Method for producing an aerosol dome

Abstract

The invention relates to a method for producing an aerosol dome (1) with a dome region (5) comprising a rolled edge (2), which adjoins the upper face and which is arranged on an upper through-opening (32), and comprising a flange region, which adjoins the lower face and has a folded-over section (3), wherein an intermediate stage (52) is provided from a paint-coated blank (R) in one or multiple stages, said intermediate stage having the upper through-opening (32) that is followed downwards by a neck section (14) and further by the dome region (5), which is followed by a straight circumferential flange (15), and the intermediate stage is processed in a processing stage (S9), in which solely the folded-over section (3) is formed.

Description

[0001] TITLE

[0002] METHOD FOR PRODUCING AN AEROSOL DOME

[0003] TECHNICAL FIELD

[0004] The present invention relates to a method for producing an aerosol dome and to an aerosol dome produced using such a method. In particular, it is concerned with providing a method in which the porosity of the coated material is not increased, or only slightly increased, by the forming process.

[0005] STATE OF THE ART

[0006] Pot-shaped metal objects can be formed from a flat sheet of metal in a cold forming process. This typically occurs after a stamping process or combined with a stamping process in a single forming step (deep drawing), in which the finished component is given its final shape. Such processes are used, for example, for the production of pots, spray cans, components in the automotive or furniture industries, for food packaging, etc. Aluminum and tinplate are particularly used as materials.

[0007] Especially when using thin material thicknesses, the forming process must be carefully managed to avoid cracks, wrinkles, etc., and thus rejects or unsatisfactory quality. This applies especially to the formation of conical wall sections, because in contrast to the formation of axially cylindrical wall sections, the guidance in the tool is not guaranteed to the same extent.

[0008] US 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 sections connected by a transition section, and then drawn to substantially its final length and tapered state by drawing material from the transition section. The method optionally also includes a second overlength redraw and a bottom profiling step in which the overdrawn section is used to form the profile.

[0009] EP-A-0 310 726 discloses a drawing method using a cylindrical punch and a frustoconical die. According to the invention, the blank is subjected to one or more drawing operations between a die with a frustoconical inner wall and a cylindrical punch, with the pressure of the clamping means being mitigated so that the metal conforms to the shape of the die during deformation. Application in the production of can bodies from "double-reduced" sheet metal.

[0010] EP-A-3 702 061 describes a method for producing a component from a metal sheet having an at least partially curved or linearly conical region from a cup-shaped blank with a substantially cylindrical wall section. The method is characterized in that it comprises at least the following steps: a stepped drawing step, in which the cylindrical edge section of the blank is formed between a drawing die and a drawing punch displaceably guided in a fold holder into a stepped region with two cylindrical sections; at least one subsequent conical drawing step, in which at least the stepped region is formed into the curved or linearly conical component section between two tools.

[0011] EP-A-1 372 880 and EP-A-3 691 810 describe methods for producing rolled edges. EP-A-3 691 810 relates to a method for producing a rolled edge from a cylindrical edge section of a pipe, in which an initial region of the edge section is rolled by a positively controlled tool. A flanging tool then advances into the rolled edge section and flanges the rolled edge section into a roll. The method is characterized in that the initial region of the edge section is flanged by the tool, which comprises a folding die and a counterholder, at an angle in the range of 75-105 degrees from the axial direction into a substantially radially extending flange.

[0012] WO2019154743 relates to a method for producing a can body consisting of a base and a tubular body made of sheet metal coated on at least one side with a polymer layer. In this method, a round disc is first produced from the sheet metal, which is then deep-drawn into a cup having a polymer layer at least on the outside. This cup is then formed into a can body by wall ironing. Wall ironing occurs in a single stroke by successively moving the cup through a drawing tool and one or more wall ironing rings.

[0013] KR20090054683 describes a manufacturing method for a gas refilling container to prevent material hardening by separately manufacturing an upper cap portion and a lower cap portion and assembling the upper cap portion and the lower cap portion.A manufacturing method for a gas refilling container includes: a step of forming a bottom cap through punching and drawing processes after cutting materials with a cutting machine according to the standard of a bottom mirror plate; a step of forming an upper cap in an upper dome shape with an upper cap press; a body forming step including a surface treatment process for removing foreign matter and preventing corrosion; a flange forming step for a hemming process by extending the top and bottom surfaces of the pipe body; a step of hemming the bottom cap formed on the bottom flange; a step of shiming the upper cap formed on the top surface of the body; and a step of welding a joint formed by the shim steps.

[0014] DE2816860 describes how the end cap of an aerosol can is pressed from sheet metal, with the partially finished workpiece having a flat end face. The end face is removed by first creating a circular groove with a V-shaped cross-section around the rounded edge. This is done using a tool with a sharp-edged circular hole while the cap is held on a mandrel. Once the groove has been formed, the flat surface is removed with a punch pressed downward while the cap is supported on a hollow mandrel.

