EP0953392A1 - Process for making permanent moulds - Google Patents

Abstract

The die blank is divided into parallel layers which are then provided with grooves for accommodation of cooling pipes. The die blank is divided into parallel layers (1) in such a way that contours (3) of the subsequent forming surface are repeatedly intersected by these layers. Each layer is provided with at least with one groove running close to the forming surface contours. Coolant pipes (2) are inserted into these grooves and fixed in position. The assembled layers with pipes are placed into a sheet metal container (5) which is then put under vacuum and sealed. The container is subjected to hot isostatic compression so that the layers (1) are diffusion welded to one another and to the pipes (2). The resultant die is characterized in that it consists of known die steels.

Description

The invention relates to a method for introducing spatially designed, tempering metal Pipelines in a permanent metal form for primary shaping of metals or plastics under pressure, whereby the pipes the spatial course of the engraving areas of the cavity (mold cavity) at least largely be adjusted.

Permanent forms for the primary shaping of metals under pressure, for example of die-cast aluminum or zinc or of plastics, by pressure or injection molding, as well as mold inserts or cores in the area of the cavity Permanent forms are often used with tempering Channels. These channels are used during the Original molding with a coolant that the Control of heat dissipation during solidification and cooling of the molded part.

The channels are mainly produced by drilling and therefore run straight. Adjusting the channels to a spatial course of the engraving areas of the Cavity is therefore very difficult. For this purpose, in generally many holes from appropriate directions introduced and connected together in the form. There a large part of the holes from auxiliary holes exists, they have to be closed again later. Despite the high manufacturing costs, the can The above-mentioned channels are only produced in sections follow the engraving. Therefore, the so produced are sufficient Permanent forms under heat transfer aspects the requirements are often very inadequate. About that the necessary auxiliary holes also form static ones Weaknesses of the highly stressed permanent forms that lead to Starting point of signs of fatigue and can lead to failure of the permanent form.

In another known method, the Tempering channels formed in such a way that the permanent form first in simple space-filling geometrical Bodies, such as plates, cylinders, cones or the like, be disassembled. The channels then become into these bodies milled in. After that, the individual bodies are under Insertion of seals reassembled. This The procedure can only be used if the decomposition the permanent form can be made so that the individual body at least partially contain. A permanent form with this procedure channels formed compared to a permanent form drilled channels have less rigidity. Furthermore sealing problems can occur.

A powder metallurgical process is also known, that allows any temperature control system to be designed in Introduce die casting molds (DE 44 26 544 A1). At This process uses a metal channel Modeled material, especially copper. The spatially shaped metal rods are initially in one Tin containers that contain or represent the later form should be laid in terms of construction. Then the Container filled up with a metal powder and gas-tight locked. After that, the metal powder becomes hot isostatic compacted. Following this, the Metal rods melted out of the molded body and thus the cooling channels exposed.

From the literature (Powder Matallurgy 1996, Vol. 39, No. 4) is another powder metallurgy process known, spatially in the steel piping laid anywhere in a container and at the ends with can be welded gas-tight. Analogous to the above described method is the container with Filled in metal powder, sealed gastight and hot isostatic pressed. Because the steel pipes in this known methods from the inside with the pressure medium When the hot isostatic press is applied, its opening cross-section remains during the compacting process until largely unaffected by isotropic shrinkage.

Draw the latter two known methods through their almost unlimited spatial design freedom out. However, these methods have so far only been found little spread. This is due to the fact that the accuracy of the cable routing in the finished form is significantly restricted and therefore in stark contrast to the otherwise usual high precision of mold making stands. This lack is the result of not very precisely predictable shrinkage of the molded body during Compacting process. In mold making, the powder metallurgy Process not known.

The invention has for its object a method for installing spatially designed pipelines in to create a metal permanent shape that enables the pipes are largely free in space, but with high positional accuracy and inside one metal permanent form to connect materially and positively.

• daß die Dauerform bzw. der zu kühlende Formkörper oder Formeinsatz in eine Vielzahl planparalleler Schichten, wie Rechteck-, Vieleck-, Zylinderplatten u. dgl., zerlegt wird, die so bemessen sind, daß die spätere Gravur von den Schichten vielfach geschnitten wird,
• daß jede Schicht mit mindestens einer Nut versehen wird, wobei die Nuten derart angeordnet werden, daß sie mit dem gewünschten Verlauf der Kühlrohre entlang der Kontur der später einzuarbeitenden Gravur übereinstimmen,
• daß in die Nuten die Kühlrohre eingefügt und befestigt werden,
• daß die Schichten in der richtigen Reihenfolge lagengenau zu der Gesamtform zusammengelegt und fixiert werden,
• daß die zusammengelegten und fixierten Schichten in einen die Gesamtform allseitig engumschließenden Blechcontainer eingekapselt werden, wobei der Blechcontainer im Bereich der austretenden Kühlrohre entsprechende Öffnungen aufweist, durch die die Kühlrohre hindurchgeführt sind,
• daß der Blechcontainer gasdicht verschlossen und luftleer gepumpt wird
• und daß der Blechcontainer derart heißisostatisch gepreßt wird, daß die einzelnen Schichten untereinander und mit den Kühlrohren diffusiv verschweißt werden.

