GB2559167B - End effector for a robot in a contact lens manufacturing process - Google Patents

Description

End Effector For A Robot In A Contact Lens Manufacturing Process

The present invention relates to an end effector for a robot used in a contact lens manufacturing process; a robot; a contact lens manufacturing system; and a process for manufacturing contact lenses.

It is known to use robots having end effectors in contact lens manufacturing processes to move contact lens moulds within a manufacturing cell. Typically, existing manufacturing systems involve the contact lens moulds being de-moulded by the robot and released from the end effector at an early stage. The moulds are either placed in storage trays or handed over to tooling located on separate machinery prior to secondary operations taking place. This increases the likelihood of contact lens mould damage, can increase cycle time and can significantly increase the foot print (floor area) of the machinery, which is undesirable since space inside a clean room environment is an expensive commodity. The inventors have determined that some of these problems can be addressed by maintaining the contact lens moulds in the end effector for at least some of the secondary manufacturing operations. However this alone does not provide a fully optimised solution.

Accordingly the present invention seeks to mitigate at least one of the aforementioned problems, or at least provide an alternative to existing apparatus and processes. In particular, the invention seeks to provide an end effector for a robot, a robot, a contact lens manufacturing system, and a contact lens manufacturing process that mitigates at least one of the above-mentioned problems.

According to one aspect of the invention there is provided an end effector for a robot in a contact lens manufacturing process according to claim 1. The invention enables the first mould support to be separated from the robot during a contact lens manufacturing process, so that the contact lens moulds, or parts thereof, carried by the first mould support can be left at a processing satiation, while the robot attends to another task. For example, the robot can select a new first support mould and move it to an Injection Moulding Machine to collect a new batch of contact lens mould parts, while the processing station is operating on an earlier batch. The original first support mould can be reattached to the robot at a later time, or can be attached to another robot in the manufacturing cell.

Releasing all or part of the end effector during a contact lens manufacturing process reduces the likelihood of contact lens mould damage since the moulds remain in the end effector, can reduce cycle times and can decrease the foot print of the manufacturing cell. The invention can also increase cycle throughput as many of the secondary operations, such as dispensing monomer, inserting the male mould into the female mould, and closing and retaining the moulds, can take significantly longer than the time taken for moulding or producing new moulds. Advantageously the end effector can include a body for connecting the first support mould to the robot.

In preferred embodiments the attachment means is arranged to releasably attach the first mould support to the end effector body. In this arrangement the end effector body is typically fixed to the robot during a contact lens manufacturing process.

In some embodiments the attachment means is arranged to releasably attach the end effector body to the robot. In this arrangement, at least a part of the end effector body is detachable from the robotic arm during a contact lens manufacturing process.

The attachment means includes an actuator arranged to receive control signals from the control system, and in response to said control signals, is arranged to selectively attach the first mould support to the robot, and/or detach the first mould support from the robot.

The first mould support includes ferromagnetic material and the attachment means includes at least one controllable magnetic device for selectively attracting the first mould support to the magnetic device. For example, the controllable magnetic device can include an electromagnet that has a non-energized (or low energy) state, wherein the first mould support is not (or is weakly) attracted to the magnetic device. The electromagnet can be actuated to an energised state wherein the first support mould is strongly attracted to the magnetic device. In preferred embodiments the end effector includes a plurality of controllable magnetic devices. When energised, the or each magnetic device strongly holds the first support mould in place. The or each magnetic device is mounted on the end effector body, preferably towards a leading end thereof. When the or each controllable magnetic device is in the non-energised state, the first mould support is detachable from the magnetic devices, and hence the end effector body.

The first mould support includes a plurality of mould receiving formations wherein each mould receiving formation is arranged to receive a contact lens mould, or at least a part thereof. For example, each mould receiving formation can be arranged to receive a female part of a contact lens mould. Preferably each mould receiving formation comprises a recess formed in a first mould support body. Preferably each recess is substantially cylindrical in shape. Preferably each recess is arranged substantially parallel to one another. Each recess has an opening facing in an outwardly direction for receiving the contact lens mould, or at least a part thereof.

Advantageously the mould receiving formations can be arranged around a pitch circle. The mould receiving formations are substantially evenly spaced around the pitch circle.

Advantageously at least some of the mould receiving formations can include a liner. The liners are preferably made from steel. However other materials can be used, for example the liners can be made from rubber, for example can be in the form of rubber vacuum cups. Preferably each liner protrudes outwardly from the recess. Advantageously each liner has an open base. Advantageously each liner is open at its outer end.

Advantageously at least one of the mould receiving formations can be connected to a first air pathway. The first air pathway is part of a pneumatic system. The pneumatic system is arranged to selectively apply a negative pressure to the at least one mould receiving formation via the first air pathway. For example, the pneumatic system can be arranged to provide a negative pressure to the interior of each recess. The first mould support can include a manifold having a least the first pathway formed therein. A hole can be formed in the base of at least one of recesses which connects the interior of the recess to the first air pathway formed in the manifold.

