GB2625287A

GB2625287A - A mandrel system and method

Info

Publication number: GB2625287A
Application number: GB2218657.1A
Authority: GB
Inventors: Prozesky Daniel; Richard Ashcroft Theo; William Cooper Grant
Original assignee: Pulpex Ltd
Current assignee: Pulpex Ltd
Priority date: 2022-12-12
Filing date: 2022-12-12
Publication date: 2024-06-19
Also published as: WO2024126990A1; GB202218657D0

Abstract

A mandrel system 105 comprises a mandrel 115 locatable inside an expandable member 117, an idler 125 system moveable relative to the mandrel, and a connector 113 for connecting the mandrel system to a mould 103, an end of the mandrel is located inside the expandable member, the mandrel is moveable relative to the connector to vary a distance between the end of the mandrel and the connector, a length of the idler system is variable in response to movement of the mandrel relative to the connector. The idler may have a helical shape, and the mandrel may include one or more holes 129 through which a fluid is flowable to expand the expandable member. The idler may include a channel (139, fig 3) for guiding the fluid from a first end to a second end of the idler. The mandrel maybe rotatable relative to the connector to twist the expandable member around the mandrel. The method may include providing a partially formed receptacle within the mould, expanding the expandable member so as to urge the partially formed receptacle against an inner surface of the mould, the receptacle maybe formed of paper pulp.

Description

A MANDREL SYSTEM AND METHOD

TECHNICAL FIELD

The present invention relates to a mandrel system for use with a mould to mould a receptacle and a method

BACKGROUND

A mandrel system may be inserted into a mould in order for an expandable member of the mandrel system to be expanded to apply a forming operation to a partially formed receptacle, such as a bottle, located within the mould. In some examples, after the forming operation has been applied, the mandrel system may be withdrawn from the mould.

SUMMARY

According to a first aspect of the present invention, there is provided a mandrel system for use with a mould to mould a receptacle, the mandrel system comprising a mandrel locatable inside an expandable member, an idler system moveable relative to the mandrel to facilitate relative movement between the mandrel and the expandable member in use, and a connector for connecting the mandrel system to the mould. When the mandrel is located inside the expandable member, an end of the mandrel is located inside the expandable member; the mandrel is moveable relative to the connector to vary a distance between the end of the mandrel and the connector; and a length of the idler system is variable in response to movement of the mandrel relative to the connector.

In mandrel systems without an idler system, the expandable member may contact the mandrel during relative movement between the expandable member and the mandrel, which may occur, for example, when the expandable member is manipulated during insertion into the mould. This contact may generate friction between the mandrel and the expandable member, which may damage the expandable member. Additionally, this friction may cause portions of the expandable member to bind to the mandrel which may inhibit the relative motion between the expandable member and the mandrel and thereby the manipulation of the expandable member. The idler system may facilitate the relative movement because the expandable member can contact the idler system instead of the mandrel. As the idler system is moveable relative to the mandrel (for example, the idler system may be slidable relative to the mandrel), despite the potentially high friction contact between the idler system and the expandable member, the idler system (and thereby the expandable member) can move relative to the mandrel.

However, as the mandrel moves relative to the connector to vary the distance between the end of the mandrel and the connector, the length of mandrel which is exposed to contact with the expandable member may also vary. Therefore, in idler systems with a fixed length, as the mandrel moves, the idler system could be insufficiently long to cover the full extent of the mandrel which could contact the expandable member. Thereby, portions of the mandrel may come into contact with the expandable member. This may result in idler systems of a fixed length being less effective at reducing friction in a 1_5 mandrel system with a moveable mandrel.

Providing an idler system with a length which varies in response to movement of the mandrel may provide improved friction reduction in a mandrel system with a moveable mandrel than a fixed length idler system. Specifically, as the mandrel moves relative to the connector, the extent of the mandrel which could contact the expandable member may increase. With the variable length idler system, the length of the idler system could increase such that this increased length of exposed mandrel is covered by the idler system. This may reduce the likelihood of the movement of the mandrel relative to the expandable member being inhibited or the expandable member being damaged due to friction.

By varying the distance between the connector and the end of the mandrel, the length of mandrel which extends into the expandable member may be varied This may enable the same mandrel to be used with a range of expandable members having different lengths. k other examples, varying the distance may vary the width of the expandable member. For example, the expandable member may be connected to the connector and the end of the mandrel. Thereby, increasing the distance may result in the length of the expandable member increasing and result in a decrease in the width of the expandable member due to the Poisson effect. Decreasing the distance may result in a reduction in the length and an associated increase in the width of the expandable member. Varying the width of the expandable member may facilitate insertion of the expandable member into the mould and withdrawal of the expandable member from the mould.

Optionally, the mandrel system is for use with a mould to mould a bottle.

Optionally, the idler system is mounted to the mandrel such that movement of the mandrel relative to the connector causes the length of the idler system to vary. As a result, the length of the idler system may vary without requiring extra components and/or inputs from an operator in addition to those required to move the mandrel. This may reduce the time required to operate the mandrel system and thereby increase the throughput of a process employing the mandrel system and/or reduce the complexity of the mandrel system.

Optionally, the idler system comprises an idler, and a length of the idler is variable to vary the length of the idler system. As a result, the functionality of a variable length idler system may be added to an existing mandrel system without extensive modification of the existing mandrel system by simply adding the variable length idler to the existing mandrel system. In contrast, retrofitting a variable length mandrel system which requires other components to achieve the variable length of the idler system, for example a storage area, may require extensive modification of the existing mandrel system.

Optionally, the idler is changeable between a first configuration and a second configuration, the length of the idler is greater in the second configuration than in the first configuration, and movement of the mandrel relative to the connector causes the idler to change between the first configuration and the second configuration. As a result, the length of the idler and thereby the idler system may vary without requiring inputs from an operator in addition to those required to move the mandrel. This may reduce the time required to operate the mandrel system and thereby increase the throughput of a process employing the mandrel system.

Optionally, the idler has a helical shape. A helical shape may provide several benefits. Firstly, the helical shape may enable the idler to act as a spring. This may provide a mechanism for the length of the idler system to vary in response to the movement of the mandrel without requiring additional systems or operator input. This may simplify the mandrel system and simplify the use of the mandrel system. Secondly, the helical shape may enable the idler to surround the mandrel and thereby further inhibit contact between the mandrel and the expandable member, whilst also providing spaces for fluid to flow from the mandrel to the expandable member to expand the expandable member.

