GB2463901A

GB2463901A - Mould assembly

Info

Publication number: GB2463901A
Application number: GB0817755A
Authority: GB
Inventors: Lawrence Thorpe; Kevin Leatherland
Original assignee: ATM AUTOMATION Ltd
Current assignee: ATM AUTOMATION Ltd
Priority date: 2008-09-27
Filing date: 2008-09-27
Publication date: 2010-03-31
Anticipated expiration: 2028-09-27
Also published as: GB2463901B; GB0817755D0

Abstract

An array of first mould parts 38 are releasably retained in a first retaining means 40, with an array of second mould parts releasably retained in a second retaining means 20. The two retaining means are bought together so as to bring the arrays of each mould part together whilst grippers 32 grip the first mould to maintain alignment. The assembled retainers can now be moved around together, without causing misalignment in the moulds. Also disclosed is a mould heating arrangement using multi point (72,fig.9) heat resistant wires to spread heat around a mould arrangement such as that already described.

Description

Mould Assembly Method and Apparatus The present invention relates to moulds to the creation of moulded parts and more particularly to a method and apparatus for assembling moulds. A specific use of such moulds may be in the manufacture of lenses.

The use of lenses which are designed to sit immediately adjacent a user's eye so as to cover the cornea has become widespread as an alternative to the use of spectacles.

Contact lenses of this type are typically formed of a moulded plastic material which is sufficiently soft that it can sit on a wearer's eye with minimal discomfort to the wearer.

The production of contact lenses requires a plurality of steps to be carried out in forming of the appropriate mould. A conventional mould typically comprises a male and female mould section which can be brought together to form a cavity into which the lens material is inserted for formation of the lens.

It will be appreciated that the precise shape of the lens is crucial to its use and so the formation and assembly of the mould for the lens is critical in ensuring that a suitable lens is produced. In a conventional lens mould manufacture process, the male and female parts of the mould are produced and brought together for subsequent processing steps such as curing and filling with the lens material. However the assembly of the male and female mould parts has typically required a bespoke assembly process to ensure the accurate alignment for lens moulding.

It is well known that the contour of the edge or lip of the lens is crucial in ensuring that a contact lens can be worn without discomfort to a user. A slight misalignment of the mould parts can cause lenses to be unusable.

Once the male and female mould parts have been formed, the parts are typically cured for a period of time prior to filling. The sealing of the mould so as to retain the contact lens material therein is conventionally achieved by pressing heated elements against a rim or flange portion of the contacting male and female mould parts. Current sealing techniques have been found to be relatively inaccurate and allow little control over the weld strength of the molten material.

It is an object of the present invention to provide an improved lens mould assembly process which obviates some or all of the above problems.

According to a first aspect of the present invention there is provided a mould assembly system comprising first retaining means having a plurality of formations for releasably retaining an array of first mould parts; second retaining means having a plurality of formations for releasably retaining an array of second mould parts; the second retaining means being moveable towards the first retaining means so as to bring the first and second arrays into proximate alignment for assembly of an array of moulds; wherein the second retaining means comprises gripping means for gripping the array of first mould parts such that the proximate alignment of said arrays of first and second moulded parts is maintained upon subsequent relative movement between the first and second retaining means.

The present invention is particularly advantageous in that male and female mould parts can be brought together and aligned for subsequent handling in a single process. Once brought together, the alignment of the mould parts can be accurately preserved by the gripping means such that subsequent realignment of the parts for later manufacturing steps may not be required.

In one embodiment, the mould assembly system is a lens mould assembly system.

According to one embodiment, the first retaining means comprises an array of apertures in which the array of first mould parts may be located. The array of apertures may be oriented and/or spaced to match the orientation and/or spacing of the array of second mould parts held by the second retaining means. The first mould parts may comprise a body portion and a peripheral rim or flange portion. The body portion may be shaped to be insertable into a corresponding aperture. The rim or flange portion may be arranged to contact the first retaining means adjacent the aperture so as to seat the body portion within said aperture.

The apertures may be arranged in a substantially circular array. The first retaining means may comprise a circular or annular body in which the apertures are formed. The diameter of the rim or flange portion may be greater than that of an aperture in the first retaining means.

The use of an array of apertures has been found to be beneficial in maintaining a predetermined alignment of the first mould parts within an array with very little tolerance.

