Abstract:
A method and apparatus for connecting a metal lid to a metal body of a container to seal any product held by the container. The container is formed from a generally cylindrical metal body having an upper edge and a metal lid having a peripheral edge. The metal lid is held in position on the metal body so that the upper edge portion of the metal body and the peripheral edge of the metal lid form a contiguous junction. A beam of laser energy is directed toward the contiguous junction for sufficient time to hermetically seal the lid to the body. A single roll-formed lip provides a smooth finish to the combined body and lid. The lid includes a circumferentially continuous recess surrounding a central planar portion of the lid. The recess is located adjacent the peripheral edge while the peripheral edge is situated at or below the plane defined by the central planar portion, thereby reducing the material required to form a sealed container of any given volume.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates generally to metal containers and more particularly to methods and apparatus for forming metal containers.  
         BACKGROUND OF THE INVENTION  
         [0002]    Metal containers, such as those used to contain beverages, including soda pop, beer and the like, are well known. Such containers, commonly known as cans, comprise a generally cylindrical body open at one end with a lid enclosing the open end and mechanically connected to the body. As shown in FIG. 1, conventional beverage cans  1  utilize a roll formed connection  2  between the lid  3  and the body  4  of the can. The roll form interconnection  2  between the lid  3  and body actually comprises two rolls of adjacent edges of the lid and body. A first edge  5  of the lid  3  is rolled outwardly over an upper edge portion  6  of the body  4  and thereafter the edges  5  and  6  are rolled together outwardly over the body  4  to provide five layers of material in the roll formed region as shown. The double roll form  2  requires the can to be passed through a plurality of workstations on chassis and around carousels where the can is “rolled” by a plurality roll form tools that increasingly effect the various stages of the roll form between the lid  3  and can body  4 . This complex tooling is costly to install and maintain, thus contributing to the cost of manufacture of the cans.  
           [0003]    While generally effective at connecting the lid to the body, the double roll form connection of conventional beverage containers utilizes a significant amount of material in the area of the roll formed connection, and also requires specific structures on the lid and body. The specific structures required include a recess in the lid providing a significant sidewall and engagement area for a mandrel, which engages and rotates the lid and the can body.  
           [0004]    Further, while such mechanical roll forming is generally effective at connecting the lid  3  to the body  4 , it does not provide a hermetic seal for the container. To provide a hermetic seal, an annular vinyl seal (labeled “A” in FIG. 1) must be disposed between the lid and the body in the area of the roll formed connection and prior to connecting the lid to the body. The vinyl seal increases the cost and difficulty of assembling a can and also requires additional machinery to locate and assemble the vinyl seal into the can.  
           [0005]    Containers such as beverage cans and the like are processed in high volume at high speeds. The cans are filled with a beverage prior to connecting the lid to the body. The connection between the lid and body is mechanically provided at successive roll forming stations. The quality of individual roll form connections is not monitored, but rather, samples are tested downstream of all the roll-forming stations. When a defect is detected in the sample, there is no way to determine if the defect is an isolated incident or if the entire lot from which the sample was picked is defective. Accordingly, the entire lot and any additional inspected cans and/or lots of cans are rejected. Thus with each detected defect, a large volume of beverage product is wasted, and the output of filled cans is reduced thereby decreasing the efficiency and increasing the cost of the container forming and filling process.  
           [0006]    There is therefore a need for container forming and sealing processes and equipment that can produce filled cans at a rate at least comparable to current manufacturing practices with increased reliability, use of less materials, and with tools and equipment that are less costly to install and maintain.  
         SUMMARY OF THE INVENTION  
         [0007]    A metal container in accordance with the present invention has a lid laser welded to an open end of a body of the container to join the lid to the body and to provide a hermetic seal between them. Desirably, the lid is placed directly on the container body, welded thereto and thereafter a single roll form occurs to reduce or eliminate any sharp edges and provide a smooth rim of the container. Far less material is required in the area of the lid and body connection of the present invention compared to conventional beverage containers having a double roll formed connection between the lid and the body. Further, laser welding the lid to the body provides a hermetic seal without the presence of any vinyl seal between the lid and body. Accordingly, the cost of the vinyl seal and the equipment needed to assemble the seal between the lid and body is eliminated.  
