding surface 252a remains substantially constant along the entire molding portion 252. The mounting surface 254 also includes a shallow recess 256 surrounding the central bore 250a and defining therebetween a shutoff surface 257. The shutoff surface 257 also includes an O-ring groove 258 between the recess 256 and the central bore 250a, within which an O-ring 259 is received for sealing the interface between the central bore 250a and the core plate 210.

Each coolant diverter 260, shown in FIGs. 6 to 8, is substantially cylindrical and includes an axial blind bore 261, a radial bore 262 orthogonal to the axial bore 261 and a peripheral recess 263 parallel to the axial bore 261. The axial bore 261 extends from an upper surface 264 of the diverter 260 and terminates adjacent a lower surface 265 thereof. The axial bore 261 includes an enlarged portion 261a extending from the upper surface 264 and is threaded along part of its length to provide a connector for the core cooling tube 270. The radial bore 262 extends from the blind end of the axial bore 261 to a circumferential surface 266 on the opposite side of the diverter 260 to the peripheral recess 263. The axial bore 261 and radial bore 262 together provide a first cooling channel 261, 262 of the coolant diverter 260.

The peripheral recess 263 extends about approximately half of the circumference of the diverter 260 from the upper surface 264 toward the lower surface 265, terminating on an opposite side to the axial bore 261 such that the circumferential surface 266 extends around the entire periphery of the lower end of the diverter 260. The peripheral recess 263 cooperates with a facing surface of the cooling channel seat 215 to describe a second cooling channel of the coolant diverter 260, with an inlet described at the front face CRF of the core plate 210 and an outlet corresponding to the opening of the facing cooling channel 214b in the cooling channel seat 215.

Each coolant diverter 260 also includes a locator in the form of a retaining lip 267, which projects from the circumferential surface 266 about the periphery of the opening of the radial bore 262. The coolant diverter 260 is formed of a resilient plastics material, such that the retaining lip 267 is resiliently deformable. As such, insertion of the diverter 260 into the cooling channel seat 215 causes the retaining lip 267 to deform resiliently until both the depth and orientation of the diverter 260 within the cooling channel seat 215 are such that the radial bore 262 is aligned with a facing cooling channel 214a. Upon alignment between the radial bore 262 and the cooling channel 214a, the retaining lip 267 snaps into the cooling channel 214a and returns to its original shape. As a result, the retaining lip 267 provides a snap fit connector, acting both as a locating means, ensuring proper alignment of the radial bore 262 and cooling channel 214a, and as a retaining means for retaining the diverter 260 within the cooling channel seats 215. In this orientation, the peripheral recess 263 is aligned with a cooling channel 214b on the opposite side of the cooling channel seat 215. Whilst the retaining lip 267 is a convenient and preferred configuration, it may be replaced with a depression for receiving a projection on a facing surface of the cooling channel seat 215.

Each core cooling tube 270 includes first, second and third tubular segments 271, 272, 273. The first tubular segment 271 has a first outer diameter, the second tubular segment 272 has a second outer diameter, larger than the first outer diameter, and the third tubular segment 273 has a third outer diameter between the first and second outer diameters. The second tubular segment 272 also includes tapered ends 272a, 272b, which provide a transition between the three diameters. The outer surfaces of the second and third segments 272, 273 correspond broadly to the profile of the central bore 250a of the core insert 250 within which the core cooling tube 270 is received, which is configured to provide a predetermined flow area between the outer surface of the core cooling tube 270 and the central bore 250a to maximise cooling effectiveness.

The first tubular segment 271 includes an externally threaded lower end 271a, which is received within, and threadedly engages the internal threads of, the enlarged axial bore portion 261a of one of the coolant diverters 260. The inner diameter of the second tubular segment 272 is larger than that of the first tubular segment 271, an upper end of which is received in the second tubular segment 272. The inner diameters of the second and third tubular segments 272, 273 are substantially the same. The third tubular segment 273 is secured at its lower end to the second tubular segment 272 and includes an upper, free end which has a jagged-toothed profile including four pointed teeth 273a. The third tubular segment 273 also includes spacing vanes 273b in an intermediate portion thereof, adjacent but spaced from the teeth 273 a and aligned between each pair of teeth 273 a.

