EP2303719A1

EP2303719A1 - Can body and method and apparatus for the production thereof

Info

Publication number: EP2303719A1
Application number: EP09768690A
Authority: EP
Inventors: Werner Boltshauser
Original assignee: COSMOCAN Tech AG
Current assignee: COSMOCAN Tech AG
Priority date: 2008-06-25
Filing date: 2009-06-23
Publication date: 2011-04-06
Also published as: JP2011525458A; WO2009155721A1; BRPI0915410A2

Abstract

On a can body (1), comprising a can casing (3), which is closed around the can axis and comprises a metal layer, and a closure part (13, 33, 56), which comprises a metal layer, a laser connection is produced between the metal layers of the can casing (3) and the closure part (13, 33, 56) in an overlapping region of the closure part (13, 33, 56) and the can casing (3). The laser connection comprises a plurality of perforations along the connecting line, or a plurality of narrowly delimited regions, in which the two metal layers are melted together. A plastic material (3b, 7a, 13d, 15, 54, 58) is arranged on the laser connection. The laser connection ensures stability, and the plastic material (3b, 7a, 13d, 15, 54, 58) ensures leak tightness, of the connection between the can casing (3) and closure part (13, 33, 56).

Description

Can body and method and apparatus for producing the same

The invention relates to a can body according to the preamble of claim 1 to a method for producing can bodies according to the preamble of claim 10 and to an apparatus for producing can bodies according to the preamble of claim 13.

Aerosol can bodies are formed in one or more parts. In one-piece aerosol aluminum cans, a cylindrical can body is provided by cold extrusion. Subsequently, a valve seat is formed at the open end by upset necking. This manufacturing process is very expensive due to the required for the many processing steps and the water and energy requirements for cleaning and drying. US Pat. No. 4,095,544 and EP 0 666 124 A1 describe the production of seam-free steel cans. In this case, the cylindrical can body is produced by means of stamping, pressing and ironing out of a tin or plastic-coated steel sheet. It has been found that enormous problems occur when forming a narrowed can neck, because the material structure is changed or hardened by the stretching.

Also widely used are can bodies made of sheet steel, in which the shell has a longitudinal weld. The bottom and the upper end are fastened to the can jacket via seam connections. When seaming joints sealing problems can occur, which are reduced approximately with sealing rings. In the usual extremely thin-walled cans arise with frontally arranged seals problems.

WO 05/000498 discloses a solution in which a can bottom is fastened to a laser seam on the bottom end side on a can jacket closed with a pushed laser longitudinal seam. At the upper end a narrowing is formed. For this purpose, a form roller is pressed against the rotating can jacket from the outside. Inside the can jacket, a support edge is arranged, which cooperates with the forming roller during the narrowing and is moved in the direction of the upper end side. At the narrow end, a closing element with a valve seat is welded firmly. Optionally, the upper end of the can jacket is narrowed by upset necking or spin-flow necking, whereby this restriction can be carried out until the valve seat is formed. The valve seat is formed by the outwardly formed can end, wherein the valve seat in a sectional plane which comprises the can longitudinal axis is substantially circular. The free end extends from the inside to the outside and from the outside back against the outside of the narrowed can jacket. The valve seat is a so-called outward curl, or an outward edge curl.

From WO05 / 068127 a solution is known in which a can jacket is pressed radially outwards onto an inner mold with a longitudinal laser seam for shaping. At the lower end of the can jacket a can bottom is welded firmly. On the upper end side, a terminating element with valve seat is arranged with a laser seam. Optionally, instead of the upper end member at the upper end of the can jacket, a constriction process such as Stitch Necking or Spinning Flow Necking is performed. This constriction can be carried out until the formation of the valve seat. The illustrated embodiments show outward curls, and outward edge curls, respectively.

The present invention has for its object to find a solution with the stable and tight cans can be easily and inexpensively manufactured.

This object is solved by the features of claim 1, claim 10 and claim 13. The dependent claims describe preferred or alternative embodiments.

For fastening a closure part arranged on an end side of the can wall, solutions are known from the prior art in which a dense annularly closed weld seam is produced by means of a laser weld seam. It has been found that in such continuous laser welding seams, the adjoining contact areas of the two parts to be joined together should have no contamination and no coatings. Otherwise, there is a risk that components of the contaminants or coatings explode into the gas state due to the large heat generated in the seam area, thereby creating interruptions and therefore leaks in the seam. To overcome this disadvantage arises for arbitrary doses, the task of finding a compound in which emanate from small impurities or coatings no interference of the compound. In solving this problem, it was recognized in a first step that the metallic layer of the can jacket, the metallic layer of the termination part and the laser connection between these layers only have to ensure the stability of the can. The tightness can be achieved by a coherent inner coating or plastic material in the laser connections, wherein the plastic material is tightly connected to the two parts.

In a second step it was discovered that a laser connection with many interruptions along the connecting line or with a large number of narrow areas in which the laser beam has fused the two metallic layers together generates less heat and the danger of explosive gas evolution is greatly reduced.

