EP0133515A2 - Process for manufacturing preforms by cold isostatic pressing - Google Patents

Process for manufacturing preforms by cold isostatic pressing Download PDF

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Publication number
EP0133515A2
EP0133515A2 EP84108782A EP84108782A EP0133515A2 EP 0133515 A2 EP0133515 A2 EP 0133515A2 EP 84108782 A EP84108782 A EP 84108782A EP 84108782 A EP84108782 A EP 84108782A EP 0133515 A2 EP0133515 A2 EP 0133515A2
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EP
European Patent Office
Prior art keywords
outer support
cold isostatic
elastic
mold
isostatic pressing
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP84108782A
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German (de)
French (fr)
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EP0133515B1 (en
EP0133515A3 (en
Inventor
Wolfgang Dr.-Ing. Betz
Werner Dr.-Ing. Hüther
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MTU Aero Engines GmbH
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MTU Motoren und Turbinen Union Muenchen GmbH
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/001—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a flexible element, e.g. diaphragm, urged by fluid pressure; Isostatic presses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B22F3/04—Compacting only by applying fluid pressure, e.g. by cold isostatic pressing [CIP]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S264/00—Plastic and nonmetallic article shaping or treating: processes
    • Y10S264/78—Processes of molding using vacuum
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S425/00—Plastic article or earthenware shaping or treating: apparatus
    • Y10S425/044—Rubber mold

Definitions

  • the present invention relates to a method for producing molded parts, in particular those with a complicated outer contour, by cold isostatic pressing, in which an impenetrable, thin-walled and elastic casing is brought into contact with the inner wall of a divisible outer support mold made of open-pore material by exposing the outer support mold to a vacuum, then filling and closing the elastic sleeve with powdered molding material and then subjecting it to a cold isostatic pressure.
  • the object of the present invention to provide a process for the production of molded parts by cold isostatic pressing of the type mentioned at the outset, in which complicated molded parts can be pressed precisely with little effort, without having to make restrictions with regard to the contour to be produced or aftertreatment being necessary would.
  • the object is achieved in that in a method according to the preamble of claim 1, after the powder has been poured in, the underpressure on the outer support mold is released and underpressure is generated in the casing, and in that the outer support mold is removed before the cold isostatic pressing.
  • the main advantage of the method according to the invention is that, in cold isostatic pressing, even the green compact is only surrounded by a thin-walled, elastic shell and therefore no restrictions need to be made with regard to the contour that can be produced.
  • the green compact has the highest dimensional stability, which is achieved by generating negative pressure in the shell prior to removal from the outer support mold.
  • the negative pressure means that the individual powder particles are no longer displaceable relative to one another and thus the contour removed from the outer support shape is maintained with the greatest accuracy.
  • This highest form of loyalty completed g epreßten molding can be achieved.
  • An advantageous embodiment of the method according to the invention is characterized in that the outer support form is accommodated in a closed container with connecting lines for generating negative or positive pressure and for filling in the powdery material. This configuration makes the method according to the invention suitable for series production.
  • the elastic sleeve has a wall thickness of 0.1 to 1 mm and, as is known per se, is formed from rubber material.
  • a particularly small wall thickness is important in the process according to the invention, since this ensures that the membrane tension in the casing remains small enough not to outweigh the pressure resulting from atmospheric pressure and powder spill when filling in the powdery material.
  • glass frit, sintered metal or porous ceramic is provided as the outer support form.
  • the device 1 comprises an outer closed container 2 with a lid 3.
  • the lid 3 has a central filling opening through which an elastic sleeve 8, which according to the drawing is a thin-walled rubber skin, extends into the interior of the container.
  • the rubber skin is closed inside the container and is located in an inner cavity which is formed by a divisible outer support form 5, 6 and 7.
  • the shaped support parts 5, 6, 7 are in turn received in a form-fitting manner in the closed container 2, 3.
  • the filler neck 9 of the elastic form 8 is connected to a connecting line via an airtight connection 12.
  • the filler neck 9 can be closed by a G ummistöpsel 10 with internal vacuum line. 11
  • the support form 5, 6, 7 consists of an open-pore material, in particular of a glass frit, of sintered metal or of porous ceramic.
  • the shape is divisible so that the green body can be removed later.
  • the parts of the support mold be positively in the container 2, 3 is assigned to e-g.
  • the connecting cables are laid.
  • the rubber mold is in the support form.
  • the elastic thin-walled envelope 8 is inflated by the air pressure, so that it bears against the inner contour of the open-pore support form.
  • the powder 13 to be compressed is filled through the filler neck 9 of the elastic shape 8 and then the filler neck 9 is closed with the rubber stopper 10, which in turn has an evacuation line 11.
  • the vacuum lines 4 are opened so that air flows into the porous support mold 5, 6, 7.
  • the air from the inflated elastic form 8 is pumped out through the evacuation opening of the rubber plug 10.
  • Atmospheric pressure now rests on the outer skin of the elastic mold 8 and thus also on the filled powder 13.
  • the friction in the powder 13 is so great that the part to be pressed no longer deforms by itself.
  • the vacuum line 11 is then closed in the stopper 10, the tool disassembled and the part encased by the rubber mold is cold isostatically pressed.
  • the invention can therefore be used to produce a complicated molded part, such as a turbine wheel with a precise outer contour, in a simple manner.
  • the invention is based on the knowledge that due to the extremely thin-walled elastic shape 8 when the cold isostatic pressure is reduced, the shape when springing up only small radially outward or axial forces on the part to be transferred. Nevertheless, the elastic shape 8 is mechanically stable enough due to the outer support parts 5, 6, 7, so that there are no changes in shape when filling the powder 13.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Press-Shaping Or Shaping Using Conveyers (AREA)
  • Powder Metallurgy (AREA)
  • Press Drives And Press Lines (AREA)