Thus the array of first parts can be held for alignment in an accurate and predictable manner.

The first retaining means may further comprise one or more suction cups. The suction 1 0 cups may be arranged in an array such that they are aligned with the apertures. Thus the first mould parts can be located in the apertures and held therein by application of a suction cup thereto. The body portion of the first mould parts may be rounded. The suction cups may be applied to a rounded end of the body portion.

In one embodiment, the first retaining means comprises or is attachable to actuation means. The actuation means may be moveable with limited degrees of freedom. The actuation means may comprise a first robot which may be a 3-axis robot.

Typically the first and second mould parts are themselves moulded parts. The first and second moulded parts may be formed of a plastic material. The first mould parts may be female mould parts. The second mould parts may be male mould parts. The second mould parts may have a body portion which may be rounded in shape and a rim or flange portion which may protrude outwardly from the body portion. The second mould part may have a body portion which is shaped to fit within the first mould part so as to define an interior cavity for formation of a lens therein.

According to one embodiment, the second retaining means comprises a plurality of protrusions arranged in an array which substantially matches the orientation and/or spacing of the array of formations on the first retaining means. The protrusions may be shaped to receive the second mould parts thereon. The or each protrusion may have an opening therein for application of fluid pressure to a mould part located on the protrusion.

The opening may comprise a duct in fluid communication with a fluid pressure source.

The duct may be used to provide a negative pressure so as to releasably retain a mould part thereon.

The protrusions may be arranged in a substantially circular array. The protrusions may be mounted on an annular member.

In one embodiment, the second retaining means comprises or is attachable to actuation means which may comprises a 6-axis robot.

The gripping means may comprise opposing gripper members. The gripper members may comprise first and second fingers which may be pivotably mounted and actuable between open and closed positions. The gripper means may comprise a plurality of spaced grippers which may be mounted at different angular orientations. The grippers may be angularly spaced about an axis. The grippers may be mounted within or amongst the array of protrusions.

The first mould parts may have spacer members which connect the first mould parts within an array. The first mould parts may be formed as a tree' of moulded parts having a sprue or runner interconnecting those parts. The spacer members may be connected at a central point of the array and may extend radially outwards, terminating at a first mould part. The second mould parts may be devoid of such spacer members and may be moveable relative to other mould parts in an array.

The grippers may be arranged to grip one or more of the spacer members of the array of first mould parts during use. This has been found to be advantageous in that the array of first mould parts may be held in apertures in the first retaining means whilst presenting the spacer members for gripping by the second retaining means upon correct alignment therewith. Thus the first mould parts can be transferred from the first retaining means to the second retaining means substantially without interference whilst retaining the correct alignment. That is to say the first retaining means can hold the first mould parts at a position spaced from the region in which the gripper holds the first mould parts.

According to one embodiment the system further comprises a third retaining means for releasably retaining the array of second mould parts prior to pick up by the second retaining means. The third retaining means may comprise an array of cup formations in which the second mould parts are locatable. The cup formations may be arranged in a substantially circular array. The third retaining means may comprise actuation means for moving the array of second mould parts relative to the second retaining means.

The array of second mould parts may not have spacer members connecting the individual mould parts within the array. Thus the array may comprise individual mould parts correctly spaced and positioned as required.

Any of the actuation means described within this patent application may be machine controlled to perform a sequence of pre-programmed movements. The application of fluid pressure to either the first and/or second retaining means may be machine controlled in a similar manner or otherwise automated. The operation of the gripper means may be machine controlled in a similar manner or otherwise automated.

In one embodiment, the system may further comprise a tray arranged to receive the assembled array of first and second mould parts. The tray may have one or more recesses therein, the depth of the recess being substantially equal to the depth of the body portion of the first or second mould part. Alternatively the tray may comprise a planar member which may have an array of apertures therein for locating the assembled arrays thereon. In one embodiment the arrays may be stacked one on top of the other on a tray.

The recess may have a peripheral wall shaped to closely surround the array of mould parts. The peripheral wall may be curved and in one embodiment may be multiply curved. The peripheral wall may be shaped to maintain contact with a portion of each of the body portions of the first mould parts in the array. Thus the recess supports the array and prevents misalignment of the array inserted therein.

