EP1481744A1 - Process and apparatus for producing a shaped article, as well as shaped article, in particular a container bottom - Google Patents

Abstract

A method for pressing and spinning of large metal forms, e.g. aluminium bowls, has the workpiece clamped in a press (14) to form the base profile and rotated past fixed heaters and fixed rollers to shape the side of the bowl. The heaters are mounted on adjustable supports to set the optimum heating, and are fired with gas or oil. The spinning tools are fixed on the inside and outside of the pressed shape.

Description

The invention relates to a method and a device for metal pressing Blanks, in particular made of aluminum, to form a curved molding, in particular a container bottom, with the in the preamble of claims 1, 13 and 22 features mentioned.

In metal spinning, a blank is available as a sheet blank or preform set in rotation and by an advanced and advanced pressing tool brought into the desired, rotationally symmetrical molded part. An overview about known spinning processes is in "Blech-Rohr-Profiles" 28 (1981) 11, Pages 514 - 517 removable. The blank is used in the known pressing processes centered in a pressure chuck, the outer contour of the inner contour of the desired molded part. The press tool in the form of a Press roller, however, follows the outer contour of the desired molded part, see above that the blank is formed between the spinning roller and the spinning chuck can. In modern spinning devices, the spinning roller is either over copy templates or motion-controlled via an NC control.

Moldings that are particularly common in practice are container bottoms from Pressure vessels with a cylindrical jacket. According to the degree of curvature of the calotte A distinction is made between container bases, dished ends, arched bases, Hemispherical floors as well as plate floors and flat floors. With decreasing curvature or with increasing radius of curvature, the simplifies Manufacture so that especially bobbin and arched floors a one-piece blank.

The methods in which a blank, in particular, are considered to be generally known a sheet, within a first shaping step to a defined one Total radius is formed and then in the outer area the sheet is formed with a particularly strong radius becomes. The resulting during these shaping processes Tensions are reduced by subsequent annealing at approx. 300 - 350 ° C eliminated.

DE 35 34 796 A1 describes a method and a device known for the shaping of sheets and plates. Basically here the workpieces to be deformed are clamped so that there is an elastic deformation. Then in a near surface Layer of the workpiece under elastic tension the forming energy introduced by means of electrically induced heat, so that the material under the influence of the elastic tension within this layer comes to flow by the deformation resistance by increasing the temperature is overcome. In this way, direction-independent deformations can be achieved achieve significant proportions without leaving any traces Tension, such as when stretching, comes because for those The intended means are supports that have practically no clamping surfaces attack the workpiece. This publication represents only that general prior art, the introduction of a quantity of heat only serve to reduce the deformation energy to be applied.

Furthermore, DE 100 47 491 A1 discloses a method for reshaping structures made of aluminum alloys, which reshapes a component to be reshaped by elastic shaping into a predetermined contour under the influence of external force and heating the elastically shaped component to a temperature higher than that for creep shaping and stress relaxation of the alloy required temperature, so that the component is deformed while maintaining the contour. This method is exemplary of methods in which forces first act in a first shaping step in order to achieve a predetermined contour of a component and in a second step a heat treatment is carried out, by means of which the stresses which have arisen are subsequently eliminated.
This two-stage implementation of the shaping process is very complex and requires heating of the entire component in order to remove the existing stresses.

Another method emerges from the prior art, in which according to the publication DE 40 16 097 A1 a blank by metal pressing to one arched molding is formed by the blank clamped on the circumference and arched into a free space. Within this procedure an increased working temperature during the first shaping step Metal pressing used by a two-stage heating of the blank, whereby essentially the entire blank to a first, below working temperature lying temperature is brought and maintained and only partial areas of the blank be brought to working temperature before pressing. The disadvantage here is that the process also necessarily the entire blank first to a working temperature below the later one for metal pressing required working temperature in parts of the blank got to. In addition, the method requires a device for metal pressing depending on the desired temperatures, a two-stage heating device is provided to the two-stage design with different To be able to carry out working temperatures.

