JP5319390B2 - Embossing method and apparatus - Google Patents

Description

  In the present invention, an embossed pattern is applied to the side wall of the body of a metal can that is widely used in containers for various beverages such as beer, sparkling liquor, low-alcohol beverages, green tea, etc. It relates to a method and apparatus for forming.

  2. Description of the Related Art Conventionally, it has been widely practiced to emboss a drawn can, drawn and ironed, stretched aluminum or steel seamless can or similar can body side wall. This is in order to improve the aesthetic appeal of the can to the purchaser by decorating the can body and to increase the willingness to purchase, and not only embossing but also decorating by printing.

  As an apparatus for forming an embossed pattern, an inner mold with a concave portion and an outer mold with a convex portion are used, and the concave portion and the convex portion are engaged with each other by relatively moving the inner mold and the outer mold. An apparatus configured to perform embossing is known, and a method for performing such embossing and a mold therefor are described in Patent Document 1, for example. However, in the method of Patent Document 1, when the embossed pattern is changed, it is necessary to replace both the inner mold and the outer mold that enter the can body, and the mold after the mold change. There is a problem that the alignment is complicated and time is required, and the productivity is lowered.

  On the other hand, a method for embossing by forming an embossed pattern on the surface and sandwiching a can barrel side wall of a metal can between a cylindrical outer mold roll made of a resilient material and a die for the same are disclosed in Patent Document 2 and Patent It is described in Document 3. In these Patent Documents 2 and 3, it is described that it is not necessary to set the outer mold in accordance with the inner unevenness, and the productivity can be improved.

  In addition, as an embossing device for forming longitudinal grooves extending in the axial direction in the can body, a mandrel (inner mold) in which a smaller number of concave longitudinal grooves than the number of longitudinal grooves to be formed on the surface as a finished product is formed. ), One long and flexible elastic rail (outer mold), and a transport mechanism that rolls a mandrel covered with a cylindrical can on the mandrel onto the rail, and the can covered with the mandrel includes: FIG. 9 and FIG. 9 of Patent Document 4 show an apparatus in which a can body is sandwiched between a mandrel and a rail while rolling on the rail, and a side wall portion of the can body is deformed by the rail and the longitudinal groove to form a longitudinal groove. 10.

Japanese Patent Laid-Open No. 04-300038 JP 05-503878 JP 2005-14045 A JP 05-504724

  However, if the inner mold and the outer mold are configured to correspond to each other on a one-to-one basis, the same number of outer molds and inner molds are required, and in order to increase the number of molds and increase the production capacity. As the number of one of the inner and outer molds increases, it is necessary to increase the number of the other, which increases the size of the equipment. In addition, when changing the design of the embossed pattern and producing a large variety of small lots on the same can line, there is a problem that it takes a lot of manpower and labor to change the mold, resulting in a decrease in productivity and an increase in cost.

  Therefore, the inner mold and the outer mold do not have a one-to-one correspondence, and the outer mold with respect to the inner mold in which the embossed recess is formed is, for example, in a rail shape made of a resilient material as described in Patent Document 4. It is conceivable to make the outer mold versatile or divertable. However, when the embossed pattern is applied by sandwiching the can body side wall between the inner mold and the outer mold, any of the processing systems disclosed in Patent Documents 2 and 3 and the processing system disclosed in Patent Document 4 However, when the embossed pattern as shown in FIG. 8 is continuously applied over the entire circumference of the can body side wall, the accuracy of the parts constituting the apparatus (for example, gear backlash and assembly accuracy). Etc.), variation in the outer diameter of the inner mold, variation in the inner diameter of the can body, the difference between the outer diameter of the inner mold and the inner diameter of the can body, or the circumferential length accompanying plastic deformation of the can body side wall during embossing Due to changes, the position of the embossing start part and the end part may be misaligned, and as a result, there is an unembossed part where embossing is not performed between the embossing start part and the end part. Arise or is There is a problem in that with or appear double overlap is embossed pattern does not match the start and end of the embossing would impair the appearance. In addition, since a uniform embossed pattern cannot be obtained over the entire circumference, there is a problem that the axial load in the can axis direction does not act uniformly and the buckling resistance is lowered. In this way, when embossing is performed over the entire circumference, there are still problems to be solved.

  Moreover, in patent document 4, in addition to said problem, there exist the following problems. In other words, in the method of rotating the can body covered with the inner mold together with the inner mold while pressing it against the rail-shaped outer mold, the embossed pattern is applied to the portion near the bottom of the can on the side wall of the can body. Various experiments have revealed that a bead-like press-contact mark due to an outer mold is likely to occur on a near side wall.

  In view of the above-mentioned problems, the present invention does not require a large facility modification just by arranging a resilient outer mold plate, and does not cause an outer mold pressure contact mark on a metal can barrel side wall, and thus has an appearance. It is possible to form an embossed pattern with a uniform depth on the entire circumference of the side wall of the can body, streamline the can body material (reducing can cost by thinning the wall), and produce many kinds of small lots. It is an object of the present invention to provide a method and an embossing apparatus that can be used for embossing with durability and practicality.