[0015] CN-A-102219094 discloses an aerosol tank top cover, a molding method, and a die for forming a rear taper of the top cover. The top cover of the aerosol tank includes a generally curved dome; a countersunk notch distributed along the circumferential direction is arranged on the periphery of the curved dome; and the inner wall of the countersunk notch has a rear taper shape. By using the top cover of the aerosol tank, a rounded seam belt of an aerosol tank satisfies a clear structural requirement, is easy and convenient to adjust, and contributes to reducing fluctuations in tank manufacturing quality, thus enabling smooth, automatic high-speed tank manufacturing. Furthermore, the size of the top cover mold is reduced, making the overall package more attractive and simple.The die disclosed by has a simple structure, is technically easy to process, and the round edge of the outer edge of the top cover can be processed at the same time as the rear taper of the inner wall of the countersunk notch, making it suitable for machining and automatic high-speed production.

[0016] CN-A-520947 describes a production process for tin-plated caps for aerosol cans, in which the design and manufacture of molds comprises four separate steps: drawing, correcting the outer diameter and forming, seaming and forming the central hole, and forming the maximum diameter; installing the molds for the first drawing step in a deep-drawing press; installing the molds for the last three steps in another press; and automatic material conveying between different steps. This production process is simple in operation and maintenance and features high material utilization and low production costs.

[0017] PRESENTATION OF THE INVENTION

[0018] It is, inter alia, an object of the present invention to provide a method for producing an aerosol dome which makes it possible to produce a dome which is as stable as possible using as little material as possible (low material thickness) without damaging a lacquer layer or polymer layer located on the material, and in particular not to negatively influence, i.e. to increase, the porosity of the lacquer layer or polymer layer located on the material, which can be confirmed by porosity measurements.

[0019] The present invention accordingly relates to a method according to claim 1 or a use according to claim 15.

[0020] Specifically, the present invention relates to a method for producing an aerosol dome having a dome region with a rolled edge adjacent to the top and arranged at an upper through-opening, and having a flange region with an everted portion adjacent to the bottom. In this process, an intermediate portion is provided from a paint-coated or polymer-coated blank in one or more stages. The intermediate portion has a base, followed downwards by a preferably substantially cylindrical neck portion, further followed by the dome region, which is followed by a circumferential straight flange. This intermediate portion is machined in a processing step in which at least the everted portion is formed in a deep-drawing process.

[0021] According to the invention, this intermediate stage is processed in a processing stage (S7) in which at least the inversion is formed.

[0022] In the processing stage (S7) prior to forming, the intermediate stage rests with the circumferential straight flange, preferably at transport level, on at least three lifting pins without contact with an insertion sleeve. Preferably, the intermediate stage rests exclusively on these lifting pins, preferably four lifting pins.

[0023] The component is then guided by a pressure sleeve onto a scrap drawing die that moves upwards from below. The lifting pins are then retracted, leaving the component exposed with its straight, circumferential flange (held at the bottom by the clamping between the pressure sleeve and the scrap drawing die). While the cup is being drawn, the component is lowered onto an inversion die, preferably without touching the flange. In this position, the part / intermediate stage is again preferably clamped only between a hold-down device and the inversion die, with the pressing sleeve spaced apart.

[0024] The inversion is then formed. Following the inversion, the component with the inversion is lifted from below by the inversion sleeve to the transport level for transport to the next processing station. In other words, contact with the inversion sleeve occurs for the first time in this processing station and only during this final phase.

[0025] This ensures that in the crucial region of the component to be manufactured, no contact occurs between the guide elements in the tool and the component being machined, which could confirm the surface coating.

[0026] According to a preferred embodiment, the proposed method is characterized in that after the lifting pins (which typically have a circular cylindrical cross-section) have moved away, which preferably have a flat support surface at the upper end, and the component with the circumferential straight flange is exposed, the circumferential flange is clamped between a drawing die and a hold-down device before the inversion.

[0027] The inversion is then preferably formed with the flange clamped by lowering an external drawing punch, whereby in the first phase of the process the drawing punch has no contact with the component. Only in the final phase is the inversion brought into the exact shape by the punch.

[0028] Preferably, the base is punched out in the same processing stage (S7), for example by inserting an inner drawing punch at least partially into the waste drawing die.

[0029] In the proposed process, the position of the lifting pins is preferably controlled via pilot pins preferably provided on an upper part of the tool.

[0030] The pressing sleeve can, for example, be designed as a substantially circular-cylindrical component, the upper edge of which comes into contact in the processing stage (S7) only when the component is lifted to the transport level with the inversion from below or by contact with the inversion.

[0031] Furthermore, damage to the component during processing at these and other stations in the crucial region can be avoided by designing the grippers used to transport the components to and from this processing station for the eversion, or to and between further processing stations, as magnetic grippers. Accordingly, contact between such grippers and the component occurs solely via magnetic force and through surface contact without friction. Accordingly, the method is preferably characterized in that the component is gripped with the aid of magnetic grippers during transport from a previous processing stage to the processing stage (S7) for the eversion and / or during transport from the processing stage (S7) for the eversion to a next processing stage.Preferably, the transport is also designed with the aid of magnetic grippers between further processing stages, in particular all processing stages after the processing stage in which the edge of the flange is trimmed to the final contour.

[0032] The magnetic grippers are preferably arranged opposite each other in pairs and are preferably rigid and unsprung on the feed rods of a transfer system.

