Method and apparatus related to manufacturing semi-mold for forming contact lens

Abstract

An apparatus (60) for injection molding mold halves (2, 4) for use in manufacturing contact lenses includes one or more first tool halves (22) mounted on a first support (80) and one or more second tool halves (24) releasably mounted on a second support (82). With the second support (82) in an operative orientation, the first support (80) and the second support (82) are movable between a closed position in which the first tool half (22) and the second tool half (24) engage with each other to provide a corresponding mold cavity (54) therebetween, and an open position in which the first tool half (22) and the second tool half (24) engage with each other to provide a corresponding mold cavity (54) therebetween. The first tool half (22) and the second tool half (24) are aligned with each other across a portion removal gap (86). The second support (82) is movable between the operative orientation and a reloading orientation in which the second tool half (24) is located in a tool change area (64) that is misaligned with the first tool half (22).

Description

Technical Field

[0001] The present disclosure relates to the field of contact lens manufacturing using mold halves produced by injection molding. In particular, the present disclosure relates to apparatus and methods for quickly inspecting, replacing or exchanging tools in an injection molding machine for manufacturing the mold halves. Background Art

[0002] Various methods of manufacturing contact lenses are known, including spin casting, lathing (for example, by diamond turning), and cast molding (for example, using injection molded mold halves). In particular, cast molding of contact lenses involves: forming a pair of mold halves (i.e., a first mold half and a second mold half); placing a volume of contact lens formulation on an optical quality surface of one of the two mold halves; and placing the two mold halves in contact with each other to form a contact lens mold assembly having a contact lens-shaped cavity containing the contact lens formulation. The contact lens mold assembly is then exposed to conditions that cause the contact lens formulation to polymerize or cure in the contact lens mold assembly. With the use of high-speed manufacturing lines, extremely large numbers (for example, tens of thousands per day) of contact lenses can be manufactured. Increases in the manufacturing rate of contact lenses are expected to reduce the cost of each lens. However, it is important that the increase in manufacturing rate not compromise the quality of the lenses produced.

[0003] When a contact lens is formed by cast molding using an injection molded contact lens mold half, the process includes a number of steps. For example, the process of creating a mold half may include: closing two injection molding tool halves disposed in a plate of an injection molding machine; forming a contact lens mold half in the closed injection molding tool half; opening the tool half containing the injection molded mold half; removing the injection molded mold half from the opened tool half; and optionally transferring the newly formed mold half to a conveyor for further processing. As understood by those skilled in the art and as used herein, an injection molding tool half refers to an insert (usually metallic) used to form a curved surface of a contact lens mold half. The insert is typically disposed in a plate of an injection molding machine. One or both of the inserts or the tool half will have an optical quality surface for forming a lens-forming surface of the contact lens mold half.

[0004] The mold halves, and in particular their optical surfaces, must be produced with high manufacturing tolerances. As a result, tool halves used to mold optical surfaces are typically subject to frequent inspection and are replaced or repaired at the first sign of wear or damage. In addition, the same injection molding machine is typically used to produce a series of mold halves, each of which produces a contact lens of a corresponding shape (and therefore corresponding optical properties). Conventionally, tool halves are replaced by interrupting use of the injection molding machine, switching tool halves (for example, using a robotic arm), and then resuming use of the machine. The machine downtime required to switch tools can greatly increase the overall production cost of the mold halves and, therefore, the contact lenses produced with the mold halves.

[0005] The object of the present invention is to mitigate or eliminate one of the above-mentioned disadvantages and / or to provide an improved or alternative apparatus or part of an apparatus for injection moulding a mould half, a method for injection moulding a mould half, a mould half for manufacturing a contact lens, a method for manufacturing a contact lens or a contact lens. Summary of the invention

[0006] According to a first aspect of the present disclosure, there is provided an apparatus for injection molding a mold half for use in manufacturing a contact lens, the apparatus comprising one or more first tool halves mounted on a first support and one or more second tool halves releasably mounted on a second support. With the second support in an operating orientation, the first support and the second support are movable between a closed position, in which the first tool half and the second tool half engage with each other to provide a corresponding mold cavity therebetween, and an open position, in which the first tool half and the second tool half are aligned with each other across a partial removal gap. The second support is movable between the operating orientation and a reloading orientation, in which the second tool half is located in a tool change region that is not aligned with the first tool half.

[0007] According to a second aspect of the present disclosure, a portion of the device according to the first aspect of the present disclosure is provided, the portion comprising a first support, a second support and a drive mechanism for moving the first support and the second support between an open position and a closed position and moving the second support between the orientations.

[0008] According to a third aspect of the present disclosure, a method for injection molding a mold half for use in manufacturing contact lenses is provided. The method includes: moving a second support to an operating orientation; and then moving a first support and a second support to a closed position so that one or more first tool halves supported on the first support and one or more second tool halves releasably supported on the second support engage with each other to provide a corresponding mold cavity therebetween. The method further includes: injecting a molten polymer into the mold cavity, and then allowing the polymer to solidify in the mold cavity and form a mold half. In addition, the method includes: moving the first support and the second support to an open position so that the first tool half and the second tool half are aligned with each other across a partial removal gap. The method also includes removing the mold half through the partial removal gap. In addition, the method includes: moving the second support to a reloading orientation, in which the second tool half is located in a tool change area that is not aligned with the first tool half. The method further includes: removing the second tool half from the second support.

[0009] According to a fourth aspect of the present disclosure, a half mold for manufacturing a contact lens is provided, which is injection molded using the apparatus of the first aspect of the present disclosure and / or the method of the third aspect of the present disclosure.

