METHOD AND DEVICE FOR COAXIALLY EXTRUDING AN EXTRUDED PRODUCT

Abstract

The invention relates to a method for coaxially extruding an extruded product. Hereby, an extruding device comprises the following: a receiver (7); a first receiver bore (5) which is formed in the receiver (7) and in which a first punch (10) is arranged; a second receiver bore (6) which is formed in the receiver (7) inside the first receiver bore (5) and coaxially therewith and in which a second punch (11) is arranged; and a mold (15) having a mold cavity (14) which is connected to the first and the second receiver bore (5, 6). In the method, the following is provided: arranging a first material billet (8) of a first material (2) in the first receiver bore (5); arranging a second material billet (9) of a second material (3) in the second receiver bore (6); and extruding an extruded product (1) in which the first and the second material (2, 3) are connected in a form-fitting and integrally bonded manner. The extrusion comprises: advancing the first punch (10) in the first receiver bore (5) in such a manner that the first material (2) is pressed into the mold cavity (14) of the mold (15) and thereby shaped; advancing the second punch (11) in the second receiver bore (6) in such a manner that the second material (3) is pressed into the mold cavity (14) of the mold (15) and thereby shaped, the second punch (11) being displaced coaxially with the first punch (10); and connecting the first and the second material in an integrally bonded and form-fitting manner to form an extruded product (1) in the mold (15) in such a manner that the first material (2) surrounds the second material (3) in the extruded product (1). The invention also relates to a device for coaxially extruding an extruded product.

Claims

1. A method for coaxially extruding an extruded product, comprising providing an extruding device comprising a receiver; a first receiver bore which is formed in the receiver and in which a first punch is arranged; and a second receiver bore which is formed in the receiver inside the first receiver bore and coaxially therewith and in which a second punch is arranged; and a mold having a mold cavity which is connected to the first and the second receiver bore; arranging a first material billet of a first material in the first receiver bore; arranging a second material billet of a second material in the second receiver bore; and extruding an extruded product in which the first and the second material are connected in a form-fitting and integrally bonded manner, comprising: advancing the first punch in the first receiver bore in such a manner that the first material is pressed into the mold cavity of the mold and is thereby shaped; advancing the second punch in the second receiver bore in such a manner that the second material is pressed into the mold cavity of the mold and thereby shaped, the second punch thereby being displaced coaxially with respect to the first punch; and connecting the first and the second material in an integrally bonded and form-fitting manner to form an extruded product in the mold in such a manner that the first material surrounds the second material in the extruded product.

2. The method according to claim 1, characterized in that the connecting in a integrally bonded and form-fitting manner in the mold is carried out between the first and the second material.

3. The method according to claim 1, characterized in that the first and the second material are introduced into the mold cavity at different relative speeds.

4. The method according to claim 1, characterized in that a first advance when advancing the first punch in the first receiver bore and a second advance when advancing the second punch in the second receiver bore are set independently of one another.

5. The method according to claim 1, characterized in that the advancing of the first punch in the first receiver bore is carried out at a first advance speed and the advancing of the second punch in the second receiver bore is carried out at a second advance speed which is different from the first advance speed.

6. The method according to claim 1, characterized in that the first punch, when moving in the first receiver bore, is driven by means of a first actuator and the second punch, when moving in the second receiver bore, is driven by means of a second actuator which is formed separately from the first actuator and is controllable.

7. The method according to claim 1, characterized in that a material which is different from the first material is used as the second material.

8. The method according to claim 1, characterized in that the same material is used for the first and the second material.

9. The method according to claim 1, characterized in that an extruded profile is produced as the extruded product.

10. The method according to claim 1, characterized in that an extruding device is provided in which the second receiver bore is arranged in an inner cavity of the first punch.

11. The method according to claim 10, characterized in that an extruding device is provided in which the second receiver bore is formed by the inner cavity of the first punch and the second punch is received in the inner cavity in a form-fitting manner.

12. The method according to claim 10, characterized in that an extruding device is provided in which the second receiver bore formed by means of a sleeve component which is arranged in the inner cavity of the first punch, and the second punch is received in the inner cavity of the sleeve component in a form-fitting manner.