[0033] The magnetic grippers preferably have at least one magnetic element, preferably in the form of a permanent magnet element or an electromagnetic element, wherein the grippers are preferably designed such that the magnetic element touches the flange on its upper side during transport.

[0034] Such a method is preferably further characterized in that the intermediate stage has an outwardly curved wave at the transition from the dome area to the neck area.

[0035] The processing step for producing the inversion is preferably followed directly or indirectly by at least one further step in which a rolled edge is formed from the neck section.

[0036] According to a further preferred embodiment, the processing step for creating the inversion is followed directly or indirectly by at least one further step in which a preliminary step or the final edge curl is created from the remaining flange. Preferably, if only a preliminary step is formed, this further step is carried out in combination with a step in which a rolled edge is formed from the neck portion. This step is then preferably followed by a further step in which the edge curl is formed. Preferably, no further steps then follow.

[0037] The paint-coated blank is preferably presented in a pot shape with a circumferential flange, a rounded area and a base but without a neck area, and in at least a first stage this blank is formed to the required part height H (typically in the range of 10-40 mm) before creating a rolled edge with an axial neck area, and preferably further in this first stage the radius at the transition area between the flange and the rounded area is reduced, preferably to a radius in the range of 0.2-1.0 mm, particularly preferably in the range of 0.3-0.6 mm. After the first stage, the neck area can be further formed in at least one, preferably two further stages, a second stage and a third stage, in particular the radius of the area between the axial neck area and the radial base can be reduced, preferably to a sharp edge with a radius in the range of 0.05-0.6 mm, particularly preferably in the range of 0.1 - 0.2 mm. According to a further preferred embodiment, in the inversion stage or a subsequent stage, the base, which may have been prepared by scoring, is guided out of the tool as a cup to form an upper through-opening, or is punched out to form the upper through-opening, and preferably subsequently, in a sixth stage, the peripheral edge thus formed is folded over to form a collar, wherein furthermore preferably the fifth stage and the sixth stage are carried out after the two further stages as described above.

[0038] Furthermore, it is preferred if in one stage, preferably in the fifth stage as described above, an outwardly curved wave is formed in the dome area at the transition from the dome area to the neck area.

[0039] In one stage, preferably in the second stage and / or the third stage and / or the fourth stage, additional scoring may be carried out in the transition area between the base and the neck area in order to prepare for the removal of the base.

[0040] A further preferred embodiment is characterized in that, in order to produce the rolled edge from a cylindrical edge section of the neck region, in a first step, preferably in the fifth stage as set out above, an initial zone of the edge section is folded over to form a collar by a positively controlled tool and in a second step, preferably in the further stage as set out above, a flanging die subsequently moves into the folded edge section and flanges it into a roll, wherein in the first step the initial zone of the edge section can be folded over by the tool comprising a folding die and counterholder by an angle in the range of 75-105°, preferably in the range of 80-100°, or in the range of 85-95°, from the axial direction to a substantially radial circumferential flange.

[0041] The bending radius between the circumferential flange and the axial section adjacent thereto is preferably smaller than twice the material thickness of the cylindrical edge section, preferably the bending radius is in the range of 0.5-1.5 times, particularly preferably in the range of 0.75-1.25 times the material thickness of the cylindrical edge section.

[0042] The radial length of the flange is preferably in the range of 2-5 times, preferably in the range of 3-4 times, the material thickness of the cylindrical edge section. The material of the blank is preferably provided with a dense lacquer layer on both sides or at least on the future upper side (outer surface 7). The lacquer can be applied directly to the metal or via an additional adhesion promoter layer. This is preferably a polyester lacquer, an acrylate-based system, a methacrylate-based system, or a polyurethane lacquer. Such a lacquer can be water-based or solvent-based, and it can be cross-linked. The lacquer is preferably applied without VOCs.

[0043] The blank can also be coated with a dense polymer or plastic layer, or even with several such layers. In this case, there are usually additional adhesion promoter layers between the metal and the at least one plastic layer. The plastic layer can be made of polyethylene terephthalate (PET), polypropylene (PP), or polyethylene (PE), or a mixture of such systems. The plastic layer can also contain the usual additives (especially plasticizers, fillers) and, if necessary, dyes or pigments in the usual proportions.

[0044] The thickness of such a paint or plastic layer is typically in the range of 5-40 pm (including any adhesion promoter layer present).

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

[0046] The blank material is preferably sheet steel, preferably tinplate. However, aluminum is also possible.

[0047] The material of the blank (R) is preferably sheet steel, particularly preferably with 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 with a tensile strength, determined according to DIN EN 10002-1:2001, of at least 500 MPa, preferably of at least 550 MPa, particularly preferably at least 575 MPa.

[0048] Or the material of the blank (R) is sheet steel, preferably tinplate of type TH520, material number 1.0384; TH550, material number 1.0373; TH580, material number 1.0382; TH620, material number 1.0374, or the corresponding TS types, each according to DIN EN 10202: 2001, and / or DR8, DR8, DR8.5, or DR9, each according to AISI / ASTM 623.

[0049] The present invention further relates to the use of such a method for producing an aerosol dome for a spray can. The present invention further relates to a tool for carrying out such a method.

[0050] Last but not least, the present invention relates to and describes an aerosol dome for a spray can produced by a method as set out above or in a tool as stated above.

