U.S. patent application number 17/199110 was filed with the patent office on 2021-10-14 for manufacturing module for the manufacture of ophthalmic lenses.
The applicant listed for this patent is ALCON INC.. Invention is credited to Roger Biel, Peter Hagmann, Axel Heinrich, Stephan Pirl, Shu Zong.
Application Number | 20210318468 17/199110 |
Document ID | / |
Family ID | 1000005678757 |
Filed Date | 2021-10-14 |
United States Patent
Application |
20210318468 |
Kind Code |
A1 |
Zong; Shu ; et al. |
October 14, 2021 |
MANUFACTURING MODULE FOR THE MANUFACTURE OF OPHTHALMIC LENSES
Abstract
A manufacturing module (MM) for contact lenses comprises a
plurality of manufacturing stations (300, 301, 302, 310, 320, 321,
322, 330, 331, 340, 341, 342, 350, 351, 352) arranged in a closed
loop and a plurality of lens mold carriers (1, 2) which are
transported through the manufacturing stations. Each lens mold
carrier (1, 2) comprises a frame (10, 20) having a predetermined
number of mounting sites (100, 200) arranged along the frame. Each
lens mold carrier (1, 2) further comprises a predetermined number
of molds (112, 212) removably mounted to the frame (10, 20) at the
mounting sites (100, 200), the molds being reusable male or female
molds (212, 112). Two lens mold carriers (1, 2) are assigned to
each other to form a pair, so that upon mating the pair of lens
mold carriers (1, 2) the male and female molds (212, 112) are mated
to form mold cavities defining the shape of the lenses. The
manufacturing stations comprise a mold changing station (300, 301,
302) configured to be capable of removing a mold from its mounting
site (100, 200) and mounting a different mold at the said mounting
site (100, 200), or configured to change the rotational position of
a mold (112, 212) mounted to the frame (10, 20), or both.
Inventors: |
Zong; Shu; (Cumming, GA)
; Hagmann; Peter; (Waldburg, DE) ; Biel;
Roger; (Aschaffenburg, DE) ; Heinrich; Axel;
(Aschaffenburg, DE) ; Pirl; Stephan; (Rudenau,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ALCON INC. |
Fribourg |
|
CH |
|
|
Family ID: |
1000005678757 |
Appl. No.: |
17/199110 |
Filed: |
March 11, 2021 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
16109080 |
Aug 22, 2018 |
10983251 |
|
|
17199110 |
|
|
|
|
62549558 |
Aug 24, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 2035/0827 20130101;
B29D 11/00442 20130101; G02C 7/028 20130101; B29D 11/0048 20130101;
B29D 11/0025 20130101; G02B 1/043 20130101; B29D 11/00182 20130101;
B29D 11/00173 20130101; B29D 11/0023 20130101; B29L 2011/0041
20130101; B29D 11/00509 20130101; B29D 11/00125 20130101; B29D
11/00259 20130101; G02C 7/027 20130101 |
International
Class: |
G02B 1/04 20060101
G02B001/04; B29D 11/00 20060101 B29D011/00; G02C 7/02 20060101
G02C007/02 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. Manufacturing module for the manufacture of contact lenses,
comprising a plurality of manufacturing stations a male mold
exchange station (300), a female mold exchange station (301), a
dosing station (320), a closing station (321), a curing station
(330), a mold opening station (340), and a removal station (342),
wherein the plurality of manufacturing stations of the
manufacturing module (MM) are grouped to form a plurality of
individual manufacturing units comprising a first individual
manufacturing unit (30); a second individual manufacturing unit
(32); a third individual manufacturing unit (33); a fourth
individual manufacturing unit (34) arranged in a closed loop, and
wherein the manufacturing module further comprises a plurality of
transfer robots (36), each transfer robot (36) of the plurality of
transfer robots being arranged at a location between two individual
manufacturing units of the plurality of individual manufacturing
modules and being configured to transfer the lens mold carriers
from one of the two individual manufacturing units between which
the respective transfer robot is arranged to the other one of the
individual manufacturing units between which the respective
transfer robot is arranged.
9. Manufacturing module according to claim 8, wherein a first
individual manufacturing unit (30) of the plurality of
manufacturing units comprises the male mold exchange station (300),
and the female mold exchange station (301), a second individual
manufacturing unit (32) of the plurality of manufacturing units
comprises a dosing station (320) for dosing a lens forming material
into the male or female molds, a closing station (321) for mating
the assigned pairs of lens mold carriers, a third individual
manufacturing unit (33) comprises a curing station (330) for curing
the lens forming material to form lenses, a fourth individual
manufacturing unit (34) comprises a mold opening station (340) for
separating the assigned pairs of lens mold carriers and a removal
station (342) for removing the lenses from the molds and for
transporting them away from the manufacturing module.
10. (canceled)
11. Production line (PL) for the production of contact lenses,
comprising a manufacturing module (MM) according to claim 8, and
further comprising an extraction and treatment module (EM) for the
extraction of unwanted substances from the lenses and for chemical
treatment of the lenses, an inspection module (IM) for the
inspection of the extracted and chemically treated lenses, and a
packaging module (PP) for packaging the lenses that have been
identified by the inspection module (IM) as being acceptable.
12. Method of producing contact lenses, the method comprising
manufacturing a plurality of lenses in a closed-loop manufacturing
process in which different lots of lenses are simultaneously
manufactured in a manufacturing module (MM) according to claim 8,
the method comprising the steps of: dispensing a lens forming
material into the female molds (112) of one lens mold carrier (1)
of the respective pair of lens mold carriers or into the male molds
(212) of the other lens mold carrier (2) of the respective pair of
lens mold carriers, mating the two lens mold carriers of the
respective pair of lens mold carriers to form the mold cavities
with the lens forming material being enclosed in the mold cavities
formed between the male and female molds, curing the lens forming
material in the mold cavities to form the contact lenses,
separating the two mated lens mold carriers of the respective pair
of lens mold carriers, removing the contact lenses from the male or
female molds, in the mold changing station, removing at least one
mold from its mounting site on one of the two lens mold carriers of
the respective pair of lens mold carriers and mounting a different
mold to the said mounting site, or changing the rotational position
of at least one of the molds mounted to the two lens mold carriers
(11, 21) of the respective pair of lens mold carriers, or both.
13. Method according to claim 12, wherein in the mold changing
station a said male mold (212) is removed from its mounting site
(200) on the lens mold carrier (2) and a different male mold is
mounted to the said mounting site (200).
14. Method according to claim 12, wherein in the mold changing
station a said female mold (112) is removed from its mounting site
(100) on the lens mold carrier (1) and a different female mold is
mounted to the said mounting site (100).
15. Method according to claim 12, wherein in the mold changing
station (300, 301, 302) the rotational position of a said male or
female mold (212, 112) is changed while the said male or female
mold remains mounted to the lens mold carrier.
Description
[0001] This application claims the benefit under 35 USC .sctn. 119
(e) of U.S. provisional application No. 62/549,558 filed 24 Aug.
2017, incorporated by reference in its entirety.
[0002] The invention relates to a manufacturing module for the
manufacture of ophthalmic lenses, in particular contact lenses such
as soft contact lenses.
[0003] The manufacture of ophthalmic lenses, in particular contact
lenses such as soft contact lenses, is typically carried out in
fully automated production lines where the contact lenses are
produced in high numbers. In particular, contact lenses which are
worn only once and which are disposed of after being worn need to
be produced in very high numbers. Such contact lenses are produced,
for example, in a closed-loop process with the aid of re-usable
lens molds made of glass which are used many times to produce the
high number of contact lenses.
[0004] As regards the manufacture of the contact lenses, each mold
typically comprises male and female mold halves which, upon being
mated and closed, together form a mold cavity between them defining
the geometry of the contact lens to be formed. Initially, a lens
forming material is dispensed into one of the mold halves, for
example into the female mold half, prior to the mold halves being
mated. For the sake of simplicity, in the following it will only be
referred to male molds and female molds rather than to male mold
halves and female mold halves. After dispensing of the lens forming
material into the female mold, the male and female molds are mated
and closed, and the lens forming material enclosed in the mold
cavity is polymerized and/or crosslinked to form the contact lens.
Thereafter, the mold is opened again by separating the male and
female molds, the contact lens is removed from either the male mold
or the female mold, and the contact lens is then advanced for being
further processed.
[0005] For example, in case the contact lens is a silicone hydrogel
contact lens, solvents contained in the lens forming material which
are also contained in the contact lens formed therefrom as well as
any non-polymerized and/or non-crosslinked lens forming material
need to be extracted from the contact lens. Also, a coating can be
applied to the contact lens in order to improve lubricity of the
contact lens to increase comfort when the contact lens is worn on
the eye. For these purposes, the contact lenses may be transported
through different baths (extraction baths, water baths, coating
baths) before the extracted and coated contact lens is further
advanced for getting inspected.
[0006] Inspection of the contact lens is then performed and may
comprise an inspection for defects of the contact lens such as
bubbles, inclusions, edge defects, other cosmetic defects, etc.,
but may in addition also comprise measurement of the optical
characteristics and the central thickness of the contact lens.
[0007] Once the contact lens has successfully passed inspection it
is advanced to the primary packaging station where it is placed
into a packaging shell. Packaging liquid is then dispensed into the
packaging shell, and a foil is placed onto the shell and is
heat-sealed thereto.
[0008] As regards the molds used in the manufacture of the contact
lens, once the contact lens has been removed the male and female
molds are cleaned, rinsed and dried and are then re-used to
manufacture the next contact lens in the manner described
above.