           [0008]    Still further, an apparatus in accordance with the present invention to laser weld the lid to the body can be flexibly designed and can be adapted for use with conventional chassis and carousels that transport the containers between various roll forming workstations, or can process the cans in-line as they are carried downstream from a filling station by one or more conveyors. Therefore, the invention contemplates, without limitation, a container having an improved connection between a body and lid, and methods and apparatus for forming the improved container.  
           [0009]    Objects, features and advantages of this invention include: providing a container having a body portion which can be formed of less material compared to conventional containers, a lid which can be formed of less material compared to conventional container lids, and a container having a hermetic seal between the lid and body without any separate polymeric seal material between them. The invention provides an improved connection between the lid and body, reduces the roll forming needed to connect the lid to the body, simplifies the seam connection between the lid and body, is of relatively simple design, and is economical to manufacture and assemble. A container of the present invention can be formed by a relatively simple method with apparatus that can connect the lid to the body in line or utilizing existing carousel structures used in conventional roll form applications for connecting the lid to the body.  
           [0010]    The invention can accommodate a plurality of seam connection designs between the lid and the body as needed for a particular application. The container forming method of the present invention is reliable, durable, permits real-time sensing of the quality of the connection between a lid and body, reduces rejected containers, reduces waste of product disposed in the containers, reduces down time of the assembly and filling line for the containers, can be automated, and can be readily adapted for use with conventional filling and beverage container assembly operations, although the process and apparatus is not limited to merely beverages. The methods and apparatus of the present invention can be used on filling lines for a wide variety of products including foods, chemicals, paints, cosmetics, automotive products, etc.  
           [0011]    These and other objects, features and advantages of this invention will be apparent from the following detailed description of preferred embodiments exemplifying the best mode known by the inventors at the time of filing. The description makes reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a fragmentary sectional view illustrating a double roll form connection between a lid and can body of a prior art container.  
         [0013]    [0013]FIG. 2 is a fragmentary sectional view illustrating a container having a lid connected to a body of the container according to the present invention.  
         [0014]    [0014]FIG. 3 is a fragmentary sectional view of a second embodiment of a container according to the invention having a modified connection between the lid and body.  
         [0015]    [0015]FIG. 4 is a fragmentary sectional view of a third embodiment of a container according to the invention illustrating a lid and body of the container prior to being laser welded together.  
         [0016]    [0016]FIG. 5 is a fragmentary sectional view of the container of FIG. 4 illustrating the lid and body after being laser welded together and roll formed to provide a smooth rim of the container.  
         [0017]    [0017]FIG. 6 is a fragmentary sectional view of a fourth embodiment of a container according to the invention illustrating a lid and body of the container prior to being laser welded together.  
         [0018]    [0018]FIG. 7 is fragmentary sectional view as in FIG. 6 illustrating the lid and body of the container after being laser welded and roll formed.  
         [0019]    [0019]FIG. 8 is a diagrammatic view of an apparatus according to the invention to connect a lid to a body of a container.  
         [0020]    [0020]FIG. 9 is a diagrammatic view of a modified apparatus according to the invention to connect a lid to a body of a container.  
         [0021]    [0021]FIG. 10 is a diagrammatic view of an apparatus for connecting a lid to a body of a container utilizing two lasers per container.  
         [0022]    [0022]FIG. 11 is a diagrammatic view of a laser welding system that employs moving mirrors to direct the laser beam toward the can lid and body joint of a can.  
         [0023]    [0023]FIG. 12 is a sectional view of another laser welding system that employs a conical reflector to form a ring-shaped beam that can be applied simultaneously around the circumference of a lid and body joint of a can.  