Advantageously the pneumatic system can include a negative pressure source, such as a vacuum pump. The pneumatic system can include at least one vacuum switch. When activated, the negative pressure source generates a negative pressure in at least one of the mould receiving formations, and preferably each of the mould receiving formations. The effect of the negative pressure is to hold the contact lens moulds, or parts thereof, in contact with the mould receiving formations by means of a suction force. When the negative pressure is removed, for example by deactivating the negative pressure source, the pressure within the mould receiving formations normalises, and the contact lens moulds, or parts thereof, can be removed from their respective formations. In some embodiments positive pressure can be applied to remove the vacuum quickly to assist with removal of the moulds from the liners. The suction force can be applied to the contact lens moulds, or parts thereof, for example when the robot is moving the first mould support. The pneumatic system can include a controller for controlling operation of the negative pressure source and/or the vacuum switches. Preferably the controller operates in accordance with signals received from the control system.

Advantageously the first air pathway can include a first port. The end effector can include a first pneumatic connector arranged to releasably connect with the first port. The first port can comprise, for example an externally facing hole formed in the manifold.

Advantageously at least one of the mould receiving formations can be connected to a second air pathway. The second air pathway is part of the pneumatic system. The second air pathway can include a second port. The end effector can include a second pneumatic connector for releasably connecting with the second port. The pneumatic system can be arranged to selectively apply a negative pressure to at least one of the mould receiving formations via the second air pathway.

In preferred embodiments at least one, and preferably each, of the first and second pneumatic connectors comprises a suction cup. Each pneumatic connector is connected to at least one pneumatic line. Preferably each pneumatic line connects its respective pneumatic connector to the negative pressure source.

Advantageously the first mould support can include a spring loaded vacuum cup for applying a suction force to sprue attached to the contact lens moulds.

Advantageously the first mould support can include a third air pathway. The third air pathway can include a third port. The end effector can include a third pneumatic connector for releasably connecting with the third port, thereby connecting the spring loaded vacuum cup to the pneumatic circuit. Preferably the third pneumatic connector is in the form of a suction cup. The third pneumatic connector can be connected to the negative pressure source via a pneumatic line.

Advantageously one of the first mould support and the end effector body can include a first male locating formation and the other of the first support mould and the end effector body includes a first female locating formation. For example, the first male locating formation can comprise a locating pin. The first female locating formation can comprise a bush or bearing.

Advantageously one of the first mould support and the end effector body can include a second male locating formation and the other of the first support mould and the end effector body includes a second female locating formation. For example, the second male locating formation can comprise a locating pin. The second female locating formation can comprise a bush or bearing. Using locating pins and bushes or bearings ensures that the first mould support is very accurately located respect to the end effector body every time it is attached to the robot. This is important to ensure that during operation of the robot the contact lens moulds, or parts thereof, are properly aligned with the recesses and tools in the process stations. In some arrangements, positional tolerances need to accumulate to no more than 0.1mm, therefore it is critical that the first support mould is correctly and accurately mounted with respect to the end effector body every time. In preferred embodiments, the male locating formations are mounted to the end effector body and the female locating formations are formed in the first support member.

Advantageously the first mould support can include at least one additional locating formation for accurately locating the first mould support onto an end effector body. In preferred embodiments the first mould support includes a first pair of female locating formations arranged to receive male locating formations located on the end effector body. In preferred embodiments the first mould support includes a second pair of female locating formations arranged to receive male locating formations located on the end effector body.

Advantageously the end effector can include at least one locating formation for accurately locating the position of the first mould support with respect to a manufacturing station. In preferred embodiments, the first mould support includes at least one locating formation for locating the position of the first mould support with respect to a manufacturing station. In particularly preferred embodiments the first mould support includes first and second locating formations for locating the position of the first mould support with respect to a manufacturing station.

Advantageously the end effector can include a second mould support arranged to support a plurality of contact lens moulds, or parts thereof.

Advantageously the second mould support can be attached to the end effector body. When the first mould support is attached to the robot, the first and second mould supports are typically oriented to face in the same general direction.

Advantageously the second mould support can include a plurality of mould receiving formations, wherein each mould receiving formation is arranged to receive a contact lens mould, or part thereof. Preferably each mould receiving formation is arranged to receive male mould parts. Preferably each mould receiving formation comprises a recess formed in a second mould support body. Preferably each recess is substantially cylindrical in shape. Preferably each recess is arranged substantially parallel to one another. Each recess has an opening facing in an outwardly direction for receiving the contact lens mould, or a part thereof. The mould receiving formations are preferably arranged substantially evenly around a pitch circle. At least some of the mould receiving formations include liners. Preferably each liner is made from a plastics material. Preferably each liner protrudes outwardly from the recess. Preferably each liner has an open base.

Advantageously each mould receiving formation can be connected to at least one air pathway. The or each pathway is part of a pneumatic system. The pneumatic system is arranged to selectively apply a negative pressure to at least one of the mould receiving formations, and preferably each of the mould receiving formations. For example, the interior of each recess is connected to at least one air pathway formed in the second mould support, and the pneumatic system is arranged to selectively apply a negative pressure to the interior of the recesses via the at least one air pathway. The second mould support can include a manifold having the at least one air pathway formed therein. A hole can be formed in the base of each recess which connects the interior of each recess to one of the air pathways. The effect of the negative pressure is to hold the contact lens moulds, or parts thereof, in contact with the mould receiving formations by way of a suction force. When the negative pressure is removed, the pressure within the recesses normalises, and the contact lens moulds, or parts thereof, can be removed from respective formations. The suction force can be applied to the contact lens moulds, or parts thereof, for example when the robot is moving the second mould support.