Abstract

Eine dünnwandige elastische Form wird in einer teilbaren äußeren Stützform aus offenporigem Material angeordnet und ein Vakuum an die äußere Stützform angelegt. Anschließend wird in die elastiche Form Metall- oder Keramikpulver eingefüllt und diese verschlossen. Ein derart vorbereitetes Formteil wird anschließend einem kaltisostatischen Preßdruck ausgesetzt, der an die Außenhaut der elastischen Form angelegt wird. Vor dem kaltiostatischen Pressen wird das Vakuum an der äußeren Stützform gelöst und ein Vakuum im Innern der Form elastischen erzeugt.A thin-walled elastic form is arranged in a divisible outer support form made of open-pore material and a vacuum is applied to the outer support form. Then metal or ceramic powder is poured into the elastic mold and sealed. A molded part prepared in this way is then subjected to a cold isostatic pressure which is applied to the outer skin of the elastic mold. Before the cold-static pressing, the vacuum on the outer support mold is released and a vacuum is created on the inside of the mold.

Description

Im Stand der Technik sind Verfahren zur Herstellung von Grünlingen aus Metall- oder Keramikpulver durch kaltisostatisches Pressen bekannt. Das entsprechende Pulver wird in eine elastische Form (z. B. aus Gummi) eingefüllt und durch hydrostatischen Druck (500 bis 6000 bar) verdichtet. Durch Einlegen von Kernen ist es möglich, auch eine Innenkontur herzustellen. Mit den bekannten Verfahren lassen sich komplizierte Außenkonturen z. B. Turbinenräder nicht herstellen. Dies ist darauf zurückzuführen, daß beim Abbau des Druckes die Form auffedert und noch am Formkörper anliegt. Hierdurch werden radial nach außen gerichtete, bzw. axiale Kräfte auf den Grünling übertragen, die zur Zerstörung empfindlicher, z. B. dünnwandiger Bereiche des Grünlings führen können.Methods for producing green compacts from metal or ceramic powder by cold isostatic pressing are known in the prior art. The corresponding powder is filled into an elastic mold (e.g. made of rubber) and compressed by hydrostatic pressure (500 to 6000 bar). By inserting cores it is also possible to create an inner contour. With the known methods, complicated outer contours z. B. Do not manufacture turbine wheels. This is due to the fact that when the pressure is released the mold springs open and is still in contact with the molded body. As a result, radially outward or axial forces are transmitted to the green body, which are sensitive to destruction, for. B. thin-walled areas of the green compact.

