EP0554272A1 - Bindersystem und verfahren für die verarbeitung von metallpulver durch spritzgiessen - Google Patents

Bindersystem und verfahren für die verarbeitung von metallpulver durch spritzgiessen

Info

Publication number
EP0554272A1
EP0554272A1 EP91917354A EP91917354A EP0554272A1 EP 0554272 A1 EP0554272 A1 EP 0554272A1 EP 91917354 A EP91917354 A EP 91917354A EP 91917354 A EP91917354 A EP 91917354A EP 0554272 A1 EP0554272 A1 EP 0554272A1
Authority
EP
European Patent Office
Prior art keywords
binder
binder system
metal powder
polymer component
component
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.)
Withdrawn
Application number
EP91917354A
Other languages
German (de)
English (en)
French (fr)
Inventor
Wilfried Aichele
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0554272A1 publication Critical patent/EP0554272A1/de
Withdrawn legal-status Critical Current

Links

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
    • B22F3/22—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip
    • B22F3/225—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip by injection molding
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/01—Hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/05—Alcohols; Metal alcoholates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/07—Aldehydes; Ketones
    • 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
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy

Definitions

  • the invention is based on a binder system according to the type of the main claim and a method for processing metal powders into sintered parts using the binder system according to the invention.
  • MIM metal injection molding
  • Binder systems based on waxes, such as paraffin wax, are known, e.g. B. from the lecture by Chan I. Chung: Binder-Assisted Injection Molding of Powders at the Rensselaer Symposium in Troy / New York from July 16 to 18, 1990.
  • shortcomings of the wax-containing binder systems mentioned are already pointed out: low dimensional stability during thermal expulsion of the binder, long expulsion times, and a structural inhomogeneity of the green body after expulsion of the binder.
  • New binder systems have therefore been developed which consist of a polymer component and a low molecular weight binder component which is solid at room temperature and which form solutions over a wide range of temperatures and mixtures, so-called solid polymer solutions (SPS). Compared to wax-containing SPS binder systems, they have the following advantages:
  • the green bodies injection-molded therewith remain dimensionally stable while the binder is being driven out; after removal of the low-molecular component, a pore structure remains in the green compact, through which the gaseous crack products of the polymer component can escape; the low molecular weight component can be easily driven out and recovered below the melting point of the binder system.
  • PLC binder systems are e.g. B. from the above-mentioned Vorschriftmanu ⁇ script by Chan I. Chung known, for example a system of 70% acetanilide, 20 ⁇ polymer and 10 " ⁇ stearic acid.
  • the known SPS binder systems based on polystyrene or polyvinyl acetate and low molecular weight compounds such as acetanilide, diphenyl sulfone, diphenyl carbonate, antipyrine, naphthalene or decalin have the disadvantage that the low molecular weight components are harmful to health and therefore cannot be used everywhere for occupational safety reasons are.
  • the known Binder systems wetting aids such. B. stearic acid. This is necessary for the fluidity of the compounds, but it is the cause of some difficulties in the process.
  • binder systems according to the invention are based on non-toxic low molecular weight components and the polymer components are selected so that wetting aids such as, for. B. stearic acid are not necessary.
  • wetting aids such as, for. B. stearic acid are not necessary.
  • Cyclododecane, cyclododecanone, cyclododecanol or stearyl alcohol are suitable as low molecular weight components.
  • cyclododecane is used as the low molecular weight component.
  • Cyclododecane melts at 60 ° C, is largely physiologically harmless and can be removed very easily and quickly, by sublimation or by evaporation from the molding. It forms homogeneous melts with polyolefins below their solidification temperature.
  • a relatively low viscosity polypropylene can e.g. B. can be obtained by oxidative degradation of most commercially available types of polypropylene.
  • the binder system can easily be adapted for metal powders of different grain sizes and for different molded parts.
  • Polypropylenes that are oxidatively degraded in air contain polar groups. They wet the metal powders coated with an oxide skin better than unmodified polypropylenes with the same flow index. This eliminates the need to add wetting aids.
  • the binary binder system according to the invention is compounded with metal powders under protective gas in a kneader. The protective gas atmosphere during compounding prevents the oxidative dehydrogenation of the polymer component, which is catalyzed by many metal powders. When compounded in air, a partially dehydrated polypropylene would result. This results in inadmissibly high residual carbon contents when cracking under protective gas in the metal powder structure, which lead to structural defects during sintering, such as e.g. B. Carbide formation at the grain boundaries, voids and cracks due to methane formation.
  • the residual carbon content in the sintered parts can be set in a wide range as desired and z. B. lower than 0.01% if desired.
  • the pyrolysis time is therefore shorter than with the conventional temperature-time step functions.
  • the additional preheating of the incoming protective gas makes the temperature in cracking and sintering furnaces more uniform. This reduces the time required for the thermal expulsion of the binder and the distortion of filigree molded parts during sintering.
  • a commercially available type of polypropylene is oxidatively degraded by mastification at 200 ° C in air to a flow index 190 / 1.2 of 20 g per 10 minutes.
  • low-boiling degradation products escape, which form during the oxidation of additives, such as stabilizers.
  • the preparation takes place under protective gas, at 180 ° C. in a vacuum-tight SIGMA kneader, which was thoroughly rinsed with protective gas before heating.
  • the compound granulates on its own during cooling while the kneader is running.
  • the granules are processed into moldings in an extruder.
  • Sintering takes place in several stages: first heating for three hours at 120 ° C in a gentle N stream to remove the cyclododecane, heating at 120 ° C / h under N stream to 260 ° C, heating at 20 ° C / h under N stream to 330 ° C, heating at 10 ° C / h under N flow to 430 ° C, rapid heating under H flow to 1280 ° C and 1.5 hours at 1280 ° C. Parts made in this way from 430 L steel powder had densities of 98.5% of the theoretically possible density.
  • polystyrene resin In addition to polypropylenes, other polyolefins or copolymers of olefins with polar monomers in combination with cyclododecane are of course also suitable as binders for the MIM process.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Powder Metallurgy (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
EP91917354A 1990-10-25 1991-10-10 Bindersystem und verfahren für die verarbeitung von metallpulver durch spritzgiessen Withdrawn EP0554272A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4033952 1990-10-25
DE4033952A DE4033952C1 (enrdf_load_stackoverflow) 1990-10-25 1990-10-25