13. A device for coaxially extruding an extruded product, comprising a receiver; a first receiver bore which is formed in the receiver and in which a first punch is arranged; a second receiver bore which is formed in the receiver inside the first receiver bore and coaxially therewith and in which a second punch is arranged; and a mold having a mold cavity which is connected to the first and the second receiver bore in such a manner that during extrusion by means of advancing the first punch in the first receiver bore and advancing the second punch coaxially with the first punch in the second receiver bore, a first material of a first material billet from the first receiver bore and a second material of a second material billet from the second receiver bore can be introduced into the mold cavity for producing an extruded product in which the first and the second material are connected in a form-fitting and integrally bonded manner.

Description

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0037] In the following, further exemplary embodiments are explained with reference to figures of a drawing. In the figures:

[0038] FIG. 1 shows a schematic illustration of a device for producing an extruded product;

[0039] FIG. 2 shows a perspective illustration of a receiver for an extruding device in elevation, in which a first and a second punch are arranged in a coaxial arrangement corresponding to a first and a second receiver bore;

[0040] FIG. 3 shows a schematic illustration of a cross-section of an arrangement with two punches for pressing material billets of different lengths; and

[0041] FIG. 4 shows a schematic illustration of a cross-section of a further arrangement with two punches for pressing material billets of different lengths.

[0042] FIG. 1 shows a schematic illustration of a cross-section of a device for producing an extruded product 1 by means of coaxial extrusion. In the extruded product 1, a first material 2 and a second material 3 are joined together along a circumferential join or joining seam 4 in a form-fitting and integrally bonded manner by means of extrusion in such a manner that the second material 3 is surrounded axially circumferentially by the first material 2. The extruded product 1 can be an extruded profile.

[0043] The formulations extruded profile and extruded product in the meanings used herein comprise all profile geometries that can be produced by means of the extrusion process. This includes, for example, solid profiles as well as hollow profiles and semi hollow profiles in any geometries. For example, extruded sheets as well as tubes, window profiles or round bars are known as extruded profiles.

[0044] For producing the extruded product 1, a first material billet 8 made of the first material 2 and a second material billet 9 made of the second material 3 are arranged in a first and a second receiver bore 5, 6 of a receiver 7. The first and the second receiver bore 5, 6 provide a respective channel with a cylindrical shape, which can have a round, angular or oval cross-section. A first and a second punch 10, 11 are arranged in the receiver bores 5, 6, each of which can be displaced in the axial direction and in this respect coaxially with respect to one another in the associated receiver bore 5, 6.

[0045] The first punch 10 is designed as a hollow component and surrounds the second receiver bore 6 when it is inserted into the first receiver bore. A wall 6a which delimits the second receiver bore 6 and the inner side of which faces the second receiver bore 6 can be designed as a separate wall between the first and the second receiver bore 5, 6. Alternatively, the second receiver bore 6 can be formed by means of a cavity in the first punch 10. In this case, the second punch 11 can slide or slip within the cavity of the first punch 10 during the advance.

[0046] A first and a second actuator 12, 13 are associated with the first and the second punch 10, 11, which actuators are configured to apply force to the respective punch 10, 11 so that the punches 10, 11 perform a coaxial advance movement in the direction of a mold cavity 14 of a mold 15 in order to introduce the first and the second material 2, 3 into the mold cavity 14. For this purpose, the first and the second receiver bore 5, 6 are in communication with the mold cavity 14 in such a manner that the material of the first and the second material billet 8, 9 is introduced into the mold cavity 14 and is shaped in the process. The pressurization results in the fact that the join 4 between the first and second materials 2, 3 is formed in the mold cavity 14.

[0047] According to the schematic illustration in FIG. 1, the first actuator 12 is shown in two parts or pieces. However, it can be a single first actuator.

[0048] By means of the first and the second actuator 12, 13, the first and the second punch 10, 11 can perform advance movements decoupled from each other during extrusion. In particular, the first and the second punch 10, 11 can move at different speeds during advance. By means of the independent setting of the two advance movements, it is possible to set different flow velocities for the transition of the first and the second material 2, 3 into the mold cavity 14. The first and the second material 2, 3, which form an outer and an inner material, can be, for example, different metallic materials, but the use of the same metallic materials for the two material billet 8, 9 can also be provided. The extruded product 1 produced can be an extruded profile.

[0049] Further exemplary embodiments are explained below with reference to FIGS. 2 to 4. For identical features, the same reference signs as in FIG. 1 are used.