[0010] According to a fifth aspect of the present disclosure, a method for manufacturing a contact lens is provided. The method comprises: injection molding a male mold half and injection molding a female mold half, at least one of the mold halves being the mold half according to the fourth aspect of the present disclosure. The method further comprises: engaging the male mold half and the female mold half with each other, wherein a certain amount of contact lens formulation is located in a cavity defined therebetween. The method further comprises: curing the contact lens formulation to form the contact lens. The method further comprises: separating the male mold half from the female mold half and removing the contact lens.

[0011] According to a sixth aspect of the present disclosure, there is provided a contact lens manufactured using the method of the fifth aspect of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A and 1B are perspective and cross-sectional views of two mold halves for use in producing contact lenses.

[0013] Figure 2A and 2B yes Figure 1A and 1B Perspective and cross-sectional views of two mold halves engaged with each other to define a cavity therebetween.

[0014] Figure 3 is used to generate Figures 1A to 2B Cross-sectional view of a pair of tool halves of a male die half.

[0015] Figure 4 is used to generate Figures 1A to 2B Cross-sectional view of a pair of tool halves of a female mold half.

[0016] Figure 5 Is used for Figure 3 and 4 The multiple pairs of tool halves shown in Figures 1A to 2B A perspective view of an apparatus for performing injection molding of a mold half.

[0017] Figure 6 yes Figure 5 A perspective view of the device with the partition removed.

[0018] Figure 7 yes Figure 5 and 6 A cross-sectional view of a first support member and a second support member of a device. DETAILED DESCRIPTION

[0019] According to a first aspect of the present disclosure, there is provided an apparatus for injection molding a mold half for use in manufacturing a contact lens, the apparatus comprising one or more first tool halves mounted on a first support and one or more second tool halves releasably mounted on a second support, wherein:

[0020] the first and second supports being movable between a closed position in which the first and second tool halves engage one another to provide corresponding mold cavities therebetween and an open position in which the first and second tool halves are aligned with one another across a partial removal gap with the second support in the operative orientation; and

[0021] The second support is movable between the operating orientation and a reloading orientation in which the second tool half is located in a tool change area out of alignment with the first tool half.

[0022] The second support is movable between the operating orientation and the reloading orientation, whereby moving the second tool half between alignment with and misalignment with the first tool half in the tool change area may allow the second tool half to be easily removed from and / or attached to the second support. For example, the tool change area may be a location more easily accessible to a worker or robot tasked with removing the second tool half from the second support (e.g., for inspection, repair, or replacement) and / or attaching the second tool half to the second support (e.g., after the inspection, repair, or replacement). For a given number of mold halves, such easy access may translate into reduced downtime, and thus lower overall costs incurred.

[0023] For the avoidance of doubt, reference to the first and second supports moving between an open position and a closed position refers to the first and second supports moving relative to each other. Thus, when moving between positions, the first support may move relative to a fixed second support, the second support may move relative to a fixed first support, or both the first and second supports may move. Embodiments in which the second support remains fixed while the first and second supports move between positions may be beneficial because the mechanism required may be simpler than where the second plate must be movable between the orientations and also movable to move the supports between positions.

[0024] The support is movable along a vertical axis between the open position and the closed position.

[0025] This may, for example, reduce the "footprint" of the apparatus (i.e., the floor space occupied by the apparatus) compared to an arrangement in which the support moves along a horizontal axis between positions. Alternatively or as well, it may allow gravity to assist in removing the second tool half from the second support and / or attaching the second tool half to the second support.

[0026] The apparatus may further include one or more third tool halves releasably mounted on the second support, wherein with the second support in the reloading orientation, the first support and the second support are movable between another closed position in which the first tool half and the third tool half engage with each other to provide corresponding mold cavities therebetween and another open position in which the first tool half and the third tool half are aligned with each other across a partial removal gap.

[0027] This may allow the apparatus to continue injection molding the mold halves using the first and third tool halves while the second tool half is in the tool change area (eg removed from or attached to the second support).

[0028] Alternatively, the apparatus may include no tool halves other than the first and second tool halves. In such an arrangement, a clear area of ​​the second support may be aligned with the first tool half when the second support is in the reloading orientation. Such a clear area may further be located in the tool change area when the second support is in the operating orientation.

[0029] Where the apparatus comprises a third tool half, the third tool half may have substantially the same shape as the second tool half (so that a mold half produced using the first and second tool halves will have substantially the same shape as a mold half produced using the first and third mold halves), or may have a different shape than the second tool half (so that a mold half produced using the first and second tool halves will have a different shape than a mold half produced using the first and third mold halves).

[0030] With the second support element in the operating orientation, the third tool half can be located in the tool change area.

[0031] This can allow the machine to continue injection molding the mold half using the first and second tool halves while the third tool half is in the tool change area (e.g., removed from or attached to the second support). In other words, the machine can operate using the first and second tool halves while the third tool half is removed or attached, and can also operate using the first and third tool halves while the second tool half is removed or attached.

[0032] Alternatively, with the second support in the operating orientation, the third tool half can be located outside the tool change area, for example in an intermediate position between the tool change area and the position in which the third tool half is to be aligned with the first tool half. In this arrangement, the second support can be moved to another orientation in which the third tool half is located in the tool change area.

[0033] The apparatus may further include one or more fourth tool halves releasably supported on the second support.

[0034] This may improve the versatility of the apparatus. For example, where the second, third and fourth tool halves have mutually different shapes, the apparatus may be able to produce three differently shaped mould halves simply by moving the support between orientations.

[0035] The fourth mold half can also be located in the tool change area when the second support is in the operating orientation. Thus, while the first and second tool halves are used to produce the mold half, the fourth tool half can be accessed in a manner similar to that discussed above with respect to the third tool half.