  In order to achieve the above object, the invention of claim 1 is arranged by inserting a can body from above into an inner mold having an embossed recess on the outer peripheral surface and fixing the can body to the outside of the can body covered with the inner mold. In the embossing molding method of forming an embossed pattern on the entire circumference of the can body side wall by rolling while pressing the can body side wall of the can body fitted in the inner mold against the outer mold having the elastic body on the surface Then, the elastic body is brought into contact with the side wall of the can body, and then the pressure contact force is gradually increased, and the can body is embossed on the side wall of the can body by rotating the can body one or more times while keeping the can body side wall in pressure contact with the elastic body. An effective molding step of forming the embossed pattern on the entire circumference of the can body by re-applying the pressing force to the molding start region, and a separation step of gradually reducing the pressing force following the effective molding step, In the effective molding process, the pressure contact force is Either one or both of the first and second pressurizing forces when rotating is made weaker than the pressurizing force of the elastic body that acts on a place where the embossing is not performed repeatedly. The embossing method characterized by the above.

  Furthermore, the invention of claim 2 comprises an inner mold having a smaller diameter than the cylindrical can body inner diameter of the can body and having an embossed recess in the outer peripheral portion, and an outer mold fixedly disposed on the outer peripheral side of the inner mold. And a can body of a can body that is connected to each other through a gear so that the inner mold rotates when the inner mold and the outer mold move relative to each other, and is inserted into the inner mold. In the embossing apparatus configured to emboss the can body side wall by rotating the can body together with the inner mold by relatively moving the inner mold and the outer mold while pressing against the outer mold, the outer mold is A pressure contact force adjusting means having a belt-like elastic body supported by a plurality of pressing members divided in the direction in which the can body is relatively moved, and configured to be capable of advancing and retracting the pressing members with respect to the inner mold. Between the pressing member and the fixing member for fixing the outer mold Provided, dividing plane of the pressing member, and is characterized in that it is formed in the boundary between the portion where the pressing force is allowed to act place and once that is caused to act twice for embossing.

  According to a third aspect of the present invention, in the second aspect of the present invention, the pressing member of the outer mold is at least 1. from the contact point between the upper shoulder portion of the inner mold and the trunk portion with respect to the inner mold. The embossing apparatus is provided with an inclined portion having a relief angle of 5 ° to 10 ° so that the pressing force of the rubber material is weakened from a lower position of 5 mm upward.

  According to the embossing method of the present invention, the start and end portions of embossing are overlapped. And at the overlapping part, the so-called “twice” part, the first press-contact force that acts when embossing is started and the second part that acts to re-emboss the part that has already been embossed. By making either one or both of the press contact forces weaker than the press contact force of the portion that is not hit twice, it is possible to avoid variations in the emboss depth. Uniformity can be achieved over the entire circumference, and even when the side wall is thin, the buckling resistance against the same load in the axial direction is improved, and rationalization of the can body material is advantageous (can cost reduction). In addition, it is possible to make the misalignment of the double punching portion associated with the change in the circumference at the joint between the embossed pattern formed first time and the embossed pattern formed second time inconspicuous, and improve the appearance of the can. be able to.

  Further, when embossing the can barrel side wall, the surface of the elastic body is crushed by the pressure contact force, and a large distortion is generated in front of the surface, so that the inner mold is generated while generating a so-called bulge called a “bulge”. Although it revolves, it has a separation process that gradually reduces the pressure contact force during embossing, so it is possible to prevent the bulge pressure from concentrating on the end part of embossing. Troubles due to peeling from the member can be prevented.

  In addition, the embossing depth is locally deeper at the edge of the elastic body in order to gently reduce the outer mold presser as described above, rather than the configuration where the molding ends suddenly at the end of the embossing. In addition, the appearance of the can body with the embossed pattern can be improved, and the possibility of impairing the appearance can be avoided.

  Further, according to the embossing molding apparatus of the present invention, the molding tool as the outer mold has a belt-like elastic body supported by a plurality of pressing members divided in the direction in which the can body moves relative to the surface. As a result, when changing the embossed pattern, only the inner mold needs to be replaced, and complicated positioning work is not required, so that the mold can be easily changed in a short time. As a result, productivity is improved and it is advantageous for production of a large variety and a small lot. Moreover, when adjusting the press-contact force of the location hit twice, it can adjust easily by using each divided | segmented pressing member.

1 is a schematic side view of an embossing apparatus according to the present invention. It is the schematic which shows the conveyance path | route of the can in an embossing molding apparatus. It is a top view which shows an embossing part (outer mold | type). It is a vertical side view which shows an embossing part (outer mold | type). It is an expanded sectional view of a pressing member. It is a vertical side view which shows the state which is pressing the side wall of a can against an outer mold | type. It is a graph which shows the amount of escape of a can body circumference and rubber material of the present invention. It is a front view which shows the two-piece can in which the embossing pattern shape | molded by the embossing shaping | molding apparatus of this invention was given. It is a graph which compares and shows the emboss depth in the case where the press-contact force in the embossing shaping | molding method is not adjusted, and the case where it adjusts of this invention.

