How to make an aerosol dome

Abstract

The present invention relates to a method for manufacturing an aerosol dome (1) having a dome region (5) with a rolled edge (2) adjacent to the upper side and arranged along an upper through hole (32), and a flange region with a folded portion (3) adjacent to the lower side, wherein an intermediate stage (52) is prepared from a blank (R) coated with paint in one or more stages, the intermediate stage having the upper through hole (32) and a neck portion (14) below it, followed by the dome region (5), and then a straight circumferential flange (15), and the intermediate stage is machined in a machining stage (S9), where only the folded portion (3) is formed.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing aerosol domes and aerosol domes manufactured using such a method, and in particular to providing a method in which the porosity of the coated material is increased very little, if at all, by the molding process. [Background technology]

[0002] Cup-shaped metal products may be formed from flat metal parts in a cold-working process. Typically, this is done in a single forming step (deep drawing) after or in combination with a punching process, in which the finished component is formed into its final shape. Such processes are used, for example, for the manufacture of cups, spray cans, components in the automotive or furniture industry, food packaging, etc. The materials used here are, in particular, aluminum and tinplate.

[0003] In particular, when using thin material thicknesses, the forming process must be carried out carefully to avoid cracks, folds, etc., and therefore rejects and poor quality. This applies in particular to the forming of conical wall sections, since their guidance in the tool is not guaranteed to the same extent as when forming axially cylindrical wall sections.

[0004] U.S. Patent Application Publication No. 4,914,937 proposes a method for forming a tapered container, in which the container is first drawn to a partial length with first and second straight sidewall portions connected to each other by a transition portion, and then drawn to substantially its final length and tapered shape by drawing material from the transition portion. The method optionally further includes a step of second redrawing of the excess length and creating a contoured shape for the bottom, using the overdrawn portion to form the contoured shape.

[0005] EP 0 310 726 A1 discloses a drawing method using a cylindrical punch and a frusto-conical die. According to the invention, a blank is drawn one or more times between a die with a frusto-conical inner wall and a cylindrical punch, where the pressure of the clamping means is adjusted to make the metal conform to the shape of the die during deformation. This is applied to the production of "double-rolled" sheet metal can bodies.

[0006] EP 3702061 A1 describes a method for producing a sheet metal component having, at least in some parts, a curved or straight conical region from a cup-shaped blank with a substantially cylindrical wall, characterized in that the method comprises at least the following steps: In the drawing stage, the cylindrical edge portion of the blank is deformed into a region having two cylindrical partial steps between a drawing die and a drawing punch displaceably guided in a blank holder; In at least one subsequent conical drawing, at least the region with the step is transformed between two tools into a curved or straight conical component part.

[0007] EP 1 372 880 and EP 3 691 810 describe methods for forming rolled edges. In the case of EP 3 691 810, this relates to a method for forming a rolled edge from a cylindrical edge portion of a tube, in which an initiation zone of the edge portion is rolled by a force-controlled tool. A flanging tool is then advanced into the rolled edge region and the rolled edge region is flanged into the roll. The method is characterized in that the initiation zone of the edge portion is flanged by a tool comprising a folding punch and a counterholder at an angle ranging from 75 to 105 degrees from the axial direction to form a substantially radial peripheral flange.

[0008] WO 2019 / 154743 relates to a method for producing a can body having a bottom and a tubular body portion from a metal sheet coated on at least one side with a polymer layer. The method involves first producing a circular disk from the metal sheet, then deep-drawing the disk to form a pan having at least an outer polymer layer, which is then formed into a can body by wall ironing. The wall drawing process is carried out in a single stroke by moving the pan through a drawing tool and one or more wall ironing rings in succession.

[0009] Korean Patent Application Publication No. 20090054683 describes a method for manufacturing a gas refill tank, which prevents material hardening by separately manufacturing an upper cap portion and a lower cap portion and then combining the upper and lower cap portions. The method includes the steps of cutting material according to the specifications of the lower end plate using a cutting machine, then forming the lower cap through a punching process and a drawing process, forming the upper cap into the shape of an upper dome using an upper cap press, forming the main body including a surface treatment process to remove foreign matter and prevent corrosion, forming flanges for the seaming process by stretching the upper and lower sides of the tubular body, seaming the lower cap formed on the lower flange, a shim processing stage for the upper cap formed on the main body, and welding the connection formed by the adjustment process.

[0010] German Patent Application Publication No. 2816860 describes a method for stamping end caps for aerosol cans from sheet metal, where the partially finished workpiece has a flat end surface. The end surface is removed by first creating a circular groove with a V-shaped cross section around the rounded edge. To this end, a tool with a sharp-edged circular hole is used while the cap is held on a mandrel. Once the channel is formed, the flat surface is removed with a downward-pressing punch while the cap is supported on the hollow mandrel.

[0011] Chinese Patent Application Publication No. 102219094 discloses an aerosol tank top cover, a molding method, and a die for forming a rear taper on the top cover. The aerosol tank top cover includes a generally curved dome with a circumferentially arranged concave notch along the circumference of the curved dome, and the inner wall of the concave notch has a rear taper. The use of the aerosol tank top cover allows the rounded joint strip for the aerosol tank to meet specific structural requirements. This allows for easy and advantageous adjustment, helping to reduce quality variations in tank manufacturing, facilitating automated high-speed tank manufacturing, and reducing the size of the top cover die, making the overall package simpler and more attractive. The disclosed die has a simple design and can be processed using a technically simple method. The rounded edge on the outer edge of the top cover can be machined simultaneously with the rear taper on the inner wall of the concave notch, making it suitable for machining and automated high-speed manufacturing.

