WO2024105098A1

WO2024105098A1 - Method for producing an aerosol dome

Info

Publication number: WO2024105098A1
Application number: PCT/EP2023/081884
Authority: WO
Inventors: Daniel Moser; Matthias COMMON
Original assignee: Adval Tech Holding Ag
Priority date: 2022-11-18
Filing date: 2023-11-15
Publication date: 2024-05-23

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

TITLE

METHOD FOR PRODUCING AN AEROSOL DOME

TECHNICAL AREA

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 a matter of providing a method in which the porosity of the coated material is not increased or only increased very slightly by the forming process.

STATE OF THE ART

Pot-shaped metal objects can be formed from a flat sheet metal section in a cold forming process. This typically takes place after a punching process or combined with one 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 industry, for food packaging, etc. The materials used in particular are aluminum and tinplate.

Particularly when thin material thicknesses are used, the forming process must be carefully managed to avoid cracks, wrinkles, etc. and thus rejects or insufficient quality. This applies in particular to the formation of conical wall areas, because in contrast to the formation of axially cylindrical wall areas, the guidance in the tool is not guaranteed to the same extent.

US 4,914,937 proposes a method of forming a tapered container in which the container is first drawn to a partial length with first and second straight side wall portions 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.

EP-A-0 310 726 discloses a method for drawing with 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, whereby the pressure of the clamping devices is mitigated so that the metal adapts to the shape of the die during its deformation. Application in the manufacture of can bodies from "double reduced" sheet metal.

EP-A-3 702 061 describes a method for producing a component from a metal sheet with an at least partially curved or linearly conical region from a pot-shaped blank with a substantially cylindrical wall section. The method is characterized in that it comprises at least the following steps: a step drawing, 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 cylinder sections; at least one subsequent conical drawing, in which at least the stepped region is formed into the curved or linearly conical component section between two tools.

EP-A-1 372 880 and EP-A-3 691 810 describe methods for producing rolled edges. EP-A-3 691 810 concerns 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 region and flanging the rolled edge region 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 encircling flange.

WO2019154743 relates to a method for producing a can body consisting of a base and a tubular body made of sheet metal that is coated on at least one side with a polymer layer, in which a round disk is first produced from the sheet metal, which is then deep-drawn into a cup that has a polymer layer at least on the outside, after which this cup is formed into a can body by wall ironing. The wall ironing takes place in a single stroke by moving the cup successively through a drawing tool and one or more wall ironing rings.

KR20090054683 describes a manufacturing method for a gas refill container to prevent hardening of material 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 refill container includes: a step of forming a lower cap by punching and drawing processes after cutting materials with a cutting machine according to the standard of a lower mirror plate; a step of forming an upper Cap in an upper dome shape with an upper cap press; a step of forming a body including a surface treatment process for removing foreign matter and preventing corrosion; a step of forming a flange for a hemming process by extending the top and bottom of the pipe body; a step of hemming the lower cap formed on the lower flange; a step of under-fitting the upper cap formed on the top of the body; and a step of welding a joint formed by the balancing steps.

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

CN-A-102219094 discloses an aerosol tank top cover, a molding method and a die for a rear taper of the aerosol tank top cover, wherein the aerosol tank top cover includes a dome that is generally curved; 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 is in the shape of a rear taper. By using the aerosol tank top cover, a rounded seam belt of an aerosol tank meets a clear structural requirement, is easy and convenient to adjust, and helps to reduce variations in the quality of tank manufacturing, and thus high-speed automatic production of tank manufacturing can be smoothly carried out; and the size of the mold of a top cover is reduced, so that the overall package is 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 upper 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 high-speed automatic production.

CN-A-520947 describes a production process of tin-plated lids for spray cans, where the design and manufacture of moulds comprises the four steps separately: drawing, correcting the outside diameter and forming, hemming and forming the central hole and forming the maximum diameter; installing the moulds for the first drawing step in a deep drawing press; installing the moulds for the last three steps in another press; and automatic material conveying between different steps. The said production process is simple in operation and maintenance and has high material utilization and low production costs.

DESCRIPTION OF THE INVENTION

One of the objects of the present invention is 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. increase, the porosity of the lacquer layer or polymer layer located on the material, which can be confirmed by porosity measurements.

