Patent Application
20210291246
The disclosure relates to an apparatus for producing metal sheets from round or approximately round thin-walled extruded profiles or hollow chamber plates, which are in particular made of magnesium or magnesium alloys, by an extruder. Plate-shaped extruded profiles with inner webs connected to opposite profile walls and at least two mutually adjacent hollow chambers featuring a common inner web, which are also known as web plates or double-web plates, are referred to as hollow chamber plates.
The production of sheet metal by casting a liquid alloy between two rollers and then numerous rolling and heat treatment processes is generally known. Due to the large number of rolling passes from coarse to thin sheet, this process is highly cost-intensive. These steps are necessary to achieve a deformable wrought structure from a cast structure. The high number of rolling passes is cost-intensive.
DE 43 33 500 C2 discloses a method for producing a sheet with a stepped cross-section and a solid profile with different wall thicknesses, with which a semi-finished product is initially produced, whose cross-section is similar to the cross-section of the sheet in the thickness direction, and with which a sheet is rolled from the semi-finished product, wherein, for the production of the semi-finished product, a hollow profile with a wall thickness profile distributed around the circumference and corresponding to the desired wall thickness profile of the semi-finished product is extruded, and in so doing the hollow profile is cut along a surface line and deformed into the semi-finished product. In addition, two complementary profiles are placed one on top of the other, wherein at least one of the profiled contact sides of the complementary profiles is provided with a release agent, and the two complementary profiles are rolled out simultaneously with cylindrical, that is, non-stepped rollers. Prior to rolling, the two complementary profiles are separated on two opposite surface lines.
This method is used to produce two parts at a time. The production process is discontinuous, and only relatively narrow parts can be produced. A further disadvantage is that the production process is relatively costly due to the manufacture of the semi-finished product with two different wall thicknesses and a stepped roller arrangement.
DE 10 2008 048 A1 describes a method for producing sheet metal parts and a device for carrying out the method. The method comprises the steps of—extruding or continuous casting of a tubular body, —cutting of the tubular body open in its longitudinal direction, —expanding of the tubular body to form a flat body, —producing of the flat body to form the component according to drawing by means of known production technologies. The device essentially consists of a chain of a melting unit, a continuous casting or extrusion unit, a longitudinal cutting device, a roll stand, one or more deforming units.
From DE 10 2007 002 322 A1, a method for the production of sheet metal or sheet metal parts made of light metal, preferably magnesium, is known, wherein, in one or more preceding method steps, an extruded profile is produced in an open structure or a closed structure with subsequent slitting to form an open structure, and this is then subjected in one or more steps to straightening rolling and straightening bending over several rolling and bending stages.
GB 2469 549 A describes a method for producing a support structure, preferably a support structure for a vehicle seat with at least one seat shell for the seat part and/or the backrest of the vehicle seat, with the method steps of producing a metallic semi-finished product and deforming it into an essentially flat sheet metal, separating a sheet metal part from the sheet metal and deforming the sheet metal part, wherein the production of the metallic semi-finished product is effected by means of extrusion.
U.S. Pat. No. 2,681,764 A describes a device for extruding wide sheet metal comprising a die element with a base section in the form of an elongated U-shaped slit for producing a U-shaped profile, which is subsequently flattened.
U.S. Pat. No. 1,133,903 A describes the transformation of metal tubes into flat strips by cutting the tubes lengthwise and expanding them by means of a double flying blade and subsequent rolling.
U.S. Pat. No. 3,002,255 A describes a method for producing continuous metal strips and the like. Production takes place by extruding a plurality of blocks successively in a form other than flat, flattening them step-by-step after extrusion and keeping the form under tension during the flattening step, and winding up the previously flattened strips during each extrusion step.
GB 556 061 describes an improvement in the production of iron and steel sheet metal from tubes that are continuously produced by casting. After leaving the die of the extruder, they are cut open lengthwise and expanded and smoothed by means of forming rollers.
U.S. Pat. No. 5,829,298 A describes a method and a device for the continuous production of metal strips, wherein a workpiece is fed to a punch to form a tube with a circular cross-section and a slit formed therein, and the tube is opened and flattened by outward bending in opposite directions in the slit area.
EP 2996825 B1 describes a method and apparatus for producing metal sheets from extruded profiles of small thickness, in particular of magnesium or magnesium alloys, wherein the extruded profile exiting the extrusion die is formed into a metal sheet. The facility consists of an extruder with a die producing the extruded profile and a deformation unit following the die, wherein the deformation unit consists of a cutting unit for cutting the extruded profile according to the length of the metal sheet to be produced, a bending unit for bending the profile into a U-shape and a coiling unit for coiling the U-shaped profile into a metal sheet.
