Patent Application
20250196214
The present invention relates to methods for producing a component from a thin metal sheet, wherein the component has an at least partially curvedly or linearly conical region and is deformed proceeding from a pot-shaped blank having a substantially cylindrical wall portion, and to devices for carrying out such a method, and to components produced using the method. In particular, the method is suitable for the production of aerosol dome elements or capsules, in particular for food products, for example for coffee.
Pot-shaped articles consisting of metal can be deformed from a flat piece of sheet metal in a cold deformation process. This is typically performed after a stamping process or in combination with such a stamping process in a single deformation step (deep drawing), in which the final shape is imparted to the finished component. Such processes are used for example for the production of pots, spray cans (or parts thereof), components in the automotive industry or in the furniture industry, food product packaging, etc. As materials, use is made here in particular of aluminum and tin plate.
In particular if small material thicknesses are used, the deformation process must be performed carefully in order to avoid cracking, creasing etc. and resulting rejects or insufficient quality. This applies in particular to the formation of conical wall regions, because in this case, by contrast to the formation of axially cylindrical wall regions, guidance in the tool is not ensured to the same degree.
U.S. Pat. No. 4,914,937 describes a method for forming a tapering container, in which method the container is firstly drawn to a partial length, with first and second straight side wall portions that are connected to one another by a transition portion, and is then drawn again to substantially its final length and its tapering state by virtue of material being drawn out of the transition portion. The method optionally also includes a second redraw over the length, and a base profiling step that uses the over-drawn portion to form the profile.
EP-A-0310726 discloses a drawing process by means of a cylindrical punch and a frustoconical die. Here, the blank is subjected to one (or several) drawing operation(s) between a die having a frustoconical internal wall and a cylindrical punch, wherein the pressure of the work holder is reduced in order that the metal, as it is deformed, adapts to the shape of the punch. Said document also describes the use for the production of can bodies made of “double reduction” sheet.
EP-A-3702061 discloses a method for producing a component from a metal sheet, said component having an at least partially curvedly or linearly conical region from a pot-shaped blank having a substantially cylindrical wall portion. The method is characterized in that it comprises at least the following steps:
WO 2018/067013 describes a capsule containing a substance for the preparation of a drinkable beverage, wherein the capsule has a capsule body consisting of aluminum, said capsule body having a side wall, an outwardly extending flange, and a seal element on the outwardly extending flange for the purposes of making fluid-tight contact with a surrounding element of a preparation device. The beverage preparation device comprises an annular element having a free contact end that may be provided with a plurality of radially extending open grooves. The seal element is integral with the outwardly extending flange and has a projection. An annular trough between the inner projection foot and the side wall has a base that is axially spaced from the outer projection foot to the base of the capsule body.
The known methods have the problem, inter alia, that they are suitable only above a particular material thickness. If the material thickness is reduced further, for example in order to save material, to be more ecologically sustainable or to satisfy other requirements, problems arise, including cracking, uncontrolled shape formation, etc.
Accordingly, it is an object of the present invention to provide a method for producing a component from an aluminum sheet with a thickness in the range from 0.05 to less than 0.08 mm, which component has an at least partially curvedly or linearly conical region, from a pot-shaped blank having a substantially cylindrical wall portion.
The proposed method is in particular characterized in that it comprises at least the following steps:
Here, the first and the second cylinder portion are encirclingly connected via a transition portion of the stepped region, which transition portion extends substantially radially or conically converges more acutely than the second cylinder portion.
In the step-forming drawing operation, the first cylinder portion is, at least in certain regions, guided internally by the blank holder and clamped between the blank holder and the drawing die, and the second cylinder portion is deformed by the drawing punch.
There is also at least one directly or indirectly subsequent cone-forming drawing operation, in which at least the transition portion and the second cylinder portion of the stepped region are deformed between two tools to form the curvedly or linearly conical component portion. The two tools are formed here at least by a cone-forming drawing operation drawing die and a cone-forming drawing operation drawing punch that is guided movably in a cone-forming drawing operation centering sleeve, and, in the cone-forming drawing operation, the first cylinder portion is, at least in certain regions, guided internally by the cone-forming drawing operation centering sleeve or clamped and/or guided between the cone-forming drawing operation centering sleeve and the cone-forming drawing operation drawing die. The transition portion and the second cylinder portion and the transition portion are deformed between the cone-forming drawing operation drawing punch and cone-forming drawing operation drawing die.