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

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

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

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

The component is then guided by a pressure sleeve with the bottom onto a waste pulling die that is raised from below, and then again the lifting pins are moved away and the component is exposed with the surrounding straight flange (held by the clamp between the pressure sleeve and the waste pulling die at the bottom). During the pulling of the cup, the component is preferably pulled without touching the flange onto an everting die. In this position, the part/intermediate stage is again preferably only clamped between a hold-down device and the everting die, the pressing sleeve is spaced apart.

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

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

According to a preferred embodiment, the proposed method is characterized in that after the lifting pins, which preferably have a flat support surface at the upper end (which typically have a circular cylindrical cross-section), have moved away 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 being turned inside out.

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.

Preferably, the base is punched out in the same processing step (S7), for example by guiding an inner drawing punch at least partially into the waste drawing die.

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.

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 with the inversion is lifted to the transport level from below or by contact with the inversion.

Furthermore, damage to the component during processing at this and other stations in the critical region can be avoided by designing the grippers used to transport the components to and from this processing station for turning or to and between other processing stations as magnetic grippers. Accordingly, contact between such grippers and the component only takes place via magnetic force and by 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 inversion and/or during transport from the processing stage (S7) for the inversion 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.

The magnetic grippers are preferably arranged opposite one another in pairs and are preferably rigid and unsprung on the feed rods of a transfer system.

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 contacts the flange on its upper side during transport.

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

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

According to a further preferred embodiment, the processing step for producing the everting is followed directly or indirectly by at least one further step in which a preliminary step or the final edge curl is produced from the remaining flange, wherein this further step, if only a preliminary step is formed, is preferably carried out in combination with a step in which a rolled edge is formed from the neck section, and wherein this step is then preferably followed by a further step in which the edge curl is formed. Preferably, no further steps then follow.

The paint-coated blank is preferably presented in pot form 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 producing a rolled edge with an axial neck area, and preferably furthermore 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, in particular preferably in the range of 0.3 - 0.6 mm. After the first stage, the neck region 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 region between the axial neck region and the radial base can be reduced, preferably to a sharp edge with a radius in the range of 0.05-0.6 mm, in particular preferably in the range of 0.1-0.2 mm. According to a further preferred embodiment, in the turning-over stage or a subsequent stage, the base, which may have been prepared with a score, is led out of the tool as a bowl to form an upper through-opening, or punched out to form the upper through-opening, and preferably then, in a sixth stage, the peripheral edge formed thereby is folded over to form a collar, wherein the fifth stage and the sixth stage are preferably carried out after the two further stages as set out above.

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.

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 the removal of the base.

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 punch subsequently moves into the folded edge section and flanging 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 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.

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.

The radial length of the flange is further 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 layer of varnish on both sides or at least on the future top side (outer surface 7). The varnish can be applied directly to the metal or via an additional adhesion promoter layer. This is preferably a polyester varnish, an acrylate-based system or a methacrylate-based system or a polyurethane varnish. Such a varnish can be water-based or solvent-based and it can be cross-linked. The varnish is preferably applied without VOC.

The blank can also be provided with a dense polymer layer or plastic layer, or with several such layers. There are then usually additional adhesion promoter layers between the metal and the at least one plastic layer. The plastic layer can consist of polyethylene terephthalate (PET) or polypropylene (PP) or polyethylene (PE), or a mixture of such systems. The plastic layer can also contain the usual additives (in particular plasticizers, fillers) and, above all, dyes or pigments in the usual proportions.

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

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.

The material of the blank is preferably sheet steel, preferably tinplate. However, aluminum is also possible.

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.

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 in accordance with DIN EN 10202: 2001, and/or DR8, DR8, DR8.5, or DR9, each in accordance with AISI/ASTM 623.

Furthermore, the present invention relates to the use of such a method for producing an aerosol dome for a spray can. Furthermore, the present invention relates to a tool for carrying out such a method.

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 indicated above.

Further embodiments are specified in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Fig. 1 shows a sequence of steps for producing an aerosol dome from a pot-shaped blank;

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;

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

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;

Fig. 5 the tool in the situation where the component is clamped in the base area between the pressure sleeve and the waste extraction die;

Fig. 6 the situation when before the drawing punch draws the cup into the waste drawing die;

Fig. 7 the pilot control of the lifting pins;

Fig. 8 the situation shortly before inversion;

Fig. 9 the tool at bottom dead center when unfolded;

Fig. 10 the tool when the part is lifted;

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

Fig. 12 the tool with the magnetic grippers in the storage position.