Advantageously the second mould support can include at least one air pathway port. The air pathway port can comprise, for example an externally facing hole formed in the manifold. Preferably the second mould support includes at least first and second air pathways. Preferably the first air pathway includes a first port. Preferably second air pathway includes a second port. Preferably at least one mould receiving formation is connected to the first air pathway. Preferably at least one other recess is connected to the second air pathway.

According to another aspect of the invention there is provided a robot including an end effector according to any configuration described herein.

Advantageously the arm can comprise an articulated arm. Preferably the robot comprises a multi-axis robotic arm, typically having three or more axes. For example, four, five, or six axes.

According to another aspect of the invention there is provided a manufacturing system for manufacturing contact lenses including a first robot according to any configuration described herein.

Advantageously the manufacturing system can include a second robot according to any configuration described herein. The manufacturing system can include at least one additional robot according to any configuration described herein. Some manufacturing systems include multiple robots according to any configuration described herein.

Advantageously the manufacturing system can include at least one of the following: an injection moulding machine for producing contact lens male and female mould parts; a sprue waste chute; a dispensing unit for dispensing liquid plastic into the contact lens moulds; at least one close and weld unit; a printing unit; intermediate storage locations for receiving at least one first mould support; a contact lens curing unit; or any combination thereof; and a control system for controlling operation of the manufacturing system.

According to another aspect of the invention there is provided a process for manufacturing contact lenses, including: providing a robot according to any configuration described herein; releasably attaching a first mould support to the robot; the first mould support receiving a batch of contact lens moulds, or parts thereof; transporting the first mould support to a first processing station; and detaching the first mould support from the robot.

Advantageously the process can include providing a second robot according to any configuration described herein.

Advantageously the process can include releasably attaching the first mould support to the second robot.

Advantageously the process can include releasably attaching a new first support mould to the first robot. The process can include the new first mould support receiving a batch of contact lens moulds, or parts thereof. The process can include transporting the new first mould support to the first processing station, or a different processing station. The process can include detaching the new first mould support from the first robot.

Advantageously the process can include the second robot moving the first mould support to a second processing station.

Advantageously the process can include detaching the first mould support from the second robot.

Advantageously the process can include the second robot moving the first mould support to a storage location. The process can include reattaching the first mould support to the first robot.

Advantageously the process can include releasably attaching the new first support mould to the second robot. The process can include detaching the new first support mould from the second robot.

Advantageously the process can include, each processing station comprising one of the following: an injection moulding machine for producing contact lens male and female mould parts; a sprue waste chute; a dispensing unit for dispensing liquid plastic into the contact lens moulds; at least one close and weld unit; a printing unit; intermediate storage locations for receiving at least one first mould support; a contact lens curing unit.

According to another aspect of the invention there is provided a robot, including: an arm; a first mould support arranged to support a plurality of contact lens moulds, or at least parts thereof; and attachment means for releasably attaching the first mould support to the arm, said attachment means being arranged to attach the first mould support to the arm and/or detach the first mould support from the arm during a contact lens manufacturing process according to signals received from a control system.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic view of a contact lens manufacturing cell in accordance with the invention;

Figure 2 is a plan view of the manufacturing cell of Figure 1;

Figure 3 is a high level diagrammatic view of a control arrangement of the manufacturing cell of Figure 1;

Figure 4 is a plan view of part of the manufacturing cell of Figure 1;

Figure 5 is an isometric view of a first robot used in the manufacturing cell of Figure 1;

Figure 6 is an isometric view of a first end effector from the first robot, in a first configuration having first and second mould supports;

Figure 7 is a plan view of the first end effector in the first configuration;

Figure 8 is an isometric view of the first end effector in a second configuration having only the second mould support, the first mould support is detached;

Figure 9 is a plan view of the first end effector in the second configuration;

Figure 10 is a diagrammatic view of a vacuum system, which provides a negative pressure (suction) to suction cups included in the first end effector;

Figure 11 is a diagrammatic view of a system for releasably attaching the first mould support to a fixed part of the first end effector;

Figure 12 is an isometric view of the first mould support;

Figure 13 is an exploded view of the first mould support;

Figure 14 is a cross-sectional view of the first mould support showing suction pathways formed therein;

Figure 15 is an isometric view of a second robot adjacent two close and weld units and a monomer dispenser, as shown in Figure 1;

Figure 16; is a plan view of the arrangement shown in Figure 15;

Figure 17 is a side elevation of one of the close and weld units from Figure 15;

Figure 18 is an isometric view of a second end effector from the second robot, in a first configuration having the first mould support attached thereto;

Figure 19 is a plan view of the arrangement shown in Figure 18;

Figure 20 is an isometric view of the second end effector in a second configuration wherein the first mould support is detached; and

Figure 21 is a plan view of the arrangement shown in Figure 20.

Figures 1 to 21 show an embodiment of the invention.