The teeth 273a ensure that any unintended forward movement of the core cooling tube 270 caused by fluid pressure flowing therethrough does not close off the flow between the core cooling tube 270 and the internal, domed end of the central bore 250a of the core insert 250. The spacing vanes 273b ensure that the core cooling tube 270 is also located centrally within the core insert 250. These spacing vanes 273b are configured to restrict radial movement of the core cooling tubes 270 by engaging against facing surfaces of the central bore 250a of the core insert 250. This arrangement maintains the position of the core cooling tube 270 within the central bore 250a, thereby ensuring that the flow profile of the cooling fluid is distributed substantially evenly therealong.

The flow direction of cooling fluid from the cooling channels 214a, 214b is indicated by the arrows in FIG. 6. As shown, cooling fluid flows from a first, inlet cooling channel 214a into the radial bore 262 of the coolant diverter 260, which acts as an inlet portion of first cooling channel 261, 262, then flows up and out of the axial bore 261, which acts as an outlet portion. The cooling fluid then flows through and out of the core cooling tube 270 to impact the center of the domed end of the central bore 250a of the core insert 250. The domed end of the core insert 250 then causes the flow to reverse, in an umbrella-like fashion to the annular gap between the outer surface of the core cooling tube 270 and the central bore 250a. However, it will be appreciated that the cooling fluid flow could otherwise flow through in the opposite direction.

The outer surface of the core cooling tube 270 corresponds broadly to the profile of the central bore 250a of the core insert 250 within the molding portion 252, thereby to provide a predetermined annular flow area, which is less than the flow area within the core cooling tube 270. As such, the cooling fluid is throttled along this annular flow area to create a turbulent flow to increase heat transfer between the molding portion 252 and the cooling fluid. The cooling fluid then flows into the peripheral recess 263 of the coolant diverter 260 and out of the cooling channel 214b on the opposite side of the cooling channel seat 215. As such, the peripheral recess 263 acts as an outlet for the cooling fluid back into the network of cooling channels 214a, 214b.

The coolant diverter 260 is formed of a resilient plastics material, such as by molding or additive manufacturing. However, the skilled person will appreciate that it is also possible to form the coolant diverter 260 from a different, more rigid plastics or metallic material, with the retaining lip 267 being provided either as an insert made of a resilient material or formed by overmolding the body of the coolant diverter 260 with a resilient material. In addition, the core cooling tube 270 is formed of

stainless steel, with the tubular segments 271, 272, 273 and spacing vanes 273b being brazed together. However, the core cooling tube 270 may instead be formed as a unitary body, such as by an additive manufacturing technique. The core cooling tube 270 may be formed of a different material, which may be a metallic or plastics material, and/or may be formed by any other suitable process.

FIGs. 9 to 11 illustrate an alternative core cooling tube assembly 1260, 1270, which is similar to the core cooling tube assembly 260, 270 described above, wherein like features are labelled with like references with the addition of a preceding‘G. As shown, this core cooling tube 1270 differs, inter alia, in that the first, second and third tubular segments 1271, 1272, 1273 and the coolant diverter 1260 are all formed integrally. The third tubular segment 1273 of the core cooling tube 1270 also includes an open end 1273a described by a truncated dome 1273a, in place of the jagged-toothed end of the core cooling tube 270 described above.

The provision of a jagged-toothed end is not necessary in this example, since the core cooling tube 1270 and coolant diverter 1260 are integral in this example and there is little risk of separation. In addition, the truncated dome 1273a includes an aperture A having a smaller diameter than the bore in the third tubular segment 1273, thereby describing a flow area which is less than the flow area through the third tubular segment 1273. As a result, cooling fluid flowing through the core cooling tube 1270 accelerates as it flows out through the aperture A. This configuration also focuses the flow directly toward a central region of the domed end of the central bore 250a of the core insert 250, before the flow is reversed as described above. This reduction in flow area to provide an accelerated, directed flow has been found to improve cooling performance.

In contrast, the teeth 273a in the core cooling tube 270 described above provide an effective increase in the flow area as compared with the flow area through the third tubular segment 273. Indeed, some of the flow of coolant fluid from the third tubular segment 273 will exit through the spaces between the teeth 273 a and be entrained with the reversed flow through the annular gap between the outer surface of the core cooling tube 270 and the central bore 250a of the core insert 250, thereby avoiding the domed end of the central bore 250a of the core insert 250.

It will be appreciated by those skilled in the art that this, end region of the core insert 250 is exposed to the highest temperatures, since molten plastic introduced into the cavity impinges directly on it during the molding process. As such, the reduction in flow area and directed flow toward this region of the core insert 250, which are provided by the core cooling tube 1270 according to this example, are particularly beneficial.