DESCRIPTION OF PREFERRED EMBODIMENTS

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.

A possible procedure 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 arrow 21. However, it is also possible that the production of this cup-shaped blank R, which is typically first punched out of a flat raw material fed in strip form and then deep-drawn into a cup, which can take place in one or two steps, is carried out as a first step within the scope of the sequence of steps described here.

This blank R, shown in a), has a circumferential flange 15, which passes through an initially cylindrical region 53 into a rounded region 17, and which has a closed bottom 18.

In the processing shown by the arrow 22 in the first station S1, this blank R is subjected to a first drawing Z1, whereby 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 follows the dome region 5 via a transition 20. The base 18 is given a smaller diameter, and a curve 19 is set 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 set in subsequent steps.

In a step RP shown by the arrow 23, the edge is then trimmed, i.e. the radial length of the flange 15 is set to the desired value, this step takes place here within the framework of the stations S2 and S3 (one of which is an empty station), this leads to the component according to c).

In the processing shown by arrow 24 in the fourth station S4, this component is subjected to a second drawing Z2, whereby 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 reshaped and raised, and the neck section 14 is lengthened and reduced in radius.

In the processing shown by arrow 25 in the fifth station S5, this component is subjected to a third drawing Z3, whereby 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 an essentially sharp edge 31 at the transition from the neck area 14 to the base 18.

In the processing shown by the arrow 26 in the sixth station S6, this component is subjected to a scoring Ri, ie in the area of the transition 31 between the base 18 and neck area 14, a circumferential scoring is created, the function of which in the further processing is as follows: The base is prepared in order to be torn away in the next station and pulled out of the tool as a cup. This results in the component shown in f).

The component, as shown in Fig. 1f), is also referred to below as an intermediate stage 54. It is characterized in that it has a circumferential flat flange 15, which in a curved (convex when viewed from the inside) area merges into the dome area 5, which in turn merges in a curved (convex when viewed from the inside) area into a cylindrical neck section 14 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.

In the crucial processing in the seventh station S7, shown by the arrow 27, this component is subjected to several steps U at the same time. On the one hand, an inversion 3 is created from parts of the dome area 5. This inversion passes over a vertical section 9 into the flange 15 and radially inwards over an adjacent area 8 into the dome area 5. The material thickening (compression) 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 the layer flaking off, and this precisely in the area that usually comes into contact with the filling medium. At the same time, in this step, a slight outward-facing wave 13 is optionally formed in the dome area 5, which borders on the neck section 14. Also at the same time, optionally in this stage, the base that was prepared in station 5 is guided out of the tool as a bowl, so that a through opening 32 results at the top and a free straight edge 16 of the cylindrical section 14, and the component height is adjusted. This results in the component shown in g).

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 tool that is usually controlled in a forced manner and only then, in the next stage S9, in a second step, a flanging punch is inserted into the folded edge section and this is flanged 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 an essentially radial circumferential flange 12. This results in the component shown in h).

In the processing W shown by arrow 29 in the ninth station S9, On the one hand, the rolled edge 2 is formed in this component, and on the other hand, the radial peripheral edge of the flange 15 is folded downwards in a preliminary stage 11 so that a horizontal flange section 10 remains. This results in the component shown in i).

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

In this sequence of steps for producing the aerosol lid, the flange 15 is turned inside out. With aerosol lids produced in this way, surface damage can occur due to the manufacturing process. However, depending on how the can is used, such as in the food industry, this must be avoided, as if the surface or paint is damaged too much, the lid will start to rust. This damage can be made visible/measurable by measuring the porosity.

A situation analysis has surprisingly shown that this damage can be caused during the forming of the part and during part transport. More precisely, by the pressing sleeve when the part is turned inside out and further increased by the part being clicked in and out of the spring-loaded latches of the feed rod, which feeds the part through the tool between the forming steps. The critical area for the application is primarily the inner but also the outer edge area at the edge curl 4, the horizontal flange section 10, the turn-over 3 and partly on the inside and outside high on the dome area 5 adjacent to the turn-over 3.

The analysis identified two weak points, both individually and in particular in combination, related to the paint problem. These are:

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

2. Further supported by the constant contact with the spring-loaded jaw grippers as the part is transported through the tool.

The procedure for the eversion, i.e. the operation described above in station S7 along arrow 27 in Fig.1, is as follows:

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

The upper part 38 of the tool moves down;

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

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

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.