The problem is solved in the method of the type described at the outset by

• that the permanent mold or the molded body to be cooled or mold insert in a plurality of plane-parallel layers, such as rectangular, polygonal, cylindrical plates and. Like., is disassembled, which are dimensioned such that the later engraving is often cut by the layers,
• that each layer is provided with at least one groove, the grooves being arranged in such a way that they correspond to the desired course of the cooling tubes along the contour of the engraving to be incorporated later,
• that the cooling tubes are inserted and fastened in the grooves,
• that the layers are put together and fixed in the correct order to form the overall shape,
• that the collapsed and fixed layers are encapsulated in a sheet metal container that closely encloses the overall shape on all sides, the sheet metal container in the area of the emerging cooling tubes having corresponding openings through which the cooling tubes are passed,
• that the metal container is closed gas-tight and pumped air-free
• and that the sheet metal container is so hot isostatically pressed that the individual layers are welded to one another and to the cooling tubes diffusively.

Because every cut surface of the individual layers is intended to accommodate at least one cooling tube the number of layers by the number of required Cooling pipes set.

After completion of the method according to the invention, all are Parts metallurgically connected. The diffusion welded Layers are no longer separable.

The contact areas of the individual layers are so intimate connected that they neither by ultrasonic testing nor can be found metallographically. The firmness the diffusion composite does not differ from that Strength of the base material of the permanent mold.

The manufactured by the inventive method Diffusion-welded permanent shape can be soft annealed and edit in any other way, for example to incorporate the engraving into the permanent shape.

In an embodiment of the invention is between the merged and fixed layers and the tin container a metal or ceramic powder bed brought in.

The powder bed has - depending on the type of chosen Powder beds - different effects. A metal one Powder bed, suitably made of the same type of material steel powder is elected if a firm connection after hot isostatic pressing to be brought about to the layers. Here the powder bed serves to fill gaps, gaps and voids balance. A ceramic, not sintered Powder bed, for example made of aluminum or zirconium oxide, has the opposite effect. In this case hot isostatic pressing does not create a connection between the layers and the powder bed as well as the Tin container formed so that the container to Can be removed with little effort.

The method according to the invention can still do this be improved that the tin container before closing flushed with inert gas, preferably nitrogen and that the closing of the tin container under Inert gas takes place. This is conveniently done Closing the sheet metal container at ambient pressure.

In a further embodiment of the invention Disassembly of the permanent mold or the molded body to be cooled or use of mold in layers both vertically as well as horizontally to the mold parting line. The permanent form thus consists of vertical and / or horizontal and / or mixed stacks of plane-parallel layers.

According to another feature of the invention Disassembly of the permanent mold or the molded body to be cooled or use of mold in layers both vertically as well as horizontally to the closing direction of the mold.

In certain cases it may be advantageous that the Disassembly of the permanent mold or the molded body to be cooled or mold insert in layers in any Space arranged levels takes place.

In a preferred embodiment of the after Processed metal according to the invention Permanent form for archiving metals or plastics under pressure is the permanent mold made of known mold steels, like tool and high speed steels, educated.

In another embodiment of the according to the invention Process manufactured metal permanent mold for archiving metals or plastics under Print is the permanent form from known nickel, copper or Aluminum alloys formed.

The above materials have been in the Mold making well proven.

A particularly useful embodiment of the object the invention is that for Cooling pipe steels, especially stainless steels, or Nickel, copper and aluminum alloys are used become.

The individual layers are expediently the Permanent mold or the molded body or mold insert to be cooled provided with ventilation channels.

The manufactured by the inventive method Permanent form can still be improved in that the individual layers of the permanent form or the one to be cooled Shaped body or insert with a profile are provided. As a result, the contact surfaces of the individual layers interlocked.

This can further improve the permanent form achieved that the individual layers of the Permanent shape or the molded body to be cooled or Mold insert are provided with pins, pins or the like, in the corresponding recesses in the respective adjacent layers are provided to intervene. This is a very precise fixation of the components the permanent form before it is welded diffusively.

It can be useful for certain courses of the cooling pipes be between or next to those with at least at least one additional layer provided with a groove Layer is provided which has no groove.