  Next, the present invention will be described more specifically. The present invention relates to a method for performing embossing by rotating a workpiece to be embossed while moving it along the outer mold in a state of being pressed against the outer mold, and an apparatus configured to perform the method. The apparatus is characterized by its outer mold and an inner mold that rotates while pressing a workpiece against the outer mold. First, an apparatus for rotating a workpiece to be pressed against an outer mold by an inner mold will be described.

  FIG. 1 shows the overall configuration of the apparatus, and an embossing forming apparatus 1 shown here forms a screw part after reducing the diameter of a bottom part of a two-piece can, a three-piece can, or a two-piece can. It is configured to be embossed for a bottle-shaped can or the like for capping a lid. Moreover, the example shown here is applicable also when embossing according to the printing design given to the outer surface side of the can body in the middle of manufacturing processes, such as a three-piece can. Hereinafter, description will be given by taking as an example a can in the middle of production (for example, a cylindrical can for a two-piece can) 2 in which a printing design is applied to the outer surface of the can body. First, the can 2 is continuously fed into the outer edge of the main turret 4 through the infeed turret 3 at equal intervals along the circumferential direction. As shown in FIG. An embossed part (outside) placed close to the transport path after aligning the print design of the randomly supplied can 2 in the alignment adjustment range while transporting continuously at intervals. In the mold 5, the can body of the can 2 is embossed in accordance with the printing design, and then continuously sent out to the subsequent process by the discharge turret 6.

  As shown in FIG. 1, a main shaft 8 supporting the main turret 4 is erected on the base 7 in a rotatable state. A rotation center portion of the main turret 4 is integrally attached to an intermediate portion of the main shaft 8, and the main turret 4 is configured to rotate with the main shaft 8 as a rotation drive shaft. A plurality of mandrels 9 are rotatably supported on the outer edge of the main turret 4 with the central axis thereof directed in the vertical direction and with a certain interval in the circumferential direction.

  On these mandrels 9, an embossing inner mold 9 a is integrally mounted on the upper part of the main turret 4 that protrudes from the upper surface side. A gear portion 9 b is integrally formed at a lower portion of the main turret 4 that protrudes from the lower surface side, and each gear portion 9 b has one large diameter corresponding to the movement trajectory of the mandrel 9 due to the rotation of the main turret 4. Is meshed with the inner gear 10. The inner gear 10 is attached to the upper surface of the base 7.

  Further, an upper chuck 11 for adsorbing and holding the can 2 is provided above each mandrel 9 in the axial direction. Further, a spinning chuck 12 for rotating the can 2 is rotatably inserted so as to surround the mandrel 9 below the inner mold 9a. An AC servo motor 13 for rotating the spinning chuck 12 via a gear is attached to the main turret 4 on the inner side of the mandrel 9. On the other hand, an LED light emitting type color mark sensor 14 for detecting a mark provided on the outer surface of the can body is disposed above the spinning chuck 12 and in the vicinity of the lowermost end portion of the inner mold 9 a of the mandrel 9.

  Above the main turret 4, an upper frame 15 that is fixedly erected from the base 7 is installed in a state where the main shaft 8 is rotatably penetrated through the central portion thereof. Inside the peripheral wall of the upper frame 15, a control box 16 for controlling the rotational drive of the AC servo motor 13 based on the detection result of the color mark sensor 14 is integrated with the main shaft 8 via a vibration-proof rubber 17. Is installed. Further, a slip ring 17 for connecting the control box 16 on the rotation side (main shaft 8) and the power source on the fixed side is attached to the upper end portion of the main shaft 8 in the central space of the control box 16. ing.

  An upper chuck slide cam 18 for moving the above-described upper chuck 11 up and down is attached to the outer peripheral surface of the upper frame 15. Each upper chuck 11 provided for each mandrel 9 is supported by a respective upper chuck slide holder 19 so as to be rotatable in the horizontal direction. Each of the upper chuck slide holders 19 is fitted in a guide rod 20 erected on the main turret 4 in the vicinity of the mandrel 9 so as to be movable up and down. A roller 19 a provided in each upper chuck slide holder 19 is engaged with a cam groove 18 a of the upper chuck slide cam 18.

  Therefore, when the main turret 4 rotates, the mandrel 9 provided at the outer edge of the main turret 4 turns around the main shaft 8. In that case, since the lower gear portion 9b of the mandrel 9 meshes with the inner gear 10 mounted on the base 7, the mandrel 9 moves in the circumferential direction by the rotation of the main turret 4 and moves to the main Rotates synchronously with the turret 4. Each can that has been continuously conveyed by the conveyor from the previous process (can body in the process of being printed with a printed design on the outer surface of the can body) 2 is placed in a state where the printing design of the can body remains in a random state. It is fed through a feed turret 3 above a mandrel 9 rotating with the main turret 4.

  That is, at the delivery position where the infeed turret 3 and the main turret 4 overlap each other, the can 2 is adsorbed by the upper chuck 11 located above the can 2. In this state, when the upper chuck 11 is lowered, the can 2 is slid downward, and is inserted into the mandrel 9 located below the upper chuck 11 from above.