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

[0052] BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Preferred embodiments of the invention are described below with reference to the drawings, which are for illustrative purposes only and are not to be construed as limiting. In the drawings:

[0054] Fig. 1 shows a sequence of steps for producing an aerosol dome from a cup-shaped blank;

[0055] Fig. 2 in a) the situation during conventional pressing out of the component and in b) the situation during conventional pressing in of the component;

[0056] Fig. 3 in a) the open tool according to the new process and in b) the closed tool according to the new process;

[0057] Fig. 4 in a) a side view at the time when the component is placed on the lifting pins and in b) a top view of the situation when the component is placed on the lifting pins;

[0058] Fig. 5 the tool in the situation in which the component is clamped in the base area between the pressure sleeve and the waste drawing die;

[0059] Fig. 6 the situation when before the drawing punch pulls the cup into the waste drawing die;

[0060] Fig. 7 the pilot control of the lifting pins;

[0061] Fig. 8 the situation shortly before inversion;

[0062] Fig. 9 the tool at bottom dead center when not turned;

[0063] Fig. 10 the tool when the part is lifted;

[0064] Fig. 11 the component with magnetic grippers in a perspective view;

[0065] Fig. 12 the tool with the magnetic grippers in the storage position.

[0066] DESCRIPTION OF PREFERRED EMBODIMENTS

[0067] In order to produce an aerosol dome from a pot-shaped blank R made of a thin material coated with a lacquer, several steps are carried out according to the process.

[0068] One possible method is described in connection with Fig. 1. A cup-shaped blank R produced in a previous punching and forming process is fed into the process as shown by the arrow 21. However, it is also possible that the production of this cup-shaped blank R, which is typically first punched out from a flat raw material fed in strip form and then deep-drawn into a cup, which can be done in one or two steps, is carried out as a first step within the scope of the sequence of steps described here.

[0069] This blank R, shown in a), has a circumferential flange 15, which transitions from an initially cylindrical region 53 into a rounded region 17, and which has a closed bottom 18.

[0070] In the processing step indicated by arrow 22 in the first station S1, this blank R undergoes a first drawing step Z1, wherein a punch is inserted into the interior of the blank and the blank is pressed against a die. This results in the component shown in b). In this step, the cylindrical region 53 and parts of the rounded region 17 are formed into a dome region 5, and a neck section 14 is formed from parts of the rounded region 17 and the base 18, which neck section follows the dome region 5 via a transition 20. The base 18 is given a smaller diameter, and a rounding 19 is created at the transition from the base 18 to the neck section 14. The flange 15 essentially remains, and the component does not yet have its final height; this is only created in subsequent steps.

[0071] In a step RP indicated by the arrow 23, the edge is then trimmed, ie the radial length of the flange 15 is adjusted to the desired value; this step takes place here within the framework of stations S2 and S3 (one of which is an empty station), this leads to the component according to c).

[0072] In the processing step indicated by arrow 24 in the fourth station S4, this component undergoes a second drawing step Z2, during which a punch is again inserted into the interior and the component is pressed against a die. This results in the component shown in d). In this step, the dome area 5 is formed and raised, and the neck section 14 is lengthened and its radius reduced.

[0073] In the processing step indicated by arrow 25 in the fifth station S5, this component undergoes a third drawing step Z3, during which a punch is again inserted into the interior and the component is pressed against a die. This results in the component shown in e). In this step, essentially only the previously round area 19 is formed into a substantially sharp edge 31 at the transition from the neck area 14 to the base 18.

[0074] In the machining step indicated by arrow 26 in the sixth station S6, this component undergoes scoring Ri, i.e., a circumferential scoring is created in the transition area 31 between the base 18 and the neck area 14. The scoring function of the scoring during further machining is as follows: The base is prepared to be torn away in the next station and removed from the tool as a cup. This results in the component shown in f).

[0075] The component, as shown in Fig. 1f), is also referred to below as intermediate stage 54. It is characterized in that it has a circumferential flat flange 15, which merges into the dome region 5 in a curved (convex when viewed from the inside) region, which in turn merges into a cylindrical neck section 14 in a curved (convex when viewed from the inside) region, and this neck section 14 is closed off at the top by the base 18. The transition between the base 18 and the neck section 14 is preferably designed as a sharp edge 31 and already has the aforementioned scoring.

[0076] In the crucial processing step in the seventh station S7, indicated by arrow 27, this component is subjected to several steps U simultaneously. Firstly, an inversion 3 is created from parts of the dome area 5. This inversion merges via a vertical section 9 into the flange 15 and radially inwards via an adjacent area 8 into the dome area 5. The material thickening (upsetting) resulting from this type of forming, combined with the support on the press-in sleeve, results in a great load on the coating, which can lead to spalling of the layer, precisely in the area that usually comes into contact with the filling medium. At the same time, in this step, an optional slight outward-directed wave 13 is formed in the dome area 5, which borders on the neck section 14.Also optionally at this stage, the base, which was prepared in station 5, is removed from the tool as a cup, creating a through-hole 32 at the top and a free, straight edge 16 of the cylindrical section 14. The component height is adjusted. This results in the component shown in g).