Die vorliegende Erfindung bezieht sich auf ein Verfahren zur Herstellung von Formteilen, insbesondere solchen mit komplizierter Außenkontur, durch kaltisostatisches Pressen, bei dem eine undurchdringliche, dünnwandige und elastische Hülle an der Innenwand einer teilbaren äußeren Stützform aus offenporigem Material zur Anlage gebracht indem die äußere Stützform einem Unterdruck ausgesetzt wirc wird, worauf die elastische Hülle mit pulverförmigem Formmaterial gefüllt und verschlossen wird und anschließend einem kaltisostatischen Preßdruck ausgesetzt wird.The present invention relates to a method for producing molded parts, in particular those with a complicated outer contour, by cold isostatic pressing, in which an impenetrable, thin-walled and elastic casing is brought into contact with the inner wall of a divisible outer support mold made of open-pore material by exposing the outer support mold to a vacuum, then filling and closing the elastic sleeve with powdered molding material and then subjecting it to a cold isostatic pressure.

Ein solches Verfahren ist aus der DE-OS 14 83 684 bekannt. Der Vorteil dieses Verfahrens gegenüber dem eingangs genannten Stand der Technik besteht darin, daß hohe Formtreue erzielbar ist, ohne daß der Aufwand für die Einformung selbst unvertretbar hoch ist. Die mit dem pulverförmigen Formmaterial gefüllte dünnwandige elastische Hülle hat aber keine Eigensteifigkeit, so daß die Stützform beim kaltisostatischen Preßvorgang benötigt wird, um die gewünschte Außenkontur des Formteils zu gewährleisten. Hierdurch ergeben sich jedoch in erheblichem Ausmaß Einschränkungen bezüglich der herstellbaren Außenkonturen. So sind z. B. solche Formteile mit dem vorgenannten Verfahren nicht herstellbar, die stark gekrümmte Konturen mit Hinterschneidungen aufweisen, da hierdurch beim Schwund im Verlauf des isostatischen Pressens eine Kollision mit der äußeren Stützform auftreten würde. Aber selbst dann, wenn durch den Schwund des Formteils nicht unmittelbar eine Kollision mit der äußeren Stützform zu besorgen wäre, bestünde doch die Gefahr, daß aufgrund des Nicht-Mitschwindens der äußeren Stützform Kräfte auf das zu pressende Formteil ausgeübt werden, die zur Rißbildung führen.Such a method is known from DE-OS 14 83 684. The advantage of this method over the prior art mentioned at the outset is that high dimensional accuracy can be achieved without the expenditure for the molding itself being unacceptably high. The thin-walled elastic casing filled with the powdered molding material has no inherent stiffness, so that the support mold is required during the cold isostatic pressing process in order to ensure the desired outer contour of the molded part. However, this results in considerable restrictions with regard to the outer contours that can be produced. So z. B. such molded parts can not be produced with the aforementioned method, which have strongly curved contours with undercuts, as this would cause a collision with the outer support form in the course of isostatic pressing. But even if a collision with the outer support mold were not immediately to be caused by the shrinkage of the molded part, there would still be a risk that, due to the non-collapse of the outer support mold, forces would be exerted on the molded part to be pressed, which would lead to crack formation.

Aufgabe der vorliegenden Erfindung ist es deshalb, ein Verfahren zur Herstellung von Formteilen durch kaltisostatisches Pressen der eingangs genannten Art zu schaffen, bei dem mit geringem Aufwand komplizierte Formteile präzise gepreßt werden können, ohne daß Einschränkungen bezüglich der herzustellenden Kontur gemacht werden müßten oder eine Nachbehandlung erforderlich wäre. Erfindungsgemäß wird die gestellte Aufgabe dadurch gelöst, daß bei einem Verfahren nach dem Oberbegriff des Patentanspruchs 1 nach dem Einfüllen des Pulvers der Unterdruck an der äußeren Stützform gelöst und Unterdruck in der Hülle erzeugt wird und daß vor dem kaltisostatischen Pressen die äußere Stützform entfernt wird.It is therefore an object of the present invention to provide a process for the production of molded parts by cold isostatic pressing of the type mentioned at the outset, in which complicated molded parts can be pressed precisely with little effort, without having to make restrictions with regard to the contour to be produced or aftertreatment being necessary would. According to the invention, the object is achieved in that in a method according to the preamble of claim 1, after the powder has been poured in, the underpressure on the outer support mold is released and underpressure is generated in the casing, and in that the outer support mold is removed before the cold isostatic pressing.