This solution with the multitude of narrow metallic connection points and the sealing plastic material can be used advantageously in all can shells and end elements with a metallic layer and is thus not limited to aerosol cans and of course not to special aerosol cans with an inward edge flanging ,

Another advantage of such a circular laser connection with a number of narrow connection areas is that it can be performed by means of a laser scanner device. That is, the laser beam is guided, for example, by mirror movements along the connecting line, whereby the laser is alternately transmitted or interrupted and fertilize and break accordingly. Due to the possibility of scanning, turning the can past the exit point of the laser can be dispensed with. Also, the laser exit head does not have to be moved along the connection line.

If the can neck or the valve seat of an aerosol can is produced as a separate part and then connected to a narrowed can jacket, then, according to a preferred embodiment, the welded connection is carried out with welding areas interrupted in the direction of contact, in particular with punctiform welded areas.

Such a broken weld joint can also be advantageously used to attach the can bottom to the can jacket. The bottom of the can - A - seninneren fro pressed against a narrowed end portion of the can jacket and then set slightly overlapping with a broken laser connection at the narrowed area. If, for example, there is no access at the end of the can jacket facing away from the bottom of the can to bring a bottom of the can into the interior of the can jacket and then to the desired attachment region, there is a possibility of a can bottom directly at its attachment region through the constriction into the interior of the can To bring can jacket.

Because the radius of the can bottom is greater than the radius of the opening at the narrowed mounting area of the can bottom, the round cross section of the can shell is formed at the mounting area of the can bottom with a small pressure, or by crushing, into an oval-shaped free cross-section. In this case, the opening cross-section increases in a first direction and decreases in the second direction perpendicular thereto. Now, if the can bottom is tilted to the level of the oval opening, it can be inserted into the interior of the can jacket and pressed after insertion and tilt back from the inside of the constriction. In the overlap area, the can bottom can be fixed to the can jacket with a laser connection with interruptions. With ring-shaped or disc-shaped plastic material inside along the laser connection, a continuous and dense inner coating can be achieved.

In the case of longitudinal seams, the heat peak flowing along with the seaming leads to unwanted fraying at the material end, where it can no longer flow in the longitudinal direction. This problem does not occur when long continuous longitudinal seams are formed and the can jackets are separated from the resulting tube. It has now been found that the problem in producing can coats from jacket blanks or panels can also be solved by forming a laser connection with many interruptions along the connecting line instead of a continuous laser seam. The interruptions prevent the flow of heat and therefore heat propagation problems at the end of a compound, or a jacket blank are excluded. Such a can jacket longitudinal connection comprises a multiplicity of narrow areas in which the laser beam has fused the two overlapping metallic layers together. If the material of the can jacket is coated on the inside and a continuous inner coating of the can jacket is desired, the inside of the can The longitudinal seam of plastic material is arranged lengthwise and this is tightly connected to the inner coating on both sides of the seam.

According to a further embodiment, the can jacket is formed with a formed valve seat by a radially expanding pressing step on an inner mold, wherein the inner mold preferably corresponds to a desired final shape of the can jacket. The inner mold may have any of the cylindrical shape deviating shapes and decorative structures. In this case, the valve seat and held over this the can jacket during pressing in the inner mold. The valve seat is not expanded. By holding the can jacket on the valve seat, a defined position of the can jacket is ensured relative to the inner mold. For pressing, an elastic pressure mandrel which can be acted upon by pressure fluid is introduced into the can jacket.

When molding in the inner mold can be formed at the free end of the can jacket, which faces away from the valve seat, a shape corresponding to the connection area of a can bottom. The can bottom is then attached to the can jacket with a laser connection.

According to a further embodiment, if appropriate, the free end of the can jacket assigned to the bottom of the can is placed on the outer mold only after insertion of the can bottom. This procedure is possible at all doses, in the production of a can jacket is connected to a bottom of the can. For the narrowing of the can end after the insertion of the can bottom, a rolling method is preferably used. In this case, a rotating roller is moved relative to the can jacket around its circumference. At the introduced and held there can bottom and preferably also on the forming roller, the desired constriction contour for the constriction of the can jacket is formed. During the rolling process, the can jacket is pressed tightly against the contact area of the bottom of the can.

The end face of the can bottom lies in the inside of the can or on the inside of the can and the end face of the can jacket outside the can jacket or on the outside of the can. If the outside of the can jacket is provided with a decor, the decor extends down to substantially the floor space. The box is therefore aesthetically appealing and stands out from cans in which the curvature of a cylindrical jacket to the bottom of the can is not provided with a decor. Thus, the shoulder-shaped mating portions of the can bottom and the can jacket, in which the cross-section decreases against the front side of the can jacket, completely close to each other, the inner Dosenbo- may possibly very little in the direction of the can axis are moved against the outside, said fitting area of the can jacket minimally widened and is brought into close contact with the bottom of the can. In the area with this dense contact, a ring-shaped closed laser connection between the can jacket and the bottom of the can can be attached.

In the context of the invention it has been recognized that a circumferential laser seam between the overlapping regions of the can bottom and the can jacket, in particular at the front side of the can jacket, need not necessarily be tight. The laser circumferential seam primarily fulfills the task of stably bonding the can jacket to the bottom of the can. Even with a dose of internal pressure required for aerosol cans, the seam must not burst. It has been shown that a stable connection, which is not tight with certainty, is achieved with significantly less effort than an absolutely dense laser peripheral seam. This is because the laser peripheral seam is very narrow, for example substantially 0.15mm wide. If there is little contamination on one of the parts to be joined in the region of the seam, then there is an explosive evaporation of contamination components, in particular of grease or oil components, during welding. At these points, there may be brief breaks in the laser circumferential seam.