Optionally, the idler comprises a first turn and a second turn, and a clearance between the first turn and the second turn is no greater than 5.5 mm when the idler is in the second configuration. When the expandable member contacts the idler system, there is a risk that the expandable member may pass into a gap between the turns of the helical shape of the idler. When the idler subsequently moves from the second configuration to the first configuration (and decreases in length), there is a risk that the expandable member located in the gap may become trapped between the turns of the idler. The likelihood of the trapping occurring increases as the clearance between the turns gets larger, and thereby the size of the gap into which the expandable member can pass, increases. By providing a clearance of no greater than 5.5 mm, the likelihood of the expandable member becoming trapped between the turns of the idler may be reduced compared with a clearance of greater than 5.5 mm. Reducing trapping of the expandable member may beneficially reduce the likelihood of the expandable member being damaged by the idler, and the likelihood of the idler inhibiting the movement of the expandable member.

Optionally, the idler has a length of no less than 26.5 mm when in the second configuration.

Optionally, the idler system comprises an idler, and a storage area for storing the idler, and the length of the idler system is varied by moving the idler to and from the storage area. Moving the idler to and from the storage area to vary the length of the idler system may avoid the need to hold the idler in tension or compression in order to achieve the change in length of the idler and thereby the length of the idler system This may reduce the force applied to the idler which may improve the longevity of the idler.

Optionally, the idler has a fixed length. As a result, the longevity of the idler may be improved compared with a variable length idler. Specifically, the varying of the length of the variable length idler may fatigue the variable length idler which may lead to damage and failure. Additionally, a fixed length idler may be cheaper and simpler to manufacture than a variable length idler.

Optionally, the idler has rounded or chamfered edges. As a result, the likelihood of the expandable member being damaged, for example punctured or torn, by the idler is reduced compared with, for example, an idler with sharp edges.

Optionally, the mandrel comprises one or more holes through which a fluid is flowable in use from an interior of the mandrel to an exterior of the mandrel to expand the expandable member, and the idler comprises a channel for guiding the fluid from a first end of the idler to a second end of the idler, the channel defined on a side of the idler which faces the mandrel. The expandable member may contact portions of the idler system and, due to the friction generated between the expandable member and the idler system, may bind to the idler system. This may block the flow of fluid out of the blocked portions of the idler system. By providing the channel, the fluid can be guided around these blocked portions and thereby facilitate the flow of fluid into the expandable member.

Optionally, the idler has a maximum thickness perpendicular to a length of the mandrel of no greater than 2.3 mm. As the idler system is located inside the expandable member, the minimum width of the expandable member may be limited by the maximum thickness of the idler, Therefore, the minimum width of the expandable member may be reduced compared with an idler having a greater thickness.

Optionally, the mandrel system comprises the expandable member.

Optionally, the mandrel is rotatable relative to the connector to twist the expandable member around the mandrel. By twisting the expandable member around the mandrel, a larger variation in the width of the expandable member may be achieved than would otherwise be possible without twisting the expandable member. This may enable the mandrel system to be used with a greater range of mould geometries. Specifically, some moulds may have relatively small openings but relatively wide mould cavities. In these cases, a relatively wide expandable member would be required to sufficiently fill these moulds. However, the expandable member would also need to be sufficiently small to be inserted and withdrawn from the mould via the relatively small opening. By twisting the expandable member around the mandrel, the mandrel system may comprise a relatively wide expandable member, and the width of the expandable member may nevertheless be reduced to enable the expandable member to be inserted and withdrawn through the relatively small opening of the mould.

In systems without an idler system, as the expandable member is twisted around the mandrel, portions of the expandable member may come into contact with the mandrel.

Friction generated at these contact points may limit further twisting and thereby prevent further width variation. Providing the idler system may mitigate this friction. Specifically, the expandable member may contact the idler system rather than the mandrel. The idler system may then rotate relative to the mandrel and with the expandable member to enable the expandable member to rotate relative to the mandrel and thereby twist around the mandrel. Providing an idler system with a length which varies in response to movement of the mandrel may provide this improved friction reduction even as the mandrel is moved to vary the width of the expandable member.

Optionally, the idler system is rotatable relative to the mandrel.

Optionally, the idler system comprises a plurality of discrete idlers, and each idler is rotatable relative to the mandrel to facilitate twisting of the expandable member around the mandrel. As a result, during twisting, the material of the expandable member may be more evenly distributed along the length of the mandrel which may reduce occurrence of bunching of the material. Thereby, the minimum width that the expandable member is able to achieve may be reduced. In contrast, if only a single idler were used, the expandable member may bind to portions of the idler which may result in bunching of the material This bunching of the material may inhibit the twisting of the expandable member.

Optionally, a length of each idler is variable to adjust the length of the idler system, each idler has a helical shape and is moveable between a first configuration and a second configuration, the length of each idler is greater in the second configuration than in the first configuration, the mandrel system is configured to apply a force to each idler to move each idler from the second configuration to the first configuration, and each idler is configured to move from the first configuration to the second configuration in the absence of the force. The mandrel may be moved in a first direction to apply the force to the idlers and move the idlers towards the first configuration. The mandrel may be moved in a second direction to remove the force from the idlers and allow the idlers to move towards the second configuration.. By holding the idlers in compression rather than tension, the idlers may be simplified compared with an arrangement in which the idlers were held in tension. Specifically, to enable the idlers to move relative to one another whilst held in tension, the idlers may need to be connected to each other by mechanisms which enabled both relative movement and the transfer of a tensile force between the idlers. This mechanism may complicate the idlers.

Optionally, the idler system comprises a storage area for storing the idlers, the length of the idler system is varied by moving at least one of the idlers to or from the storage area, the idlers are stacked along the length of the mandrel, movement of the end of the mandrel away from the storage area causes one of the idlers to move from the storage area and increase the length of the idler system, and movement of the end of the mandrel towards the storage area causes one of the idlers to move to the storage area and decrease the length of the idler system. This may provide a mechanism for moving an idler to and from the storage area without requiring additional systems or operator input. This may simplify the mandrel system and simplify the use of the mandrel system. Additionally, as the idlers are stacked, gaps between the idlers are removed which may reduce the likelihood of the expandable member becoming trapped between the idlers and thereby inhibiting movement of the expandable member or damaging the expandable member.

