JP3929282B2 - Apparatus and method for producing resin-coated metal seamless can body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, a cup-shaped intermediate material obtained by drawing a metal plate coated on both sides with a thermoplastic resin is subjected to redrawing or redrawing ironing or ironing with a punch and a die. The present invention relates to an apparatus and a manufacturing method for manufacturing a seamless can body with a cap.
[0002]
[Prior art]
In general, metal cans (containers) made of aluminum or steel are roughly classified into three-piece cans, two-piece cans, and bottle-type cans according to their shapes. The three-piece can is called a three-piece can because it consists of a bottom lid, a can body joined by welding or adhesion, and a canopy. In addition, the two-piece can is a structure in which a canopy is attached to a can body in which the bottom of the can is integrated. The two-piece can is referred to as a two-piece can because the can body and the canopy are two constituent members. It is also called a seamless can because it has no seams. Furthermore, the bottle-shaped can is composed of a side seamless can body having a threaded portion formed at one open end of the can body, a cap and a bottom cover screwed to the threaded portion, and the overall shape is glass. It is called a bottle-shaped can because it is close to a bottle made of plastic.
[0003]
In any of these metal cans, a protective layer made of a synthetic resin is formed on the inner surface of the can in order to ensure corrosion resistance. In recent years, a laminated can having a coating made of a thermoplastic resin as a protective layer has been developed and put into practical use. This type of laminated can is made of a resin film-covered metal plate obtained by laminating a resin film on a metal material, and is often formed into a can body by deep drawing or drawing and ironing. In order to obtain a two-piece can body, since the amount of deformation or the degree of processing of the material is large, a high molding technique is required.
[0004]
That is, the merit of the laminate can depends on the organic resin film to be applied, but it is excellent in content resistance, particularly in flavor such as taste and flavor of the contents. On the other hand, as a disadvantage, it is a problem in can manufacturing, but because the processing degree (or forming degree) of the thermoplastic resin film metal plate is large, the inner resin film is scratched during molding, and the quality of the inner surface of the can Therefore, it is necessary to strictly inspect the quality of the can body, and the product yield is inferior to that of a general paint can.
[0005]
In particular, in the case of a two-piece type laminate can made of a steel material, the tendency is great, but the same thing occurs in an aluminum material laminate can. Such a defect of the resin film on the inner surface of the laminated can enters at the time of can molding as described above, and minimizing this defect is an important issue in terms of quality and product yield.
[0006]
As described above, the laminate can is also manufactured by drawing, redrawing and ironing or ironing a cup-shaped intermediate material made of a coated metal plate coated with a thermoplastic resin film. 2. Description of the Related Art Devices that are configured to control the temperature of a forming tool are known as devices that can prevent fractures and cracks in coating resin. This type of apparatus is described in, for example, Japanese Patent Application Laid-Open No. 1-278921, Japanese Patent Application Laid-Open No. 6-210381, and Japanese Patent Application Laid-Open No. 7-275961.
[0007]
To briefly explain the invention described in these publications, the method described in JP-A-1-278921 is a method for producing a container in which the temperature of the punch during the process is maintained at a temperature of 50 ° C. to 80 ° C. In the method described in JP-A-6-210381, when a seamless can is manufactured by redrawing from a laminated metal plate in which polyester films are laminated on both sides, the inside of the die (or in the die and the wrinkle presser) is used. The hot water was allowed to flow through and was switched to cold water just before the start of processing, so that the surface temperature of the die facing the wrinkle presser (or the wrinkle presser facing the die) was maintained at 40 to 100 ° C. during the processing. In addition, the invention described in Japanese Patent Application Laid-Open No. 7-275961 heats the inside of the die, the wrinkle presser and the punch before the molding operation, and cools the heating immediately before the molding starts. Toggles, continued cooling during molding, a method for producing a seamless can which is to maintain the die during molding, wrinkles retainer and punch of the surface temperature, and extracted punch surface temperature immediately after within a predetermined temperature range.