Because the can bottoms are preferably fabricated at another production site, optionally with a lubricant manufacturing or molding process, contaminants from manufacturing or transportation can hardly be completely eliminated with reasonable effort. However, it is possible with little effort to install a barrier in the can interior between the bottom of the can and the bottom of the can, which tightly closes the can interior in the laser welding seam to the outside. Because the possibly leaky points of the laser circumferential seam are extremely small passages, the barrier does not have to absorb particularly large forces.

Between the can jacket and the bottom of the can in the area of a laser peripheral seam, or a laser connection with a number of narrow According to a further preferred and independent of the claimed in the independent claims Invention inventive solution in the can interior along the entire circular laser peripheral seam or laser compound plastic material arranged , which is tightly connected to the bottom of the can and to the can jacket. This excludes access from the inside of the can to the circumferential laser seam or laser connection. The laser peripheral seam or laser connection ensures the necessary strength and the plastic material connected to the bottom and the can jacket the tightness.

The plastic material along the laser peripheral seam can be placed on the bottom of the can as ring or plate with ring edge, sprayed on with a nozzle or also be built up in an injection molding step on the bottom of the can. Before or after the formation of the circumferential laser seam, a heat-bonding step achieves a tight connection of the ring to the can jacket and optionally to the bottom of the can on both sides of the laser peripheral seam.

The sealing plastic material along the laser peripheral seam between bottom of the can and can jacket is then used particularly advantageously when the can jacket has a plastic layer inside, in the form of a coating or preferably a foil. A can bottom with a plastic inner layer facing the can interior, projecting along the radially outer edge against the can interior and upwardly over the metallic edge region of the can bottom, can be inserted into the cylindrical can shell with the plastic inner layer. After insertion, a radially outer contact region of the plastic layer of the can bottom bears against the inner layer of the can jacket.

Various embodiments and steps of merging the areas of the can jacket and the terminating element in the laser connection are possible. This is confirmed by the following examples.

If the can jacket is somewhat narrowed at the end region where the bottom of the can is arranged, the bottom of the can has a slightly larger outside radius than the passage opening of the narrowed region. If the round cross-section of the can jacket is deformed into an oval cross-section at the attachment area of the can bottom with a small pressure, or by means of squeezing, the opening width increases. ing cross section in a first direction and decreases in the perpendicular thereto second direction. The can bottom is tilted to the plane of the oval opening slightly about an axis that is substantially parallel to the first direction, and then inserted into the interior of the can jacket. After insertion, it is tilted back and pressed against the constriction from the inside. In the overlap area, the can bottom can be fixed to the can jacket with a laser connection. With ring-shaped or disk-shaped plastic material inside along the laser connection, a continuous and dense inner coating can be achieved.

As described above, the end portion of the can jacket can be formed with a forming step to a shoulder-shaped contact surface of the can bottom and fixed with a laser circumferential seam. With a heat treatment step, the plastic layer of the can bottom is connected in the contact region to the inner layer of the can jacket with this. For this purpose, the plastic layer of the can bottom optionally comprises sealing material at least in the region of the desired connection. The heat treatment step is optionally carried out prior to the forming step, so that the can bottom already adheres to the can jacket during forming.

If it is to be dispensed with a transformation of the can jacket at the bottom of the can after insertion, it can be formed on the can jacket a ringnutförmiger receiving area for a corresponding outwardly projecting Kantaktbereich the can bottom. The bottom of the can should be pressed from the outside or down against the can jacket, so that the Kantaktbereich the can bottom passes into the receiving area of the can jacket and is held therein. There is now an externally convex Ringnutbereich the can bottom in a concave from the inside annular groove portion of the can jacket. The end face of the can bottom lies in the inside of the can or on the inside of the can and the end face of the can jacket outside the can jacket or on the outside of the can.

At the free lower end of the can jacket, so at the bottom of the can, the cross-section of the can jacket against the top little increases and then again. The lower cross-sectional constriction must be very small, so that the bottom of the can with the maximum outside diameter can be pressed into the interior of the can jacket. When pressed in, the jacket area will expand slightly at the lower cross-sectional constriction and / or the bottom of the can will narrow slightly at the maximum outside diameter. When pressed in can bottom lies along the velvet circumference, a shoulder of the bottom of the can inside to a corresponding shoulder of the can jacket. In this shoulder region, the cross section from the free end of the can jacket decreases so far that a stop is formed. The laser peripheral seam is formed in a circular closed manner along the shoulder regions which are pressed against one another. After the narrowed shoulder region, the diameter of the can jacket increases again. From the outside of the can jacket at the shoulder area and directly above a recess groove can be seen.