[0077] In the processing A shown by the arrow 28 in the eighth station S8, this component is subjected to a tilting A. This means that an initial zone of the edge section 16 is folded over by a generally positively controlled tool and only then, in the next stage S9, in a second step, a flanging punch is moved into the folded edge section and this is folded into a roll (rolled edge) 2. In this step S8, the initial zone of the edge section 16 is folded over by a tool comprising a folding punch and counterholder by an angle in the range of 75-105° from the axial direction to form an essentially radial circumferential flange 12. This results in the component shown in h).

[0078] In the processing step W indicated by arrow 29 in the ninth station S9, the rolled edge 2 is formed on this component, and the radial peripheral edge of the flange 15 is folded downward in a preliminary step 11, leaving a horizontal flange section 10. This results in the component shown in i).

[0079] Finally, in the processing RC shown by arrow 30, the final edge curl 4 is generated in the eleventh station S11.

[0080] During this step-by-step process for manufacturing the aerosol cap, flange 15 is inverted. Surface damage may occur on aerosol caps manufactured in this way due to the manufacturing process. However, depending on the can's intended use, such as in the food industry, this must be avoided, as excessive surface or paint damage will cause the cap to begin to rust. Porosity measurements make this damage visible and measurable.

[0081] A situation analysis surprisingly revealed that this damage can be exacerbated during the forming of the part and during part transport. More specifically, it is caused by the pressing sleeve when the part is inverted, and further aggravated by the part's engagement and disengagement from the spring-loaded latches of the feed rod, which feeds the part through the tool between forming steps. The critical area for this application is primarily the inner but also the outer edge area at the edge curl 4, the horizontal flange section 10, the inversion 3, and partially on the inside and outside high on the dome area 5 adjacent to the inversion 3.

[0082] The analysis identified two weaknesses, both individually and in particular in combination, related to the paint problem. These are:

[0083] 1. The first contact with the insertion sleeve when turning inside out

[0084] 2. Further supported by the constant contact with the spring-loaded pawl grippers as the part is transported through the tool.

[0085] The procedure for the inversion, ie the operation described above in station S7 along arrow 27 in Fig.1, is as follows:

[0086] The component is positioned using a feed rod and the corresponding grippers;

[0087] The upper part 38 of the tool moves down;

[0088] The pressure sleeve moves onto the component and presses it against the pressing sleeve;

[0089] The pressure sleeve now controls the pressing sleeve and the component back until the forming begins;

[0090] After forming, the component is pressed again through the pressing sleeve into the latches / grippers of the feed rod in order to transport it to the next station.

[0091] There is initial contact in the curved area at the inner transition between flange 15 and dome section 5 and the press-in sleeve. Due to the necessary shaping of the part from the previous forming steps, this contact is not precisely defined, resulting in a linear contact across the diameter of the part and the press-in sleeve. The press-in sleeve cannot be designed differently in this station due to the decisive drawing die and the lifting function. During forming, this constant contact with the press-in sleeve persists, which can negatively impact the surface coating.

[0092] When the component is pushed into and out of the pawls / grippers of the feed rod in the transfer tool, a recurring contact point with the part is created, rubbing along the pawl surfaces. This is particularly problematic in the stations following the inversion. In eight forming stations, the component is pushed in and out again using a feed rod equipped with pawls consisting of nine pawls. This means that from the blank to the finished lid, the component is pushed in and out 18 times in the same position, which weakens or even damages the paint or surface of the part. Fig. 2 a and b show a simplified representation of the usual process.

[0093] Fig. 2a) shows the situation when the component is ejected within station S7. When component 42 is ejected, the downward-moving pressure sleeve 33 ensures that the spring-loaded latches or grippers 35 snap open. The flange 15 of component 42 and the downward movement of the upper part 38 of the press ensure that the latches 35 open. Once component 42 has passed over the shoulder of latch 35, which is responsible for secure transport, the latch 35 snaps closed again by the spring travel of the gripper 35. There is constant contact at the contact surfaces 36 as long as component 42 remains in the area of ​​the latches 35.

[0094] When pressing into the pawls 35 (as shown in Fig. 2b), the process is similar to the pressing out process. The only difference is that the pressing sleeve 34, which rises from below, ensures that the pawls 35 snap open. The upper part 38 inevitably retracts due to the press stroke. Once the component 42 has reached the transport level, the pawls 35 snap shut again, holding the part securely for transport via spring force.

[0095] In general, it should be noted in connection with the figures that the same reference numerals designate the same components or parts thereof. For the sake of clarity, not all components of the tool designated in the figures are expressly addressed in all of the figures described below. However, the functionality of the components as a whole will be apparent to the person skilled in the art from the overall context of the description.