  The vertical movement of the upper chuck 11 is performed by the roller 19a moving in the cam groove 18a of the upper chuck slide cam 18 described above. That is, when the upper chuck slide holder 19 rotates together with the main turret 4 on the outer peripheral side of the upper chuck slide cam 18 fixed to the upper frame 15, the roller 19a attached to the upper chuck slide holder 19 moves to the cam groove 18a. Since the vehicle travels inside, the roller 19a and the upper chuck slide holder 19 to which the roller 19a is attached follow the shape of the cam groove 18a and move up and down while rotating.

  The can 2 fitted into the inner mold 9a of the mandrel 9 from above is sandwiched between the upper chuck 11 and the spinning chuck 12, and is held so as to surround the inner mold 9a with a slight gap. By rotating the AC servo motor 13 in this state, the spinning chuck 12 that is linked to the AC servo motor 13 via a gear rotates. Since the spinning chuck 12 can rotate relative to the mandrel 9 and the inner die 9a integrated therewith, the can 2 can rotate the spinning chuck 12 regardless of the rotation of the mandrel 9 (inner die 9a). It can be rotated with it.

  The can 2 being rotated by the spinning chuck 12 moves in the circumferential direction by the rotation of the main turret 4. In the process of movement, that is, in the conveyance path from the above-mentioned delivery position to the embossed portion (outer mold) 5, the positioning mark applied to the can body is detected by the color mark sensor 14, and the detection result is The rotation of the AC servo motor 13 is stopped by a command from the control box 16 based on the control box 16. By stopping and fixing the spinning chuck 12 in this way, the printing design of the can body is aligned.

  The can 2 that has completed the alignment of the printing design of the can body is fed into the embossing section 5 while being servo-locked. As a result, the can body of the can 2 is sandwiched between the inner mold 9a integrated with the mandrel 9 and the outer mold 5 which is an embossed portion arranged in the form of a rail on the outer periphery thereof. When the can 2 is rotated in accordance with the outer mold 5 along with the rotation, the embossing is performed in accordance with the printing design position of the can body. Then, at the end of the embossing process (at the end of the embossing range), the servo lock of the AC servo motor 13 is released and the spinning chuck 12 is free to rotate.

  In the can 2 thus embossed on the can body, the upper chuck 11 that adsorbs the can 2 at the transfer position where the discharge turret 6 and the main turret 4 overlap each other has an upper chuck slide cam. By being guided by 18 cam grooves 18a and ascending, it is slid upward and pulled upward from the mandrel 9, and then delivered to the discharge turret 6 and sent to the subsequent process.

  The inner mold 9a used in the embossing molding apparatus 1 described above has a recess for imparting a pattern to the side wall of the can 2 on the outer peripheral surface. For example, as shown in FIG. It is formed continuously.

  In addition, the can body side wall is made of an elastic material so that embossed unformed parts due to circumferential deviation due to parts accuracy, gear portion backlash, inner mold outer diameter variation, can barrel inner diameter variation, etc. do not occur. It has a configuration in which the emboss molding start portion is re-molded by rotating it one or more times with pressure contact. As a result, an embossed pattern having no unembossed portion can be formed. It should be noted that the embossing start portion is easily slippery and unstable because the side wall is sandwiched by an outer mold (described later) having a smooth rubber material on the surface. For this reason, it is preferable to perform embossing by rotating at least a place where the embossed pattern overlaps by one pitch.

  Accordingly, the pressing force acts again on the emboss molding start region at the end of the emboss molding, and the emboss molding is performed overlapping this portion (region). However, when embossing is performed repeatedly with the same pressure contact, the embossing depth of the part where the overlapping embossing is performed becomes deeper than the other parts, in addition to the appearance problem associated with the circumferential deviation. It became clear from real life. Even if this difference in emboss depth is small, if the can body wall thickness is thin, it will be easy to buckle due to stress concentration when an axial load is applied in the subsequent neck-in or winding process. Therefore, it becomes an obstacle to rationalization of the can body material, that is, an obstacle to material thinning. Therefore, in the present invention, among the press contact forces to be applied for the overlapping embossing as described above, either the first press contact force or the second press contact force or both of the elastic bodies are used. The pressure contact force of the elastic body is weaker than the pressure contact force of the elastic body acting on the portion where the embossing is not performed repeatedly. As a result, the appearance is improved and the embossing with a uniform depth is provided over the entire circumference of the can body side wall. It is comprised so that a pattern may be formed.

  Furthermore, damage to the elastic body can be reduced by adopting a structure having a separation step of gradually reducing the pressure contact force following the effective forming step.