Optionally, the mandrel system comprises a stopping mechanism for stopping the idlers from moving beyond the end of the mandrel, and one of the idlers abuts the stopping mechanism such that movement of the mandrel relative to the connector causes at least one of the idlers to move to or from the storage area and vary the length of the idler system.

Optionally, movement of the mandrel relative to the connector varies a width and a length of the expandable member. Varying the width and length of the expandable member may enable the width of the expandable member to be varied to best suit the requirements of a manufacturing process which employs the mandrel system. For example, reducing the width of the expandable member may be beneficial in facilitating passage of the expandable member through an opening of the mould which may occur when the mandrel system is inserted into, and subsequently withdrawn from, the mould. Reducing the width may enable the expandable member to pass through the opening without contacting the mould and thereby damaging the expandable member. Additionally, in the case where a partially formed receptacle is located within the mould and the expandable member is inserted into the partially formed receptacle to be expanded so as to urge the partially formed receptacle against an inner surface of the mould during a process to form the receptacle from the partially formed receptacle, reducing the width may reduce the likelihood of the expandable member contacting and damaging the receptacle during insertion and/or withdrawal. Moving the mandrel relative to the connector to increase the width of the expandable member prior to inserting fluid into the expandable member to expand the expandable member may be beneficial during the expansion as the expandable member may be able to expand relatively uninhibited by the mandrel. Uninhibited expansion of the expandable member may improve the magnitude and uniformity of a pressing force applied by the expandable member to the partially formed receptacle. Additionally, uninhibited expansion may reduce stress concentrations in the expandable member which may damage or fatigue the expandable member and thereby the longevity of the expandable member may be improved. Increasing the length of the expandable member may place the expandable member under tension which may reduce the amount of slack in the expandable member. Thereby, the expandable member may be less likely to contact and damage the partially formed receptacle during insertion and/or withdrawal.

Optionally, the movement of the mandrel system to vary the length of the expandable member causes the width of the expandable member to vary. For example, increasing the length of the expandable member may cause an associated decrease in the width of the expandable member. Decreasing the length of the expandable member may cause an associated increase in the width of the expandable member.

According to a second aspect of the present invention, there is provided a receptacle mould system mandrel idler, wherein a length of the idler is variable.

Optionally, the idler has a helical shape.

Optionally, the idler comprises a first turn and a second turn, and a clearance between the first turn and the second turn is no greater than 5.5 mm.

Optionally, the turns have rounded or chamfered edges.

Optionally, the idler comprises an aperture for receiving a mandrel, and the idler comprises a channel for guiding fluid from a first end of the idler to a second end of the idler, the channel defined on a side of the idler which faces the aperture.

According to a third aspect of the present invention, there is provided a method comprising providing a mandrel system having a mandrel, a connector for connecting the mandrel system to a mould, and an idler system, an end of the mandrel being locatable inside an expandable member. The method comprises moving the mandrel relative to the connector to vary a distance between the end of the mandrel and the connector, and varying a length of the idler system in response to the moving the mandrel relative to the connector, Optionally, the method comprises providing a mould, providing a partially formed receptacle within the mould, providing the expandable member and mandrel system in the receptacle, and expanding the expandable member so as to urge the partially formed receptacle against an inner surface of the mould during a process to form a receptacle from the partially formed receptacle.

Optionally, the receptacle is a bottle.

Optionally, the partially formed receptacle is formed, at least partially, of paper pulp.

Optionally, the method comprises applying heat to the partially formed receptacle during the expanding the expandable member. Thereby a thermoforming operation is applied to the partially formed receptacle. Thermoforming may improve the mechanical properties of the receptacle, such as stiffness, as well as the surface finish of the receptacle.

According to a fourth aspect of the present invention, there is provided a receptacle obtainable or obtained from a fabrication method comprising the method according to the third aspect of the present invention.

Optionally, the receptacle is a bottle.

The fabrication method may comprise at least one additional process. The at least one additional process may comprise coating and drying the receptacle to produce a coated receptacle. The at least one additional process may comprise applying a closure to the receptacle, or the coated receptacle.

Optional features of aspects of the present invention may be equally applied to other aspects of the present invention, where appropriate.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of an example process for making bottles from paper pulp; Figure 2 shows a simplified section view of an example mould system; Figure 3 shows a perspective view of an idler of the example mould system; Figure 4 shows a side view of the idler; Figures 5(a) to (h) show, by way of simplified sections, different stages in the insertion and withdrawal of a mandrel system from a mould of the mould system, Figure 6 shows a simplified section view of an example alternative mandrel system; Figure 7 shows a side view of an idler of the example alternative mandrel system, Figure 8 shows a top view of the idler of the example alternative mandrel system; and Figures 9 (a) to (h) show, by way of simplified sections, different stages in the insertion and withdrawal of the example alternative mandrel system from the mould.

DETAILED DESCRIPTION

The following description presents exemplary embodiments and, together with the drawings, serves to explain principles of embodiments of the invention.

Figure 1 shows a process for making 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 more additives includes a shorting agent, such as alicylketene dimer (AKD). 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 0.3 we)/0 with respect to the total dry mass of the 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 firing 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 with 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 bottle 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 drying 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 system 101 which may be used to thermoform the self-supporting moulded receptacle 22 discussed above. The mould system comprises a mould 103, a mandrel system 105, a pump 107 and a line 109.

The mould 103 comprises a first part and a second part. In other examples, the mould may comprise more than two parts. The two parts are separable so as to open the mould 103. Each part comprises a cavity and a heater (not shown). When the two parts are brought together to close the mould 103, a mould cavity 111 is created within the mould 103 that comprises the cavities of the first part and the second part. The mould comprises an opening to the mould cavity 111. The heaters are operable to heat the two parts of the mould and thereby heat the mould cavity 111.

The mandrel system 105 comprises a connector 113, a mandrel 115, an expandable member 117, a first actuator 119, a second actuator 121, an idler system 125 and a controller 127.