Publications (1)

Publication Number Publication Date
EP0554272A1 true EP0554272A1 (de) 1993-08-11

Family

ID=6417038

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91917354A Withdrawn EP0554272A1 (de) 1990-10-25 1991-10-10 Bindersystem und verfahren für die verarbeitung von metallpulver durch spritzgiessen

Country Status (4)

Country Link
EP (1) EP0554272A1 (enrdf_load_stackoverflow)
JP (1) JPH06501985A (enrdf_load_stackoverflow)
DE (1) DE4033952C1 (enrdf_load_stackoverflow)
WO (1) WO1992007675A1 (enrdf_load_stackoverflow)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4230376C1 (enrdf_load_stackoverflow) * 1992-09-11 1993-04-22 Robert Bosch Gmbh, 7000 Stuttgart, De
FR2705596B1 (fr) * 1993-05-24 1995-07-13 Impac Technologies Procédé de moulage par injection de barbotines et dispositif pour sa mise en Óoeuvre.
JPH07173503A (ja) * 1993-11-04 1995-07-11 Kobe Steel Ltd 粉末冶金用結合剤および粉末冶金用混合粉末
DE4434471C1 (de) * 1994-09-27 1996-03-28 Bosch Gmbh Robert Verfahren zur Herstellung von Formkörpern aus Hartferriten
DE102007039246A1 (de) 2007-08-20 2009-02-26 Robert Bosch Gmbh Formmasse und Verfahren zur Herstellung einer Formmasse
WO2009027837A2 (en) * 2007-08-28 2009-03-05 Corning Incorporated Method for making porous ceramic articles with fugitive pore former
EP2030957A1 (en) * 2007-08-28 2009-03-04 Corning Incorporated Fugitive pore former for porous ceramic articles
DE102011089240A1 (de) 2011-12-20 2013-06-20 Robert Bosch Gmbh Brennstoffeinspritzventil und Verfahren zur Ausformung von Abspritzöffnungen
EP4058291A4 (en) * 2019-11-15 2023-11-22 Desktop Metal, Inc. THERMAL UNBINDING TECHNIQUES FOR ADDITIVE MANUFACTURING, AND ASSOCIATED SYSTEMS AND METHODS

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3881283T2 (de) * 1987-06-25 1993-11-18 Idemitsu Petrochemical Co Metallbinder und Zusammensetzung für die Guss-Formung.
JPH0222165A (ja) * 1988-07-08 1990-01-25 Idemitsu Petrochem Co Ltd セラミックスバインダー

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9207675A1 *

Also Published As

Publication number Publication date
DE4033952C1 (enrdf_load_stackoverflow) 1992-05-27
WO1992007675A1 (de) 1992-05-14
JPH06501985A (ja) 1994-03-03

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