[0036] By moving the support along the molding axis (the molding axis can be understood to refer to the axis along which the mold halves move to contact each other to form the mold assembly), the support can be moved between the open position and the closed position, and the second support can be moved between the operating orientation and the reloading orientation in a direction normal to the molding axis. For example, the second support can be rotated around an axis parallel to the molding axis between the operating orientation and the reloading orientation.

[0037] This may allow the mechanism for moving the second support between orientations to be advantageously simple and / or robust, compared to an arrangement in which the second support moves in a direction having a component parallel to the moulding axis (e.g. an arrangement in which the second support has a shape similar to an escalator with each "step" supporting a different set of tool halves).

[0038] The or each second tool half may be configured to form an optical surface of the mould half.

[0039] An optical surface provided on the second tool half (which, as described above, can advantageously be easily removed / attached) may be particularly beneficial because a tool half providing an optical surface may particularly need to be removed for inspection (because the optical surface forms the surface of a mold half which will then form the surface of a finished contact lens) or replaced by a different tool half (because different mold halves typically require different optical surfaces but may otherwise have the same shape).

[0040] The apparatus may further include one or more replacement tool halves configured to be releasably mounted on the second support to replace the second tool half.

[0041] An apparatus capable of using an alternative tool half in place of the second tool half may increase the versatility of the apparatus, allowing some mold halves to be produced using the first tool half and the second tool half (and / or the first tool half and the third tool half and / or the first tool half and the fourth tool half, where present), and different mold halves to be produced using the first tool half and the alternative tool half.

[0042] As an alternative, the apparatus may be configured to operate using only the first and second tool halves (and third and fourth tool halves, where present), with individual tool halves being removed and replaced for inspection or repair as necessary.

[0043] According to a second aspect of the present disclosure, a portion of the device according to the first aspect of the present disclosure is provided, the portion comprising a first support, a second support and a drive mechanism for moving the first support and the second support between an open position and a closed position and moving the second support between the orientations.

[0044] The portion may be used to manufacture an apparatus according to the first aspect of the present disclosure, thereby providing one or more of the benefits discussed above.

[0045] The drive mechanism may comprise an electric, hydraulic or pneumatic motor. Such a motor may be arranged to move the second support between said orientations. Where the drive mechanism comprises such a motor, it may further comprise a transmission device driven by that motor, such as a chain drive, belt drive or gearbox.

[0046] Alternatively or as well, the drive mechanism may include a pneumatic cylinder, a hydraulic cylinder, a solenoid and / or an electric linear actuator. The drive mechanism may include more than one of the components, such as two, three, four or more. The one or more components may be arranged to move the first plate and the second plate between the open position and the closed position.

[0047] According to a third aspect of the present disclosure, there is provided a method of injection molding a mold half for use in manufacturing a contact lens, the method comprising:

[0048] moving the second support to an operative orientation, and then moving the first support and the second support to a closed position such that one or more first tool halves supported on the first support and one or more second tool halves releasably supported on the second support engage one another to provide corresponding mold cavities therebetween;

[0049] injecting a molten polymer or molten plastic into the mold cavity and then allowing the polymer or plastic to solidify in the mold cavity and form a mold half;

[0050] moving the first support and the second support to an open position so that the first tool half and the second tool half are aligned with each other across a partial removal gap;

[0051] removing the mold half through the partial removal gap;

[0052] moving the second support member to a reloading orientation in which the second tool half is located in a tool change area out of alignment with the first tool half; and

[0053] The second tool half is removed from the second support.

[0054] Moving the second support between an operating orientation and a reloading orientation and thereby moving the second tool half between alignment with and out of alignment with the first tool half in the tool change area may allow the step of removing the second tool half and / or the step of (re)attaching the second tool half to be advantageously easier to perform. For example, the tool change area may be a location more easily accessible to a worker or a robot tasked with removing the second tool half (e.g. for inspection, repair or replacement) and / or (re)attaching the second tool half to the second support (e.g. after said inspection, repair or replacement). For a given number of mold halves, this easy access may translate into reduced downtime and, therefore, lower overall costs incurred.

[0055] The method may use the apparatus according to the first aspect of the present disclosure.

[0056] Moving the support to the closed position and moving the support to the open position may each include moving the support along a vertical axis.

[0057] For example, first and second supports movable along a vertical axis may reduce the "footprint" of the apparatus (and, the floor space occupied by the apparatus) compared to an arrangement in which the supports move along a horizontal axis between positions. Alternatively or as well, it may allow gravity to assist in removing the second tool half from the second support and / or attaching the second tool half to the second support.

[0058] The step of moving the second support to the reloading orientation may also move one or more third tool halves also releasably supported by the second support into alignment with the first tool half, and the method may further include:

[0059] moving the first support and the second support to another closed position, wherein the second support is in the reloading orientation, so that the first tool half and the third tool half engage each other to provide a corresponding mold cavity therebetween;

[0060] injecting a molten polymer or plastic into the mold cavity and then allowing the polymer or plastic to solidify in the mold cavity and form an additional mold half;

[0061] moving the first support and the second support to another open position so that the first tool half and the third tool half are aligned with each other across a partial removal gap; and

[0062] The additional mold half is removed through the partial removal gap.

[0063] This may allow the apparatus to continue injection molding the mold halves using the first and third tool halves while the second tool half is in the tool change area (eg removed from or attached to the second support).

[0064] Alternatively, the apparatus may include no tool halves other than the first and second tool halves. In such an arrangement, moving the second support to the reloading orientation may move a blank area of ​​the second support into alignment with the first tool half. Such a blank area may further be moved to a tool change area when the second support is moved to the operating orientation.

[0065] Moving the second support member into the operative orientation also allows the third tool half to be moved into the tool change area.