[0009] In the manufacture of contact lenses, typically a number of
lots of contact lenses are produced on the production line at the
same time with the aid of a plurality of lens mold carriers which
are transported through the manufacturing stations of the
production line. Each lens mold carrier comprises a frame having a
predetermined number of mounting sites arranged at predetermined
locations along the frame (for example fourteen mounting sites),
and these predetermined number and locations of the mounting sites
are identical for each lens mold carrier. Each lens mold carrier
further comprises a predetermined number of mold units (for example
fourteen mold units), which are removably mounted to the lens mold
carrier, and each mold unit comprises either a reusable male mold
or a reusable female mold. However, all molds of one lens mold
carrier are of the same type, i.e. either all of them are male
molds or all of them are female molds. Two lens mold carriers (one
male lens mold carrier and one female lens mold carrier) of the
plurality of lens mold carriers are assigned to each other to form
pairs of lens mold carriers. Accordingly, at the mounting sites of
one of the lens mold carriers of a pair of lens mold carriers male
molds are arranged while at the mounting sites of the other lens
mold carrier of a pair of lens mold carriers female molds are
arranged, so that upon mating the lens mold carriers of the pairs
the respective male and female molds are mated in order to form
mold cavities defining the shape of the contact lenses to be
manufactured.
[0010] By way of example, one lens mold carrier may be equipped
with seven pairs of molds (fourteen molds in total), with the two
molds of one pair being identical and being mounted to the frame at
adjacently arranged locations (i.e. the first pair of molds is
arranged at mounting locations number one and two, the second pair
of molds is arranged at mounting locations number three and four,
and so on), so that with one carrier it is possible to manufacture
seven pairs of contact lenses with different geometries, i.e. seven
different lots at the same time (each of the seven pairs of molds
forming a different lot). Each individual lens mold carrier of the
plurality of lens mold carriers on the production line is equipped
with the same molds in the same sequence, that is to say each
individual lens mold carrier of the plurality of lens mold carriers
on the production line is equipped with the same molds at the same
mounting locations of the respective carrier. As a result, for
example, contact lenses manufactured with the molds of the first
pair (i.e. the mold halves at mounting location number one and
mounting location number two of each of the lens mold carriers)
always have the same geometries. This also holds for the other
pairs (lots).
[0011] Before starting manufacturing, configuration of each of the
individual lens mold carriers is performed off-line (each of the
lens molds carriers is equipped at the individual mounting
locations with the same molds in the same sequence). The lens mold
carriers are then placed on the production line. Thereafter,
manufacturing of the seven lots of contact lenses is performed for
many hours. Accordingly, once the lens mold carriers are placed on
the production line it is only possible to manufacture the same
seven lots of contact lenses during these many hours. In case each
individual mounting location on the lens mold carrier represents an
individual lot, then it is possible to manufacture fourteen
different lots at the same time, this being the maximum number of
lots that can be manufactured during these many hours.
[0012] This is an efficient manner to produce high numbers of
contact lenses having a base curve radius selected from a certain
range of base curve radii and having an optical power that is
selected from a certain range of optical powers. For example,
within the said certain range of base curve radii contact lenses
are produced at steps of, for example, 0.1 millimeter (mm)
difference in base curve radius. And for each individual base curve
radius within the said range of base curve radii, contact lenses
having optical powers within the said certain range of optical
powers are produced at steps of, for example, 0.25 diopter (dpt)
difference in optical power. For each such combination of base
curve radius and optical power the market requires a high number of
contact lenses, as there is a high number of contact lens wearers
in the population requiring contact lenses having these
combinations of base curve radii and optical powers. Accordingly,
production of a high number of contact lenses through the
above-described process is very efficient.
[0013] After the above-described manufacture of contact lenses has
been performed for many hours, operation of the production line is
interrupted and a line clearance is performed, i.e. the lens mold
carriers are removed from the production line. New lens mold
carriers which have been configured off-line and which may (or may
not) be equipped with mold halves different from those that have
been used before are then placed on the production line. A number
of sample contact lenses must then be produced, and only after
these sample contact lenses have been produced and inspected and
have been found to have the required specifications, operation of
the production line is resumed. This is a laborious and
time-consuming process with very considerable downtime of the
production line during which no contact lenses can be produced.
[0014] In case smaller lots of contact lenses having the same
properties are required by the market (contact lenses having
combinations of base curve radius and optical power for which only
smaller numbers of contact lens wearers exist in the population)
this process is open to improvement, since the downtime of the
production line (i.e. the time during which the previous lens mold
carriers are removed from the production line and during which the
new lens mold carriers are placed on the production line) is very
considerable. While downtime of the production line is generally
unwanted it is to some extent acceptable for larger lots (i.e. high
numbers of contact lenses to be produced, for example many
thousands of contact lenses). However, downtime of the production
line strongly affects efficiency in case smaller lots (for example
only a few hundreds of contact lenses) are to be produced.
[0015] It is therefore an object of the invention to overcome the
afore-mentioned disadvantages and to suggest an apparatus and
method allowing for an efficient production also of smaller lots of
lenses.
[0016] This object is achieved through a manufacturing module,
through a production line comprising such manufacturing module, and
through a method of producing ophthalmic lenses as they are
specified by the features of the respective independent claim.
[0017] In particular, as regards the manufacturing module the
object is achieved by a manufacturing module for the manufacture of
ophthalmic lenses, in particular contact lenses such as soft
contact lenses, comprising a plurality of manufacturing stations
arranged in a closed loop and a plurality of lens mold carriers
which are transported through the manufacturing stations arranged
in the closed loop.
[0018] Each lens mold carrier comprises a frame having a
predetermined number of mounting sites arranged at predetermined
locations along the frame, the predetermined number and locations
of the mounting sites being identical for each lens mold carrier of
the plurality of lens mold carriers.
[0019] Each lens mold carrier further comprises a predetermined
number of molds corresponding to the predetermined number of
mounting sites of the frame, with the molds being removably mounted
to the frame at the mounting sites, and with all molds of a said
lens mold carrier either being reusable male molds or with all
molds of the said lens mold carrier being reusable female
molds.
[0020] Two lens mold carriers, respectively, of the plurality of
lens mold carriers are assigned to each other to form a pair of
lens mold carriers in a manner such that for each pair of lens mold
carriers at the mounting sites of one lens mold carrier of a said
pair reusable male molds are arranged, while at the mounting sites
of the other lens mold carrier of the said pair reusable female
molds are arranged, so that upon mating the two lens mold carriers
of the said pair of lens mold carriers the respective reusable male
and female molds are mated to form mold cavities defining the shape
of the lenses to be manufactured.
[0021] The manufacturing stations comprise a mold changing station,
the mold changing station being configured to be capable of
removing a said mold from its mounting site on the frame of a said
lens mold carrier and mounting a different mold to the frame at the
said mounting site, or being configured to change the rotational
position of a said mold mounted to the frame of a said lens mold
carrier, or both.
[0022] According to one aspect of the manufacturing module
according to the invention, the mold changing station comprises a
male mold exchange station for removing a said male mold from its
mounting site on the frame of a said lens mold carrier, and for
mounting a different male mold to the said mounting site.
[0023] According to a further aspect of the manufacturing module
according to the invention, the mold changing station comprises a
female mold exchange station for removing a said female mold from
its mounting site on the frame of a said lens mold carrier, and for
mounting a different female mold to the said mounting site.
[0024] According to still a further aspect of the manufacturing
module according to the invention, the mold changing station
comprises a toric axis setting station for changing and setting the
rotational position of a said male or female mold mounted to the
lens mold carrier.
[0025] Yet in accordance with another aspect of the manufacturing
module according to the invention, the manufacturing module is
further configured to assign to each lens a unique lens
identification code which is representative of the type of lens at
least for a predetermined period of time.
[0026] In accordance with a further aspect of the manufacturing
module according to the invention, the manufacturing module further
comprises a printing station, wherein the printing station is
configured to print the unique lens identification code to one of
the reusable male and female molds.
[0027] According to a further aspect of the manufacturing module
according to claim the invention, the printing station is an inkjet
printing station.
[0028] According to still a further aspect of the manufacturing
module according to the invention, the manufacturing stations are
grouped to form a plurality of individual manufacturing units
arranged in a closed loop, with the individual manufacturing units
of the plurality of individual manufacturing units comprising a
plurality of the manufacturing stations. The manufacturing module
further comprises a plurality of transfer robots, each transfer
robot of the plurality of transfer robots being arranged at a
location between two individual manufacturing units of the
plurality of individual manufacturing modules and being configured
to transfer the lens mold carriers from one of the two individual
manufacturing units between which the respective transfer robot is
arranged to the other one of the individual manufacturing units
between which the respective transfer robot is arranged.
[0029] According to yet a further aspect of the manufacturing
module according to the invention, [0030] a first individual
manufacturing unit of the plurality of manufacturing units
comprises the male mold exchange station, the female mold exchange
station, and the toric axis setting station, [0031] a second
individual manufacturing unit of the plurality of manufacturing
units comprises a dosing station for dosing a lens forming material
into the male or female molds, a closing station for mating the
assigned pairs of lens mold carriers, and a forming station for
moving the individual molds formed by the mated lens mold carriers
to an intermediate closed position, [0032] a third individual
manufacturing unit comprises a curing station for curing the lens
forming material to form lenses, in particular a UV-light station,
and a relative mold movement station configured to perform a
relative movement of the male and female molds from the
intermediate closed position to a final closed position during
curing of the lens forming material, [0033] a fourth individual
manufacturing unit comprises a mold opening station for separating
the assigned pairs of lens mold carriers, a rinsing station for
rinsing away any excess lens material from the molds, and a removal
station for removing the lenses from the molds and for transporting
them away from the manufacturing module, and [0034] a fifth
individual manufacturing unit comprises a mold cleaning station, a
mold rinsing station, and a mold drying station.