Here, before the step-forming drawing operation, a circular stamped piece is stamped out of a flat metal sheet, and said stamped piece is deformed in a subsequent deformation step to form the pot-shaped blank having a cylindrical wall portion with a blank radius, wherein the free encircling edge of the pot-shaped blank is at least partially of curvedly conically flared form (wherein this conical flare in this case includes a radially extending flange having a fold angle α of up to 90° with respect to the axial opening direction of the component).
Furthermore, in the cone-forming drawing operation, an encircling radial flange and an axial cylindrical rim region are formed at an opening side.
According to a first aspect of the present invention, the method is characterized in that, following the cone-forming drawing operation, a drawing operation is performed in which the conical flare of the free encircling edge (at least the outermost rim region thereof) is form-fittingly folded over to a fold angle α of at least 100° to form a folded-over flare. Following the formation of the folded-over flare, the axial cylindrical rim region and the folded-over flare are rolled at a base side, to form a rolled rim, in a rim rolling operation by means of a rolling punch, wherein the rolled rim preferably protrudes both at a base side and at an opening side beyond the plane of a flange formed in the cone-forming drawing operation.
According to a first preferred embodiment, the method is characterized in that, in the cone-forming drawing operation, an encircling radial flange and an axial cylindrical rim region are formed at an opening side, and, following the cone-forming drawing operation, a groove-forming drawing operation is performed in which an encircling bead directed toward the base is formed between a shaped piece and a die, optionally in combination with a further shaped piece, and at the same time the conical flare of the free encircling edge is form-fittingly folded over to a fold angle α of at least 90° to form a folded-over flare, and in a next step following the formation of the bead and the folded-over flare, the axial cylindrical rim region and the folded-over flare are rolled at a base side, to form a rolled rim, in a rim rolling operation by means of a rolling punch, wherein the rolled rim protrudes both at a base side and at an opening side beyond the plane of the flange.
It is furthermore possible and preferable that, in the (groove-forming) drawing operation, the conical flare of the free encircling edge is form-fittingly folded over to a fold angle α of at least 110°, preferably at least 120°, to form a folded-over flare, wherein the folded-over region is flat or preferably curved in the direction of curvature of the adjoining rolled rim.
The conical flare typically has a radial width in the range from 0.5-2 mm, preferably in the range from 1-1.7 mm.
The method can be performed particularly efficiently and reliably if it is characterized in that, in the (groove-forming) drawing operation, the conical flare is held form-fittingly between a folding punch and a die and is rolled to form the folded-over flare.
According to a second aspect of the present invention that may be used independently of the first aspect of the present invention as mentioned above, but is preferably used in combination with the first aspect, the method is characterized in that, between the step-forming drawing operation and cone-forming drawing operation, a further intermediate drawing operation is performed in which the stepped region having two cylinder portions, the first cylinder portion having a substantially axially extending encircling wall with a first radius and the second cylinder portion following said first cylinder portion along a component axis, adjoining the base and having a substantially axially extending or conically converging encircling wall with a second radius that is smaller than the first radius, is deformed such that a further step is formed from the base or from the base and the transition between base and second cylinder portion, which further step has a cone portion or third cylinder portion, the radius of which is smaller than the second radius.
In particular by means of this additional intermediate drawing operation, when using the claimed thin material but also in conjunction with starting materials in the form of aluminum sheets with a thickness in the range from 0.05 to 0.1 mm, cracks and rejects can be substantially prevented.
Cracks in the material of the component can be prevented in particular if, in the further intermediate drawing operation, a third cylinder portion is formed, and in the further intermediate drawing operation and/or in the step-forming drawing operation, the height h1 and the radius R2 of the second cylinder portion, and in the intermediate drawing operation, the height h2 and the radius R3 of the third cylinder portion, are selected such that, in the cone-forming drawing operation, the convex internal curvature regions of the component come into contact with the external contour of the cone-forming drawing operation drawing punch substantially from the outset, and the convex external curvature regions of the component come into contact with the internal contour of the drawing die of the cone-forming drawing operation substantially from the outset.