There is an initial contact in the curved area at the inner transition between the flange 15 and the dome section 5 and the pressing sleeve. This is not precisely defined due to the necessary shaping of the part from the previous forming stages. and a line support is created across the diameter of the part and the pressing sleeve. The pressing sleeve cannot be designed differently in this station due to the decisive drawing die and the lifting function. During the forming process, this constant contact with the pressing sleeve remains and can therefore have a negative effect on the surface coating.

When the component is pushed in and out of the latches/grippers of the feed rod in the transfer tool, a recurring contact point with the part is created, rubbing along the latch surfaces. This is particularly problematic in the stations from the turning inside out. In eight forming stations, the component is pushed in and out again using a feed rod equipped with latches made up of nine latches. In other words, 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. The usual process is shown in simplified form in Fig. 2 a and b.

Fig. 2a) shows the situation when the component is pressed out within the S7 station. When the component 42 is pressed out, the downward-moving pressure sleeve 33 ensures that the spring-loaded latches or grippers 35 snap open. The flange 15 of the component 42 and the downward movement of the upper part 38 of the press ensure that the latches 35 open. If the component 42 is over the shoulder on the latch 35, which is responsible for safe transport, the latch 35 snaps shut again by the spring travel of the gripper 35. There is constant contact on the contact surfaces 36 as long as the component 42 is in the area of the latches 35.

When pressing into the latches 35 as shown in Fig. 2b), the process is similar to that of pressing out. The only difference is that the pressing sleeve 34, which moves up from below, ensures that the latches 35 snap open. The upper part 38 inevitably moves back due to the press stroke. After the component 42 has reached the transport level, the latches 35 snap shut again and hold the part securely for transport via the spring force.

In general, it should be noted in connection with the figures that the same reference symbols 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 the context of all 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.

Preventing the component from coming into contact with the press sleeve is not obvious, as the latter is needed to lift the part to the transport level and must therefore be and remain part of the system. In the proposed turning station S7 described in connection with the following figures (see Fig. 3a), which shows the tool in the open position with the component 42 inserted as per Fig. 1f), and Fig. 3b), which shows the closed tool at bottom dead center with the turned-over component held therein as per Fig. 1g), the component 42 with the flange 15 is at least partially placed on lifting pins 41, typically four of them distributed around the circumference, in order to avoid the negatively acting contact surface described above or the contact line with the pressing 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 controlled back over the component by the pressing sleeve 34 and the two pilot pins 37 in the upper part 38. The press moves downwards between angles of 0°-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 other figures, some parts are hidden to simplify the detailed description of the process.

The closed tool is shown in Fig. 3b). In this situation, the forming of the part is completed and the lifting of the component 42 is initiated by the press stroke between 180° and 360° upwards. Here you can see the elements in the lower part 39 of the tool that are positively controlled by the pressure sleeve 34 and the pilot pins 37.

The detailed process of turning and positioning the component can be described as follows:

Fig. 4a) shows a side view of the deposited component 42 and Fig. 4a) a top view. The component 42 now rests with the underside of the flange 15 at certain points on the lifting pins 41 or on 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 means that the problems mentioned above can be avoided 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 with a sufficient gap below the component during the entire process, and contact is only made when the pressing sleeve 34 is used to move the component upwards from below over the lower curvature of the inversion 3 (see below).

The incoming component 42 is placed on the lifting pins 34 by the pressure sleeve 43. These are then controlled back by the downward movement of the press. Gap between the component 42 and the pressing sleeve 34, it can be seen that the four lifting pins 41 protrude from the pressing sleeve 34. This avoids the undefined initial contact, as described above. The contact area over the four lifting pins 41 is defined and not critical with regard to damage to the part.

This can be understood in particular by referring to Fig. 5 and the following figures.

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.

Fig. 6 shows the situation immediately before the drawing punch 24 draws the base 18, which is typically already scored, 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 now move the lifting pins 41 away. The component 42 is now completely free and is only held between the pressure sleeve 33 and the waste drawing die 43 until the base/cup is removed.

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 top of the flange is already in contact with the lower surface of the hold-down device 46.

