DE102017207525A1 - A method of making a coolable mold and method of making a molded part - Google Patents

Abstract

The invention relates to a method for producing a coolable mold and a method for producing a molded component, in particular a hot-formed metal component.
A method for producing a coolable molding tool (10) is provided, wherein a metallic base body (12) having a first surface (21) is provided, which has at least one concave depression (14) opened to the first surface (21). having. The recess (14) is at least partially covered with a metal part (16) for the purpose of producing at least one section of a fluid channel (15). The metal part (16) is produced by means of a generative manufacturing process, in particular by means of a 3D printing process.

Description

The invention relates to a method for producing a coolable mold and a method for producing a molded component, in particular a hot-formed metal component.

In the hot forming molds are used for forming metal parts, between which the metal parts are transformed by applying a forming force. The metal parts, such as sheets or molded blanks, are previously heated to a forming temperature, which may be more than 800-900 ° C depending on the method. This is used for example for the production of body parts for motor vehicles.

For an efficient and robust process, it is desirable and well-known that the said molds are cooled. In this way, overheating of the molds can be avoided, which prevents a heat-related reduction in strength. Thus, the mechanical stability of the mold can be guaranteed throughout the process and thus a long life or a high number of use cycles is possible. Furthermore, a high throughput can be achieved, since due to the cooling between the individual forming processes no operational interruptions are necessary.

To realize such a cooling fluid channels are arranged during the manufacture of the mold, through which a cooling medium for the purpose of absorbing heat energy from the mold can circulate. In this case, the necessary mechanical stability of the mold is to be considered, which requires a sufficient cover layer over the fluid channels. The often irregular shapes of the cooling tools represent a manufacturing challenge.

Different cooling tools and methods for the production of cooling tools are known from the prior art. The DE 10 2014 221 423 A1 discloses a method of manufacturing a hot forming tool having a shell member and a base body, wherein the shell member providing an effective surface of the hot forming tool is manufactured by a generative manufacturing method. In this case, a channel-shaped cavity is arranged by releasing areas in the generative manufacturing process in the shell element, which forms a fluid channel or a part of a fluid channel. The fluid channel can follow a contour of the effective surface. The base body is produced by casting the shell element behind with a cast material. There may be a post-processing of the contour of the shell element by means of milling or lasers.

The DE 10 2014 112 526 A1 describes a mold with a shaping surface for a workpiece to be produced. This comprises at least one integrated tempering channel, which is limited by two sub-tools together. In particular, the temperature-controlled grooves are arranged only in one of the two sub-tools, while they are covered by the other part tool. The latter can have a completely flat surface and cover with it several or all channels. A forming surface for a workpiece to be produced is provided by one of the sub-tools.

The WO 2011 110 346 A2 discloses a method of making a coolable mold. A metallic partial body of a molding tool is produced, which has fluid paths on a surface. These are protected against penetration by particles and a cover layer is applied over the protected fluid paths. For protection against particles, a filling medium can be introduced. The cover layer can be applied by means of a thermal coating method, for example by means of arc spraying.

Individual aspects of conventional methods for the production of molds are in the 1 to 3 shown.

1 shows a part of a mold during manufacture. This comprises a base body 12 with elongated recesses 14 with a respective semicircular profile for receiving tubes with a circular cross-section. In the recesses 14 15 copper tubes 40 are arranged for the purpose of formation of fluid channels. These run in a common plane on the first surface 21 of the base body 12.

The connection of the copper tubes 40 to the base body 12 is welded by means of welds, z. B, welds, realized. Due to the different materials, this is expensive. Furthermore, due to the risk of buckling in the production of copper tubes 40, the curve is limited to large radii. In addition, the connection of the intermediate step shown here with a covering layer, which is necessary for the subsequent production of the shaping surface, for example using an overlay welding method, is also difficult due to the different materials.

2 shows an alternative known variant for the production of a mold 10. Here, for the preparation of the fluid channels 15 in the base body 12 arranged recesses 14 are covered with metal parts 16, namely with laser-cut, bent steel sheets. These close flush with the first surface 21 of the body. In the right area of the illustration, the recesses 14 are opened and shown covered in the left area.

Due to the manufacturing process, the possibilities of shaping the metal parts 16 are limited. For this reason, geometrically simple steel sheets are arranged here and the fluid channels 15 are straight in the regions of the recesses 14 covered with the metal parts 16. For the purpose of closing the fluid channels in the edge regions of the molding tool 10 shown, therefore, lateral deflection plates 42 with deflection bores are arranged, which are expensive and expensive to manufacture. In addition to the limited shape and the production of the metal parts 16 by individual laser and bending is complex and expensive.

