Method and apparatus for manufacturing mold halves for forming contact lenses

Abstract

Increased manufacturing costs are reduced or avoided. An apparatus (60) for injection molding mold halves (2, 4) used in the manufacture of 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 and second supports (80, 82) are movable between a closed position in which the first and second tool halves (22, 24) engage with each other to provide a corresponding mold cavity (54) therebetween, and an open position in which the first and second tool halves (22, 24) are aligned with each other across a part removal gap (86). The second support (82) is movable between the operative orientation and a reload orientation in which the second tool half (24) is positioned in a tool change area (64) out of alignment 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 an apparatus and method for quickly inspecting, substituting, or exchanging tooling within an injection molding machine for producing said mold halves. [Background technology]

[0002] Various methods are known for producing contact lenses, including rotational molding, lathing (e.g., diamond turning), and cast molding (e.g., using injection-molded mold halves). Specifically, 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 predetermined amount of contact lens formulation on the optically-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 that encloses the contact lens formulation. The contact lens mold assembly is then subjected to conditions that polymerize or cure the contact lens formulation within the contact lens mold assembly. Contact lenses can be produced in very large quantities, e.g., tens of thousands per day, using high-speed production lines. Increasing the production rate of contact lenses can be expected to reduce the cost of each lens. However, it is important that this increase in production rate does not compromise the quality of the lenses produced.

[0003] When contact lenses are formed using cast molding using injection-molded contact lens mold halves, the process includes many steps. For example, the process of manufacturing mold halves can include closing two injection molding tool halves mounted on the plate of an injection molding machine, forming contact lens mold halves in the closed injection molding mold halves, opening the tool halves containing the injection-molded mold halves, removing the injection-molded mold halves from the open tool halves, and optionally transporting the newly formed mold halves to a transport device for further processing. As will be understood by those skilled in the art, as used herein, injection molding tool halves refer to (usually metallic) inserts used to form the curved surfaces of the contact lens mold halves. The inserts are typically mounted on the plate of the injection molding machine. One or both of the inserts or tool halves will have optical quality surfaces that are used to form the lens-forming surfaces of the contact lens mold halves.

[0004] Mold halves, and particularly their optical surfaces, must be manufactured to high manufacturing tolerances. Therefore, the tooling halves used to mold the mold halves are typically inspected frequently and replaced or repaired upon signs of wear or damage. Furthermore, the same injection molding machine is typically used to manufacture various shapes of mold halves, with each mold half producing a corresponding shape (and therefore optical characteristics) of contact lens. Traditionally, tooling halves are replaced by taking the injection molding machine out of service, replacing the tooling halves (e.g., using a robotic arm), and then restarting the machine. The machine downtime required for tooling changes can significantly increase the overall manufacturing costs of the mold halves and, consequently, the contact lenses produced therefrom. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to mitigate or avoid one of the above mentioned disadvantages and / or to provide an improved or alternative apparatus or part of an apparatus for injection molding of mould halves, a method for injection molding of mould halves, a mould half for producing contact lenses, a method for producing contact lenses or a contact lens. [Means for solving the problem]

[0006] According to a first aspect of the present disclosure, there is provided an apparatus for injection molding mold halves for use in the manufacture of contact lenses, 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 operative orientation, the first and second supports are movable between a closed position in which the first and second tool halves engage with each other to provide corresponding mold cavities therebetween and an open position in which the first and second tool halves are aligned with each other across a part removal gap. The second support is movable between the operative orientation and a reload orientation in which the second tool half is positioned in a tool change area out of alignment with the first tool half.

[0007] According to a second aspect of the present disclosure, there is provided a component of an apparatus according to the first aspect of the present disclosure, said component 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 for moving the second support between said orientations.

[0008] According to a third aspect of the present disclosure, there is provided a method for injection molding mold halves for use in manufacturing contact lenses. The method includes moving a second support to a working orientation and then moving a first support and a second support to a closed position, where 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 corresponding mold cavities therebetween. The method further includes injecting a molten polymer into the mold cavities and then allowing the polymer to solidify within the mold cavities to form the mold halves. The method further includes moving the first and second supports to an open position, where the first and second tool halves are aligned with each other across a part removal gap. The method also includes removing the mold halves through the part removal gap. The method also includes moving the second support to a reload orientation, where the second tool half is positioned in a tool change area 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, there is provided a mould half for producing contact lenses, injection moulded 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, there is provided a method for manufacturing a contact lens. The method includes the steps of 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 the fourth aspect of the present disclosure. The method further includes engaging the male mold half and the female mold half with each other, and disposing a predetermined amount of contact lens formulation into a cavity defined therebetween. The method further includes curing the contact lens formulation to form the contact lens. The method further includes separating the male mold half and the female mold halves to remove 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 explanation of the drawings]