[0012] Chinese Patent Application Publication No. 520947 describes a manufacturing process for tin-plated covers for spray cans, in which the mold design and manufacturing involves four separate steps: stretching and correcting the outer diameter, forming, seaming, forming the center hole, and forming the maximum diameter; assembling the mold for the first drawing step into a deep-drawing press; installing the molds for the last three steps in a separate press; and automatically transporting material between the different steps. The aforementioned manufacturing process is simple in terms of operation and maintenance, has high material utilization, and low manufacturing costs. Summary of the Invention

[0013] The object of the present invention is, inter alia, to provide a method for producing an aerosol dome that allows the production of a dome with maximum stability, using a minimum of material (small material thickness), without damaging the paint or polymer layer arranged on the material, in particular without adversely affecting the porosity of the paint or polymer layer arranged on the material, i.e. without increasing the porosity, which may be confirmed by porosity measurements.

[0014] The subject of the present invention is therefore a method according to claim 1 or a use according to claim 15.

[0015] Specifically, the present invention relates to a method for manufacturing an aerosol dome, the aerosol dome having a dome region with a rolled edge adjacent to the upper side and disposed along the upper through-hole, and a flange region with a folded portion adjacent to the lower side. The intermediate stage is prepared from a paint-coated or polymer-coated blank in one or more stages of the component, the intermediate stage having a base below which is followed by a preferably substantially cylindrical neck portion, further followed by the dome region, which is followed by a straight circumferential flange. The intermediate stage is machined in a machining stage, where at least the folded portion is formed by a deep drawing process.

[0016] According to the invention, this intermediate stage is machined in a machining stage (S7) where at least the folds are formed.

[0017] In the machining stage (S7) before the forming process, the intermediate stage supports the linear circumferential flange, preferably at transfer level, on at least three lift pins without contacting the push-in sleeve, and the intermediate stage is preferably located exclusively on these lift pins, preferably four lift pins.

[0018] The component with its base is then advanced from below onto the waste extraction die, guided by the pressure sleeve, and then the lift pin is released, leaving the component with its straight circumferential flange exposed (held by a clamping action between the pressure sleeve at the base and the waste extraction die).

[0019] During ball extraction, the component is preferably lowered onto the folding bending die without contact with the flanges. In this position, the part / intermediate stage is now preferably clamped only between the hold-down device and the folding bending die, with the push-in sleeve preferably spaced apart therefrom.

[0020] The folds are then formed. After the folding and bending process, the component with the folds is raised from below at the folds to a transfer level by a push-in sleeve for transfer to a subsequent machining station. In other words, contact with the push-in sleeve occurs for the first time at this machining station and only at this final stage.

[0021] It is therefore ensured that there is no contact between the guide elements of the tool and the component being machined in critical areas of the component being manufactured that would damage the surface coating.

[0022] According to a preferred embodiment, the proposed method is characterized in that a lift pin, which preferably has a planar bearing surface at its upper end (and typically has an annular cylindrical cross section), is released to expose a component with a straight circumferential flange, which is then clamped between a drawing die and a hold-down device prior to the folding and bending process.

[0023] The fold is then preferably formed when the flange is clamped by lowering an outer drawing punch, which is not in contact with the component in the first stage of the procedure, and only in the final stage is the punch given its exact shape.

[0024] The base is preferably punched out in the same machining stage (S7), for example by guiding an inner drawing punch at least partially into the waste drawing die.

[0025] In the proposed process, the position of the lift pins is preferably controlled via pilot pins, preferably provided in the upper part of the tool.

[0026] The push-in sleeve may be in the form of a substantially annular cylindrical element, for example, the upper edge of which only comes into contact at the fold or by bearing contact with the fold in the machining stage (S7) when the component with the fold is raised from below to the transfer level.

[0027] Furthermore, by designing the grippers used to transfer the component into and out of this machining station for the folding and bending process or to and between further machining stations as magnetic grippers, damage to critical areas of the component can be avoided during its machining and also at the further stations, so that contact between such grippers and the component occurs only by magnetic forces and as frictionless planar contact.

[0028] Therefore, the method is preferably characterized in that the component is gripped using magnetic grippers during its transfer from the preceding machining stage to the machining stage (S7) for the folding and bending process and / or during its transfer from the machining stage (S7) for the folding and bending process to the subsequent machining stage. Transfer between further machining stages after the machining stage in which the flange edges are cut to their final contour, in particular between all machining stages, is preferably also performed using magnetic grippers.

[0029] The magnetic grippers are preferably arranged in pairs opposite each other and are preferably arranged in a rigid, non-spring loaded manner on the feed rod of the transport system.

[0030] Preferably, the magnetic gripper has at least one magnetic element, preferably in the form of a permanent magnet element or an electromagnetic element, and the gripper is preferably designed so that the magnetic element is in planar contact with the upper side of the flange during transfer.