3 shows a further embodiment in which a three-dimensionally bent metal part 16 is placed over corresponding recesses 14. The recess 14 facing side of the metal part 16 covers the recess 14 from. Here, the base body 12 is shown only on the basis of its outer surfaces. Thus, the viewing direction follows into the interior of the base body 12 and the fluid channels 15 are shown from below by means of the walls of the recesses 14.

This embodiment is very expensive and expensive, since the metal part 16 must be bent into a complex, meandering, three-dimensional shape.

It is the object of the invention to provide a method for producing a coolable molding tool with which a coolable by means of a cooling medium mold can be produced in a simple and cost-effective manner, with which in turn efficiently a molded component can be provided.

The object is achieved by the method for producing a coolable mold according to claim 1. Another aspect of the invention is a method for producing a molded component, in particular a hot-formed metal component, according to claim 10. Embodiments of the method for producing a coolable mold are in the Subclaims 2-9 specified.

A first aspect of the invention is a method for producing a coolable mold, wherein a metallic base body having a first surface is provided which has at least one concave depression opened to the first surface. The recess is at least partially covered with a metal part for the purpose of producing at least a portion of a fluid channel. The metal part is produced by means of a generative manufacturing process, in particular by means of a 3D printing process.

The body is typically a solid metal body, such as cold drawn steel. At its first surface at least one and in particular a plurality of concave depressions is arranged.

The concave recess is a recess or an open cavity and provides a part of a fluid channel to be produced. It can be of any shape and, for example, have a rectangular, circular, U-shaped or irregular cross-section. The depression has a wall which delimits it from the material of the base body. In this case, the depression forms an edge with the base body at the transition region between the wall and the first surface. In a simple embodiment, this can be designed, for example, as an edge, possibly as a rectangular edge. The edge can be rounded. In particular, the base body on both sides of the recess has the same height, so that the edges are arranged in a common plane with at least the adjacent areas of the first surface.

The recess may be elongated and is typically open at its end faces to have, after closing the recess to the first surface by means of the metal part inflows and outflows for a cooling medium. By way of example, a meander-shaped fluid channel can extend over wide regions of the molding tool and have parallel sections which can run, for example, parallel to the first surface. The metal part is typically a flat or plate-shaped part, in particular a sheet metal part. It has a thickness between 0.4 mm and 3 mm, in particular between 0.7 mm and 2 mm and for example between 1 mm and 1.5 mm. Its length and width are typically many times greater than its thickness.

Since the forming surface of a mold and thus also the first surface typically have a curved contour, the metal part may have a spatially curved shape. In particular, a plurality of metal parts is used for a plurality of fluid channel sections, which have different shapes due to their different positions on the spatially curved first surface. By means of the generative manufacturing process, for example the 3D printing process, it is thus possible to produce an exactly fitting metal part for every position with little effort. In this way, a simple and inexpensive production of the mold is possible.

When the recess is covered, the metal part is typically placed over the depression in such a way that it rests on both sides of the recess at least partially and in particular substantially continuously against the first surface. In this case, overlapping areas form between the metal part and the base body, which possibly cover the edges of the depression. The metal part can be fixed to the base body after arranging on the base body or placing it on the base body for the purpose of covering the recess or sealing the overlapping areas.

In particular, the mold to be produced is a tool for the hot forming of metal parts. However, it is also not excluded that by means of the method according to the invention molds or parts thereof for a primary molding process, for example for the injection molding of plastic parts, can be produced. Cooling is also desirable in such tools. In general, any molding tools for molding articles or shapeless fabrics can be made by the method of the invention.

Typically, generative laser deposition welding is used to close the fluid channel. In this case, however, creates a porous structure, which makes the cooling medium over a dense configuration of the fluid channel consuming. By means of the metal part used for covering, in particular in conjunction with a tight fixation at the edge regions of the depression, a dense configuration of the fluid channel can be easily achieved.

In one embodiment of the method, a recess is arranged at least in sections, in particular substantially continuously, in the transition region between the depression and the first surface. The metal part is arranged with at least one edge region in the recess such that a side of the metal part facing the depression is closer to the depression than the plane in which the first surface extends.

In the transition region between the depression and the first surface, in particular, as described, a wall of the depression adjoins the first surface. In this area, instead of the simple edge, the recess is now arranged, which is typically shaped in the manner of a Einlegeut. Thus, the metal part can be arranged with its edge regions in such a way that a positive connection with the edges of the recess is made, as a result, the metal part is fixed against displacement in the plane defined by the first surface.