[0012] [Figure 1A] FIG. 1 is a perspective view of two mold halves used in the manufacture of contact lenses. [Figure 1B] 1 is a cross-sectional view of two mold halves used in the manufacture of contact lenses. [Figure 2A] 1B is a perspective view of the two mold halves of FIG. 1A engaging with each other to define a cavity therebetween. FIG. [Figure 2B] 1C is a cross-sectional view of the two mold halves of FIG. 1B engaging with each other to define a cavity therebetween. [Figure 3] 2C is a cross-sectional view of a pair of tool halves used to manufacture the male mold half of FIGS. 1A-2B. FIG. [Figure 4] 2C is a cross-sectional view of a pair of tool halves used to manufacture the female mold half of FIGS. 1A-2B. FIG. [Figure 5] FIG. 5 is a perspective view of an apparatus for injection molding the mold halves of FIGS. 1A to 2B using the pair of tool halves shown in FIGS. 3 and 4. [Figure 6] FIG. 6 is a perspective view of the device of FIG. 5 with the divider removed. [Figure 7] FIG. 7 is a cross-sectional view of the first and second supports of the device of FIGS. 5 and 6. DETAILED DESCRIPTION OF THE INVENTION

[0013] According to a first aspect of the present disclosure, there is provided an apparatus for injection molding of mold halves for use in the manufacture of contact lenses, 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 operative orientation, the first and second supports are 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 the part removal gap; The second support is movable between a working orientation and a reload orientation in which the second tool half is positioned in a tool change area out of alignment with the first tool half.

[0014] The second support is movable between a working orientation and a reload orientation, such that moving the second tool half between alignment with the first tool half and non-alignment with the first tool half at the tool change area can facilitate removal and / or installation of the second tool half from the second support. For example, the tool change area can be 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 installing the second tool half on the second support (e.g., after inspection, repair, or replacement). This ease of access can lead to reduced downtime and, therefore, a lower overall cost for producing a given number of mold halves.

[0015] For the avoidance of doubt, references to first and second supports moving between open and closed positions are intended to mean that the supports move relative to one another. Thus, when moving between positions, the first support can move relative to a stationary second support, the second support can move relative to a stationary first support, or both the first and second supports can move. Embodiments in which the second support remains stationary as the first and second supports move between positions may be advantageous in that the second plate can be moved between both of the orientations, and the required mechanism may be simpler than if the supports were movable between positions.

[0016] The support may be movable along the upright axis between said open and closed positions.

[0017] This may reduce the "footprint" of the apparatus (i.e., the floor space occupied by the apparatus) compared to an arrangement in which the support moves, for example, along a horizontal axis between positions. Alternatively or as well, this may allow gravity to assist in the removal and / or installation of the second tool half from and / or to the second support.

[0018] The apparatus may further include one or more third tool halves releasably mounted on the second support, wherein with the second support in the reload orientation, the first and second supports are movable between a further closed position in which the first and third tool halves engage with each other to provide corresponding mold cavities therebetween, and a further open position in which the first and third tool halves are aligned with each other across the part removal gap.

[0019] This can allow the apparatus to continue injection molding the mold halves using the first tool half and the third tool half while the second tool half is in the mold change area (e.g., removed from or attached to the second support).

[0020] Alternatively, the apparatus may not include any other tool halves apart from the first and second tool halves. In such a configuration, when the second support is in the reloading orientation, an empty region of the second support may be aligned with the first tool half. Such an empty region may also be located in the tool change region when the second support is in the working orientation.

[0021] If the apparatus includes a third tool half, the third tool half can be substantially the same shape as the second tool half (in which case 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 tool halves), or can have a different shape from the second tool half (in which case 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 tool halves).

[0022] With the second support in the working orientation, the third tool half can be positioned in the tool change area.

[0023] This can allow the apparatus to continue injection molding the mold halves using the first and second tool halves while the third tool half is in the mold 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 being removed or attached, and can operate using the first and third tool halves while the second tool half is being removed or attached.

[0024] Alternatively, with the second support in the working orientation, the third tool half can be positioned outside the tool change area, for example, at an intermediate position between the tool change area and a position where the third tool half would be aligned with the first tool half. In such a configuration, the second support can be movable to a further orientation where the third tool half is positioned in the tool change area.

[0025] The apparatus may further comprise one or more fourth tool halves releasably supported on the second support.

[0026] This can improve the versatility of the apparatus: for example, if the second, third, and fourth tool halves are different shapes, the apparatus can produce three different shaped mold halves by simply moving the support between multiple orientations.

[0027] With the second support in the working orientation, the fourth tool half can also be positioned in the tool change area so that it is accessible during the manufacture of mold halves using the first and second tool halves in a manner similar to that described above with respect to the third tool half.

[0028] The support can be movable between an open position and a closed position by moving the support along a molding axis (which can be understood to refer to the axis along which the mold halves are moved into contact with each other to form the mold assembly), and the second support can be movable between an actuation orientation and a reload orientation in a direction perpendicular to the molding axis. For example, the second support can be rotatable between an actuation orientation and a reload orientation about an axis parallel to the molding axis.

[0029] This can allow the mechanism used to move the second support between each orientation to be advantageously simple and / or robust, compared to configurations in which the second support moves in a direction having a component parallel to the forming axis (such as a configuration in which the second support has a shape similar to an escalator, with each ``step'' supporting a different set of tool halves).