It is advantageous if the contact area of the bottom of the can is inserted into the interior of the can jacket. The thickness of the can bottom is usually chosen slightly larger than the thickness of the can jacket. Accordingly, the shoulder area of the bottom of the can is somewhat more dimensionally stable than the shoulder area of the can jacket. An optimal press fit is achieved when the more stable shoulder area is pressed from the inside against the slightly less stable shoulder area. If necessary, the outer shoulder area is somewhat stretched in the circumferential direction, but the inner and more stable shoulder area is not deformed or compressed. If the can jacket were on the inside and the more stable bottom of the can, compressive creases could form in the can jacket due to the pressing force, which would prevent a dense circumferential laser seam.

In order to ensure a continuous inner coating during the transition from the can jacket to the bottom of the can, the bottom of the can is coated on the inside and provided with a meltable sealing bead. The can jacket is coated on the inside with a film, wherein the shoulder area for the connection to the bottom of the can has no coating. The bottom of the can has no coating on its outside facing away from the inside of the can, at least in the shoulder region. The laser peripheral seam is now formed between directly adjacent metallic region of the can jacket and the bottom of the can. In order to coat the inside of the can end of the bottom of the can and the subsequent uncoated area of the can sheath, the meltable sealing bead is heated and made to flow and then solidified that the material of the sealing bead a complete connection between the inner coatings of the can jacket and of the can bottom.

In order to provide a protective layer on the underside of the can, an outer bottom cover, preferably in the form of a plastic bottom, at the bottom can fixed. When the bottom cover extends slightly from the bottom of the can along the can wall, it can engage the recessed groove directly above the laser perimeter seam. The bottom cover covers the lower front side of the can jacket and the laser circumferential seam. When the bottom cover at the recess groove is tightly connected to the can jacket and the can wall comprises an outer foil, the metallic layer of the can jacket and the can bottom are sealed to the outside and oxidation problems can be eliminated. Because the bottom cover preferably spans the entire bottom of the can, can be dispensed with an external coating of the bottom of the can.

The various processing steps can be performed on turntables, but this is relatively complex due to the synchronized transfers and tuned to the can diameter holding and transfer elements. The required throughputs can also be achieved advantageously with solutions in which a plurality of linear processing lines are provided in parallel. Dust areas can be provided in front of the individual processing stations, of which the partially assembled can bodies are guided into the parallel processing lines. If the production of cans with a first one is changed over to cans with a second diameter, then with parallel linear processing lines only a few elements have to be adapted to the changed diameter.

With the inventive method steps, it is possible to produce cans with very thin can coats. To produce the can shells, steel sheet having a thickness of substantially only 0.16mm can be used. Optionally, sheet metal with thicknesses between 0.16 and 0.12mm can be used.

In a can body according to the invention with a can jacket closed around a can axis and comprising a metallic layer, and a closure part comprising a metallic layer, a laser connection between the metallic layers occurs in an overlapping region of the closure part and the can jacket along a connecting line the can jacket and the end part formed. The laser connection includes many interruptions along the connecting line or a plurality of narrow areas in which the two metallic layers are fused together. In the laser connection, a plastic material is arranged. The laser connection ensures stability and the plastic material, the tightness of the connection between the can jacket and end part.

In the method according to the invention for producing an inventive can body, a laser connection is formed between the metallic layers of the can jacket and the closure part with many interruptions along the connecting line or with a plurality of narrow areas in which the two metallic layers are fused together. In the laser connection, a plastic material is arranged, whereby the laser connection ensures the stability and the plastic material the tightness. The regions in which the two metallic layers are fused together are preferably processed with a laser scanner device, wherein a laser beam is guided, for example, by mirror movements along the connecting line or along the overlap region and alternately emitted or interrupted, so that connections and interruptions occur ,

A device according to the invention for producing an inventive can body comprises a laser welding device and a holding device for holding the can jacket and the closure part, wherein the laser welding device comprises a scanning laser device, which in the overlapping region at a plurality of narrow areas with a scanner Laser beam fuses the two metallic layers together. The scanner laser device comprises a controller, a laser source, which provides the scanner laser beam for the desired time periods, and at least two mutually perpendicular axes rotatable mirrors or reflecting surfaces, wherein the scanner laser beam from the laser source via the two rotatable mirrors or Reflection surfaces reaches the respective desired location of the overlap region and the holding device holds the can jacket and the end part in a fixed position.

The drawings illustrate the inventive solution based on embodiments. It shows

1 a, 1 b, 1 c show vertical sections through the connection of the upper end part with the can jacket, FIG. 1 d shows a detail of a plan view of the connection of the upper end part with the can shell, 2 is a schematic representation of a device for connecting the upper end part with the can jacket,

3 shows a schematic illustration of a scanner laser device when forming a circular laser connection; FIG. 4 a shows a vertical section through a detail of the connection of the can bottom to the wall of the can;

4b is a plan view of a section of the connection of the can bottom with the can wall,

5a, 5b, 5c vertical sections through the can jacket and the bottom of the can when inserting the can bottom,

6a, 6b, 6c are schematic plan views of the can jacket and the bottom of the can when inserting the bottom of the can,

Figure 7a is an end view of a can jacket made from a panel with a laser bond; Figure 7b is a side view of a can jacket made from a panel with a laser bond

8a, 8b enlarged sections of vertical sections through the laser connection of a can jacket,

FIGS. 9a and 9b show vertical sections through a section of the connection of the can bottom to the can wall, and FIGS