The connector 113 comprises a bore that extends through the connector 113 from a top to a bottom of the connector 113 An annular seal (not shown) is located within the bore and provides a seal between the connector 113 and the mandrel 115. The seal is a low-friction seal and permits movement of the mandrel 115 relative to the connector 113. As described below in more detail, the mandrel 115 moves relative to the connector 113 when inserting and withdrawing the mandrel 115 and expandable member 117 from the mould 103 The mandrel 115 comprises a cylindrical tube. A plurality of holes 129 are formed along the length of the tube. The holes 129 are located along a lower portion of the tube and extend radially through the tube to allow fluid to flow from the interior of the mandrel 115 to the exterior of the mandrel 115. The mandrel 115 extends through the bore in the connector 113 and into the expandable member 117 such that a lower portion of the mandrel 115 is located within the expandable member 117. A lower end of the mandrel 115, i.e., the end of the mandrel 115 located within the expandable member 117, is connected to the expandable member 117. The mandrel 115 is free to move relative to the connector 113. In particular, the mandrel 115 is free to move up and down within the bore, and to rotate within the bore.

The expandable member 117 comprises an inflatable member in the form of an el astomeri c bladder. The bladder comprises a neck portion and a body portion. The neck portion is sealingly connected to the bottom of the connector 113. The neck portion has a smaller diameter than the body portion. In other examples, the bladder may comprise a single portion of constant diameter.

The first actuator 119 is located on the connector 113 and is coupled to the mandrel 115. Operation of the first actuator 119 causes the mandrel 115 to move linearly, relative to the connector 113, along a longitudinal axis of the mandrel 115. Linear movement of the mandrel 115 along the longitudinal axis of the mandrel 115 varies a distance 131 between the lower end of the mandrel 115 and the bottom of the connector 113. In this example, the first actuator 119 comprises an electric motor and a transmission (e.g., gears, friction wheel, and/or rack and pinion) for transmitting torque generated by the electric motor to the mandrel 115. In other examples, the first actuator 119 may comprise a hydraulic or pneumatic system for moving the mandrel 115 relative to the connector 113.

The second actuator 121 is located at a top end of the mandrel 115 and is coupled to the mandrel 115. Operation of the second actuator 121 causes the mandrel 115 to rotate, relative to the connector 113, about the longitudinal axis of the mandrel 115. In this example, the second actuator 121 comprises an electric motor and a transmission (e.g., gears, friction wheel, and/or rack and pinion) for transmitting torque generated by the electric motor to the mandrel 115. In other examples, the second actuator 121 may comprise a hydraulic or pneumatic system for rotating the mandrel 115 relative to the connector 113.

The idler system 125 comprises multiple idlers 133. Turning now to Figures 3 and 4, each idler 133 comprises two end portions 135, a main portion 137 which extends between the two end portions 135, an aperture 138 and multiple channels 139 which are each defined by multiple recesses 140.

The end portions 135 each have an annular shape. The main portion 137 has a helical shape and comprises multiple turns 141. When the idler 133 is in an extended configuration (discussed below) the spacing 143 between adjacent turns 141 is no greater than 5.5 mm and a length 145 of the idler 133 (measured between a top end and a bottom end of the idler 133) is no greater than 26.5 mm. The aperture 138 extends between the two end portions 135 and inside of the main portion 137. The aperture 138 has a diameter which is greater than a diameter of the mandrel 115 such that, when mounted to the mandrel 115 (as discussed in more detail below) the idler 133 is rotatable around the mandrel 115. In this example, edges 149 of a side of the idler 133 which faces away from the aperture 138 are sharp. Equally, in other examples, edges 149 of the idler 133 may be rounded or chamfered. The idler 133 has a maximum thickness 151 perpendicular to a longitudinal axis of the idler 133 (and thereby, when the idler 133 is mounted to the mandrel 115, perpendicular to the length of the mandrel 115) of no greater than 2.3 mm. The idler 133 is formed from Polytetrafluoroethylene (PTFE) which may reduce the friction between the idler 133 and other components of the mandrel system 105. Equally, in other examples, the idler may comprise other materials.

Each channel 139 is defined on a side of the idler 133 which faces towards the aperture 138. Each channel 139 extends from the bottom end of the idler 133 to the top end of the idler 133. As shown in Figures 3 and 4, each channel 139 is intermittent. Specifically, each channel 139 is defined by multiple recesses 140 which are each defined on an inside of one of the end portions 135 and the turns 141.

The idler 133 is changeable between a compressed configuration and an extended configuration (shown in Figures 3 and 4). The length 145 of the idler 133 measured between the top end and the bottom end of the idler 133 is greater in the extended configuration than the compressed configuration. The helical shape of the main portion 137 enables the idler 133 to operate as a spring. Specifically, the idler 133 operates as a compression spring and, in the absence of a force applied by the mandrel system 105, move from the compressed configuration to the extended configuration.

The idler system 125 is mounted to the lower portion of the mandrel 115 such that the mandrel 115 extends through the aperture 138 of each idler 133. The idlers 133 are stacked along the lower portion of the mandrel 115 such that each idler 133 abuts an adjacent idler 133, a topmost idler 133 abuts the bottom of the connector 113, and a bottommost idler 133 abuts the expandable member 117 at the lower end of the mandrel 115. Thereby, the idler system 125 covers the portion of the mandrel 115 which is located between the connector 113 and the lower end of the mandrel 115. As discussed below in more detail below, this mounting arrangement enables movement of the mandrel 115 relative to the connector 113 to cause the length of the idler system 125 to vary. In this example, the length of the idler system 125 is the sum of the individual lengths 145 of the idlers 133, and is equivalent to the distance 131 between the connector 113 and the lower end of the mandrel 115.

The controller 127 controls the operation of the actuators 119,121 and thereby the movement of the mandrel 115 relative to the connector 113 The controller U7 also controls the pump 107, the heaters, and a robotic arm (not shown), which moves the connector 113 relative to the mould 103.

The pump 107 comprises a cylinder which displaces a fluid in the line 109. In some examples, the fluid is one of air, water, or oil. As the line 109 is connected to the top of the mandrel 115, displacing the fluid causes the pump 107 to supply a fluid, ideally a pressurised fluid, to the interior of the mandrel 115. The pressurised fluid then flows through the holes 129 in the mandrel 115 and into the expandable member 117. Thereby, the pump 107 is used to expand the expandable member 117. The pump 107 is also capable of operating in the opposite direction to withdraw the fluid from the expandable member 117 and thereby collapse and contract the expandable member 117.