Here, the height h1 of the second cylinder portion is preferably set to be a multiple, in the range from 0.8-1.2, of the height ha of the third cylinder portion.
The radii of the second and of the third cylinder portion are defined by the angle of the cone-forming drawing operation resulting from the specified abutment of the tool against the curvature regions.
Owing to the targeted structuring of the component or of the mold used in the further intermediate drawing operation such that, during the subsequent cone-forming drawing operation, the punch and die make contact at the corresponding contact points from the outset and remain in contact throughout the entire cone-forming drawing operation, optimum material guidance is ensured, and cracks are avoided. It is thus possible for even thinner material to be used, in particular within the scope of the claimed thickness in the range from 0.05 to less than 0.08 mm, or, if thicker material as described above is used, rejects can be reduced significantly further.
Particularly few cracks and rejects are generated if the dimensions (height and radii of the steps of the second and third cylinder portions) are set such that, in the cone-forming drawing operation, the base of the component comes into contact with the lower surface of the cone-forming drawing operation drawing punch substantially from the outset. Thus, in the cone-forming drawing operation, controlled contact between the component for processing and the tool is realized at multiple surfaces from the outset. By means of the base of the cone-forming drawing operation drawing punch, that is to say by means of the lower surface thereof, the material of the component is drawn into the die.
Such a method may furthermore preferably be characterized in that, in the further intermediate drawing operation, the transition portion and the second cylinder portion are held form-fittingly between a blank holder and the drawing die, and the cone portion is formed by virtue of a drawing punch that is guided in the drawing die plunging into the base. Typically, the transition portion extends substantially encirclingly radially, and the respective encirclingly extending walls of the first and of the second cylinder portion extend substantially encirclingly axially.
It is furthermore possible that that the cone-forming drawing operation centering sleeve is formed as a blank holder which, during the cone-forming drawing operation, clamps the first cylinder portion and/or the transition portion at least in certain regions between the cone-forming drawing operation blank holder and the cone-forming drawing operation drawing die.
In a further preferred embodiment, the method is characterized in that the ratio of the radius of the first cylinder portion to the radius of the second cylinder portion lies in the range from 2:1-1.1:1, preferably in the range from 1.6:1-1.25:1, particularly preferably in the range from 1.5:1-1.3:1.
It is additionally or alternatively preferable for the ratio of the radius of the first cylinder portion to the base radius of the second cylinder portion or of the cone portion to lie in the range from 2.5:1-1.2:1, preferably in the range from 2.0:1-1.4:1, particularly preferably in the range from 1.9:1-1.5:1.
It is furthermore preferable if the ratio of the axial length of the first cylinder portion to the axial length of the second cylinder portion or of the second cylinder portion and the cone portion lies in the range from 4:1-0.5:1, preferably in the range from 3:1-0.75:1, particularly preferably in the range from 2.5:1-1:1.
It is likewise preferable if the ratio of the radius of the second cylinder portion to the base radius of the cone portion lies in the range from 2.5:1-1.1:1, preferably in the range from 2.0:1-1.2:1, particularly preferably in the range from 1.9:1-1.3:1.
It is typically the case in the proposed method that, before the step-forming drawing operation, a preferably circular stamped piece is stamped, preferably in alternatingly transversely offset fashion, from a flat metal sheet that is preferably supplied in strip form, in particular from a roll, and said stamped piece is deformed in a subsequent deformation step to form the pot-shaped blank having a cylindrical wall portion with blank radius, wherein the free encircling edge of the pot-shaped blank is either folded over to form a radial flange or of curvedly conically flared form, wherein, preferably, the outer diameter of the flare is greater than the blank radius by 1-50 times the material thickness of the metal sheet, preferably, in the case of a curvedly conically flared encircling edge, greater than the blank radius by 2-20 or 5-15 times the material thickness of the metal sheet.
The blank advantageously consists of aluminum or an aluminum alloy with a tensile strength in the range from 80-120 MPa, in particular aluminum of the following types: EN AW-8011A, 8079, 8176, 8021, 8090, sintered 6061 or sintered 2014, in each case in uncoated form or painted, optionally in color, on one side or both sides.
The proposed method may furthermore be characterized in that the at least partially curvedly or linearly conical region forms, with the axis of symmetry of the component, an average angle in the range from 5-40°, preferably in the range from 7-15°, particularly preferably in the range from 8-12°.