[0030] The or each second tool half may be configured to form the optical surfaces of said mold half.

[0031] As noted above, optical surfaces provided on a second tool half that can be conveniently facilitated for removal / attachment can be particularly advantageous because the tool half providing the optical surface is particularly likely to need to be removed for inspection (because the optical surface forms the surface of the mold half that will then form the surface of the finished contact lens) or replaced with a different mold half (because different tool halves will typically require different optical surfaces but can have the same shape on the back side).

[0032] The apparatus may further comprise one or more alternative tool halves configured to be releasably mounted on the second support in place of the second tool half.

[0033] An apparatus that can use an alternate tool half in place of the second tool half can improve the versatility of the apparatus, allowing several mold halves to be produced using the first and second tool halves (and / or the first and third tool halves, and / or the first and fourth tool halves, if present), and different mold halves to be produced using the first tool half and the alternate tool half.

[0034] Alternatively, the apparatus can be configured to function using only the first and second tool halves (and third and fourth tool halves, if present), with individual tool halves being removed and replaced for inspection or repair if necessary.

[0035] According to a second aspect of the present disclosure, there is provided a component of an apparatus according to the first aspect of the present disclosure, said component 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 for moving the second support between said orientations.

[0036] The component may be used to manufacture a device according to the first aspect of the present disclosure, which may result in one or more of the advantages discussed above.

[0037] The drive mechanism can include an electric, hydraulic, or pneumatic motor. Such a motor can be arranged to move the second support between the orientations. When the drive mechanism includes such a motor, the drive mechanism can further include a transmission, such as a chain drive, belt drive, or gearbox, driven by the motor.

[0038] Alternatively or similarly, the drive mechanism can comprise a pneumatic cylinder, a hydraulic cylinder, a solenoid, and / or an electric linear actuator. The drive mechanism can comprise two or more of the above components, e.g., two, three, four, or more. The above component(s) can be configured to move the first and second plates between the open and closed positions.

[0039] According to a third aspect of the present disclosure, there is provided a method of injection molding mold halves for use in the manufacture of contact lenses, the method comprising: moving the second support to an operating orientation, and then moving the first support and the second support to a closed position, wherein 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 one another to provide corresponding mold cavities therebetween; injecting a molten polymer or plastic into a mold cavity and then allowing the polymer or plastic to solidify within the mold cavity to form mold halves; moving the first and second supports to an open position such that the first and second tool halves are aligned with one another across the part removal gap; removing the mold half through a part removal gap; moving the second support to a reload orientation in which the second tool half is positioned in a tool change area out of alignment with the first tool half; removing the second tool half from the second support; Includes.

[0040] Moving the second support between a working orientation and a reload orientation, thereby moving the second tool half between alignment with the first tool half and non-alignment with the first tool half in a tool change area, advantageously facilitates the steps of removing and / or (re)attaching the second tool half. For example, the tool change area can be easily accessible to a worker or 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 inspection, repair, or replacement). This accessibility can lead to reduced downtime and, therefore, reduced overall cost for producing a given number of mold halves.

[0041] The method may use an apparatus according to the first aspect of the present disclosure.

[0042] The steps of moving the support to the closed position and moving the support to the open position may each include moving the support along an upright axis.

[0043] First and second supports that are movable along an upright axis may reduce the "footprint" of the apparatus (i.e., the floor space occupied by the apparatus) compared to, for example, an arrangement in which the supports move along a horizontal axis between positions. Alternatively, or as well, this may allow gravity to assist in the removal and / or installation of the second tool half from and / or to the second support.

[0044] Additionally, the step of moving the second support to the reload orientation may include moving one or more third tool halves, also releasably supported by the second support, into alignment with the first tool halves, the method further comprising: moving the first support and the second support, with the second support in a reload orientation, to a further closed position such that the first tool half and the third tool half engage one another to provide corresponding mold cavities therebetween; injecting molten polymer or plastic into the mold cavity and then allowing the polymer or plastic to solidify within the mold cavity to form a further mold half; moving the first and second supports to a further open position such that the first and third tool halves are aligned with one another across the part removal gap; removing the additional mold half through a part removal gap; may include:

[0045] This can allow the apparatus to continue injection molding the mold halves using the first tool half and the third tool half while the second tool half is in the mold change area (e.g., removed from or attached to the second support).

[0046] Alternatively, the apparatus may not include any other tool halves apart from the first and second tool halves. In such a configuration, by moving the second support to the reload orientation, an empty region of the second support can be moved into alignment with the first tool half. Such empty region can be further moved into the tool change region when the second support is moved to the working orientation.

[0047] The third tool half can also be moved to the tool change area by moving the second support to the working orientation.

[0048] This can allow the apparatus to continue injection molding the mold halves 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 being removed or attached, and can operate using the first and third tool halves while the second tool half is being removed or attached.