[0096] Preventing contact of the component with the press-in sleeve is not obvious, as this is required to lift the part to the transport level, and it must therefore be and remain an integral part of the system. In the proposed inversion station S7 described in connection with the following figures, compare Fig. 3a), which shows the tool in the open position with the inserted component 42 according to Fig. 1f), and Fig. 3b), which shows the closed tool at bottom dead center with the inverted component held therein according to Fig. 1g), the component 42 with the flange 15 is at least partially placed on lifting pins 41, typically four of which are distributed around the circumference, in order to avoid the above-described negatively acting contact surface or the contact line with the press-in sleeve 34 in the convexly curved area between the flange 15 and the dome 5.The entire unit in the lower part 39 is then guided back over the component by the pressure sleeve 34 and the two pilot pins 37 in the upper part 38. The press moves downward between angles of 0° and 180°. The inversion station shown in Fig. 3a) essentially corresponds to the overall representation of the inversion station. Here, the tool is shown open. In the subsequent illustrations, some parts are hidden to simplify the detailed process description.

[0097] Fig. 3b) shows the closed tool. In this situation, the forming of the part is complete, and the upward lifting of component 42 is initiated by the press stroke between 180° and 360°. Here, the elements in the lower part 39 of the tool, which are positively controlled by the pressure sleeve 34 and the pilot pins 37, can be seen.

[0098] The detailed process of inverting and positioning the component can be described as follows:

[0099] Fig. 4a) shows a side view of the deposited component 42, and Fig. 4a) a top view. The underside of the flange 15 of the component 42 now rests pointwise on the lifting pins 41 or their surface 49, and is no longer supported from below by the pressing sleeve 34 in the critical curved area inside between the flange 15 and the dome area 5. This avoids the problems caused by this contact line, as described above, since the flat contact of the underside of the flange 15 with the surface 49 of the lifting pins 34 leaves the coating of the material undamaged. During the process, it is ensured that the uppermost edge of the pressing sleeve 34 lies below the component with a sufficient gap throughout the entire process, and contact is only made when the pressing sleeve 34 is used to push the component upwards from below over the lower curvature of the inversion 3 (see below).

[0100] The incoming component 42 is placed onto the lifting pins 34 by the pressing sleeve 43. These are then guided back by the downward movement of the press. The gap between the component 42 and the pressing sleeve 34 shows that the four lifting pins 41 protrude beyond the pressing sleeve 34. This prevents the undefined initial contact described above. The contact area over the four lifting pins 41 is defined and non-critical with regard to damage to the part.

[0101] This can be understood in particular from Fig. 5 and the following figures.

[0102] Fig. 5 shows the moment at which the component 42 is clamped with its base 18 between the pressure sleeve 33 and the waste extraction die 43. The pressure sleeve 33 guides the component 42, still resting on the four lifting pins 41, back onto the waste extraction die 43. The pressure sleeve 33 then inevitably begins to compress.

[0103] Fig. 6 shows the situation immediately before the drawing punch 24 draws the typically already scored base 18 into the waste drawing die 43, when the two pilot pins 37 of the upper part 38 move onto the pressure pins 40 of the lower part 39 and then move the lifting pins 41 away. The component 42 is now completely exposed and is only held between the pressure sleeve 33 and the waste drawing die 43 until the base / cup is removed.

[0104] Fig. 7 shows a section of the situation in which the pilot pins 37 have now moved onto the pressure pins 40 and the lifting pins 41 have moved downwards away from the underside of the flange 15, so that the support 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 lower surface of the hold-down device 46.

[0105] Fig. 8 now shows the situation when the cup / base is drawn out. The component 49 is pushed back onto the drawing die 47. The component is then clamped between the drawing die 47 and the blank holder 46. The blank holder 46 begins to deflect. The pilot pins 37 ensure that the insertion sleeve 34 and the lifting pins 41 always remain controlled away. The actual inversion, driven by the downward movement of the outer drawing punch 45, begins. Since the forming takes place exclusively via the active elements, no unwanted contact occurs that could damage the surface of the component. This is also confirmed by porosity measurements that were carried out directly after this forming process and compared with the old forming method.

[0106] Fig. 9 shows the situation in which the press is at 180° in the so-called bottom dead center. The forming of the component is complete and the press ram opens again. Now the process takes place in reverse. The difference here is that the component now comes into contact with the press-in sleeve 34 for the first time (see also Fig. 10) in order to raise it to the transport level of the feed rod so that it can be picked up by the magnetic grippers described below. With the previous feed rod, the part was constantly being clicked in and out of the catches during the aerosol lid manufacturing process, resulting in recurring, frictional contact. According to a further aspect of the present invention, the part is transported through the tool with magnetic grippers as soon as the edge has been trimmed. This means from station S2 / S3 right up to the finished aerosol lid.These magnetic grippers are designed to eliminate any contact at critical points. They include a magnet 53, the cover plate or retaining projection 51, and the gripper 50 itself (see Fig. 11). Furthermore, the grippers are not spring-loaded, but rather rigidly integrated into the feed rod.

[0107] Fig. 12 shows the position at the end of the feed. Here, the grippers 50 are in a detent position, i.e., they remain stationary above the center point of the respective forming station. This position corresponds to the deposit position shown in Fig. 4. During transport between the forming stations, the magnetic grippers pull the part at least 0.5 mm above the level of the press-in sleeve 41 to ensure that no unwanted contact occurs during transport. In addition, the grippers are designed in such a way that no contact occurs between the component and the grippers 50 when the component is being released or lifted into or out of the grippers. The only contact possible is between the component and the flat underside of the magnetic element 53 when the component is held by the grippers. The shape of the grippers 50 serves as a safety feature to prevent the component from being lost when the feed rate is accelerated.This can be guaranteed due to the accuracy of the system and the manufacturing precision of the grippers.