[0035] In accordance with a further aspect of the manufacturing
module according to the invention, the inkjet printing station is
arranged between the first individual manufacturing unit and the
second individual manufacturing unit.
[0036] Another aspect of the invention is directed to a production
line for the production of ophthalmic lenses, in particular contact
lenses such as soft contact lenses. The production line comprises a
manufacturing module as described above, and further comprises an
extraction and treatment module for the extraction of unwanted
substances from the lenses and for chemical treatment of the
lenses, an inspection module for the inspection of the extracted
and chemically treated lenses, and a packaging module for packaging
the lenses that have been identified by the inspection module as
being acceptable.
[0037] Still another aspect of the invention is directed to a
method of producing ophthalmic lenses, in particular contact lenses
such as soft contact lenses, the method comprising manufacturing a
plurality of lenses in a closed-loop manufacturing process in which
different lots of lenses are simultaneously manufactured in a
manufacturing module as described above.
[0038] The method comprises the steps of: [0039] dispensing a lens
forming material into the female molds of one lens mold carrier of
the respective pair of lens mold carriers or into the male molds of
the other lens mold carrier of the respective pair of lens mold
carriers, [0040] mating the two lens mold carriers of the
respective pair of lens mold carriers to form the mold cavities
with the lens forming material being enclosed in the mold cavities
formed between the male and female molds, [0041] curing the lens
forming material in the mold cavities to form the ophthalmic
lenses, [0042] separating the two mated lens mold carriers of the
respective pair of lens mold carriers, [0043] removing the
ophthalmic lenses from the male or female molds, [0044] in the mold
changing station, removing at least one mold from its mounting site
on one of the two lens mold carriers of the respective pair of lens
mold carriers and mounting a different mold to the said mounting
site, or changing the rotational position of at least one of the
molds mounted to the two lens mold carriers of the respective pair
of lens mold carriers, or both.
[0045] According to one aspect of the method according to the
invention, in the mold changing station a said male mold is removed
from its mounting site on the lens mold carrier and a different
male mold is mounted to the said mounting site.
[0046] According to a further aspect of the method according to the
invention, in the mold changing station a said female mold is
removed from its mounting site on the lens mold carrier and a
different female mold is mounted to the said mounting site.
[0047] In accordance with yet another aspect of the method
according to the invention, in the mold changing station the
rotational position of a said male or female mold is changed while
the said male or female mold remains mounted to the lens mold
carrier.
[0048] The mold changing station of the manufacturing module allows
for a mold exchange, i.e. it allows for a removal of a mold from
its mounting site on the frame and for mounting of a different mold
to the frame at the said mounting site, while the lens mold carrier
remains on the production line. A different mold in this regard is
to be understood such that it is different in at least one
geometrical property (for example the base curve radius or the
front curve radius, depending on whether it is a male mold or a
female mold). A line clearance, i.e. a complete interruption of the
production line, removal of all lens mold carriers from the
production line in order to be able to subsequently place new lens
mold carriers on the production line carrying different molds, and
the subsequent production of sample lenses etc., is no longer
required to perform the change. Since the mold exchange station is
one of the stations of the manufacturing module which are arranged
in the closed loop, it is possible to perform the exchange of the
mold while production keeps on running. It is thus possible to
start production of a new lot of contact lenses without the need to
interrupt production ("lot change on the fly"), thus leading to a
high increase in flexibility and production efficiency.
[0049] Only by way of example, let us assume that the
above-described lens mold carriers are used, with each carrier
comprising the frame having the fourteen mounting sites, and that
for each of the lens mold carriers transported through the
manufacturing stations of the manufacturing module at the same
mounting site the same type of mold (i.e. male or female) is
mounted to the frame (and this includes that fourteen different
molds may be mounted to each mold carrier, but the arrangement of
the molds is the same for all mold carriers). If a lot change is to
be performed, in the mold changing station the mold mounted to the
frame of the respective lens mold carrier at let us say mounting
site number one is removed from the frame of the respective lens
mold carrier and a new mold is mounted to the frame at the said
mounting site number one instead. Once the next lens mold carrier
enters the mold changing station, the same exchange operation is
performed at mounting site number one of the next lens mold
carrier, and so on, until the molds at mounting site number one of
all lens mold carriers transported through the manufacturing module
have been exchanged (although for lots smaller than the total
number of lens mold carriers transported through the manufacturing
module even that is not necessary). The lot change is then
completed.
[0050] Production of the new lot of lenses already starts once the
first lens mold carrier having the new mold mounted to the carrier
at mounting site number one reaches a dosing station arranged
downstream of the mold changing station where a lens forming
material is dosed into the mold. Since all subsequent lens mold
carriers reaching the dosing station have the same new mold
arranged at mounting site number one, too, production of the new
lot of lenses is continued until the next mold exchange is
performed at mounting site number one.
[0051] It goes without saying that the mold exchange described
above at mounting site number one of a lens mold carrier has been
described by way of example only. It is of course also possible to
change the molds at any other mounting site of the lens mold
carrier. Also, it is possible to exchange the molds at different
mounting sites of a lens mold carrier at the same time, for example
it is possible to exchange the molds at mounting sites number one
and three at the same time. It is even possible to exchange the
molds at each of the fourteen mounting locations at the same time,
meaning that production of fourteen new lots of lenses is started
at the same time. In the extreme, it is possible to produce lots
each consisting of one single lens only (meaning that all molds at
each of the mounting sites are always exchanged in the mold
exchange station), so that in the extreme the maximum number of
lots concurrently manufactured corresponds to the number of lens
mold carriers times the number of mounting sites per lens mold
carrier.
[0052] Alternatively, instead of performing a lot change on the fly
in the mold changing station by exchanging a mold (i.e. by removing
a mold from the frame at a particular mounting site and mounting a
new mold at the said particular mounting site), it is also possible
to perform a lot change on the fly by changing the rotational
position of the mold (in case the mold is not rotationally
symmetrical as this is the case e.g. in the production of toric
lenses). Change of the rotational position of the mold means, that
the mold is not removed from its mounting site on the frame of the
lens mold carrier but that the mold is only rotated while it
remains mounted to the frame of the lens mold carrier.
[0053] And although the mold is not exchanged, due to the mold not
being rotationally symmetrical a new lot of lenses is produced
after rotation of the mold. This can be easily understood when
glancing at toric lenses. For toric lenses, the two main axes of
the toric lenses are typically arranged perpendicular relative to
each other. If this arrangement of the two main axes is angularly
rotated (by rotating the mold) a different toric lens is produced
as the arrangement of the two main axes is different after rotation
(new toric axis setting), assuming that the other mold is not
rotated. Also, it is again possible to change the toric axis
setting of two or more molds at different mounting sites at the
same time, similar to what is discussed above with reference to the
mold exchange.
[0054] Of course, combinations of mold exchange and changes in
rotational position (toric axis setting) can be performed, i.e. a
new mold may be mounted to the frame at a particular mounting site
with the toric axis setting being different from the toric axis
setting of the mold that has been exchanged. Also, this can be
performed at different mounting sites of the lens mold carrier at
the same time.
[0055] As is evident, a lot change on the fly can be performed
either by exchanging a male mold in a male mold exchange station,
or by exchanging a female mold in a female mold exchange station,
or both. Toric axis setting (i.e. rotation of the male or female
mold) can be performed in a toric axis setting station.
[0056] Assigning a unique lens identification code to each lens of
the same type (e.g. the same optical power, the same base curve and
front curve radii, etc.), for example by printing a unique lens
identification code to one of the reusable male and female molds
using an inkjet printer so that the code will be transferred and
become part of the lens as the lens forming material is cured to
form the lens, allows for checking in an inspection module (by
reading the unique lens identification code) whether the lens
inspected actually is of the type represented by the respective
unique lens identification code. In addition, it allows for
checking whether the lens actually inspected is that lens which is
expected to be inspected at the respective time (i.e. whether the
lens actually inspected is the correct lens in the sequence of
lenses manufactured).
[0057] The lens identification code may be unique and is
representative of the type of contact lens during this
predetermined period of time. By way of example, the duration of
such predetermined period of time may be from one week to three
months. This means, that during this predetermined period of time
the same lens identification code cannot be used for a different
type of contact lens, however, after that predetermined period of
time is over, the same lens identification code can be used again,
even for a different type of contact lens. If the same lens
identification code is used again, it is again unique and
representative for this different type of contact lens for the next
predetermined period of time.
[0058] Alternatively, the lens identification code may be unique
and is representative for the type of contact lens not only for a
predetermined period of time, but may be representative for this
type of contact lens independent of time. This means that each
unique lens identification code is representative of one type of
contact lens only. Accordingly, a different type of contact lens
then mandatorily must have a different unique lens identification
code.