Use of the mould system 101 will now be described with reference to Figure 5. The controller 127 controls the heaters to heat the two parts of the mould 103. As shown in Figure 5(a), the two parts of the mould 103 are then closed around a partially formed receptacle 22 such that the partially formed receptacle 22 is located inside the mould cavity 111. The partially formed receptacle 22 has the shape of a bottle. At this stage, the mandrel system 105 is located outside of the mould cavity 111. Additionally, the distance 131 between the lower end of the mandrel 115 and the connector 113 is less than the sum of the lengths 145 of the idlers 133 if the idlers 133 were in their expanded configurations.

Therefore, at this stage, the idlers 133 are in their compressed configurations. To maintain the idlers 133 in their compressed configurations, the first actuator 119 applies a compressive force to the idler system 125 via the connector 113 and the expandable member 117.

Turning now to Figure 5(b), the controller 127 controls the first actuator 127 to move the mandrel 115 down relative to the connector 113 and thereby increase the distance 131 between the connector 113 and the lower end of the mandrel 115. As the mandrel 115 moves down, the lower end of the mandrel 115 forces the bottom of the expandable member 117 down, which increases the length of the expandable member 117. This increase in length of the expandable member 117 results in a corresponding reduction in the width of the expandable member 117. As the distance HI between the connector 113 and the lower end of the mandrel 115 increases, the compressive force applied to the idler system 125 decreases and the idlers 133 move towards their expanded configuration. Thereby, the length of the idler system 125 increases such that the portion of the mandrel 115 located between the connector 113 and the lower end of the mandrel remains covered by the idler system 125. Concurrently, the controller 127 operates the second actuator 121 to rotate the mandrel 115 relative to the connector 113. Due to the expandable member 117 being attached to the end of the mandrel 115, the rotation causes the expandable member 117 to twist around the mandrel 115 and further reduce the width of the expandable member 117.

The controller 127 then controls the actuators 119, 121 to halt the downward motion and rotation of the mandrel 115. At this stage, the width of the expandable member 117 is less than the width of the opening of the mould 103. Thereby, the mandrel 115 and expandable member 117 may pass through the opening of the mould 103 without the expandable member 117 contacting the mould 103 or the partially formed receptacle 22.

Turning now to Figure 5(c), the controller 127 then controls the robotic arm to move the connector 113 down and toward the mould 103 until the connector contacts and connects with the top of the mould 103 (which is shown in Figure 5(d)). As the connector 1 1 3 moves down, the mandrel 115 and the expandable member 117 are inserted into the mould cavity 111 through the opening. Due to the previous downward motion of the mandrel 115 relative to the connector 113 (discussed with reference to Figure 5(b)), the length of the mandrel 115 is too great to fit within the mould cavity 111. Therefore, once a predetermined length of the mandrel 115 has been inserted into the mould cavity 111, the controller 127 operates the first actuator 119 to move the mandrel 115 up relative to the connector 113. The upward movement of the mandrel 115 relative to the connector 113 causes the distance 131 between the connector 113 and the lower end of the mandrel 115 to decrease. As the distance 131 between the connector 113 and the lower end of the mandrel 115 decreases, the first actuator 119 reapplies the compressive force to the idler system 125 and the idlers 133 move towards their compressed configurations. Thereby, the length of the idler system H5 decreases. Additionally, the upward movement of the mandrel 115 relative to the connector 113 causes the length of the expandable member 117 to decrease and the width of the expandable member 117 to increase. The controller 127 then operates the second actuator 121 to rotate the mandrel 115 relative to the connector 113 to untwist the expandable member 117 from around the mandrel 115. This then causes the width of the expandable member 117 to further increase.

With the expandable member 117 now positioned within the mould cavity, a forming operation is performed on the partially formed receptacle 22 (Figure 5(e)). The controller 127 controls the pump 107 to supply the pressurised fluid to the mandrel 115 which flows through the holes 129 in the mandrel 115. The fluid is then guided along the channels 139 in the idlers 133 and flows into the expandable member 117 via gaps between the turns 141 of the idlers 133. The idler 133 is such that the turns 141 are spaced even in a compressed configuration. In other examples, at least some of the turns of the idlers 133 may comprise notches through which the fluid can pass. Fluid entering the expandable member 117 causes the expandable member 117 to expand. With sufficient expansion, the expandable member 117 contacts the partially formed receptacle 22 and urges the partially formed receptacle 22 against an inner surface of the mould 103. As the controller 127 has previously controlled the heaters to heat the two parts of the mould 103, the partially formed receptacle 22 is heated. Thereby, the partially formed receptacle 22 is heated and compressed such that a receptacle 143 is formed from the partially formed receptacle 22.

Turning now to Figure 5(0, once the forming operation is complete, the controller 127 controls the pump 107 to withdraw the pressurised fluid from the expandable member 117, which causes the expandable member 117 to collapse and contract.

The controller 127 then controls the robotic arm to move the connector 113 upwards relative to the mould 103 (Figure 5(g)). Concurrently, the controller 127 controls the first actuator 119 to move the mandrel 115 downwards relative to the connector 113 at the same rate that the connector 113 is moved upwards, such that the end of the mandrel 115 is stationary relative to the mould 103. Thereby the distance 131 between the lower end of the mandrel 115 and the connector 113 increases. As the distance 131 between the connector 113 and the lower end of the mandrel 115 increases, the compressive force applied to the idler system 125 decreases and the idlers 133 move towards their expanded configuration. Thereby, the length of the idler system 125 increases such that the portion of the mandrel 115 located between the connector 113 and the lower end of the mandrel 115 remains covered by the idler system 125. Additionally, the length of the expandable member 117 is increased, which results in the width of the expandable member 117 being decreased. The controller 127 also controls the second actuator 121 to rotate the mandrel relative to the connector 113 such that the expandable member 117 is twisted around the mandrel 115 to further decrease the width of the expandable member 117. With the expandable member 117 elongated and twisted around the mandrel 115, the controller 127 controls the actuators 119,121 to halt movement of the mandrel 115 relative to the connector 113.