An apparatus for the production of metal sheets from round or approximately round thin-walled extruded profiles or hollow chamber plates, in particular made of magnesium or magnesium alloys is disclosed. The preferably open extruded profile exiting an extrusion die is expanded to form a metal sheet or a hollow chamber plate, and the expansion process is decoupled from the extrusion process.
The open extruded profile emerging from the extrusion die of an extruder is cut off according to the length of the metal sheet or hollow chamber plate to be produced. The longitudinal gap of the open extruded profile is widened, preferably to an approximately U-shaped profile, and then transferred to an expansion unit, in which it is expanded to form a flat sheet or plate and then placed in a stacking unit. The apparatus has at least one, preferably two, expansion units arranged parallel to the direction of extrusion. Metal sheets with a thickness <5.0 mm, preferably with a thickness in the range <2.5 mm, in particular from 1.0 to 1.5 mm, or hollow chamber plates are produced.
In a first step, the extruded profile emerging from the die is cut off according to the length of the metal sheet to be produced and, in a second step, the longitudinal gap of the open extruded profile is widened, preferably to an approximately U-shaped profile. In the subsequent third step, the U-shaped profile is brought into an expansion unit and gripped by clamping devices on the longitudinal sides of the U-shaped profile and deformed into a metal sheet or hollow chamber plate by means of the clamping devices moving outwards.
The open extrusion profile can also be deformed to form a metal sheet or a hollow chamber plate alternatively by at least one pair of rollers, which are inserted into the open extrusion profile and by moving the individual rollers in the direction of the longitudinal edge areas.
Another possibility for the design of the expansion unit is that it consists of a combination of gripping elements and two movable rollers that can be inserted into the U-shaped profile. In order to protect the surface of the metal sheet to be produced, the rolls can be provided with a heat-resistant elastic surface coating. The rollers used for this are designed in such a manner that they do not cause any surface damage.
One possibility for expanding an open extrusion profile into a metal sheet or a flat hollow chamber plate includes forming the open extrusion profile into a metal sheet or a hollow chamber plate by means of a 3-roller unit.
The 3-roller unit of the expansion unit includes two upper rollers arranged parallel to each other and a lower roller adjustable in the longitudinal direction of the upper rollers. A feed unit, preferably consisting of a pair of rollers, is provided to transport the profile through the 3-roller unit.
Another possibility for expanding the open extruded profile is to insert the profile with its opening facing upwards into the expansion unit and then retract the 3-roller unit, wherein the upper rollers are provided inside the profile and the lower roller is provided outside the profile. By moving the 3-roller unit to the left and right, the profile is expanded to form a metal sheet or a hollow chamber plate.
The deforming into sheet metal or hollow chamber plate is preferably carried out in a temperature range above 200° C. and in a dry, preferably inert, atmosphere.
The apparatus for producing a metal sheet from an extruded profile consists essentially of a furnace for heating the extrusion billets to extrusion temperature, an extruder with a die for extruding a hollow profile open in the longitudinal direction, a separating device for cutting the extruded profile to length and a bending unit. At least one expansion unit and a subsequent stacking unit are provided parallel to such bending unit.
To precisely size the expanded metal sheets or hollow chamber plates, a sizing and squeezing unit can be provided between the expansion unit and the stacking unit, in which the metal sheet is hot squeezed, that is, smoothed, between two heated embossing plates. The sizing and squeezing unit can be designed in the form of a simple hydraulic press.
The metal sheets are preferably placed in the stacking unit by a robot, which uses suction cups to pick up the metal sheet or hollow chamber plates from either the expanding or the sizing and squeezing unit and places them in the stacking unit.
Machining or non-machining devices can be used as separating devices to cut the extruded profile to length in accordance with the length of the metal sheet. Saws, for example, can be used as machining separating devices, while circulating jet nozzles, laser separating devices or wedge or pinch cutting are used as non-machining separating devices.
The invention shall be described in more detail by reference to an exemplary embodiment and the drawings.
All devices of the apparatus are interlinked. The transfer of the U-shaped profile 7 to the expansion unit 3 and of the expanded profile 7 to the stacking unit 5 and, if necessary, to the interposed sizing and squeezing unit is carried out by handling devices, preferably by industrial robots. For this purpose, the handling devices are equipped with mechanical or pneumatic gripping systems.
After a predetermined length of the profile 7 has been pressed out, the extruder is stopped and the profile 7 is cut to length by the separating device 6 according to the length of the metal sheet to be produced.
An additional variant of cutting to length the hollow profile 7 from the extrusion is shown in
Wedge or pinch cutting has the advantage that, being a chipless cutting process, it does not produce any chips or splinters that would otherwise have to be removed from the surface in the cutting area.