[0059] As an entire manufacturing module typically comprises quite
a number of individual manufacturing stations, some of these
manufacturing stations may be grouped together to form individual
manufacturing units, with each of these individual manufacturing
units comprising a plurality of manufacturing stations. The
manufacturing module also comprises a plurality of transfer robots
which are arranged such that between every two such subsequent
individual manufacturing units a transfer robot is arranged to
transfer the lens mold carriers from a preceding manufacturing unit
to a subsequent manufacturing unit. Thus, in one such individual
manufacturing unit a plurality of manufacturing steps/operations
can be performed, and only once these manufacturing
steps/operations have been completed the transfer robot picks the
lens mold carrier and transfers it to the subsequent manufacturing
unit. Such sub-modular construction of the manufacturing module
itself allows for adding or removing additional manufacturing
stations or units to an already existing manufacturing module, as
for a change to the manufacturing module it is then only required
to add or remove a manufacturing station/unit and possibly
add/remove a transfer robot, and to configure/program the transfer
robots in a manner such that the lens mold carriers are correctly
transferred to the desired next manufacturing station/unit.
[0060] For example, in one embodiment of the manufacturing module,
a first manufacturing unit comprises the male mold exchange
station, the female mold exchange station, and the toric axis
setting station. In this first manufacturing unit it is determined
whether or not a lot change is performed by either replacing a male
mold or a female mold, by rotating a mold, or by a combination
thereof. A second manufacturing unit comprises a dosing station for
dosing a lens forming material into the male or female molds
(typically into the female molds), a closing station for mating the
assigned pairs of lens mold carriers (and of the molds mounted to
these lens mold carriers) and a forming station for moving the
individual molds formed by the mated lens mold carriers to an
intermediate closed position. This second manufacturing unit
comprises manufacturing stations in which the molds are prepared
for the subsequent curing of a lens. A third manufacturing unit
comprises a curing station (in particular a UV-light station) for
curing the lens forming material to form lenses and a relative mold
movement station configured to perform a relative movement of the
male and female molds from the intermediate closed position to a
final closed position during curing of the lens forming material.
As is known, during curing the lens forming material with the aid
of UV-light in a comparatively short period of time (for example,
within a range of some seconds up to some twenty or some thirty
seconds) the lens forming material shrinks to a non-negligible
extent. At the same time, the relative mold movement station moves
the male and female molds relative to one another from the
intermediate closed position (into which the male and female molds
have been moved already in the forming station of the second
manufacturing unit) to a final closed position in which the cavity
formed between the male and female molds corresponds to the desired
shape of the lens. As is evident, the third manufacturing unit
comprises manufacturing stations in which a lens is formed by
curing the lens forming material. A fourth manufacturing unit
comprises a mold opening station, a rinsing station for rinsing
away any excess material, and a removal station for removing the
lenses from the molds and for transporting them away from the
manufacturing module. Obviously, this fourth manufacturing unit
comprises manufacturing stations dealing with the opening and
removal of the already cured lens from the manufacturing module. As
far as the lens manufacturing process is concerned, the lens
manufacturing process is then completed and the lens may be
transported away for further treatment (e.g. chemical treatment),
if necessary, or for inspection and subsequent packaging if no lens
treatment is necessary. Finally, a fifth manufacturing unit
comprises a mold cleaning station a mold rinsing station, and a
mold drying station. In the mold cleaning station any excess
material is removed from the molds while in the rinsing station a
final rinse of the molds is performed before the molds are dried in
the mold drying station (e.g. with the aid of drying air having a
well-defined humidity). Thereafter, the reusable molds are ready
again for being used in the next production cycle and may be either
routinely transported to the first manufacturing unit again where a
lot change on the fly may or may not be performed, or the reusable
molds may be directly transported to the second manufacturing unit
(i.e. skip the first manufacturing unit) or to the ink jet printing
unit in case no lot change is to be performed. This inkjet printing
unit is preferably arranged between the first manufacturing unit
and the second manufacturing unit.
[0061] As regards the complete production line, in addition to the
manufacturing module such production line may comprise and
extraction and treatment module in which any unwanted substances,
for example non-polymerized and/or non-crosslinked lens forming
material and/or solvents, can be extracted from the lenses. Also,
the lens can be otherwise chemically treated in the said extraction
and treatment module. For example, a coating can be applied to the
lens. Still further, the production line may comprise an inspection
module in which the extracted and/or chemically treated lenses can
be inspected. Inspection of the lenses may include an inspection of
the lenses for cosmetic defects such as inclusions, bubbles, tears,
edge defects, etc., and may also include a determination of the
optical properties (corrective power, etc.) of the lenses as well
as a determination of the center thickness of the lenses. Still
further, the production line may include a packaging module for
automatically packaging those lenses that have been identified by
the inspection module as being acceptable, so that the entire
production of the lenses--from the manufacture of the lenses to the
(primary) packaging of the lenses--can be performed completely
automatically.
[0062] Regarding the method for producing the ophthalmic lenses
using the manufacturing module, the lot change on the fly is
performed in the mold changing station by either removing at least
one mold from its mounting site on the lens mold carrier and
mounting a different mold to the said mounting site, or by changing
the rotational position of at least one of the molds. This can be
performed by removing a male mold from its mounting site and by
mounting to the said mounting site a different male mold, or by
removing from its mounting site a female mold and by mounting a
different female mold to the said mounting site, or both.
Alternatively or in addition, it is possible to change the
rotational position of the mold while the mold remains mounted to
the lens mold carrier.
[0063] Further advantageous aspects will become apparent from the
following description of embodiments of the invention with the aid
of the drawings in which:
[0064] FIG. 1 shows an embodiment of a production line according to
the invention, comprising a manufacturing module according to the
invention, an extraction and treatment module, an inspection
module, and a packaging module;
[0065] FIG. 2 shows a diagrammatic representation of an embodiment
of the production line showing the individual stations;
[0066] FIG. 3 shows an embodiment of the manufacturing module
according to the invention;
[0067] FIG. 4 shows a perspective view of a lens mold carrier
including two mold units comprising female molds which are arranged
at their mounting positions in compartments of a frame of the lens
mold carrier;
[0068] FIG. 5 shows a perspective view from above of the mold unit
shown in FIG. 4;
[0069] FIG. 6 shows a perspective view from below of the mold unit
shown in FIG. 4;
[0070] FIG. 7 shows a perspective view of a lens mold carrier
including three mold units comprising male molds which are arranged
at their mounting positions in compartments of a frame of the lens
mold carrier;
[0071] FIG. 8 shows a perspective view from above of the mold unit
shown in FIG. 7;
[0072] FIG. 9 shows a perspective view from below of the mold unit
shown in FIG. 7;
[0073] FIG. 10 shows the mold unit of FIG. 9 and the adjusting ring
lockingly connected to the adapter piece of the mold unit;
[0074] FIG. 11 shows an embodiment of the mold changing station of
the manufacturing module according to the invention; and
[0075] FIG. 12 shows the various states and actions performed
during a mold exchange.
[0076] In FIG. 1 an embodiment of a production line PL according to
the invention for the production of contact lenses, for example
soft contact lenses made of a silicone hydrogel material, is shown.
Production line PL comprises a manufacturing module MM, an
extraction and treatment module EM (in the following referred to as
"extraction module" only for the sake of simplicity), an inspection
module IM, and a packaging module PP for the primary packaging of
the contact lenses. The interfaces between the individual modules
MM, EM, IM and PP of production line PL, i.e. the locations where
the contact lenses are transferred from a preceding module to a
subsequent module, are arranged at fixed locations so that in case
changes are performed within one or more of the individual modules
MM, EM, IM and PP this does not affect the general architecture of
the production line. Such changes in the individual modules may be
caused by process changes, for example when new contact lenses are
produced using a different lens forming material. By the modular
architecture of the production line PL, the flexibility of the
production line is increase significantly, facilitating the
introduction and production of new contact lenses. In such case,
the change is performed in the respective individual module while
the general architecture of the production line including the
locations of the interfaces remains unchanged.
[0077] In the manufacturing module MM, the manufacture of the
contact lenses is performed. The manufactured contact lenses are
subsequently transferred from the manufacturing module MM to the
extraction module EM where unwanted substances, for example
non-polymerized and/or non-crosslinked lens forming material or
solvents, are extracted from the contact lenses, and where the
contact lenses may be further chemically treated. For example, a
coating may be applied to the extracted contact lenses in order to
increase their lubricity. The extracted and chemically treated
contact lenses are subsequently transferred from the extraction
module EM to the inspection module IM, where the contact lens is
inspected as to whether it is acceptable for being packaged and
distributed to customers. Once the contact lenses have been
determined by the inspection module IM as being acceptable, they
are transferred from the inspection module IM to the (primary)
packaging module PP. Contact lenses which are determined by the
inspection module IM as not being acceptable are disposed of. The
acceptable contact lenses transferred to the (primary) packaging
module PP are packaged in primary packages. The primary packages
containing the contact lenses leaving the packaging module PP are
then placed in an autoclave, and once autoclaved they are forwarded
for secondary packaging.
[0078] As is already indicated in FIG. 1 schematically by the
arrows and as is discussed in more detail further below, the
manufacturing module MM comprises a plurality of manufacturing
stations which are arranged in a closed loop, and one of these
manufacturing stations is part of the interface between the
manufacturing module MM and the extraction module EM where the
manufactured contact lenses are transferred from the manufacturing
module MM to the extraction module EM.
[0079] By way of example, in the embodiments described the molds
are arranged in mold units as will become apparent from the
description below (although in general the mold can either be
directly mounted to the lens mold carrier or in a manner other than
through the mold unit). In the manufacturing module MM, a plurality
of lens mold carriers are transported through the individual
manufacturing stations. The lens mold carriers may be embodied in
the manner shown in WO 2015/078798. One embodiment of such a lens
mold carrier 1 (comprising female mold units) is described in the
following with the aid of FIG. 4, FIG. 5 and FIG. 6.
[0080] Lens mold carrier 1 comprises a frame 10 which extends in a
plane and comprises a plurality of individual compartments 100.