  More specifically, in the apparatus of the present invention, the outer mold 5 has a special structure. FIG. 3 is a cross-sectional plan view of the outer mold 5, and FIG. 4 is a longitudinal side view of the outer mold 5, and the swiveling of the outer side of the can 2 swiveling as the main turret 4 rotates is turned. A base plate (fixing member) 21 is disposed along the locus. A pressing member 22 is attached to the front surface of the base plate 21, that is, the surface of the can 2 on the turning locus side. The pressing member 22 is a plate-shaped member having a substantially central portion in the turning direction of the can 2 that is recessed in an arc shape, and both sides thereof being formed in a substantially flat shape, and has a certain degree of rigidity, and a portion that is recessed in the arc shape. Is substantially the same as the turning radius of the outer peripheral surface of the inner die 9a. Further, the pressing member 22 is divided into a plurality (two in the example shown in the figure) in the turning direction of the can 2, and the divided pieces 22 a and 22 b are individually bolted to the base plate 21. Each of the divided pieces 22a and 22b is configured to be movable back and forth with respect to the inner mold 9a in order to adjust the pressing force applied to the side wall of the can 2. That is, pressure contact force adjusting means is provided, which is a shim 23 interposed between the base plate 21 and the divided piece 22a in the example shown in the figure. By adjusting the thickness of the shim 23, the distance between the inner mold 9a and the pressing member 22a is adjusted. Along with this, the pressing force that acts on the can 2 for the first time, that is, the pressing force is the reference pressing force by the pressing member 22a. It is comprised so that it can adjust to.

  In this way, the pressing member 22 is constituted by the divided pieces 22a and 22b. By rotating the can 2 one or more times, the molding process force is again applied to the emboss molding start portion at the end stage of the emboss molding. As part of the embossing process is performed with some overlap, a part where the embossing is performed only once and a part where the embossing is performed twice are generated. Therefore, the boundary position of each of the divided pieces 22a and 22b, that is, the divided surface, is the portion where the can 2 is re-embossed after the can 2 is rotated once and the embossing is performed only once. It is set so as to correspond to a boundary portion with a portion not applied.

  Further, the front surface of the pressing member 22 is not flat in the entire vertical direction (the axial direction of the can 2), and at least the upper end portion is inclined in the backward direction as shown in FIG. In the example shown in FIG. 5, inclined portions 24a and 24b are formed at both upper and lower ends. The inclined portion 24a is for avoiding the formation of a bead-shaped molding mark on the can barrel side wall on the bottom side of the can 2, and the upper end portion M (the shoulder portion and the trunk portion between the shoulder portion and the trunk portion) of the inner mold 9a. A position that is lower than the L dimension (1.5 mm or more) from the contact point), that is, a position that is close to the center of the can 2 in the axial direction, is formed as a surface that is retreated in the range of W1 with a relief angle θ1 of 5 ° to 10 °. It is preferable to do this. The lower limit position of the starting point K of the inclined portion 24a is not limited as long as the rubber material 25 is pushed into the embossed recess of the inner mold 9a. In addition, the inclined surface 24b on the lower end side is formed as a surface that recedes from the embossed recess lower limit position within a predetermined dimension W2 and within a range where the escape angle θ2 is less than 35 °. This may be a material that can clamp the lower end of the rubber material and does not cause poor adhesion due to bending in the rubber material 25.

  As shown in FIG. 6, a rubber member 25 is attached to the front surface of the pressing member 22 so as to cover the whole. The attachment is mainly performed by adhesion, but as described above, the upper and lower ends of the rubber member 25 are hooked on the inclined surfaces 24a and 24b in order to ensure that they are in close contact with the inclined surfaces 24a and 24b. Clamp members 26 to be pressed are attached to the upper and lower ends of the pressing member 22.

  The configuration of the rubber material 25 will be further described. The rubber material 25 has a laminated structure of a surface layer, which is a rubber layer, and a lower layer composed of a sponge layer and a plurality of cloth layers. For example, model number T567W manufactured by Kinyo Co., Ltd. or air tack F is used. The rubber material provided with the sponge layer can absorb the shock when the can 2 is embossed while rotating while moving on the front side of the outer mold 5 and can function to adjust the emboss depth. Thus, it has a structure in which bubbles are contained. Sponge structures can be broadly classified into sponges having a single-cell structure in which bubbles are arranged independently and sponges having an open-cell structure in which bubbles are connected to each other. When the sponge layer has an open cell layer structure, in the emboss molding that requires a strong pressure contact force, the stress is concentrated at the end of the molding where the can 2 rolls on the outer mold 5 and is embossed. Since the influence is increased and the delamination of the rubber material 25 is likely to occur, and the durability is lowered. Therefore, when importance is attached to the durability, it is preferable to provide a sponge layer having a single cell structure.

  The thickness of the rubber member 25 is appropriately selected depending on the embossed shape and depth, the size thereof, the material of the can body and the wall thickness.

  The surface roughness of the rubber material 25 is Ra 0.6 to 0.8, and the hardness of the rubber material 25 is 80 ± 10 as the Shore hardness specified in JISK6253, although it depends on the emboss depth. Butadiene rubber is used. If the hardness of the rubber material 25 becomes too small, the embossed pattern does not appear sharply, and the embossed portion is blurred and the action of attracting attention tends to be weakened. On the contrary, if the hardness of the rubber material 25 becomes too large, a large pressure contact force is required, and the apparatus must be made to have a rigid structure, which increases equipment costs. In addition, it becomes difficult to mold a deep embossed depth.