After the profile 7 has been cut to length, it is released from the extrusion unit. The profile 7, which is slotted in the longitudinal direction and placed on the angle rails 11 of the bending unit 4, is moved out of the area of the separating device 6. Subsequently, the profile 7 is bent open into a U-shape (
The U-shaped bent profile 7 is grasped by a handling device (not shown in detail) and transferred to the expansion unit 3. Here, the U-shaped profile 7 is fully expanded. For this purpose, the profile 7 is inserted with its longitudinal sides into the rotatably mounted clamping units 16, wherein the profile 7 is deformed into a flat sheet by moving the clamping units 16 apart.
The U-shaped bent profile 7 inserted in the clamping units 14 of the expansion unit 3 is clamped by the clamping rail 18 in the clamping unit 16. Clamping is achieved by applying pressure to the clamping rail 18. For this purpose, at least two hydraulic cylinders 17 are arranged along the outer side of the clamping rails over their length.
The U-shaped profile 7 is expanded to form a flat metal sheet 19 (
If the metal sheets 19 still show unevenness after the expanding process, they are transferred to a sizing and squeezing unit prior to being placed in the stacking unit 5. For this purpose, the metal sheet 19 is clamped on the transverse side and moved into the sizing and squeezing station by a linear drive. In the sizing and squeezing unit, the metal sheet 19 is hot squeezed, which removes any unevenness that may exist.
The sizing and squeezing unit is formed by two heated embossing plates 24 that can be moved towards each other. The embossing plates 24 can be opened and closed by a simple hydraulic press.
After the sizing and squeezing process, the metal sheet is picked up by a handling device with a suction pad and placed in the stacking unit 5.
In a further exemplary embodiment, the production of hollow chamber plates 20 is described.
The extruded profile 7 is designed in such a manner that it assumes the shape of a flat hollow chamber plate 20 after expansion. The extruded profile 7 is designed in such a manner that the sections of the lower side 22 and the upper side 21 between the inner webs 23 have the same length. Consequently, the sections of the lower side 22 between the inner webs 23 are formed in an inwardly convex curved manner during extrusion. After the expansion process, the sections between the inner webs 23 on the lower side 22 and the upper side 21 have the same length.
The extruded profile 7 emerging from the die of the extruder 1 in a first step is cut off according to the hollow chamber plate 20 to be produced. As the separating device 6, a machining cutting device, for example a saw, is preferably used here. This is connected to an extraction system for the chips.
Subsequently, the extruded profile 7 is bent up into a U-shaped profile 7 by means of the bending unit 4 and is taken further into an expansion unit 3. The bending up to a U-shaped profile 7 takes place by moving the angle rails 11 of the bending unit 4 apart.
In the expansion unit 3, the U-shaped profile 7 is expanded to form a flat hollow chamber plate 20. After the expansion process, the hollow chamber plate 20 is placed in a sizing and squeezing unit.
The sizing and squeezing unit is shown schematically in
After the longitudinal side (front edge) of the profile 7 has been gripped by the pair of rollers 28, it is pushed in the direction of the 3-roller unit. If the front edge of the profile 7 reaches the second upper roller 26, the lower roller 27 is moved in the direction of the upper rollers 26. When the profile 7 is pushed further through the 3-roller unit 25, it is formed into a flat metal sheet 19, that is, it is expanded from the U-shaped profile 7 into the metal sheet 19. This can be followed by a sizing and squeezing step, or the metal sheet 19 can be placed directly in the stacking unit 5.
All parts of the apparatus that come into contact with the U-shaped profile 7 or the metal sheet 19 or the hollow chamber plate 20 are provided with a coating, preferably with a ceramic material, or are made of a magnesium-compatible material, in order to prevent direct contact with a ferrous material.
The apparatus for producing metal sheets or hollow chamber plates from extruded profiles has the advantage that the expansion process to form a flat sheet or hollow chamber plate is decoupled from the extrusion process, by which the number of cycles for the production can be substantially increased.
The extrusion of magnesium sheet also has the advantage of being able to produce very thin sheet thicknesses in a single process step and thus represents an alternative to rolling or casting-rolling.
Not only can very thin sheet thicknesses be realized here, but also very wide sheets can be produced by extruding hollow profiles, for example tubes. The extrusion process can also be used to produce very wide hollow chamber plates. The width results from the circumference of the extruded profiles in accordance with the formula u=d*n. For example, for a tube diameter of 300 mm, a sheet with a width of approximately 942 mm can be produced.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2018 004 387.9 | Jun 2018 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2019/000150 | 5/24/2019 | WO | 00 |