[0066] This can allow the machine to continue injection molding the mold half using the first and second tool halves while the third tool half is in the tool change area (e.g., removed from or attached to the second support). In other words, the machine can operate using the first and second tool halves while the third tool half is removed or attached, and can also operate using the first and third tool halves while the second tool half is removed or attached.

[0067] Alternatively, moving the second support member into the operating orientation may move the third tool half to a position outside the tool change area, for example in an intermediate position between the tool change area and a position in which the third tool half is to be aligned with the first tool half. Such a method may further comprise the step of moving the second support member into another orientation in which the third tool half is located in the tool change area.

[0068] The step of moving the second support into the operative orientation may also move one or more fourth tool halves, also releasably supported by the second support, into the tool change area.

[0069] This may improve the versatility of the apparatus. For example, where the second, third and fourth tool halves have mutually different shapes, the apparatus may be able to produce three differently shaped mould halves simply by moving the support between orientations.

[0070] The step of moving the second support to the operational orientation may also move the fourth mold half to the tool change area. Thus, while the mold half is being produced using the first and second tool halves, the fourth tool half may be accessed in a manner similar to that discussed above with respect to the third tool half.

[0071] Optionally:

[0072] Moving the first support and the second support to the closed position and moving the first support and the second support to the open position each include moving the first support and the second support along a molding axis; and

[0073] Moving the second support to the operating orientation and moving the second support to the reloading orientation each include moving the second support in a direction normal to the molding axis, for example rotating the second support about an axis parallel to (for example, colinear with) the molding axis.

[0074] This may allow the mechanism for moving the second support between orientations to be advantageously simple and / or robust, compared to an arrangement in which the second support moves in a direction having a component parallel to the moulding axis (e.g. an arrangement in which the second support has a shape similar to an escalator with each "step" supporting a different set of tool halves).

[0075] Optionally:

[0076] Moving the first support and the second support to the closed position and moving the first support and the second support to the open position each include moving the first support and the second support along a molding axis; and

[0077] Moving the second support to the operating orientation and moving the second support to the reloading orientation each include rotating the second support about an axis parallel to the molding axis.

[0078] The step of allowing the polymer or plastic to solidify in the mould cavity and form the mould half may include allowing some of the polymer or plastic to solidify against an optical surface provided by the second tool half so as to form the optical surface of the mould half.

[0079] An optical surface provided on the second tool half (which, as described above, can advantageously be easily removed / attached) may be particularly beneficial because a tool half providing an optical surface may particularly need to be removed for inspection (because the optical surface forms the surface of a mold half which will then form the surface of a finished contact lens) or replaced by a different tool half (because different mold halves typically require different optical surfaces but may otherwise have the same shape).

[0080] The method may further comprise attaching the second tool half to the second support, for example reinstalling a second tool half previously removed from the second support, or attaching a replacement of one or more of the second tool halves, for example in the event that the second tool halves have become worn or damaged. As an alternative, the method may further comprise the step of replacing the second tool halves removed from the second support with one or more replacement tool halves.

[0081] An apparatus capable of using an alternative tool half in place of the second tool half may increase the versatility of the apparatus, allowing some mold halves to be produced using the first tool half and the second tool half (and / or the first tool half and the third tool half and / or the first tool half and the fourth tool half, where present), and different mold halves to be produced using the first tool half and the alternative tool half.

[0082] As an alternative, the apparatus may be configured to operate using only the first and second tool halves (and third and fourth tool halves, where present), with individual tool halves being removed and replaced for inspection or repair as necessary.

[0083] According to a fourth aspect of the present disclosure, a half mold for manufacturing a contact lens is provided, which is injection molded using the apparatus of the first aspect of the present disclosure and / or the method of the second aspect of the present disclosure.

[0084] The mold halves so produced may be less expensive to produce, for example due to reduced downtime as discussed above.

[0085] According to a fifth aspect of the present disclosure, there is provided a method for manufacturing a contact lens, the method comprising:

[0086] injection molding a male mold half and injection molding a female mold half, at least one of the mold halves being the mold half according to the fourth aspect of the present disclosure;

[0087] engaging the male mold half and the female mold half with each other with a quantity of contact lens formulation located in a cavity defined therebetween;

[0088] curing the contact lens formulation to form the contact lens; and

[0089] The male mold half is separated from the female mold half and the contact lens is removed.

[0090] It is understood that curing of contact lens formulations occurs by polymerization.

[0091] For the reasons given above, the method using a mould half according to the fourth aspect of the present disclosure may reduce the costs associated with that mould half, thereby reducing the production costs of the contact lens.

[0092] The method may include additional steps, for example, washing or rinsing the contact lens and / or hydrating the contact lens.

[0093] According to a sixth aspect of the present disclosure, there is provided a contact lens manufactured using the method of the fifth aspect of the present disclosure.

[0094] For the reasons given above, such contact lenses may be cheaper to produce.

[0095] Those skilled in the art will appreciate that the incompatible specific features of the embodiments of the present disclosure described herein may be present in any combination in the exemplary embodiments of the present disclosure. Where appropriate, the optional or preferred features described in relation to one aspect of the present disclosure may be applicable to other aspects of the present disclosure.

[0096] Herein, reference is made to mold halves, but it should be understood that while two mold halves may complement each other and together form a mold assembly, each mold half is not necessarily half or 50% of the mold assembly. One mold half may include 20%, 30%, 40%, 45%, etc. of the mold assembly, while the other mold half may include 80%, 70%, 60%, 55%, etc. of the mold assembly. Thus, while two mold halves may make a complete mold assembly, it should be understood that the two mold halves do not have to be the same size or mirror images of each other. Similarly, while reference is made herein to tool halves, it should be understood that two tool halves that complement each other and together define a mold cavity do not have to be the same size or mirror images of each other.

