EP0446665A1 - Procédé de préparation d'une ébauche à partir d'une poudre métallique ou céramique - Google Patents

Procédé de préparation d'une ébauche à partir d'une poudre métallique ou céramique Download PDF

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Publication number
EP0446665A1
EP0446665A1 EP91102390A EP91102390A EP0446665A1 EP 0446665 A1 EP0446665 A1 EP 0446665A1 EP 91102390 A EP91102390 A EP 91102390A EP 91102390 A EP91102390 A EP 91102390A EP 0446665 A1 EP0446665 A1 EP 0446665A1
Authority
EP
European Patent Office
Prior art keywords
powder
mold
binder
synthetic resin
gas
Prior art date
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.)
Ceased
Application number
EP91102390A
Other languages
German (de)
English (en)
Inventor
Heinrich Prof. Dr. Feichtinger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB Asea Brown Boveri Ltd
ABB AB
Original Assignee
ABB Asea Brown Boveri Ltd
Asea Brown Boveri AB
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ABB Asea Brown Boveri Ltd, Asea Brown Boveri AB filed Critical ABB Asea Brown Boveri Ltd
Publication of EP0446665A1 publication Critical patent/EP0446665A1/fr
Ceased legal-status Critical Current

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Classifications

    • 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
    • B22F3/12—Both compacting and sintering
    • B22F3/1208—Containers or coating used therefor
    • B22F3/125—Initially porous container
    • 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
    • B22F3/004—Filling molds with powder
    • 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
    • B22F3/10—Sintering only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B13/00—Feeding the unshaped material to moulds or apparatus for producing shaped articles; Discharging shaped articles from such moulds or apparatus
    • B28B13/02—Feeding the unshaped material to moulds or apparatus for producing shaped articles
    • B28B13/021—Feeding the unshaped material to moulds or apparatus for producing shaped articles by fluid pressure acting directly on the material, e.g. using vacuum, air pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B7/00—Moulds; Cores; Mandrels
    • B28B7/34—Moulds, cores, or mandrels of special material, e.g. destructible materials
    • B28B7/342—Moulds, cores, or mandrels of special material, e.g. destructible materials which are at least partially destroyed, e.g. broken, molten, before demoulding; Moulding surfaces or spaces shaped by, or in, the ground, or sand or soil, whether bound or not; Cores consisting at least mainly of sand or soil, whether bound or not
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B7/00—Moulds; Cores; Mandrels
    • B28B7/34—Moulds, cores, or mandrels of special material, e.g. destructible materials
    • B28B7/344—Moulds, cores, or mandrels of special material, e.g. destructible materials from absorbent or liquid- or gas-permeable materials, e.g. plaster moulds in general
    • 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
    • B22F3/10—Sintering only
    • B22F2003/1042—Sintering only with support for articles to be sintered
    • 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
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy

Definitions

  • the invention relates to the further development, perfection and simplification of powder metallurgical manufacturing methods for the production of workpieces with comparatively complicated shapes, where the problems of shrinkage during sintering play an important role.
  • the main area of application is in the area of components for turbine construction.
  • the invention relates to a method for producing a component by producing a shaped body from a free-flowing metallic or ceramic powder by spinning the powder transported by means of a gas flow onto the inner wall of a mold under reduced pressure and sintering the pre-compressed body.
  • metal injection molding In metal injection molding ("metal injection molding”; MIM), a mixture of the metal powder to be compacted is injected into a mold together with a suitable thermoplastic in accordance with the injection molding technique. A summary of the methods of "metal injection molding” is given in a chapter of the Metals Handbook.
  • the vacuum molding process is known from foundry technology and is used to produce casting molds from refractory granular molding material, usually quartz sand.
  • refractory granular molding material usually quartz sand.
  • a negative pressure is created in the sand, which exerts a compression pressure of the external gas atmosphere on the sand bed via the film.
  • the resulting compressive stresses between the grains prevent their mutual mobility, which means that a loose body creates a mechanically resistant body with a defined shape.
  • substantially dry powders are filled into a mold under vacuum.
  • This process can e.g. be supported by a suitable vibration or vibration process.
  • the complexity of the shaping is limited due to the frictional resistance of the powder, or there is a risk that the different grain fractions of a powder will separate under the influence of the powder movement, in particular under the action of vibrations, which results in an inhomogeneous sintered body.
  • a molded body is produced in such a way that a free-flowing molding compound is fluidized by means of a transport gas and in this way reaches the interior of a mold that is under negative pressure and contains suction openings at certain points for the discharge of the transport gas.
  • An essential part of the description of this method is devoted to the optimal dimensioning and arrangement of these suction openings, or the optimal timing of the blowing and suction process, since both the geometric arrangement and the timing are of great importance for the generation of a molded body with a uniform bulk density.
  • the invention has for its object to provide a method with which, starting from free-flowing metal or ceramic powders, a comparatively complicated shaped workpiece of any cross-section and unlimited wall thickness can be produced. Sufficient green strength for further processing should be achieved for the green compact.
  • the process is intended to provide a reproducible finished product that no longer has to be processed, or at most only slightly. Bubbles and unwanted harmful residues should be avoided during powder processing. With regard to the selection of the shape and the composition of the workpiece to be produced, the process is intended to ensure the greatest possible freedom of movement and universality.
  • the powder is introduced into a gas-permeable form made of a material which consists of a pile of ceramic grains which are held together by a small proportion of an essentially organically constructed binder, whereby the form is in the range between room temperature and a temperature just below the sintering temperature of the powder forming the shaped body has a high mechanical strength for the purpose of supporting the shaped body, and that the binder, in turn, its strength and in a temperature range where the shaped body achieves a sufficient inherent strength that retains its shape as a result of the sintering process so that it loses its support effect by partially or completely evaporating and / or burning in said temperature range and under the influence of the oxidizing or reducing effect of the furnace atmosphere.
  • the purpose of the invention is the production of moldings from free-flowing powders which, after being introduced into a mold, either acquire a green strength through a binder phase, so that they can be removed from the mold and fed to a sintering process, or are themselves subjected to a sintering process within this mold, the mold in this case serves as a support for the shaped body and must not react with the shaped body under the influence of the temperature, or must be removable from the surface of the shaped body after the sintering process is complete.
  • the powder from which the shaped body is constructed can be a metal or a ceramic powder or a mixture of these powders.
  • 1 shows a schematic view (viewed in the direction of flow of the gas flow) of an idealized bed of globular powder particles (hexagonally closest spherical packing).
  • 1 is an idealized globular powder particle in the densest bed (shown simply as a sphere).
  • 2 is the open-pore space between adjacent powder particles (flow channel for gas flow).
  • FIG. 2 shows an elevation / section (viewed perpendicular to the direction of flow of the gas flow) of an idealized bed of globular powder particles (hexagonally densest spherical packing) on the wall of a mold.
  • the reference number 1 is identical to that of FIG. 1.
  • 3 is a powder particle approaching perpendicular to the inside wall of the mold.
  • 4 is the gas flow perpendicular to the powder bed surface.
  • 5 represents the gas-permeable wall of the porous (open-pore) shape.
  • the entire wall 5 of the mold consists of a gas-permeable porous material, the porosity, at least in the region of the inner surface of the mold, having a pore diameter which prevents even the smallest size of powder grains from penetrating. Since the entire inner surface of the gas-permeable mold, which is under a negative pressure and is pressurized from the outside, is available for gas transport, the fluidized powder (particles) can in principle get to any point on the mold, with a uniform coating process being controlled automatically by the fact that the points the wall 5, which were coated with powder to a greater extent, represent a greater flow resistance and therefore direct further fluidized powder to those points of the wall 5 where the layer thickness is not yet as thick and therefore there is less flow resistance.
  • 3 relates to an elevation / section of a device for carrying out the method at the point in time before the mold is filled.
  • 6 is the free-flowing powder (metal, ceramic) to be processed, which is located in the storage container 7 at the beginning of the process.
  • 8 is the gas supply line for the transport gas required for the fluidization of the powder 6 to the storage container 7.
  • the storage container 7 is closed at the bottom by a bursting film 9 as a barrier element for the powder 6.
  • a vacuum container 10 is connected to the bursting film 9 with the interposition of a seal 11. This is provided with a suction line, which is connected to a vacuum pump (not shown).
  • a gas-permeable divided or undivided form 13 made of ceramic material and an organic binder.
  • 14 is the cavity (interior) of the form 13.
  • FIG. 4 shows an elevation / section of a device for carrying out the method during the filling of the mold.
  • the reference numerals 6 to 14 correspond exactly to those in FIG. 3.
  • the bursting film 9 is shown here in the broken state, where it clears the way for the powder 6 in the direction of the cavity 14 in the mold 13.
  • 15 is the powder jet (powder cloud) formed by the fluidized powder in the cavity 14.
  • 4 represents the gas flow perpendicular to the powder surface and through the wall of the mold 13.
  • 18 is the sprayed onto the inner wall of the mold 14, dynamically packed powder layer. Depending on the shape of the mold 14 and the flow conditions, this can currently have different thicknesses.
  • the essence of the invention is that the material used for the gas-permeable porous form for the powder-metallurgical / powder-ceramic production of a complicated component is a heap of ceramic grains held together at the points of contact with an organic binder based on plastic (aminoplast, phenol plastic, furan resin, water glass, synthetic resin) becomes.
  • the materials of the workpiece (component) and tool (mold) made up of powder particles behave in opposite directions: the strength and the resistance to change in shape of the workpiece decrease due to local gluing and softening and eventual sintering, while the same tool sizes decrease due to decomposition, chemical change, melting and evaporation of the binder.
  • the shape of the workpiece is preserved in the critical temperature range and its movement ability is not significantly impaired when shrinking.
  • the method for producing a component by producing a shaped body from a free-flowing metallic or ceramic powder (6) by spinning the powder (6) transported by means of a gas flow (4) onto the inner wall of a mold (13) under reduced pressure and sintering the Pre-compacted body is carried out by introducing the powder into a gas-permeable form (13) made of a material consisting of a pile of ceramic grains, which by a small proportion of an essentially organic assembled binder are held together, whereby the mold (13) in the range between room temperature and a temperature just below the sintering temperature of the powder forming the molded body has a high mechanical strength for the purpose of supporting the molded body, and that the binder in a temperature range where the molded body results of the onset sintering process achieves a sufficient inherent strength that maintains its shape, in turn loses its strength and thus its supporting effect by partially or completely evaporating and / or burning in said temperature range and under the influence of the oxidizing or reducing effect of the furnace atmosphere.
  • the organic binder consists of a synthetic resin selected from one of the groups of aminoplasts or phenolic plastics or furan resins, the sand preferably being coated warm or hot with a binder selected from the group of phenolic resins / novalaks.
  • the organic binder advantageously consists of water glass and a synthetic resin, with primary curing being carried out by fumigation with carbonic acid and final curing by thermal curing of the synthetic resin.
  • the material for the mold consists of a grained glass frit with an organic binder, which fries at higher temperatures during the release of the organic bond and then sinters tightly.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Powder Metallurgy (AREA)
  • Moulds, Cores, Or Mandrels (AREA)
EP91102390A 1990-03-14 1991-02-20 Procédé de préparation d'une ébauche à partir d'une poudre métallique ou céramique Ceased EP0446665A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH815/90 1990-03-14
CH81590 1990-03-14