According to a second aspect of the present invention there is provided a method of manufacturing a mould assembly comprising: providing an array of first mould parts and an array of second mould parts; releasably retaining the array of first mould parts in first retaining means; releasably retaining the array of second mould parts in second retaining means; moving the second retaining means towards the first retaining means so as to bring the first and second arrays into proximate alignment for assembly of an array of moulds; wherein the second retaining means comprises gripping means for gripping the array of first mould parts such that the proximate alignment of said arrays of first and second moulded parts is maintained upon subsequent relative movement between the first and second retaining means.

Any of the optional features described above in relation to the first aspect may optionally be attributed to the second aspect.

According to a third aspect of the present invention, there is provided apparatus for assembly of first and second mould parts to form a mould, the apparatus comprising a support member having a plurality of conductive heater elements depending therefrom, the heater elements comprising a first arm depending from the support member at a first location and a second arm depending from the support member at a second location spaced from the first location, wherein the first and second arms are at least in part obliquely angled so as to form an apex for contact with one mould part so as to thereby heat the mould part for adhesion to the other mould part.

In one embodiment, the heater elements are spaced about a surface of the support member. The support member may be planar in form and may have a plurality of openings therein. The heater elements may be positioned on the support member for contact with a peripheral portion or flange of the first or second mould part.

The heater element may be formed of a unitary piece of material which is shaped to form the angled first and second arms. The heater element may be V-shaped in part.

The formation of an apex for heating the mould parts has been found to be beneficial in the accuracy of heating such that a weld similar to that of a spot weld can be achieved.

Thus the strength of the bond between the first and second mould parts can be better controlled than has been possible using conventional heating element designs.

Furthermore the heating element of the present invention has been found to retain less molten plastic upon retraction from the mould and thus is less prone to clogging and may require less cleaning.

The support member may be releasably attachable to actuation means for moving the support and heating elements towards and away from the mould parts. The support means may be attached to the actuation means using quick release means which may comprise a releasable clip, such as, for example, a C-clip.

Practicable embodiments of the present invention are described in further detail below by way of example with reference to the accompanying drawings, of which: Figure 1 shows a three dimensional view of third retaining means for use in conjunction with the present invention; Figure 2 shows a three dimensional view of the third retaining means mounted for use; Figure 3 shows a three dimensional view of a portion of second retaining means according to the present invention; Figure 4 shows a three dimensional view of first retaining means according to the present invention; Figure 5 shows a plan wireframe view of the first and second retaining means when aligned; Figure 6 shows a sectional view through plane A-A of figure 5; Figure 7 shows a three dimensional view of the second retaining means holding assembled mould arrays according to the present invention; Figure 8 shows a three dimensional view of heating apparatus according to the third aspect of the present invention; Figure 9 shows further detail of ringed portion A of figure 8; Figure 10 shows a plan view of a tray for use in conjunction with the present invention; and, Figure 11 shows a side view of the tray of figure 10.

The present invention provides for improvements in a method and system for formation of moulds, such as moulds for forming contact lenses or the like. The mould typically comprises male and female mould parts which are formed by a separate moulding process, such as for example injection moulding. The male and female mould parts are shaped such that, when they are correctly brought together, they form an internal mould cavity into which lens material can be inserted for formation of the desired lens.

The first and second parts are referred to below as respective female and male mould parts.

Turning firstly to figure 1, there is shown an embodiment of the third retaining means which comprises formation 10 for holding an array of male mould parts 12. The male mould parts 12 take the from of an open-ended body portion 13 which is curved at its closed end so as to define a cup-like body which is hollow. The open end of the male mould part has a peripheral rim 15 which extends outwardly around the circumference of the body 13.

Whilst not shown in figure 1, the male mould parts 12 also comprise an annular groove on the exterior periphery of the body portion towards its closed end. The groove is arranged to receive a ring seal member (not shown) in the form of an 0-ring, which is positioned to allow a seal between male and female mould parts as will be described below when the male and female parts are brought together.

The formation 10 takes the form of a body of revolution having a plurality of ports 14 therein. The ports are substantially cylindrical bores formed within the formation 10 of diameter and depth sufficient to receive the body portion of a male mould part 12. When the male moulded part 12 is inserted into a port 14 the rim 15 sits on the surface of the formation such that the body portion 13 is correctly located within the port. Thus the rim l5actsasa stop.