Each of the compartments 100 is bounded by compartment walls 101,
102, 103, 104. In addition, in each compartment 100 there is an
angled wall portion 105 arranged in one of the corners of the
respective compartment 100.
[0081] As is shown in FIG. 4, in each of the two foremost
compartments 100 of frame 10 a female mold unit 11 is arranged.
Female mold unit 11 comprises an adapter piece 110 (see FIG. 5)
preferably made of a thermoplastic material, and a sleeve 111. A
female lens mold 112 is fixedly arranged in sleeve 111 which itself
is fixedly arranged in adapter piece 110.
[0082] Sleeve 111 has a generally cylindrical shape. At its front
end sleeve 111 extends over female lens mold 112, and this front
end of sleeve 111 comprises a chamfered portion 1110 for engaging
with a corresponding rounded front portion of the sleeve of a male
mold unit (see further below) in order to facilitate mating of the
male and female mold units. Sleeve 111 further comprises a recess
1111 into which a fixation bracket 114 engages. Fixation bracket
114 is fixedly mounted to a post 1100 projecting from the front
face of adapter piece 110 with the aid of a screw 1101 and secures
sleeve 111 against rotation.
[0083] Sleeve 111 comprises two or more circumferentially running
grooves 1112. Two fixation brackets 115 (see FIG. 6) engage into
one of the circumferentially running grooves 1112 at opposite
sides. At its back end, sleeve 111 is provided with a centrally
arranged glass disk 1113, as this is well-known in the art.
[0084] Adapter piece 110 further comprises a mold identifier 1104
comprising a transponder which is arranged in a stub projecting
from the front face of adapter piece 110. The transponder comprises
an RFID which can be read automatically and which contains
information allowing to identify the female mold 112 of the
respective female mold unit 11. Adapter piece 110 further comprises
three stubs 1105 projecting from the front face of adapter piece
110. These stubs 1105 have the same height as the stub of mold
identifier 1104.
[0085] Adapter piece 110 further comprises two pairs of resilient
latches 113 (see FIG. 5). In order to securely mount female mold
unit 11 to one of the compartments 100 of frame 10, female mold
unit 11 is pressed from above into compartment 100 until the
resilient latches 113 of adapter piece 110 snap beneath and engage
the compartment walls 103, 104 of frame 10. Once this engagement
has occurred, female mold unit 11 is floatingly arranged in the
respective compartment 100 of frame 10. Since female mold unit 11
is floatingly arranged in compartment 100, limited movement of the
adapter piece 110 is possible within compartment 100 both in a
translation plane (a plane parallel to or coincident with the plane
of the lens mold carrier, i.e. in x,y-direction) as well as in a
direction perpendicular thereto (z-direction). On the other hand,
female mold unit 11 is securely connected to frame 10 allowing for
handling and transfer of the female mold unit 11 (including female
mold 112) in the manufacturing module.
[0086] As is evident, the movement of adapter piece 110 (and thus
of female mold unit 11) within compartment 100 in z-direction is
limited by the resilient latches 113. Movement of the adapter piece
110 in the translation plane is limited by six abutment posts 116
arranged on the rear face of adapter piece 110 and projecting
therefrom, with one of the abutment posts 116 being arranged in a
specific manner to allow for mounting of adapter piece 110 to the
frame 10 in the respective compartment 100 only in one orientation
(the correct orientation). The limited movement of adapter piece
110 within compartment 100 in the translation plane may amount up
to 0.3 mm in the x-direction and up to 0.3 mm in the y-direction
(in each of the positive and negative x- or y-direction,
respectively; i.e. .+-.0.3 mm).
[0087] As can be seen from FIG. 4, frame 10 is provided with a
carrier identifier 106 comprising a transponder which is arranged
in a stub projecting from the front face of frame 10. The
transponder comprises an RFID which can be read automatically and
which contains information allowing to identify the respective lens
mold carrier 1 as well as information allowing to identify which
female mold 112 is arranged in which compartment 100 of the frame
10 of lens mold carrier 1. With the aid of the carrier identifier
106 and the mold identifier 1104 it is always possible to identify
at any time at any desired location in the manufacturing line which
mold is arranged in which compartment of which lens mold carrier.
This allows for an association of the lens mold to the respective
contact lenses produced with that lens mold which may be
advantageous, for example, for quality monitoring and tracking
purposes.
[0088] For further details of lens mold carrier 1 it is referred to
the description of the afore-mentioned WO 2015/078798.
[0089] A further embodiment of such lens mold carrier, also
described in detail in WO 2015/078798 is described in the following
with the aid of FIG. 7, FIG. 8, FIG. 9 and FIG. 10 (an embodiment
comprising male mold units). Many details of this further
embodiment of the lens mold carrier 2 and of its components are
similar to those of the first embodiment of the lens mold carrier
1, so that not each and every detail is explained again. As a
general rule, the leading numeral "1" of the reference signs used
for the embodiment of the lens mold carrier described above is
replaced with the leading numeral "2" in the further embodiment of
the lens mold carrier described below.
[0090] Accordingly, lens mold carrier 2 comprises a frame 20 which
extends in a plane and comprises a plurality of individual
compartments 200. Each of the compartments 200 is bounded by
compartment walls 201, 202, 203, 204. In addition, in each
compartment 200 there is an angled wall portion 205 arranged in one
of the corners of the respective compartment 200.
[0091] As is shown in FIG. 7, in each of the three foremost
compartments 200 of frame 20 a male mold unit 21 is arranged. Male
mold unit 21 comprises an adapter piece 210, preferably made of a
thermoplastic material, and a sleeve 211. A male lens mold 212 is
fixedly arranged in sleeve 211. Sleeve 211 is arranged in a central
opening of adapter piece 210 and is lockingly connected to the
adapter piece 210 at a fixed angular position, but can be rotated
relative to adapter piece 210 to get lockingly connected to the
adapter piece 210 at another fixed angular position, as will be
explained in more detail below.
[0092] Sleeve 211 has a generally cylindrical shape (see FIG. 8).
At its front end sleeve 211 extends over male lens mold 212, and
this front end of sleeve 211 of male mold unit 21 comprises a
rounded portion 2110 for engaging with the chamfered portion 1110
of sleeve 111 of the female mold unit 11 (see FIG. 5) in order to
facilitate mating of the male and female mold units. Sleeve 211
comprises two circumferentially running grooves 2112. A toothed
adjusting ring 214 (see FIG. 8, FIG. 10) comprising two assembled
ring pieces is arranged in one of these grooves 2112 (see FIG. 9)
as well as two fixation brackets 215 which engage into the same
groove 2112 at opposite sides. Adjusting ring 214 is firmly
attached to sleeve 211 so that it can be rotated only together with
sleeve 211 relative to adapter piece 210 in a plane parallel to the
plane of the lens mold carrier 2 (u-v plane). However, rotation of
adjusting ring 214 is only possible between fixed angular
positions, at which the toothed adjusting ring 214 lockingly
engages with two fixedly arranged locking teeth 2110 which are
provided on locking elements that form part of the adapter piece
210 (see FIG. 10), these two locking teeth 2110 being arranged at
opposite sides. Thus, adjusting ring 214 is lockingly connected to
the adapter piece 210 at fixed angular positions. This is
advantageous in the production of toric contact lenses since it
allows, with the aid of a handling system, to automatically change
the angular position of the axes of (toric) male mold 212 by
rotating adjusting ring 214 (and together with it male mold unit 21
including male mold 212) by one or more fixed angular increments
relative to adapter piece 210, and to then have it lockingly
connected with adapter piece 210 again at a different angular
position, so that a toric contact lens with a different arrangement
of the axes can be produced. At its back end, sleeve 211 is
provided with a centrally arranged glass disk 2113 allowing
UV-light to pass through to the mold for curing the lens forming
material, as this is well-known in the art.
[0093] Adapter piece 210 further comprises a mold identifier 2104
comprising a transponder which is arranged in a stub projecting
from the rear face of adapter piece 210. The transponder comprises
an RFID which can be read automatically and which contains
information allowing to identify the male mold 212 of the
respective male mold unit 21.
[0094] Adapter piece 210 further comprises two pairs of resilient
latches 213. In order to securely mount male mold unit 21 to the
frame 20 in one of the compartments 200, male mold unit 21 is
pressed from above into compartment 200 until the resilient latches
213 of adapter piece 210 snap beneath and engage the compartment
walls 203, 204 of frame 20. Once this engagement has occurred, male
mold unit 21 is floatingly arranged in the respective compartment
200. Since male mold unit 21 is floatingly arranged in compartment
200, limited movement of the adapter piece 210 is possible within
compartment 200 both in a translation plane (which is a plane
parallel to or coincident with the u-v plane) as well as in a
direction perpendicular thereto (w-direction). On the other hand,
male mold unit 21 is securely connected to frame 20 allowing for
handling and transfer of the male mold unit 21 (including male mold
212) in the manufacturing module.
[0095] As is evident, the movement of adapter piece 210 (and thus
of male mold unit 21) within compartment 200 in w-direction is
limited by the resilient latches 213. Movement of the adapter piece
210 in the translation plane is limited by six abutment posts 2106
arranged on the rear face of adapter piece 210 and projecting
therefrom, with one of the abutment posts 2106--that one in the
lower left corner in FIG. 10--being arranged in a specific manner
to allow for mounting of adapter piece 210 to the frame 20 in the
respective compartment 200 only in one orientation (the correct
orientation). The limited movement of adapter piece 210 within
compartment 200 in the translation plane may amount up to 0.3 mm in
the u-direction and up to 0.3 mm in the v-direction (in each of the
positive and negative u- or v-direction, respectively; i.e. .+-.0.3
mm).