Der Hauptvorteil des erfindungsgemäßen Verfahren liegt darin, daß beim kaltisostatischen Pressen selbst der Grünling nur von einer dünnwandigen elastischen Hülle umgeben ist und somit hinsichtlich der erzeugbaren Kontur keinerlei Einschränkungen gemacht werden müssen. Trotz der nur dünnwandigen und elastischen Hülle weist der Grünling aber höchste Formstabilität auf, die dadurch erzielt wird, daß vor dem Herausnehmen aus der äußeren Stützform Unterdruck in der Hülle erzeugt wird.. Der Unterdruck führt dazu, daß die einzelnen Pulverteilchen gegeneinander nicht mehr verschieblich sind und somit die von der äußeren Stützform abgenommene Kontur mit größter Genauigkeit beibehalten wird. Dadurch läßt sich höchste Formtreue des fertiggepreßten Formteils erreichen. Eine vorteilhafte Ausführungsform des erfindungsgemäßen Verfahrens ist dadurch gekennzeichnet, daß die äußere Stützform in einem geschlossenen Behälter mit Anschlußleitungen zur Erzeugung von Unter- bzw. Überdruck und für das Einfüllen des pulverförmigen Materials aufgenommen ist. Durch diese Ausgestaltung eignet sich das erfindungsgemäße Verfahren für die Serienherstellung.The main advantage of the method according to the invention is that, in cold isostatic pressing, even the green compact is only surrounded by a thin-walled, elastic shell and therefore no restrictions need to be made with regard to the contour that can be produced. Despite the only thin-walled and elastic shell, the green compact has the highest dimensional stability, which is achieved by generating negative pressure in the shell prior to removal from the outer support mold. The negative pressure means that the individual powder particles are no longer displaceable relative to one another and thus the contour removed from the outer support shape is maintained with the greatest accuracy. This highest form of loyalty completed g epreßten molding can be achieved. An advantageous embodiment of the method according to the invention is characterized in that the outer support form is accommodated in a closed container with connecting lines for generating negative or positive pressure and for filling in the powdery material. This configuration makes the method according to the invention suitable for series production.

Vorteilhaft ist es, wenn die elastische Hülle eine Wandstärke von 0,1 bis 1 mm aufweist und, wie an sich bekannt, aus Gummimaterial gebildet wird. Für die Durchführung des erfindungsgemäßen Verfahren ist eine besonders geringe Wandstärke von Bedeutung, da hierdurchigewährleistet wird, daß die Membranspannunq in der Hülle klein genug bleibt, um gegen den aus Atmosphärendruck und Pulverschüttung sich erqebenden Druck beim Einfüllen des pulverförmigen Materials nicht zu überwiegen. Schließlich ist es vorteilhaft, wenn als äußere Stützform Glasfritte, Sintermetall oder poröse Keramik vorgesehen wird.It is advantageous if the elastic sleeve has a wall thickness of 0.1 to 1 mm and, as is known per se, is formed from rubber material. For the implementation A particularly small wall thickness is important in the process according to the invention, since this ensures that the membrane tension in the casing remains small enough not to outweigh the pressure resulting from atmospheric pressure and powder spill when filling in the powdery material. Finally, it is advantageous if glass frit, sintered metal or porous ceramic is provided as the outer support form.

Es hat sich gezeigt, daß das erfindungsgemäße Verfahren besonders vorteilhaft für die Herstellung eines Verdichter- oder Turbinenrades angewendet werden kann.It has been shown that the method according to the invention can be used particularly advantageously for the production of a compressor or turbine wheel.

Ein Ausführungsbeispiel des erfindungsgemäßen Verfahrens wird nachfolgend unter Bezugnahme auf die beigefügte Zeichnung erläutert: In der Zeichnung ist eine Vorrichtung 1 zur Herstellung eines Grünlings eines Radialturbinenrades für das nachfolgende kaltisostatische Pressen im Schnitt dargestellt.An embodiment of the method according to the invention is explained below with reference to the accompanying drawing: In the drawing, a device 1 for producing a green body of a radial turbine wheel for the subsequent cold isostatic pressing is shown in section.