The coolant diverter 1260 is a continuation of the first tubular segment 1271, with a gradual, curved tubular transition portion 1263 between the axial bore 1261 and the radial bore 1262. The coolant diverter 1260 also includes three spacer fins 1266, which center it within the cooling channel seat 215 of the core plate 210. The radial bore 1262 and curved transition joining it to the axial bore 1261 are formed by the tubular transition portion 1263, which has a substantially constant thickness, thereby maximizing the flow area around the coolant diverter 1260, as compared with the shallow recess 263 of the coolant diverter 260 shown in FIGs. 6 to 8. This alleviates the flow restriction created by the recess 263, thereby reducing the pressure drop as the cooling fluid travels out of the core insert 250 back into the network of cooling channels 214a, 214b

CLAIMS

1. A core plate assembly (200) for incorporation into a preform mold (100), the assembly comprising a core plate (210) and a plurality of preform core inserts (250, 1250) mounted to the core plate (210) by fastening means (218, 255, 1255), wherein the fastening means (218, 255, 1255) is operable, from a rear side of the core plate (210) and/or without access to a front side of the core plate (210), to secure the preform core inserts (250, 1250) to a fixed condition in which the preform core inserts (250, 1250) are immovable relative to the core plate (210).

2. A core plate assembly (200) according to claim 1, wherein the fastening means (218, 255, 1255) comprises one or more threaded holes (255, 1255) on the rear side of each preform core insert (250, 1250), which receive respective threaded fasteners (218) that extend through holes (216) in the core plate (210) and threadedly engage the threaded holes (255, 1255) of the preform core inserts (250, 1250).

3. A core plate assembly (200) according to claim 1 or claim 2, wherein each preform core insert (250) comprises a molding surface (TSS) describing part of a top sealing surface of a preform, a taper (253) extending from the molding surface (TSS) and an annular support surface (251a) extending radially from the taper (253), the taper (253) being configured to engage, in use, with cooperating tapers (355c) of a pair of split mold inserts (350) to describe a parting line therebetween with the annular support surface (251a) engaging and supporting a facing surface (355d) of the split mold inserts (350).

4. A core plate assembly (200) according to claim 3, wherein the annular support surface (251a) is substantially perpendicular to a longitudinal axis of the preform core insert (250).

5. A core plate assembly (200) according to claim 4, wherein the taper (253) comprises a male taper (253) and the annular support surface (251a) includes a conical recess for inhibiting separation of a split mold pair (350) engaged with the taper (253) and annular support surface (251a).

6. A core plate assembly (200) according to claim 5, wherein the conical recess is depressed at an angle of 20 degrees or less.

7. A core plate assembly (200) according to claim 5, wherein the conical recess is depressed at an angle of 10 degrees or less.

8. A core plate assembly (200) according claim 1 or claim 2, wherein each preform core insert

(1250) comprises a primary core insert (1250a) and a core ring (1250b), the primary core insert (1250a) including a base (1251) for mounting to the core plate (210), a molding surface (1252) for molding an internal surface of a preform and an interface portion (1251b) between the base (1251) and the molding surface (1252), the core ring (1250b) receiving the interface portion (1251b) and comprising a taper (1253) for engaging cooperating tapers (355c) of a pair of split mold inserts (350).

9. A core plate assembly (200) according to claim 8, wherein the core ring (1250b) is press-fit to the interface portion (1251b) or otherwise secured directly to the primary core insert (1250a).

10. A core plate assembly (200) according to claim 8 or claim 9, wherein each preform core insert (1250) comprises a vent passage described at least in part between the primary core insert (1250a) and the core ring (1250b).

11. A core plate assembly (200) according to any preceding claim, wherein the fastening means

(218, 255, 1255) is operable, when the assembly is incorporated in an assembled mold, to secure the preform core inserts (250, 1250) from a movable or floating condition, in which the preform core inserts (250, 1250) are able to slide relative to the core plate (210) along a sliding interface therebetween, to the fixed condition, the mounting surface (254, 1254) being at the end of each preform core insert (250, 1250) and being free of any projections, thereby to enable the preform core inserts (250, 1250) to slide relative to the core plate (210) along the sliding interface when the preform core inserts (250, 1250) are in the floating condition.

12. A preform mold (100) comprising a core plate (210), a cavity plate and a plurality of mold stacks mounted between the core and cavity plates, each mold stack comprising a core insert (250,

1250) mounted to the core plate (210) by fastening means (218, 255, 1255), a cavity insert mounted to the cavity plate and split mold inserts mounted between the core and cavity inserts, wherein the fastening means (218, 255, 1255) is operable, from a rear side of the core plate

(210) and/or without access to a front side of the core plate (210), to secure the core inserts (250, 1250) to a fixed condition in which the core inserts (250, 1250) are immovable relative to the core plate (210).