[0049] Alternatively, by moving the second support to the working orientation, the third tool half can be moved to a position outside the tool changing area, for example to an intermediate position between the tool changing area and the position where they will be aligned. Such a method can further include moving the second support to a further orientation where the third tool half is located in the tool changing area.

[0050] Moving the second support to the working orientation may also move one or more fourth tool halves, also releasably supported by the second support, to the tool change area.

[0051] This can improve the versatility of the apparatus: for example, if the second, third, and fourth tool halves are different shapes, the apparatus can produce three different shaped mold halves by simply moving the support between multiple orientations.

[0052] Moving the second support to the working orientation can also move the fourth tool half to the tool change area so that the fourth tool half is accessible while the first and second tool halves are being used to manufacture the mold halves in a manner similar to that described above with respect to the third tool half.

[0053] Optionally, each of the steps of moving the first and second supports to the closed position and moving the first and second supports to the open position includes moving the first and second supports along a forming axis, and each of the steps of moving the second support to the working orientation and moving the second support to the reloading orientation includes moving in a direction perpendicular to the forming axis, for example, rotating the second support about an axis parallel to the forming axis (e.g., collinear with the forming axis).

[0054] This can allow the mechanism used to move the second support between each orientation to be advantageously simple and / or robust, compared to configurations in which the second support moves in a direction having a component parallel to the forming axis (such as a configuration in which the second support has a shape similar to an escalator, with each ``step'' supporting a different set of tool halves).

[0055] Optionally, each of the steps of moving the first and second supports to the closed position and moving the first and second supports to the open position comprises moving the first and second supports along a forming axis; The steps of moving the second support to the working orientation and moving the second support to the reloading orientation each include rotating the second support about an axis parallel to the forming axis.

[0056] The step of allowing a polymer or plastic to solidify within the mold cavity to form a mold half may include the step of allowing a portion of the polymer or plastic to solidify in contact with an optical surface provided by the second tool half to form an optical surface of the mold half.

[0057] As noted above, optical surfaces provided on a second tool half that can be conveniently facilitated for removal / attachment can be particularly advantageous because the tool half providing the optical surface is particularly likely to need to be removed for inspection (because the optical surface forms the surface of the mold half that will subsequently form the surface of the finished contact lens) or replaced with a different mold half (because different tool halves will typically require different optical surfaces but can have the same shape on the back side).

[0058] The method may further include attaching the second tool half to the second support, e.g., reinstalling a second tool half previously removed from the second support, or installing one or more replacement second tool halves (e.g., if the second tool half is worn or damaged). Alternatively, the method may further include replacing the second tool half removed from the second support with one or more replacement tool halves.

[0059] An apparatus that can use an alternate tool half in place of the second tool half can improve the versatility of the apparatus, allowing several mold halves to be produced using the first and second tool halves (and / or the first and third tool halves, and / or the first and fourth tool halves, if present), and different mold halves to be produced using the first tool half and the alternate tool half.

[0060] Alternatively, the apparatus can be configured to function using only the first and second tool halves (and third and fourth tool halves, if present), with individual tool halves being removed and replaced for inspection or repair if necessary.

[0061] According to a fourth aspect of the present disclosure, there is provided a mould half for producing contact lenses, injection moulded using the apparatus of the first aspect of the present disclosure and / or the method of the second aspect of the present disclosure.

[0062] Mold halves produced in this manner may be cheaper to produce, for example, due to the reduced downtime discussed above.

[0063] According to a fifth aspect of the present disclosure, there is provided a method of manufacturing a contact lens, the method comprising: injection molding a male mold half and a female mold half, at least one of the mold halves being a mold half according to the fourth aspect of the present disclosure; engaging a male mold half and a female mold half with one another, wherein a predetermined amount of contact lens formulation is disposed within a cavity defined therebetween; curing the contact lens formulation to form the contact lens; separating the male and female mold halves to remove the contact lens; Includes.

[0064] It can be understood that curing of the contact lens formulation occurs by polymerization.

[0065] A method using a mold half according to the fourth aspect of the present disclosure can reduce the costs associated with the mold half for the reasons described above, thereby reducing the manufacturing costs of the contact lenses.

[0066] The method may include further steps, such as cleaning or rinsing the contact lens and / or hydrating the contact lens.

[0067] 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.

[0068] For the reasons stated above, such contact lenses can be manufactured inexpensively.

[0069] Those skilled in the art will understand that certain features of the embodiments of the present disclosure described herein that are incompatible with each other may be present in any combination in exemplary embodiments of the present disclosure. Optional or preferred features described in connection with one aspect of the present disclosure may be applicable to other aspects of the present disclosure, where appropriate.

[0070] While reference is made herein to mold halves, it should be understood that two mold halves can complement each other and together form a mold assembly, and that each mold half is not necessarily half or 50% of the mold assembly. One mold half can include 20%, 30%, 40%, 45%, etc. of the mold assembly, and the other mold half can include 80%, 70%, 60%, 55%, etc. of the mold assembly. Thus, while two mold halves can make an entire mold assembly, it should be understood that the two mold halves need not be the same size or mirror images of each other. Similarly, while reference is made herein to tool halves, it should be understood that the two mold halves that complement each other and together define a mold cavity need not be the same size or mirror images of each other.