[0108] The magnetic grippers are used in the process as follows: The upper tool section 38 moves down. As soon as the pressure sleeve 33 touches the component 42, it releases from the grippers, which remain rigidly in position. The magnets 53 embedded in the cover plate 51 lose their holding power over time. At this point, as already mentioned, there is no contact with the transported part. The further the upper section 38 moves together, the further the part moves out of the contact zone of the grippers. For additional safety, run-in surfaces on the grippers serve to gently guide the part should it not be exactly in the desired position. After forming, the pressure sleeve 34 lifts the part 42 back to the transport level. From this point on, the magnets pull the part back against the cover plate 51 to maintain a safety distance of at least 0.5 mm during transport.

[0109] These grippers are installed in the feed rod, which in turn is coupled to the press's gearbox. The first two stations can still be mounted as spring-loaded latches. Since the area that comes into contact with the latches is removed in station 2 by trimming the flange, this does not affect the porosity of the aerosol cap. Only after the flange diameter has been reduced by

[0110] When trimming is defined, the magnetic grippers are used.

[0111] LIST OF REFERENCE SYMBOLS

[0112] 1 Aerosoldome 28 processing in station S8

[0113] 2 rolled edge 29 processing in station S9

[0114] 3 Inversion 30 processing in station S11

[0115] 4 Edge curl 31 sharp edge at transition

[0116] 5 Cathedral area 18 to 14

[0117] 6 inner surface of 5 32 through opening at 14

[0118] 7 Outer surface of 5 33 pressure sleeve

[0119] 8 Adjacent area of ​​5 34 insertion sleeve to 3 35 spring-loaded latch

[0120] 9 vertical section of 3 36 contact surface

[0121] 10 horizontal flange section 37 pilot pins in the upper part

[0122] 11 Preliminary stage of 4 38 upper part

[0123] 12 collar 39 bottom

[0124] 13 Shaft 40 pressure pins in the lower part

[0125] 14 Neck section 41 Lifting pin

[0126] 15 Flange 42 Component

[0127] 16 free straight edge, 43 waste drawing die

[0128] Edge section 44 inner drawing punch

[0129] 17 rounded area 45 outer drawing punch

[0130] 18 floor 46 hold-down device

[0131] 19 Rounding at 18 to 14 47 Drawing die

[0132] 20 Transition from 14 to 5 48 Recording

[0133] 21 Blank feed 49 Support surface of 41

[0134] 22 Machining in station S1 50 Gripper arm

[0135] 23 Machining in station S2 / S3 51 Holding projection, cover plate

[0136] 24 Machining in station S4 52 Fixing screw

[0137] 25 Processing in station S5 53 Magnetic element

[0138] 26 Processing in station S6 54 Intermediate stage

[0139] 27 Processing in station S7

Claims

PATENT CLAIMS 1. A method for producing an aerosol dome (1) having a dome region (5) with a rolled edge (2) adjacent to the top and arranged at an upper through-opening (32), and having a flange region with an inversion (3) adjacent to the bottom, wherein an intermediate stage (54) is provided from a paint-coated or polymer-coated blank (R) in one or more stages, said intermediate stage having a base (18), followed downwards by a neck section (14), further followed by the dome region (5), which is followed by a circumferential straight flange (15), wherein this intermediate stage (54) is machined in a processing stage (S7) in which at least the inversion (3) is formed, and wherein the intermediate stage (54) rests on at least three lifting pins (41) without contact with an insertion sleeve (34) in the processing stage (S7) before the forming with the circumferential straight flange (15),subsequently, the component is guided by a pressing sleeve (33) with the base (18) onto a scrap pulling die (43) moving up from below, subsequently the lifting pins (41) are moved away and the component (42) with the circumferential straight flange (15) is exposed, subsequently the inversion (3) is formed, and subsequently the component (42) with the inversion (3) is lifted from below at the inversion (3) with the pressing sleeve (34) to the transport level for transport to a next processing station.

2. Method according to claim 1, characterized in that after the lifting pins (41), which preferably have a flat support surface (49) at the upper end, have moved away and the component (42) with the circumferential straight flange (15) is exposed, the circumferential flange (15) is clamped between a drawing die (47) and a hold-down device (46) before the inversion (3).

3. Method according to claim 2, characterized in that the inversion (3) is formed with the flange (15) clamped by lowering an outer drawing punch (45).

4. Method according to one of the preceding claims, characterized characterized in that in the same processing stage (S7) the base is punched out, preferably by guiding an inner drawing punch (44) at least partially into the waste drawing die (43).

5. Method according to one of the preceding claims, characterized in that the position of the lifting pins (41) is controlled via pilot pins (37) preferably provided on an upper part (38) of the tool.

6. Method according to one of the preceding claims, characterized in that the pressing sleeve (34) is designed as a substantially circular-cylindrical component, the upper edge of which comes into contact in the processing stage (S7) only when the component (42) with the inversion (3) is lifted from below at the inversion (3) to the transport level.