         [0024]    FIGS.  13 A- 13 C are a comparison study of the prior art container shown in FIG. 1 with two containers embodying the present invention.  
         [0025]    [0025]FIG. 14 is a sectional view of a laser welding system similar to that shown in FIG. 12 that employs a conical reflector to form a ring-shaped beam that can be simultaneously applied radially inwardly around the circumference a container. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    Referring in more detail to the drawings, FIG. 2 illustrates a metal container  10  having a generally cylindrical body  12  open at one end  14  and a lid  16  having an inner surface  15  and an outer surface  17 , fixed to the body  12  and closing its open end  14 . The body  12  of the container  10  has an upper edge portion  18 , which is rolled over and onto the outer surface  17  of a peripheral edge  20  of the lid  16  to preliminarily connect them together. Thereafter, the edges  18  and  20  of the lid  16  and body  12 , respectively, are irradiated by a laser beam to weld the lid  16  and body  12  together. Desirably, the weld is circumferentially continuous and provides a hermetic seal between the lid  16  and body  12 . Such a container  10  is ideally suited for use to contain products such as soup, soda pop, beer and the like.  
         [0027]    In more detail, the lid  16  is preferably a generally circular metal disk that is stamped or otherwise formed from a flat sheet. The lid  16  preferably has a generally planar central portion  22  surrounded by a circumferentially continuous channel or recess  24 , which is formed inboard of the peripheral edge  20  of the lid  16 . To locate the lid  16  and body  12 , an annular mandrel can be disposed in the recess  24  of the lid  16 . This arrangement can also be used to rotate the container relative to the laser beam and/or a roll forming tool.  
         [0028]    The body  12  of the container  10  has a generally cylindrical sidewall  30 , which is tapered or necked down toward an open end  14  and is preferably closed at its other end by an integral bottom wall (not shown). The body  12  can be formed, for example, by cutting a circular disk from a flat sheet of metal. Thereafter the disk is drawn into the generally cylindrical final shape in a manner well known in the art. Other can body forming techniques can be employed to for a body suitable for use in the present invention.  
         [0029]    As noted, the connection between the lid  16  and the body  12  is accomplished by laser welding the lid and body together, and roll forming the edge. These operations can be completed in different orders. For example, the upper edge  18  of the body  12  can be first rolled over the peripheral edge  20  of the lid  16  with the laser weld provided after this roll forming operation. Alternatively, the lid  16  can be disposed on a shoulder portion  21  of the body  12 , located inboard of the upper edge  18  of the body  12  as shown in FIG. 2. The peripheral edge  20  of the lid  16  can then be laser welded to this shoulder portion  21 . Thereafter, the upper edge  18  of the body  12  can be rolled over the peripheral edge  20  of the lid  16 .  
         [0030]    Regardless of the specific steps taken, the laser welded and roll formed connection provides a circumferentially continuous weld seam connection between the lid  16  and body  12  that comprises only three layers of material. Accordingly, the amount of material at the point of connection between the lid  16  and body  12  is substantially reduced from that of a container utilizing a double roll form connection between its lid and body which results in five layers of material at the seam connection.  
         [0031]    Beyond the material savings within the area of the seam connection, the lid can be designed to have a shorter or shallower recess  24  than is required in standard roll formed seam lids, further reducing the material required for the container  10  as a whole. For example, the axial height of the seam connection, as shown in FIG. 2 is substantially equal to the axial height of the central wall portion  22  of the lid  16 . Notably, as shown in FIG. 1, prior art cans  1  utilizing a double roll form connection  2  have a deep recess  7  with the upper edge  8  of the seam connection  2  far above the central wall portion  9  of the lid  3 . Such seam connection  2  is necessary for, among other reasons, to receive a mandrel which engages an axially inward facing surface of the lid  3  as it is moved from workstation to workstation to provide the double roll form, and to provide sufficient material for the double roll form. Further, with a shallower recess  24 , and because less material is needed in the seam connection of the container  10 , the sidewall  30  of the body  12  can be made shorter than is required for standard roll formed seam can bodies, further reducing the material of the container  10 .  