[0008]
[Problems to be solved by the invention]
In the invention described in each of the above publications, the temperature of the die and punch or the wrinkle presser is maintained within a predetermined range before or after the molding process is started and during the molding process. The punch and wrinkle presser are heated before the molding process and cooled just before the molding process starts. In this way, the thermal expansion amount of the die and punch can be made almost equal, and the clearance between them can be kept almost constant, and the resin film can be slipped and stretched well to prevent cracks and other defects to some extent. Can do.
[0009]
However, when the change in temperature from the start of forming the punch and the die when the redrawing or redrawing ironing or ironing of the laminated metal sheet was actually performed, the temperature rise of the punch was remarkable. As a result, it was observed that the temperature rise of the die was slower than that of the punch. This is because the die has a small contact area with the workpiece, that is, the cup-shaped intermediate material, and one punch has a large overall contact area with respect to the heat generating portion and a small heat capacity as a whole. It seems to be caused by. Therefore, as in the conventional invention described above, if the die is cooled in the same manner as the punch, the difference between the thermal expansion amounts of both is increased, and as a result, the clearance between the die and the punch is reduced, and the can body The wall thickness is not stable, which may cause molding defects such as fraying of the can body at the start of molding, torn cylinder or uneven thickness, variation in molding dimensions, or cracks in the resin coating. .
[0010]
The present invention has been made paying attention to the above technical problem, and provides an apparatus and a method capable of producing a seamless can body without optimizing the temperature of a die and causing a molding defect. It is the purpose.
[0011]
[Means for Solving the Problem and Action]
In order to achieve the above-mentioned object, the invention of claim 1 is characterized in that a cup-shaped intermediate material obtained by drawing a resin-coated metal plate in which both surfaces of the metal plate are coated with a thermoplastic resin is redrawn by a punch and a die. drawing or re-drawing and ironing or ironing to you molded into a bottomed can barrel with a flange, in the manufacturing apparatus of the tree butter coated metal seamless can barrel having a heating and cooling means for heating and cooling the die, the A flow path is formed inside the die, and a high-temperature heat source section that supplies a high-temperature fluid at a temperature higher than normal temperature and a low-temperature heat source section that supplies a low-temperature fluid at a temperature lower than normal temperature are connected to the flow path. A switching valve that selectively supplies a low-temperature fluid and a high-temperature fluid to the die, and a high-temperature fluid is supplied to the inside of the die by switching from a low-temperature fluid to a high-temperature fluid immediately before or at the start of molding. And a die temperature adjusting means for increasing the temperature of the die, and the die was loosely inserted into the die holder so that the die that was heated and expanded along the entering punch could be automatically aligned. The manufacturing apparatus is characterized by being held in a state .
[0012]
The invention of claim 2 is to redraw or redraw a cup-shaped intermediate material formed by drawing a resin-coated metal plate whose both surfaces are coated with a thermoplastic resin by a punch and a die. Alternatively, in a method of manufacturing a resin-coated metal seamless can barrel that is ironed and formed into a bottomed can barrel with a flange, the die is heated by supplying a low-temperature fluid at room temperature or lower to the inside of the die before the molding process. Without changing the low-temperature fluid to the high-temperature fluid immediately before or simultaneously with the start of the molding process, the die is heated and expanded in accordance with the temperature rise of the punch, It is a manufacturing method characterized by maintaining the clearance between them appropriately .
[0013]
In the manufacturing apparatus or manufacturing method of the present invention is therefore, before carrying out the molding using the punch and die, or interrupting the molding process, or when being ineffective, dice the heating is not executed. On the other hand, when the forming process using the punch and the die is started, the die is heated . As a result, the temperature of the die is increased in accordance with the temperature increase of the punches due to molding. Since the die is held so as the axis of displacement of heating expanded dice against ingress to come punch is prevented, the clearance maintained between the punch and the die, is the al can body Thus, the resin film provided on the surface of the surface of the resin film is satisfactorily slipped and stretched, and accordingly, molding defects are avoided or suppressed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. First, an example of a seamless can body targeted by the present invention is a can body of a bottle-type can in which a cap is attached to the mouth and neck, and this is manufactured through, for example, the process shown in FIG.