An array of male parts are typically formed by a conventional moulding process such that they have a runner of material interconnecting the male mould parts once formed. The male mould parts are de-gated by cutting away the runner using conventional cutting tools either before, during or after inserting the male mould parts into theformation 10.

Figure 2 shows a pair of formations 10 mounted on a support plate 16 in a side-by-side arrangement. This arrangement allows two arrays of mould parts to be manipulated at once as will be described below in further detail. The ports in each formation 10 are arranged in a substantially circular arrangement. A total of six ports are provided in each arrangement such that twelve mould parts can be accommodated at once by the retaining structure shown in figure 2. However it will be appreciated that more or less ports may be provided to suit different sizes and/or orientations or arrays.

In figure 2 it can be seen that a male mould part 12 has been inserted in each port such that the open end of the male mould parts are exposed for use. The support plate 16 has fixing means 18 for fixing the plate to a 3-axis robot (not shown) such that the plate can be moved between a first position in which the formations 10 receive the male mould parts 12 and a second position in which the male mould parts are transferred to the second retaining means shown in figure 3.

In figure 3 there is shown an embodiment of the second retaining means according to the present invention. This embodiment of the second retaining means is hereinafter referred to as a picker or gripper 20. The picker 20 comprises a support 22 in the form of a mounting plate, to which is mounted an upstanding picking means. The picking means comprises two operative parts for performing two separate picking operations.

The first picking means comprises an upstanding structure 24 which is annular in plan.

The structure has a circumferential wall which terminates at a ring-shaped mounting surface 26 facing away from support plate 22. On the mounting surface 26 are provided an array of protrusions 28. A total of six protrusions 28 are provided in a substantially circular array.

The protrusions 28 are generally dome-shaped and match the interior space within the male mould parts 12. Each protrusion has an air duct 30 therein which has an opening at the crest of the dome shaped protrusion, that is facing away from support plate 22.

The air duct 30 runs through the protrusion 28 and upstanding structure 24 (as can be seen in figure 6) and is in fluid communication with a negative pressure source (not shown). Various pumps are well known to people skilled in the art, and are freely available for creating a suitable suction within ducts 30 and will not be described in detail here.

The second picking means on picker unit 20 comprises a plurality of grippers 32. The grippers are mounted within the central opening in the upstanding structure 24. In this embodiment, the grippers are oriented at angular spacings about a central point. The grippers are oriented substantially tangentially. A total of three grippers 32 are provided in this embodiment although greater or fewer numbers of grippers may be provided dependent on the array of mould parts to be held.

It can be seen that the grippers 32 each comprise a pair of opposing finger members 34 which are pivotably mounted to a base 36. The opposing fingers 34 can be actuated by drive means between open and closed positions. The inner edges or faces of the gripper fingers may be shaped or profiled to facilitate entrapment of an array of mould parts therebetween as will be described below. It should be noted that the grippers are arranged to grip the sprue or runner which joins the female mould parts 38, rather than gripping the actual mould parts themselves.

The arrangement of figure 3 shows only one half of the picker unit 20 and it wilt be appreciated that the other half of the unit is essentially a mirror image of the half which is shown. Thus the picker 20 comprises a pair of upstanding structures 24 and associated grippers mounted in a side-by-side arrangement to match the adjacent arrays of ports shown in figure 2.

Figure 4 shows an embodiment of the first retaining means according to the present invention. This retaining unit 40 functions as a holder for the female mould parts 38 prior to transfer to the picker 20 as will be described below. The retaining unit 40 is mounted on a 3-axis robot (not shown) for movement between a first position in which the retaining unit receives the array of female mould parts 38 and a second position in which the retaining unit presents the female mould parts to the picker 20 for transfer thereto.

The retaining unit 42 is shown in use with a pair of arrays of female mould parts 38 located thereon.

The retaining unit 40 comprises a support member in the form of support. plate 42, which has mounting means 44 comprising a bolt which passes through the support plate for mounting the retaining unit to a robot for actuation thereof.

The support plate also comprises a plurality of air ducts therein for fluid communication with an array of suckers 46 which depend upwardly from the support plate 42. The suckers are of a conventional design and comprise an upstanding tubular neck portion and a flexible suction cup at the free end thereof. A common duct feeds the individual air ducts and exits the support plate at opening 48.