[0096] As can be seen from FIG. 7, frame 20 is provided with a
carrier identifier 206 comprising a transponder which is arranged
in a stub projecting from the front face of frame 20. The
transponder comprises an RFID which can be read automatically and
which contains information allowing to identify the respective lens
mold carrier 2 as well as information allowing to identify which
male mold 212 is arranged in which compartment 200 of the frame 20
of lens mold carrier 2. With the aid of the carrier identifier 206
and the mold identifier 2104 it is always possible to identify at
any time at any desired location in the manufacturing line which
mold is arranged in which compartment of which lens mold carrier.
This allows for an association of the lens mold to the respective
contact lenses produced with that lens mold which may be
advantageous, for example, for quality monitoring and tracking
purposes.
[0097] For further details of lens mold carrier 2 it is referred to
the description of the afore-mentioned WO 2015/078798. The
embodiment of lens mold carrier 1 and the embodiment of lens mold
carrier 2 described above can be used in the manufacturing module
of the production line PL according to the invention, an embodiment
of which is already described with respect to FIG. 1.
[0098] In FIG. 2 a diagrammatic representation of an embodiment of
the production line PL is shown showing the individual stations of
the manufacturing module MM, the extraction module EM, the
inspection module IM, and the (primary) packaging module PP.
[0099] In the manufacturing module MM, individual manufacturing
stations are grouped together to form a plurality of individual
manufacturing units, as is discussed below in more detail. A first
manufacturing unit 30 labelled "CTI" comprises a male mold exchange
station 300, a female mold exchange station 301 and a toric axis
setting station 302.
[0100] In the male mold exchange station 300, in order to effect a
lot change on the fly, for example at mounting site number one
(corresponding to the foremost compartment 200 of lens mold carrier
2), it is possible to remove a male mold unit 21 from the foremost
compartment 200 of lens mold carrier 2 and to mount a different
male mold unit into the said foremost compartment 200 from which
the male mold unit 21 has been removed. Alternatively, in the
female mold exchange station 301, in order to effect a lot change
on the fly, for example at mounting site number one (corresponding
to the foremost compartment 100 of lens mold carrier 1), it is
possible to remove a female mold unit 11 from the foremost
compartment 100 of lens mold carrier 1 and to mount a different
female mold unit to the said compartment 100. Of course, it is also
possible to remove both the male mold unit 21 and the female mold
unit 11 from the respective foremost compartment of the respective
lens mold carrier to effect a lot change on the fly at mounting
position number one. Further alternatively, in order to effect a
lot change on the fly by producing a different toric contact lens,
in the toric axis setting station 302 it is possible to rotate
adjusting ring 214 (and together with it the male mold 212) by one
or more fixed angular increments relative to adapter piece 210, and
to then have it lockingly connected with adapter piece 210 again at
a different angular position, so that a toric contact lens with a
different arrangement of the axes can be produced. The first
manufacturing unit labelled "CTI" will be explained in more detail
further below.
[0101] Lens mold carrier 1 and lens mold carrier 2 are then
transferred from manufacturing unit 30 ("CTI") to the next
manufacturing station.
[0102] The next manufacturing station in the embodiment of the
manufacturing module MM of the production line PL is an inkjet
printing station 310. In the inkjet printing station, a unique lens
identification code, for example a unique code of ink dots or any
other suitable type of code is printed onto a mold, e.g. onto the
female mold. The code is representative of the characteristics of
the contact lens to be produced. This unique lens identification
code is applied in each subsequent production cycle to the mold
surface.
[0103] The ink dots printed on the mold are later transferred to
the material forming the contact lens, for example they are
embedded into the material forming the contact lens. The
information contained in the unique lens identification code may
comprise the following information (without being exhaustive): Lens
material, base curve radius, optical corrective power, etc.
[0104] It is also possible that some or all of the coded
information is provided on the contact lens through embossing, that
is to say, one or both of the molds may have projections in a
non-optical peripheral portion of the mold or molds which may
produce corresponding embossments in the contact lens in a
non-optical peripheral portion of the contact lens. Also
combinations of embossing and inkjet printing are possible.
[0105] It is to be noted that the inkjet printing station 310 is
optional only as the code can be provided in a different manner.
Also, in general it is not mandatory that a code be provided on the
contact lens, as the system control (not shown) of the production
line PL always knows what type of mold is on each mounting position
of each lens mold carrier on the production line PL.
[0106] Lens mold carrier 1 and lens mold carrier 2 are then
transferred from to a second manufacturing unit 32.
[0107] Second manufacturing unit 32 labelled "DCF" comprises a
dosing station 320, a closing station 321 and a forming station. In
the dosing station 320 a predetermined quantity of lens forming
material is dispensed (dosed) into the female molds 112 of the
female mold units 11 of lens mold carrier 1. Thereafter, in the
closing station 321 assigned pairs of lens mold carriers 1 and 2
are mated, so that upon mating lens mold carrier 1 and lens mold
carrier 2, the female molds 112 of lens mold carrier 1 and the
respective male molds 212 of lens mold carrier 2 are mated to form
mold cavities. All lens mold carriers 1 comprise female male mold
units 11 with female molds 112 while the respective assigned lens
mold carriers 2 comprise male mold units 21 with male molds 212. In
the forming station 322, the respective male molds 212 and female
molds 112 are moved into an intermediate closed position, in which
the molds are not yet in their final closed position.
[0108] In the following, an example is described how lens mold
carrier 1 and lens mold carrier 2 may work together in the
manufacturing unit 32. As has been described above, the
compartments 100 in frame 10 of lens mold carrier 1 and the
compartments 200 in frame 20 of corresponding lens mold carrier 2
are very precisely arranged, and adapter piece 110 of female lens
mold unit 11 is floatingly arranged in compartment 100 while
adapter piece 210 of male lens mold unit 21 is floatingly arranged
in compartment 200. Due to the precise arrangement of the
compartments 100 and 200 of the frames 10 and 20 the sleeves 111
and 211 are already coarsely aligned as the lens mold carrier 2 is
moved towards lens mold carrier 1. During mating, the precise
alignment of each pair of associated male mold units 21 and female
mold units 11 is then performed automatically: As the rounded
portion 2110 of the front end of sleeve 211 comes into contact with
the chamfered portion 1110 of the front end of sleeve 111 during
mating the lens mold carrier 1 carrying the female mold units 21
and the lens mold carrier 2, either one adapter piece or both
adapter pieces of male mold unit 21 and female mold unit 11 move
within their respective compartments until the sleeves are
precisely aligned whereby the molds are precisely aligned with the
aid of the cylindrical outer surface of sleeve 111 that extends
over the female mold 112 and the inner surface of sleeve 211 that
extends over the male mold 212. This happens with each pair of
associated male mold units 21 and female mold units 11 and is
possible due to the floating arrangement of the adapter pieces
within the respective compartments. All male mold units 11 and
female mold units 21 (including the male molds 212 and female molds
112) are then precisely aligned. The lens mold carriers are then
further moved towards each other until the molds are closed, with
the individual molds being perfectly aligned. Thereafter, the
sleeves may be moved a small distance apart again so that the molds
are in the intermediate closed position which is not the final
closed position.
[0109] The mated lens mold carriers 1, 2 are then transferred to a
third manufacturing unit 33.
[0110] Third manufacturing unit 33 comprises a curing station and a
relative mold movement station 330, in which the lens forming
material is cured, for example with the aid of UV-light. As is
well-known, during UV-light curing the lens forming material is
polymerized and/or crosslinked to form the contact lens, however,
during curing shrinkage of the lens forming material is known to
occur. As both the female molds 112 and the male molds 212 are
reusable molds typically made of glass (e.g. quartz glass or any
other suitable glass known in the art) the molds themselves cannot
deform to compensate for the shrinkage. Therefore, a relative mold
movement is performed such that the male and female molds are moved
relative to each other from the afore-mentioned intermediate closed
position to the final closed position in accordance with a
predetermined movement profile which takes the shrinkage process
into account, so that the shape of the contact lens is determined
by the shape of the male and female molds in the final closed
position. Such relative mold movement of the male and female molds
is known in the art and can be performed in different ways, as is
described, for example, in WO 2011/045397.
[0111] The mated lens mold carriers 1, 2 containing the formed
contact lenses are then transferred to a fourth manufacturing unit
34.
[0112] Fourth manufacturing unit 34 labelled "ORW" comprises an
opening station 340 in which the mated lens mold carriers 1, 2 are
separated thus opening the molds, a rinsing station 341 for rinsing
away excess lens forming material, and a lens removal station 342
labelled "Waterflow" for removal of the contact lens from the mold
and for transferring the contact lens from the manufacturing module
MM to the extraction module EM. The lens removal station has been
labelled "Waterflow" as removal of the contact lens from the mold
and transfer of the contact lens from the manufacturing module MM
to the extraction module EM can be performed with the aid of a flow
of fluid, for example water, as this is known in the art and
described, for example, in WO 2008/116856.
[0113] Once the contact lenses are transferred from the
manufacturing module MM to the extraction module EM, the lens mold
carrier 1 with the female mold units 11 comprising the female molds
112 and the lens mold carrier 2 with the male mold units 21
comprising the male molds 212 are transferred to a fifth
manufacturing unit 35.