The invention is therefore based on the object of a method and a device to propose which cost-effective a precise forming of Molded parts, in particular of container bottoms, allowed, in particular in the areas where the forming process can cause high stresses Tensions can be avoided during the forming process or occur only to a very small extent.

This object is achieved by a method and a device with the in the claim 1 and claim 13 characterized features solved.

Due to the fact that a spherical cap with a definable radius of curvature rotates is held down and at the same time heat is supplied in one, by one Predeterminable diameter of the spherical cap determines a transition area Brim is formed with a predetermined radius, the formation of Tensions in the transition area between the calotte and the brim from the start avoided, so that subsequent annealing is generally dispensed with can. Advantageously, the dome is only in the transition area to reduce the stresses to warm up, so that heating up of the entire component can be dispensed with.

It is also characterized in that a rotating device on which the rotating calotte by at least one stationary heat supply device and one stationary one Forming tool at least in the transition area of the predetermined Diameter can be heated and a brim can be shaped to a predefinable radius a device is formed which advantageously allows the calotte exactly in the specified transition area by means of the heat supply device to form and by an arranged stationary forming tool shape the brim tension-free to a predefinable radius.

Arise from the method according to the invention and the associated device Molded parts, in particular container bottoms, such as bobbin bottoms, arched floors or also hemispherical floors, which are characterized by the fact that they have a Dome and a brim include, the dome has a radius of curvature and the brim has a reduced radius compared to the radius of curvature and a transition area formed on a predeterminable diameter between calotte and brim, as well as by one during manufacture the brim heat treatment carried out in the transition area are designed to be low-tension or ideally tension-free.

In a preferred embodiment of the invention, the transition area between the specifiable radius of curvature of the spherical cap and the area of the shape to be shaped Brim radius formed and warmed.

For this purpose, the at least one heat supply device becomes in the transition area positioned in front of the forming tool in the direction of rotation. Preferably several heat supply devices at the transition area arranged between the calotte and brim, which in a first Version opposite or in a second version be arranged symmetrically on the calotte.

An arrangement of the heat supply device from the outside is preferred the calotte, with an arrangement from the inside respectively from the outside and inside and thus a one-sided respectively bilateral effect on the transition area can be achieved.

According to the invention is arranged by the heat supply device Transition area heated evenly, with a desired forming temperature is selectable for the molded part. The heating of the molded part at the given Temperature leads to a plastic under stress relaxation Forming the calotte in the transition area while shaping the brim. For example, 120 ° C. can be specified as the preferred temperature, here depending on the material other temperatures can also be specified.

It is further preferred that the predeterminable temperature in the transition area between the calotte and the brim by controlling the heat supply device and / or spacing of the heat supply device from the surface the calotte or the brim is adjusted. Eventually by controlling and / or spacing the heat supply device Effective area of the heat supply device depending on the desired the area of the transition area to be heated.

The device according to the invention for carrying out the method comprises a pressing tool for metal pressing a blank, a clamping device for Clamping the blank and a rotating device on which the rotating Calotte by at least one stationary heat supply device and one stationary forming tool is formable.

In a preferred embodiment, the rotation device has a rotation table with a support element and a hold-down. The hold-down preferably engages in the center on an inside of the molded part, in particular the calotte. The pressing tool and the stationary forming tool can be carried out in a common device or in separate devices.

The pressing tool engages on the inside of the calotte, the stationary one Forming tool in a preferred embodiment of the invention, a bead is, which is also on the inside of the calotte and a crimping roller, which on attacks an outside of the calotte.

It is preferred that the calotte on the predeterminable diameter and trained transition area by the heat supply device such It is possible to heat the brim to a predeterminable radius by means of plastic Material forming can be trained.

In a preferred embodiment, the heat supply device has a stand element, a base element, a first and a second fastening element and a media connection and a burner. The first and second fasteners are used to set an angle and a distance of the Brenners opposite the calotte or for adjusting a height of the burner towards the calotte.

In a preferred embodiment, the burner is through the first and / or second The device can be arranged so that the burner flame is at right angles to the transition area hits, with the burner at all times before and during the procedure readjustable, i.e. also at different angles to the surface to be deformed is adjustable in the transition area.