Figure 1 shows a manufacturing system 1 for manufacturing contact lenses. The manufacturing system 1 includes: an injection moulding machine (IMM) 3; a first robot 5; a monomer dispensing unit 7; first and second close and weld units 9,11; a second robot 13 and a contact lens curing machine 15. The manufacturing system 1 also includes a computerised control system 17, for controlling operation of apparatus within the manufacturing system, and hence production of the contact lenses. The computerised control system 17 is illustrated diagrammatically in Figure 3. The computerised control system 17, synchronises operation of the IMM 3, first robot 5, monomer dispensing unit 7, first and second close and weld units 9,11, and the second robot 13. The computerised control system can comprise, for example at least one programmable logic controller, or can be a PC based control system.

The IMM 3 produces plastics contact lens moulds. Each mould comprises a cup-shaped male mould part and a cup-shaped female mould part. The IMM 3 comprises a “family” mould tool, which is a tool where a single impression of the tool produces both the male and female mould parts. In the example shown, the injection moulding tool is a twelve impression tool: one pattern of male impressions distributed about a pitch circle and a pattern of six female impressions distributed about a pitch circle. Accordingly the tool comprises a 2 x 6 impression tool.

Thus at the end of the injection moulding process, when the two halves of the tool are separated, one half of the tool has two sets of protrusions, each of which is arranged around its own pitch circle, with the male mould parts mounted on one set of protrusions and female mould parts mounted on the other set of protrusions. The female mould parts are cup-shaped and include a flange. The male mould parts are cup-shaped and include a flange. A contact lens mould is typically made up of one male part and one female part.

Each set of mould parts is connected together by webbing. The webbing is a by-product of the process, and is commonly referred to as “sprue”.

The first robot 5 is preferably in the form of a six axis robotic arm. However, it will be appreciated that other suitable forms of robot, which can produce the required functions of the first robot can be used, for example a five axis robot, or similar.

The first robot 5 includes a first end effector 19. The first end effector 19 is arranged to carry the set of male mould parts and the set of female mould parts. The first end effector 19 includes a part 21 that is fixed to the first robot 5. The fixed part 21 is typically attached to a wrist portion 23 of the first robot 5. The first end effector 19 also includes a detachable part. The detachable part comprises a first mould support 25. The first effector 19 has a first configuration wherein the first mould support 25 is releasably attached to the fixed part 21 of the first effector. The first configuration is best seen in Figures 6 and 7. The first end effector 19 has a second configuration in which the first mould support 25 is detached from the fixed part 21 of the first end effector. This is best seen in Figures 8 and 9.

The fixed part 21 includes an end effector body 27. The body 27 can be made from an assembly of parts, for example from steel plates connected together, for example welded and or bolted together, or may be made from a unitary construction, for example a cast body. The body 27 can be made from less dense materials such as aluminium to reduce weight. Preferably the body 27 includes an end plate 29, which is arranged to engage the wrist portion 23 of the first robot. The fixed part 21 includes attachment means for releasably attaching the first mould support 25 to the fixed part 21. The attachment means preferably comprises first and second electrically controllable magnets 31,33. The first support mould 25 is made from, or at least includes ferromagnetic material. The first and second electrically controllable magnets 31,33, when energised, fix the first mould support 25 to the fixed part 21 by means of magnetic attraction. When the first and second electrically controllable magnets 31,33 are in a non-energised state, the first mould support 25 can be removed from the fixed part 21. Typically the first and second electrically controllable magnets 31,33 include solenoids. Electrical power is supplied from a power supply unit 37 to the first and second electrically controllable magnets 31,33 via power cables 35. A controller 39 actuates the magnets by controlling energisation of the magnets 31,33 in accordance with signals received from the computer control system 17. The electromagnets 31,33 are arranged to engage the underside of the first mould support 25.

The fixed part 21 includes first, second and third pneumatic connectors, preferably in the form of suction cups 41,43,45. The suction cups 41,43,45 are part of a pneumatic circuit 47 that is arranged to selectively apply a negative pressure (suction) to the suction cups 41,43,45. Pneumatic circuit 47 includes a negative pressure source, such as a vacuum pump 49, vacuum switches 51, a controller 53 for controlling operation of the vacuum pump 49 and vacuum switches 51 in accordance with signals received from the control system 17, and pneumatic lines 55 which connect the suction cups 41,43,45 to the vacuum pump 49.

The first and second suction cups 41,43 are arranged to engage with first and second ports 57,59 located on an underside of the first mould support. This enables negative pressure to be applied to a manifold 61 in the first mould support 25. The third suction cup 45 connects to a third port 109.

It can be seen from Figures 8 and 9 that the first and second suction cups 41,43 are located towards a front end 65 of the fixed part 21. The first suction cup 41 is located on a first finger 67. The second suction cup 43 is located on a second finger 69. The first electromagnet 31 is located on the first finger 67 behind the first suction cup 41. The second electro-magnet 33 is located on the second finger 69 behind the second suction cup 43. A recessed area 71, is located between the first and second fingers 67,69. The third suction cup 45 is located centrally, substantially equidistant, between the first and second suction cups 41,43 in the width direction. However, it is positioned more rearward such that it is substantially in line with the first and second electromagnets 31,33.