The at least partially curvedly or linearly conical region is preferably linearly conical at least in certain regions, and preferably has exclusively linearly conical regions aside from any steps that may be provided.
In the cone-forming drawing operation or in one or more subsequent deformation steps, at the base side adjoining the at least partially curvedly or linearly conical region, there may be formed a further cylindrical or conical region that is preferably connected via a radial region.
In particular, preferably in the cone-forming drawing operation, at the base side adjoining the at least partially curvedly or linearly conical region, there is formed a further conical region, which further conical region, by comparison with the at least partially curvedly or linearly conical region, encloses a greater average angle with the axis of symmetry of the component, preferably a cone angle in the range from 30-80°, particularly preferably in the range from 50-70°.
The method may furthermore be characterized in that, in a transfer station, identical components are processed in parallel in the same stroke on multiple lines operating in parallel, preferably in at least two, particularly preferably 2-8, or 3-5, such parallel lines.
The rolling drawing operation may be followed by further processing steps, in particular selected from the following group: stamping steps; coating steps; application steps, in particular the application of inserts or attachment of seals; filling steps; quality control steps; cleaning steps; mounting steps on further components; wherein these further steps are preferably performed at least in part in the same transfer installation as step-forming drawing operation and cone-forming drawing operation.
The present invention furthermore relates to a device for carrying out a method as described above in the form of a transfer installation having at least one station for the step-forming drawing operation and at least one downstream station for the cone-forming drawing operation, at least one downstream station for the groove-forming drawing operation, and at least one downstream station for the rolling operation, wherein the tool for the step-forming drawing operation comprises a drawing die and a drawing punch that is guided movably in a blank holder, and, in the step-forming drawing operation, the first cylinder portion and/or the transition portion is clamped at least in certain regions between the blank holder and the drawing die, and the second cylinder portion and/or the transition portion is formed by the drawing punch, and wherein the tool for the subsequent cone-forming drawing operation comprises a cone-forming drawing operation drawing die and a cone-forming drawing operation drawing punch that is guided movably in a cone-forming drawing operation centering sleeve, and, in the cone-forming drawing operation, the first cylinder portion and/or the transition portion is guided and/or clamped at least in certain regions between the cone-forming drawing operation centering sleeve and the cone-forming drawing operation drawing die, and the transition portion and/or the second cylinder portion is formed between the cone-forming drawing operation drawing punch and cone-forming drawing operation centering sleeve.
The present invention finally relates to a component produced in a method as described above or in a device as described above.
Further embodiments are specified in the dependent claims.
Preferred embodiments of the invention will be described below on the basis of the drawings, which serve merely for explanatory purposes and are not to be interpreted as limiting.
In the drawings:
Said blank 1 is firstly deformed to form a stepped component 2 in a first deformation step, the intermediate drawing operation or step-forming drawing operation. Said stepped component then firstly has, at an opening side, a first cylinder portion 12, still having the radius R1, which transitions via a curved transition portion 14 into a second cylinder portion 13 having a smaller radius R2. The region of the transitions from 12 via 14 to 13 is also referred to as stepped region 11. The second cylinder portion 13 is followed, toward the base side, by an adjoining short curved region, and then, following the step-forming drawing operation, the base 25 of the component having a base radius RB, which is defined as the radius of the flat region without the transition curvature to the second cylinder portion.
A second deformation step then follows, in which said component 2 is deformed in a first drawing operation, the actual cone-forming drawing operation, to form a conical component 3. In this cone-forming drawing operation, the previously stepped region 11 is deformed to form an in this case curvedly conical region 15. This curvedly conical region 15 is in turn followed by a base region. Here, the base radius RB remains unchanged.
Further drawing operation steps then follow; in a second drawing operation to form the component 4, the cone angle is increased, that is to say the cone is made to converge more acutely, and a cylindrical portion 17 is formed in the base-side region.
In a final drawing operation step, the component 4 is deformed further by virtue of the cylindrical region 17 being deformed to form a radial region 18, which is followed toward the base side by a cylindrical region 19; the component is closed off at the base side by the base 20. This component 5 after the third drawing operation is typically subsequently stamped in the base region, and further operations can then follow, such as the formation of a rolled rim etc.