[0097] Refer to the diagram, Figure 1A and 1B (as well as Figure 2A and 2B ) shows mold halves for use in manufacturing contact lenses, namely male mold half 2 and female mold half 4. Each mold half 2, 4 has an alignment tab 6, a rim portion 8, an optical surface 10 and a non-optical surface 12. The optical surface 10 of the male mold half 2 is convex and its non-optical surface 12 is concave, while the optical surface 10 of the female mold half 4 is concave and its non-optical surface 12 is convex.

[0098] like Figure 2A and 2B, the male mold half 2 and the female mold half 4 can engage with each other. With the mold halves 2, 4 so engaged, the mold halves 2, 4 are sealed to each other, and the convex optical surface 10 of the male mold half 2 protrudes into the concave optical surface 10 of the female mold half 4. The two optical surfaces 10 thus form a cavity 16 within which a contact lens can be molded.

[0099] To make a contact lens using the mold halves 2, 4, a quantity of contact lens formulation is placed in or on the concave optical surface 10 of the concave mold half 4, and the male mold half 2 and the female mold half 4 are engaged with each other. When the mold halves 2, 4 are engaged, the contact lens formulation expands and substantially fills the cavity 16. The mold halves 2, 4 containing the nano-contact lens formulation are then treated, for example, using heat or UV light, to cure the formulation into a polymer contact lens. The mold halves 2, 4 can then be separated to release the contact lens, which is then washed to remove any residual chemicals that do not form part of the polymerized contact lens, such as unreacted monomers, etc. The lens is then hydrated and packaged to be ready for use.

[0100] The mould halves 2, 4 are each produced by injection moulding into a cavity formed between a pair of tool halves. Figure 3 A pair 20 of tool halves are shown for producing a male mold half 2, and Figure 4 A pair 20 of tool halves is shown for producing the female mold half 4. Each pair comprises a first tool half 22 and a second tool half 24.

[0101] Each first tool half 22 includes an injection nozzle 26, a thermocouple 28, a tool portion 30, and an ejection mechanism (not visible) arranged to eject the formed mold half. A coolant flow channel (not visible) is provided behind the tool portion 30, passing approximately 4 mm from its outermost surface 32 at its closest point. The injection nozzle 26 and thermocouple 28 of the first tool half 22 are located away from the center of the tool portion 30. This leaves room for the coolant channel to pass close to the outer surface 32 of the tool portion 30, where the surface of the contact lens mold half for cast molding the optical zone of the contact lens is formed.

[0102] Each second tool half 24 of this example takes the form of a collet 40 carrying a tool insert 42. Each collet 40 has a front disk portion 43 and a frustoconical body portion 44. The frustoconical body portion 44 has a coolant passage 45 down its center, to the rear of the tool insert 42 and back, and includes an annular groove 46 toward its rear. As discussed in more detail later, each second tool half 24 can be supported on a second support. More specifically, in this example, each second tool half 24 can be supported in a corresponding bushing 48 of the second support. In this example, the bushing 48 also has a coolant passage 50 extending therearound.

[0103] The first tool half 22 can be clamped in place in the bushing 48 and thus attached to the second support by a separate clamp (not shown) which engages the recess 46 of the collet 40 to prevent the frustoconical body portion 44 from withdrawing from the bushing 48. Each second tool half 24 can be loosened, removed and replaced independently of the other second tool halves, enabling flexible exchange of the second tool halves 24. Furthermore, each collet 40 can carry a different tool insert 42.

[0104] The second tool half 24 of each pair 20 provides the optical surface 52. Figure 3 In the case of the second tool half 24, the optical surface 52 of the second tool half is concave and defines the convex optical surface 10 of the male mold half 2. Figure 4 In the case of the second tool half 24 of the embodiment of the present invention, the optical surface 52 of the second tool half is convex and defines the concave optical surface 10 of the concave mold half 4. In each case, in this example, the optical surface 52 of the second tool half 24 is arranged on the tool insert 42. Thus, by replacing the tool insert 42 of the second tool half 24, the shape of the optical surface 52 of the second tool half 24 and thus the shape of the optical surface 10 of the mold halves 2, 4 (and thus the shape and optical properties of the resulting contact lens) can be changed.

[0105] In the first tool half 22 of each pair 20, the outermost surface 32 of the tool portion 30 provides a surface that is complementary in shape to the optical surface 52 of the associated second tool half 24. Figure 3 The outermost surface 32 of the tool portion 30 of the first tool half 22 is convex, and Figure 4 The outermost surfaces 32 of the tool portion 30 of the first tool half 22 are concave. Since these surfaces do not form surfaces of the mold halves 2, 4 that will form the surfaces of the contact lens, their precise shape is less important. Thus, the same first tool half 22 can be used with a plurality of different second tool halves (e.g., where a plurality of different tool inserts 42 are assembled to the same chuck 40, and / or where different sets of chucks 40, each with a different tool insert 42).

[0106] Figure 3 and 4 Pairs 20 of tool halves 22, 24 are shown engaged with one another. So engaged, the first and second tool halves 22, 24 form a mold cavity 54 into which molten polymer or plastic may be injected (through injection nozzle 26) and allowed to cool to form the respective mold halves 2, 4.

[0107] Figure 5An example of an apparatus 60 for injection molding mold halves is shown, the apparatus utilizing the first tool half 22 and the second tool half 24 as described above. The apparatus comprises an injection molding area 62 and a tool change area 64 separated from each other by a partition 66 comprising a sliding door 68. The apparatus 60 also comprises a tool exchange robot 70, a tool storage magazine 72, and a take-out robot 74 having a plate 76. Furthermore, as shown in FIG. 6 , the apparatus comprises a first support 80 and a second support 82.