[0071] Referring to the drawings, Figures 1A and 1B (and Figures 2A and 2B) show mold halves used in the manufacture of contact lenses: a male mold half 2 and a female mold half 4. Each mold half 2, 4 has alignment tabs 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.

[0072] The male and female mold halves 2, 4 can be engaged with one another as shown in Figures 2A and 2B. With the mold halves 2, 4 so engaged, they are sealed together and the convex optical surface 10 of the male mold half 2 projects into the concave optical surface 10 of the female mold half 4. The two optical surfaces 10 thereby form a cavity 16 within which a contact lens can be molded.

[0073] To manufacture a contact lens using the mold halves 2, 4, a predetermined amount of contact lens formulation is placed in or on the concave optical surface 10 of the female mold half 4, and the male and female mold halves 2, 4 are then mated together. Once the mold halves 2, 4 are mated, the contact lens formulation is spread to substantially fill the cavity 16. The mold halves 2, 4, enclosing the contact lens formulation, are then treated, for example, with heat or ultraviolet light, to harden the formulation into a polymeric contact lens. The mold halves 2, 4 can then be separated to release the contact lens, which is then washed to remove residual chemicals, such as unreacted monomers, that do not form part of the polymerized contact lens. The lens is then hydrated and packaged for use.

[0074] Each of the mold halves 2, 4 is manufactured by injection molding into a cavity formed between a pair of tool halves. Figure 3 shows a pair of 20 tool halves used to manufacture the male mold half 2, and Figure 4 shows a pair of 20 tool halves used to manufacture the female mold half 4. Each pair includes a first tool half 22 and a second tool half 24.

[0075] Each first tool half 22 includes an injection nozzle 26, a thermocouple 28, a tool portion 30, and an ejection mechanism (not visible) positioned to eject the formed mold half. A coolant passage (not visible) is provided behind the tool portion 30, passing at its closest point approximately 4 mm from its outermost surface 32. The injection nozzle 26 and thermocouple 28 of the first tool half 22 are positioned away from the center of the tool portion 30. This allows space for the coolant passage to pass near the outer surface 32 of the tool portion 30, which forms the surface of the contact lens mold half used to cast mold the optic zone of a contact lens.

[0076] Each second tool half 24 in this embodiment takes the form of a collet 40 that supports a tool insert 42. Each collet 40 has a front disk portion 43 and a frusto-conical portion 44. The frusto-conical portion 44 has a coolant passage 45 that runs from below its center to the rear of the tool insert 42 and back, and includes an annular groove 46 toward its rear. As will be described below, each second tool half 24 is supportable on a second support. More specifically, in this embodiment, each second tool half 24 is supportable within a respective bushing 48 of the second support. The bushings 48 in this embodiment also have a coolant passage 50 extending around their periphery.

[0077] The first tool half 22 can be clamped in place to the bushing 48 by respective clamps (not shown) that engage grooves 46 in the collet 40 to prevent withdrawal of the frusto-conical portion 44 from the bushing 48, and can therefore be attached to a second support. Each second tool half 24 can be unclamped, removed, and replaced independently of the other second tool halves, allowing for flexible replacement of the second tool halves 24. Furthermore, each collet 40 can support a different tool insert 42.

[0078] The second tool half 24 of each pair 20 provides an optical surface 52. In the case of the second mold half 24 of FIG. 3, the optical surface 52 of the second tool half is concave and defines the convex optical surface 10 of the male mold half 2. In the case of the second mold half 24 of FIG. 4, the optical surface 52 of the second mold half is convex and defines the concave optical surface 10 of the female mold half 4. In either case, in this example, the optical surface 52 of the second tool half 24 is provided on a tool insert 42. Thus, the shape of the optical surface 52 of the second tool half 24, and therefore the shape of the optical surface 10 of the mold halves 2, 4 (and therefore the shape and optical properties of the contact lens produced thereby) can be changed by changing the tool insert 42 of the second tool half 24.

[0079] 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. Thus, the outermost surface 32 of the tool portion 30 of the first tool half 22 in FIG. 3 is convex, and the outermost surface 32 of the tool portion 30 of the first tool half 22 in FIG. 4 is concave. The exact shape of these surfaces is not critical, as they do not form the surfaces of the mold halves 2, 4 that form the surfaces of the contact lens. Thus, the same first tool half 22 can be used with multiple different second tool halves (e.g., with multiple different tool inserts 42 mounted in the same collet 40 and / or with multiple different sets of collets 40, each having a different tool insert 42).

[0080] 3 and 4 show the pair 20 of tool halves 22, 24 engaged with one another. When so engaged, the first and second tool halves 22, 24 form a mold cavity 54 into which molten polymer or plastic can be injected (through injection nozzle 26) and cooled to form the respective mold halves 2, 4.