10 shows a vertical section through a beverage can, wherein left and right variant embodiments are shown in which the layers of the can jacket and the closure part are different in the overlapping area,

1a, 1b, 1c and 1d show the upper to a neck portion 4 narrowed end of a can jacket 3, which is held by a holding device, not shown. On the inside of the can jacket 3, an inner film 3b and on the outside of an outer film 30 or an outer coating is arranged. From below, a holding mandrel 34 raises the upper end part 33 against the upper opening of the can jacket 3. The upper end part 33 comprises a valve seat 5 with an inward edge flange 6 and with a sealing ring 7 inserted in the inward edge flanging 6 To ensure positioning and pressing of the upper end part 33 on the neck part 4, the retaining dome 34 comprises a centering projection 34a and a contact surface 34b. The upper end part 33 is pressed with the overlap region 33a adapted to the constriction of the nozzle shell 3 by the contact surface 34a against the corresponding surface of the neck part 4. In order to connect the upper end part 33 firmly and tightly with the can jacket 3, an upper pressure ring 36 is attached to the neck part 4 from above. A heating device 36a is configured and arranged such that heat can be conducted to the outer connection region 35b of plastic material 7a, whereby a heat-seal connection is formed between the upper connection region 35b of the plastic material 7a and the inner film 3b. If the plastic material 7a is formed integrally with the sealing ring 7, a continuous inner coating is produced from the inner foil 3b to the sealing ring 7.

In the overlap region 33a, a scanner laser beam 37 is used to connect a metallic layer of the can jacket 3 to a metallic layer of the upper end part 33. The resulting laser connection comprises in the overlap region 33a a plurality of narrow connection points 38, in which the laser beam has fused the two metallic layers together. It has been shown that the material of the inner foil 3b when pointwise introducing the laser energy from the center of the laser beam goes away and connect the two metallic layers without interference on the bolt-shaped fused and solidified melt areas 39 together. The time and power with which the laser beam generates a connection point 38 is selected so that the melting region 39 does not completely pass through the metallic layer of the upper end part 33 and the plastic layer 7a is not impaired. There are different grid and possibly different cross sections of connection points possible, wherein at least one row along the circumference is necessary. By means of the control of the scanner laser, the arrangement and shape of the connection areas or connection points can be changed with little effort.

Fig. 2 shows an embodiment of a device for connecting the upper end part with the can jacket. On a circumferential chain or belt device 40 projecting retaining mandrels 34 are fixed with a centering projection 34a and a contact surface 34b, wherein a plurality of rows of retaining mandrels 34 can be arranged side by side to parallel multiple cans 3 to provide upper end elements 33. In a first loading area 42 upper end elements 33 are placed on the retaining mandrels 34. In a second loading area 43 canned shells 3 are placed on the retaining mandrels 34 via the upper end elements 33. An upper contact pressure ring 36 is attached from above to the neck portion 4 of the can jacket 3 and achieved with a heater sealing connection from the connection portion 35b of the plastic material 7a to the inner film of the can jacket 3. Subsequently, with a scanner laser beam 37, a metallic layer of the can jacket 3 with a metallic layer of the upper end part 33 connected. Because neither the can parts rotated nor the laser source must be moved in a circle, the laser connection system can be easily constructed. In the delivery area 45, the can jacket 3 is delivered with the upper end part 33 for transport to another can processing station.

Fig. 3 shows a scanner laser device 46, which forms a laser connection with the scanner laser beam 37 along a circular line with a plurality of narrowly defined areas in which the laser beam has fused two metallic layers together. In the illustrated treatment step, a can bottom 13 is pressed from the inside to a lower constriction of the can jacket 3 and fixed with the laser connection. Inside the can, a holding mandrel 34 'presses the can bottom 13 against the narrowing of the can jacket 3, the can jacket 3 being held by the contact pressure ring 36 against the can bottom 13.

The scanner laser beam 37 passes from a laser source, not shown, via two mirrors 47, which are rotatable about mutually perpendicular axes, to the annular area in which the laser connection is to be formed. A control, not shown, and two drives 48 actuate the Drehausrichtung the two mirrors 47th

It goes without saying that with the scanner laser device 46 instead of the bottom of the can and another end element can be attached to the can jacket 3. In addition, the end element could also be arranged on the outside of the can shell. Thus, this solution is not limited to aerosol cans and of course not to special aerosol cans with inward edge flanging.

Figures 4a and 4b show a laser connection made with the scanner laser device 46. In the region of overlap of the interconnected parts, this comprises a multiplicity of narrow connection points 38, in which the laser beam has fused the two metallic layers together. It has been shown that the material of the inner film 3b when punctually introducing the laser energy away from the center of the laser beam and connect the two metallic layers without interference on the bolt-shaped fused and solidified melt areas 39 together. Various rasters of connection points are possible, with at least one row being necessary along the circumference. By means of the control of the scanner laser, the arrangement and shape of the connection areas or connection points can be changed with little effort.