First and second male locating formations, such as location pins 73,75, are located adjacent the first and second electromagnets 31,33 respectively. The first location pin 73 has a tapered upper end, with tapers forward and rearwards. The second locating pin 75 has a tapered upper end, with tapers sideways. The first and second locating pins 73,75 are arranged to engage with first and second female locating formations, such as bushes or bearings 77,79, located in holes 111,113 formed through the first mould support 25. The locating pins 73,75 and bushes or bearings 77,79 are arranged to very accurately locate the first mould support 25 onto the fixed part 21. The locating pins 73,75 are arranged substantially perpendicularly to an upper surface of the fixed part 21.

Features of the first mould support 25 are best seen in Figures 12 to 14. The first mould support includes a body 83. The body 83 comprises a plate, that can be made from materials such as aluminium or steel. If aluminium is used, the first mould support 25 includes some ferromagnetic material, such as small steel plates, for engagement with the magnets. A hole 85 is formed through the plate in a central region. An assembly 87 is mounted in the hole 85. The assembly 87 includes a body 89 and the manifold 61. The body 89 protrudes upwardly from an upper surface of the plate 83. The body includes six mould receiving formations in the form of six cylindrical recesses 95a-f arranged around a pitch circle in a substantially even manner. Each recess 95a-f includes a liner 97a-f, which is fixed in place by a respective bolt 99a-f. Each liner 97a-f is arranged to receive one of the female moulds. Each recess 95a-f includes a through-hole lOla-f towards its base. Three of the holes 101b,101c,lOld connect with a first air pathway 103 formed in the manifold 61. The first air pathway 103 connects the holes 101b,101c, lOld with the first port 57. Thus the recesses 95b,95c,95d have an air pathway connection to the first port 57.

Holes 101a,101e,101f are connected to a second air pathway 105 formed in the manifold 61. The second air pathway 105 connects the recesses 95a,95e,95f with the second port 59. A third air pathway 107 is formed in the manifold 61. The third air pathway connects the spring-loaded vacuum cup 63 with a third port 109. The spring-loaded vacuum cup 63 is arranged to apply a suction force to the sprue.

The first, second and third suction cups 41,43,45 are oriented in an upwards direction to engage the first, second and third ports 57,59,109 located on the underside of the first mould support respectively.

When the first mould support 25 is mounted onto the fixed part 21 of the first end effector, and the vacuum pump 49 is actuated, a negative pressure is applied to the interior of the recesses 95a-95f via the first and second air pathways 103,105. This has the effect of applying a suction force to the female moulds located therein. The suction force prevents the female moulds from falling out of the first mould support 25 when the first mould support is moved. The third suction cup 45 engages with third port 109 when the first mould support 25 is attached to the fixed part 21. Thus a negative pressure is applied to the spring-loaded vacuum cup 63, which enables it to provide a suction force to the sprue.

The body 83 includes a second pair of holes 115,117 formed through the plate 83 towards a front edge 119. Female locating formations in the form of bushes or bearings 121,123 are located in each of the holes 115,117 respectively. As mentioned previously, the bushes or bearings 77,79 are arranged to engage the first and second locating pins 71,75 respectively on the fixed part 21. The bushes or bearings 121,123 are arranged to engage with respective locating pins 175,177, which are part of a second end effector 125 on the second robot 13. Holes 127,129 are formed through the plate 83 towards left and right side edges 131,133. Female locating formations such as bushes or bearings 135,137 are located in the holes 131,133 respectively. Bushes or bearings 135,137 are arranged to engage with respective locating members 185,187 in the close and weld units 9,11.

The fixed part 21 includes a second mould support 139 located on an upper part 141 of the fixed part 21. The second mould support 139 is arranged to support six male mould parts. The second mould support 139 includes a central assembly 143 comprising a plate-like body 145. The body 145 includes six mould receiving formations in the form of six cylindrical recesses 147a-47f. Each recess 147a-147f includes a liner 149a-149f which is arranged to receive one of the male moulds. The cylindrical recesses 147a-147f, and hence liners 149a-149f are arranged around a pitch circle in a substantially even manner. Each liner 149a-149f comprises a plastics body. The mould assembly 143 includes a manifold 151, which has a similar arrangement to the manifold 61. The mould assembly 143 includes a spring-loaded vacuum cup 153 for releasably engaging sprue which connects the male moulds together.

Each of the recesses 147a-f and the spring-loaded vacuum cup 153 is connected to the pneumatic circuit 47 by pneumatic lines 155 thus a negative pressure can be applied to the male moulds located in the recesses 147a-f to prevent the male moulds from disengaging from the second mould support 139. The pneumatic circuit controller controls the application of the suction force according to signals received from the control system 17.

It will be apparent from the above description that when the first end effector 19 is in its first configuration with the first mould support 25 attached thereto, the first end effector 19 can be inserted into the IMM 3 to be loaded with a set of six female mould parts in the first mould support 25 and a set of six male mould parts in the second mould support 139. The suction force is used to disengage the male and female moulds from the IMM 3 tool and to locate the male and female moulds in the liners 97a-97f and 149a-149f respectively. The suction force is maintained during transit of the male and female moulds to one or more processing stations. When it is desirable to remove the male and female moulds from the first and second mould supports 25,139, the controller 53 either shuts off the vacuum pump 49 or actuates the vacuum switches 51 to remove the suction force applied to the male and female moulds.5.