Die Vorrichtung 1 umfaßt einen äußeren geschlossenen Behälter 2 mit einem Deckel 3. Im Boden des Behälters befinden sich Anschlußleitungen 4 für das Anlegen eines Vakuums oder eines Drucks im Innern des Behälters. Der Deckel 3 weist zentral eine Einfüllöffnung auf, durch welche eine elastische Hülle 8, die gemäß Zeichnung eine dünnwandige Gummihaut ist, in das Innere des Behälters reicht. Die Gummihaut ist im Behälterinneren geschlossen und befindet sich in einem inneren Hohlraum, der durch eine teilbare äußere Stützform 5, 6 und 7 gebildet ist. Die Stützformteile 5, 6, 7 sind ihrerseits im geschlossenen Behälter 2, 3 formschlüssig aufgenommen. Der Einfüllstutzen 9 der elastischen Form 8 ist mit einer Anschlußleitung über eine luftdichte Verbindung 12 verbunden. Der Einfüllstutzen 9 kann durch einen Gummistöpsel 10 mit innerer Vakuumleitung 11 verschlossen werden.The device 1 comprises an outer closed container 2 with a lid 3. In the bottom of the container there are connecting lines 4 for the application of a vacuum or a pressure inside the container. The lid 3 has a central filling opening through which an elastic sleeve 8, which according to the drawing is a thin-walled rubber skin, extends into the interior of the container. The rubber skin is closed inside the container and is located in an inner cavity which is formed by a divisible outer support form 5, 6 and 7. The shaped support parts 5, 6, 7 are in turn received in a form-fitting manner in the closed container 2, 3. The filler neck 9 of the elastic form 8 is connected to a connecting line via an airtight connection 12. The filler neck 9 can be closed by a G ummistöpsel 10 with internal vacuum line. 11

Die Stützform 5, 6, 7 besteht aus einem offenporigen Material, insbesondere aus einer Glasfritte, aus Sintermetall oder aus poröser Keramik. Die Form ist teilbar, damit später der Grünling entfernt werden kann. Die Teile der Stützform werden formschlüssig im Behälter 2, 3 ange-ordnet. Die Anschlußleitungen sind verlegt. In der Stützform befindet sich die Gummiform.The support form 5, 6, 7 consists of an open-pore material, in particular of a glass frit, of sintered metal or of porous ceramic. The shape is divisible so that the green body can be removed later. The parts of the support mold be positively in the container 2, 3 is assigned to e-g. The connecting cables are laid. The rubber mold is in the support form.

Wird nun das Innere der Vorrichtung 1 über die Vakuumleitungen 4 evakuiert, wird die elastische dünnwandige Hülle 8 durch den Luftdruck aufgebläht, so daß sie sich an der Innenkontur der offenporigen Stützform anlegt. Anschließend wird das zu verdichtende Pulver 13 durch den Einfüllstutzen 9 der elastischen Form 8 eingefüllt und danach der Einfüllstutzen 9 mit dem Gummistöpsel 10 verschlossen, der seinerseits eine Evakuierungsleitung 11 aufweist. Daraufhin werden die Vakuumleitungen 4 geöffnet, so daß Luft in die poröse Stützform 5, 6, 7 strömt. Die Luft aus der aufgeblähten elastischen Form 8 wird durch die Evakuierungs- öffnung des Gummistöpsels 10 abgepumpt. Nun lastet Atmosphärendruck auf der Außenhaut der elastischen Form 8 und damit auch auf dem eingefüllten Pulver 13. Die Reibung im Pulver 13 ist so groß, daß sich das zu pressende Teil nicht mehr von selbst verformt. Anschließend wird die Vakuumleitung 11 im Stöpsel 10 verschlossen, das Werkzeug zerlegt und das von der Gummiform umhüllte Teil kaltisostatisch gepreßt.If the interior of the device 1 is now evacuated via the vacuum lines 4, the elastic thin-walled envelope 8 is inflated by the air pressure, so that it bears against the inner contour of the open-pore support form. Subsequently, the powder 13 to be compressed is filled through the filler neck 9 of the elastic shape 8 and then the filler neck 9 is closed with the rubber stopper 10, which in turn has an evacuation line 11. Then the vacuum lines 4 are opened so that air flows into the porous support mold 5, 6, 7. The air from the inflated elastic form 8 is pumped out through the evacuation opening of the rubber plug 10. Atmospheric pressure now rests on the outer skin of the elastic mold 8 and thus also on the filled powder 13. The friction in the powder 13 is so great that the part to be pressed no longer deforms by itself. The vacuum line 11 is then closed in the stopper 10, the tool disassembled and the part encased by the rubber mold is cold isostatically pressed.

