GB2617175A

GB2617175A - Mould assembly and method

Info

Publication number: GB2617175A
Application number: GB2204686.6A
Authority: GB
Inventors: George Prozesky Daniel; Richard Ashcroft Theo
Original assignee: Pulpex Ltd
Current assignee: Pulpex Ltd
Priority date: 2022-03-31
Filing date: 2022-03-31
Publication date: 2023-10-04
Also published as: WO2023187363A1; GB202204686D0

Abstract

A moulding method comprises: placing a receptacle 22 into a cavity of a first part 45 of a mould (41); operating a retaining mechanism (42, fig. 2) to retain the receptacle within the cavity; and placing a second part of the mould around a portion of the receptacle when retained. Operating the retaining mechanism may comprise inserting a retaining member 43 into the receptacle. A mould assembly 40 comprises: a mould (41) for receiving a receptacle, the mould comprising a first part 45 and at least a second part 47 moveable relative to the first part; and a retaining mechanism 42. The first part comprises a cavity 49 for receiving part of the receptacle; the second part is moveable to surround a portion of the receptacle; and the retaining mechanism is operable to retain the receptacle within the cavity of the first part during movement of the second part. The process can be used to make receptacles such as bottles from paper pulp.

Description

MOULD ASSEMBLY AND METHOD

TECHNICAL FIELD

The present invention relates to a method and an assembly for placing a receptacle into a mould

BACKGROUND

A receptacle, such as a bottle, may be placed into a mould in readiness for a forming operation. In examples, the receptacle may be susceptible to damage when placing the receptacle in the mould. For example, the receptable may be relatively soft and therefore care may be required when placing the receptacle into the mould.

SUNIMARY

The present invention provides a method comprising placing a receptacle into a cavity of a first part of a mould, operating a retaining mechanism to retain the receptacle within the cavity, and placing a second part of the mould around a portion of the receptacle when retained.

By retaining the receptacle within the cavity, the receptacle is retained in a pre-determined position in the first part of the mould and, moreover, the receptacle is prevented from falling out of the first part of the mould prior to placing the second part of the mould around the portion of the receptacle. Additionally, potential damage to the receptacle, which might otherwise arise when placing the second part around the portion of the receptacle, may be avoided. For example, should the receptacle move significantly within the cavity, the receptacle may be pinched between the first and second parts. By retaining the receptacle within the cavity, such damage may be avoided. Optionally, the receptabl e is a bottle.

Operating a retaining mechanism may comprise inserting a retaining member into the receptacle. Inserting a retaining member into the receptacle may provide a relatively inexpensive and robust mechanism for retaining the receptacle within the cavity.

The method may comprise applying a holding force to an exposed portion of the receptacle to hold the receptacle within the cavity during the inserting of the retaining member and removing the holding force during or after the inserting of the retaining member. By applying the holding force, the receptacle may be prevented from moving during insertion of the retaining member. As a result, potential damage to the receptacle by the retaining member due to misalignment may be avoided. By subsequently removing the holding force, the second part may be placed around the portion of the retained receptacle unimpeded.

The receptacle may be sized such that, in the absence of the holding force, the receptacle is free to move within the cavity. The receptacle is therefore smaller than the cavity. Forming operations may then be applied to the receptacle that cause the receptacle to expand within the mould.

Inserting the retaining member into the receptacle may comprise inserting the retaining member into a neck or opening of the receptacle. The mould assembly therefore makes use of an opening in the receptacle to retain the receptacle. As a result, the receptacle may be retained more securely within the cavity of the first part of the mould.

Inserting the retaining member into the receptacle may comprise moving the retaining member along a curved path. Moving along a curved path may enable the same retaining member to be used with a greater range of receptacle shapes and sizes.

Optionally, the method may comprise removing the retaining member from the receptacle along a curved path.

The retaining member may have rounded or chamfered edges. As a result, potential damage to the receptacle may be avoided that might otherwise arise should the retaining member contact the receptacle. For example, if the retaining member were to have sharp edges, the edges may score, mark or otherwise damage the receptacle upon contact. Optionally, each edge may have a radius of curvature of at least 0.9 mm. As a result, damage to the receptacle, such as scoring or marking of the receptacle by the retaining member, may be reduced.

The retaining member may comprise an arcuate surface that subtends a central angle of no less than 15 degrees or no more than 180 degrees. By ensuring that the arcuate surface subtends a central angle no less than 15 degrees, a force exerted by the retaining member on the receptacle, when retained within the cavity, may be distributed over a larger area. Thereby, potential deformation in the receptacle by the retaining member may be reduced. Additionally or alternatively, by ensuring that the arcuate surface subtends a central angle no more than 180 degrees, the retaining member may be inserted into the receptacle with less precise alignment of the receptacle and the retaining member. In contrast, if the arcuate surface were to subtend a central angle of greater than 180 degrees, more precise alignment and control of the retaining member and the receptacle may be required to ensure that the retaining member does not contact and potentially damage the receptacle during insertion. Optionally, the retaining member may be inserted into the receptacle such that the arcuate surface faces the first part. As a result, should the receptacle move in a direction away from the first part, the retaining member contacts the receptacle along the arcuate surface. Thereby, the retaining member is less likely to mark, deform or otherwise damage the receptacle The second part of the mould may comprise a cavity for receiving part of the receptacle. Placing the second part of the mould around the portion of the receptacle may cause the receptacle to be retained within a mould cavity comprising the cavity of the first part of the mould and the cavity of the second part of the mould. The mould may comprise an opening to the mould cavity, the opening having a central axis, and the retaining member, when inserted into the receptacle through the opening, may be offset from the central axis of the opening in a direction toward the first part of the mould. As a result, should the receptacle move and contact the retaining member, the amount of movement or travel of the receptacle may be reduced. Thereby, the force exerted on the receptacle by the retaining member may be reduced, and thus the retaining member is less likely to damage the receptacle.