At an appropriate stage in the manufacturing process, which is described below, the first robot 5 is arranged to release the first mould support 25. That is, the first mould support 25 is separated from the first robot 5. The first mould support 25 is subsequently releasably attached to the second robot 13. The second robot 13 is best seen in Figures 15, 16 and 17. The second robot 13 is preferably in the form of a six axis robotic arm. However, it will be appreciated that other types of robot can be used which can achieve similar movement patterns to the six axis robotic arm. The second robot 13 is arranged to remove the contact lens moulds from the end effector 25 and deposit them at the contact lens curing device 15. The second robot 13 moves the empty first mould support 25 to a temporary storage place, where it can be picked up by the first robot 5 to begin another manufacturing cycle. A suitable temporary storage place, may be, for example a rack located above one or more of the first and second close and weld units 9,11.

The second robot 13 includes the second end effector 125. Preferably the second end effector 125 is a simplified version of the first end effector 19, in that it does not include a second mould support 139, and its associated pneumatic lines. Thus the second end effector 125 can have a smaller overall size than the first end effector 19. The second end effector 125 is best seen in Figures 18 through to 21. Figures 18 and 19 show the second end effector 125 in a first configuration wherein the first mould support 25 is releasably attached thereto. Figures 20 and 21 show the second end effector in a second configuration wherein the first mould support 25 is detached from a part 157 of the second end effector that is fixed to the robot 13.

The fixed part 157 of the second end effector includes an end effector body 159. The body 159 includes an end plate 161 which is connected to a wrist portion 163 of the second robot 13. The fixed part 157 includes first and second electrically controllable magnets 165,167. The electrically controllable magnets 165,167 are part of a control circuit, which is similar to control circuit 36, and includes a controller 39, power supply unit 37, electrical cabling 35. The control circuit is arranged to selectively energise and de-energise the electrically controllable magnets 165,167 in a similar fashion to the magnets 31,33 in the first end effector 19. The magnets 165,167 are energised to attach the first mould support 25 to the fixed part 157. The magnets are de-energised in order to release the first mould support 25 from the fixed part 157.

The fixed part 157 includes pneumatic connectors in the form of first and second suction cups 169,171. The first and second suction cups 169,171 are part of a pneumatic circuit, which is similar to part of the pneumatic circuit 43, in that it includes a controller 53, vacuum pump 49, pneumatic lines 55, vacuum switches 51 and is arranged to provide a negative pressure to the recesses 95a-95f. The first suction cup 169 is arranged to engage with the first port 57 and the second suction cup 171 is arranged to engage with the second port 59.

The fixed part 157 includes first and second male locating formations in the form of locating pins 175,177. The first and second locating pins 175,177 are arranged to engage with bushes or bearings 121,123 to accurately locate the first mould support 25 onto to the fixed part 157.

The monomer dispensing unit 7 stores liquid monomer in a storage container. It includes a dispensing head, which is arranged to dispense liquid monomer into each of the female moulds, when the moulds are located beneath the head.

The cut and weld units 9,11 includes a head 179 which includes six tool members 181 arranged around a pitch circle similar to the second mould support 139. Each tool member 181 is arranged to receive and support a male mould thereon.

Each close and weld unit 9,11 includes a stand 183 which is arranged to receive and support the first mould support 25. Each close and weld unit 11,13 includes locating members 185,187 which are arranged to engage with bushes or bearings 135,137 to accurately locate the first mould support in the close and weld unit 9,11. When the first mould support 25 is properly located and secured by locating members 185,187 the head 179 is lowered towards the first mould support 25. This drives the male moulds into the female moulds, which contain monomer. Flanges of the male and female moulds are automatically tack-welded together thereby fastening the male mould to the female mould. A process of manufacturing a contact lens will now be described. • The IMM 3 produces the male and female moulds.

The IMM 3 tool separates leaving a set male of male mould parts sat on a first set of protrusions and a set of female mould parts sat on a second set of male protrusions. • First end effector 19 collects the male and female moulds.

The first robot 5 inserts the first end effector 19 into the IMM 3. The first end effector 19 is moved to a position wherein the first mould support 25 is located adjacent the female moulds. The recesses 95a-95f are located directly opposite respective female moulds. The second mould support 139 is located adjacent the male moulds. The recesses 147a-147f are each located directly opposite a respective male mould. The pneumatic circuit 47 is actuated and the female and male moulds are sucked into the first and second mould supports 25,139 respectively. • Sprue is removed from the mould parts.

The sprue from the injection moulding process is either deposited into a waste chute (gated sprue) or presented to a cropping station where it is cropped from the male moulds and female moulds and falls into a waste chute (non-gated sprue). The spring-loaded vacuum cups 63,153 are used to retain the sprue whilst transferring the sprue to the waste chute. • Monomer is dispensed into the female moulds.

The first robot 5 moves the first end effector 19 to the monomer dispensing unit 7. The first robot 5 positions the first mould support 25 below the dispensing unit 7. The monomer dispensing unit 7 is activated to dispense monomer into each of the female moulds. • Close and weld process.

The first robot 5 moves the first end effector 19 to one of the close and weld units 9,11. The second mould support 139 is moved directly beneath the head 179. The first robot 5 moves the second mould support 139 upwards such that male moulds are moved into engagement with tools 181. The suction force is reduced/cut and the male moulds are retained on the tool members 181.