[0050] FIG. 2 shows a schematic illustration of an arrangement for an extruding device for coaxial extrusion, in which the first and the second punch 10, 11 are arranged in the first and the second receiver bore 5, 6. While the first punch 10 is designed as a hollow punch, the second punch 11 is a solid punch. In the first punch 10, the second receiver bore 6 for the second punch 11 is formed such that an outer surface of the second punch 11 and an inner surface of the first punch 10 are arranged opposite each other and in contact with each other

[0051] A form-fitting seal can be achieved by means of a so-called press plate (not shown) positioned between the punch 10, 11 and the material billets 8, 9. This press plate is used both fixedin the sense of temporarily structurally connected to each other, but interchangeableand loose.

[0052] FIG. 3 shows a schematic illustration of elements of an arrangement for an extruding device for coaxial extrusion, in which the first and second material billet 8, 9 are formed with different billet lengths. In the embodiment shown in FIG. 3, the first material billet 8 is shorter than the second material billet 9. In another embodiment shown in FIG. 4, the length ratio of the first and second material billet 8, 9 is reversed. The illustrations in FIGS. 3 and 4 then show, from left to right, the increasing advance of the first and the second punch 11 to produce the extruded product 1.

[0053] In the following, aspects relating to further embodiments are explained.

[0054] The method for hybrid extrusion by means of the multi-punch system uses, for example, the dual-punch design explained above with the multi-hole recipient or receiver 7 having the at least two bores for the receiver bores 5, 6 in a coaxial arrangement and the corresponding number of individually movable and controllable punches 10, 11. The mold 15 (extrusion die) is fed by the separate material streams. The mold cavity 14 provides a welding chamber to join the partial strands of the materials by the action of pressure and temperature.

[0055] The punches 10, 11 move the pressed material in the material billets 8, 9 either at the same speed or at different speeds in the direction of the mold 15, depending on the individual volume flows. The individual receiver bores 5, 6 and corresponding press plates do not have to have the same diameters.

[0056] In the method, the material billets 8, 9 are moved through the receiver bores 5, 6 in the direction of the mold 15 (die) in a manner comparable with direct extrusion. In doing so, due to the relative movement between the inner walls of the receiver bores 5, 6 and the outer surfaces of the material billets 8, 9, large parts of the oxides and impurities of the extrusion billets can already be retained. The material streams feeding the mold cavity 14 are already sheared and contain only a small amount of impurities. Material streams with virtually clean metallic surfaces enter the mold cavity 14. These are joined in mold cavity 14 and exit the mold 15 through the press channel as a composite strand (extruded product 1).

[0057] Depending on the individual extrusion ratios provided for the individual material streams, the punch speeds can be adapted so that, in accordance with the product specification, defined volume fractions of the individual composite partners in the product can be implemented. At the same time, a defined positioning of the boundary layer is achieved by specifying the volume fractions.

[0058] In the case of pressing at the same speed of both punches 10, 11 and a constant billet length, a profile is pressed in which the composite materials are pressed out symmetrically next to each other in the same ratio. By means of a selectively adjustable temperature difference between the two material billets 5, 6, composite flat profiles can be produced from separate containers both from material pairs with small and with large differences in forming resistance.

[0059] In the case that both materials 2, 3 are to be present in different volume fractions in the extruded product 1, this results in different extrusion ratios for each material (hybrid partner) if the container geometry is maintained. This is taken into account by steering the billet length in conjunction with two punches moving at different speeds. For this purpose, it is necessary for both punches 10, 11 to be displacement-controlled. In order to be able to control the punches 10, 11 autonomously, the extrusion press can have a separate hydraulic system for the movement of the punches 10, 11.

[0060] In the embodiments described, one or more of the following advantages over known extrusion methods can be achieved: Thermal and tribological decoupling of the material partners; adjustability of different billet temperatures; separate control of the flow rates of the material partners; individual adaptation of the required process variables; and targeted steering of the material flows for variable volume ratios (load/function-adapted cross-sections).

[0061] The method enables the production of metallic material composites within a single massive forming step. By using separately controllable punches and the possibility of implementing different receiver bores (punch receptacles), the flow of the material partners with significantly different flow stresses can be set in such a manner that a defined material arrangement (volume ratio of the material partners or wall thickness of the material partners, formation of the boundary layer) can be set over the complete profile length of the extruded product 1.

[0062] The features disclosed in the above description, the claims and the drawing can be of importance both individually and in any combination for the implementation of the various embodiments.