The tools for implementing the intermediate drawing operation and cone-forming drawing operation to produce such a component are illustrated in
According to the illustration in
Then, as can be seen from
In other words, at the start of this step-forming drawing operation or at least in one phase of the step-forming drawing operation, the blank holder 21 lies against the part, and therefore no creases can form during the deformation. The drawing operation is, in principle, cylindrical. In the end position of the step-forming drawing operation, the metal sheet is fully held. The extent of the intermediate drawing operation or step-forming drawing operation may be adjusted as required. The extent of the intermediate drawing operation/step-forming drawing operation may be adapted to the geometry of the subsequent cone-forming drawing operation.
The tool for the subsequent cone-forming drawing operation is illustrated in
At the commencement of the formation of the conical region, the cylindrical first portion 12 is already guided or even clamped between the centering sleeve 28 and the corresponding mating contour, of cylindrical form, of the drawing die. The centering sleeve 28, and in parallel with this the drawing punch 29 for the cone-forming drawing operation, then move into the drawing die, wherein, at the same time, the first cylinder portion 12 is guided and partially deformed, and in particular the transition portion 14 and the second cylinder portion 13 are deformed by the conical contact surface 31 of the drawing punch 29.
The drawing punch subsequently moves yet further than the centering sleeve 28 into the drawing die 27, until the conical contact surface 30 is reached, that is to say the conical region 15 is deformed between the surfaces 30 and 31, as can be seen in
Owing to the two radii at the start of this cone-forming drawing operation, the component is inherently more resistant to creasing. The free border is reduced in size owing to the two contact points between drawing die and drawing punch. In the end position, the component has, at least in the case of adequately thick materials, been deformed without creasing, and is ready for the second drawing operation.
The complete process of producing the coffee capsule (sequence of steps) is illustrated in
In a cutting drawing operation 63, a pot-shaped blank 1 is deformed in a combined sequential stamping and deformation operation in one tool. It is also possible for only the planar stamped piece to be stamped out in a purely stamping step 62 in a first tool, and to then be deformed in a subsequent tool to form the blank 1. The pot-shaped blank 1 has a closed base portion 8 and an opening, and the wall 8 of the blank is cylindrical, that is to say extends encirclingly axially. In this step, at the same time, a slightly folded-over rim 47 is formed at the free upper edge in the manner of a conical flare at an angle of at most 20° with respect to the axial direction in order to provide stability for subsequent transport and in preparation for the rolling of the rolled rim.
This blank 1 is subsequently deformed in an intermediate drawing operation or step-forming drawing operation 64 to form the stepped component 2. Said stepped component still has the folded-over rim 47 at the free edge, and has a first cylinder portion 12 with the same radius as the original radius of the blank 1, which first cylinder portion however transitions, approximately at the midpoint of the height, into a second cylinder portion 13 of smaller radius via a transition portion 14.
Said stepped component 2 is deformed in a cone-forming drawing operation 65 to form the component 3 having a linearly conical portion. Here, a cylindrical rim region 52 remains, which has substantially the same radius as the original first cylinder portion 12. Said cylindrical rim region transitions via a radial flange into the main conical region 15 of the component 3. The base is likewise formed, with a second cone angle, in a further conical region 69. Both conical regions are formed in this cone-forming drawing operation.
In a subsequent step, in a groove-forming drawing operation 66, the encircling flange at the top is deformed further, as will be discussed in detail further below.
This is followed by a step in which the still axially upwardly projecting rim is rolled, to form a rolled rim 55, in a rim rolling operation 67.
This is followed by an embossing step 68 in which further structures, such as labeling or special structural features of wall portions such as decorative grooves or the like, can be embossed.
The tool for a combined stamping and deformation step for producing the blank 1 from a supplied metal sheet is illustrated in
The tool is designed as a transfer station having an upper carrier plate 41 and a lower carrier plate 42; the plates are guided by means of guide cylinders 23 and can be moved relative to one another only in a vertical direction.
The drawing punch 35 for the drawing operation, and the associated blank holder 33, which radially surrounds the drawing punch, are provided on the upper carrier plate. Said blank holder 33 is however in turn also surrounded by a cutting ring 36 or a cutting die, which has the task of providing the circular planar stamped piece before the deep-drawing process. Said cutting die 36 is supported by a support element 36a, which at the top dead center lies against a stop 36b of the corresponding guide 36d. The cutting ring 36 and blank holder 33 are axially movable relative to one another to a small extent.