  The band-shaped rubber material 25 is formed by pressing the rubber member 25 into the recess of the inner mold 9a to the approach area L1 where the pressure contact force gradually increases and to the length exceeding the circumference of one can following the approach area L1. A region L2 and a separation region L3 where the pressure contact force gradually decreases are provided.

  As shown in FIG. 7, the molding region L2 is a range (PS section) in which at least the can 2 is rotated one or more times in a state where the pressure contact force for sandwiching the can 2 is adjusted. Further, the approach region L1 is a region provided on the upstream side of the molding region L2, and is a region that alleviates the collision so that the can 2 and the rubber material 25 abruptly contact each other and a rubber mark is not formed. . Further, the separation region L3 is a region provided on the downstream side of the molding region L2. When the can 2 and the rubber material 25 are abruptly separated from each other, stress tends to concentrate on the edge of the rubber material 25, and the rubber itself is damaged. (E.g., sasakure) occurs. In order to avoid this, it is an area provided for the purpose of stress distribution so as not to concentrate the stress generated at the end of the rubber member 25.

  In the approach area L1, when the can 2 is fitted into the inner mold 9a and revolves around the front side of the outer mold 5, the pressure contact force for embossing gradually increases, and the subsequent molding area L2 Then, the side wall of the can body is firmly sandwiched between the rubber material 25 and the inner mold 9a, and the substantial embossing is performed. When biting in, so-called rubber marks are easily formed. Therefore, in order to avoid such inconvenience, the approach region L1 is provided to gradually increase the pressure contact force.

  As described above, the inclined surfaces 24a and 24b are formed on the front surface of the pressing member 22 to which the rubber member 25 is attached, and a portion between these inclined surfaces 24a and 24b is a pressure contact surface portion 24c. . The pressure contact surface portion 24c corresponds to the width corresponding to the molding surface with the concave pattern of the inner mold 9a, and the position lower than the contact point M between the body portion and the shoulder portion of the inner mold 9a is set as the upper limit position. The rubber member 25 is pressed against the side wall of the can 2. In particular, when the embossed pattern is formed near the bottom of the can, if a relief of dimension W1 is not provided at the upper end portion of the pressing member 22, a bead-shaped molding mark is formed on the can barrel side wall on the can bottom side, and the molding trace is also formed. The depth of the can also change in the vicinity of the overlapping region, so the appearance of the can is impaired. The reason why such a bead-shaped molding mark occurs is that the wall thickness of the can barrel side wall portion on the bottom side of the can is thicker than the central portion of the barrel portion, so that the embossed pattern is to be formed close to the contact point M. The embossed pattern does not appear sharp unless a pressure contact force stronger than that of the central portion where the wall thickness is thin is applied. Therefore, it is considered that when a large pressure contact force is applied to the can barrel side wall, the side wall is pushed in along the radius of curvature r of the inner shoulder. Therefore, in the present invention, when the embossed pattern is provided near the bottom of the can, it is necessary to devise such as providing a relief with a predetermined dimension W1 in the pressing member in order to avoid such a problem. In this sense, the pressing member 22 of the outer die 5 is pressed against the inner die 9a by a pressure force of the rubber member 25 from the lower end of the inner die 9a to the upper portion from the contact point between the upper shoulder portion and the trunk portion at least 1.5mm upward. An inclined portion having a relief angle of 5 ° to 10 ° is provided so as to be weakened.

  As described above, the pressing member 22 is constituted by two divided pieces 22a and 22b, and a shim 23 is inserted between the one divided piece 22a and the base plate 21, so that the space between the divided pieces 22a and 22b. There is a step on the split surface. However, since the entire front surface of the pressing member 22 is covered with the rubber material 25, the step is a surface that is smoothly continuous with the rubber material 25. Therefore, the approach region L1 and the molding region L2 described above are the same. It is in a connected state with a smooth curved surface. In FIG. 7, the rubber escape amount is shown to change stepwise, but this is because it is schematically shown.

  Next, the operation of the embossing apparatus described above, that is, the embossing method of the present invention will be described. As described above, the can 2 to be embossed is fed between the inner mold 9a and the upper chuck 11 pulled upward by the infeed turret 3, and the upper chuck 11 adsorbs the bottom of the can. The upper chuck 11 is lowered together with the upper chuck slide holder 19 by the action of the upper chuck slide cam 18 by the action of the upper chuck turret 3, whereby the can 2 is fitted into the inner mold 9 a from above, and the upper chuck 11 and the spinning chuck 12.

  Since the mandrel 9 integrally provided with the inner mold 9 a is held by the main turret 4, the main turret 4 is rotated so that the inner mold 9 a and the can 2 fitted therein are centered on the main shaft 8. Turn around the circle. In this process, the position of the print design is detected, and the AC servo motor 13 is controlled based on the detection result, and the can 2 is rotated so as to align the print design. Note that the printing design alignment function is the same as that described in JP-A-2001-47165.