Publications (1)

Publication Number Publication Date
EP0446665A1 true EP0446665A1 (fr) 1991-09-18

Family

ID=4195843

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91102390A Ceased EP0446665A1 (fr) 1990-03-14 1991-02-20 Procédé de préparation d'une ébauche à partir d'une poudre métallique ou céramique

Country Status (3)

Country Link
US (1) US5217664A (fr)
EP (1) EP0446665A1 (fr)
JP (1) JPH04224604A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6406663B1 (en) 2000-04-27 2002-06-18 Skf Nova Ab Method and apparatus for compacting a powder material into a homogenous article
DE19881759B4 (de) * 1997-11-18 2008-11-06 J. Eberspächer GmbH & Co. KG Brennkammerherstellungsverfahren sowie hiernach gefertigte Brennkammer eines Fahrzeug-Heizgeräts

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0545718A3 (en) * 1991-12-03 1993-10-13 Janome Sewing Machine Co., Ltd. Method of making bone-implants
DE69405406T2 (de) * 1993-10-29 1998-04-02 Medtronic Inc Verfahren zur herstellung von einer medizinischen stimulationselektrode
US5770136A (en) * 1995-08-07 1998-06-23 Huang; Xiaodi Method for consolidating powdered materials to near net shape and full density
US5849244A (en) * 1996-04-04 1998-12-15 Crucible Materials Corporation Method for vacuum loading
US5932256A (en) 1996-09-27 1999-08-03 Mandish; Theodore O. Vacuum molding apparatus
DE19712442C2 (de) * 1997-03-25 1999-05-12 Karlsruhe Forschzent Verfahren zur Herstellung von mikrostrukturierten keramischen Bauteilen
US6042780A (en) * 1998-12-15 2000-03-28 Huang; Xiaodi Method for manufacturing high performance components