The support plate also supports an alignment member 50 which is spaced from the support plate by a plurality of arms 52. The alignment member is annular in shape and is positioned over the suckers 46 which are arranged in a circular array.

The alignment member 50 has a plurality of openings therein, which openings are arranged in an array which matches the array of protrusions 28 on the picker 20. In this embodiment, a circular array of six openings is provided in the alignment member 50.

The array of openings matches the array of suckers 46 such that each sucker is positioned beneath an opening and substantially coaxially therewith.

As can be seen in figure 4, the array of female mould parts 38 is joined by a tree of spacers 54 which comprises the sprue which connects the female mould parts when formed, for example by injection moulding. Each of the female mould parts 38 in the array is seated in a corresponding opening in the alignment member 50. The female mould parts are of similar to the shape of the male mould parts 12 described above and have a body portion 56 and a rim or flange 58. The size of the rim 58 is greater than that of the openings in the alignment member such that the rim contacts the surface of the alignment member to align the body portion therein.

The size of the female mould parts 38 is slightly larger than that of the male mould parts such that the male mould part can fit within a corresponding female mould part.

The spacing between the alignment member 50 and suction cups 46 is such that the suction cups can act on the body portion 56 of the female mould parts 38 when they are seated in the alignment member openings. It is considered an important functional feature of the present invention that the alignment member and the retaining means (for example the suction cups) can act in unison to maintain accurate alignment of the mould parts.

The operation of the system according to one embodiment of the present invention is described below.

The formation 10 is first provided with male mould parts as shown in figure 2 and moved into a position in which the male mould parts 12 are presented to the picker 20. The picker 20 is then moved into alignment with the formation 10 such that the protrusions 28 on the picker are inserted into the open end of the male mould parts held by the formation 10.

A negative pressure is then applied to the ducts 30 in the picker 20 such that the male mould parts are held on the array of protrusions and the picker 20 is then withdrawn from the formation 10 along with the male mould parts. At this stage the male mould parts are held on the protrusions 28.

A can be seen in figure 5, the picker 20 is then moved into alignment with the retaining unit 40, which holds one or more arrays of female mould parts 38. The retaining unit in this embodiment holds a pairs of arrays of mould parts arranged in a side-by-side arrangement as described above, as does the picker 20.

The picker 20 is moved into a position of alignment such that the protrusions 28 are substantially coaxial with the openings in the alignment member 50. The picker is then moved towards the retaining unit 40 such that the male mould parts are inserted part way into the corresponding female mould parts as shown in figure 6. The male and female mould parts within their respective arrays are thus brought into close proximate alignment. However it is to be noted that in this embodiment, the male and female mould parts are not brought into contact so as to form the complete lens mould at this stage.

When the male and female mould parts are aligned, the grippers are operated to grip onto the radial arms of the sprue 54 joining the female mould parts 38. At this point the negative pressure applied to the suction cups 46 may be halted. The picker 20 then retracts from the retaining unit with the male mould parts held on protrusions 28 and the female mould parts held in alignment with the male mould parts by the grippers 32 as is shown in figure 7.

The picker now holds the male and female parts in the correct alignment for formation of the complete lens mould and can move the assembled mould parts in unison as required without the risk of misalignment. One advantage of this system is that the sprue, which is typically considered to be waste material, can be used as a support for holding the array of female mould parts.

Turning now to figures 8 and 9, there is shown a heating apparatus in accordance with the third aspect of the present invention. Once assembled for use, it is required that the male and female mould parts are fused together to form a unitary mould for a lens. This is conventionally achieved using a heating assembly.

The heating apparatus 60 shown in figure 8 comprises a plurality of heating elements 62 mounted in a predetermined array on a support 64. The support 64 is planar in form and generally disc shaped. The support has a first set of apertures 66 spaced about its periphery for attachment of the support 64 to actuation means (not shown) such as a robot or else a ram arranged to move the heating apparatus 60 between a first position in which the apparatus 60 is spaced from a mould assembly and a second position in which the heating elements 62 contact the mould assembly.

The support may be attached to the actuation means by insertion of connection members through the apertures 66 and application of a removable fastening means such as, for example a C-clip or other snap fit or clip fit means. Thus the heating apparatus is easily attached to and removed from the actuation means.