The method may comprise terminating operation of the retaining mechanism and applying a forming operation to the receptacle within the mould. By terminating operation of the retaining mechanism, subsequent operations (such as a forming operation) may be performed on the receptacle unimpeded by the retaining mechanism. Where the retaining mechanism comprises a retaining member that is inserted into the receptacle, terminating operation of the retaining mechanism may comprise removing the retaining member from the receptacle. Equipment for performing the forming operation may then be inserted into the same opening of the receptacle.

The forming operation may comprise thermoforming Thermoforming may improve the mechanical properties of the receptacle, such as stiffness, as well as the surface finish of the receptacle.

The forming operating may comprise inserting an expandable member into the receptacle and expanding the expandable member within the receptacle By expanding (such as inflating) the expandable member within the receptacle, the expandable member may apply a force to the inside of the receptacle to press the receptacle into the mould and thereby compress the walls of the receptacle and, in examples, increase the rigidity of the receptacle.

The receptacle may be at least partially formed of paper pulp. The choice of paper is ecologically more friendly than plastic. However, in being formed of paper, the receptacle is particular susceptible to damage, such as pinching, when placing the parts of mould around the receptacle. By retaining the receptacle in the cavity of the first part of the mould such damage may be avoided.

The second part of the mould may comprise a cavity for receiving part of the receptacle. Placing the second part of the mould around the portion of the receptacle may cause the receptacle to be retained within a mould cavity comprising the cavity of the first part of the mould and the cavity of the second part of the mould and a difference in maximum diameters of the mould cavity and the receptacle may be no greater than 5 mm. As a result, damage caused to the receptacle during forming due to excessive increases in diameter may be reduced. Specifically, as the diameter of the mould cavity relative to the diameter of the receptacle increases, the receptacle experiences a larger relative change in diameter during the forming operation. If the relative diameter of the mould cavity is excessively large (say larger than 5 mm), the receptacle may tear or develop weak portions when the forming operation is applied. The difference in maximum diameters of the mould cavity and the receptacle may be no less than 0.1 mm. The mould cavity is therefore larger than the receptacle, which may have one or more benefits. For example, a forming operation may be applied to the receptacle that causes the receptacle to expand within the mould. Additionally, receptacles received within the mould cavity may be of slightly different diameters due to manufacturing tolerances. By having a mould cavity that is larger than the nominal diameter of the receptacle, the mould cavity is able to accommodate this variability in diameter of receptacle. As the diameter of the mould cavity relative to the diameter of the receptacle increases, the receptacle may be placed within the cavity using less accurate control. A good balance between the competing needs of ease of insertion and reduced damage during forming may be achieved by ensuring that a difference between the maximum diameters of the mould cavity and the receptacle is no less than 0.1 mm and no greater than 5 mm, or no less than 0.75 mm and no greater than 5 mm.

The present invention also provides a mould assembly comprising a mould for receiving a receptacle, the mould comprising a first part and at least a second part moveable relative to the first part, and a retaining mechanism, wherein the first part comprises a cavity for receiving part of the receptacle, the second part is moveable to surround a portion of the receptacle, and the retaining mechanism is operable to retain the receptacle within the cavity of the first part during movement of the second part. By retaining the receptacle within the cavity, the receptacle is prevented from falling out of the first part of the mould prior to the second part being moved to surround the receptacle. Additionally, potential damage to the receptacle, which might otherwise arise when moving the second part, may be avoided. For example, should the receptacle move significantly within the cavity, the receptacle may be pinched between the first and second parts. By retaining the receptacle within the cavity, such damage may be avoided.

Typically, the second part of the mould is moveable to surround a portion of the receptacle which is not surrounded by the first mould. For example, the second part of the mould is moveable to surround the entire portion of the receptacle which is not surrounded by the first part of the mould, excluding an opening of the receptacle. Alternatively, the second part of the mould is moveable to surround part of the portion of the receptacle which is not surrounded by the first part of the mould, and one or more further parts of the mould are moveable to surround the rest of the receptacle, excluding the opening of the receptacle.

The retaining mechanism may comprise a retaining member. The retaining member may be moveable relative to the first part between a first position and a second position. The retaining member may be located outside of the cavity in the first position and the retaining member may extend into the cavity in the second position such that, when the part of the receptable is received within the cavity, the retaining member may extend into the receptacle to retain the receptacle in the cavity. Inserting a retaining member into the receptacle may provide a relatively inexpensive and robust mechanism for retaining the receptacle within the cavity. After the second part of the mould is placed around the portion of the receptacle, the retaining member may be returned to the first position and a forming operation may be performed on the receptacle.

The mould assembly may be configured such that, in the second position, the retaining member extends into a neck of the cavity. During use, a neck of the receptacle may be located within the neck of the cavity. Therefore, the mould assembly may make use of an opening in the receptacle to retain the receptacle. As a result, the receptacle may be retained more securely within the cavity of the first part of the mould.

The retaining member may comprise an arcuate surface that subtends a central angle of no less than 15 degrees or no more than 180 degrees. By ensuring that the arcuate surface subtends a central angle of no less than 15 degrees, a force exerted by the retaining member on the receptacle, when retained within the cavity, may be distributed over a larger area. Thereby, potential deformation in the receptacle by the retaining member may be reduced. Additionally or alternatively, by ensuring that the arcuate surface subtends a central angle of no more than 180 degrees, the retaining member may be inserted into the receptacle with less precise alignment of the receptacle and the retaining member. In contrast, if the arcuate surface were to subtend a central angle of greater than 180 degrees, more precise alignment and control of the retaining member and the receptacle may be required to ensure that the retaining member does not contact and potentially damage the receptacle, The retaining member may be moveable along a curved path between the first position and the second position. Moving along a curved path may enable the same retaining member to be used with a greater range of receptacle shapes and sizes.