         [0032]    In one form, the container  10  is a beverage can with the lid  16  and body  12  formed from aluminum. To laser weld aluminum, intimate contact is needed between the components in the area of the laser weld. Accordingly, after the lid  16  is located on the body  12  a mandrel is preferably disposed on the lid  16  to provide a force pressing the peripheral edge  20  of the lid  16  onto the body  12  to firmly and intimately engage the lid  16  with the body  12  during laser welding. Alternatively, prior to laser welding, a single roll form connection can be provided between the lid  16  and body  12  to ensure their intimate engagement.  
         [0033]    Preferably, pure argon is used as the shield gas for the laser welding process. Argon is a relatively heavy, inert shield gas that enables a smoother finished weld with less roughness or jagged edges in the weld seam or puddle area. Desirably, in the first embodiment of container  10 , the weld can be made in the area of the recess of the lid. Accordingly, the relatively heavy argon shield gas can fill this area, to the extent not already filled by a mandrel, to provide an improved environment in the area of the weld during the welding process. This can further improve the quality and integrity of the weld.  
         [0034]    Any suitable laser apparatus can be used, with currently preferred lasers being Nd:YAG and CO 2  lasers. However, laser technology is rapidly evolving and it is anticipated that the desired laser can change and improve over current lasers. One current laser which performs satisfactorily is a Nd:YAG laser, Model No. GSI/Lumonics AM 356, from GSI/Lumonics of Northville, Mich. This laser is rated at 4 kW, produces a continuous beam, uses a 600 micron fiber and has eight fiber output capability.  
         [0035]    In conventional beverage can applications, a process speed of about 1500 cans per minute or greater is typical. In applications of the present invention in similar situations, the laser will likely be operated at between 500 watts and 2 kW, preferably between 750 watts and 1.2 kW. Such a laser apparatus provides a suitable weld of a typical beverage can having a lid formed of a non-ferrous material such as 5000 Series Aluminum about 0.008 in thick and a body formed of a non-ferrous material such as 3000 Series Aluminum about 0.006 in thick.  
         [0036]    Further, the power output of the laser is preferably variable in proportion to the processing speed of the can filling and assembly line. If the line slows down, the power output of the laser should be reduced to prevent overheating, undue melting or cutting of the lids  16  or bodies  20 . Likewise, if the speed of the line increases, the power output of the laser should be increased to ensure sufficient energy is applied to the cans that are more rapidly moving through the laser welding workstation.  
         [0037]    To achieve higher processing rates, more than one laser can be used. For example, as shown in FIG. 10, two generally opposed lasers  32 ,  32 ′ can be used to simultaneously weld one can with each laser welding about 185° providing a slight overlap of the welds to ensure the seam weld is circumferentially continuous. As another alternative, two lasers can be used to separately and simultaneously weld two different cans. Of course, more than two lasers can be used.  
         [0038]    A second embodiment of a container  50  according to the invention is shown in FIG. 3 and has a modified seam connection between its lid  52  and body  54 . In this embodiment, the container  50  has a generally upright upper edge  56  over which a peripheral edge  58  of the lid  52  is rolled either before or after the lid  52  is laser welded to the body  54 . The container  50  can be the same as container  10  in all other aspects. One advantage to this embodiment is that the peripheral edge  58  of the lid  52  is outside of the recess  24 . Products in the container such as soup, soda pop or beer, can collect in the recess  24  when being dispensed from the container. Desirably, in this embodiment, there is no abrupt edge within the recess against which or under which product or contaminants can collect.  