Durch die Erfindung kann mithin auf einfache Weise ein kompliziertes Formteil wie beispielsweise ein Turbinenrad mit präziser Außenkontur gefertigt werden. Der Erfindung liegt die Erkenntnis zugrunde, daß aufgrund der extrem dünnwandigen elastischen Form 8 beim Abbau des kaltisostatischen Preßdrucks die Form beim Auffedern nur kleine radial nach außen gerichtete bzw. axiale Kräfte auf das zu fertigende Teil überträgt. Gleichwohl ist die elastische Form 8 aufgrund der äußeren Stützteile 5, 6, 7 mechanisch stabil genug, so daß es nicht beim Einfüllen des Pulvers 13 zu Formveränderungen kommt.The invention can therefore be used to produce a complicated molded part, such as a turbine wheel with a precise outer contour, in a simple manner. The invention is based on the knowledge that due to the extremely thin-walled elastic shape 8 when the cold isostatic pressure is reduced, the shape when springing up only small radially outward or axial forces on the part to be transferred. Nevertheless, the elastic shape 8 is mechanically stable enough due to the outer support parts 5, 6, 7, so that there are no changes in shape when filling the powder 13.

Claims (6)

1. Verfahren zur Herstellung von Formteilen, insbesondere solchen mit komplizierter Außenkontur durch kaltisostatisches Pressen, bei dem eine undurchdringliche, dünnwandige und elastische Hülle an der Innenwand einer teilbaren äußeren Stützform aus offenporigem Material zur Anlage gebracht wird, indem die äußere Stützform einem Unterdruck ausgesetzt wird, worauf die elastische Hülle mit pulverförmigem Formmaterial gefüllt und verschlossen wird und anschließend einem kaltisostatischen Preßdruck ausgesetzt wird, dadurch gekennzeichnet, daß nach dem Einfüllen des Pulvers (13) der Unterdruck an der äußeren Stützform (5, 6, 7) gelöst und Unterdruck in der Hülle (8) erzeugt wird und vor dem kaltisostatischen Pressen die äußere Stützform (5, 6, 7) entfernt wird.1. A process for the production of molded parts, in particular those with a complicated outer contour by cold isostatic pressing, in which an impenetrable, thin-walled and elastic casing is brought into contact with the inner wall of a divisible outer support mold made of open-pore material by exposing the outer support mold to a negative pressure, whereupon the elastic sleeve is filled with powdered molding material and sealed and then subjected to a cold isostatic pressure, characterized in that after the powder (13) has been filled in, the negative pressure on the outer support mold (5, 6, 7) is released and negative pressure in the sleeve (8) is generated and the outer support mold (5, 6, 7) is removed before the cold isostatic pressing. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die äußere Stützform (5, 6, 7) in einem geschlossenen"Behälter (2, 3) mit Anschlußleitungen (4, 9) zur Erzeugung von Unter- bzw. überdruck und für das Einfüllen des pulverförmigen Materials (13) aufgenommen ist.2. The method according to claim 1, characterized in that the outer support form (5, 6, 7) in a closed "container (2, 3) with connecting lines (4, 9) for Generation of negative or positive pressure and for filling the powdery material (13) is added. 3. Verfahren nach den Ansprüchen 1 und 2, dadurch gekennzeichnet, daß die elastische Hülle (8) eine Wandstärke von 0,1 bis 1 mm aufweist.3. The method according to claims 1 and 2, characterized in that the elastic sleeve (8) has a wall thickness of 0.1 to 1 mm. 4. Verfahren nach den Ansprüchen 1 bis 3, dadurch gekennzeichnet, daß die elastische Hülle (8), wie an sich bekannt, aus Gummimaterial gebildet wird.4. The method according to claims 1 to 3, characterized in that the elastic sleeve (8), as known per se, is formed from rubber material. 5. Verfahren nach den Ansprüchen 1 bis 4, dadurch gekennzeichnet, daß als äußere Stützform (5, 6, 7) Glasfritte, Sintermetall oder poröse Keramik vorgesehen wird.5. The method according to claims 1 to 4, characterized in that glass frit, sintered metal or porous ceramic is provided as the outer support form (5, 6, 7). 6. Anwendung des Verfahrens nach den Ansprüchen 1 bis 5 zur Herstellung eines Verdichter- oder Turbinenrades.6. Application of the method according to claims 1 to 5 for the manufacture of a compressor or turbine wheel.
EP84108782A 1983-08-11 1984-07-25 Process for manufacturing preforms by cold isostatic pressing Expired EP0133515B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3328954A DE3328954C1 (en) 1983-08-11 1983-08-11 Process for the production of molded parts by cold isostatic pressing
DE3328954 1983-08-11