[0015]
As the material of this seamless can body, a resin-coated metal plate laminated with thermoplastic resin on both sides is used, and this is punched into a disk shape in the cup molding process to make a blank, and the blank is drawn into a cup shape. The intermediate material is formed. In the next can body forming step, the cup-shaped intermediate material is redrawn and ironed at least once to form a bottomed cylindrical can body having a small diameter and a thin wall. . In that case, bending and stretching may be performed at the same time.
[0016]
Next, in the top dome forming step, in order to form the can bottom side of the bottomed cylindrical can body into the mouth neck portion and the shoulder portion, first, in the first step, the can bottom corner portion in the above can body (Bottom part and cylindrical part near the bottom part) are molded into a curved surface of the lower part of the shoulder with an arc-shaped longitudinal section, and a small-diameter bottomed cylindrical part is drawn and formed on the bottom side of the can in the second to third steps. On the other hand, the diameter of the bottomed cylindrical portion is reduced until it becomes almost the same as the diameter of the mouth-and-neck portion by performing drawing processing a plurality of times so that the diameter becomes smaller. Further, in the fourth step, the shoulder portion formed following the initial shoulder lower curved surface by repeating such drawing is reshaped (reformed) into a continuous smooth curved surface. In the fifth step and the sixth step, the bottomed cylindrical portion formed to have the same diameter as the mouth and neck portion is subjected to two times of mouth drawing.
[0017]
The lubricant adhering to the can body formed in the top dome forming step with the opening and neck portion and the shoulder portion with the unopened can bottom side removed in the next lubricant removing step. In the subsequent trimming step, the opening end side of the body part opposite to the mouth and neck part is trimmed to make the can a predetermined length. Furthermore, in the printing / painting process, the desired design (letters, decorative patterns, etc.) is printed on the outer surface of the cylindrical body whose end opposite to the mouth / neck is open, and the printing is performed. A transparent curable paint (clear paint) for protecting the outer surface of the can is applied as a top coat to the outer surface of the body. This printing and painting process is the same as the printing and painting process for the cylindrical body of a normal two-piece can.
[0018]
The can body that has been printed and painted is sent to the next drying step to sufficiently dry the printing ink layer and the top coat layer. In this drying step, the laminated thermoplastic resin layer is heated and melted to a temperature equal to or higher than its crystal melting temperature, and then made amorphous by cooling to 160 ° C. within 8 seconds. After that, in the screw / curl molding process, first, the front neck closed portion of the unopened mouth / neck portion is trimmed to open the mouth / neck portion, and the open end portion is externally wound (or internally wound) to form an annular curled portion. Then, a screw for screwing a cap is formed on the cylindrical peripheral wall, and then a bead portion is formed below the screw forming portion.
[0019]
In the neck / flange forming step, one or more neck-in processes and flange processes are sequentially performed on the lower end opening end of the body part opposite to the mouth / neck part. The bottle-shaped can body thus obtained is sent to a bottom lid tightening step (not shown), and a bottom cover of another member made of a metal plate is attached to the bottom end opening of the body portion by a seamer (can lid tightening machine). The bottle-shaped can is completed by being integrally fixed to the flange portion formed by the double winding method.
[0020]
Here, the resin-coated metal plate that can be used in the present invention will be described. The metal plate to be resin-coated is not particularly limited, and an aluminum alloy plate or various surface treatments such as metal plating and chemical conversion treatment are performed. Surface-treated steel sheets such as ultrathin tin-plated steel sheets, nickel-plated steel sheets, electrolytic chromic acid-treated steel sheets, and galvanized steel sheets can be used. As the surface treatment, it is desirable to use a surface-treated metal plate for the purpose of ensuring adhesion with the thermoplastic polyester resin film.