[0081] 5 illustrates an embodiment of an apparatus 60 for injection molding mold halves utilizing first and second tool halves 22, 24 as described above. The apparatus includes an injection molding area 62 and a tool change area 64 separated from one another by a partition 66 including a sliding door 68. The apparatus 60 also includes a tool change robot 70, a tool storage section 72, and an retrieval robot 74 having a plate 76. Additionally, as shown in FIG. 6, the apparatus includes a first support 80 and a second support 82.

[0082] FIG. 6 shows the apparatus 60 with the divider 66 removed, more clearly showing the first and second supports 80, 82, and FIG. 7 shows a cross-section of this area. Mounted on the first support 80 are a set of first tool halves 22 of the type shown in FIGS. 3 and 4. Removably mounted on the second support 82 are a set of second tool halves 24 of the type shown in FIGS. 3 and 4, as will be described in more detail below. In this particular embodiment, the first support 80 has four first tool halves 22 of the type shown in FIG. 3 and four first tool halves 22 of the type shown in FIG. 4. Similarly, the second support 82 has four second tool halves 24 of the type shown in FIG. 3 and four second tool halves 24 of the type shown in FIG. 4. The first and second supports 80, 82 hold the first and second tool halves 22, 24 within their respective mounting plate assemblies 84. Like component numbers in Figures 5-7 refer to the same components as described herein.

[0083] Figures 5-7 show the second support 82 in a predetermined operating orientation. With the second support 82 in this orientation, the first and second supports 80, 82 are movable relative to one another between an open position and a closed position (as shown in Figures 5-7). With the supports 80, 82 in the open position, the first and second tool halves 22, 24 are aligned with one another across the part removal gap 86. With the supports 80, 82 in the closed position, the aligned first and second tool halves 22, 24 are engaged with one another in the manner shown in Figures 3 and 4.

[0084] In this embodiment, the supports 80, 82 are movable between open and closed positions by moving the first support 80 along a vertically oriented molding axis 88, guided by a set of guide rods 89 extending parallel to the molding axis 88. The first support is attached by a pair of hydraulic cylinders 94 of the apparatus's drive mechanism to a stationary feed unit 90 that also supports a hopper 92 holding the polymer or plastic granules to be injection molded. To move the first support 80 to the closed position, the cylinders 94 extend to lower the first support 80 along the molding axis 88 toward the second support 82, and to move the first support 80 to the open position, the cylinders 94 retract to raise the first support 80 along the molding axis 88 away from the second support 82.

[0085] In this embodiment, the second support 82 also has a set of third tool halves 96 removably mounted on another mounting plate assembly 84a. The third tool halves 96 are generally similar to the first tool halves 22, except that the tool inserts 42 have a slightly different shape, causing the mold halves 2, 4 produced thereby to also have slightly different shapes. Accordingly, the contact lenses produced using those mold halves 2, 4 will also have slightly different shapes and, therefore, slightly different optical properties. As shown, with the second support 82 in the working orientation, the third tool halves are positioned in the tool change area.

[0086] The second support 82 is movable between a working orientation and a reloading orientation. More particularly, in this embodiment, the second support forms a turntable that can rotate under the action of an electric motor (not visible) of a drive mechanism of the apparatus 60. The second support 82 is rotatable about an axis 98 that is parallel to the forming axis 88 in this embodiment. The sliding door 68 of the divider plate 66 can be lifted when the second support 82 is rotated, providing sufficient clearance for the plate assembly 84 to pass under the divider plate 66.

[0087] With the second support 82 in the reloading orientation, the second tool half 24 is positioned in the tool change area, i.e., not aligned with the first tool half 22, and the third tool half 96 is positioned in the injection molding area 62 aligned with the first tool half 22. The second tool half 24 is easily accessible because it is in the tool change area 64. In this embodiment, the tool change robot 70 is configured to remove the second tool halves 24 from the second support 82, install them in the tool storage 72, and then replace the second tool halves 24 with a set of replacement tool halves 99 previously stored in the tool storage 72. However, in other embodiments, replacement tool halves 99 may not be provided, and the tool change robot may remove one second tool half 24 at a time before reinstalling them in the second support 82, for example, for inspection or replacement of a tool insert.

[0088] Just moving the second support 82 from the working orientation to the reload orientation moves the second tool half 24 from alignment with the first tool half 22 to out of alignment with the first tool half 22 at the tool change area 64, which also moves the third tool half 96 from the tool change area to alignment with the first tool half 22 at the injection molding area 62. With the second support 82 in this position, the first and second supports 80, 82 are movable between a further open position in which the first and third tool halves 22, 96 are aligned with one another across the part removal gap, and a closed position in which the first and third tool halves 22, 96 engage one another in the same manner as described above with respect to the first and second tool halves 22, 24.

[0089] Thus, with the second support 82 in the reload 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 required for the drive mechanism of the apparatus 60 to rotate the second support 82 from the working orientation to the reload orientation (approximately 4 seconds in this example).

[0090] In a corresponding manner, with the second support 82 in the working orientation, i.e., with the second tool half 24 aligned with the first tool half 22 in the injection molding area and the third tool half 96 in the tool change area 64, the tool change robot 70 can remove the third tool half 96 for inspection or replacement.