The heating elements are arranged about the support member so as to correspond to the arrays of mould parts described above. In particular the heating elements are arranged to contact the rim portion of the assembled mould at multiple points about the periphery of the mould. In this embodiment, three heating elements 62 are arranged to contact the rim of each mould within the six-mould array simultaneously. Thus the heating apparatus comprises eighteen heating elements.

The heating elements comprise a resistive wire which is bent to form a pair of arms 68 and 70 which are obliquely angled so as to form an apex 72. Each arm 68 and 70 is held relative to the support 64 by insulating contact members 74 which are seated in correspondingly shaped ports within the support. The resistive wires are connected up to an electrical power source (not shown) which applies a voltage to the resistive wires during use.

The support comprises further openings 76 between each set of heating elements in the vicinity of the mould to be welded.

During use the array of assembled male and female mould parts is moved into contact with the heating elements 62 such that heat is conducted to the rim of either the male or female mould part dependent on the orientation of the mould relative to the heating apparatus. The applied heat is sufficient to melt the portion of the rim in the vicinity of the heating element 62 so as cause adhesion to the rim of the adjacent mould part. The array of moulds is then moved away from the heating apparatus such that the male and female mould parts are resiliently adhered during cooling.

The inverted V-shape of the heating elements 62 is important in controlling the degree of contact between the heating elements and the plastic mould. In addition the angled nature of the heating elements serves to reduce the amount of molten material which is retained on the heating element as a residue when the mould is moved away.

Turning now to figures 10 and 11, there is shown a tray 80 for holding assembled moulds comprising the male 12 and female 38 mould parts described above. Once the mould parts have been aligned as described in relation to figures 5 to 7, the mould assemblies are vulnerable to misalignment once they are put down by the picker 20 and at subsequent stages in the manufacture of lenses until the male and female mould parts are welded as described above in relation to figures 8 and 9.

In view of this fact, the Applicant has developed a customised tray structure for holding the assembled moulds. The tray has a plurality of recesses 82 which are shaped to receive an array of assembled moulds, The recesses 82 comprise side walls which are formed of a series of curved portions 84 spaced by intermediate adjoining wall portions 86. The curved wall portions are shaped in plan to follow the arc of a circle and may be substantially semicircular.

The curved wall portions 84 are shaped to closely contact an outward-facing edge of the female mould parts with in each array. Thus the assembled arrays are restrained from lateral movement in multiple directions once placed in the recess 82 of the tray.

A plurality of recesses 82 are provided in each tray, which may be arranged in rows. In this embodiment, a total of thirty-six recesses are provided in six rows allowing the tray to accommodate thirty-six arrays of moulds, or two hundred and sixteen moulds in total.

Along one or more edges of the tray 80, there are provided raised projections 88 which depend inwardly from the peripheral rim of the tray. The projection are generally tongue shaped in plan and prevent unwanted nesting of the trays when stacked.

The assembled male and female mould parts may be placed in the recesses in an alignment as shown in figure 6 by inserting the female mould part into the recess and then releasing the grippers 32 and shutting off the negative pressure to ports 30 in the projections 28. Thus the male mould parts are dropped a short distance into contact with the inner surface of the female mould parts. This drop of a short distance has been found to reliably bring the male and female mould parts into contact without misalignment or adverse impact forces.

As an alternative to the plastic trays of figures 10 and 11, the assembled moulds may be positioned in conventional flat metal oven trays which have arrays of apertures therein for receipt of the assembled moulds. It has also been found that the mould assemblies can be stacked within either embodiment of tray without substantial loss of alignment of the mould parts.

Once positioned in the trays, the assembled moulds can be moved to different stations for further manufacturing steps in the production of the lenses such as for curing, filling P02874UK 20080808 SpecAsFiled.doc or the like.

Whilst the above embodiments are arranged to handle mould parts in multiples of six arranged in a generally circular array, it will be appreciated that each of the first, second and third retaining means, the heating elements and/or the recesses in the tray could be adapted to handle varying numbers of mould parts in various configurations or shapes' of array. In any such embodiment, the retaining formations on each of the first, second and third retaining means should be provided in orientations and/or spacings which match that of the other retaining means.