  When the can 2 further swivels together with the inner mold 9a or the mandrel 9 and reaches the embossed portion 5, first, the side wall of the can 2 comes into contact with the rubber material 25 in the approach region L1 described above. At this time, since the clearance is provided between the outer peripheral surface of the inner mold 9a and the inner peripheral surface of the can 2, no pressure contact force acts positively on the side wall of the can 2, and the center of the inner mold 9a The can 2 is moved so that the axis of the can 2 is eccentric with respect to the shaft. This step corresponds to the approach step in the present invention.

  In this approaching step, when the can 2 further moves on the front side of the outer mold 5, the surface of the rubber material 25 and the inner mold 9 a gradually approach each other, and finally the side wall of the can 2 is connected to the rubber material 25 and the inner mold 9 a. It is sandwiched between. The pressure contact force acting on the side wall of the can 2 gradually increases. This is the process from point O to point P in FIG. Thus, embossing is substantially started on the side wall of the can 2.

  And the can 2 moves to the shaping | molding area | region L2 from the approach area | region L1. The former part of the molding region L2 is an area corresponding to one of the divided pieces 22a whose position is adjusted by the shim 23. The rubber material 25 in the former part of the region L2 is in relation to the latter part of the region L2. Relatively slightly receding. That is, the pressure contact force acting on the can 2 is relatively small. This is the process from point P to point Q in FIG.

  The can 2 inserted into the inner mold 9a is rotated together with the inner mold 9a because the gear 9b integrated with the inner mold 9a meshes with the inner gear 10 and rotates together with the main turret 4. Rotate. That is, the can 2 moves on the rubber member 25 pressed against the front surface of the rubber member 25 and rotates, and moves while rolling on the front surface of the rubber member 25. In this way, the embossing progresses and reaches the boundary portion of each of the divided pieces 22a and 22b described above. Even if there is a step at the boundary portion of each divided piece 22a, 22b itself, this boundary portion is also covered with the rubber material 25 and is a smoothly continuous curved surface, so that the embossing is continued without hindrance. The subsequent pressing force is maintained constant by the curvature radius of the surface of the rubber member 25 substantially matching the turning radius of the outer peripheral surface of the can 2. This is a process from the point Q to the point R in FIG.

  In the latter part of the molding region L2, the rubber material 25 is pushed into the concave portion of the inner mold 9a with a constant pressure in this way, and embossing proceeds. The pressure contact force is relatively larger than the front portion of the molding region L2 because the divided piece 22a is moved away from the turning trajectory of the can 2 by the shim 23. Then, at the final stage of the molding region L2, the embossing is performed again by applying the pressing force to the portion where the pressing force has already been applied at the start of the embossing molding. Strike twice. This is the process from point R to point S in FIG. In that case, the pressure contact force at the preceding stage portion against the portion hit twice is held while the one divided piece 22a in the portion is moved backward relative to the divided piece 22b and is not hit twice. Embossing is performed in a state where it is lower than the pressure contact force against the side wall of the can 2. Therefore, in the portion where embossing is performed again by applying the pressure contact force in the subsequent stage portion, the material of the can 2 does not stretch greatly, so that the embossed depth does not increase only in the overlappingly formed region. As a result, it is possible to prevent a situation in which the embossing depth becomes uneven as a whole. In other words, the embossing depth can be made uniform even at a so-called double hit location. The embossing process in the approach area L1 and the molding area L2 corresponds to the effective molding process in the present invention.

  When the can 2 passes through the molding region L2 and reaches the separation region L3, the press contact surface portion 24c of the outer mold 5 gradually moves away from the turning trajectory of the outer peripheral surface of the can 2, so that the press contact force acting on the side wall of the can 2 is increased. The pressure gradually decreases, and finally, the can 2 moves away from the surface of the rubber member 25 and the pressure contact force does not act. That is, substantial embossing is completed. This is a process from point S to point T in FIG. In this way, at the end stage of embossing, the load applied to the rubber material 25 gradually decreases, so that the pressure force does not suddenly become zero, and the stress of the rubber material 25 that is likely to occur at the final stage of the forming region L2. Concentration can be avoided. The processing in the separation region L3 corresponds to the separation step in the present invention.

  Here, a measurement result when embossing is performed by the method of the present invention and a measurement result of a comparative example in which the pressing force is kept constant throughout the entire process from the start to the end of the process are shown. The target can 2 is a 350 ml can made of an aluminum alloy drawn and ironed with an outer diameter of the can barrel of 66.1 mm and a minimum wall thickness of 0.105 mm. A 3 mm embossed pattern was applied. The external appearance is shown in FIG. 8, the embossed pattern is 4 × 33 plane, and the embossing was performed using an inner mold having a depth of 0.5 mm of the embossed concave part with an overlapping angle of 32.7 °. The measurement result of the emboss depth is shown in FIG. The measurement result for the example of the present invention is indicated by symbol A in FIG. 9, and the emboss depth is approximately 0.3 mm over the entire circumference, confirming that the depth is uniform. On the other hand, the measurement result of the comparative example in which the pressure contact force is maintained uniformly in all processes is indicated by a symbol B in FIG. The embossing depth of the steel became deeper than the target of 0.3 mm, and the deepest part increased by about 26% to about 0.38 mm. The trace of the double strike was strong at the joint and the appearance of the can 2 was damaged. .

