DE102011051943A1 - Forming tool and method for producing molded components from metal blanks - Google Patents

Abstract

The invention relates to a forming tool and a method for producing molded components from metal blanks, preferably from light metal blanks. The heated to a forming temperature metal plate is formed in a forming tool 1A between a heated mold body 5 of a tool upper part 3 and a heated mold body 4 of a tool lower part 2 to the mold component. At least one shaped body 4, 5 is arranged in a bearing 22, wherein the bearing 22 is designed such that thermal expansions of the shaped body 4, 5 are made possible during the heating process.

Description

The invention relates to a forming tool and a method for producing molded components made of metal plates, preferably of light metal.

Tempered forming processes increase the cut-off ratio in metal blanks, especially in light metal blanks, such as aluminum blanks. In addition, on the one hand there is a substitution potential for light metal compared to steel components. On the other hand, a reduction in weight can be achieved by reducing the wall thicknesses and the assembly effort can be reduced by avoiding multi-part components.

The EP 1 601 478 B1 describes the deep drawing of heated aluminum blanks in an at least partially heated tool at 150 ° C to 350 ° C in the presence of a compatible with the subsequent operations lubricant.

The DE 10 2006 046 305 A1 discloses an apparatus for at least partially forming sheets beyond the forming limits.

The DE 101 62 437 A1 describes a forming tool with a shaping engraving for the manufacture of workpieces of metallic materials, in particular aluminum. The forming tool is divided into engraving segments with engraving surfaces for setting different temperature fields.

By the CH 657 548 A5 includes a forming tool for isothermal forming of metals in the art. This consists of an inner molded body, referred to there as a die body, an immediately surrounding, annularly arranged, electrically and thermally insulating ceramic body in which an inductive heating coil is embedded, a radial prestress generating pressing body and arranged between the ceramic body and the compact annular Component which serves the magnetic field control and can be designed as an annular electrical conductor for shielding or as a magnetic segment or magnetic ring for conducting the magnetic field.

The moldings of hot or warm forging tools are exposed to high thermal and mechanical stresses during operation. This applies in particular to the active surfaces of the molded bodies coming into contact with the metal plates to be formed.

Another problem with hot or warm forging results from the thermal expansion of the various materials, on the one hand the materials of the metal plates to be formed and on the other hand, the materials of the forming tools. As a result of the thermal expansion, this can adversely affect the forming process and the molded components to be produced.

In addition, there already exists a different material expansion between the various components when heating tool parts to operating temperature, which also results from the necessity of decoupling hot components which are in contact with the components to be molded, in particular heat-sensitive components.

The invention aims at improving the efficiency and process reliability of component production with tempered tools.

The invention is therefore, starting from the prior art, based on the object to show a system engineering and application technology improved forming device and a method for the production of molded parts of metal blanks with improved efficiency and process reliability in component manufacturing.

The objective part of the object is achieved by a forming tool according to claim 1.

The solution of the procedural part of the task shows claim 11.

Advantageous embodiments and modifications of the invention are the subject of the dependent claims.

The forming tool for the production of molded components made of metal plates has a tool upper part and a lower tool part. The upper tool part and the lower tool part comprise heatable molded bodies, between which the metal plates are formed. At least one shaped body in the upper tool part and / or in the lower tool part is arranged in a bearing, wherein the bearing is designed such that thermal expansions of the shaped body are made possible during the heating phase.

The invention aims at the core to an isothermal deformation under elevated temperature. In this case, a uniform temperature of the tool and workpiece or metal plate is desired as a function of location and time for the entire deformation process. In the context of the invention, isotherm is to be understood as meaning a temperature with the accuracy of +/- 25 ° C. This requires that the tool or the moldings are heated. Accordingly, a heating device is provided, by means of which the shaped bodies are heated to the required forming temperature. To ensure the isothermal deformation, the forming tool or the shaped body is heated homogeneously and kept at a preselected forming temperature during series production. This is done by suitable geometric arrangement of the heater, in particular a resistance heating elements, for example cartridge heaters, with appropriate power and by division or arrangement of a number of heating elements in a control loop, which are determined by a heat distribution simulation. Alternatively it can be provided to perform a control based on the detection of the component temperature during the forming process. The thermal expansions of the moldings and / or the metal blanks to be formed are made possible in or by the storage according to the invention. For this purpose, both the expansion of the tool steel of the moldings and the metal plate to be formed are taken into account in the geometric design of the moldings. In this context, it is particularly important to understand the coefficients of thermal expansion of the materials used for the shaped article on the one side and the molded component on the other side. In practice, it can be assumed that thermal expansion on the order of up to several millimeters must be possible.