[0091] To injection mold the mold halves 2, 4, the second support 82 is moved to the working orientation and the first and second supports 80, 82 are moved to the closed position so that the first and second tool halves 22, 24 define the mold cavities 54 as described above. Polymer or plastic pellets from a hopper 92 are heated above their melting point, and the resulting liquid polymer / plastic flows into a manifold (not visible) and then through the injection nozzles 26 of the first tool half 22 (see Figures 3 and 4) into the cavities 54. Further heating is provided by coils (not visible) around each injection nozzle 26. Thermocouples 28, located on the opposite side of the first tool half 22 from the injection nozzles 26, are used to monitor the temperature of the injected polymer / plastic. Heating of the nozzles 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. Inconsistent flow rates create stresses in the molding mold, resulting in distortions and inconsistencies in the contact lenses molded from the mold, such as different fits, different radii, and therefore different powers. Careful control of pressure and cooling results in consistency and uniformity; in contrast, insufficient control can lead to the need to selectively stop injection into cavities where the flow rate deviates significantly from the target value.

[0092] Once the cavity 54 is filled with the polymer or plastic and the desired hold pressure profile is applied, a stop pin (not shown) in the injection nozzle 26 advances to block the injection nozzle 26 from the cavity 54, thereby stopping the flow of polymer / plastic. A coolant, such as water, circulates through the coolant passages 45, 50 to cool the polymer / plastic, thereby forming the mold halves, and the polymer / plastic solidifies against the optical surface 52 of the tool insert 42, forming the optical surface 10 of the mold halves 2, 4. The coolant passages 45, 50 in the tool halves 22, 24 pass near the outermost surface 32 of the tool portion and the optical surface 52 of the tool insert 42. This arrangement provides direct cooling of the portions of the mold halves 2, 4 that form the optical zone of the lens as they are formed within the cavity (rapid cooling of the nucleated material results in a good quality, uniform mold; without nucleation, slower cooling in the center of the material can occur, resulting in the formation of larger crystals in the center of the material).

[0093] Once the polymer / plastic solidifies, resulting in the formation of the mold halves 2, 4, the hydraulic cylinder 94 lifts the first support 80 to move the supports 80, 82 to an open position, separating the mold halves 22, 24 and opening the cavity 54. The newly formed mold halves 2, 4 remain on the first tool half 22 as the first support 80 is lifted. The removal robot 74 then inserts the plate 76 into the part removal gap 86. An ejection mechanism (not visible) then pushes the mold halves 2, 4 off the first tool half 22 so that they can be collected onto the plate 76 using a high airflow vacuum. The removal robot 74 then transports the mold halves 2, 4 on the plate through the part removal gap 86 and away from the injection molding area 62 for further processing (further cooling, quality inspection, or immediate use in the production of contact lenses as described above).

[0094] Further mold halves 2, 4 can be fabricated following these steps. Whenever inspection or replacement of the second tool half 24 is necessary, or when it is desired to fabricate a mold half 2, 4 in the shape produced by the third tool half 96, the second support 82 places the second tool half 24 in the tool change area 64 and moves the third tool half 96 to a reload orientation to position it in alignment with the first tool half 22. The tool change robot 70 can then remove the second tool half 24 or replace it with a replacement tool half 99, as described above. While this is happening, the apparatus can continue to injection mold further mold halves 2, 4 using the same steps as above with the first and third tool halves 22, 96, but with the supports 80, 82 moving between the further open and further closed positions.

[0095] Similarly, whenever the third tool half 96 needs to be inspected or replaced, or when it is desired to produce a mold half 2, 4 in the shape produced by the first tool half 24 (or an alternative tool half 99, if installed on the second support 82), the second support 82 is moved to the operating orientation to install the third tool half 96 in the tool change area 64 and to install the second tool half 24 (or an alternative tool half 99) in alignment with the first tool half 22.

[0096] In this example, the production monitoring software logs whenever the set of tool halves 24, 96 used with the first tool half 22 to manufacture the mold halves 2, 4 is changed 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 autonomously managed. This can avoid the need to physically separate different batches of mold halves 2, 4 manufactured using different sets of mold halves 24, 96 (e.g., package them in different containers for future processing).

[0097] While the present disclosure has been described and illustrated with reference to specific embodiments, those skilled in the art will recognize that the present disclosure is amenable to many different variations not specifically illustrated herein. By way of example only, in a variation of the above apparatus, the second support can include a fourth set of tool halves as well as the second and third tool halves. In this example, the divider plate can be shaped so that the second support can align any one of the tool half sets with the first tool half, while one or both of the other tool half sets on the second support can be positioned in the tool change area. As another example, while the above example has two different types of first tool halves, two different types of second tool halves, etc., other arrangements can have first tool halves that are all identical to each other and second tool halves that are all identical to each other (in which case a tool change must occur before both the male and female mold halves are manufactured). Alternatively, other embodiments may have four different types of first tool halves, four different types of second tool halves, etc., allowing complete sets of mold halves for two different types of contact lenses to be produced at once.