[0031] Such a method is preferably further characterized in that the intermediate stage has an outwardly curved undulation at the transition from the dome region to the neck region.

[0032] Preferably, at least one further stage in which the rolled edges are formed from the neck portion follows directly or indirectly a machining stage for producing the folds.

[0033] According to a further preferred embodiment, the machining stage for creating the fold is followed directly or indirectly by at least one further stage in which a preliminary stage or final rim curl is created from the remaining flange, this further stage being preferably carried out in combination with a stage in which the rolled edge is created from the neck portion if only one preliminary stage is created, and this stage is followed by a further stage in which the rim curl is created, after which there are preferably no subsequent steps.

[0034] The paint-coated blank is preferably produced in the shape of a cup with a circumferential flange, a rounded region and a base but no neck region, and in at least one first stage, this blank is formed with an axial neck region to the required part height H (typically in the range of 10 to 40 mm) before producing the rolled edge, and the radius of the transition region between the flange and the rounded region is preferably further reduced in this first stage, preferably to a radius in the range of 0.2 to 1.0 mm, particularly preferably to a radius in the range of 0.3 to 0.6 mm.

[0035] After the first stage, in at least one, preferably two further stages, namely the second and third stages, the neck region may be further shaped, in particular the radius of the region between the axial neck region and the radial base may be reduced to a sharp edge with a radius preferably in the range of 0.05 to 0.6 mm, particularly preferably in the range of 0.1 to 0.2 mm.

[0036] According to a further preferred embodiment, in the folding and bending stage or a subsequent stage, the base, possibly prepared by scoring, is guided out of the tool as a ball to form an upper through hole or is punched to form an upper through hole, and then in a sixth stage the resulting peripheral edge is preferably folded back to form a collar, the fifth and sixth stages being further preferably carried out after the two further stages as described above.

[0037] It is further preferred that in one stage, preferably the fifth stage according to the above description, an outwardly curved undulation is formed in the dome region at the transition from the dome region to the neck region.

[0038] In one stage, preferably the second stage and / or the third stage and / or the fourth stage, scoring may further be applied to the transition region between the base and the neck region in preparation for base removal.

[0039] A further preferred embodiment is characterized in that in a first step, preferably the above-mentioned fifth stage, a start zone of the edge portion is folded back by an actively controlled tool to form a collar in order to produce a roll edge from the cylindrical edge portion of the neck region, and then in a second step, preferably the above-mentioned further stage, a flanging punch moves into the folded edge portion and flanging it to form a roll, wherein in the first step the start zone of the edge portion may be folded back by a tool comprising a folding punch and a counterholder at an angle from the axial direction in the range of 75 to 105°, preferably in the range of 80 to 100° or in the range of 85 to 95°, to form a substantially radial circumferential flange.

[0040] The bending radius between the circumferential flange and the adjacent axial portion is preferably smaller than twice the material thickness of the cylindrical rim portion, and the bending radius is preferably in the range of 0.5 to 1.5 times the material thickness of the cylindrical rim portion, particularly preferably in the range of 0.75 to 1.25 times.

[0041] It is more preferable that the radial length of the flange is in the range of 2 to 5 times, and more preferably 3 to 4 times, the material thickness of the cylindrical rim portion.

[0042] The blank material is preferably provided with a dense paint layer on both sides or at least on the future top surface (external surface 7). The paint may be applied directly to the metal or via an additional adhesive layer. This is preferably a polyester paint, an acrylate-based, a methacrylate-based, or a polyurethane paint. Such paints may be water-based or solvent-based and may be crosslinked. The applied paint is preferably zero VOC.

[0043] The blank may also be provided with a high-density polymer or plastic layer, or with several such layers. An additional adhesive layer is typically present between the metal and at least one plastic layer. The plastic layer may be made of polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), or a mixture of these systems. If necessary, the plastic layer may further contain conventional additives (especially plasticizers and fillers), and in particular colorants or pigments, in conventional amounts.

[0044] The thickness of such a coating layer or plastic layer is preferably within the range of 5 to 40 μm (including an adhesive layer, if necessary).

[0045] The material thickness of the blank is usually in the range of 0.1 to 1 mm, preferably in the range of 0.15 to 0.4 mm, and particularly preferably in the range of 0.18 to 0.34 mm.

[0046] The material of the blank is preferably steel sheet, preferably tinplate, although aluminium is also possible.

[0047] The material of the blank (R) is preferably a steel plate, Particularly preferably, it has a yield strength, determined according to DIN EN 10002-1:2001, of at least 500 MPa, preferably at least 520 MPa, particularly preferably at least 550 MPa; and / or has a tensile strength, determined in accordance with DIN EN 10002-1:2001, of at least 500 MPa, preferably at least 550 MPa, particularly preferably at least 575 MPa. Alternatively, the material of the blank (R) is steel sheet, preferably TH520 / material no. 1.0384, TH550 / material no. 1.0373, TH580 / material no. 1.0382, TH620 / material no. 1.0374, or corresponding TS type tinplate, each according to DIN EN 10202:2001 and / or DR8, DR8, DR8.5, or DR9, each according to AISI / ASTM 623.

[0048] Furthermore, the invention relates to the use of such a method for producing aerosol domes for spray cans.

[0049] Furthermore, the invention relates to a tool for carrying out such a method.