The mould assembly may be configured such that, in the second position, the arcuate surface faces the first part As a result, should the receptacle move in a direction away from the first part, the retaining member contacts the receptacle along the arcuate surface. Thereby, the retaining member is less likely to mark, deform or otherwise damage the receptacle.

The second part of the mould may comprise a cavity for receiving part of the receptacle. When the second part is moved to surround a portion of the receptacle (e.g. the entire portion of the receptacle which is not surrounded by the first part of the mould, excluding the opening of the receptacle), the mould may comprise a mould cavity comprising the cavity of the first part and the cavity of the second part. The mould may comprise an opening to the mould cavity, the opening having a central axis, and the retaining member, when in the second position, may be offset from the central axis in a direction toward the first part of the mould. As a result, should the receptacle move and contact the retaining member, the amount of movement or travel of the receptacle may be reduced. Thereby, the force exerted on the receptacle by the retaining member may be reduced, and thus the retaining member is less likely to damage the receptacle.

The retaining member may have rounded or chamfered edges. As a result, potential damage to the receptacle may be avoided that might otherwise arise should the retaining member contact the receptacle. For example, if the retaining member were to have sharp edges, the edges may score, mark or otherwise damage the receptacle upon contact. Optionally, each edge may have a radius of curvature of at least 0.9 mm.

The retaining member may comprise an elongated finger that extends into the cavity in the second position. As a result, a range of receptacle sizes and shapes (e.g., short and wide, or tall and thin) may be retained by the same retaining member.

The mould assembly may comprise a controller configured to cause movement of the retaining member from the first position to the second position, and then relative movement of the first part and the second part to place the second part around the portion of the receptable. Thereby, an amount of operator input required to operate the mould assembly may be reduced compared to, for example, a mould assembly where the operator manually moves the retaining member and parts of the mould. Additionally, this may result in reduced process times which may increase the throughput of a process employing the mould assembly.

The mould assembly may comprise an expandable member operable to be inserted into the receptacle and expanded to apply a forming operation to the receptacle. By expanding (such as inflating) the expandable member within the receptacle, the expandable member may apply a force to the inside of the receptacle to press the receptacle into the mould and thereby compress the walls of the receptacle and, in examples, increase the rigidity of the receptacle. Where the retaining mechanism comprises a retaining member, the retaining member and the expandable member may be inserted into the same opening of the receptacle. For example, the retaining member may be moved from the second position to the first position to remove the retaining member from the receptacle. The expandable member may then be inserted into the receptacle unimpeded by the retaining member.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure I shows an example of a process for producing a receptacle at least partially moulded from a fibre suspension; Figure 2 shows a perspective view of a mould assembly; Figure 3 shows, by way of simplified sections, different stages in the placement of a receptacle within the mould assembly, wherein (a) the receptacle is received within a cavity of a first part of the mould assembly, (b) a retaining member of the mould assembly is inserted into the receptacle; (c) a second part of the mould assembly is placed around the receptacle; and (d) the retaining member is removed from the receptacle.

Figure 4 shows a sectioned view of an alternative retaining member of the mould assembly taken through a plane perpendicular to a central axis of an opening of the receptacle; Figure 5 shows an example method which may be implementation using the 5 mould assembly and Figure 6 shows an example method for applying a forming operation to the receptacle.

DETAILED DESCRIPTION

Figure I shows a process for making receptacles, such as bottles, from paper pulp (i.e., which can form the basis of an example fibre suspension). The process is merely exemplary and is provided to give context to examples of the present invention. Broadly speaking, the exemplary process comprises providing a fibre suspension, introducing the fibre suspension into a mould cavity of a porous first mould and using the porous first mould to expel a liquid (such as water) from the fibre suspension to produce a wet precursor or embryo (which may itself be considered a moulded receptacle), further moulding the wet precursor in a mould to produce a further-moulded receptacle, coating the further-moulded receptacle to produce a coated moulded receptacle, drying the coated moulded receptacle to produce a dried receptacle, and applying a closure to the dried receptacle. As will be apparent at least from the following description, modifications may be made to the exemplary process to provide variants thereof in which other examples of the present invention may be embodied.

In this example, providing the fibre suspension comprises preparing the fibre suspension from ingredients thereof More specifically, the preparing comprises providing pulp fibres, such as paper pulp fibres, and mixing the pulp fibres with a liquid to provide hydrated pulp fibres. In this example, the pulp fibres are provided in sheet form from a supplier and the liquid comprises water and one or more additives. In this example, the liquid is mixed with the pulp fibres to provide hydrated pulp fibres having a solid fibres content of lwt% to 5wt% (by dry mass of fibres). In examples, the one or I0 more additives includes a shorting agent, such as alkyl ketene di mer (AK D). The hydrated pulp fibres typically comprise AKD in an amount of 0.4wt% with respect to the total dry mass of the solid fibres in the hydrated pulp fibres. In some examples, one or more additives are present in the liquid at the point of mixing the pulp fibres with the liquid In some examples, one or more additives are included in the hydrated pulp fibres after mixing the pulp fibres with the liquid (e.g. the pulp fibres are hydrated for a period of time, such as from 2 to 16 hours, and then one or more additives are supplied to the hydrated pulp fibres). The hydrated pulp fibres are passed between plates of a valley beater 11 or refiner that are in motion relative to each other. This fibrillates some or all of the fibres, meaning that cell walls of those fibres are caused to become partially delaminated so that wetted surfaces of those fibres comprise protruding hairs or fibrillations. These fibrillations will help to increase a strength of bonds between the fibres in the dried end product. In other examples, the valley beater 11 or refiner may be omitted.