[0021]
For example, chromic acid chromic acid treatment or zirconium phosphate treatment, which is used as a surface treatment after molding of ordinary drawn iron cans, is applied. In the case of a processing degree, an organic-inorganic composite chemical conversion treatment of phosphoric acid or zirconium phosphate and an organic resin is effective. Specifically, for example, an aluminum alloy plate having a thickness of 0.24 mm to 0.38 mm, and 3004 series or 3104 series aluminum alloy specified in Japanese Industrial Standards (JIS), 1 to 40 mg / m ^{2 of} chromium. , Treatment with adhering phosphoric acid chromate, or zirconium 4 to 17 mg / m ² In addition, a material subjected to a chemical conversion treatment such as an attached zirconium phosphate treatment is used.
[0022]
Moreover, the steel plate in the present invention is a surface-treated steel plate having a thickness of 0.15 mm to 0.25 mm, for example, and the adhesion amount on one side of the steel plate is 20 to 2000 mg / m ^2. Nickel plating layer, those having a chemical conversion coating layer composed mainly of an organic resin of 100 mg / m ² from the 1 mg / m ² as a single-side adhesion amount of C is used as an upper layer. In addition, the steel plate before nickel plating and chemical conversion treatment is not specifically limited, What is normally used as a steel plate for cans is applied.
[0023]
As the resin film coated on the metal plate, a thermoplastic polyester resin film having good heat resistance and characteristics suitable for can applications is used. Examples of the polyester resin include polyethylene terephthalate (PET) and polybutylene. Homopolymers such as terephthalate (PBT) and polyethylene isophthalate (PEI), copolymers such as copolymers of polyethylene terephthalate and polyethylene isophthalate, blends of such homopolymers, homopolymers and copolymers, etc. Examples thereof include blends and blend resins of copolymers. Lamination of a resin film to a metal plate is performed by a heat fusion method, a dry lamination method, an extrusion coating method, or the like. If the adhesiveness with the coating resin is poor, for example, a urethane adhesive, an epoxy adhesive, an acid An olefin adhesive, a copolyamide adhesive, and a copolyester adhesive can be interposed.
[0024]
Furthermore, the melting point of the thermoplastic polyester resin used in the present invention can be appropriately selected depending on the degree of the copolymer, the selection of the resin to be blended, and the blend ratio thereof. For example, the melting point (Tm) is 200 ° C. to 260 ° C. The resin film is applied. In addition, the resin-coated metal plate of the present invention is made amorphous after being laminated, after being heated and melted above the melting point of the thermoplastic resin film that has been thermally bonded, and then rapidly cooled below the glass transition point. A resin-coated metal plate in which biaxially oriented crystals remain on the upper layer side of the thermoplastic resin coating layer may be used.
[0025]
The apparatus and method of the present invention can be used in the can body forming process among the processes from the cup forming process to the neck and flange forming process described above. FIG. 2 schematically shows an example in which the present invention is applied to an apparatus used for drawing ironing in the can body forming process, and is configured as a mold for a double action press. That is, the inner slide 1 and the outer slide 2 are arranged so as to be vertically movable, and the intermediate plate 3 is fixedly arranged below the outer slide 2 and further below the stroke range of the outer slide 2. A die holder 4 is fixed below the intermediate plate 3, and the die holder 4 is held by a die base 5 disposed below the die holder 4.
[0026]
A nose holder 6 is fixed to the lower surface of the inner slide 1, and a punch drive shaft 7 is attached to the nose holder 6 in a suspended manner. A punch 9 is attached to the lower end of the punch drive shaft 7 for drawing and ironing a cup-shaped intermediate member 8 made of a resin-coated metal plate.
[0027]
The punch 9 is composed of a core material 9a and a sleeve 9b closely fitted to the outer periphery thereof, and at least the sleeve 9b is made of cemented carbide. A spiral flow path 10 is formed at the boundary between the core material 9a and the sleeve 9b, and the water supply / drain path 11 formed through the nose holder 6 and the punch drive shaft 7 is formed in the flow path 10. Is communicated. And this water supply / drainage path 11 is connected to the heat source part (not shown) which circulates, for example, 20-50 degreeC constant temperature water.