[0108] Figure 6 The apparatus 60 is shown with the divider 66 removed, more clearly showing the first support 80 and the second support 82, and Figure 7 A cross section of this region is shown. Mounted to the first support member 80 is Figure 3 and 4 A set of first tool halves 22 of the type shown in FIG. Mounted to the second support 82 is Figure 3 and 4 A set of second tool halves 24 of the type shown in FIG. 1, as discussed below. In this particular example, the first support member 80 has Figure 3 Four first tool halves 22 of the type shown in FIG. Figure 4 Similarly, the second support member 82 has Figure 3 Four second tool halves 24 of the type shown in FIG. Figure 4 The first support 80 and the second support 82 hold the first tool half 22 and the second tool half 24 in the respective mounting plate assembly 84 . Figures 5 to 7 The same component numbers in the drawings refer to the same components described in this document.

[0109] Figures 5 to 7 The second support 82 is shown in an operational orientation. With the second support 82 in this orientation, the first support 80 and the second support 82 can be in an open position (eg, Figures 5 to 7 With the supports 80, 82 in the open position, the first tool half 22 and the second tool half 24 are aligned with each other across the partially removed gap 86. With the supports 80, 82 in the closed position, the aligned first tool half 22 and the second tool half 24 are aligned with each other across the partially removed gap 86. Figure 3 and 4 The methods shown in the figure mesh with each other.

[0110] In this example, the supports 80, 82 are movable between an open position and a closed position by moving the first support 80 along a vertically aligned molding axis 88 guided by a set of guide rods 89 extending parallel to the molding axis 88. The first support is mounted on a fixed feed unit 90, which also supports a hopper 92 containing polymer or plastic pellets to be injection molded by a pair of hydraulic cylinders 94 of the drive mechanism of the apparatus. To move the first support 80 to the closed position, the cylinders 94 are extended to lower the first support 80 downwardly along the molding axis 88 toward the second support 82, and to move the first support 80 to the open position, the cylinders 94 are retracted to lift the first support 80 upwardly along the molding axis 88 away from the second support 82.

[0111] In this example, the second support 82 also has a set of third tool halves 96 removably mounted in another mounting plate assembly 84a. The third tool halves 96 are substantially identical to the first tool halves 22, except that the tool inserts 42 have a slightly different shape so that the mold halves 2, 4 produced therefrom also have slightly different shapes. Therefore, the contact lenses produced using those mold halves 2, 4 will also have slightly different shapes, and therefore have slightly different optical properties. As illustrated, with the second support 82 in the operative orientation, the third tool halves are located in the tool change area.

[0112] The second support 82 is movable between an operating orientation and a reloading orientation. More specifically, in this example, the second support forms a turntable that can be rotated by an electric motor (not visible) of a drive mechanism of the apparatus 60. The second support 82 can rotate about an axis 98, which in this example is parallel to the molding axis 88. When the second support 82 rotates, the sliding door 68 in the divider 66 can be lifted, thereby providing sufficient clearance for the plate assembly 84 to pass under the divider 66.

[0113] With the second support 82 in the reloading orientation, the second tool half 24 is located in the tool change area, i.e., not aligned with the first tool half 22, and the third tool half 96 is located in the injection molding area 62, aligned with the first tool half 22. The second tool half 24 located in the tool change area 64 makes it easier to access. In this example, the tool change robot 70 is configured to remove the second tool half 24 from the second support 82 and place the second tool half 24 in the tool storage magazine 72, and then replace the second tool half 24 with a set of replacement tool halves 99 previously stored in the tool storage magazine 72. However, in other examples, replacement tool halves 99 may not be provided, and the tool change robot may remove one second tool half 24 at a time, for example, to inspect or replace its tool insert before reattaching the second tool half 24 to the second support 82.

[0114] Just as moving the second support 82 from the operating orientation to the reloading orientation moves the second tool half 24 from being aligned with the first tool half 22 to being out of alignment with the first tool half in the tool change area 64, it also moves the third tool half 96 from the tool change area to being aligned with the first tool half 22 in the injection molding area 62. With the second support 82 in this position, the first and second supports 80, 82 can be moved between another open position in which the first and third tool halves 22, 96 are aligned with each other across a partial removal gap, and a closed position in which the first and third tool halves 22, 96 engage each other in the same manner as described above with respect to the first and second tool halves 22, 24.

[0115] Thus, with the second support 82 in the reloading orientation, the apparatus 60 can continue to make mold halves 2, 4 while the second tool half 24 is removed for inspection or replacement. Thus, the only machine downtime required to inspect / replace the second tool half 24 is the time it takes the drive mechanism of the apparatus 60 to rotate the second support 82 from the operating orientation to the reloading orientation (which is approximately 4 seconds in this example).

[0116] In a corresponding manner, when the second support 82 is in the operating orientation, ie the second tool half 24 is aligned with the first tool half 22 in the injection molding area and the third tool half 96 is in the tool change area 64 , the tool exchange robot 70 can remove the third tool half 96 for inspection or replacement.