The resultant processed pulp is stored in a vat 12 in a relatively concentrated form (e.g. a solid fibres content of lwt% to 5wt%) to reduce a required storage space. At an appropriate time, the processed pulp is transferred to a mixing station 13 at which the processed pulp is diluted in further water and, optionally, mixed with one or more additives (as well as, or in place of, the one or more additives provided with the hydrated pulp fibres) to provide the fibre suspension ready for moulding. In this example, the solid fibres account for 0.7wt% of the resultant fibre suspension (by dry weight of fibres), but in other examples the proportion of solid fibres in the fibre suspension may be different, such as another value in the range of 0.5wt% to 5wt%, or 0.1wt% to lwt%, of the fibre suspension (by dry weight of fibres). In some examples, the one or more additives mixed with the processed pulp and water includes a dewatering agent, such as modified and/or unmodified polyethylene imine (PEI), e.g. modified PEI sold under the trade name Polymin® SK. In some examples, the one or more additives are mixed with the water, and the water and one or more additives subsequently mixed with the processed pulp; in other examples, the processed pulp and water are mixed, and the one or more additives subsequently mixed with the processed pulp and water. The fibre suspension typically comprises Polymin® SK in an amount of 0.3wt% with respect to the total dry mass of the

II

solid fibres. Mixing of the fibre suspension at the mixing station 13 helps to homogenise the fibre suspension In other examples, the processed pulp or the fibre suspension may be provided in other ways, such as being supplied ready-made.

In this example, the porous first mould 15 comprises two half-moulds that are movable towards and away from each other, in this case using a hydraulic ram. In this example, each of the half-moulds is a monolithic or unitary tool formed by additive manufacturing (e.g., 3D-printing) that defines a mould profile, and, when the half-moulds are brought into contact with each other, their respective mould profiles cooperate to define the mould cavity in which the wet precursor or moulded receptacle is to be formed.

Each half-mould may itself define a smaller moulding cavity and, when brought into cooperation with a second half-mould, the smaller moulding cavities may combine to provide the overall mould cavity. The two half-moulds may themselves be considered "splits" or "moulds" and the overall porous first mould 15 may be considered a "split-mould" or, again, a "mould". In other examples, the porous first mould 15 may comprise more than two splits, such as three, four or six splits, that cooperate to define the moulding cavity.

In Figure 1, the fibre suspension (also known as slurry) is top-filled into the porous mould 15, in contrast to moulding processes that dip a mould in slurry. The fibre suspension is drawn under vacuum via a line 16 and into the porous mould 15, with excess suspending liquid being drawn through the porous mould 15 under vacuum via a line 18 into a tank 17. Shot mass may be controlled by measuring (e.g., weighing) the amount of liquid drawn into the tank 17. A weight scale platform supporting the tank 17 is visible in Figure 1. Once a required amount (e.g. a predetermined volume, such as 10 litres, or a predetermined mass, such as 10 kilograms) of liquid has been collected in the tank 17, suction of the suspending liquid through the porous mould 15 is stopped and the porous mould 15 is opened to ambient air. In this example, the suspending liquid drawn with the fibre suspension in line 16 is water, or predominantly water (as additives may also be present). The liquid drawn under vacuum via the line 18 and into the tank 17 is substantially free of fibres, since these are left behind against the walls of the porous mould 15 to form an embryo of the moulded receptacle.

In one form, in order to remove further suspending liquid (e.g., water) from the embryo and form or consolidate the three-dimensional shape of the receptacle, an impermeable inflation element 19, e.g., a collapsible bladder, is inserted into the porous mould 15 and expanded to act as an internal high-pressure core structure for the porous mould 15. This process strengthens the wet embryo so that it can be handled, and displaces water from in-between the fibres, thereby increasing the efficiency of a subsequent drying process. The inflation element 19 is actuated and regulated using a hydraulic pump 20. The pump 20 has a cylinder that displaces a fluid in a line 21 into the inflation element 19 to expand the inflation element 19 radially and into conformity with the mould cavity. Fluid within the line 21 is preferably non-compressible, such as water.

Water also has the advantage over other non-compressible liquids that any leaking or bursting of the bladder 19 will not introduce a new substance to the system (since the suspending liquid is already water or predominantly water).

Demoulding occurs when the porous mould 15 opens for removal of the self-supporting moulded receptacle 22. Mould cleaning 23 is preferably performed subsequently, to remove small fibres and maintain a porosity of the porous mould 15. In this example, a radially-filing high-pressure jet is inserted into the mould cavity while the mould 15 is open. This dislodges fibres from the wall of the mould cavity. Alternatively, or in addition, water from the tank 17 is pressurised through the back of the porous mould 15 to dislodge entrapped fibres. Water is drained for recycling back to an upstream part of the system. It is noteworthy that cleaning is important for conditioning the porous mould 15 for re-use. The porous mould 15 may appear visibly clean after removal of the receptacle, but its performance could be compromised without cleaning.

According to Figure 1, the formed but unfinished receptacle 22 is subsequently transported to a second moulding station where, in a, e.g., aluminium, mould 25, pressure and heat are applied for thermoforming a desired neck and surface finish, optionally including embossed and/or debossed surface features. After two halves of the mould 25 have closed around the receptacle 22, a pressuriser is engaged. For example, a bladder 26 (e.g., a thermoforming bladder 26) is inserted into the receptacle 22. The bladder 26 is inflated via a line 27 by a pump 28 to supply pressurised fluid, e.g., air, water or oil.