In particular, the recess extends substantially continuously or substantially circumferentially about the recess. Thus, the recess of the facing side of the metal part, ie its bottom, are completely submerged. It is not excluded that in some areas of the edges no recess is arranged or the recess is interrupted. Such a recess can be made for example by milling.

The plane in which the first surface extends is defined in particular by the regions of the first surface which adjoin the depression or the recess. In other words, the metal part is sunk in covering the recess in the recess such that its underside is lower than the adjacent areas of the first surface.

This results in the advantage that the metal part is secured against slippage or displacement.

In a further embodiment, the metal part and the recess are configured such that the metal part terminates substantially flush with the first surface.

In particular, the thickness of the metal part, which may be approximately the same in all areas of the metal part, substantially corresponds to the height of the recess. Thus, the metal part can be completely sunk in the recess to form a flat surface.

The side of the metal part facing away from the recess thus lies substantially in the plane defined by the first surface.

In particular, it is meant that the metal part to the first surface has a height difference of less than 2 mm, in particular less than 1 mm and for example less than 0.5 mm. It thus does not protrude substantially beyond the main body nor does it form a substantial depression of the first surface.

This has the advantage that a flat, uninterrupted surface is produced, which brings advantages in the further processing of the molding tool or is suitable as such for the forming of components.

In one embodiment, the metal part is fixed by welding on the base body.

In particular, it is meant that for fixing the metal part to this by means of welding at least partially and in particular completely a welded cover layer is applied, as described below. With this it is fixed in the border areas. Alternatively, the metal part, which is designed for this purpose in particular significantly thicker than described above, be fixed by means of producing a circumferential weld tightly against the body. This can be done in all embodiments with or without recess and it is generated in this way a shaping surface of the mold.

This embodiment has the advantage that a firm and mechanically stable connection between the metal part and the base body can be produced.

In a further embodiment, a cover layer is applied to at least one region of the metal part and in particular to the entire metal part.

In particular, a metallic cover layer is meant. This provides a surface of the mold called the second surface. This is set up in particular for contacting with components to be formed for the purpose of realizing the deformation, ie it is a shaping surface.

In one embodiment, such a cover layer can be placed as a solid body on at least one metal part or on the base body provided with at least one metal part and in particular fixed. For example, the shaping surface can be realized by means of at least one solid surface element, which covers one or more parts of the entire base body including the metal parts and thus forms the entire second surface. The cover layer can be arranged independently of the presence of the recess.

In one embodiment, the application of the cover layer by means of build-up welding, in particular by laser deposition welding. The cover layer can fix the metal part on the base body.

In laser deposition welding, also called generative laser cladding, a shapeless metallic material, for example a powder or a wire or strip, is liquefied by means of laser radiation and applied to the likewise partially heated and melted in the surface area workpiece. This creates a metallurgical bond that contributes to a layered application of material.

The layer applied in this way can have a thickness between 3 mm and 30 mm, in particular between 5 mm and 20 mm, and for example between 8 mm and 13 mm. It can therefore be many times thicker than the metal part. Thus, large strengths can be achieved, so that the molds thus produced reach long service life.

In particular, the second surface, that is to say the shaping surface, is produced completely, at least in the region of the metal part, by applying welding material, in particular by means of laser deposition welding.

Typically, the entire second surface is made by applying welding material. In other words, the entire first surface is welded together with the metal parts. The metal part protects the recess or the subsequent fluid channel against the penetration of weld metal.

The laser cladding has the advantage that the temperature input to the surface of the metal part is well metered. Thus, thin metal parts can be used to cover the depression, without that they melt during application of the cover layer. Alternatively, the cover layer can be applied by any generative method.

In one embodiment, a defined by the cover layer second surface of the mold is treated for the purpose of smoothing with a separating manufacturing process, in particular with a mechanical method, such. B. milling.

The second surface is the side of the cover layer facing away from the metal part, that is to say an outer surface of the molding tool or a shaping surface. In particular, it is mechanically treated to provide a smooth forming surface. Alternatively, it may be treated by ablation, such as thermal or chemical.

The second surface is set up in this way for contacting with a component to be formed. In other words, the shaping surface of the molding tool by means of Post-processing made. In particular, cutting-edge production methods are used for this, such as, for example, milling. For this purpose, a defined allowance is typically taken into account during the previous application of the cover layer and, for example, material with a thickness of between 1 mm and 4 mm is additionally applied so that the desired layer thickness is achieved by the separating treatment.

The resulting advantage is that the desired forming surface can be made in a simple and accurate manner.