The can jacket 3 is narrowed somewhat shoulder-shaped at the bottom of the can 13. The bottom of the can 13 has a correspondingly shaped overlap area, which is firmly welded to the laser connection at the narrowed area of the can jacket 3. Inside the can, plastic material 15 is arranged along the circular laser connection, which is tightly connected to the can bottom 13 along a lower connection region 15a and to the can jacket 3 along an outer connection region 15b. The plastic material 15 can be placed as a ring or plate with ring edge on the bottom of the can 13, sprayed with a nozzle or built in an injection molding step on the bottom of the can 13. If a central deck area of the plastic material 15 covers the middle area of the bottom of the can 13, it is possible with little effort to produce a can body 1 whose entire inner surface has a plastic layer.

The lower end region of the can jacket 3 is applied tightly to the shoulder region in the overlapping region of the can bottom 13. The peripheral end face of the can bottom 13 lies in the inside of the can or on the inside of the can and the bottom end face of the can jacket 3 outside the bottom 13 of the can.

5a, 5b and 5c and 6a, 6b and 6c show the insertion of a can bottom 13 through the narrowed end portion of the can jacket 3. When the can jacket 3 is slightly narrowed at the end portion where the can bottom 13 is placed, the can bottom 13 has a slightly larger outer radius than the passage opening of the narrowed area.

In FIGS. 5b and 6b, the cross section of the can jacket 3 has been converted into an oval cross-section with a small pressure, or by means of squeezing. In this case, the opening cross-section increases in a first direction and decreases in the second direction perpendicular thereto. The can bottom 13 is held by an insertion holder 49, wherein preferably in a suction contact region 49a to the sheath a negative pressure is generated. Upon insertion, the can bottom 13 is tilted slightly from the insertion holder 49 to the oval opening plane about an axis substantially parallel to the first direction. In the tilted position, the can bottom 13 is inserted into the interior of the can jacket 3.

Fig. 5c and 6c show a situation after tilting back of the can bottom 13 by the vertical alignment of the Einführhalters 49. To press the can bottom 13 even after removing the Einführhalters 49 from the inside to the constriction, the upper end face of the retaining mandrel 34 'against the Pressed can bottom. In the overlapping area, the can bottom 13 can be fastened to the can jacket 3 with a laser connection.

The new and inventive laser connection, with a plurality of narrow areas where the laser beam has fused the two metallic layers together, is not limited to the connection of a terminating element to the can jacket, also independently of the invention claimed in the independent claims 3 can be used advantageously. With reference to FIGS. 7a, 7b and 8a, 8b, a can jacket 3 produced from a panel with a laser connection will be described. The panel is formed into a tube, wherein the two associated lateral areas in an overlap region 50 along the laser connection slightly overlapping abut each other.

With a laser, a laser connection 51 is formed in closely adjacent lateral regions, this connection consisting of a multiplicity of narrowly delimited connection regions. In this case, the can jacket 3 can be moved relative to a laser exit point or the point of impact of a scanner laser beam 37 can be moved along the overlap region 50.

If the interior of the can jacket 3 does not have to be completely separated from the metallic layer of the can jacket 3, then a connection according to FIG. 8a is sufficient, where an inner end side of the metallic can jacket layer is accessible from the inside of the can.

In order to ensure a complete inner coating, is on the metallic layer of the panel for the can jacket 3, an inner foil 3b or a plastic coating and on the first end face to lie in the interior of the can jacket 3 comes, a plastic strip 52 arranged. A first connection surface 52a of the plastic strip 52 is connected via an adhesive or sealing connection directly to the inner film 3b or to the coating at the first end side. After forming the can jacket, a second connection surface 52b of the plastic strip 52 abuts the inner film 3b in the vicinity of the second end face of the metallic layer of the panel. With a sealing or adhesive connection, the second connection surface 52b is also connected tightly to the inner film 3b or coating. Cans with this compound can be advantageously used in the manufacture of any three-piece cans. Three-piece cans with a can jacket with a laser longitudinal connection 51 with a plurality of narrow connection areas and a plastic bar 52 tightly connected to the inner film 3b or the coating can be easily manufactured with high quality.

Fig. 9a shows a laser connection made with the scanner laser device 46 between a can jacket 3 and a can bottom 13. This includes in the overlapping region 53 of the interconnected parts 3, 13, a plurality of narrow connection points 38, in which the laser beam, the two metallic layers of the can jacket 3 and the closure part or the can bottom 13 has fused together.

The overlap region 53 is closed annularly and extends in cutting planes which comprise the can axis 2 preferably at an angle in the range of 5 ° and 85 °, in particular 20 ° to 70 °, but preferably 30 ° to 60 ° to the can axis 2. As a result, with a contact force acting between the two parts in the overlapping region 53, a tight abutment of the two parts to be joined can be achieved. In these sectional planes, the can jacket 3 in the overlapping region 53 extends from one side to its end face 3c at one end of the can jacket 3. The outer edge region of the closure part extends from the other side to the radially outer end face 13c of the overlap region 53 In the overlapping region 53, the can jacket 3 and the closure part have substantially the same shape, so that they each abut each other with one layer without a gap. In the illustrated embodiment, both parts have only one layer in the overlapping area.