[0117] To injection mold the mold halves 2, 4, the second support 82 is moved to an operating orientation and the first and second supports 80, 82 are moved to a closed position so that the first and second tool halves 22, 24 define the mold cavity 54 as described above. The polymer or plastic pellets from the hopper 92 are heated above their melting point and the resulting liquid polymer / plastic flows into the manifold (not visible) and then through the injection nozzle 26 of the first tool half 22 into the cavity 54 (see FIG. Figure 3 and 4 ). Further heating is provided by a coil (not visible) surrounding each injection nozzle 26. A thermocouple 28 disposed on the side of the first tool half 22 opposite the injection nozzle 26 is used to monitor the temperature of the injected polymer / plastic. The heating of the nozzle 26 is controlled to ensure that the liquid polymer / plastic is injected into each of the eight cavities 54 at the same temperature and therefore at the same flow rate. Non-constant flow rates result in stresses in the formed mold, which in turn result in deformations and inconsistencies in the contact lenses formed by the mold, such as different fits, different radii, and therefore different magnifications. Careful control of pressure and cooling can achieve consistency and uniformity; in contrast, poor control can result in the need to selectively stop injection into cavities where the flow rate has deviated too far from the target value.

[0118] Once the cavity 54 is filled with polymer or plastic and the desired holding pressure profile is applied, a stop pin (not shown) in the injection nozzle 26 is moved forward to shut off the injection nozzle 26 from the cavity 54, which stops the flow of polymer / plastic. A coolant (e.g., water) is circulated through the coolant passages 45, 50 to cool the polymer / plastic and thereby form the mold halves, wherein the polymer / plastic solidifies against the optical surface 52 of the tool insert 42 and forms the optical surface 10 of the mold halves 2, 4. The coolant passages 45, 50 in the tool halves 22, 24 pass close to the outermost surface 32 of the tool portion and the optical surface 52 of the tool insert 42. This arrangement provides direct cooling in the portion of the mold halves 2, 4 that forms the optical zone of the lens as the mold halves 2, 4 are formed in the cavity (rapid cooling of the nucleated material results in a good quality, uniform mold; without nucleation, this results in slower cooling of the middle of the material, thereby forming larger crystals in the middle of the material).

[0119] Once the polymer / plastic has solidified and the mold halves 2, 4 have been formed, the hydraulic cylinder 94 lifts the first support 80 to move the supports 80, 82 to the open position, thereby separating the die halves 22, 24 and opening the cavity 54. As the first support 80 is lifted, the newly formed mold halves 2, 4 remain on the first tool half 22. The take-out robot 74 then inserts the plate 76 into the partial removal gap 86. The ejector mechanism (not visible) then pushes the mold halves 2, 4 away from the first tool half 22 so that the first tool half 22 can be collected onto the plate 76 using a high airflow vacuum. The take-out robot 74 then transports the mold halves 2, 4 on the plate through the partial removal gap 86 and away from the injection molding area 62 for further processing (e.g., further cooling, quality inspection, or immediate use in the manufacture of contact lenses as described above).

[0120] The above process may be followed to make additional mold halves 2, 4. Whenever the second tool half 24 needs to be inspected or replaced, or when it is desired to make a mold half 2, 4 of the shape to be produced by the third tool half 96, the second support 82 is moved to the reloading orientation so that the second tool half 24 is placed in the tool change area 64 and the third tool half 96 is aligned with the first tool half 22. The tool exchange robot 70 may then remove the second tool half 24 or replace the second tool half 24 with a replacement tool half 99 as described above. While this is happening, the apparatus may continue to injection mold additional mold halves 2, 4 using the first tool half 22 and the third tool half 96, moving the support 80, 82 between a further open position and a further closed position using the same process described above.

[0121] Similarly, whenever the third tool half 96 needs to be inspected or replaced, or when it is desired to manufacture a mold half 2, 4 of a shape to be produced by the first tool half 24 (or an alternative tool half 99, where the alternative tool half 99 has been placed on the second support 82), the second support 82 is moved to an operative orientation so as to place the third tool half 96 in the tool change area 64 and to place the second tool half 24 (or the alternative tool half 99) in alignment with the first tool half 22.

[0122] In this example, the production monitoring software logs each time a set of tool halves 24, 96 used in conjunction with the first tool half 22 to manufacture a mold half 2, 4 is replaced by changing the orientation of the second support 82. By doing so, the output of mold halves 2, 4 from the apparatus 60 can be managed autonomously. This can avoid the need to physically isolate different batches of mold halves 2, 4 produced using different sets of mold halves 24, 96 (e.g., packaging the mold halves into different containers for future processing).

[0123] While the present disclosure has been described and illustrated with reference to a particular embodiment, those skilled in the art will appreciate that the present disclosure lends itself to many different variations not specifically illustrated herein. By way of example only, in a modification of the apparatus described above, the second support may include a set of fourth tool halves as well as the second and third tool halves. In this example, the divider may be shaped so that with the second support oriented so that any one of the set of tool halves is aligned with the first tool half, one or both of the other sets of tool halves on the second support may be located in the tool change area. As another example, while the above examples have two different types of first tool halves, two different types of second tool halves, etc., other arrangements may have first tool halves that are completely identical to one another and second tool halves that are completely identical to one another (thus requiring tool conversion before both male and female mold halves can be produced). As an alternative, other examples may have four different types of first tool halves, four different types of second tool halves, etc., so that multiple sets of mold halves for two different shapes of contact lenses may be produced at once.

[0124] For the avoidance of doubt, the designations "first tool half", "second tool half", etc., should not be construed as having any limitations beyond those recited in the appended claims. No intention is given as to the structure or order of use of the tool halves. For example, in some examples, the second tool half and the third tool half may be equivalent to one another, and / or the first use of the apparatus may utilize the third tool half before the second tool half. Furthermore, it should be understood that although the apparatus described above has eight first tool halves mounted on a first support (and eight second tool halves and eight third tool halves mounted on a second support), this should not be construed as limiting. In modifications of the apparatus, there may be less than eight (e.g., one, two, or four) first tool halves mounted on a first support, or there may be more than eight first tool halves mounted on a first support, with a corresponding number of second tool halves (and a corresponding number of third tool halves, if applicable) mounted on a second support.