Optionally, during supply, the pressurised fluid is heated with e.g. a heater or, alternatively, is cooled with e.g. a heat exchanger. An external mould block 24 of the mould 25, and/or the mould 25 itself, may also, or alternatively, be heated. A state of the moulded receptacle 22, after thermoforming, is considerably more rigid, with more compressed side walls, compared to the state at demoulding from the porous mould 15.

A drying stage 29 (e.g., a microwave drying process or other drying process) is performed downstream of the thermoforming, as shown. In one example, the drying stage 29 is performed before thermoforming. However, moulding in the mould 25 requires some water content to assist with bonding during the compression process. Figure 1 illustrates a further drying stage 30, after the drying stage 29, which may utilise hot air circulated onto the moulded receptacle 22, e.g., in a "hot box". In some examples, microwave or other drying processes may be performed at plural stages of the overall manufacturing process.

The moulded receptacle 22 is then subjected to a coating stage during which, in this example, a spray lance 31 is inserted into the moulded receptacle 22 and applies one or more surface coatings to internal walls of the moulded receptacle 22. In another example, the moulded receptacle 22 is instead filled with a liquid that coats the internal walls of the moulded receptacle 22. In practice, such coatings provide a protective layer to prevent egress of contents into the receptacle wall which may permeate and/or weaken it. Coatings will be selected dependent on the intended contents of receptacle 22, e.g., a beverage, detergent, pharmaceutical product etc. In some examples, the further drying stage 30 is performed after the coating stage (or both before and after the coating stage) In this example, the moulded receptacle 22 is then subjected to a curing process 34, which can be configured or optimised dependent on the coating, e.g., drying for twenty-four hours at ambient conditions or by a flash diving method. In some examples, e.g. where the further drying stage 30 occurs after the coating stage, the curing process 34 may be omitted.

At an appropriate stage of production (e.g., during thermoforming, or before or after coating) a closure or mouth forming process may be performed on the moulded receptacle 22. For example, as shown in Figure 1, a neck fitment 35 may be affixed. In some examples, an exterior coating is applied to the moulded receptacle 22, as shown in the further coating stage 32. In one example, the moulded receptacle 22 is dipped into a liquid that coats its outer surface, as shown in Figure 1. One or more further drying or curing processes may then be performed. For example, the moulded receptacle 22 may be allowed to dry in warm air. The moulded receptacle 22 may therefore be fully formed and ready to accept contents therein.

Figure 2 shows a mould assembly 40 which may be used to thermoform the formed but unfinished receptacle 22 discussed above. The mould assembly 40 comprises a mould 41 and a retaining mechanism 42.

The mould 41 comprises a first part 45 and a second part 47. In other examples, the mould 41 may comprise more than two parts. The two parts 45,47 are separable so as to open the mould 41. Each part 45,47 comprises a cavity 49. When the two parts 45,47 are brought together to close the mould 41, a mould cavity 51 (shown in Figures 3(c) and 3(d)) is created within the mould 41 that comprises the cavities of the first part 45 and the second part 47. In this particular example, the mould cavity 51 has the shape of a bottle and comprises a main body portion 53 and a neck portion 55. The neck portion 55 has a smaller diameter than the body portion 53 and extends to the top of the mould 41. The mould 41 comprises an opening 57 to the mould cavity 51. As discussed in more detail below, by having an opening 57, the retaining mechanism 42 may extend into the mould 41 to retain a receptacle 22.

The retaining mechanism 42 comprises a retaining member 43 and an actuator (not shown).

The retaining member 43 comprises an elongated finger. In this example, the retaining member 43 has a dog-leg shape, the benefits of which are described below. In other examples, the retaining member may be curved or straight. The retaining member 43 is moveable relative to the first part 45 of the mould 41 between a first position and a second position. In the first position, the retaining member 43 is located outside of the mould cavity 51. The retaining member 43 is shown in the first position in Figure 2. In the second position, the retaining member 43 extends into the mould cavity 51. In this example, the retaining member 43 is moveable along a curved path 59 (shown in Figures 1_5 3(b) and 3(d)) between the first position and the second position, the benefits of which are described below. In other examples, the retaining member 43 may be moveable between the first position and the second position along a linear path.

The actuator is operable to move the retaining member 43 between the first position and the second position. In this example, the actuator is an electric motor that is coupled to the retaining member 43 by gearing and/or linkages (not shown) such that the torque generated by the electric motor causes the retaining member to move along a desired path between the first and second positions. In other examples, the actuator may be omitted and the retaining member 43 may be moved manually by an operator.

Use of the mould assembly 40, and in particular the placement of a receptacle 22 within the mould 41, will now be provided by way of Figure 3. The two parts 45,47 of the mould 41 are separated (for example manually by an operator or using a hydraulic ram) to open the mould 41. At this stage, the retaining member 43 is located in the first position. A receptacle 22 is then placed into the cavity 49 of the first part 45 of the mould 41, as shown in Figure 3(a). After placing the receptacle 22 into the cavity 49, a holding force 63 is applied to an exposed portion of the receptable 22 (e.g., the exposed side of the receptacle) to prevent the receptacle 22 from moving significantly within the cavity 49. The holding force 63 is applied to the exposed portion of the receptacle 22 so as to provide secure retainment of the receptacle 22 within the cavity 49. In this example, the receptable 22 is placed into the cavity 49 by an operator, and the holding force 63 is applied by a hand of the operator. In other examples, the receptable 22 may be placed into the cavity and the holding force 63 may be applied by other means, such as a servo arm under the control of a controller.