In a further embodiment, a plurality of depressions are covered with metal parts, in particular with one metal part each.

As described, for example, several sections of a meandering channel can be covered. These can be shaped differently in particular. Several metal parts may be arranged to cover one or more recesses. In this case, each metal part may extend over at least portions of one or more recesses.

In particular, a cover layer is subsequently applied to all metal parts and to the intermediate areas of the surface of the molding tool. In this case, the entire surface of the molding tool can be provided with a cover layer, so that all areas provided for contacting with components to be formed have the cover layer. The resulting surface is in particular completely finished by milling or smoothed.

In this way, the advantage is achieved that the entire shaping surface is coolable, since it is completely traversed by fluid channels.

In a further embodiment, the metal part and the base body are made of the same material, in particular of steel.

This results in the advantage of good weldability, so that the connection of the two parts can be easily made.

A second aspect of the invention is a method for producing a molded component, in particular a hot-formed metal component. A coolable molding tool produced by the method according to the invention and a component to be molded, in particular a metal component, or a shapeless material are provided. The component is at least partially reshaped by means of the molding tool or the fabric is shaped by means of the molding tool.

During molding of the component, in particular during forming, a force is exerted on at least one region of the component which at least partially reshapes the component. This results in a contact of the component with the mold. It comes to a concern of the component to the mold, wherein a corresponding second mold can rest on the opposite side of the component, and the component is thus formed between the molds.

In particular, before, during and / or after the forming of the component cooling of the mold takes place. For this purpose, a cooling medium for the purpose of absorbing thermal energy from the mold is passed through at least part of a fluid channel of the mold and subsequently cooled down again if necessary. In this way, overheating of the tool can be effectively prevented or a desired temperature range can be set.

When hardening the metal part is quenched to obtain a martensitic structure. A large part of the heat of the heated metal component must be dissipated for this purpose during the forming or in direct connection to the outside. For this purpose, cooling of the molding tools according to the invention with at least one fluid channel is particularly advantageous.

For carrying out the method, in the case of hot forming, the molding tool, in particular together with a corresponding second molding tool and this opposite, used in a press, so that the tools to be formed can exert the corresponding forming force on the component to be formed.

However, it is also not excluded that the method is an injection molding process, for example for the transformation of plastic.

Another aspect of the invention is a motor vehicle, in particular a passenger car, which has a component produced by the method according to the invention for producing a molded component. This may be, for example, a hot-formed metal component, for example a body component. Alternatively, it may be an injection molded part, for example, a trim part made of plastic.

The invention will be explained below with reference to the embodiments illustrated in the accompanying drawings.

• 1: eine perspektivische Darstellung eines Zwischenschrittes der Herstellung eines aus dem Stand der Technik bekannten Formwerkzeugs,
• 2: eine perspektivische Darstellung eines Zwischenschrittes der Herstellung eines weiteren aus dem Stand der Technik bekannten Formwerkzeugs,
• 3: eine perspektivische Darstellung eines Zwischenschrittes der Herstellung eines dritten aus dem Stand der Technik bekannten Formwerkzeugs,
• 4: eine schematische perspektivische Darstellung mehrerer Schritte des erfindungsgemäßen Verfahrens zur Herstellung eines Formwerkzeugs, sowie
• 5: eine Schnittzeichnung einer Ausführungsform eines mit dem erfindungsgemäßen Verfahren hergestellten Formwerkzeugs,

Show it

• 1 FIG. 2 is a perspective view of an intermediate step of manufacturing a mold known in the prior art. FIG.
• 2 FIG. 2: a perspective view of an intermediate step of the production of another molding tool known from the prior art, FIG.
• 3 FIG. 2: a perspective view of an intermediate step of the production of a third mold known from the prior art, FIG.
• 4 a schematic perspective view of several steps of the inventive method for producing a mold, and
• 5 FIG. 3 is a sectional view of an embodiment of a molding tool produced by the method according to the invention, FIG.

On the 1 to 3 has already been discussed to explain the state of the art.

4 shows schematically several steps of the production of a mold 10 with the method according to the invention. The main body 12 points to its first surface 21 concave depressions 14 on, the sections of a meandering fluid channel 15 are. These sections are at the edges of the mold 10 connected by means of curve sections, so that a continuous fluid channel 15 is formed. The curve sections have a larger distance to the first surface 21 on or are located lower lying in the body than the parallel sections.

The depression located on the left side 14 is shown in the open state. The next recess 14 is shown in the partially closed state: a metal part 16 That is, a metal sheet having a thickness of about 1 mm, which is produced here by a 3D printing method, which is shown here schematically in half, covers the recess 14 from.