The plastic material required for the tightness in the laser connection is formed by an outer coating 54 of the can bottom 13. So that the external coating 54 in the overlapping region or in the laser connection with both the bottom of the can 13 and the can jacket 3 is tightly connected, a heat treatment is preferably carried out in the overlap region. In order to be able to secure a consistently tight connection of the outer coating 54 to the can jacket 3, the outer coating 54 comprises a sealable layer which can be connected to the can jacket 3 at least in the overlapping region and the connection of the outer coating 54 to the metallic layer of the can bottom 13 is likewise a firm and tight connection. The outer coating 54 forms at the bottom of the can 13 a corrosion protection, which is advantageous in cans made of steel, because then they do not rust on moist shelves.

It has been shown that the material of the outer coating 54 moves away from the center of the laser beam when the laser energy is introduced at a point, and the two metallic layers bond to one another without interference via the bolt-shaped melted-together melted regions 39. Around the solidified melting regions 39, the outer coating 54 remains as a sealing layer running along the overlapping region 53 and achieves the desired sealing function. There are various rasters of connection points 38 possible, wherein at least one row along the circumference is necessary. By means of the control of the scanner laser, the arrangement and shape of the connection areas or connection points 38 can be changed with little effort.

In the embodiment shown in FIG. 9a, neither the can bottom 13, or the closing element, nor the can jacket 3 is coated on the inside of the can. Such uninsulated cans 1 can be used for all products in which no undesirable reactions between a metallic layer of the closure element or the can wall 3 and the product are expected, which is the case, for example, with polyurethane foams for building applications.

The embodiment of the laser connection shown in FIG. 9 a can also be selected analogously for an upper terminating element, in which case the upper terminating element or optionally the can jacket 3 has a plastic coating at least at the overlapping region 53.

Fig. 9b shows an embodiment of the connection between the can jacket 3 and a termination part, in particular a bottom 13, in which connection the radial outer end surface 13c of the inner part of Doseninnem ago is not accessible, because an edge region at the radially outer end face 13c is folded over by 180 ° to the outside. When the folded-over edge area is applied to the other part in the overlapping area 53, the end face 13c is no longer accessible after the laser connection or connection points 38 have been formed. If the can jacket 3 comprises an inner film 3b and the closure part or the can bottom 13 comprises an inner coating 13d, a continuous inner coating is formed and the plastic material of the inner film 3b and the inner coating 13d produce the impermeability. It goes without saying that also the end portion of the can jacket can be folded outwards accordingly, when the final part is applied outside the can jacket 3.

Fig. 10 shows an embodiment in the form of a beverage cans 55, wherein the can bottom is formed together with the can jacket 3 as a deep-drawn cup-shaped part. At the upper open end of the can jacket 3, the upper end portion 56 is arranged with a Aufreisseinrichtung 57. The laser connection between can jacket 3 and upper termination member 56 includes a plurality of closely spaced connection points 38 where the laser beam has fused the two metallic layers of the can jacket 3 and top closure member 56 together.

When merging the can jacket 3 and the upper end part 56 in the overlapping region 53, there are two possibilities. Either the upper end part 56 is analogous to the method illustrated with reference to FIGS. 5a, 5b and 5c brought from Doseninnem in the overlapping region 53 on the can jacket 3 in contact (left side), the contact pressure must be achieved by an insertion. In order to allow pressing from the inside, the insertion holder must be connected by vacuum or a clamping device with the upper end part 56, because there is no access to the inside of the can at the bottom of the can. The second possibility of merging is that the upper end part 56 is brought into contact with the can sheath 3 in the overlapping area 53 on the can jacket 3 (right side), whereby the two parts to be joined can each be pressed against each other from the outside. In both variants, the can jacket 3 and the upper end part 56 are formed in the overlapping area so that the outer contour corresponds to a desired beverage can shape. According to the embodiment shown on the left, the plastic material required for sealing in the laser connection is formed by an inner coating or inner foil 3b of the can jacket 3, wherein the inner foil 3b or the inner coating lies in the overlapping area between the can jacket 3 and the upper closure part 56 lies. In order that the inner film 3b or the inner coating is tightly connected both to the upper end part 56 and to the can jacket 3 in the overlapping area or in the laser connection, a heat treatment is preferably carried out in the overlapping area. In particular, the inner film 3b or the inner coating in the overlapping region comprises a sealing layer facing the upper closing part 56.

According to the embodiment shown on the right, the plastic material required for sealing in the laser connection is formed by an inner coating 58 or inner film of the upper end part 56, with the inner coating 58 or the inner film lying in the overlapping area between the can jacket 3 and the upper end part 56 , So that the inner coating 58 is tightly connected both to the upper end part 56 and to the can jacket 3 in the overlapping area or in the laser connection, a heat treatment is preferably carried out in the overlapping area. In particular, the inner coating in the overlapping region 53 comprises a sealing layer facing the can jacket 3.

When punctiform introduction of the laser energy, the inner foil 3b or the inner coating 58 goes away from the center of the laser beam and the two metallic layers connect without disturbance via the bolt-shaped solidified melt areas 39. The inner foil 3b or the inner coating 58 form one in the circumferential direction in the overlapping area continuous seal. It goes without saying that the tightness can also be achieved or increased by plastic material connected to the inner film 3b and the inner coating 58 arranged on the inner side of the can and analogously to the embodiments according to FIGS. 1c and 4a.