Turning now to Figure 3(b), with the holding force 63 in place, the retaining member 43 is inserted into the receptacle 22 by moving the retaining member 43 from the first position to the second position. In this example, the receptacle 22 is a bottle and comprises a neck 61 with an opening 62, and a main body 64. The retaining member 43 is inserted into the opening 62 of the neck 61 such that the retaining member 43 extends into the receptacle 22 to retain the receptacle 22 within the cavity 49. In other examples, the receptacle may have other shapes which do not comprise a neck. In these examples the opening is located elsewhere, for example in a wall of the receptacle, and the retaining member 43 is inserted into the opening In this example, the retaining member 43 moves along a curved path 59 between the first and second positions. This may be beneficial as it is envisaged that the mould 41 may be changed to enable a range of receptacles with different shapes and sizes to be manufactured. By moving along a curved path, the retaining member may move over the first part 45 before moving down into the receptacle 22. This may enable the same retaining member 43 to be used with a range of different moulds and therefore a greater range of receptacle shapes and sizes.

As described previously, when in the second position, the retaining member 43 retains the receptacle 22 within the cavity 49. Therefore, after or during movement of the retaining member 43 to the second position, the holding force 63 is no longer required and is removed. The receptacle 22 is then retained within the cavity 49 by the retaining member 43. The retaining member 43 prevents the receptacle 22 from moving significantly within the cavity 49. However, some movement of the receptacle 22 within the cavity 49 is still possible owing to the retaining member 43 having a width that is smaller than the width of the opening 62. As discussed previously, the holding force is applied to the exposed portion of the receptacle 22. By removing the holding force 63, the mould 41 may be closed unimpeded. For example, in examples where the holding force 63 is applied by the hand of the operator, the hand of the operator may be removed.

The mould 41 is then closed, as shown in Figure 3(c) by placing the second part 47 of the mould 41 around the retained receptacle 22. For example, the mould may be closed manually by the operator or using a hydraulic ram Turning now to Figure 3(d), with the mould 41 now closed, the retaining member 43 is no longer required to retain the receptacle 22 and is removed by moving the retaining member 43 from the second position to the first position.

With the receptacle now placed within the closed mould, a forming operation may be performed on the receptacle 22. For example, and as described previously, an expandable member (for example the bladder 26) may be inserted into the receptacle 22. The expandable member may then be inflated (for example, as described above, using the line 27 and the pump 28 to supply pressurised fluid, e.g., water or oil) and the mould 41 heated to thermoform the receptacle 22. The mould 41 may subsequently be opened by separating the two parts 45,47 of the mould 41, and the receptacle 22 removed for further processing. For example, the receptacle 22 may be dried in a drying stage 29, as described above with reference to Figure 1.

By retaining the receptacle 22 within the cavity 49 using the retaining member 43, the receptacle 22 is prevented from falling out of the first part 45 of the mould 41 prior to placing the second part 47 of the mould 41 around the receptacle 22. Additionally, potential damage to the receptacle 22, which might otherwise arise when placing the second part 47 around the receptacle 22, may be avoided. For example, should the receptacle 22 move significantly within the cavity 49, the receptacle 22 may be pinched between the first 45 and second 47 parts. By retaining the receptacle 22 within the cavity 49, such damage may be avoided. Moreover, by removing the retaining member 43, equipment for performing the forming operation (such as the expandable member) may be inserted into the same opening 62 of the receptacle 22.

The retaining member 43 has rounded edges. As a result, potential damage to the receptacle 22 may be avoided that might otherwise arise should the retaining member 43 contact the receptacle 22. For example, if the retaining member 43 were to have sharp edges, the edges may score, mark or otherwise damage the receptacle 22 upon contact. Specifically, in this example, the retaining member 43 has a rectangular cross section in a plane perpendicular to the longitudinal axis of the retaining member 43, the corners of which have a radius of curvature of 1 mm. The end of the retaining member 43 which is located within the receptacle 22 in the second position is also rounded and has a radius of curvature of 5 mm. As a result, damage to the receptacle 22, such as scoring or marking of the receptacle 22 by the retaining member 43, may be reduced. However, in other examples, the edges may have a greater or lesser radius of curvature. As the radius of curvature decreases, the edges become sharper and therefore more likely to damage the receptacle 22. Therefore, each edge may have a radius of curvature of at least 0.9 mm and thereby avoid potential damage to the receptacle 22. In other examples, the edges may be chamfered and achieve similar benefits As described above, the retaining member 43 has a dog-leg shape. Thereby, when moving along the curved path 59, the retaining member 43 is less likely to contact, and potentially damage, the neck 61 of the receptacle 22 Equally, the retaining member 43 may be curved and achieve the same benefit. However, as mentioned above, examples are envisaged where the retaining member 43 moves linearly, in these examples, the shape of the retaining member 43 may be straight along its length.

Figure 4 shows an example of a retaining member 71 having an alternative shape, the retaining member 71 being in the second position, extending through the opening 62 of the receptacle 22. h) this example, the retaining member 71 is again elongate and has a cross-sectional shape that resembles a circular segment. The retaining member 71 therefore comprises an arcuate surface 73 closed by a straight surface. When the retaining member 71 is in the second position, the arcuate surface 73 faces the first part 45.

Thereby, should the receptacle 22 move and contact the retaining member 71, the retaining member 71 is less likely to mark, deform or otherwise damage the receptacle 22. The arcuate surface 73 may conform (i.e., have the same or similar curvature) to the shape of the opening 62 of the receptacle 22. As a result, should the neck of the receptable 22 contact the retaining member 71, the force exerted by the retaining member 71 on the receptacle 22 may be distributed over a larger area and thereby deformations in the receptacle 22 may be reduced.