Fig. 1

eine Draufsicht auf eine Dauerform;

Fig. 2

eine Vorderansicht eines Teils einer Dauerform;

Fig. 3

mehrere Schichten einer Dauerform in der Art einer Explosionszeichnung;

Fig. 4

eine Vorderansicht eines anderen Teils einer Dauerform;

Fig. 5

mehrere Schichten einer anderen Dauerform in der Art einer Explosionszeichnung;

In the drawing, exemplary embodiments of permanent molds produced by the method according to the invention are shown schematically. Show it:

Fig. 1

a plan view of a permanent shape;

Fig. 2

a front view of part of a permanent mold;

Fig. 3

several layers of a permanent form in the manner of an exploded drawing;

Fig. 4

a front view of another part of a permanent shape;

Fig. 5

several layers of another permanent form in the manner of an exploded drawing;

The permanent forms shown in the drawing are in Layers 1 disassembled and point in the area of Cut surfaces of the layers 1 cooling lines 2. The Cooling lines 2 are adapted to the engraving 3 of the cavity. For the sake of a better overview, in FIG. 1 the cooling lines 2 represented by thin solid lines.

The layers 1 forming the permanent shape are provided with grooves 4 provided (Fig. 3) into which the cooling lines 2 are inserted are. However, an additional layer 1 ' be provided that has no groove. Like from the 1 and 2 can be seen, are the merged and fixed layers 1 from a sheet metal container 5 encapsulated from which the cooling lines 2 to the outside stand out.

As can be seen from FIG. 4, the layers 1 the permanent form with a profile 7 and / or with Pin 8 may be provided.

In the embodiment shown in Fig. 5 the layers 1 of the permanent form have ventilation channels 6 on.

Claims (14)

Process for introducing spatially designed, temperature-regulating metal pipelines into a metal permanent mold for the primary shaping of metals or plastics under pressure, the pipelines being at least largely adapted to the spatial course of the engraving surfaces of the cavity (mold cavity),
characterized,

1.1

that the permanent shape or the molded body to be cooled or mold insert in a plurality of plane-parallel layers (1), such as rectangular, polygonal, cylindrical plates and. Like., is disassembled, which are dimensioned so that the later engraving (3) of the layers (1) is cut many times,

1.2

that each layer (1) is provided with at least one groove (4), the grooves (4) being arranged in such a way that they correspond to the desired course of the cooling pipes (2) along the contour of the engraving (3) to be incorporated later,

1.3

that the cooling tubes (2) are inserted and fastened in the grooves (4),

1.4

that the layers (1) are put together and fixed in the correct order to form the overall shape,

1.5

that the collapsed and fixed layers (1) are encapsulated in a gas-tight sheet metal container (5) which encloses the overall shape on all sides, the sheet metal container (5) having corresponding openings in the area of the emerging cooling tubes (2) through which the cooling tubes (2) pass are,

1.6

that the sheet metal container (5) is pumped air-tight and sealed gas-tight

1.7

and that the sheet metal container (5) is pressed so hot isostatically that the individual layers (1) are welded to one another and to the cooling tubes (2) diffusively.

A method according to claim 1, characterized in that between the merged and fixed Layers (1) and the metal container (5) a metal or ceramic powder bed is introduced. A method according to claim 1 or 2, characterized in that that the sheet metal container (5) before Sealing with inert gas, preferably nitrogen, is rinsed and that the closing of the tin container (5) was carried out under inert gas. A method according to claim 3, characterized in that the closing of the sheet metal container (5) Ambient pressure. Method according to one of claims 1 to 4, characterized characterized that the decomposition of the permanent form or of the molded body or insert to be cooled in Layers (1) both vertically and horizontally to the mold parting level. Method according to one of claims 1 to 4, characterized characterized that the decomposition of the permanent form or of the molded body or insert to be cooled in Layers (1) both vertically and horizontally to the closing direction of the mold. Method according to one of claims 1 to 4, characterized characterized that the decomposition of the permanent form or of the molded body or insert to be cooled in Layers (1) in any level arranged in space he follows. According to the method according to one of claims 1 to 7 manufactured permanent metal form for the primary shaping of Metals or plastics under pressure, characterized in that the permanent mold made from known mold steels, like tool and high-speed steels is formed. According to the method according to one of claims 1 to 7 manufactured permanent metal form for the primary shaping of Metals or plastics under pressure, thereby characterized in that the permanent form from known Nickel, copper or aluminum alloys are formed is. Permanent form according to claim 8 or 9, characterized in that for the cooling tubes (2) steels, in particular Stainless steels, or nickel, copper and Aluminum alloys are used. Permanent form according to claim 8, 9 or 10, characterized in that that the individual layers (1) of Permanent shape or the molded body to be cooled or Provide mold insert with ventilation channels (6) are. Permanent form according to one of claims 8 to 11, characterized characterized in that the individual layers (1) of Permanent shape or the molded body to be cooled or Provide the mold insert with a profile (7) are. Permanent form according to one of claims 8 to 11, characterized characterized in that the individual layers (1) of Permanent shape or the molded body to be cooled or Provide mold insert with pins (8), pins or the like are in corresponding recesses, the provided in the respective adjacent layers (1) are to intervene. Permanent form according to one of claims 8 to 13, characterized characterized in that between or next to the with layers (1) provided with at least one groove (4) at least one additional layer (1 ') is provided that has no groove.

Images