Extrusion press for producing flat sheets

Abstract

An extrusion press for producing flat metal sheets from hollow sections made of magnesium or magnesium alloys, comprising a mandrel head protruding into the die opening of an extrusion tool, wherein the mandrel head (7) of the mandrel (5) is disposed so as to protrude from the outside into the opening of the die, and the mandrel head (7) has a conical design.

Claims

1. An extrusion press for producing flat metal sheets from hollow sections made of magnesium or magnesium alloys, comprising: a frame; a container configured to receive a round billet; a die having a cylindrical inner surface; and a cylindrical mandrel having a conical mandrel head with a pointed tip at one end and an end region opposite the conical mandrel head, the mandrel being disposed so as to be held at its end region by the frame with the mandrel protruding from outside through an opening of the die such that the conical mandrel head is arranged entirely inside the container axially spaced inwardly of the die, wherein a flat metal sheet is formed by pressing the round billet through an elongated hollow cylindrical gap formed between the cylindrical inner surface of the die and a cylindrical portion of the mandrel, axially spaced behind the conical mandrel head, to form a tubular hollow section and subsequently by forming the tubular hollow section into the flat metal sheet, and wherein material of the round billet flows along the conical mandrel head towards the gap.

2. The extrusion press according to claim 1, wherein the container and the mandrel are separately from one another attached to the frame.

3. The extrusion press according to claim 1, wherein the end region of the mandrel includes a wing-shaped expanding edge which faces the die.

4. The extrusion press according to claim 1, wherein the die and the mandrel are coated with a ceramic material.

5. The extrusion press according to claim 1, wherein the inner cylindrical surface of the die has a constant diameter along an entire length of the die.

6. The extrusion press according to claim 1, wherein the hollow cylindrical gap has a constant diameter along an entire length of the die.

Description

(1) Proceeding from the prior art, it was the object of the inventor to provide an extrusion press for producing flat metal sheets from hollow sections made of magnesium or magnesium alloys using a mandrel head protruding into the die opening of an extrusion die, which eliminates the aforementioned disadvantages.

(2) This object is achieved by an extrusion press for producing flat metal sheets from hollow sections made of magnesium or magnesium alloys, which has a frame, a container configured to receive a round billet, a die, and a mandrel. The mandrel has a conical mandrel head at one end and an end region opposite the mandrel head. The mandrel is disposed so as to be held at its end region by the frame with the mandrel head protruding from the outside into an opening of the die. A flat metal sheet is formed by pressing a round billet through a gap formed between the die and the mandrel to form a tubular hollow section and subsequently forming the tubular hollow section into a flat metal sheet. When in use, material of the round billet flows along the conical mandrel head towards the gap.

(3) According to the invention, the round billet is pressed by way of the stem against the tip of the mandrel protruding from the outside into the die. The material flow of the round billet is guided along the conical tip of the mandrel in the direction of the gap between the mandrel and the die.

(4) This has the advantage that it is no longer necessary for the material flow to be divided by the bridge parts and subsequently re-united in the fusing chamber. This avoids imperfections which cause long profile sections to have to be removed as waste from the developing strand, and the economic efficiency is considerably improved. Furthermore, the open two-part configuration of the die and mandrel allow these to have a simple design, and the surfaces thereof can be provided with a coating made of ceramic material to reduce friction.

(5) The invention will be described in more detail based on one exemplary embodiment. The associated FIG. 1 shows a section of the extrusion press according to the invention. The extrusion press for the direct extrusion of hollow sections, which thereafter are formed to obtain flat metal sheets, comprises a stem 1 on a pressing cylinder, the stem extending in the longitudinal axis of a borehole extending through a container 10. The container 10 accommodates the round billet 2.

(6) The die 3, which determines the outer contour of the hollow section 11, is mounted at the end of the container 10 in a die holder 4. The mandrel head 7 of the mandrel 5 is disposed so as to protrude from the outside into the opening of the die, and more particularly with the mandrel head 7 thereof pointing in the direction of the container 10. As shown, the cylindrical mandrel 5 has a conical mandrel head 7 with a pointed tip. The mandrel 5 protrudes from the outside through an opening of the die 3 such that the conical mandrel head 7 is arranged entirely inside the container 10 axially spaced inwardly of the die 3. The mandrel 5 determines the inner contour of the hollow section 11 and has a conical design. The mandrel 5 can be provided with a cooling or heating device.

(7) On the side facing away from the mandrel head 7, the mandrel 5 has an end region 9, by which it is attached to the frame of the extrusion press. The end region 9 of the mandrel 5 includes a expanding edge 8, which has a wing-shaped design, on the side facing the die 3. A cutting device 6, preferably a laser, is disposed between the expanding edge 8 and the die 3, preferably in the vicinity of the same, which severs the hollow section 11 along the peripheral surface thereof after exiting the die 3.

(8) So as to produce the hollow section 11, and ultimately the flat metal sheet, the container 10 is loaded with the round billet 2, which is pressed in the direction of the die 3 by way of the stem 1. After the round billet 2 impinges on the mandrel head 7, the material flow of the round billet 2 is guided along the conical tip of the mandrel head 7, in the direction of the gap between the mandrel 5 and the die 3, and shaped into the hollow section 11.

(9) After the hollow section 11 exits the die 3, the hollow section is severed along the peripheral surface thereof and formed into a flat metal sheet on impingement on the expanding edge 8.

LIST OF REFERENCE NUMERALS

(10) 1stem 2round billet 3die 4die holder 5mandrel 6cutting device 7mandrel head 8expanding edge 9end region 10container 11hollow section