When in the second position, the retaining member 71 is offset from a central axis 50 of the opening 57. More particularly, the retaining member 71 is offset in a direction toward the first part 45 of the mould. As a result, should the receptacle 22 move and contact the retaining member 71, the amount of movement or travel of the receptacle 22 is reduced. Thereby, the force exerted on the receptacle 22 by the retaining member 71 is reduced, and thus the retaining member 71 is less likely to damage the receptacle 22.

In the example of Figure 4, the arcuate surface 73 subtends a central angle of 90 degrees. Equally the arcuate surface 73 may subtend other angles. As the central angle increases, the area over which the retaining member 71 contacts the receptacle 22, in the event that the receptacle 22 should move, increases. Thereby, the retaining member 71 is less likely to mark, deform or otherwise damage the receptacle 22. However, as the central angle and thus the size of the retaining member increases, more precise alignment of the retaining member 71 relative to the receptacle 22 may be required to ensure that the retaining member 71 does not contact and potentially damage the receptacle 22 during insertion. Accordingly, a good balance between these two competing needs may be achieved with an arcuate surface 73 that subtends a central angle of between 15 degrees and 180 degrees.

In this example, the diameter of the main body portion 53 of the mould cavity 51 is 1 mm larger than the diameter of the main body 64 of the receptacle 22. The mould cavity 51 is therefore larger than the receptacle 22, which may have one or more benefits.

For example, a forming operation may be applied to the receptacle 22 that causes the receptacle 22 to expand within the mould 41. Additionally, receptacles received within the mould cavity 51 may be of different diameters due to manufacturing tolerances. By having a mould cavity 51 that is larger than the nominal diameter of the receptacle 22, the mould cavity 51 is able to accommodate this variability in diameter of receptacle 22.

Also, the receptacle 22 may be placed within the cavity 49 with less accurate control. As the diameter of the mould cavity 51 relative to the diameter of the receptacle 22 increases, less accurate control over the placement of the receptacle 22 may be required to ensure that the receptacle is not damaged (e.g., pinched) between the first 45 and second parts 47 as the mould 41 is closed. However, as the diameter of the mould cavity 51 relative to the diameter of the receptacle 22 increases, the receptacle 22 experiences a larger relatively change in diameter during the forming operation. If the diameter of the mould cavity 51 is excessively large compared to the diameter of the receptacle 22 (say more than 5 mm larger), the receptacle 22 may tear or develop weak portions when the forming operation is applied. Accordingly, a good balance between the competing needs of ease of insertion and reducing damage during forming may be achieved by ensuring that a difference between the maximum diameters of the mould cavity 51 and the receptacle 22 is no greater than 5 mm, or is no less than 0.1 mm and no greater than 5 mm, or is no less than 075 mm and no greater than 5 mm The receptacle 22 is sized such that, in the absence of the holding force 63, the receptacle 22 is free to move within the cavity 49. The receptacle 22 is therefore smaller than the cavity 49 As discussed previously, forming operations may then be applied to the receptacle 22 that cause the receptacle 22 to expand within the mould 41.

In the above example, a holding force 63 is applied to the exposed portion of the receptacle 22. However, examples are envisaged where the holding force 63 need not be applied. For example, the receptacle 22 may be placed into the cavity 49 and the retaining member 43 may be inserted sufficiently quickly that that receptacle 22 does not fall out of the cavity 49. However, by applying a holding force to the exposed portion of the receptacle 22, the receptacle 22 may be prevented from moving during insertion of the retaining member 43 and thereby potential damage to the receptacle 22 by the retaining member 43 due to misalignment may be avoided.

In the above examples, the retaining mechanism comprises a retaining member that is inserted into the receptable However, in other examples, the retaining mechanism may comprise other means for retaining the receptacle within the cavity of the first part of the mould.

Figure 5 shows an example method 100 which may be implemented using the 20 mould assembly 40 described above.

The method 100 comprises placing 101 a receptacle into a cavity of a first part of a mould. For example, the unfinished receptacle 22 produced by the porous first mould 15 described above may be placed within the cavity 49. The receptacle 22 may be placed in the cavity 41 by an operator or a servo arm.

The method then comprises operating 105 a retaining mechanism to retain the receptacle within the cavity. In examples, this may comprise inserting a retaining member into the receptacle to retain the receptacle within the cavity. For example, the retaining member 43 described above may be moved from the first position to the second position.

A holding force may be applied 103 to an exposed portion of the receptacle to hold the receptacle within the cavity during operation of the retaining mechanism (e.g., during insertion of a retaining member) For example, the operator or the servo arm may hold the receptacle 22 within the cavity 49 the first part 45 of the mould 41. In other examples, the holding force may be omitted.

In examples where a holding force has been applied, the method 100 may comprise removing 107 the holding force after operation of the retaining mechanism For example, the operator or the servo arm may release the receptacle 22.

Then the method 100 comprises placing 109 a second part of the mould around a portion of the retained receptacle. For example, the second part 47 of the mould assembly 40 described above may be placed around the receptacle 22 Next, a forming operation may be applied 111 to the receptacle.

Figure 6 shows an example of a method 200 for performing a forming operation.

The method 200 comprises terminating operation 201 of the retaining mechanism. Where the retaining mechanism comprises a retaining member that is inserted into the receptacle, terminating operation 201 may comprise removing the retaining member from the receptacle. For example, the retaining member 43 may be moved from the second position to the first position.