[0050] Finally, the invention relates to and describes an aerosol dome for a spray can manufactured according to the method described above or with a tool as defined above.

[0051] Further embodiments are defined in the dependent claims.

[0052] Preferred embodiments of the present invention are described below with reference to the drawings, which are for illustrative purposes only and should not be construed as limiting. [Brief explanation of the drawings]

[0053] [Figure 1] FIG. 1 shows the sequence of stages for producing an aerosol dome from a cup-shaped blank. [Figure 2] Figure 2a) shows the situation during conventional component extrusion, and Figure 2b) shows the situation during conventional component pushing. [Figure 3] Figure 3a) shows an open tool according to the novel method, and Figure 3b) shows a closed tool according to the novel method. [Figure 4]Figure 4a) shows a side view when the component is placed on the lift pins, and Figure 4b) shows a top view of the situation when the component is placed on the lift pins. [Figure 5] FIG. 5 shows the tool with the component clamped between the pressure sleeve and the waste extraction die at the base area. [Figure 6] FIG. 6 shows the situation before the drawing punch draws the ball into the waste drawing die. [Figure 7] FIG. 7 shows the pilot control of the lift pins. [Figure 8] FIG. 8 shows the situation just before the folding bending process. [Figure 9] FIG. 9 shows the tool at bottom dead center during the folding bending process. [Figure 10] FIG. 10 shows the tool when the part is lifted. [Figure 11] FIG. 11 shows a perspective view of a component with a magnetic gripper. [Figure 12] FIG. 12 shows the tool with the magnetic gripper in the parked position. DETAILED DESCRIPTION OF THE INVENTION

[0054] Several stages are carried out in accordance with the present invention to manufacture an aerosol dome from a cup-shaped blank R made of a thin material coated with paint.

[0055] A possible method is described in relation to FIG.

[0056] As indicated by arrow 21, a cup-shaped blank R produced by a prior punching and forming process is fed into the process. However, although the cup-shaped blank R is typically first punched from flat stock supplied in the form of a strip and then deep-drawn to form a loaf, this may be done in one or two steps, or the production of this cup-shaped blank R may be carried out in the series of stages described herein as the first step.

[0057] This blank R, illustrated in a), has a circumferential flange 15 which transitions to a rounded region 17 via an initially cylindrical region 53 and has a closed base 18.

[0058] In the machining process at the first station S1 (indicated by arrow 22), the blank R is subjected to a first drawing process Z1, in which a punch is moved into the blank and pressed against a die. This results in the component illustrated in b). In this process, the cylindrical region 53 and part of the rounded region 17 are transformed into the domed region 5, and the part of the rounded region 17 and the base 18 form the neck portion 14, which continues into the domed region 5 via a transition 20. The base 18 is given a relatively small diameter, and a radius 19 is established at the transition from the base 18 to the neck portion 14. The flange 15 remains substantially intact, and the component is not yet at its final height, which will be established only in a subsequent process.

[0059] In step RP indicated by arrow 23, the edges are then cut, i.e. the radial length of the flange 15 is set to the desired value, this step being carried out at stations S2 and S3 (one of which is an idle station), resulting in a component according to c).

[0060] In the machining process at the fourth station S4 (indicated by the arrow 24), the component is subjected to a second drawing process Z2, in which the punch is now moved inward to press the component against the die. This results in the component illustrated in d). In this process, the dome region 5 is shaped and enlarged, and the neck portion 14 is expanded, reducing its radius.

[0061] In the machining process at the fifth station S5 (indicated by the arrow 25), the component is subjected to a third drawing process Z3, in which the punch is again moved inward to press the component against the die, resulting in the component illustrated in e). In this step, essentially only the previously rounded region 19 is shaped into a substantially sharp edge 31 at the transition from the neck region 14 to the base 18.

[0062] In the machining process at the sixth station S6 (indicated by the arrow 26), the component undergoes a scoring step Ri, i.e., a circumferential score is generated in the region of the transition 31 between the base 18 and the neck region 14, whose role in the further machining process is as follows: the base is cut off in the subsequent station, guided out of the tool and ready to be extracted in the form of a ball. This results in the component illustrated in f).

[0063] The component is also referred to below as intermediate stage 54, as illustrated in FIG. 1f). Notably, intermediate stage 54 has a circumferential planar flange 15 that transitions into a curved (convex from the inside) region to dome region 5, which in turn transitions into a curved (convex from the inside) region to cylindrical neck portion 14, which terminates at the top with base 18. Here, the transition between base 18 and neck portion 14 is preferably formed as a sharp edge 31 and already has the scoring described above.

[0064] In the seventh station S7, during the crucial machining process (indicated by arrow 27), the component undergoes several steps U simultaneously. On the one hand, a fold 3 is generated from a portion of the dome region 5. This fold transitions radially inward to the dome region 5 via the vertical section 9 and to the flange 15 via the adjacent section 8. The combination of the increased material thickness (compression) caused by this type of forming process and the bearing contact with the press-in sleeve results in high loads on the coating, which may result in flaking of the coating layer, especially in the area typically in contact with the filling medium. At the same time, this step optionally forms a slight outward undulation 13 in the dome region 5, which is adjacent to the neck section 14. Similarly, this step also simultaneously guides the base prepared at station 5 out of the tool, optionally in the form of a ball, forming a top through-hole 32 and a straight free end 16 of the cylindrical section 14, thereby establishing the component height. This results in the component illustrated in g).