[0028]
The outer slide 2 is formed with an opening through which the punch drive shaft 7 and the punch 9 penetrate, and a piston 12 that operates in the vertical direction is provided in the vicinity of the inner periphery of the opening, and is integrated with the piston 12. The pusher pin 13 that moves in a straight line extends downward and a wrinkle presser 14 is attached to the tip (lower end) thereof. The wrinkle presser 14 is a hollow cylindrical member having an opening having a diameter larger than that of the punch 9, and presses the flange (saddle) of the cup-shaped intermediate member 8 with the tip (lower end) thereof. It is configured as follows.
[0029]
Further, the intermediate plate 3 is formed with a through-hole having a diameter larger than that of the wrinkle presser 14, and a wrinkle presser guide 15 having a cylindrical shape is attached to the through-hole. The pusher pin 13 passes through the wrinkle presser guide 15, and the punch drive shaft 7 passes through an opening formed at the center of the wrinkle presser guide 15.
[0030]
A die 16 for drawing and ironing together with the punch 9 is attached to the die holder 4 by a presser plate, and is held so that automatic alignment can be performed along the entering punch 9. The die 16 is an annular plate-like member formed with an opening for molding at the center, and a predetermined clearance is formed between the inner diameter of the opening and the outer peripheral surface of the punch 9. It is a dimension. More specifically, as shown in FIG. 3, the opening in the die 16 includes, in order from the top, a tapered introduction portion 16 a that spreads upward, and a machining portion that is parallel to the central axis and has a predetermined axial length. 16b and a taper-shaped relief portion 16c that extends to the lower side connected to the lower side of the processed portion 16b. Therefore, the part which contacts the said cup-shaped intermediate material 8 which is a workpiece is limited to the process part 16b and its vicinity, Therefore, the location which generate | occur | produces heat | fever with a shaping | molding process, and the location which receives heat with respect to the whole die | dye 16 Limited to a narrow range.
[0031]
Further, a flow path 17 for flowing a temperature adjusting fluid concentrically with the processed portion 16b is formed inside the die 16, and a water supply / drainage path 18 formed in the die holder 4 to which the die 16 is attached. In addition, the lower surface of the die 16 communicates. The flow path 17 and the fluid flowing therethrough constitute a heating / cooling means for adjusting the temperature of the die 16 so as to correspond to the temperature of the punch 9. As shown, a high-temperature heat source unit 19 that supplies a high-temperature fluid at a temperature higher than normal temperature and a low-temperature heat source unit 20 that supplies a low-temperature fluid at a normal temperature or lower are connected to the heat source units 19 and 20 in the middle of the pipe line. The low-temperature fluid and the high-temperature fluid can be selectively supplied to the die 16 by the plurality of switching valves 21 provided in the die 16. In order to perform such control, a controller 22 is provided. The controller 22 corresponds to the die temperature adjusting means of the present invention, and is configured to control the switching valve 21 in accordance with the processing operation of the press machine or in accordance with the temperature rise of the punch from the start of processing. ing.
[0032]
Specifically, the high-temperature heat source unit 19 has hot water of about 50 to 80 ° C., and the low-temperature heat source unit 20 has water at room temperature (about 30 ° C.). At the time of the interruption, water is supplied to the die 16 to be cooled or maintained at about room temperature, and the hot water is supplied to the die 16 by switching from the low temperature fluid to the high temperature fluid immediately before or simultaneously with the start of the molding process. Thus, the temperature of the die 16 is increased.
[0033]
In FIG. 2, reference numeral 23 indicates a knockout, which is arranged on the same axis as the punch 9 and below the punch 9 so as to be movable up and down.