The forming tool according to the invention and the method according to the invention increase the cost-effectiveness and process reliability of the component production with tempered tools. In addition, only then the applicability and durability is ensured for a series operation. The invention enables isothermal hot or warm forging with short cycle times. Problems from the thermal expansion difference between tool steel of the moldings and the material of the metal plate to be formed are largely eliminated. In addition, the use of materials can be reduced by reducing the costs of further processing, even with demanding geometries.

Preferably, the storage comprises three, in particular at least four staggered bearings. In particular, the four bearings on a pitch circle are offset by 90 ° to each other. Particularly advantageously, the bearing or each bearing has a guided in an expansion groove sliding block.

On the upper mold body and on the lower mold body and / or on a hold-down guide segments are provided, via which the upper mold body and the lower mold body and / or the hold-down during the forming process are relative to each other position-oriented.

The moldings can be massive, so-called monobloc bodies. In the context of the invention, the shaped bodies can also be advantageously segmented and composed of individual shaped body segments. This improves the assembly and also allows easy interchangeability of the moldings or individual molded body segments. Within the scope of the invention, at least one shaped body segment can also be arranged to be vertically displaceable relative to adjacent shaped body segments.

For controlling the temperature of the molded body, a heating device is provided. The tempering can be carried out preferably by an electrical resistance heating, for example via cartridge heaters, or inductively by means of an inductive heating coil. The heating device may be in contact with a surface of the molded body as a separate tool component on the outside. The heater or components thereof may also be integrated into the moldings.

The thermoforming of steel blanks, in particular of high-strength steels, is carried out in a temperature range of 900 ° C to 1250 ° C.

The hot forging of sheet steel plates takes place at 650 ° C to 900 ° C.

The warm forging of corrugated metal boards is carried out at a temperature between 150 ° C and 550 ° C depending on the material.

High-strength aluminum alloys of the 7xxx series or magnesium alloys only have a significant deformability at elevated temperatures, which requires tempered tools. It has been found that alloys of the 7xxx series are sufficiently ductile at higher temperatures so that they can be hot-formed in a forming tool. The storage according to the invention contributes significantly to the economy and process reliability in the production of components made of high-strength aluminum alloys.

Within the scope of the invention, a temperature between 150 ° C. and 350 ° C., preferably a temperature between 200 ° C. and 300 ° C., is considered to be advantageous in the case of an aluminum alloy of the 5xxx series. For this purpose, the forming tool has a heating device by means of which the temperature of the mold jaws to a temperature of 150 ° C to 350 ° C, preferably between 200 ° C and 300 ° C.

The metal plate is preferably made of light metal, in particular of aluminum or an aluminum alloy, preferably of a naturally hard aluminum alloy of the 5xxx series. Such Materials of the Al-Mg group (5xxxer) are, for example, naturally hard aluminum alloys Al-Mg3 ( EN-AW 5754 ) or Al-Mg4.5Mn ( EN-AW 5083 ). By the use of light metal, in particular aluminum or an aluminum alloy and magnesium or a magnesium alloy lightweight construction is taken into account.

In the context of the invention is - as already stated - an isothermal hot or warm forging desired. The invention enables the production of molded parts with uninterrupted fiber flow and tight dimensional tolerances. There are high to very high degrees of deformation feasible. At the same time, the invention enables low forming times and avoidance of concatenated reforming reheat process steps. The finished molded components have largely homogeneous mechanical properties at low residual stresses in the finished molded component, which can lead to problems in subsequent process sections, such as a trimming. After the forming process, the mold component can be trimmed to remove excess material. It is advantageous to cool the mold component of the Endbeschnitt.