[0065] In the eighth station S8, in a crucial machining process A (indicated by arrow 28), the component undergoes die bending A. That is, the start zone of the edge portion 16 is folded back by a generally actively controlled tool, and only then, in a second step in the subsequent stage S9, a flanging punch moves into the folded edge portion, which is then flanged to form the roll (roll edge) 2. In this step S8, the start zone of the edge portion 16 is folded back by a tool comprising a folding punch and a counterholder at an angle in the range of 75-105° from the axial direction to form a substantially radial circumferential flange 12. This results in the component illustrated in h).

[0066] In a machining process W (indicated by arrow 29) at the ninth station S9, on the one hand a rolled edge 2 is formed on the component, and on the other hand the radial circumferential edge of the flange 15 is folded downwards in a preliminary stage 11, so that a horizontal flange portion 10 remains. This results in the component illustrated in i).

[0067] Finally, in a machining process RC (indicated by arrow 30) at an eleventh station S11, the final rim curl 4 is produced.

[0068] In this series of stages for manufacturing the aerosol cover, the flange 15 is folded over.

[0069] Aerosol covers produced in this way may suffer from surface damage due to the manufacturing process. However, depending on the application of the can, for example in the food industry, this must be avoided because in the event of significant damage to the surface or paint, the cover will begin to rust. This can be shown / measured through porosity measurements.

[0070] Analysis of the situation surprisingly showed that this damage can be exacerbated during part forming and part transfer. More specifically, it is exacerbated by the push-in sleeve during part folding and bending, and further exacerbated by the engagement and release of the part in the spring-loaded latching device of the feed rod that transports the part between forming steps through the tool. Areas of concern in this application are, in particular, the inner edge region, the outer edge region in the case of the rim curl 4, the horizontal flange portion 10, the fold 3, and the inner and outer portions of the dome region 5 adjacent to the fold 3.

[0071] During the analysis, two weaknesses were identified individually and in combination, particularly with regard to the paintwork issue. These are: 1. Initial contact with the push-in sleeve during the folding bending process. 2. Further aided by continuous contact with spring-loaded latching grippers during part transfer by the tool.

[0072] During the folding bending process, ie the sequence of operations as described above at station S7 along arrow 27 in FIG. 1, is as follows: The components are positioned by feed rods and corresponding grippers. The upper part 38 of the tool moves downwards. A pressure sleeve moves over the component, forcing it against the compression sleeve. The pressure sleeve, in turn, pushes the push sleeve and component back until the molding process begins. After the forming process, the component is again pushed by the push sleeve into the latching device / gripper of the feed rod for transport to the subsequent station.

[0073] The initial contact here is with the push-in sleeve and the curved region at the inner transition between the flange 15 and the dome portion 5. Based on the required shape of the part from the previous forming stage, this initial contact is not precisely defined, and a linear bearing contact is achieved across the diameter of the part and the push-in sleeve. Due to the limited draw die and lift capability, the push-in sleeve cannot be designed differently at this station. Also, this continuous contact with the push-in sleeve continues throughout the forming process and may adversely affect the surface coating.

[0074] As the component is pushed into and out of the latching devices / grippers on the feed rods in the transfer tool, repeated frictional contact points along the latching surfaces sometimes occur. This is particularly problematic in downstream stations of the folding and bending process. In eight forming stations with feed rods equipped with latching devices, the component is pushed into and out of nine latching devices. Therefore, from the blank to the finished cover, the component is pushed in and out 18 times, always in the same position, which can weaken or even damage the paint or part surface. The conventional sequence is shown in simplified form in Figures 2a) and 2b).

[0075] 2a) shows the situation during the ejection of a component at station S7. During the ejection of component 42, the downward movement of pressure sleeve 33 ensures that spring-loaded latching device or gripper 35 clicks open. The downward movement of flange 15 of component 42 and upper part 38 of the press ensures that latching device 35 opens. Once component 42 has passed the shoulder of latching device 35, latching device 35, which is responsible for safe transport, clicks closed again due to the deflection of the spring of gripper 35. As long as component 42 is in the area of ​​latching device 35, there is continuous contact with contact surface 36.

[0076] The behavior during component pushing into the latching device 35 is similar to that of component pushing out, as illustrated in Figure 2b). The only difference here is that the pushing sleeve 34 moving from below upwards ensures that the latching device 35 snaps open. The upper part 38 necessarily moves in the opposite direction due to the pressing stroke. After the component 42 has reached the transfer level, the latching device 35 snaps closed again and holds the part firmly for transfer by spring force.

[0077] It should be noted that, in general, with respect to the drawings, like reference numerals represent like elements or portions thereof. For clarity, not all elements of the tools shown in the drawings will be explicitly referenced within the context of every drawing described below. However, the functionality of the elements as a whole will be apparent to one skilled in the art from the overall context of the specification.

[0078] The prevention of contact between the component and the push-in sleeve is not obvious, since this push-in sleeve must remain part of the system as it is necessary to lift the part to the transfer level.