[0125] In the foregoing description, where reference is made to an integral body or element with a known, obvious or foreseeable equivalent, such equivalent is incorporated herein as if stated separately. Reference should be made to the claims to determine the true scope of the present disclosure, and the present disclosure should be interpreted as encompassing any such equivalent. The reader should also understand that integral bodies or features of the present disclosure described as preferred, advantageous, convenient, etc. are optional and do not limit the scope of the independent claims. In addition, it should be understood that such optional integral bodies or features, while beneficial in some embodiments of the present disclosure, may not be desirable in other embodiments and therefore may not exist.

Claims

1. An apparatus for injection molding a contact lens mold half for use in manufacturing a contact lens, the apparatus comprising one or more first tool halves mounted on a first support and one or more second tool halves releasably mounted on a second support, wherein: the first and second supports being movable between a closed position in which the first and second tool halves engage one another to provide corresponding mold cavities therebetween and an open position in which the first and second tool halves are aligned with one another across a partial removal gap with the second support in the operative orientation; and The second support is movable between the operating orientation and a reloading orientation in which the second tool half is located in a tool change area out of alignment with the first tool half.

2. The apparatus of claim 1, wherein the first support and the second support are movable along a vertical axis between the open position and the closed position.

3. The apparatus according to claim 1 or 2, further comprising one or more third tool halves releasably mounted on the second support, wherein the first support and the second support are movable between another closed position and another open position when the second support is in the reloading orientation, wherein in the another closed position, the first tool half and the third tool half engage with each other to provide corresponding mold cavities therebetween, and in the another open position, the first tool half and the third tool half are aligned with each other across a partial removal gap.

4. The apparatus of claim 3, wherein the third tool half is located in the tool change area with the second support in the operative orientation.

5. Apparatus according to claim 3 or 4, further comprising one or more fourth tool halves releasably supported on the second support.

6. An apparatus according to any of the preceding claims, wherein the first support member and the second support member can be moved between the open position and the closed position by moving the first support member and the second support member along a molding axis, and the second support member can be rotated between the operating orientation and the reloading orientation around an axis parallel to the molding axis.

7. Apparatus according to any preceding claim, wherein the or each second tool half is configured to form an optical surface of the mould half.

8. Apparatus according to any one of the preceding claims, further comprising one or more replacement tool halves configured to be releasably mounted on the second support in place of the second tool half.

9. A portion of an apparatus according to any one of the preceding claims, comprising a first support, a second support and a drive mechanism for moving the first support and the second support between an open position and a closed position and moving the second support between an operating orientation and a reloading orientation.

10. A method of injection molding a mold half for use in manufacturing a contact lens, the method comprising: moving the second support to an operative orientation, and then moving the first support and the second support to a closed position such that one or more first tool halves supported on the first support and one or more second tool halves releasably supported on the second support engage one another to provide corresponding mold cavities therebetween; injecting a molten polymer into the mold cavity and then allowing the molten polymer to solidify in the mold cavity and form a mold half; moving the first support and the second support to an open position so that the one or more first tool halves and the one or more second tool halves are aligned with each other across a partial removal gap; removing the mold half through the partial removal gap; moving the second support member to a reloading orientation in which the one or more second tool halves are located in a tool change region out of alignment with the one or more first tool halves; and The one or more second tool halves are removed from the second support.

11. The method of claim 10, wherein moving the first and second supports to the closed position and moving the first and second supports to the open position each comprises moving the first and second supports along a vertical axis.

12. The method of claim 10 or 11, wherein the step of moving the second support to the reloading orientation also moves one or more third tool halves also releasably supported by the second support into alignment with the one or more first tool halves, and the method further comprises: moving the first support and the second support to another closed position, wherein the second support is in the reloading orientation so that the one or more first tool halves and the one or more third tool halves engage one another to provide corresponding mold cavities therebetween; injecting a molten polymer into the mold cavity and then allowing the molten polymer to solidify in the mold cavity and form an additional mold half; moving the first support and the second support to another open position so that the one or more first tool halves and the one or more third tool halves are aligned with each other across a partial removal gap; and The additional mold half is removed through the partial removal gap.

13. The method of claim 12, wherein moving the second support to the operative orientation also moves the one or more third tool halves to the tool change area.

14. The method of claim 12 or 13, wherein the step of moving the second support to the operative orientation also moves one or more fourth tool halves also releasably supported by the second support into the tool change area.

15. The method according to any one of claims 10 to 14, wherein: Moving the first support and the second support to the closed position and moving the first support and the second support to the open position each include moving the first support and the second support along a molding axis; and Moving the second support to the operating orientation and moving the second support to the reloading orientation each include rotating the second support about an axis parallel to the molding axis.

16. The method of any one of claims 10 to 15, wherein the step of allowing the molten polymer to solidify in the mold cavity and form a mold half comprises allowing some of the molten polymer to solidify against an optical surface provided by the one or more second tool halves so as to form the optical surface of the mold half.

17. The method of any one of claims 10 to 16, further comprising the step of replacing the one or more second tool halves removed from the second support with one or more replacement tool halves.

18. A mould half for manufacturing a contact lens, which is injection moulded using an apparatus according to any one of claims 1 to 9 and / or a method according to any one of claims 10 to 17.

19. A method of manufacturing a contact lens, the method comprising: injection molding a male mold half and injection molding a female mold half, at least one of the mold halves being a mold half according to claim 18; engaging the male mold half and the female mold half with each other, wherein a quantity of contact lens formulation is located in a cavity defined between the male mold half and the female mold half; curing the contact lens formulation to form the contact lens; and The male mold half is separated from the female mold half and the contact lens is removed.

20. A contact lens manufactured using the method of claim 19.

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