Turning now to Figure 5(h), the controller 127 controls the robotic an to move the connector 113 upwards relative to the mould 103 to withdraw the mandrel 115 and expandable member 117 from the mould 103 via the opening. Once the mandrel 115 and expandable member 117 are withdrawn from the mould 103, the mould 103 is opened by separating the two parts of the mould 103 and the receptacle 143 removed for further processing. For example, the receptacle 143 may be dried in a drying stage 29, as described above with reference to Figure 1 In mandrel systems without an idler system 125, the expandable member 117 may contact the mandrel 115 during relative movement between the expandable member 117 and the mandrel 115, which may occur, for example, when the expandable member 117 is manipulated during insertion into the mould 103. This contact may generate friction between the mandrel 115 and the expandable member 117, which may damage the expandable member 117. Additionally, this friction may cause portions of the expandable member 117 to bind to the mandrel 115 which may inhibit the relative motion between the expandable member 117 and the mandrel 115 and thereby the manipulation of the expandable member 117. The idler system 125 may facilitate the relative movement because the expandable member 117 can contact the idler system 125 instead of the mandrel 115. As the idler system 125 is moveable relative to the mandrel 115 (in the above example, the idlers 133 are rotatable), despite the potentially high friction contact between the idler system 125 and the expandable member 117, the idler system 125 (and thereby the expandable member) can move relative to the mandrel 115.

However, as the mandrel 115 moves relative to the connector 113 to vary the distance 131 between the end of the mandrel 115 and the connector 113, the length of mandrel 115 which is exposed to contact with the expandable member 117 may also vary. Therefore, in idler systems with a fixed length, as the mandrel 115 moves, the idler system could be insufficiently long to cover the full extent of the mandrel 115 which could contact the expandable member 117. Thereby, portions of the mandrel 115 may come into contact with the expandable member 117. This may result in idler systems of a fixed length being less effective at reducing friction in a mandrel system with a moveable mandrel 115.

Providing an idler system 125 with a length which varies in response to movement of the mandrel 115 may provide improved friction reduction in a mandrel system 105 with a moveable mandrel 115 than a fixed length idler system 125. Specifically, as the mandrel 115 moves relative to the connector 113, the extent of the mandrel 115 which could contact the expandable member 117 may increase. With the variable length idler system 125, the length of the idler system 125 could increase such that this increased length of exposed mandrel 115 is covered by the idler system 125. This may reduce the likelihood of the movement of the mandrel 115 relative to the expandable member 117 being inhibited or the expandable member 117 being damaged due to friction.

By varying the distance 131 between the connector 133 and the end of the mandrel 115, the width of the expandable member 117 is varied which may facilitate insertion of the expandable member 117 into the mould 103 and withdrawal of the expandable member 117 from the mould 103. In other examples, varying the distance 131 may vary the length of mandrel 115 which extends into the expandable member 117. This may enable the same mandrel 115 to be used with a range of expandable members having different lengths.

In the above example each idler 133 operates as a compression spring, and the first actuator 119 applies a compressive force to the idler system 125 to move each idler 133 from the extended configuration to the compressed configuration. In alternative examples, each idler 133 may operate as a tension spring, and the mandrel system 105 may apply a tensile force to move each idler 133 from the compressed configuration to the extended configuration. In these alternative examples, the idler system 125 may be connected to the connector 113 and the lower end of the mandrel 115, and the idlers 133 may be connected to one another.

In the above example, the idler system 125 is mounted to the mandrel 115 such that movement of mandrel 115 relative to the connector 113 causing the length of the idler system 125 to vary automatically. In other examples, the length of the idler system 125 may not vary automatically. For example, an operator may manually vary the length of the idler system 125.

In the above example, the lengths 145 of the idlers 213 are variable in order to 10 vary the length of the idler system 205. However, Figure 6 shows an alternative mandrel system 201 in which idlers 213 are moved to and from a storage area 211 to vary the length of the idler system 205.

The mandrel 115, expandable member 117, actuators 119, 121 and the controller 127 of the mandrel system 201 of Figure 6 are identical to those of the mandrel system 105 of Figure 2. However, the connector 203 and the idler system 205 are different as will be explained below.

The connector 203 comprises a bore 207 that extends through the connector 203 from a top to a bottom of the connector 203. An annular seal 209 is located within and towards a top of the bore 207 and provides a seal between the connector 203 and the mandrel 115. The annular seal 209 is a low-friction seal and permits movement of the mandrel 115 relative to the connector 203. A lower portion 211 of the bore 207 located beneath the annular seal 209 has a diameter which is greater than a diameter of each idler 213 of the idler system 205. Thereby, idlers 213 of the idler system 205 may be located within the lower portion bore 211. The lower portion of the bore 211 may be considered (and will be referred to hereafter as) a storage area 211 of the idler system 205.

The idler system 205 comprises multiple idlers 213 and the storage area 211. Turning now to Figure 7 and 8, each idler 213 has an annular shape and comprises multiple channels 215. Each idler 213 defines an aperture 217. The aperture 217 has a diameter which is greater than a diameter of the mandrel 115 such that, when mounted to the mandrel 115 (as discussed in more detail below) the idler 213 is rotatable around the mandrel 115. Edges 219 of a side of the idler 213 which faces away from the aperture 217 are rounded. The idler 213 has a maximum thickness 221 perpendicular to an axis which extends between a top end and a bottom end of the idler 213 (and thereby, when the idler 213 is mounted to the mandrel 115, perpendicular to the length of the mandrel 115) of no greater than 2.3 mm.

Each channel 215 is defined on a side of the idler 213 which faces towards the aperture 217. Each channel 215 extends from the bottom end of the idler 213 to the top end of the idler 213.

In contrast to the idlers 133 of Figures 3 and 4, the idler 213 has a fixed length. Specifically, the length 223 measured between the top end of the idler 213 and the bottom end of the idler 213 is fixed.