[0079] See Figures 3a) and 3b) for a proposed folding and bending station S7, which will be described in connection with the subsequent figures. Figure 3a) shows the tool in the open position, with the component 42 according to Figure 1f) inserted. Figure 3b) shows the closed tool at bottom dead center, with the component subjected to folding and bending according to Figure 1g) held therein. The component 42 with the flange 15 is at least partially positioned on the lift pins 41, typically four of which are distributed around the circumference, to avoid contact surfaces or lines with the press-in sleeve 34 in the convexly curved area between the flange 15 and the dome 5, which would result in the above-mentioned negative effect. The entire unit, the lower part 39, is then returned onto the component via the press sleeve 34 and the two pilot pins 37 of the upper part 38. During this time, the press moves downwards at an angle between 0° and 180°. The folding and bending station illustrated in Figure 3a) essentially corresponds to a complete view of the folding and bending station. The tool is shown here in its open state. In the following drawings, some parts are simplified to simplify the description of the detailed sequences.

[0080] In Figure 3b) the closed tool is depicted. In this situation, the forming of the component is completed and the lifting of the component 42 is initiated by an upward press stroke of between 180° and 360°. Elements of the lower part 39 of the tool, which are actively controlled by the pressure sleeve 34 and the pilot pin 37, can now be seen.

[0081] The detailed sequence and component placement during the folding bending process can be described as follows:

[0082] 4a) shows a side view of the placed component 42, and FIG. 4b) shows a plan view. The component 42 now rests at a certain point with the underside of the flange 15 resting on the lift pin 41 or its surface 49, and is no longer supported from below by the push-in sleeve 34 in the critical inner curvature region between the flange 15 and the dome region 5. As a result, the planar bearing contact between the underside of the flange 15 and the upper surface 49 of the lift pin 34 leaves the material coating intact, thus avoiding the aforementioned problems caused by this contact line, as described above. The process ensures that the uppermost end of the push-in sleeve 34 lies below the component with sufficient clearance throughout the entire process, and that contact is only established when the component is displaced upwards from below with the push-in sleeve 34 through the lower curvature of the fold 3 (see below).

[0083] The incoming component 42 is placed on the lift pins 34 by the pressure sleeve 43. These lift pins are then returned as a result of the downward movement of the press. In the gap between the component 42 and the push-in sleeve 34, four lift pins 41 can be seen protruding relative to the push-in sleeve 34. As a result, the undefined initial contact described above is avoided. A bearing area spanning the four lift pins 41 is defined, which is not critical in terms of damage to the part.

[0084] This will be understood in more detail, especially in Figure 5 and the following figures. Figure 5 shows the moment when the component 42 is clamped by its base 18 between the pressure sleeve 33 and the waste extraction die 43. The pressure sleeve 33 returns the component 42, still resting on the four lift pins 41, to the waste extraction die 43. The spring deflection of the pressure sleeve 33 then inevitably begins.

[0085] 6 shows the situation just before the drawing punch 24 extracts the base 18, typically already scored, into the waste extraction die 43, as the two pilot pins 37 in the upper part 38 move towards the pressure pins 40 in the lower part 39, controlling the displacement of the lift pins 41. The component 42 is now fully exposed and remains held between the pressure sleeve 33 and the waste extraction die 43 until the base / ball is extracted.

[0086] 7 shows in detail the situation where the pilot pin 37 has now been moved towards the pressure pin 40 and the lift pin 41 has moved downwards away from the underside of the flange 15, so that the bearing surface 49 is no longer in contact with the underside of the flange 15. In this state, the upper side of the flange is already in contact with the underside of the hold-down device 46.

[0087] FIG. 8 shows the situation when the ball / base is extracted. The component 49 is pushed back onto the drawing die 47. The component is then clamped between the drawing die 47 and the hold-down device 46. The spring deflection of the hold-down device 46 begins. The pilot pin 37 ensures that the displacement of the push-in sleeve 34 and the lift pin 41 remains continuously controlled. The actual folding and bending process begins, driven by the outer drawing punch 45 moving downward. Because the forming process is carried out exclusively through moving elements, no unwanted contact occurs, which could damage the component surface. This is also confirmed by porosity measurements performed immediately after this forming process and compared with conventional forming methods.

[0088] Figure 9 shows the situation when the press is at an angle of 180° at the so-called bottom dead center. The forming of the component is complete and the press ram opens again. The sequence is now reversed. The difference here is that the component now comes into contact with the push-in sleeve 34 for the first time (see also Figure 10) in order to raise it to the transfer level of the feed rod, so that it can be picked up by the magnetic gripper described below.

[0089] With previous feed rods, during the manufacturing process of the aerosol cover, parts were constantly latched and released from the latching device, resulting in repeated frictional contact. According to a further aspect of the present invention, the parts are transported within the tool by magnetic grippers as soon as the edge is cut, i.e., from stations S2 / S3, until the aerosol cover is completed. These magnetic grippers are constructed so that no contact occurs at critical points. They include magnets 53, cover plates or support projections 51, and the grippers 50 themselves (see FIG. 11). The grippers are further integrated into the feed rod in a rigid manner, rather than spring-loaded.