  The present invention is not limited to the specific examples described above. That is, in the region where the embossing from the forming start point of the effective forming region of the embossed portion to the can body overlaps (the region hit twice), the pressing force adjusting means that weakens the pressing force of the forming region where the embossing does not overlap In this example, the divided pressing member is moved in the inner mold direction by changing the thickness of the shim so that the pressing force of embossing can be adjusted in a specific region, but the pressing member can be moved. If it is a thing of a structure, a moving direction in particular will not be limited. For example, the radius of curvature of the support surface of the pressing member that adheres and supports the rubber material may be constituted by a plurality of curvature radii, and may be moved so that the curvature radii are different for each region.

  Moreover, in this example, it is in the state weaker than the press-contact force with respect to the perfect shaping | molding area | region (QR section) which does not hit twice the press-contact force of the front | former part (OQ section) of the area | region L2 including the area | region L1 hit twice. However, the present invention is not limited to this, and the pressure of the latter part (R-S section) of the region L2 to be hit twice may be set to be weaker than the pressure not to hit twice. Further, the pressure welding force of both the front stage portion and the rear stage portion may be set to be weaker than the pressure welding force for the portion that is not hit twice, or the pressure welding force of the front stage portion may be further divided and adjusted. That is to say, the embossing shape, depth, width, molding position, molding speed, rubber hardness, can body material, wall thickness, etc. The pressing force is appropriately determined for each region so as to obtain a uniform emboss depth.

  In addition, in this example, an example of a mirror ball type can is shown in which an embossed pattern (4 × 33 surface embossing, depth 0.3 mm) is formed on the entire surface of a can body side wall having a can body outer diameter of 66.1 mm. However, the emboss depth can be molded to about 0.5 mm.

  Further, in this example, the wrap angle corresponding to the region where the embossing is performed overlappingly (the region where the embossed pattern overlaps by one pitch) is set to 32.7 °. However, the present invention is not limited to this, and at least the can The ratio of the inner diameter of the can body and the outer diameter of the inner mold (the number of embossed patterns to be applied and the inner mold) is sufficient as long as the angle is such that the body can be rotated once or more and the pressure contact force is applied again to the embossing start region. The ratio of the number of the embossed recesses).

  DESCRIPTION OF SYMBOLS 1 ... Embossing apparatus, 2 ... Can, 3 ... Infeed turret, 4 ... Main turret, 5 ... Embossing part (outer type), 9 ... Mandrel, 9a ... Inner type, 10 ... Inner gear, 11 ... Upper chuck, DESCRIPTION OF SYMBOLS 21 ... Base plate, 22 ... Pressing member, 22a, 22b ... Divided piece, 23 ... Shim, 24a, 24b ... Inclined part, 24c ... Pressure-contact surface part, 25 ... Rubber material, 26 ... Clamp member, L1 ... Approaching area, L2 ... Molding Region, L3 ... separation region.

Claims (3)

A can body is inserted from above into an inner mold having an embossed recess on the outer peripheral surface, and is fixed to the outside of the can body covered with the inner mold, and an inner mold relative to an outer mold having an elastic body on the surface. In the embossing molding method of forming an embossed pattern on the entire circumference of the can body side wall by rolling while pressing the can body side wall of the can body inserted into,
Embossing of the can body side wall by gradually increasing the pressure contact force after contacting the elastic body with the can body side wall and rotating the can body one or more times while the can body side wall is in pressure contact with the elastic body An effective forming step of forming the embossed pattern on the entire periphery of the can body by re-applying the pressure contact force to the starting region of the step, and a separation step of gradually reducing the pressure contact force following the effective forming step,
In the effective molding step, one or both of the first and second pressurizing forces when the pressurizing force is applied twice are applied to a portion where the embossing is not performed repeatedly. The embossing method characterized by making it weaker than the press-contact force of the said elastic body. An inner mold having a smaller diameter than the inner diameter of the cylindrical can body of the can body and having an embossed recess in the outer peripheral portion, and an outer mold fixed and arranged on the outer peripheral side of the inner mold, and these inner mold and outer mold Are connected to each other via a gear so that the inner mold rotates when the inner mold and the inner mold are rotated, while pressing the can body of the can body fitted and inserted into the inner mold against the outer mold. In the embossing apparatus configured to emboss the can body side wall by rotating the can body together with the inner mold by relatively moving the mold,
The outer mold has on its surface a belt-like elastic body supported by a plurality of pressing members divided in the direction in which the can body moves relatively,
Pressure contact force adjusting means configured to be able to advance and retract each of the pressing members with respect to the inner mold is provided between the pressing member and a fixing member that fixes the outer mold,
2. The embossing apparatus according to claim 1, wherein the dividing surface of the pressing member is formed at a boundary position between a place where a pressing force for embossing is applied twice and a place where the pressing force is applied once.   The pressing member of the outer mold is weakened with respect to the inner mold by at least 1.5 mm from the contact point between the upper end shoulder and the trunk of the inner mold from the lower position to the upper side. The embossing apparatus according to claim 2, further comprising an inclined portion having a relief angle of 5 ° to 10 °.

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