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2076407A5 (en) * 1970-01-14 1971-10-15 Montagne Pierre Porous mould for ceramics - of glass or ceramic glass composite
DE1646585A1 (de) * 1967-07-21 1972-03-16 Hutschenreuther Verfahren zur Herstellung von zur Verarbeitung keramischer Massen dienenden Formen
FR2455940A1 (fr) * 1979-05-07 1980-12-05 Asea Ab Procede de fabrication d'objets en matiere ceramique ou metallique par pressage isostatique de poudres
DE3101236A1 (de) * 1980-01-23 1982-01-28 Eugen Dipl.-Ing. 8871 Burtenbach Bühler Verfahren zur herstellung trockengepresster formlinge und vorrichtung zur durchfuehrung dieses verfahrens
GB2187995A (en) * 1986-01-22 1987-09-23 Honda Motor Co Ltd Process for producing cylindrical reinforcing fibrous molding
CH667840A5 (en) * 1985-07-18 1988-11-15 Sulzer Ag Ceramic body production method - burns organic mould in oven to dry and fire mass contained

Family Cites Families (8)

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US2513785A (en) * 1946-04-25 1950-07-04 Dewey And Almy Chem Comp Method of manufacture of matrices and casting beds
DE3128348A1 (de) * 1981-07-17 1983-02-03 Bühler, Eugen, Dipl.-Ing., 8871 Burtenbach Einrichtung zur herstellung von formlingen aus einer rieselfaehigen masse stichwort: "vorverdichtung im schiesskopf"
GB2088414B (en) * 1980-11-24 1985-01-09 Nippon Dia Cleviteco Ltd Sintering stainless steel powder
DE3128347A1 (de) * 1981-07-17 1983-02-03 Eugen Dipl.-Ing. 8871 Burtenbach Bühler Verfahren und einrichtung zur herstellung von formlingen aus rieselfaehiger masse stichwort: "beibehaltung des fuellvakuums beim isostatischen pressen"
DE3328954C1 (de) * 1983-08-11 1985-01-31 MTU Motoren- und Turbinen-Union München GmbH, 8000 München Verfahren zur Herstellung von Formteilen durch kaltisostatisches Pressen
KR890003502B1 (ko) * 1985-02-08 1989-09-23 가부시기가이샤 히다찌세이사꾸쇼 슬립캐스팅 성형법 및 성형용 주형
JPS61273298A (ja) * 1985-05-28 1986-12-03 Nippon Kokan Kk <Nkk> 粉体の成形方法
DE3542332A1 (de) * 1985-11-29 1987-06-04 Hutschenreuther Verfahren und einrichtung zur herstellung von mit kanaelen versehenen presslingen aus pulverfoermiger formmasse, insbesondere keramischer formmasse stichwort: honeycomb

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1646585A1 (de) * 1967-07-21 1972-03-16 Hutschenreuther Verfahren zur Herstellung von zur Verarbeitung keramischer Massen dienenden Formen
FR2076407A5 (en) * 1970-01-14 1971-10-15 Montagne Pierre Porous mould for ceramics - of glass or ceramic glass composite
FR2455940A1 (fr) * 1979-05-07 1980-12-05 Asea Ab Procede de fabrication d'objets en matiere ceramique ou metallique par pressage isostatique de poudres
DE3101236A1 (de) * 1980-01-23 1982-01-28 Eugen Dipl.-Ing. 8871 Burtenbach Bühler Verfahren zur herstellung trockengepresster formlinge und vorrichtung zur durchfuehrung dieses verfahrens
CH667840A5 (en) * 1985-07-18 1988-11-15 Sulzer Ag Ceramic body production method - burns organic mould in oven to dry and fire mass contained
GB2187995A (en) * 1986-01-22 1987-09-23 Honda Motor Co Ltd Process for producing cylindrical reinforcing fibrous molding

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19881759B4 (de) * 1997-11-18 2008-11-06 J. Eberspächer GmbH & Co. KG Brennkammerherstellungsverfahren sowie hiernach gefertigte Brennkammer eines Fahrzeug-Heizgeräts
US6406663B1 (en) 2000-04-27 2002-06-18 Skf Nova Ab Method and apparatus for compacting a powder material into a homogenous article

Also Published As

Publication number Publication date
US5217664A (en) 1993-06-08
JPH04224604A (ja) 1992-08-13

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