13. A preform mold (100) according to claim 12, wherein the fastening means (218, 255, 1255) comprises one or more threaded holes (255, 1255) on the rear side of each core insert (250, 1250) and corresponding threaded fasteners (218) that extend through respective holes (216) in the core plate (210) and threadedly engage the threaded holes (255, 1255) of the core inserts (250, 1250).

14. A preform mold (100) according to claim 12 or claim 13, wherein each preform core insert (250) comprises a molding surface (TSS) describing part of a top sealing surface of a preform, a taper (253) extending from the molding surface and an annular support surface (251a) extending radially from the taper (253), the taper (253) being configured to engage, in use, with cooperating tapers (355c) of a pair of split mold inserts (350) to describe a parting line therebetween with the annular support surface (251a) engaging and supporting a facing surface (355d) of the split mold inserts (350).

15. A preform mold (100) according to claim 14, wherein the annular support surface is substantially perpendicular to a longitudinal axis of the preform core insert (250).

16. A preform mold (100) according to claim 15, wherein the taper (253) comprises a male taper (253) and the annular support surface (251a) includes a conical recess for inhibiting separation of a split mold pair (350) engaged with the taper (253) and annular support surface (251a).

17. A preform mold (100) according to claim 16, wherein the conical recess is depressed at an angle of 20 degrees or less.

18. A preform mold (100) according to claim 16, wherein the conical recess is depressed at an angle of 10 degrees or less.

19. A preform mold (100) according to claim 12 or claim 13, wherein each core insert (1250) comprises a primary core insert (1250a) and a core ring (1250b), the primary core insert (1250a) including a base (1251) for mounting to the core plate (210), a molding surface (1252) for molding an internal surface of a preform and an interface portion (1251b) between the base (1251) and the molding surface (1252), the core ring (1250b) receiving the interface portion (1251b) and comprising a taper (1253) for engaging cooperating tapers (355c) of a pair of split mold inserts (350).

20. A preform mold (100) according to claim 19, wherein the core ring (1250b) is press-fit to the interface portion (1251b) or otherwise secured directly to the primary core insert (1250a).

21. A preform mold (100) according to claim 19 or claim 20, wherein each core insert (1250) comprises a vent passage described at least in part between the primary core insert (1250a) and the core ring (1250b).

22. A preform mold (100) according to any one of claims 12 to 21, wherein the fastening means (218, 255, 1255) is operable, when the mold is assembled, to secure the preform core inserts

(250, 1250) from a movable or floating condition, in which the preform core inserts (250, 1250) are able to slide relative to the core plate (210) along a sliding interface therebetween, to the fixed condition, the mounting surface (254, 1254) being at the end of each preform core insert (250, 1250) and being free of any projections, thereby to enable the preform core inserts (250, 1250) to slide relative to the core plate (210) along the sliding interface when the preform core inserts (250, 1250) are in the floating condition.

23. A preform core insert (250, 1250) comprising a base (251, 1251) with a first end comprising a mounting surface (254, 1254) and a second end comprising a molding surface (252a, 1252) for molding an internal surface of a preform, wherein the core insert (250, 1250) comprises one or more threaded holes (255, 1255) in the mounting surface (254, 1254) for threadedly engaging a fastener (218) which is operable, from a rear side of the core plate (210) and/or without access to a front side of the core plate (210), to secure the core insert (250, 1250) to a fixed condition in which the core insert (250, 1250) is immovable relative to the core plate (210).

24. A preform core insert (250) according to claim 23 comprising a molding surface (TSS) describing part of a top sealing surface of a preform, a taper (253) extending from the molding surface (TSS) and an annular support surface (251a) extending radially from the taper (253), the taper (253) being configured to engage, in use, with cooperating tapers (355c) of a pair of split mold inserts (350) to describe a parting line therebetween with the annular support surface (251a) engaging and supporting a facing surface (355d) of the split mold inserts (350).

25. A preform core insert (250) according to claim 24, wherein the annular support surface (251a) is substantially perpendicular to a longitudinal axis of the preform core insert (250).

26. A preform core insert (250) according to claim 25, wherein the taper (253) comprises a male taper (253) and the annular support surface (251a) includes a conical recess for inhibiting separation of a split mold pair (350) engaged with the taper (253) and annular support surface

(251a).