The idler system 205 is mounted to the portion of the mandrel 115 which is beneath the annular seal 209 such that the mandrel 115 extends through the aperture 217 of each idler 213. The idlers 213 are stacked along the mandrel 115 such that each idler 213 abuts at least one adjacent idler 213, the topmost idler 213 is (at least partially) located within the storage area 211, and a bottommost idler 213 abuts the expandable member 117 at the lower end of the mandrel 115. Thereby, the idler system 205 covers the portion of the mandrel 115 which is located between the connector 203 and the lower end of the mandrel 115. As discussed in more detail below, this mounting arrangement enables movement of the mandrel 115 relative to the connector 203 to cause the length 225 of the idler system 205 to vary. The length 225 of the idler system 205 is the distance measured between the top of the storage area 211 (in this example, the bottom of the annular seal 209) and the bottom end of the bottommost idler 213.

Use of the alternative mandrel system 201 will now be described with reference to Figure 9. The controller 127 controls the heaters to heat the two parts of the mould 103. As shown in Figure 9(a), the two parts of the mould 103 are then closed around a partially formed receptacle 22 such that the partially formed receptacle 22 is located inside the mould cavity 111. The partially formed receptacle 22 has the shape of a bottle. At this stage, the alternative mandrel system 201 is located outside of the mould cavity 111. Additionally, multiple idlers 213 of the idler system 205 are located inside the storage area 211 Turning now to Figure 9(b), the controller 127 controls the first actuator 127 to move the mandrel 115 down relative to the connector 203 and thereby increase the distance between the connector 203 and the lower end of the mandrel 115. As the mandrel 115 moves down, the lower end of the mandrel 115 forces the bottom of the expandable member 117 down, which increases the length of the expandable member 117.

Additionally, the lower end of the mandrel 115 moves away from the storage area 211 which, due to gravity, causes idlers 213 previously located in the storage area 211 to move from the storage area 211. Thereby, the length 225 of the idler system 205 increases such that the mandrel 115 located between the connector 203 and the lower end of the mandrel 115 remains covered by the idler system 205. Concurrently, the controller 127 operates the second actuator 121 to rotate the mandrel 115 relative to the connector 203. Due to the expandable member 117 being attached to the end of the mandrel 115, the rotation causes the expandable member 117 to twist around the mandrel 115 and further reduce the width of the expandable member 117.

Turning now to Figure 9(c), the controller 127 then controls the robotic arm to move the connector 203 down and toward the mould 103 until the connector 203 contacts and connects with the top of the mould 103 (which is shown in Figure 9(d)) As the connector 203 moves down, the mandrel 115 and the expandable member 117 are inserted into the mould cavity 111 through the opening. Due to the previous downward motion of the mandrel 115 relative to the connector 203 (discussed with reference to Figure 9(b)), the length of the mandrel 115 is too great to fit within the mould cavity 111. Therefore, once a predetermined length of the mandrel 115 has been inserted into the mould cavity 111, the controller 127 operates the first actuator 119 to move the mandrel 115 up relative to the connector 203. The upward movement of the mandrel 115 relative to the connector 203 causes the lower end of the mandrel 115 to move towards the storage area 211, which causes idlers 213 previously located outside of the storage area 211 to move to the storage area 211. Thereby, the length 225 of the idler system 205 decreases. Additionally, the upward movement of the mandrel 115 relative to the connector 203 causes the length of the expandable member 117 to decrease and the width of the expandable member 117 to increase. The controller 127 then operates the second actuator 121 to rotate the mandrel 115 relative to the connector 203 to untwist the expandable member 117 from around the mandrel 115. This then causes the width of the expandable member 117 to further increase.

With the expandable member 117 now positioned within the mould cavity, a forming operation is performed on the partially formed receptacle 22 (Figure 5(e)). The controller 127 controls the pump 107 to supply the pressurised fluid to the mandrel 115 which flows through the holes 129 in the mandrel 115. The fluid is then guided along the channels 215 in the idlers 213 towards the top end and bottom end of each idler 213. Notches (not shown) located at the top end and/or the bottom end of each idler 213 then enable the fluid to pass into the expandable member 117. Fluid entering the expandable member 117 causes the expandable member 117 to expand. With sufficient expansion, the expandable member 117 contacts the partially formed receptacle 22 and urges the partially formed receptacle 22 against an inner surface of the mould 103. As the controller 127 has previously controlled the heaters to heat the two parts of the mould 103, the partially formed receptacle 22 is heated. Thereby, the partially formed receptacle 22 is heated and compressed such that a receptacle 143 is formed from the partially formed receptacle 22.

Turning now to Figure 9(1), once the forming operation is complete, the controller 127 controls the pump 107 to withdraw the pressurised fluid from the expandable member 117, which causes the expandable member 1 17 to collapse and contract.

The controller U7 then controls the robotic arm to move the connector 203 upwards relative to the mould 103 (Figure 9(g)). Concurrently, the controller 127 controls the first actuator 119 to move the mandrel 115 downwards relative to the connector 203 at the same rate that the connector 203 is moved upwards, such that the end of the mandrel 115 is stationary relative to the mould 103. Thereby the lower end of the mandrel 115 moves away from the storage area 211 which causes idlers 213 previously located in the storage area 211 to move from the storage area 211. Thereby, the length 225 of the idler system 205 increases such that the portion of the mandrel 115 located between the connector 203 and the lower end of the mandrel 115 remains covered by the idler system 205. Additionally, the length of the expandable member 117 is increased, which results in the width of the expandable member 117 being decreased. The controller 127 also controls the second actuator 121 to rotate the mandrel 115 relative to the connector such that the expandable member 117 is twisted around the mandrel 115 to further decrease the width of the expandable member 117. With the expandable member 117 elongated and twisted around the mandrel 115, the controller 127 controls the actuators 119,121 to halt movement of the mandrel I IS relative to the connector 203.

Turning now to Figure 9(h), the controller 127 controls the robotic arm to move the connector 203 upwards relative to the mould 103 to withdraw the mandrel 115 and expandable member 117 from the mould 103 via the opening. Once the mandrel 115 and expandable member 117 are withdrawn from the mould 103, the mould 103 is opened by separating the two parts of the mould 103 and the receptacle 143 removed for further processing. For example, the receptacle 143 may be dried in a drying stage 29, as described above with reference to Figure 1.

In the example of Figure 6, the top of the storage area 211 is defined by the bottom of the annual seal 209. In other examples, the top of the storage area 211 may be defined by other features of the connector 203, such as a change in diameter of the bore of the connector 203.