[0114] Fifth manufacturing unit 35 labelled "MCD" comprises a mold
cleaning station 350 for cleaning the molds, a rinsing station 351
for a final rinse of the molds, and a subsequent drying station 352
for drying the molds, for example with the aid of air having a
well-defined humidity of the drying air. The carrier 1 with the
female mold units 11 and the cleaned, rinsed and dried female molds
112 as well as the carrier 2 with the male mold units 21 and the
cleaned rinsed and dried molds are then returned to the first
manufacturing station labelled "CTI", thus closing the loop and
starting the described lens manufacturing process for the next
production cycle.
[0115] The material flow of the contact lens in the manufacturing
module MM is indicated in FIG. 2 by continuous lines whereas the
flow of the lens mold carriers or the molds, respectively, in the
manufacturing module MM is indicated by dashed lines.
[0116] The manufacturing module MM described above in connection
with the diagrammatic representation in FIG. 2 is shown in FIG. 3
again in a more structure-related schematic representation showing
the arrangement of the individual manufacturing units 30, 32, 33,
34 and 35, as well as the (optional) inkjet printing station 310.
As can be seen, transfer robots 36 are arranged between the first
manufacturing unit 30 labelled "CTI" and inkjet printing station
310, between inkjet printing station and second manufacturing unit
32 labelled "DCF", between second manufacturing unit 32 labelled
"DCF" and third manufacturing unit 33 labelled "RMM/UVL", between
the third manufacturing unit 33 labelled "RMM/UVL" and fourth
manufacturing unit 34 labelled "ORW", between fourth manufacturing
unit 34 labelled "ORW" and fifth manufacturing unit labelled "MCD",
and between fifth manufacturing unit 35 labelled "MCD" and first
manufacturing unit labelled "CTI". Transfer robots 36 transfer lens
mold carriers 1, 2 from one manufacturing unit to the next
manufacturing unit. This configuration of the manufacturing module
MM is advantageous as it is easily possible to make changes to the
manufacturing module MM. For example, additional manufacturing
stations or manufacturing units can be added to or manufacturing
stations or manufacturing units can be removed from the
manufacturing module MM, or the existing manufacturing stations can
be rearranged at different locations within the manufacturing
module MM. In each such case, it is only necessary to make the
robots transfer the lens mold carriers to the location of the
respective new location of the next manufacturing unit or
manufacturing station. In the case of adding an additional
manufacturing station or manufacturing unit to the manufacturing
module MM, one or more additional robots are needed.
[0117] Turning back to FIG. 2, transfer of the contact lenses from
the manufacturing module MM to the extraction module EM is
performed in the removal station 342 labelled "Waterflow", as has
been described above. The contact lenses are transferred through
plastic tubes into containers waiting in a receiving station 400 of
the extraction module EM for the contact lenses to arrive. As the
lens mold carriers described above comprise fourteen molds each,
fourteen contact lenses are produced at the same time. Accordingly,
fourteen contact lenses are transferred from the manufacturing
module MM to the extraction module EM at the same time.
Consequently, fourteen containers are respectively provided in a
receiving station for receiving the fourteen contact lenses
transferred from the removal station 342 (labelled "Waterflow") of
the manufacturing module MM. Containers suitable to transport the
contact lenses through the different stations of the extraction
module EM are known for example, from WO 2011/045384.
[0118] The manufacturing process performed in the manufacturing
module MM typically is a cyclic process performed with a
predetermined cycle time for all process steps. This holds for the
extraction and treatment process performed in the extraction module
EM, too. However, as the cycle time of the manufacturing process
performed in the manufacturing module MM and the cycle time of the
extraction and treatment process performed in the extraction module
EM may be different, in order to account for such difference in
cycle times an apparatus for transferring the contact lenses
between the manufacturing module MM and the extraction module EM
can be used as is disclosed in WO 2012/080468.
[0119] In the extraction module, the contact lenses are received in
the afore-mentioned containers in a receiving station 400 labelled
"IN (Water)" and are subsequently transported through different
dipping baths. For that purpose, an apparatus as disclosed in WO
2011/045380 can be used, for example. The contact lenses contained
in the containers are first transported from the receiving station
400 (labelled "IN (Water)") to an extraction station 401 (which may
comprise one or more extraction baths) where unwanted substances,
for example non-polymerized and/or non-crosslinked lens forming
material or solvents, are extracted from the contact lenses.
Thereafter, the contact lenses contained in the containers are
again transported to a neutralization station 402 (labelled
"Water") which may comprise one or more water baths. Subsequently,
the contact lenses contained in the containers are transported to a
coating station 403 (which may comprise one or more coating baths)
for applying a coating to the contact lenses. Thereafter, the
contact lenses contained in the containers are again transported to
a neutralization station 404 (labelled "Water" again) before they
are transported to a transfer station 405 (labelled "OUT (Water)")
from where the contact lenses contained in the container are
transferred from the extraction module EM to an inspection module
IM for inspection as this is represented by the continuous line in
FIG. 3 starting at the base of transfer station 405 and ending at
the first inspection station of the inspection module IM. The
containers of the extraction module EM are then returned to the
receiving station 400 (labelled "IN (Water)") as is indicated by
the dashed lines in FIG. 3.
[0120] Removal of the contact lenses from the containers at the
transfer station 405 of extraction module EM and transfer of the
contact lenses into inspection cuvettes waiting in the inspection
module IM can be performed using a suitable gripper. Inspection
cuvettes suitable for being used in the inspection module IM are
known, for example, from WO 03/016855, while a gripper suitable for
the transfer of the contact lenses from the containers of
extraction module EM into the inspection cuvettes waiting in
inspection module IM is disclosed in WO 2012/066060, for
example.
[0121] In the inspection module IM, the contact lenses contained in
the inspection cuvettes are first inspected in a first inspection
station 500 of the inspection module IM as to whether or not the
contact lenses are inverted. By way of example, such type of
inspection can be performed in the manner described in WO
2015/036432. In case the result of this inspection is that a
contact lens is inverted, the contact lens can be re-inverted in a
second inspection station 501 of the inspection module in order to
thereafter have the contact lens arranged in the inspection cuvette
in the correct inversion state (i.e. the contact lens is
non-inverted). Re-inversion of the contact lens can be performed in
the manner described in WO 2009/103732, for example. Once in the
proper inversion state, the contact lens is inspected for cosmetic
defects such as bubbles, inclusions, edge defects (e.g. tears),
etc., in a third inspection station 502 of the inspection module
IM. This cosmetic inspection can be performed in the manner
described in WO 2007/060173, for example. In a subsequent fourth
inspection station 503 (labelled "Diopter measurement"), the
contact lens is inspected to determine its optical parameters such
as the optical power. This can be performed in the manner described
in WO 2014/049053, for example. Finally, in a fifth inspection
station 504 (labelled "CT measurement") the contact lens is
inspected to determine the central thickness of the contact lens,
and this can be performed, for example, in the manner described in
WO 2014/049050. The sequence of the inspection stations in
inspection module IM is not limited to the sequence shown in FIG.
2, at least the three last inspection stations can be arranged in a
different sequence (however, inspection of the contact lens should
occur with the contact lens being in the proper inversion
state).
[0122] In case a contact lens has failed to pass one or more of the
inspections performed in the third inspection station 502
("Cosmetic inspection"), the fourth inspection station 503
("Diopter measurement") or the fifth inspection station 504 ("CT
measurement"), such contact lens is sorted out and discarded.
Contact lenses that have passed all of the afore-mentioned
inspection steps are transferred into a primary package waiting in
a lens placement station of a (primary) packaging module PP, as
this is indicated by the continuous line. A primary package
suitable for this purpose and comprising a packaging shell and a
foil sealed to the top surface of the packaging shell is described,
for example, in U.S. Pat. No. 5,609,246. The inspection cuvettes
are cleaned and returned to the first inspection station 500 where
contact lenses coming from the extraction module EM are transferred
into the inspection cuvettes in the inspection module IM again, as
this is indicated by the dashed lines.
[0123] In the (primary) packaging module PP, in a first packaging
station 600 (labelled "Shell feeder") packaging shells are
supplied. In a second, optional packaging station 601 (labelled
"Print on shell") various information may be printed on the shell
(such as, for example, date of production, contact lens data,
etc.). Next, in a third packaging station 602 the packaging shells
are placed on a carrier on which the packaging shells are further
transported through the packaging module PP. For example, five
packaging shells are arranged on the same carrier. In a subsequent
fourth packaging station 603, the contact lenses that have
successfully passed all inspections in the inspection module IM are
placed into the packaging shells arranged on the carrier, until
each of the packaging shells contains a contact lens (in each of
the individual packaging shells on the same carrier the same type
of contact lens is contained). The transfer of a contact lens out
of the inspection cuvettes used in the inspection module and into a
packaging shell arranged on the carrier can be performed, with the
aid of a gripper. A gripper suitable for this transfer is described
in WO 2011/026868, for example.
[0124] In the fifth packaging station 604 (labelled "lens presence
check") it is determined whether in each of the packaging shells a
contact lens is contained in order to prevent a packaging shell
from being sealed with a foil with no contact lens being contained
in the packaging shell for any reason (for example, a contact lens
has not been properly placed in the packaging shell, or a gripper
has indicated that a contact lens has adhered to the gripper and
has been placed into the shell although actually no contact lens
has adhered to the gripper). The lens presence check can be
performed, for example, with the aid of a camera suitable to read
the ink code of the contact lens which does not only indicate the
presence of the contact lens in the packaging shell but can also be
used to check (by identification of the ink code) whether the
correct contact lens is contained in the packaging shell.
[0125] The carrier is then moved to a sixth packaging station 605
(labelled "Configuration station") which is an optional station.