To support the isothermal deformation of the moldings are arranged incorporating insulation in the upper tool part and / or lower tool part. As a result of the insulation, the shaping tool components or the shaped bodies are also thermally decoupled from other system components and assemblies of the forming tool. In this way, an impairment of the system components and aggregates is avoided by an inadmissible temperature effect and ensures the reliability for the operating personnel.

The insulation can be supported by cooling. The cooling is arranged in particular on the side of the insulation facing away from the tool between the base body of the upper or lower part of the tool.

Conveniently, the active surfaces of the moldings are provided with a coating. In particular, the coating is carried out by nitriding or a chemical or physical vapor deposition from the gas phase (CVD or PVD). A coating in the form of a DLC (diamond like carbon) layer has at least as good wear, friction and corrosion-reducing properties.

Conveniently, the moldings consist of a tool steel, in particular of a chromium-containing special steel with additions of molybdenum and vanadium. Preferably, a tool steel for the moldings is used, which, based on a warm forging, in the working temperature range of 150 ° C to 400 ° C shows the lowest possible starting effect.

The inventive method for producing a molded component from a metal plate provides that a metal plate is heated to a forming temperature and formed in a forming tool between a heated mold body of a tool shell and a heated moldings of a tool lower part to the mold component. During the forming process thermal expansion of the moldings are compensated.

Dimensional changes as a result of thermal expansion of the shaped bodies with a simultaneously defined position of the shaped bodies in the upper part of the tool or lower part of the tool are made particularly effective.

The storage gives the moldings degrees of freedom in the two-dimensional plane of the moldings. In addition, the moldings are secured by the bearing against rotation. The storage thus captivates the molding (s) while providing thermal expansion. In this case, the storage maintains a fictitious fixed point of the molding or bodies, without hindering the thermal expansion. The fictitious fixed point of storage is ideally close to the mass center of gravity of the moldings.

In an advantageous aspect, the invention relates to a mold component, in particular an automobile component, which is shaped by the method according to this invention. In particular, it is a molded component selected from the group consisting of: bumpers, door impact beams, roof rails, side rails, instrument panel beams, A, B, C or D pillars, pillar reinforcement, transmission tunnels and sills or sill reinforcements.

The invention is explained in more detail with reference to exemplary embodiments illustrated in the drawings. Show it:

1 in a technically simplified representation of an inventive forming tool in a vertical sectional view;

2 the diagram of a storage according to the invention in a plan view;

3 schematically a second embodiment of a forming tool according to the invention and

4 schematically a third embodiment of a forming tool according to the invention.

In the 1 to 4 are mutually corresponding components or component components provided with the same reference numerals.

In the 1 . 3 and 4 is each a forming tool 1A . 1B . 1C shown. Every forming tool 1A . 1B . 1C has a tool lower part 2 and a tool shell 3 on. The lower part of the tool 2 and the tool shell 3 are relocatable relative to each other. In the tool lower part 2 is a heated lower molding 4 and in the tool shell 3 is a heated upper moldings 5 integrated. Between the lower molding 4 and the upper molding 5 is a form space 6 educated.

The lower part of the tool 2 and the tool shell 3 each have a basic body 7 respectively. 8th on, in which the lower moldings 4 or the upper molding 5 is included. The heating of the moldings 4 . 5 via a heating device 9 , In the forming tool 1C according to the 4 is the heater 9 into the moldings 4 respectively. 5 integrated. The to the main body 7 . 8th directed surfaces of the moldings 4 . 5 or the heater 9 are from an insulation 10 surround. The insulation 10 contributes to the support of an isothermal transformation. In addition, the insulation protects 10 adjacent system components and aggregates of the forming tools 1A . 1B . 1C against adverse effects of temperature.

Each between the insulation 10 and the body 7 respectively. 8th is a cooling 11 integrated with cooling components that dissipate residual heat from the heated moldings 4 . 5 to ensure.

It can be seen that the shaped bodies 4 . 5 are segmented and made of individual shaped body segments 12 . 13 . 14 . 15 are formed. The active surfaces of the moldings 4 . 5 or the molded body segments 12 . 13 . 14 . 15 are provided with a coating. Such a coating may, for example, be nitrided or be designed as a DLC layer. The coating is advantageous due to the high tendency to react between the moldings 4 . 5 , which are made of steel, and also ensures a high surface quality of the molded components in the series.