By the process in which the forming of the molded part in the transition area and its heating can be carried out at the same time becomes more advantageous Way at the temperature suitable for the material to be formed, the is preferably only about 120 ° C and in any case below an annealing temperature lies, the formation of tensions in the strongly reshaped transition area avoided from the outset between the calotte and the brim.

By introducing the heat at this relatively low level, for example with two opposing heat sources or with several symmetrically arranged heat sources, when the bottom of the container rotates the flaring area, i.e. the area between the calotte and the brim, very much evenly heated so that optimal material properties for forming and stress relief can be achieved after the forming process.

By arranging a relatively wide burner or a relative one large-scale heating, it is ensured that the mechanical Deformation area the entire material is heated evenly. Thereby the forming forces to be introduced can be reduced in an advantageous manner.

There is also the possibility of a much greater dimensional accuracy than at to achieve the previously known method, so that in an advantageous manner no rework is necessary. In the known annealing of an already deformed one The bottom of the container, e.g. a basket arch floor, must be the bottom reworked with regard to the defined total radius and the edge radius become. By means of the method according to the invention, these method steps can omitted without replacement.

Further preferred embodiments of the invention result from the in the Features mentioned claims.

Figur 1

eine Vorrichtung zum Metalldrücken als Drückwerkzeug eines Formteiles mit zugehörigem Einspannmittel;

Figur 2

das Formteil und eine Wärmezuführungseinrichtung;

Figur 3

das Formteil und eine Vorrichtung zum Umformen als ein Umformwerkzeug;

Figur 4

das Umformwerkzeug mit angeordneten Wärmezuführungseinrichtungen während der Umformung;

Figur 5

das Umformwerkzeug mit Wärmezuführungseinrichtung nach der Umformung und

Figur 6

eine schematische Darstellung des Formteiles, insbesondere ein Korbbodenbogen.

The invention is explained in more detail in an exemplary embodiment with reference to the accompanying drawings. Show it:

Figure 1

a device for metal pressing as a pressing tool of a molded part with associated clamping means;

Figure 2

the molded part and a heat supply device;

Figure 3

the molding and a device for forming as a forming tool;

Figure 4

the forming tool with arranged heat supply devices during the forming;

Figure 5

the forming tool with heat supply device after the forming and

Figure 6

is a schematic representation of the molded part, in particular a basket floor arch.

6 shows schematically a container base 30, in particular a basket arch base. The container bottom 30 has a cap 22 and a brim 20. The calotte 22 has a radius of curvature r _wi and the brim 20 has a radius r _ki . The cap 22 itself is determined by the diameter d _k and the brim 20 and the cap 22 by a nominal diameter d _a . FIG. 6 shows a transition area 32 between brim 20 and cap 22.

The production of a container base 30 according to FIG. 6, in particular with transition areas 32, between the calotte 22 and the brim 20, which at Manufacture of bobbin or arched floors must be trained is an essential object of the invention and is in one embodiment further explained in FIGS. 1 to 5.

FIG. 1 shows a device 10 according to the invention, which holds the container bottom 30, in particular the spherical cap 22, in a clamping means 12, so that a pressing tool 14 is used to deform the blank to form the spherical cap 22. The clamping means 12 can be designed in different ways, it is essential that the clamping means 12 hold the spherical cap 22 rotating in a clamped position. As shown in FIG. 1, the pressing tool 14 permits, in addition to the fixing of the spherical cap 22, rotation within the tools of the clamping means 12. The blank, in particular the spherical cap 22, is given the radius of curvature r _wi by the shaping by means of the pressing tool 14.