It is at the edge of the wells 14 to the first surface 21 a circumferential, continuous recess 18 arranged in the form of an insertion groove. Therein is the metal part 16 arranged so that its bottom is lower than the plane in which the first surface 21 runs, and the metal part 16 Accordingly protected against lateral slippage.

The fourth depression seen from the left 14 is partially with a cover layer shown separately for visibility reasons 19 covered, which consists of the same material as the metal parts 16 , The other wells 14 are also covered, with the topcoat 19 altogether a closed ceiling, namely the second surface 22 forms as shown in the right image area. The second surface 22 is intended for contacting with reshaped components, the entire body 12 as well as all metal parts 16 covering molding surface of the mold 10 , It can be seen that all metal parts 16 have different sizes and shapes, which is easy and inexpensive to implement by means of the 3D printing process.

The cover layer 19 This is a 10 mm thick metal layer applied by generative laser deposition welding, which also fixes the metal parts 16 at the base body 12 realized. During welding, the metal parts prevent 16 , which are protected against slipping as described to facilitate welding, penetration of weld metal into the recess 14 or in the fluid channel to be produced 15 ,

5 shows a section produced by a method according to the invention mold 10 , Below is the main body 21 pictured at his first surface 21 a concave depression 14 for forming a fluid channel 15 having. The first surface 21 is by means of its wall 32 from the main body 12 demarcated.

In the transition area 30 between the depression 14 and the first surface 21 is a recess 18 in the form of a stepped shape of the wall 23 arranged. Both edge regions of the metal part 16 are arranged in this. The deepening 14 facing side 17 of the metal part 16 is closer to the well 14 is located as the plane in which the first surface 21 runs. The metal part closes 16 flush with the first surface 21 from.

Above the metal part 16 and the first surface 21 of the basic body 12 is the topcoat 19 arranged the second surface 22 , So the molding surface of the mold 10 , trains.

LIST OF REFERENCE NUMBERS

mold 10 body 12 deepening 14 fluid channel 15 metal part 16 page 17 recess 18 topcoat 19 First surface 21 Second surface 22 Transition area 30 wall 32 copper pipe 40 baffle 42

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

• DE 102014221423 A1 [0005]
• DE 102014112526 A1 [0006]
• WO 2011110346 A2 [0007]

Claims (10)

A method of making a coolable mold (10), comprising: - providing a metallic base (12) having a first surface (21) having at least one concave depression (14) open to the first surface (21); Recess (14) for the purpose of producing at least a portion of a fluid channel (15) at least partially covered with a metal part (16), characterized in that the metal part (16) by means of a generative manufacturing process, in particular by means of a 3D printing process is prepared. Method for producing a coolable mold (10) according to Claim 1 , characterized in that in the transition region (30) between the recess (14) and the first surface (21) at least in sections, in particular substantially continuously, a recess (18) is arranged and the metal part (16) with at least one edge region in such the recess (18) is arranged so that one of the recess (14) facing side (17) of the metal part (16) closer to the recess (14) is located as the plane in which the first surface (21) extends. Method for producing a coolable mold (10) according to Claim 2 , characterized in that the metal part (16) and the recess (18) are configured such that the metal part (16) with the first surface (21) is substantially flush. Method for producing a coolable molding tool (10) according to one of the preceding claims, characterized in that the metal part (16) is fixed to the base body (12) by means of welding. Method for producing a coolable molding tool (10) according to one of the preceding claims, characterized in that a cover layer (19) is applied to at least one region of the metal part (16) and in particular to the entire metal part (16). Method for producing a coolable mold (10) according to Claim 5 , characterized in that the application of the cover layer (19) by means of build-up welding, in particular by laser deposition welding, takes place. Method for producing a coolable molding tool (10) according to one of Claims 5 and 6 , characterized in that by the cover layer (19) defined second surface (22) of the mold (10) is treated for the purpose of smoothing with a separating manufacturing process, in particular with a mechanical method, such. B. milling. Method for producing a coolable molding tool (10) according to one of the preceding claims, characterized in that a plurality of concave depressions (14) are covered with metal parts (16), in particular with one metal part (16) each. A method for producing a coolable mold (10) according to any one of the preceding claims, characterized in that the metal part (16) and the base body (12) are made of the same material. A method for producing a molded component, in particular a hot-formed metal component, in which a with the method according to one of Claims 1 - 9 manufactured coolable mold (10) and a component to be molded, in particular a metal component, or a shapeless material are provided, and the component by means of the molding tool (10) is at least partially reshaped or the fabric by means of the molding tool (10) is formed.

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