In the tool lower part 2 is also a hold-down 16 integrated, the lower moldings 4 is assigned and encloses this. The hold down 16 is separate to the lower tool part 2 or to the lower moldings 4 vertically displaceable. For the linear displacement is a piston-cylinder system 17 intended.

The 1 . 3 and 4 each show the forming tool 1A . 1B . 1C in open position. During the forming process, the upper part of the tool becomes 3 and the lower tool part 2 moved relative to each other and closed. At the tool base 2 and on the tool top 3 are guide elements 18 . 19 provided that a linear movement of tool upper part 3 and lower tool part 2 ensure each other. In the embodiments shown here are the guide elements 18 . 19 through a rod body on the base body 7 of the lower tool part 2 and a corresponding inclusion in the body 8th of the tool shell 3 educated.

Furthermore, one recognizes in the 3 and 4 in the forming tools 1B respectively. 1C that on the upper molding 5 and at the lower molding 4 or the hold-down 16 , the lower molding 4 is assigned, guide elements 20 . 21 are provided, over which the upper moldings 5 and the lower molded body 4 or the hold-down 16 during the forming process relative to each other are positionally oriented.

The guide elements 20 at the upper molding 5 are formed by slightly conical pins that during the closing process of the forming tool 1B . 1C in the guide elements formed by recordings 21 at the lower molding 4 intervention. The pictures 21 are in the outer molded body segment 15 provided, which part of the hold-down 16 forms.

For forming a metal plate, it is heated to a forming temperature and into the mold space 6 between lower moldings 4 and upper moldings 5 inserted. The forming tool 1A . 1B . 1C is located in the in the 1 . 3 and 4 shown open position. The hold down 16 is in the illustrated ready position, the opposite to the lower moldings 4 shifted upwards in the image plane.

The upper part of the tool is used for forming 3 shifted down. Here come the guide elements 18 . 19 between the tool top 3 and the lower tool part 2 to the intervention. Furthermore, the guide elements move 20 in the form of the pin on the upper molding 5 in the guide elements 21 in the form of recordings on the hold-down 16 , This will be the hold-down 16 fixed. During the downward movement of the upper part of the tool 3 The inserted metal plate first comes with the upper moldings 5 in contact and is between the upper molding 5 and the hold-down 16 clamped. In the further downward movement is from the metal plate in the mold space 6 between the lower mold body 4 and the upper molding 5 molded a molded component.

By heating the moldings 4 . 5 At forming temperature, there is a thermal expansion of the moldings 4 . 5 , Also, the metal plate is heated to forming temperature and thereby expands. At least one molding 4 . 5 in the tool shell 3 and / or in the lower tool part 2 is in a storage 22 arranged. Warehousing 22 is formed such that thermal expansions of the shaped body 4 respectively. 5 be compensated during the forming process. In the embodiments illustrated here according to the 1 . 3 and 4 is the storage 22 the lower moldings 4 assigned.

Warehousing 22 includes, as in the 2 to recognize four camps 23 - 26 in a cross arrangement, which are arranged offset on a pitch circle of 90 ° to each other. Every camp 23 - 26 has an expansion groove 27 and a sliding block 28 on. The nutstone 28 is in the expansion groove 27 guided. The expansion groove allows the unimpeded expansion of the molding during the heating or cooling phase of the tool.

For the forming tools 1A and 1B is the nutstone 28 at the lower heat plate 29 the heater 9 determined, whereas the expansion groove 27 Part of a groove body 30 which is on the lower cooling plate 31 the cooling 11 is attached.

In the forming tool 1C , like in the 4 shown is the sliding block 28 directly on the lower molding 4 established. The groove body 30 is on the cooling plate 31 the cooling 11 arranged and joined.

Basically, the Nutkörper also directly on the body 7 . 8th be set. In this case, then the cooling 11 in the main body 7 . 8th integrated.