Figure 2 shows essentially a heat supply device 18 for training the brim 20 on the - as described in Figure 1 - shaped dome 22. The heat supply device 18 has a stand element 18A, a base element 18B, a media port 18E and a burner 18F on the adjustable in length by a first fastening element 18C and by a second fastener 18D adjustable in height and angle is arranged. The heat supply device 18, in particular the Burner 18F acts on the transition area 32 between the brim 20 and the calotte 22, in the exemplary embodiment from an outer side 38 of the container bottom 30th

Figure 3 shows the device 10, in particular a forming tool 16, which is designed in the form of a bead 42 and from an inside 36 acts on the container bottom 30. The forming tool 16 forms the bead 42 opposite at least one crimping roller 24 from the bottom of the container 30 leads and holds in the area of the brim 20 to be trained. Figure 3 shows in addition to the flanging roller 24 two pressure rollers 24a, which stabilize the workpiece. When the brim 20 is deformed onto the calotte 22, the container bottom rotates 30 in the direction of rotation 46. To carry out the rotation, the Device 10 on a rotary table 40.

The rotary table 40 is shown in FIG. 4 and essentially has one Support element 28 and a hold-down 26. The container bottom 30 is in the forming tool 16 rotated on the rotary table 40 and in Area of the bead 42 and the rollers 24 (not visible in Figure 4) formed.

According to the invention, the brim 20 is formed with a predetermined radius r _ki , while at the same time supplying heat in the transition region 32, starting from the predetermined diameter d _{k of} the calotte 22.

FIG. 4 shows this process of shaping the brim 20, with the heat supply devices 18 symmetrical with respect to the bead 42 and the bead rolls 24 are arranged. The heat supply devices 18 are arranged so that heat supply via the burner 18F is precisely in the transition region 32 between brim 20 and calotte 22 is reached. In the embodiment acts the heat supply device 18 from the outside 38 on the calotte 22 or the brim 20 in the transition area 32, also a supply of heat from the inside 36 or inner side 36 and outer side 38 can be carried out on both sides. Through the supply of heat becomes during the formation of the brim 20 in the transition area 32 stress relaxation is achieved at the same time.

To carry out the process - metal pressing of the blank - by the Pressing tool 14 and - reshaping the calotte 22 - while shaping the Brim 20 with forming tool 16, as shown in FIG. 4, is a control unit 48 with a control system for controlling the entire device 10, consisting of the pressing tool 14 and the forming tool 16. The control device and the control system 48 can also be used for control purposes the heat supply device 18 (not shown) can be used. Another option is to set the temperature only over time.

FIG. 5 shows the container base 30 produced, in particular an arched base, after returning the hold-down 26 of the forming tool 16.

By comparing Figure 5 and Figure 4 it can be seen that the support element 28 is adjustable in height.

The forming tools 18 are also for removing the container bottom 30 can be moved easily via rollers 44, as shown in FIG. 5.

The method and the device are particularly suitable for the production of bobbin-case bases and wicker-arch bases made of aluminum. The production of larger container bottoms usually leads to a decrease in the radii r _{ki of} the brim 20 so that the calotte 22 and brim 20 are produced separately and are later joined together again, in particular by welded connections. This procedure is carried out in particular because tensions can usually be insufficiently avoided in a one-piece production.

The new method and the associated device now allow container bottoms 30 to be produced in one piece with the supply of heat in the transition region 32 and to achieve stress relaxation, in particular also when a decreasing radius r _{ki is} to be formed into a particularly strongly shaped brim 22.

LIST OF REFERENCE NUMBERS

10

contraption

12

chuck

14

spinning tool

16

Forming tool (crimping roller / crimping bulb)

18

Heat supply facility

18A

stand element

18B

base element

18C

first fastener (angle, length)

18D

second fastening element (height)

18E

media connection

18F

burner

20

brim

22

dome

24

flanging

24a

pressure roller

26

down device

28

support element

30

container bottom

32

Transition area

46

Focus

36

inside

38

outside

46

rotary table

42

Bördelbirne

44

role

46

direction of rotation

48

Control system / control unit

r _wi

Dome radius radius

r _ki

Radius brim

d _k

Calotte diameter

d _a

Nominal diameter

Claims (22)