Then the method 200 comprises inserting 203 an expandable member into the receptacle. For example, the expandable member may be inserted through the opening 62 in the receptacle 22. Next, the method 200 comprises inflating 205 the expandable member. By inflating the expandable member within the receptacle, the expandable member may apply a force to the inside of the receptacle to press the receptacle into the mould and thereby compress the walls of the receptacle. The mould may be heated such that the forming operation comprises thermoforming.

Although in the above examples the mould 41 is described as being closed arid the retaining member 43 moved by an operator. In other examples, these processes may be automated. The mould assembly 40 may therefore comprise a controller configured to operate the retaining mechanism (e.g., cause movement of the retaining member 43 from the first position to the second position) and then relative movement of the first part 45 and the second part 47 to place the second part 47 around the receptable 22. For example, the controller may control hydraulic rams for moving the first part 45 and the second part 47.

Whilst particular examples and embodiments have thus far been described, it should be understood that these are illustrative only and that various modifications may be made without departing from the scope of the invention as defined by the claims.

Claims

CLAIMS: 1. A method comprising: placing a receptacle into a cavity of a first part of a mould; operating a retaining mechanism to retain the receptacle within the cavity; and placing a second part of the mould around a portion of the receptacle when retained.
2. The method of claim 1, wherein operating the retaining mechanism comprises inserting a retaining member into the receptacle The method of claim 2, wherein the method comprises: applying a holding force to an exposed portion of the receptacle to hold the receptacle within the cavity during the inserting of the retaining member; and removing the holding force during or after the inserting of the retaining member.4. The method of claim 3, wherein the receptacle is sized such that, in the absence of the holding force, the receptacle is free to move within the cavity.5. The method of any one of claims 2 to 4, wherein inserting the retaining member into the receptacle comprises inserting the retaining member into a neck of the receptacle.6 The method of any one of claims 2 to 5, wherein inserting the retaining member into the receptacle comprises moving the retaining member along a curved path 7. The method of any one of claims 2 to 6, wherein the retaining member has rounded or chamfered edges.8. The method of any one of claims 2 to 7, wherein the retaining member comprises an arcuate surface that subtends a central angle of no less than 15 degrees or no more than degrees.23 fin The method of any one of claims 2 to 8, wherein the second part of the mould comprises a cavity for receiving part of the receptacle; placing the second part of the mould around the portion of the receptacle causes the receptacle to be retained within a mould cavity comprising the cavity of the first part of the mould and the cavity of the second part of the mould; the mould comprises an opening to the mould cavity, the opening having a central axis; and the retaining member, when inserted into the receptacle through the opening, is offset from the central axis in a direction toward the first part of the mould.10. The method of any one of claims 1 to 9, wherein the method comprises: terminating operation of the retaining mechanism; and applying a forming operation to the receptacle within the mould.I I The method of cl aim 10, wherein the forming operation comprises thermoforming 12. The method of claim 10 or 11, wherein the forming operating comprises: inserting an expandable member into the receptacle; and expanding the expandable member within the receptacle.13. The method of any one of claims Ito 12, wherein the receptacle is at least partially formed of paper pulp. 25 14 The method of any one of claims Ito 13, wherein: the second part of the mould comprises a cavity for receiving part of the receptacle; placing the second part of the mould around the portion of the receptacle causes the receptacle to be retained within a mould cavity comprising the cavity of the first part of the mould and the cavity of the second part of the mould; and a difference in maximum diameters of the mould cavity and the receptacle is no greater than 5 mm 15. A mould assembly comprising: a mould for receiving a receptacle, the mould comprising a first part and at least a second part moveable relative to the first part; and a retaining mechanism, wherein: the first part comprises a cavity for receiving part of the receptacle; the second part is moveable to surround a portion of the receptacle; and the retaining mechanism is operable to retain the receptacle within the cavity of the first part during movement of the second part.16. The mould assembly of claim 15, wherein: the retaining mechanism comprises a retaining member; the retaining member is moveable relative to the first part between a first position and a second position; the retaining member is located outside of the cavity in the first position; and the retaining member extends into the cavity in the second position such that, when the part of the receptable is received within the cavity, the retaining member extends into the receptacle to retain the receptacle in the cavity.17. The mould assembly of claim 16, wherein the mould assembly is configured such that, in the second position, the retaining member extends into a neck of the cavity.18 The mould assembly of claim 16 or 17, wherein the retaining member comprises an arcuate surface that subtends a central angle of no less than 15 degrees or no more than 180 degrees 19. The mould assembly of any one of claims 16 to 18, wherein the retaining member is moveable along a curved path between the first position and the second position.20. The mould assembly of claim 18 or 19, wherein the mould assembly is configured such that, in the second position, the arcuate surface faces the first part 21. The mould assembly of any one of claims 16 to 20, wherein: the second part of the mould comprises a cavity for receiving part of the receptacle; when the second part is moved to surround the portion of the receptacle, the mould comprises a mould cavity comprising the cavity of the first part and the cavity of the second part; the mould comprises an opening to the mould cavity, the opening having a central axis; and the retaining member, when in the second position, is offset from the central axis in a direction toward the first part of the mould 22. The mould assembly of any one of claims 16 to 21, wherein the retaining member has rounded or chamfered edges 23. The mould assembly of any one of claims 16 to 22, wherein the retaining member comprises an elongated finger that extends into the cavity in the second position.24. The mould assembly of any one of claims 16 to 23, wherein the mould assembly comprises a controller configured to cause movement of the retaining member from the first position to the second position, and then relative movement of the first part and the second part to place the second part around the portion of the receptable.The mould assembly of any one of claims 15 to 24, wherein the mould assembly comprises an expandable member operable to be inserted into the receptacle and expanded to apply a forming operation to the receptacle.