The configuration station is a kind of an intermediate buffer in
which contact lenses can be temporarily stored in packaging shells
(without a foil being sealed thereto), however, only for a
predetermined time so as to prevent the contact lenses in the
packaging shells from drying. If it has been detected in the fifth
packaging station 604 ("lens presence check") that there is one or
more shells arranged on the carrier in which no contact lens is
contained, a check is performed whether one or more shells
containing a contact lens of the same type are present in the
configuration station. In case such packaging shell is present in
the configuration station, the shell on the carrier that does not
contain a contact lens is removed from the carrier and is the
corresponding shell containing the same type of contact lens is
taken from the configuration station and is placed on the carrier
instead.
[0126] As the configuration station is optional only, in case there
is no configuration station and it is detected during the lens
presence check performed in the fifth packaging station 604 that a
contact lens is missing in one or more of the packaging shells on a
carrier, then the whole arrangement of shells on that carrier is
discarded (since the shells arranged on the same carrier are
typically sealed together to form a strip as will be described
below, and this would mean that in one or more of the shells of a
strip no contact lens is contained, which is not acceptable).
[0127] In a seventh packaging station 606 (labelled "Dose saline")
a predetermined amount of packaging liquid is dispensed (dosed)
into each of the packaging shells.
[0128] It is of course also possible to arrange the fifth packaging
station 604 ("lens presence check") downstream of the seventh
packaging station 606 ("Dose saline"), in particular as it may turn
out that the lens identification code is difficult to read as the
contact lens may not be completely unfolded without a sufficient
amount of saline being present in the packaging shell.
[0129] In a subsequent eighth packaging station 607 (labelled
"Place foil on shell") a foil, for example a laminated aluminum
foil comprising a thermoplastic layer, is placed on the shell.
Alternatively, as is well-known, a foil strip extending over a
plurality of packaging shells adjacently arranged on a carrier is
sealed to each of the adjacently arranged packaging shells to form
a strip of contact lens packages in which the individual packages
of the strip are connected to one another by the foil strip. The
foil strip connecting the individual packages to the strip of
contact lens packages can be scored or perforated at the connection
between adjacent packages of the strip so as to allow for
separation of an individual contact lens package from the
strip.
[0130] Thereafter, in a ninth packaging station 608 (labelled
"Sealing") the foil or the foil strip, respectively, is sealed to
the packaging shell (or to the packages, respectively) at the top
surface of the packaging shell. In a subsequent tenth packaging
station 609 (labelled "Laser printing on foil") information (e.g.
base curve radius, optical power, etc.) related to the contact lens
contained in the package is printed on the foil, for example by
using laser printing.
[0131] Dosing packaging liquid into the shell, lens presence check,
placing and sealing of a foil to the shell, and laser printing are
all conventional techniques and, therefore, they are not discussed
in detail.
[0132] In an (optional) eleventh packaging step 610 (labelled "Pull
samples") some sealed packages or strips of the sealed packages may
be taken from the production line from time to time and may be
inspected offline to make sure that the production line works well
and to ensure quality of the packaged contact lenses. Finally, in a
twelfth packaging step 611 (labelled "Blister into magazines") the
sealed and printed contact lens packages or strips of contact lens
packages are removed from the carriers and are placed into
magazines for autoclaving. The carriers are then returned for the
next packaging shells being placed on them.
[0133] Autoclaving of the contact lens packages or strips of
contact lens packages is then performed in an autoclave 700, and
once autoclaving is performed the autoclaved contact lens packages
are further placed in a secondary packaging line 800 (labelled
"Secondary packaging") into secondary packages, for example
cartons, which form the final product 900 for subsequent
shipping.
[0134] As has been mentioned above already, with the modular
production line PL according to the invention, and in particular
with the manufacturing module MM according to the invention, it is
possible to perform a lot change on the fly, that is to say it is
possible to exchange (replace) at least one of the molds on the
lens mold carriers without the need to interrupt production and
without the need to clear the production line by removing all lens
mold carriers from the production line and place new lens mold
carriers on the production line.
[0135] In the manufacturing module MM according to the invention,
the lot change on the fly can be performed by the first
manufacturing unit 30 (labelled "CTI") in FIG. 2 and FIG. 3. One
example of such manufacturing unit 30 is shown in more detail in
FIG. 11. Insertion and removal of the lens mold carriers 1, 2 into
and from the manufacturing unit 30 are indicated by respective
arrows. Manufacturing unit 30 comprises a rotary table 39 which can
be rotated clockwise, for example, as is indicated in FIG. 11 by
the curved arrows in the center of table 39. At station 301, female
molds can be exchanged by removing female mold units 11 from their
compartment 100 of lens mold carrier 1 and by mounting a different
female mold unit 11a to the said compartment 100 of lens mold
carrier 1 from which female mold unit 11 has been removed. For
example, in FIG. 11 it is shown that female mold unit 11 arranged
at position number two (hatched in FIG. 11) of lens mold carrier 1
is exchanged and replaced with a different mold unit 11a with the
aid of a respective exchange tool 37, as will be described in more
detail below with respect to FIG. 12. Once the exchange of female
mold unit 11 is completed, rotary table 39 is rotated clockwise by
ninety degrees so that at station 300 a male mold exchange can be
performed. Exchange of a male mold unit 21 (and replacement with a
different male mold unit 21a) can be performed similar to an
exchange of a female mold unit in the same manner using a similar
mold exchange tool 37. By way of example, exchange of male mold
unit 21 may be performed at position number two of lens mold
carrier 2. The male and female mold exchanges (by exchanging the
mold units) are indicated by double-headed arrows in FIG. 11. Once
the exchange of the male mold unit 21 is completed, rotary table 39
is again rotated clockwise by ninety degrees, so that at station
302 a toric axis setting/change can be performed. This can be
performed, for example, with a suitable rotation tool (not shown)
which may engage the flat surfaces of sleeve 211 at the back end of
male mold unit 21 (see FIG. 10) and rotate sleeve 211 either
clockwise or counterclockwise by one or more teeth of the toothed
adjusting ring 214, as this is already described further above.
Once the toric axis setting/change is completed, table 39 is
rotated again clockwise by ninety degrees so that in a further
station 303 the individual RFIDS of the molds can be read and
stored so that it is known what type of mold is arranged at what
compartment 100, 200 of the lens mold carriers 1, 2. Lens mold
carriers 1, 2 are then removed with the aid of a robot 36 and are
transported to the next station, for example the inkjet printing
station 310 as described above with respect to FIG. 2 and FIG. 3.
It goes without saying, that either a male mold exchange, or a
female mold exchange, or a toric axis change/setting can be
performed in order to perform a lot change on the fly, or
combinations thereof. If no lot change on the fly is to be
performed, none of these exchanges/changes/settings is
performed.
[0136] FIG. 12 shows the individual states during a female mold
exchange performed with the aid of an exchange tool 37. In the
upper left box of FIG. 12, exchange tool 37 is shown in its initial
position. In this initial position, exchange tool 37 is arranged
above female mold unit 11 arranged in the compartment 100 at
position number two of lens mold carrier 1. Exchange tool 37
comprises two gripper arms 370, 371. Gripper arm 370 is empty and
ready for gripping female mold unit 11 to be removed from
compartment 100 of lens mold carrier 1 while gripper arm 371 holds
a new female mold unit 11a to be inserted into the said compartment
100 of lens mold carrier 1 after female mold unit 11 has been
removed. As can be seen further in FIG. 12, there is a snap fit
release tool 38 having two arms 380, 381 that can be moved towards
and away from each other. As is indicated by the arrow in the upper
left box of FIG. 12, exchange tool 37 is then lowered from the
initial position towards female mold unit 11 to be exchanged.
[0137] In the upper central box of FIG. 12, it is shown that
gripper arm 370 of exchange tool 37 has been lowered until it
engages female mold unit 11. Arms 380, 381 of snap fit release tool
38 are moved towards each other (see arrows) to flex resilient
latches 113 (see FIG. 5) of female mold unit 11 inwardly. As can be
seen in the upper right box of FIG. 12, gripper arm 370 of exchange
tool 37 is then raised again (see arrow) with female mold unit
being gripped by gripper arm 370, thus removing female mold unit 11
from compartment 100 of lens mold carrier 1. As can be seen in the
lower left box of FIG. 12, exchange tool 37 is then rotated
clockwise or counterclockwise by 180.degree. thus arranging gripper
arm 371 holding new female mold unit 11a to be inserted above the
compartment 100 of lens mold carrier 1 from which female mold unit
11 has been removed. Gripper arm 371 of exchange tool 37 is then
lowered (see arrow in lower left box of FIG. 12) until new female
mold unit 11a is placed into compartment 100 of lens mold carrier
1. At that time, arms 380, 381 of snap fit release tool 38 are
still in the position in which they have been moved towards each
other to allow for easy insertion of the resilient latches of new
female mold unit 11a into compartment 100 of lens mold carrier 1.
Once new female mold unit 11a has been inserted into compartment
100 of lens mold carrier 1 as shown in the central lower box of
FIG. 12, arms 380, 381 of snap fit release tool 38 are moved away
from each other again (see arrows in central lower box of FIG. 12).
New female mold unit 11a is now mounted to the frame of lens mold
carrier 1 at compartment 100, and the exchange process.
[0138] While embodiments of the manufacturing unit according to the
invention and of the production line according to the invention
have been described above with the aid of the drawings, it is
evident that many modifications and changes are possible without
departing from the teaching underlying the invention. Therefore,
the invention is not limited to the embodiments shown and
described, but rather the scope of protection is defined by the
appended claims.
* * * * *