Claims

Claims: 1. A mould assembly system comprising: first retaining means having a plurality of formations for releasably retaining an array of first mould parts; second retaining means having a plurality of formations for releasably retaining an array of second mould parts; the first and second retaining means being arranged for relative movement therebetween so as to bring the first and second arrays into proximate alignment for assembly of an array of moulds; wherein the second retaining means comprises gripping means for gripping the array of first mould parts such that the proximate alignment of said arrays of first and second moulded parts is maintained upon subsequent relative movement between the first and second retaining means.
2. A mould assembly system according to claim 1, wherein the first and second mould parts form a lens mould once assembled.
3. A mould assembly system according to claim 1 or 2, wherein the first retaining means comprises an array of alignment formations for presenting the first mould parts for alignment with the second mould parts.
4. A mould assembly system according to claim 3, wherein the alignment formations comprise apertures in which the array of first mould parts may be located, the apertures being oriented in an array which corresponds to the orientation of the array of second mould parts held by the second retaining means.
5. A mould assembly system according to claim 3 or 4, wherein the first retaining means further comprises an array of suction cups positioned relative to the alignment formations and arranged to releasable hold the first mould parts located within the alignment formations.
6. A mould assembly system according to any preceding claim, in which the first and second mould parts are arranged in a circular array.
7. A mould assembly system according to claim 6, wherein the retaining formations of the first and second retaining means are arranged in a corresponding array.
8. A mould assembly system according to c'aim 6 or 7, wherein the first mould parts have spacer members which connect the first mould parts within an array whereas the array of second mould parts are not connected by spacer members.
9. A mould assembly system according to any preceding claim, wherein the second retaining means comprises a plurality of protrusions shaped to receive the second mould parts thereon, each protrusion having an opening therein for application of fluid pressure to a mould part located on the protrusion.
10. A mould assembly system according to any preceding claim, wherein the gripping iS means comprises opposing gripper members in the form first and second fingers which are pivotably mounted and actuable between open and closed positions.
11. A mould assembly system according to claim 10, wherein the gripper means comprises a plurality of spaced grippers mounted at different angular orientations within or amongst the array of protrusions.
12. A mould assembly system according to claim 10 or 11, wherein grippers are arranged to grip one or more spacer members of the array of first mould parts during use.
13. A mould assembly system according to any preceding claim, further comprises a third retaining means for releasably retaining the array of second mould parts prior to pick up by the second retaining means.
14. A mould assembly system according to claim 13, wherein the third retaining means comprises an array of cup formations in which the second mould parts arelocatable.
15. A mould assembly system according to any preceding claim, wherein the gripping means is arranged to grip the array of first mould parts a small distance from the final intended resting condition of the first and second mould parts once assembled to form a mould.
16. A mould assembly system according to any preceding claim, wherein any or any combination of the first or second retaining means comprises actuation means for effecting controlled relative movement between the first and second retaining means.
17. A mould assembly system according to any preceding claim, further comprising a tray arranged to receive the assembled array of first and second mould parts, the tray having one or more recesses therein, each recess having a peripheral wall shaped to closely surround the array of mould parts.
18. A mould assembly system according to claim 17, wherein the peripheral wall is multiply curved so as to maintain contact with a portion of each of the body portions of the first mould parts in the array.
19. A method of manufacturing a mould assembly comprising: providing an array of first mould parts and an array of second mould parts; releasably retaining the array of first mould parts in first retaining means; releasably retaining the array of second mould parts in second retaining means; moving the second retaining means towards the first retaining means so as to bring the first and second arrays into proximate alignment for assembly of an array of moulds; wherein the second retaining means comprises gripping means for gripping the array of first mould parts such that the proximate alignment of said arrays of first and second moulded parts is maintained upon subsequent relative movement between the first and second retaining means.
20. Apparatus for assembly of first and second lens mould parts to form a lens mould, the apparatus comprising: a support member; and.a plurality of conductive heater elements depending from the support member, the heater elements comprising a first arm depending from the support member at a first location and a second arm depending from the support member at a second location spaced from the first location, wherein the first and second arms are at least in part obliquely angled so as to form an apex for contact with one mould part so as to thereby heat the mould part for adhesion to the other mould part.
21. Apparatus according to claim 20, wherein the heater element are formed of a unitary piece of resistive material which is shaped to form a heater element which is V-shaped in part.
22. Apparatus according to claim 20 or 21, wherein the support member is releasably attachable to a holder using quick release means comprising a clip.