         [0039]    A third embodiment of a container  60  according to the invention is shown in FIG. 4. This container  60  has a lid  62  with a radially outer edge portion  64  outside of the recess  24  and extending generally perpendicular to a central axis  66  of the lid  62  and body  68 . The body  68  has a corresponding upper edge portion  70  extending radially outwardly from the sidewall  72 , generally perpendicular to the axis  66  of the lid  62  and body  68  and constructed and arranged to mate with the edge portion  64  of the lid  62 . With the edge portions  64  and  70  of the lid  62  and body  68  respectively intimately engaged, a laser beam can be directed onto the interface between these edges  64  and  70  to weld the edges together. One or both of the container  60  and laser beam can be rotated to provide a circumferentially continuous weld. As shown in FIG. 5, after the laser weld is provided, the mated edges  64 ,  70  of both the lid  62  and body  68  can be rolled over toward the body  68  to provide a smooth rim of the container  60 . Desirably, only a single roll form is needed and a hermetic seal is provided by the laser weld without any polymeric seal between the lid  62  and body  68 .  
         [0040]    A fourth embodiment of a container  80  according to the invention is shown in FIG. 6 to have a lid  82  with a generally upright peripheral edge  84  and a body  86  with a corresponding and mating upright edge portion  88  welded to the edge  84  of the lid  82 . The edges  84  and  88  of both the lid  82  and body  86  preferably extend generally parallel to the axis  90  of the lid  82  and body  86 . To provide the intimate engagement between the edges  84  and  88  of the lid  82  and body  86  required for a satisfactory weld, the edges  84  and  88  must be clamped together such as by separate mandrels  92  and  94  located on opposed sides of the edges. Thereafter, the edges  84  and  88 , and particularly an interface region of engagement between them, is irradiated with a laser beam to affect a weld between the lid  82  and body  86 . After the weld is formed, the edges  84  and  88  can be rolled over outwardly and downwardly as shown in FIG. 7 onto the body  86  to provide a smooth rim  96  of the container  80  that resists becoming fouled or contaminated.  
         [0041]    While the embodiments of FIG. 2 through  7  illustrate laser welding generally perpendicular to or parallel to a central axis of the lid and body of a container, it will be readily appreciated by those skilled in the art that these embodiments are merely illustrative of the broad aspects of the invention and other orientations of the lid, body and laser apparatus can be readily achieved to laser weld the lid and body in accordance with the present invention.  
         [0042]    [0042]FIG. 8 illustrates an apparatus  100  which can be used to rapidly and reliably connect lids to corresponding bodies of a plurality of containers  101  in an assembly line arrangement. In one form, a conventional seam forming chassis  102  can be used with modifications to add the laser apparatus  104 , the desired roll form tooling  106 , and sensors and controls to ensure proper operation of the apparatus  100 . The apparatus  100  can include a carousel  108  rotated at a speed corresponding to the speed of conveyors  110  upstream thereof such as by a variable speed motor. Containers  101  filled with product are provided to the carousel  108  one after another and are rotated with the rotating carousel  108  through various workstations to connect the lid to the body. As the containers  101  are transported by the carousel  108 , they also rotate about their center lines or axes  111  in a known manner. Therefore, in given rotation of the carousel  108  each can transported by the carousel  108  will rotate a given distance relative about its axis  111 .  
         [0043]    To provide a circumferentially complete seal between a lid and body of a container, the laser apparatus  104  can be selectively engaged and rotated with the carousel  108 . Desirably, the laser apparatus  104  can be rotated with the carousel  108  for a sufficient time to permit the container  101  to rotate one full revolution or slightly more about its central axis  111  to form a circumferentially complete weld. Thereafter, the laser apparatus  104  can backtrack to perform the weld of a lid and body of a subsequent container. In this manner, the laser apparatus  104  tracks with a particular container  101  until the container rotates at least one complete revolution about its axis  111  and then backtracks to the next consecutive container and so on.  