[0090] FIG. 12 shows the position at the end of the feed process. The grippers 50 are now in the detent position, meaning they are held stationary over the center point of each forming station. This position corresponds to the parked position illustrated in FIG. 4. During transfer between forming stations, the magnetic grippers pull the part at least 0.5 mm above the level of the push-in sleeve 41 to ensure no unwanted contact occurs during transfer. Furthermore, the grippers are constructed so that no contact occurs between the component and the gripper 50 during release or lifting of the component from or into the gripper; only contact between the component and the flat underside of the magnetic element 53 is possible the moment the component is held by the gripper. The geometry of the grippers 50 ensures that they do not lose the component when the feed rate is accelerated. This may be guaranteed by the precision of the system and the manufacturing precision of the grippers.

[0091] The magnetic gripper is used in the process as follows: The tool upper part 38 moves downwards. As soon as the pressure sleeve 33 comes into contact with the component 42, the latter is released from the gripper, which remains rigidly in place. The magnets 53 integrated into the cover plate 51 lose their gripping force as they move away. At this moment, as already mentioned, there is no contact with the transported part. As the upper part 38 moves further back, the part moves further away from the gripper's contact zone. For added safety, a push-in surface on the gripper serves to gently advance the part if it is not exactly in the desired position. After the forming process, the push-in sleeve 34 lifts the part 42 back to the transfer level. From here, the magnets again pull the part back against the cover plate 51, ensuring a minimum safety distance of 0.5 mm during transfer.

[0092] These grippers are attached to the feed rod, which in turn is connected to the press gear. As mentioned above, the first two stations may be installed as spring-loaded latching devices. The area that contacts the latching device is removed at station 2 by cutting away the flange, so this still has no effect on the porosity of the aerosol cover. Only after the flange diameter is defined by cutting is the magnetic gripper engaged. [Explanation of symbols]

[0093] 1. Aerosol Dome 2 Roll edge 3 Folding section 4 Rim curl 5 Dome Area Inside 6 5 7 5 exterior 8. Adjacent regions of 5 and 3 9 Vertical part of 3 10 Horizontal flange part 11 Preliminary Stage of 4 12 colors 13 Relief 14 Neck part 15 flange 16 Straight free edge, edge portion 17 Rounded Area 18 base 19 18 to 14 rounded 20 Transition from 14 to 5 21 Blank Supply 22 Machining at station S1 23 Machining at Station S2 / S3 24 Machining at station S4 25 Machining at station S5 26 Machining at station S6 27 Machining at station S7 28 Machining at station S8 29 Machining at Station S9 30 Machining at Station S11 31 Sharp edge at transition from 18 to 14 Through hole at 32 14 33 Pressure sleeve 34 Push-in sleeve 35 Spring-loaded latching device 36 Contact surface 37 Upper section pilot pin 38 Upper part 39 Lower part 40 Lower pressure pin 41 Lift pin 42 Components 43 Waste Extraction Die 44 Inner drawing punch 45 Outer drawing punch 46 Holding Device 47 Drawing die 48 receptacles 49 41 bearing surface 50 Gripper Arm 51 Support projection, cover plate 52 Fastening screw 53 Magnetic Elements 54 Intermediate Stage

Claims

1. A method for manufacturing an aerosol dome (1) having a dome region (5) with a rolled edge (2) adjacent to the upper side and arranged along an upper through-hole (32), and a flange region with a folded portion (3) adjacent to the lower side, comprising: The intermediate stage (54) is prepared in one or more stages from a paint-coated or polymer-coated blank (R), said intermediate stage having a base (18) below which is followed by a neck portion (14), which is further followed by said dome region (5), which is followed by a straight circumferential flange (15); This intermediate stage (54) is machined in a machining stage (S7) in which at least said folding portion (3) is formed; In the machining stage (S7) before the forming process, the intermediate stage (54) supports the linear circumferential flange (15) on at least three lift pins (41) without contacting the push-in sleeve (34); The component then advances with its base (18) onto the waste extraction die (43) from below, guided by the pressure sleeve (33); The lift pins (41) are then released to lay the component (42) with the straight circumferential flange (15) exposed; Then, the folding portion (3) is formed, The component (42) with the folding part (3) is then raised from below at the folding part (3) by the pushing sleeve (34) to a transfer level for transfer to a subsequent machining station. method.

2. 2. The method according to claim 1, characterized in that after the lift pins (41), preferably having planar bearing surfaces (49) at their upper ends, are released and the component (42) is placed with the straight circumferential flange (15) exposed, the circumferential flange (15) is clamped between a drawing die (47) and a hold-down device (46) before the folding and bending process (3).

3. 3. A method according to claim 2, characterized in that the fold (3) is formed when the flange (15) is clamped by lowering an outer drawing punch (45).

4. 4. The method according to claim 1, wherein the base is punched out in the same machining stage (S7), preferably by guiding an inner drawing punch (44) at least partially into the waste drawing die (43).

5. 5. The method according to any one of claims 1 to 4, characterized in that the position of the lift pins (41) is controlled via pilot pins (37), preferably provided in the upper part (38) of the tool.

6. 6. The method according to claim 1, wherein the push-in sleeve (34) is in the form of a substantially annular cylindrical element, the upper edge of which only comes into contact in the machining stage (S7) when the component (42) with the fold (3) is raised from below to the transfer level in the fold (3).

7. the component is gripped with a magnetic gripper during its transfer from a preceding machining stage to the machining stage (S7) for the folding and bending process and / or during its transfer from the machining stage (S7) to a subsequent machining stage for the folding and bending process, 7. The method according to claim 1, wherein the transfer between further machining stages, in particular between all machining stages, after the machining stage in which the edge of the flange (15) is cut is also preferably performed using magnetic grippers.