[0034]
Next, the operation of the apparatus configured as described above, that is, the method of the present invention will be described. The cup-shaped intermediate material 8 formed in the previous step is set on the die 16 in a state where the punch 9 and the wrinkle presser 14 are pulled up to the top dead center. In this state, clutches (not shown) of the press machine are turned on, and the inner slide 1 and the outer slide 2 are lowered. As a result, the wrinkle presser 14 first sets the cup-shaped intermediate member 8 by sandwiching the flange of the cup-shaped intermediate member 8 between the upper surface of the die 16. In this state, the lowering of the outer slide 2 stops, but the inner slide 1 further lowers, so that the punch 9 attached thereto enters the inside of the cup-shaped intermediate member 8 fixed to the die 16, The cup-shaped intermediate material 8 together with the die 16 is drawn and ironed.
[0035]
In that case, the constant temperature water mentioned above is supplied with respect to the punch 9, and the temperature is maintained at the predetermined temperature. Further, the above-mentioned water at room temperature is circulated and supplied to the die 16, and the die 16 is maintained in a cooled state or a non-heated state. Therefore, immediately before the start of the forming process, the temperatures of the punch 9 and the die 16 are substantially equal, and the clearance between the two is maintained at the desired dimension. Further, the resin coatings formed on both the inner and outer surfaces of the cup-shaped intermediate member 8 are held within the allowable temperature range for sliding and extending by contacting the punch 9 and the die 16.
[0036]
In addition, by turning on the clutch to start the forming process, hot water is supplied from the high-temperature heat source unit 19 to the die 16 in place of water at about room temperature, and the die 16 is heated and heated. Therefore, the temperature of the die 16 rises as the temperature on the surface side of the punch 9 rises due to the extension and friction of the cup-shaped intermediate member 8 due to the drawing ironing process. Therefore, the temperature difference between the punch 9 and the die 16 does not increase even at the time of rising immediately after the start of processing.
[0037]
When the punch 9 is lowered to the bottom dead center in this manner, the drawing and ironing is finished. First, the punch 9 is lifted together with the inner slide 1 and then the wrinkle presser 14 is lifted, and the wrinkle presser 14 is lifted or wrinkle presser is pressed. The knockout 23 rises with the rise of 14 and the molded product is pushed upward from the die 16. Then, the molded product is sent to the next ironing process (not shown).
[0038]
In addition, since the cup-shaped intermediate material 8 is sent at a short time interval, the drawing and ironing process described above is repeatedly executed according to the supply speed of the cup-shaped intermediate material 8, and the die 16 is subjected to the above-mentioned while the processing is continued. Hot water is supplied and the heating or heat insulation is continued. In the process, when the drawing and ironing process is interrupted due to the supply of the cup-shaped intermediate material 8 being interrupted, that is, when the clutch of the press machine is turned off, the die 16 is replaced with the hot water at room temperature. A certain amount of water is supplied, and the die 16 is relatively cooled. That is, the die 16 is heated and kept warm during processing, and when the processing is not performed, the die 16 is relatively cooled.
[0039]
Therefore, according to the above-described apparatus and method, the die 16 is relatively cooled before the start of drawing and ironing, and the die 16 is heated or kept warm with the start of the processing. As a result, the temperature of the die 16 can be raised in accordance with the rise of the temperature on the surface side of the punch 9, and the temperature difference between the punch 9 and the die 16 can be reduced. Therefore, the amount of change in the thickness of the can barrel wall of the seamless can, which is a molded product, can be reduced, and defects such as a broken barrel and a crack in the resin coating during the molding can be prevented or suppressed.
[0040]
That is, the die is thermally expanded by positively raising the temperature of the die. Then, since a gap is provided between the die holder and the die, it is easy to spread outward. On the other hand, since the opening is formed in the center of the die 16, as a result, the diameter of the opening, that is, the die The clearance between the punch 9 and the die 16 can be maintained by utilizing the phenomenon that the inner diameter of 16 is increased.
[0041]
Here, the result of the experiment conducted by the present inventors is shown in FIG. As shown in FIG. 5, when the temperature of the die 16 is controlled as described above, the amount of decrease in the wall thickness of the can body is reduced. On the other hand, when the temperature of the die 16 is not controlled, the can body The amount of decrease in wall thickness, that is, the error with respect to the target wall thickness, increased. The punch surface temperature is detected using a conventionally known temperature sensor from the start of molding until the temperature of the punch 9 is stabilized or during the molding, and the die 16 is adjusted according to the detected temperature. If the opening and closing control of the high-temperature fluid to be supplied is carried out finely based on experimental data obtained from various molding speeds, can machines, can types, dice machines, coating resin specifications, etc., molding defects can be further reduced. .