         [0044]    To accomplish the tracking and back tracking operation, the laser apparatus  104  can be mounted on a plate  112  which is attached to a crankshaft  114  timed off the rotation of the carousel  108 . The crankshaft  114  will permit the laser apparatus  104  to move through a specific and reciprocating path. The laser can also weld a subsequent can during its back track stroke or movement, although the back track movement will generally have to be at a slower speed because such movement is generally in the opposite direction of the movement of the cans.  
         [0045]    Real time monitoring of the laser power output will be needed to control the laser output relative to the rotational and translational (component of movement along path of conveyor or carousel) speed of the containers  101  to ensure that quality welds are being made. Downstream of the laser weld, one or more conventional roll form tools  106  can be used to provide the single roll form of the laser welded seam to provide the generally smooth rim of the container. Of course, the position of the roll form and laser weld tools can be switched such that the roll forming occurs upstream of the laser weld, if desired.  
         [0046]    It is also possible to provide the laser weld and any roll forming as the containers  101  are moved inline on a linear conveyor  120  as shown in FIG. 9, rather than via a carousel as described in connection with FIG. 8. Suitable mandrels or clamps engage the lids and bodies of the containers  101  and rotate individual containers  101  as they pass by a laser apparatus  122  and roll form apparatus  124  as needed. The laser apparatus  122  is moved in timed relationship with the conveyor  120  (such by a crankshaft driven off a drive wheel of the conveyor) to track with a container until the container is rotated at least one complete revolution about its central axis. Thereafter, the laser apparatus  122  can backtrack to the next consecutive container to be advanced along with that container and form the weld. Again, more than one laser can be used to weld each can, or to separately and simultaneously weld more than one can.  
         [0047]    Another laser apparatus  130  is shown in FIG. 11, which is suitable for use in welding the lids and bodies of containers  101  together as they are transported around a carousel  108 . All mandrels have been omitted from FIG. 11 to permit better visualization of the remaining portions of the apparatus. The laser  132  is situated at a fixed location conveniently positioned so that the beam  134  is directed toward a first mirror  136  and a second mirror  138 . The mirrors  136  and  138  are independently movable in at least one and preferable two directions by gimbaled mirror mounts  137  and  139 , respectively, so that the laser beam  134  can be variously directed. The exact location of the focal spot  140  of the laser beam  134  is controlled by signals generated by a controller, such as a p.c.  142 , which is coupled to the mirror mounts  137  and  139 . The focal spot  140  can be made to traverse the circumference of the joint region of the lid and body of each container as it is carried through a welding region by the carousel  108 .  
         [0048]    The linear welding speed of the focal spot  140  generated by the apparatus  130  can easily approach 250 m/min yet still achieve satisfactory welds using a low to moderate powered laser  132 . If still higher speeds are desired, additional laser apparatus  130  can be positioned at a slightly different location around the circumference of the carousel  108 , and additional sets of mirrors  136  and  138  provided and programmed so that welding is accomplished on every second or third can spaced around the carousel  108 .  
         [0049]    Another laser welding system  150  suitable for use in the present invention is shown in FIG. 12 to include a laser source  152 , which can take the form of an optical fiber  154  having an end  156  that is positioned on and directed along the axis Y of a container body  158 . A mandrel  160  includes a lid-carrying portion  162  for positioning a lid  164  on the container body  158 . The mandrel  160  also includes a conical reflector or director portion  166  having an upper end  168  coupled to the laser source  152 , and a lower end  170  forming a ring-shaped aperture for directing a ring-shaped beam  172  of laser power toward the joint between the body  158  and lid  164 . The mandrel  160  can also carry one or more lenses  174  for focusing the ring-shaped beam.  
         [0050]    An advantage of welding system  150  is the simultaneous application of the weld power around the complete periphery of the can and lid, thus reducing the opportunity for movement due to localized heating. If suitable power is available, the welding time may be shortened to just a “flash” or “snap shot”. It will be recognized by those skilled in the art that the conical reflector or director portion  166  acts to spread out the beam originally present in the source  152  or fiber end  156 , thus reducing the beam power density. To achieve the necessary heating to achieve welding with the system  150 , it will be necessary to employ higher-powered laser sources than in other embodiments. The fiber optic delivery of the power directly to the axis of the can being formed permits the adaptation of this system to a variety of line layouts.  