Radially at the outside on the lower carrier plate 42, there is firstly a lifter 39 that is braced upward by means of a spring mounting 39. Following this radially to the inside is the annular cutting punch 37 for the cutting drawing operation, said annular cutting punch simultaneously being the deep-drawing die for the drawing operation for forming the blank. This is then followed, in the very center, by the ejector 38 for the cutting drawing operation.
This is not followed by transfer to a subsequent station; instead, the stamped piece 46 that is thus held between blank holder 33 and cutting punch 37 is deformed directly in the same station to form the blank 1 by virtue of the tool moving yet further downward as far as the bottom dead center (BDC), which is illustrated in
Said blank 1 is then transported by means of a transfer installation to the next station, which then performs the step-forming drawing operation 64; the corresponding tool is illustrated in
Here, an upper carrier plate 41 and a lower carrier plate 42 are again provided. The blank holder 21 for the step-forming drawing operation is provided on the upper carrier plate, and the drawing punch 24 is mounted axially movably in said blank holder. A hold-down pin 48 is additionally provided in a central recess of said drawing punch, which hold-down pin is mounted with its guide pin 48a axially movably in said central recess. The front surface of the drawing punch 24 has a concave front surface contour 24a, which corresponds to the rear-side convex contour of the hold-down pin in the foremost region of extent, such that, when the hold-down pin 48 is situated in the fully retracted position in the drawing punch 24, said two elements jointly form a flush, radially extending front surface (see
The cone-forming drawing operation 65 that then follows is performed in the tool illustrated in
Provided on the lower carrier plate is the annular drawing die 27, which forms the mating contour, so to speak, for the external surface of the drawing punch 29. The mating surface for the second cone 29b is provided by the lower cone surface 27b, and the mating surface for forming the main conical region by means of the surface 29a of the drawing punch is provided by the region 27a of the drawing die.
Provided movably in said drawing die 27, in turn, is an ejector 51 which, exactly as in the case of the tool according to
The component after the step-forming drawing operation 2 is then clamped between the hold-down pin 50 and the ejector as soon as said component has been moved by the transfer installation to the position of this station, and the upper tool part is then lowered further downward.
The contours of drawing punch 29 and drawing die 27 then lie fully against one other, and, in particular, the further conical region 69 has also been formed in the base region.
This component 3 is then subjected to the operations already described further above in conjunction with
The rolled rim 55 illustrated in
It is thus possible for coffee capsules to be produced in one or more steps, and with or without a sealing groove. The material thickness used ranges here from 90 my (micrometers) to 120 my. As described, in this method, the rolled rim is fully shaped, without preparation, in the rolling station. When processing relatively thin aluminum foils of 50 my to 80 my, the rolled rim can no longer be produced in the manner described above because the yet thinner material buckles in the rim rolling station, and an acceptable result thus cannot be achieved. Also, the creasing that occurs during the finishing drawing operation is of such magnitude that it can result in side wall cracks and thus unsealed capsules.
In order to form the rolled rim without damage (buckling), preparation for the rolling operation is then necessary. In the sequence of steps, in the first station, a residual flange in the form of the aforementioned conical flare 47 remains on the part.
Before the rolling station, this residual flange or the conical flare 47 is form-fittingly formed through approximately 120° as illustrated in
In this figure, the rim region 47 such as is typically produced during the cutting drawing operation 63 for the purposes of stabilizing the upper free edge is illustrated in a). Typically, this rim region for stabilizing the upper edge is folded over, in the processing steps, through at most 90° with respect to the axial direction (as viewed in the opening direction of the container), and has, for example for the stated thin material with a thickness in the range from 0.05-0.08 mm of coated aluminum, a substantially planar radial flange with a width RA in the range from 1-1.5 mm.
In the tool illustrated in b) for the groove-forming drawing operation, said conical flare 47 is then deformed (or rolled) to form a folded-over flare 74 by virtue of the conical flare being guided form-fittingly between a die 58 and a folding punch 70. Here, the original maximum angle of 90° with respect to the axial direction is folded over, at least in the outermost radial rim region, to more than 90°, typically to 100-120°.