[0042]
The above specific example shows an example in which the present invention is applied to drawing ironing. However, the present invention is not limited to the above specific example, and can be applied to an apparatus or method for drawing forming. The present invention can be applied to an apparatus or a method that performs only molding. In addition, as means for cooling and heating the dice in the present invention, any appropriate means other than the water and hot water shown in the above specific examples can be adopted, and for example, warm air, cold air, heating infrared rays, and the like can be used.
[0043]
【The invention's effect】
According to the present invention described above, when being suspended before, or a molding of performing molding using a punch and a die, without performing heating of the die roll, and a punch contrast When starting the molding using a die, dice is heated, the temperature of the die is increased in accordance with the temperature increase of the punches due to forming shape machining. Moreover, since the displacement between the axial centers of the two can be prevented, the clearance between the punch and the die can be maintained, or the displacement between the axial centers of the two can be prevented, and the slip of the resin film provided on the surface of the can body can be prevented. As a result, according to the present invention, it is possible to avoid or suppress molding defects in the process of drawing or drawing ironing of a seamless can and further ironing.
[Brief description of the drawings]
FIG. 1 is a process diagram schematically showing an example of a molding process of a seamless can body targeted in the present invention.
FIG. 2 is a cross-sectional view schematically showing an example of an apparatus according to the present invention used in the can body forming process.
FIG. 3 is an enlarged cross-sectional view of a die forming part.
FIG. 4 is a system diagram showing hot water and a water supply / discharge system for heating and cooling the dies.
FIG. 5 is a diagram showing the amount of change in can body wall thickness according to the present invention and the amount of change in can body wall thickness according to a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 8 ... Cup-shaped intermediate material, 9 ... Punch, 16 ... Dies, 17 ... Flow path, 19 ... High temperature heat source part, 20 ... Low temperature heat source part, 21 ... Switching valve, 22 ... Controller.

Claims (2)

A cup-shaped intermediate material obtained by drawing a resin-coated metal plate with both sides of the metal plate coated with a thermoplastic resin is redrawn or redrawn or ironed with a punch and a die, and has wrinkles. you molded into the bottom can body, the apparatus for manufacturing a dendritic fat coated metal seamless can barrel having a heating and cooling means for heating and cooling the die,
A flow path is formed inside the die, and a high-temperature heat source part that supplies a high-temperature fluid having a temperature higher than normal temperature and a low-temperature heat source part that supplies a low-temperature fluid having a temperature lower than normal temperature are connected to the flow path,
The die heating / cooling means includes a switching valve that selectively supplies a low-temperature fluid and a high-temperature fluid to the die, and the low-temperature fluid is switched to the high-temperature fluid inside the die immediately before or simultaneously with the molding process to supply the high-temperature fluid. And a die temperature adjusting means for supplying and increasing the temperature of the die,
And the die is held in a state of loose insertion in a die holder so as to enable automatic alignment of the die heated and expanded along the approaching punch. Can barrel manufacturing equipment. A cup-shaped intermediate material obtained by drawing a resin-coated metal plate with both sides of the metal plate coated with a thermoplastic resin is redrawn or redrawn or ironed with a punch and a die, and has wrinkles. In the manufacturing method of the resin-coated metal seamless can body to be molded into the bottom can body,
Before the molding process, a low temperature fluid having a normal temperature or less is supplied to the inside of the die so that the die is not heated, and the low temperature fluid is switched to a high temperature fluid immediately before or simultaneously with the start of the molding process. A method for producing a resin-coated metal seamless can body characterized in that the die is heated and expanded in accordance with a rise in temperature, and the clearance between the punch and the die at the time of rising immediately after the start of heating is appropriately maintained .

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