27. A preform core insert (250) according to claim 26, wherein the conical recess is depressed at an angle of 20 degrees or less.

28. A preform core insert (250) according to claim 26, wherein the conical recess is depressed at an angle of 10 degrees or less.

29. A preform core insert (1250) according to claim 23 comprising a primary core insert (1250a) and a core ring (1250b), the primary core insert (1250a) including the base (1251), the molding surface (1252) and an interface portion (125 lb) between the base (1251) and the molding surface (1252), the core ring (1250b) receiving the interface portion (1251b) and comprising a taper (1253) for engaging cooperating tapers (355c) of a pair of split mold inserts (350).

30. A preform core insert (1250) according to claim 29, wherein the core ring (1250b) is press-fit to the interface portion (1251b) or otherwise secured directly to the primary core insert (1250a).

31. A preform core insert (1250) according to claim 29 or claim 30 comprising a vent passage described at least in part between the primary core insert (1250a) and the core ring (1250b).

32. A preform core insert (1250) according to any one of claims 23 to 31 comprising a spigot extending from the mounting surface (1254) for receipt within a seat of a core plate (210).

33. A preform core ring (1250b) for use in a preform core insert (1250) according to any one of claims 29 to 32, the core ring (1250b) comprising a flange portion (125 ), a male taper (1253) projecting from the flange portion (125 ) and an internal interface surface (1251b’) for engaging, in use, the interface portion (1251b) of a primary core insert (1250a).

34. A preform core ring (1250b) according to claim 33, wherein at least part of a vent passage is described by the internal interface surface.

35. A preform core ring (1250b) according to claim 34, wherein the internal interface surface comprises a recess describing at least part of the vent passage.

36. A preform core ring (1250b) according to any one of claims 33 to 35, wherein at least part of a vent passage is described by the male taper.

37. A preform core ring (1250b) according to claim 36, wherein the male taper comprises a recess describing at least part of the vent passage.

38. A preform core ring (1250b) according to any one of claims 33 to 37 comprising a vent passage extending from the internal interface surface to the male taper.

39. A preform core insert (250) comprising a molding surface (TSS) describing part of a top sealing surface of a preform, a taper (253) extending from the molding surface (TSS) and an annular support surface (251a) extending radially from the taper (253), the taper (253) being configured to engage, in use, with cooperating tapers (355c) of a pair of split mold inserts (350) to describe a parting line therebetween with the annular support surface (251a) engaging and supporting a facing surface (355d) of the split mold inserts (350).

40. A preform core insert (250) according to claim 39, wherein the annular support surface (251a) is substantially perpendicular to a longitudinal axis of the preform core insert (250).

41. A preform core insert (250) according to claim 39 or claim 40, wherein the taper (253) comprises a male taper (253) and the annular support surface (251a) includes a conical recess for inhibiting separation of a split mold pair (350) engaged with the taper (253) and annular support surface (251a).

42. A preform core insert (250) according to claim 41, wherein the conical recess is depressed at an angle of 20 degrees or less.

43. A preform core insert (250) according to claim 41, wherein the conical recess is depressed at an angle of 10 degrees or less.

44. A method of securing a plurality of core inserts to a core plate (210) of a preform mold (100), the method comprising:

mounting a plurality of core inserts (250, 1250) to the core plate (210); and

securing the core inserts (250, 1250) into a fixed condition from a rear side of the core plate (210) and/or without access to a front side of the core plate (210).

45. A method according to claim 44, wherein the core inserts (250, 1250) are mounted to a front side of the core plate (210) and securing the core inserts (250, 1250) to the fixed condition is performed from a rear side of the core plate (210).

46. A method of aligning a plurality of core inserts (250, 1250) mounted to a core plate (210) of a preform mold (100), the method comprising:

mounting a plurality of core inserts (250, 1250) to the core plate (210) in a floating condition, in which the core inserts (250, 1250) are able to slide relative to the core plate (210) along a sliding interface therebetween;

aligning the core inserts (250, 1250) relative to other mold inserts (350, 430); and securing the core inserts (250, 1250) into a fixed, aligned condition, in which the core inserts (250, 1250) are immovable relative to the core plate (210) and aligned with the other mold inserts (350, 430).

47. A method according to claim 46, wherein aligning the core inserts (250, 1250) relative to the other mold inserts (350, 430) comprises bringing together and securing the core inserts (250, 1250) and the other mold inserts (350, 430) into a closed configuration and securing the core inserts (250, 1250) to the fixed, aligned condition is performed with the mold inserts (250, 1250, 350, 430) in the closed configuration.