8. 8. The method of claim 7, wherein the magnetic grippers arranged in pairs opposite each other are arranged in a rigid, non-spring-loaded manner on a feed rod of a transport system.

9. 9. The method according to claim 7 or 8, characterized in that the magnetic gripper has at least one magnetic element (53), preferably in the form of a permanent magnet element or an electromagnetic element, and the gripper is designed so that during transfer the magnetic element (53) is in planar contact with the upper side of the flange (15).

10. at least one further stage (S10) in which a rolled edge (2) is formed from said neck portion (14) follows directly or indirectly said machining stage (S7) for producing said folds (3); and / or at least one further stage (S10) in which a preliminary stage (11) or a final rim curl (4) is produced from the remaining flange (15) follows directly or indirectly the machining stage (S7) for producing the fold (3), this further stage being preferably carried out in combination with the stage in which a rolled edge (2) is produced from the neck portion (14) if only one preliminary stage (11) is produced, this stage being preferably followed by a further stage (S11) in which the rim curl (4) is produced. The method according to any one of claims 1 to 9, characterized in that

11. the lacquered blank (R) is preferably produced in the shape of a cup with a circumferential flange (15), a rounded region (17) and a base (18) but without a neck region, and in at least one first stage (S1) this blank is formed to the desired part height (H) with an axial neck region (14) before producing the rolled edge (2), and the radius of the transition region (38) between the flange (15) and the rounded region (17) is preferably further reduced in this first stage (S1), preferably to a radius in the range of 0.2 to 1.0 mm, particularly preferably to a radius in the range of 0.3 to 0.6 mm, After the first stage (S1), in at least one, preferably two further stages, namely the second stage (S2) and the third stage (S3), the neck region (14) is preferably further shaped, in particular the radius of the region (19) between the neck region (14) in the axial direction and the base (18) in the radial direction is reduced to a sharp edge (31) with a radius preferably in the range of 0.2 to 1.0 mm, particularly preferably in the range of 0.3 to 0.6 mm, In one stage, preferably the fifth stage (S5), an outwardly curved undulation (13) is preferably further formed in the dome region (5), in particular at the transition from the dome region (5) to the neck region (14). The method according to any one of claims 1 to 10, characterized in that

12. 12. Method according to any one of claims 1 to 11, characterized in that in a stage prior to the machining stage (S7) for generating the fold (3), preferably in the second stage (S2) and / or the third stage (S3) and / or the fourth stage (S4), scoring may be performed in the transition region (31) between the base (18) and the neck region (14).

13. In a first step, preferably the fifth stage (S5), in order to produce the roll edge (2) from the cylindrical edge portion of the neck region (14), a start zone of the edge portion is folded back by an actively controlled tool to form a collar (12), then in a second step, preferably the further stage (S10), a flanging punch (21) moves into the folded edge portion (12) and flanges it to form a roll (12), in which in the first step the start zone (12) of the edge portion is folded back by the tool comprising a folding punch and a counterholder at an angle from the axial direction in the range of 75 to 105°, preferably in the range of 80 to 100° or in the range of 85 to 95°, to form a substantially radial circumferential flange (12), the bending radius between the circumferential flange (12) and the adjacent axial portion is smaller than twice the material thickness of the cylindrical edge portion, preferably the bending radius is in the range of 0.5 to 1.5 times the material thickness of the cylindrical edge portion, particularly preferably in the range of 0.75 to 1.25 times the material thickness of the cylindrical edge portion; and / or preferably the radial length of said flange (12) is in the range of 2 to 5 times, preferably in the range of 3 to 4 times, the material thickness of said cylindrical rim portion. The method according to any one of claims 1 to 12, characterized in that

14. The material thickness of the blank (R) is in the range of 0.1 to 1 mm, preferably in the range of 0.15 to 0.4 mm, particularly preferably in the range of 0.18 to 0.34 mm; and / or the material of the blank (R) is a steel plate, preferably tinplate; and / or the material of the blank (R) is a steel plate; having a yield strength of at least 500 MPa, preferably at least 520 MPa, particularly preferably at least 550 MPa, determined according to DIN EN 10002-1:2001; and / or has a tensile strength, determined according to DIN EN 10002-1:2001, of at least 500 MPa, preferably at least 550 MPa, particularly preferably at least 575 MPa; and / or the material of the blank (R) is a steel sheet, preferably TH520 / material no. 1.0384, TH550 / material no. 1.0373, TH580 / material no. 1.0382, TH620 / material no. 1.0374, or a corresponding TS type tinplate, each according to DIN EN 10202:2001 and / or DR8, DR8, DR8.5, or DR9, each according to AISI / ASTM 623; and / or the coated layer is preferably a paint layer based on a polyester paint, a polyurethane paint, an acrylate paint, a methacrylate paint or a mixture of these systems, and / or said polymer coating is preferably a plastic layer based on polybutylene terephthalate, polypropylene, polyethylene or a mixture of these systems. The method according to any one of claims 1 to 13, characterized in that

15. Use of the method according to any one of claims 1 to 14 for producing aerosol domes for spray cans.

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