The first robot 5 then moves the first mould support 25 so that it is positioned on stand 183. The electrically controllable magnets 31,33 are de-energised and the first mould support 25 is detached from the fixed part 21 of the first end effector, and hence from the first robot 5. The first robot 5 then moves to pick up a new first mould support 25 from a temporary storage station in order to start a new cycle of collecting male and female moulds.

The close and weld unit 9,11 is actuated to move locating members 185,187 into engagement with bushes or bearings 135,137. This accurately locates the first mould support 25 on the stand 183. The head 179 is lowered towards the first mould support 25 such that the male moulds are moved into the female moulds thereby causing the monomer to form a contact lens shape between the male and female moulds. The close and weld units 9,11 tack weld the mould flanges together.

After the male and female moulds have been tack welded together, the head 179 is moved upwards out of engagement with the male moulds. The male and female moulds remain located in the first mould support 25. The locating members 185,187 are raised and disengage the bushes or bearings 135,137. • First mould support 25 is attached to the second robot 13.

The second robot 13 moves the second end effector 125 into engagement with the first mould support 25. This involves the locating pins 175,177 engaging with bushes or bearings 121,123 to accurately locate the first mould support 25 onto the fixed part 157. The magnets 165,167 are energised by the electrical circuit and the first mould support 25 is attached to the fixed part 157. Vacuum suction is applied to the contact lens moulds via the first and second suction cups 169,171. • The second robot 13 moves the contact lens moulds to the contact lens curing machine 15.

The second robot 13 removes the contact lens moulds from the end effector and places them on to a conveyor in the curing machine 15, where the contact lens are cured. • First mould support 25 moved to a storage facility.

The second robot 13 then takes the first mould support 25 to a temporary storage facility, where it can be picked up by the first robot 5 when commencing a new cycle. When the first robot 5 collects a first mould support 25, the locating pins 73,75 engage with bushes or bearings 77,79 to accurately locate the first mould support 25 onto fixed part 21. This is very important since accurate placement of the first mould support in the IMM 3 to collect the female moulds is required. The tolerance is of the order of 0.1mm. Therefore it is imperative that the first mould support 25 is accurately located on the fixed part 21. In order to fix the first mould support 25 to the fixed part 21 the electromagnets 31,33 are energised.

It will be appreciated from the above discussion, that first mould supports 25 are exchanged between the first and second robots 5,13, and at times are not attached to either robot 5,13. This enables higher utilization of the robots, and can improve throughput. In some arrangements, it will be appreciated that the number of first mould supports 25 used in the manufacturing system may be greater than the number of robots 5,13 located in the manufacturing cell.

It will also be appreciated that the robots 5,13 can move the first mould supports 25 to other process stations, for example to print heads, where layers of ink can be applied to the female mould without restricting the cycle time in the system.

Although the present invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Furthermore, it will be apparent to the skilled person that modifications can be made to the above embodiment that fall within the scope of the invention.

For example, the first mould support can be fixedly attached to the end effector body and the end effector body can be releasably attached to the robotic arm. The wrist portion of the robotic arm may include attachment means, for example a magnetic coupling device for selectively attaching and detaching the end effector to the robot. One of the robot and the end effector can include a male coupling formation such as a locating pin and the other of the robot and end effector can include a female coupling formation, which is arranged to receive the locating pin. In this arrangement the entire, or at least a substantial part, of the end effector is detached from the robot during a contact lens manufacturing process.

It will be appreciated that attachment means other than magnetic coupling devices can be used, for example an arrangement of electro-mechanically operated latches can be used to selectively attach and detach the first mould support to the end effector, or attach and detach the end effector to the robot during a contact lens manufacturing process.

The attachment means can include a different number of controllable magnets, such as one magnet, three magnets, or four magnets, etc.

The end effectors can include a different number of pneumatic connectors. The end effectors include at least one pneumatic connector, and preferably a plurality of pneumatic connectors.

Each mould support 25, 139 can include a different number of recesses and liners, from the embodiment above. This is to accommodate larger or smaller sets of male and female mould parts. Typically the number of recesses in the first mould support matches the number of recess in the second mould support. Typically each mould support includes between 4 and 12 recesses. Any practicable number of recesses can be included. The pneumatic circuit is adapted accordingly.

While the first support member includes female locating formations, such as bushes or bearings, and the fixed parts of the end effectors include male locating formations such as locating pins, it will appreciated that the arrangement can be reversed, or a mixture of male and female locating formations can be used.

The manufacturing system can include a different number of robots. Preferably the manufacturing system includes at least one robot per manufacturing cell. Preferably the manufacturing system includes a plurality of robots per manufacturing cell.

Additional processing stations can be included in the manufacturing cell, of a similar type to those described above, or of a different type.

Claims (34)

Claims

1. An end effector for a robot in a contact lens manufacturing process, said end effector including: a first mould support having a plurality of mould receiving formations wherein each mould receiving formation is arranged to receive and support a contact lens mould, or at least a part thereof; and attachment means arranged to attach the first mould support to the robot and/or detach the first mould support from the robot, during a contact lens manufacturing process, wherein the attachment means includes an actuator arranged to receive control signals from a control system, and in response to said control signals is arranged to selectively attach the first mould support to the robot and/or detach the first mould support from the robot, wherein the first mould support includes ferromagnetic material and the actuator comprises at least one controllable magnetic device for selectively attracting the first mould support to the at least one magnetic device.