The folded-over flare 74 is subsequently deformed in the rim rolling operation 67 to form the definitive flange as illustrated in c).
By means of these measures, the rolling operation in the rolling station can be performed with a lower initial force, and buckling can be prevented.
To prevent side wall cracks, a further intermediate drawing operation is used, in addition to the existing step-forming drawing operation, to prepare for the finishing drawing operation (cone-forming drawing operation).
The intermediate drawing operations (further intermediate drawing operation and step-forming drawing operation) are adjustable in terms of their extent in order that the volumes can be distributed such that, at the start of the cone-forming drawing operation, the part is as far as possible in contact with the drawing die and the drawing punch, as illustrated in
Here, the component 2′ after the further intermediate drawing operation 71 is illustrated in a). From top to bottom, it is possible to see the folded-over rim 47 or the conical flare, the adjoining first cylinder portion 12, the transition portion 14, and the following second cylinder portion 13. Said second cylinder portion is then followed by a further cone portion 73, which may however also have an axial portion, with a base 82′ which then has a smaller diameter than the base of the component 2 after the step-forming drawing operation.
If, as illustrated in b), the drawing punch 29 for the cone-forming drawing operation then moves into said component 2′ after the further cone-forming drawing operation, the surface of the drawing punch 29 makes contact with the component at a large number of contact points 75, allowing significantly improved guidance and prevention of side wall cracks. As can be seen from the drawing punch that has plunged in further in c), said guidance is provided throughout the further drawing operation, and ultimately leads to the closed tool as per d).
The blank 1 having the folded-over rim 47 is produced analogously to the illustrations above, optionally with a rim of relatively large width and a fold angle of up to 90° (angle between the axis of symmetry in the opening direction of the component and the radially outermost portion of the rim 47).
This component is deformed in the step-forming drawing operation 64 to form the component 2, likewise as discussed above.
Then, in a departure from the sequence of steps illustrated in
This is followed by the cone-forming drawing operation 65 as described above.
This is then followed by a groove-forming drawing operation 66, in which not only is the groove formed but also, as already described above, the folded-over rim 47 is folded over or rolled to form a folded-over flare 74 with a fold angle α of greater than 90°, in this case approximately 120°, with respect to the axial direction.
A rim rolling operation 67 subsequently takes place as described above.
The sequence may be followed by further embossing steps or the like.
The new sequence of steps thus includes the following innovations:
Said residual flange is then form-fittingly angled in station 5. This method has, inter alia, three advantages.
If the tool is closed, this results in the position as illustrated in
This is illustrated in detail in
The blank 1 having the folded-over rim 47 is produced analogously to the illustrations above, optionally with a rim of relatively large width and a fold angle of up to 90° (angle between the axis of symmetry in the opening direction of the component and the radially outermost portion of the rim 47).
This component 1 is deformed in the step-forming drawing operation 64 to form the component 2, likewise as discussed above.
Then, in a departure from the sequence of steps illustrated in
This is followed by the cone-forming drawing operation 65 as described above.
This is then followed by a groove-forming drawing operation 66, in which not only is the groove formed but also, as already described above, the folded-over rim 47 is folded over or rolled to form a folded-over flare 74 with a fold angle α of greater than 90°, in this case approximately 120°, with respect to the axial direction.
A rim rolling operation 67 subsequently takes place as described above.
The sequence may be followed by further embossing steps or the like.
The new sequence of steps thus includes the following innovations:
Said residual flange is then form-fittingly angled in station 5.
In other words, by contrast to the sequence of steps in
Here, the height h1 of the second cylindrical portion 13, the height h2 of the third cylindrical portion 84, the radius R2 of the second cylindrical portion 13 and the radius R3 of the third cylindrical portion 84 are selected such that, during the processing in step 65, as illustrated in
It is furthermore preferably the case in step 71 according to the sequence of steps in
Furthermore, the respective heights and radii are configured such that, during the processing in step 65,
In particular, the height and radius of the second cylindrical portion 13 may be set already during the intermediate drawing operation 64, or may be preset during said intermediate drawing operation 64 and set during the further intermediate drawing operation 71 to the desired height and the desired radius for the optimized cone-forming drawing operation 65. This method as illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 22161973.7 | Mar 2022 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/055756 | 3/7/2023 | WO |