[0098] For the avoidance of doubt, the use of terms such as "first tool half," "second tool half," and the like should not be construed as implying any limitations beyond those set forth in the claims. No implication is intended regarding the structure or order of use of the tool halves. For example, the second and third tool halves may be identical to one another in some embodiments, and / or a first use of the apparatus may utilize the third tool half before the second tool half. Furthermore, while the apparatus described above has eight first tool halves mounted on the first support (and eight second tool halves and eight third tool halves mounted on the second support), it should be understood that this should not be construed as limiting. In variations of the apparatus, there may be fewer than eight (e.g., 1, 2, or 4) first tool halves mounted on the first support, or there may be more than eight first tool halves mounted on the first support, with a corresponding number of second tool halves (and, if applicable, a corresponding number of third tool halves) mounted on the second support.

[0099] Where the foregoing description refers to an element or element having known, obvious, or foreseeable equivalents, such equivalents are incorporated herein as if individually set forth. Reference should be made to the claims to determine the true scope of the present disclosure, which should be construed to encompass any such equivalents. The reader should also understand that any element or feature of the present disclosure described as preferred, advantageous, convenient, or the like is optional and does not limit the scope of the independent claims. Furthermore, it should be understood that while such optional element or feature may be advantageous in some embodiments of the present disclosure, it may be undesirable in other embodiments and, therefore, may not be present. [Explanation of symbols]

[0100] 2 Mold halves 4 Mold halves 22 First Tool Half 24 Second Tool Half 54 Mold cavity 60 equipment 64 Tool change area 80 First Support 82 Second Support 86 Parts removal gap

Claims

1. 1. Apparatus for injection molding contact lens mold halves for use in the manufacture of contact lenses, said 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 operative orientation, the first and second supports are 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 part removal gap; The apparatus, wherein the second support is movable between the working orientation and a reload orientation in which the second tool half is positioned 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 an upright axis between the open position and the closed position.

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

4. The apparatus of claim 3 , wherein the third tool half is positioned in the tool changing area with the second support in the working orientation.

5. 5. The apparatus of claim 3 or 4, further comprising one or more fourth tool halves releasably supported on the second support.

6. 6. The apparatus of claim 1, wherein the first support and the second support are movable between the open position and the closed position by moving the first support and the second support along a forming axis, and the second support is rotatable between the working orientation and the reloading orientation about an axis parallel to the forming axis.

7. 7. The apparatus of claim 1, wherein the or each second tool half is configured to form an optical surface of the mold half.

8. 8. The apparatus of claim 1, further comprising one or more alternative tool halves configured to be releasably mounted on the second support in place of the second tool half.

9. 9. A component of an apparatus according to claim 1, comprising the first support, the second support, and a drive mechanism for moving the first support and the second support between the open position and the closed position and for moving the second support between the working orientation and the reload orientation.

10. 1. A method of injection molding mold halves for use in the manufacture of contact lenses, comprising: moving a second support to an operating orientation, and thereafter moving the first support and the second support to a closed position, wherein 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 a mold cavity therebetween; injecting molten polymer into the mold cavity and then allowing the molten polymer to solidify within the mold cavity to form mold halves; moving the first support and the second support to an open position such that the one or more first tool halves and one or more second tool halves are aligned with one another across a part removal gap; removing the mold half through the part removal gap; moving the second support to a reload orientation in which the one or more second tool halves are positioned in a tool change area out of alignment with the one or more first tool halves; removing the one or more second tool halves from the second support; A method comprising:

11. 11. The method of claim 10, wherein each of the steps of moving the first support and the second support to a closed position and moving the first support and the second support to an open position comprises moving the first support and the second support along an upright axis.

12. The step of moving the second support to the reload 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, the method further comprising: moving the first support and the second support, with the second support in the reload orientation, to a further closed position such 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 molten polymer into the mold cavity and then allowing the molten polymer to solidify within the mold cavity to form a further mold half; moving the first support and the second support to a further open position such that the one or more first tool halves and the one or more third tool halves are aligned with one another across a part removal gap; removing the additional mold half through the part removal gap; 12. The method of claim 10 or 11, comprising:

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

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

15. each of the steps of 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 includes moving the first support and the second support along a forming axis; each of the steps of moving the second support to the working orientation and moving the second support to the reload orientation includes rotating the second support about an axis parallel to the forming axis; 15. The method according to any one of claims 10 to 14.

16. 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 to form a mold half includes the step of allowing a portion of the molten polymer to solidify in contact with optical surfaces provided by the one or more second tool halves to form optical surfaces of the mold half.

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

18. 18. A mould half for producing contact lenses, 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. 1. A method of manufacturing a contact lens, comprising: injection molding a male mold half and 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 one another, wherein a predetermined amount of contact lens formulation is disposed within a cavity defined therebetween; curing the contact lens formulation to form the contact lens; separating the male and female mold halves to remove the contact lens; A method comprising:

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

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