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EP0133515A2 true EP0133515A2 (en) 1985-02-27
EP0133515A3 EP0133515A3 (en) 1985-04-17
EP0133515B1 EP0133515B1 (en) 1986-10-15

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EP84108782A Expired EP0133515B1 (en) 1983-08-11 1984-07-25 Process for manufacturing preforms by cold isostatic pressing

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US (1) US4582682A (en)
EP (1) EP0133515B1 (en)
JP (1) JPS6056499A (en)
DE (2) DE3328954C1 (en)

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EP0203789A1 (en) * 1985-05-28 1986-12-03 Nippon Kokan Kabushiki Kaisha Method for molding of powders
EP0249936A2 (en) * 1986-06-17 1987-12-23 Nippon Kokan Kabushiki Kaisha Method for molding powders
EP0403743A2 (en) * 1989-06-22 1990-12-27 Nkk Corporation Method for molding powders
EP0674959A1 (en) * 1994-03-31 1995-10-04 Ngk Insulators, Ltd. Method for subjecting powder-molded material to isostatic pressing
US8173321B2 (en) 2006-06-08 2012-05-08 Daimler Ag Separator plate unit with inclined separating wall having at least one metering point and fuel cell having separator plate unit thereof

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EP0176266A1 (en) * 1984-09-04 1986-04-02 Nippon Kokan Kabushiki Kaisha Method of molding powders of metal, ceramic and the like
EP0203789A1 (en) * 1985-05-28 1986-12-03 Nippon Kokan Kabushiki Kaisha Method for molding of powders
EP0249936A2 (en) * 1986-06-17 1987-12-23 Nippon Kokan Kabushiki Kaisha Method for molding powders
US4761264A (en) * 1986-06-17 1988-08-02 Nippon Kokan Kabushiki Kaisha Method for molding powders
EP0249936A3 (en) * 1986-06-17 1989-11-15 Nippon Kokan Kabushiki Kaisha Method for molding powders
EP0403743A2 (en) * 1989-06-22 1990-12-27 Nkk Corporation Method for molding powders
EP0403743A3 (en) * 1989-06-22 1991-02-06 Nkk Corporation Method for molding powders
EP0674959A1 (en) * 1994-03-31 1995-10-04 Ngk Insulators, Ltd. Method for subjecting powder-molded material to isostatic pressing
US5828942A (en) * 1994-03-31 1998-10-27 Ngk Insulators, Ltd. Method for subjecting molded article to isostatic pressing
US8173321B2 (en) 2006-06-08 2012-05-08 Daimler Ag Separator plate unit with inclined separating wall having at least one metering point and fuel cell having separator plate unit thereof

Also Published As

Publication number Publication date
JPH0337477B2 (en) 1991-06-05
DE3328954C1 (en) 1985-01-31
EP0133515B1 (en) 1986-10-15
JPS6056499A (en) 1985-04-02
EP0133515A3 (en) 1985-04-17
DE3460940D1 (en) 1986-11-20
US4582682A (en) 1986-04-15

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