A method in the metal spinning a blank, in particular made of aluminum, into a curved shaped part, in particular the container base, in which the blank is clamped peripherally and in a free space, a cup (22) to a predetermined curvature radius (r _wi) in arched (dished), characterized that the calotte (22) is then held in a rotating manner, with a brim (20) with a predefinable radius (r _ki ) being simultaneously supplied with heat in a transition region (32) determined by a predeterminable diameter (d _k ) of the calotte (22) is formed. A method according to claim 1, characterized in that the transition region (32) between the predefinable radius of curvature (r _wi ) of the calotte (22) and the region of the radius (r _ki ) of the brim (22) is formed and heated. Method according to claims 1 and 2, characterized in that at least one heat supply device (18) is positioned in the transition region (32) in the direction of rotation (46) in front of a forming tool (16). Method according to Claims 1 and 2, characterized in that a plurality of heat supply devices (18) are positioned at the transition region (32) between the cap (22) and the brim (22). Method according to claim 4, characterized in that the heat supply devices (18) are positioned opposite one another on the rotating calotte (22). A method according to claim 4, characterized in that the heat supply devices (18) are positioned symmetrically on the rotating dome (22). Method according to Claims 1 to 6, characterized in that the at least one heat supply device (18) acts on the transition region (32) from an outside (38) and / or an inside (36) of the cap (22). Method according to Claims 1 to 7, characterized in that the at least one heat supply device (18) uniformly heats the transition region (32). A method according to claim 8, characterized in that at a predeterminable temperature with relaxation of tension, the dome (22) is plastically deformed with the brim (22) being formed in the transition region (32). A method according to claim 9, characterized in that the predetermined temperature is approximately 120 ° C. Method according to Claims 1 to 10, characterized in that the predeterminable temperature in the transition region (32) between the calotte (22) and the brim (22) by controlling the at least one heat supply device (18) and / or spacing the heat supply device (18) from the surface of the Calotte (22) or the brim (20) is set. A method according to claim 11, characterized in that an effective area of the heat supply device (18) is set depending on the area of the transition area (32) to be heated. Device for metal pressing a blank, in particular made of aluminum, into a curved molded part, in particular a container bottom, which has at least one clamping means (12) for clamping the blank and a movement-controlled pressing tool (14) for producing a spherical cap with a radius of curvature (r _wi ), characterized by a rotating device (40) on which the rotating calotte (22) can be heated by at least one stationary heat supply device (18) and a stationary forming tool (16) at least in the transition region (32) of a predeterminable diameter (d _k ) and a brim (20 ) can be formed to a predefinable radius (r _ki ). Device according to claim 13, characterized in that the rotation device (46) has a rotation table (40) with a support element (28) and a hold-down device (26), the support element (28) and the hold-down device (26) preferably being in the center (34 ) attack the calotte (22). Device according to claim 13, characterized in that the stationary forming tool (16) has a crimping pear (42) which engages on an inside (36) of the cap (22) and a crimping roller (44) which engages on an outside of the cap (22) , having. Apparatus according to claim 15, characterized in that the cap (22) on the predeterminable diameter (d _k ) and the formed transition area (32) can be heated by the heat supply device (18) in such a way that the brim (20) with a radius (r _ki ) can be formed by plastic material forming. Device according to claims 13 and 16, characterized in that the heat supply device (18) comprises a stand element (18A), a base element (18B), a first and second fastening element (18C, 18D) and a media connection (18E) and a burner (18F) having. Apparatus according to claim 17, characterized in that the first fastening element (18C) has a first device for adjusting an angle and a distance of the burner (18F) relative to the calotte (22). Apparatus according to claim 17, characterized in that the second fastening element (18D) has a second device for adjusting a height of the burner (18F). Apparatus according to claims 16 to 19, characterized in that each arrangement, preferably a right-angled arrangement, of the burner (18F) can be adjusted in relation to the transition region (32) with the aid of the first and / or second device. Apparatus according to claim 13, 16 and 17, characterized in that the heat supply device (18), in particular the burner (18F), can be operated with a combustible medium (gas, oil). Shaped part, in particular a container bottom made of aluminum, characterized by a spherical cap (22) with a radius of curvature (r _wi ) and a brim (20) with a reduced radius (r _ki ), a transition region (d _k ) being formed on a predeterminable diameter (d _k ) 32) between the calotte (22) and the brim (20) is stress-free by a heat treatment carried out during the manufacture of the brim (20).

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