2. An end effector according to claim 1, including a body for connecting the first mould support to the robot.

3. An end effector according to claim 2, wherein the attachment means is arranged to rclcasably attach the first mould support to the end effector body.

4. An end effector according to claim 2 or 3, wherein the attachment means is arranged to releasably attach the end effector body to the robot.

5. An end effector according to any preceding claim, wherein the mould receiving formations are arranged around a pitch circle.

6. An end effector according to any preceding claim, wherein at least some of the mould receiving formations include a liner.

7. An end effector according to any preceding claims, wherein at least one of the mould receiving formations is connected to a first air pathway formed in the first mould support, which is part of a pneumatic system, said pneumatic system being arranged to selectively apply a negative pressure to the at least one mould receiving formation via the first air pathway.

8. An end effector according claim 7, wherein the first air pathway includes a first port, and including a first pneumatic connector arranged to releasably connect with the first port.

9. An end effector according to claim 8, wherein at least one of the mould receiving formations is connected to a second air pathway formed in the first mould support, which is part of the pneumatic system, said second air pathway including a second port, and including a second pneumatic connector for releasably connecting with the second port, wherein the pneumatic system is arranged to selectively apply a negative pressure to at least one of the mould receiving formations via the second air pathway.

10. An end effector according to any one of the preceding claims, wherein the first mould support includes a spring loaded vacuum cup for applying a suction force to sprue attached to the contact lens moulds.

11. An end effector according to claim 10, including a third air pathway formed in the first mould support, the spring loaded vacuum cup is connected to the third air pathway, the third air pathway including a third port and, and a pneumatic connector for releasably connecting with the third port.

12. An end effector according to any one of the preceding claims, wherein one of the first support mould and the end effector body includes a first male locating formation and the other of the first support mould and the end effector body includes a first female locating formation.

13. An end effector according to claim 12, wherein one of the first support mould and the end effector body includes a second male locating formation and the other of the first support mould and the end effector body includes a second female locating formation.

14. An end effector according to claim 12 or 13, wherein the first mould support includes at least one additional locating formation for accurately locating the first mould support onto an end effector body.

15. An end effector according to any one of the preceding claims, including at least one locating formation for accurately locating the position of the first mould support with respect to a manufacturing station.

16. An end effector according to anyone of the preceding claims, including a second mould support arranged to support a plurality of contact lens moulds, or parts thereof.

17. An end effector according to claim 16, wherein the second mould support is attached to the end effector body.

18. An end effector according to claim 16 or 17, wherein the second mould support includes a plurality of mould receiving formations, wherein each mould receiving formation is arranged to receive a contact lens mould, or part thereof.

19. An end effector according to any one of claims 16 to 18, wherein each mould receiving formation is connected to at least one air pathway, which is part of a pneumatic system, said pneumatic system being arranged to selectively apply a negative pressure to the mould receiving formation.

20. An end effector according claim 19, wherein the second mould support includes at least one air pathway port for connecting the at least one mould receiving formation to the pneumatic system.

21. A robot including an end effector according to any one of the preceding claims.

22. A robot according to claim 21, wherein the arm comprises an articulated arm.

23. A manufacturing system for manufacturing contact lenses including a first robot according to claim 21 or 22.

24. A manufacturing system according to claim 23, including a second robot according to claim 21 or 22.

25. A manufacturing system according to claim 23 or 24, including at least one of the following: an injection moulding machine for producing contact lens male and female mould parts; a sprue waste chute; a dispensing unit for dispensing liquid plastic into the contact lens moulds; at least one close and weld unit; a printing unit; intermediate storage locations for receiving at least one first mould support; a contact lens curing unit; or any combination thereof; and a control system for controlling operation of the manufacturing system.

26. A process for manufacturing contact lenses, including: providing a first robot according to claim 21 or 22; releasably attaching a first mould support to the first robot; the first mould support receiving a batch of contact lens moulds, or parts thereof; transporting the first mould support to a first processing station; and detaching the first mould support from the first robot.

27. A process according to claim 26, including providing a second robot according to claim 24 or 25.

28. A process according to claim 27, including releasably attaching the first mould support to the second robot.

29. A process according to any one of claims 26 to 28, including releasably attaching a new first mould support to the first robot; the new first mould support receiving a batch of contact lens moulds, or parts thereof; transporting the new first mould support to the first processing station, or a different processing station; and detaching the new first mould support from the robot.

30. A process according to claim 28 or 29, including the second robot moving the first mould support to a second processing station.

31. A process according to any one of claims 28 to 30, including detaching the first mould support from the second robot.

32. A process according to any one of claims 28 to 31, including the second robot moving the first mould support to a storage location; and releasably attaching the first mould support to the first robot.

33. A process according to claim 32, when dependent on claim 29, including releasably attaching the new first support mould to the second robot.

34. A process according to any one of claims 26 to 33, wherein each processing station comprises one of the following: an injection moulding machine for producing contact lens male and female mould parts; a sprue waste chute; a dispensing unit for dispensing liquid plastic into the contact lens moulds; at least one close and weld unit; a printing unit; intermediate storage locations for receiving at least one first mould support; an contact lens curing unit.