         [0051]    A comparison study of the prior art container  1  shown in FIG. 1 with two containers embodying the present invention is shown by the three views provided by FIGS. 13A through 13C. The prior art container  1  shown in FIG. 13A utilizes a roll formed connection  2  between the lid  3  and the body  4 . A deep recess  7  separates the central wall portion  9  of the lid  3  from the upper edge  8  of the seam connection  2 , which is located far above the central wall portion  9 . A first container  80   a  is shown in FIG. 13B, which is similar to that shown in FIG. 6, and has a lid  82  with a central wall portion  83  and a generally upright peripheral edge  84 . The container  80   a  also has a body  86  with a corresponding and mating upright edge portion  88 . The weld of the edges  84  and  88  and be accomplished with a variety of systems including the system  150  shown in FIG. 12. The savings in material that is achieved by changing from the container  1  of FIG. 13A to container  80   a  of FIG. 13B can be seen by merely comparing the amount of metal that appears above the upper surface of the central wall portions  9  and  83  of the two containers.  
         [0052]    Even additional savings in material can be achieved by adopting a container  50   a  shown in FIG. 13C that is similar to that shown in FIG. 3. The container  50   a  has a lid  52  and body  54 . The body  54  has a generally upright upper edge  56  over which a peripheral edge  58  of the lid  52  is rolled either before or after the lid  52  is laser welded to the body  54 . With the container  50   a , the laser beam for achieving the weld must generally have some radially inward component to achieve the necessary heating at the correct location. While the laser welding systems shown in FIGS.  8 - 11  are suitable to accomplish this, the system  150  shown in FIG. 12 is not as desirable unless modified to have the radially inward component.  
         [0053]    Such a modified system  150   a  is shown in FIG. 14. The system  150   a  includes a conical reflector or director portion  166  having an upper end  168  coupled to the laser source, and a lower end  170  forming a ring-shaped aperture that is similar to but somewhat larger than that shown in FIG. 12. A ring shaped mirror  178  is positioned to redirect the ring-shaped beam  172  of laser power toward the joint between the body  54  and lid  52 . The ring shaped mirror  178  can be either fixed or movable relative to the conical reflector or director portion  166 . One or more lenses  175  can be included for focusing the ring-shaped beam.  
         [0054]    Desirably, any of the previously described apparatus can use a substantial portion of an already existing assembly line including a mechanism which places and locates the lids on the bodies and even some of the mandrels which currently engage the lid and body during the conventional double roll form seam connection between a lid and body. As described above, the apparatus can even use the rotating carousel of an existing seam forming apparatus and the various conveyors which transport the containers to and from the carousel. Desirably, the apparatus does not require any mechanism to place and locate a polymeric seal between the lid and body because such a seal is not needed due to the hermetic seal provided by the laser weld. Further, the rotating carousel can be removed and the laser weld can be formed in-line, if desired.  
         [0055]    Accordingly, containers and methods and apparatus for forming the containers are provided by the present invention that significantly reduce the amount of material required to form the container, eliminates a separate polymeric seal needed in conventional containers, and eliminates at least some of the roll forming operations required to connect the lid to the body of the container. Desirably, controls and sensors can be provided to monitor the quality of weld of individual containers. Any unsatisfactory welds or containers can be individually removed from the assembly process thereby greatly reducing the number of rejected or scrapped containers and consequently greatly reducing the amount of product wasted. Still further, real time adjustments to the laser apparatus can automatically correct the laser output after a reject or problem is detected to reduce the number of containers that are defective and must be rejected. The laser welding can provide a fast, durable, reliable weld that has significant practical and economical advantages over the current container utilizing a double roll form connection between the lid and body.  
         [0056]    Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.