In the above examples, the expandable member 117 is attached to the lower end of the mandrel 115 and the bottommost idler 213 abuts the expandable member 117 at the lower end of the mandrel 115. However, in other examples, the expandable member 117 may be detachably attached the expandable member 117. In these examples, the mandrel 115 comprises a stopping mechanism (for example a projection) which stops the idlers 213 from moving beyond the lower end of the mandrel 115, and the bottommost idler 213 abuts the stopping mechanism.

In the above examples, the idlers 213 are rotatable relative to the mandrel 115 In other examples, the idlers 213 may be slidable relative to the mandrel 115 In a more general sense, the idlers 213 may be said to be moveable relative to the mandrel 115.

Although the mandrel system 105 is described as part of a mould system 101 which may be used for thermoforming the self-supporting moulded receptacle 22, the mandrel system 105 may equally find utility in a mould system for forming the self-supporting moulded receptacle 22 from the fibre suspension, such as the porous mould 15 described above.

In the above examples, each idler is described as abutting at least one adjacent idler. However, in other examples, each idler may become separated from the adjacent idler in use. Therefore, each idler may not abut another idler and may instead be spaced from the adjacent idler.

Example embodiments of the present invention have been discussed, with reference to the example illustrated. However, it will be appreciated that variations and modifications may be made without departing from the scope of the invention as defined 20 by the appended claims.

Claims

CLAIMS: 1. A mandrel system for use with a mould to mould a receptacle, the mandrel system comprising: a mandrel locatable inside an expandable member; an idler system moveable relative to the mandrel to facilitate relative movement between the mandrel and the expandable member in use; and a connector for connecting the mandrel system to the mould, wherein: when the mandrel is located inside the expandable member, an end of the mandrel is located inside the expandable member; the mandrel is moveable relative to the connector to vary a distance between the end of the mandrel and the connector; and a length of the idler system is variable in response to movement of the mandrel relative to the connector.
2 The mandrel system of claim 1, wherein the idler system is mounted to the mandrel such that movement of the mandrel relative to the connector causes the length of the idler system to vary.
3. The mandrel system of claim 1 or claim 2, wherein: the idler system comprises an idler; and a length of the idler is variable to vary the length of the idler system.
4. The mandrel system of claim 3, wherein: the idler is changeable between a first configuration and a second configuration; the length of the idler is greater in the second configuration than in the first configuration; and movement of the mandrel relative to the connector causes the idler to change between the first configuration and the second configuration.The mandrel system of claim 4, wherein the idler has a helical shape The mandrel system of claim 5, wherein: the idler comprises a first turn and a second turn; and a clearance between the first turn and the second turn is no greater than 5.5mm when in the idler is in the second configuration.7. The mandrel system of claim 1 or claim 2, wherein: the idler system comprises an idler, and a storage area for storing the idler, and the length of the idler system is varied by moving the idler to and from the storage area The mandrel system of claim 7, wherein the idler has a fixed length 9 The mandrel system of any one of claims 3 to 2, wherein the idler has rounded or chamfered edges.10. The mandrel system of any one of claims 3 to 9, wherein: the mandrel comprises one or more holes through which a fluid is flowable in use from an interior of the mandrel to an exterior of the mandrel to expand the expandable member; and the idler comprises a channel for guiding the fluid from a first end of the idler to a second end of the idler, the channel defined on a side of the idler which faces the mandrel.11. The mandrel system of any one of claims 3 to 10, wherein the idler has a maximum thickness perpendicular to a length of the mandrel of no greater than 2.3 mm.12. The mandrel system of any one of claims 1 to 11, wherein the mandrel system comprises the expandable member.13. The mandrel system of claim 12, wherein the mandrel is rotatable relative to the connector to twist the expandable member around the mandrel 14. The mandrel system of claim 13, wherein: the idler system comprises a plurality of discrete idlers; and each idler is rotatable relative to the mandrel to facilitate twisting of the expandable member around the mandrel.15. The mandrel system of claim 14, wherein: a length of each idler is variable to vary the length of the idler system; each idler has a helical shape and is moveable between a first configuration and a second configuration the length of each idler is greater in the second configuration than in the first configuration; the mandrel system is configured to apply a force to each idler to move each idler from the second configuration to the first configuration; and each idler is configured to move from the first configuration to the second configuration in the absence of the force.16. The mandrel system of claim 14, wherein: the idler system comprises a storage area for storing the idlers; the length of the idler system is varied by moving at least one of the idlers to or from the storage area the idlers are stacked along the length of the mandrel; movement of the end of the mandrel away from the storage area causes one of the idlers to move from the storage area and increase the length of the idler system; and movement of the end of the mandrel towards the storage area causes one of the idlers to move to the storage area and decrease the length of the idler system.17. The mandrel system of any one of claims 12 to 16, wherein movement of the mandrel relative to the connector varies a width and a length of the expandable member.18. A receptacle mould system mandrel idler, wherein a length of the idler is variable.19 The receptacle mould system mandrel idler of claim 18, wherein the idler has a helical shape 20. The receptacle mould system mandrel idler of claim 19, wherein: the idler comprises a first turn and a second turn; and a clearance between the first turn and the second turn is no greater than 5.5 mm.21. The receptacle mould system mandrel idler of any one of claims 18 to 20 wherein: the idler comprises an aperture for receiving a mandrel; and the idler comprises a channel for guiding fluid from a first end of the idler to a second end of the idler, the channel defined on a side of the idler which faces the aperture.22. A method comprising: providing a mandrel system comprising a mandrel, a connector for connecting the mandrel system to a mould, and an idler system, an end of the mandrel being locatable inside an expandable member; moving the mandrel relative to the connector to vary a distance between the end of the mandrel and the connector; and varying a length of the idler system in response to the moving the mandrel relative to the connector.23. The method of claim 22, wherein the method comprises: providing a mould; providing a partially formed receptacle within the mould; providing the expandable member and mandrel system in the receptacle; and expanding the expandable member so as to urge the partially formed receptacle against an inner surface of the mould during a process to form a receptacle from the partially formed receptacle.24. The method of claim 23, wherein the partially formed receptacle is formed, at least partially, of paper pulp.A receptacle obtainable or obtained from a fabrication method comprising the method of any one of claims 22 to 24.