Fig. 8 now shows the situation when the cup/base is pulled out. 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 hold-down device 46 begins to compress. The pilot pins 37 ensure that the pressing sleeve 34 and the lifting pins 41 always remain controlled away. The actual turning over begins, driven by the outer drawing punch 45 being lowered. Since the forming takes place exclusively via the active elements, there is no unwanted contact that could damage the surface of the component. This is also confirmed by porosity measurements that were carried out directly after this forming and compared with the old forming method.

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 pressing 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 taken over by the magnetic grippers described below. With the previous feed rod, the part was always clicked in and out of the latches during the manufacturing process of the aerosol lid, which meant that there was constant frictional contact. According to a further aspect of the present invention, the part is transported through the tool using magnetic grippers as soon as the edge has been trimmed. That is, from station S2/S3 to the finished aerosol lid. These magnetic grippers are designed in such a way that no contact occurs at the critical points. They contain a magnet 53, the cover plate or retaining projection 51 and the gripper 50 itself, see Fig. 11. The grippers are also not spring-loaded, but are rigidly integrated into the feed rod.

Fig. 12 shows the position at the end of the feed. Here the grippers 50 are in a rest position, i.e. they remain still above the center 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 0.5mm 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 when the component is released or lifted out of or into the grippers there is no contact whatsoever between the component and the grippers 50; only contact between the component and the flat underside of the magnetic element 53 is possible when the component is held by the grippers. The shape of the grippers 50 is for safety reasons so that the component is not lost when the feed accelerates. This can be guaranteed due to the accuracy of the system and the manufacturing accuracy of the grippers.

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

These grippers are installed in the feed rod, which in turn is coupled to the press's gear box. 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 yet have any influence on the porosity of the aerosol cap. Only after the flange diameter has been

When trimming is defined, the magnetic grippers are used.

LIST OF REFERENCE SYMBOLS

1 Aerosol dome 28 processing in station S8

2 Roll edge 29 Processing in station S9

3 Inversion 30 Processing in station S11

4 Edge curl 31 sharp edge at transition

5 Cathedral area 18 to 14

6 Inner surface of 5 32 Through hole at 14

7 Outer surface of 5 33 Pressure sleeve

8 Adjacent area of 5 34 insertion sleeve to 3 35 spring-loaded latch

9 vertical section of 3 36 contact surface

10 horizontal flange section 37 pilot pins in the upper part

11 Preliminary stage of 4 38 Upper part

12 Collar 39 Bottom

13 Shaft 40 Pressure pins in the lower part

14 Neck section 41 Lifting pin

15 Flange 42 Component

16 free straight edge, 43 waste die

Edge section 44 inner drawing punch

17 rounded area 45 outer drawing punch

18 Floor 46 Hold-down

19 Rounding at 18 to 14 47 Drawing die

20 Transition from 14 to 5 48 Recording

21 Blank feed 49 Support surface of 41

22 Machining in station S1 50 Gripper arm

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

24 Machining in station S4 52 Fixing screw

25 Processing in station S5 53 Magnetic element

26 Processing in station S6 54 Intermediate stage

27 Processing in station S7

Claims

PATENT CLAIMS

1 . Method for producing an aerosol dome (1) with a dome region (5) with a rolled edge (2) on the upper side and arranged at an upper through-opening (32) and with a flange region with an inversion (3) on the lower side, wherein an intermediate stage (54) is provided from a paint-coated or polymer-coated blank (R) in one or more stages, which intermediate stage has 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 processed in a processing stage (S7) in which at least the inversion (3) is formed, and wherein the intermediate stage (54) in the processing stage (S7) rests with the circumferential straight flange (15) on at least three lifting pins (41) without contact with a pressing sleeve (34) before the forming, then the component is pressed by a pressing sleeve (33) with the bottom (18) is guided onto a waste pulling die (43) which moves up from below, then the lifting pins (41) are moved away and the component (42) with the circumferential straight flange (15) is exposed, then the inversion (3) is formed, and then 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 everting (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 step (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-in 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) contacts 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 portion (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 portion (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 area (14) is further formed, in particular the radius of the area (19) between the axial neck area (14) and the radial base (18), 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 in addition in one step, preferably in the fifth step (S5), in the dome region (5) at the transition from the dome region (5) to the neck region (14) an outwardly curved shaft (13) is formed.

12. Method according to one of the preceding claims, characterized in that in a stage preceding the processing stage (S7) for producing the everting (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 to form a collar (12) by a positively controlled tool 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 of the 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 paint is a paint layer 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 one of the preceding claims for producing an aerosol dome for a spray can.