In order to prevent parts of internal coatings and / or inner foils from exposing the metallic layer of the can jacket 3 or the upper end part 56 inside the can, an end face of one of the two parts connected to one another is to be coated inside the can. Accordingly, on the left side, a radially outer end face 56 c of the upper end part 56 is coated. On the According to the guide on the right side, an end face 3 c is coated at the free end of the can jacket 3.

Claims

claims

A can body (1) having a can jacket (3) closed around a can axis (2) and comprising a metallic layer, and a closure part (13, 33, 56) comprising a metallic layer, wherein in an overlapping region (53) of

Closing part (13, 33, 56) and the can jacket (3) along a connecting line a laser connection between the metallic layers of the can jacket (3) and the end part (13, 33, 56) is formed, characterized in that the laser Connection many interruptions along the connecting line or a variety of narrow areas where the two metallic

Layers are fused together, and a plastic material (3b, 7a, 13d, 15, 54, 58) is arranged in the laser connection, wherein the laser connection, the stability and the plastic material (3b, 7a, 13d, 15, 54, 58) ensure the tightness.

2. can body (1) according to claim 1, characterized in that the areas in which the two metallic layers are fused together, as a narrow limited metallic connection points (38) are formed.

3. can body (1) according to claim 2, characterized in that the connecting points (38) form at least one row along the connecting line, but in particular arranged in a grid-shaped manner.

4. can body (1) according to one of claims 1 to 3, characterized in that the end part (13, 33, 56) is an upper end part (33, 56), in particular with a valve seat (5), but optionally with a Aufreisseinrichtung (57) for a beverage can.

5. can body (1) according to one of claims 1 to 3, characterized in that the end part (13, 33, 56) is a bottom of the can (13).

6. can body (1) according to one of claims 1 to 5, characterized in that the plastic material (3b, 13d, 54, 58) in the form of a coating (54, 58) or film (3b, 13d) at least on the final part ( 13, 33, 56) or at the coat (3) is arranged in the overlapping region and lies between the two connected metallic layers.

7. can body (1) according to one of claims 1 to 6, characterized in that on the inside of the can jacket (3) an inner film (3b) is arranged, wherein the material of the inner film (3b) in the areas where the two metallic layers are fused together, is located between the two metallic layers, is displaced by the punk-shaped introduction of laser energy at the appropriate locations and solidified there melting areas (39) of the two metallic layers are formed.

8. can body (1) according to one of claims 1 to 7, characterized in that the can interior along the entire laser connection plastic material (3b, 7a, 13d, 15, 54, 58) is arranged, which with the end part (13, 33, 56) and with the can jacket (3) is tightly connected.

9. can body (1) according to claim 8, characterized in that the plastic material (15) arranged in the form of a ring or plate on the bottom of the can (13) and radially outside with the can jacket (3) is connected.

10. A method for producing a can body (1) with a closed about a can axis (2) can jacket (3) comprising a metallic layer, and a closure part (13, 33, 56) comprising a metallic layer, wherein in one Overlap region (53) of the end part (13, 33, 56) and the can jacket (3) along a connecting line a laser connection between the metallic layers of the can jacket (3) and the end part (13, 33, 56) is formed, characterized in that the laser connection is formed with many interruptions along the connecting line or with a plurality of narrow areas in which the two metallic layers are fused together, and a plastic material (3b, 7a, 13d, 15, 54, 58 ) in the

Laser connection is arranged, wherein the laser connection, the stability and the plastic material (3b, 7a, 13d, 15, 54, 58) ensure the tightness.

11. A method of manufacturing a can body (1) according to claim 10, character- ised in that the areas in which the two metallic layers mit- are fused together as tightly defined metallic connecting points (38) at least in a row along the connecting line, but in particular raster terförmig, are arranged.

12. A method for producing a can body (1) according to claim 10 or 11, characterized in that the areas in which the two metallic layers are fused together, are formed with a laser scanner device, wherein a laser beam, for example, mirror movements along the connecting line or along the overlapping region (53) guided and alternately radiated or interrupted, so that compounds and

Interruptions arise.

13. Apparatus for producing a can body (1) with a can jacket (3) closed around a can axis and comprising a metallic layer, a closure part (13, 33, 56) comprising a metallic layer, and a laser

A joint formed between the metallic layers of the can jacket (3) and the end part (13, 33, 56) in an overlapping area (53) of the end part (13, 33, 56) and the can jacket (3) along a joint line the apparatus comprises a laser welding device and a holding device for holding the can jacket (3) and the closure part (13, 33, 56), characterized in that the laser welding device comprises a scanner laser device (46) which in the overlap region in a plurality of narrow areas with a scanner laser beam (37), the two metallic layers merges together.

The apparatus for manufacturing a can body (1) according to claim 13, characterized in that the scanner laser device (46) comprises a controller, a laser source providing the scanner laser beam (37) for the desired time periods, and at least two perpendicular rotatable mirrors (47) or reflecting surfaces, wherein the scanner laser beam

(37) from the laser source via the two rotatable mirror (47) or reflecting surfaces to the respective desired location of the overlapping region passes and the holding device holds the can jacket (3) and the end part (13, 33, 56) in a fixed position.