7. Method according to one of the preceding claims, characterized in that the component is gripped with the aid of magnetic grippers during transport from a previous processing stage to the processing stage (S7) for the inversion and / or during transport from the processing stage (S7) for the inversion to a next processing stage, wherein the transport is preferably also designed with the aid of magnetic grippers between further processing stages, in particular all processing stages after the processing stage in which the edge of the flange (15) is trimmed.

8. Method according to claim 7, characterized in that the magnetic grippers arranged opposite one another in pairs are arranged rigidly and unsprung on feed rods of a transfer system.

9. Method according to claim 7 or 8, characterized in that the magnetic grippers have at least one magnetic element (53), preferably in the form of a permanent magnet element or an electromagnetic element, and wherein the grippers are designed such that the magnetic element (53) touches the flange (15) on its upper side during transport.

10. Method according to one of the preceding claims, characterized in that the processing step (S7) for producing the inversion (3) is followed directly or indirectly by at least one further step (S10) in which the neck section (14) a rolled edge (2) is formed, and / or that the processing step (S7) for producing the everting (3) is followed directly or indirectly by at least one further step (S10) in which a preliminary step (11) or the final edge curl (4) is produced from the remaining flange (15), wherein preferably this further step, if only a preliminary step (11) is formed, is carried out in combination with a step in which a rolled edge (2) is formed from the neck section (14), and wherein then preferably this step is followed by a further step (S11) in which the edge curl (4) is formed.

11. Method according to one of the preceding claims, characterized in that the paint-coated blank (R) is provided in the form of a pot with a circumferential flange (15), a rounded area (17) and a base (18) but without a neck area, and in at least a first stage (S1) this blank is formed to the desired part height (H) before producing a rolled edge (2) with an axial neck area (14), and preferably furthermore in this first stage (S1) the radius at the transition area (38) between the flange (15) and the rounded area (17) is reduced, preferably to a radius in the range of 0.2-1.0 mm, in particular preferably in the range of 0.3-0.6 mm, wherein preferably after the first stage (S1) in at least one, preferably in two further stages, a second stage (S2) and a third stage (S3), the neck region (14) is further formed, in particular the radius of the region (19) between the axial neck region (14) and the radial base (18) is reduced, preferably to a sharp edge (31) with a radius in the range of 0.2-1.0 mm, in particular preferably in the range of 0.3 - 0.6 mm and wherein in particular preferably also in one stage, preferably in the fifth stage (S5), an outwardly curved shaft (13) is formed in the dome region (5) at the transition from the dome region (5) to the neck region (14).

12. Method according to one of the preceding claims, characterized in that in a stage preceding the processing stage (S7) for producing the inversion (3), preferably in the second stage (S2) and / or the third stage (S3) and / or the fourth stage (S4), scoring is carried out in the transition region (31) between the base (18) and the neck region (14).

13. Method according to one of the preceding claims, characterized in that for producing the rolled edge (2) from a cylindrical Edge section of the neck region (14), in a first step, preferably in the fifth stage (S5), an initial zone of the edge section is folded over by a positively controlled tool to form a collar (12), and in a second step, preferably in the further stage (S10), a flanging punch (21) subsequently moves into the folded edge section (12) and flanging it to form a roll (12), wherein in the first step, the initial zone (12) of the edge section is folded over by the tool comprising a folding punch and counterholder by an angle in the range of 75-105°, preferably in the range of 80-100°, or in the range of 85-95°, from the axial direction to a substantially radial circumferential flange (12), wherein preferably the bending radius between the circumferential flange (12) and the axial section adjacent thereto is smaller than twice the material thickness of the cylindrical edge section, preferably that the bending radius is in the range of 0.5-1.5 times, in particular preferably in the range of 0.75-1.25 times the material thickness of the cylindrical edge portion, and / or that the radial length of the flange (12) is in the range of 2-5 times, preferably in the range of 3-4 times the material thickness of the cylindrical edge portion.

14. Method according to one of the preceding claims, characterized in that the material thickness of the blank (R) is in the range of 0.1 - 1 mm, preferably in the range of 0.15-0.4 mm, in particular preferably in the range of 0.18-0.34 mm and / or that the material of the blank (R) is sheet steel, preferably tinplate and / or that the material of the blank (R) is sheet steel with a yield strength, determined according to DIN EN 10002-1:2001, of at least 500 MPa, preferably at least 520 MPa, in particular preferably at least 550 MPa, and / or with a tensile strength, determined according to DIN EN 10002-1:2001, of at least 500 MPa, preferably of at least 550 MPa, in particular preferably at least 575 MPa, and / or that the material of the blank (R) is sheet steel, preferably Tinplate type TH520, material number 1.0384; TH550, material number 1.0373; TH580, material number 1.0382; TH620, material number 1.0374, or the corresponding TS types, each according to DIN EN 10202: 2001 , and / or DR8, DR8,. DR8.5, or DR9, each according to AISI / ASTM 623, and / or that the coating is a coating based on polyester paint, polyurethane paint, acrylate paint, methacrylate paint, or a mixture of such systems, and / or that the polymer coating is a plastic layer based on polybutylene terephthalate, polypropylene, polyethylene, or a mixture of such systems.

15. Use of a method according to any one of the preceding claims for producing an aerosol dome for a spray can.

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