By storage 22 become thermal expansions of the moldings 4 . 5 defined compensated. The movements resulting from a force introduction as a consequence of a thermal expansion of the metal plate to be formed are also caused by the bearing 22 balanced. Warehousing 22 ties the molding 4 in the plane (xy). In addition, a rotation of the moldings 4 . 5 prevented. Warehousing 22 ensures that a fictitious fixed point FP of the or the moldings 4 . 5 is maintained without the thermal expansion of the moldings 4 . 5 is hampered. Ideally, the fixed point FP is close to the center of mass of the molded body 4 . 5 ,

LIST OF REFERENCE NUMBERS

1A

forming tool

1B

forming tool

1C

forming tool

2

Tool part

3

Upper die

4

moldings

5

moldings

6

cavity

7

body

8th

body

9

heater

10

insulation

11

cooling

12

Moldings segment

13

Moldings segment

14

Moldings segment

15

Moldings segment

16

Stripper plate

17

Piston-cylinder system

18

guide element

19

Guide element / recording

20

guide element

21

Guide element / Recordings

22

storage

23

camp

24

camp

25

camp

26

camp

27

expansion groove

28

sliding block

29

hotplate

30

groove body

31

cooling plate

FP

fictitious fixed point

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1601478 B1 [0003]
• DE 102006046305 A1 [0004]
• DE 10162437 A1 [0005]
• CH 657548 A5 [0006]

Cited non-patent literature

• EN-AW 5754 [0027]
• EN-AW 5083 [0027]

Claims (12)

Forming tool for the production of molded components made of metal plates, preferably of light metal, which is a tool upper part ( 3 ) and a tool lower part ( 2 ), wherein the upper tool part ( 3 ) and the tool lower part ( 2 ) heated moldings ( 4 . 5 ), characterized in that at least one shaped body ( 4 . 5 ) in the tool upper part ( 3 ) and / or in the tool lower part ( 2 ) in a storage ( 22 ), the storage ( 22 ) is formed such that thermal expansions of the shaped body ( 4 . 5 ) are made possible during the heating process. Forming tool according to claim 1, characterized in that the bearing ( 24 ) at least three, preferably at least four mutually offset bearings ( 23 - 26 ). Forming tool according to claim 1 or 2, characterized in that the storage ( 22 ) one in an expansion groove ( 27 ) guided sliding block ( 28 ) having. Forming tool according to at least one of claims 1 to 3, characterized in that on the upper molding ( 4 . 5 ) and on the lower molding ( 4 . 5 ) and / or on a hold-down ( 16 ) Guide elements ( 18 . 19 . 20 . 21 ) are provided, via which the upper molded body ( 4 . 5 ) and the lower molded body ( 4 . 5 ) and / or the hold-down ( 16 ) are positionally oriented relative to each other during the forming process. Forming tool according to at least one of claims 1 to 4, characterized in that the molding or the ( 4 . 5 ) is / are segmented. Forming tool according to at least one of claims 1 to 5, characterized in that a heating device ( 9 ) is provided for the temperature control of the moldings ( 4 . 5 ) to a temperature of 150 ° C to 350 ° C, preferably to a temperature of 200 ° C to 300 ° C. Forming tool according to at least one of claims 1 to 6, characterized in that the shaped bodies ( 4 . 5 ) incorporating insulation ( 10 ) in the tool upper part ( 3 ) and / or in the tool lower part ( 2 ) are arranged. Forming tool according to at least one of claims 1 to 7, characterized in that the active surfaces of the molded body ( 4 . 5 ) have a coating (12). Forming tool according to at least one of claims 1 to 8, characterized in that a cooling ( 11 ) is provided. Forming tool according to at least one of claims 1 to 9, characterized in that the shaped bodies ( 4 . 5 . 6 ) consist of a tool steel, in particular of a chromium-containing special steel with additions of molybdenum and vanadium. Method for producing shaped components from a metal plate, preferably from a light metal plate, in which the metal plate is heated to a forming temperature and in a forming tool between a heated molded body ( 4 . 5 ) of a tool shell ( 3 ) and a heated molding ( 4 . 5 ) of a tool lower part ( 2 ) is formed into a molded component, characterized in that during the heating process, a thermal expansion of the moldings ( 4 . 5 . 6 ). Method according to claim 11, characterized in that dimensional changes of the shaped bodies ( 4 . 5 ) as a result of thermal expansion at a defined position of the moldings ( 4 . 5 ) in the tool upper part ( 3 ) and / or tool base ( 2 ).

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