EP0701875A1 - Process for preparing metallic articles by injection moulding - Google Patents
Process for preparing metallic articles by injection moulding Download PDFInfo
- Publication number
- EP0701875A1 EP0701875A1 EP95113801A EP95113801A EP0701875A1 EP 0701875 A1 EP0701875 A1 EP 0701875A1 EP 95113801 A EP95113801 A EP 95113801A EP 95113801 A EP95113801 A EP 95113801A EP 0701875 A1 EP0701875 A1 EP 0701875A1
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- EP
- European Patent Office
- Prior art keywords
- molded part
- base
- injection molding
- sintering
- binder
- Prior art date
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Classifications
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- 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
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- 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
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- 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
- B22F3/1258—Container manufacturing
- B22F3/1283—Container formed as an undeformable model eliminated after consolidation
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- 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
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- 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
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- 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 present invention relates to an improved process for the production of metallic molded parts by processing an injection molding compound, wherein a.) The injection molding compound is processed into the molded part and b.) A part of the binder contained in the molded part is removed and c.) The molded part obtained in this way is sintered.
- EP-A 413 231 describes a process for producing inorganic sintered moldings.
- a deformable mass in the form of granules is produced from the sinterable powder and polyoxymethylene as a binder.
- So-called green bodies are then produced from these deformable materials by injection molding.
- the granulate is melted in injection molding machines and the melt is injected into the appropriate molds, where it cools down while the temperature drops and solidifies by falling below the glass softening temperature and / or the crystalline melting point of the binder and then is removed from the mold (page 1, line 38 to page 2 , Line 2).
- the green bodies obtained in this way are freed of most of the binder in the subsequent debinding step, whereby acid-catalytic debinding has the advantage of preventing the risk of cracking by gently removing the binder (page 2, lines 3 to 32).
- the porous parts obtained in this way are then sintered at temperatures of approximately 1100 to 1500 ° C., small amounts of residual binder possibly still escaping (page 2, lines 33 to 34).
- the method is generally very well suited for the production of inorganic sintered molded parts, however, in the case of large parts, which may have complicated shapes and / or small wall thicknesses, undesired deformations can occur during sintering.
- the sintering process requires high temperatures in order to set the desired structure in the molded body. The temperatures are usually around 1100 to 1500 ° C. At these high temperatures, however, a certain softening of the molded body to be sintered cannot be excluded. This can be undesirable, for example, in the case of cutlery items which are only incompletely supported on flat documents during the sintering process Deformations result, since the shaped body already experiences a considerable load due to its own weight.
- DE-C 4124393 discloses cutlery parts which are produced by powder metallurgical injection molding.
- a process is described in which the shaped bodies are produced essentially by the process steps of injection molding, removal of the binder and subsequent sintering of the shaped body (column 2, lines 58 to 64).
- the disadvantage there is the disadvantage that undesired deformation can occur during the sintering of the cutlery parts which have been produced by powder-metallurgical injection molding.
- the invention further relates to the molded parts obtainable by the method.
- the documents used in the method according to the invention ensure good dimensional stability of the molded part during the sintering process.
- Particularly suitable are documents which advantageously have approximately the contour of the finished molded part, have a higher creep resistance than the molded parts or do not crawl measurably in the sintering temperature range under the influence of the contact forces.
- the base can preferably be produced directly using the mold for the metallic molded part. This is the case, for example, with the spoon base.
- injection molding to create a base by injection molding, which will later serve as a base for the metallic moldings.
- the dimension of the finished sintered base can advantageously be set somewhat larger than the later molded part, so that the base has an excellent fit for the molded parts. It is advisable to dimension the base approximately 1 to 20% larger than the molded part, particularly preferably 2 to 10%.
- the measures necessary to set the dimension are known to the person skilled in the art.
- the shrinkage of the shaped body depends on the composition of the starting materials and can be varied accordingly. Furthermore, the shrinkage can be influenced by the sintering temperature, with increasing the sintering temperature a stronger shrinkage of the molded part is observed.
- a granulate is produced from sinterable metal powder, flowable binder and any auxiliary materials that may be added.
- Numerous substances are known as flowable binders. It is essential that they deliver as little residual carbon as possible when the temperature rises. Examples include polyoxymethylene, polystyrene, polymethyl methacrylate, polypropylene, polyethylene, ethylene-vinyl acetate copolymers and mixtures thereof.
- polyoxymethylene homo- or copolymers are known per se to the person skilled in the art and are described in the literature.
- the homopolymers are generally prepared by polymerizing formaldehyde or trioxane, preferably in the presence of suitable catalysts.
- Polyoxymethylene copolymers preferred in the context of the invention contain, in addition to the repeating units -OCH2-, up to 50, preferably 0.1-20 and in particular 0.3-10 mol% of repeating units.
- R1 to R4 independently of one another are a hydrogen atom, a C1-C4 alkyl group or a halogen-substituted alkyl group having 1-4 C atoms and R5 is a -CH2-, -CH2O-, one by C1-C4-alkyl or C1-C4- Haloalkyl substituted methylene group or a corresponding oxymethylene group and n has a value in the range of 0-3.
- cyclic ethers are those of the formula where R1-R5 and n have the meaning given above. Only examples include ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 1,3-butylene oxide, 1,3-dioxane, 1,3-dioxolane and dioxepane as cyclic ethers and linear oligoformals as comonomers.
- Preferred monomers of this type are ethylene diglycide, diglycidyl ether and diether from glycidylene and formaldehyde, dioxane or trioxane in a molar ratio of 2: 1 and diether from 2 mol of glycidyl compound and 1 mol of an aliphatic diol with 2-8 C atoms, such as the diglyidyl ether of ethylene glycol, 1 , 4-butanediol, 1,3-butanediol, cyclobutane-1,3-diol, 1,2-propanediol and cyclohexane-1,4-diol to name just a few examples.
- poly-1,3-oxiolane and poly-1,3-dioxepane as described, for example, in EP-A-44 475 are also suitable.
- Processes for the preparation of the homopolymers and copolymers described above are known to the person skilled in the art and are described in the literature, so that further details are unnecessary here.
- the preferred polyoxymethylene homopolymers or copolymers have melting points of at least 150 ° C. and molecular weights (weight average) in the range from 5000 to 15000, preferably from 7000 to 60,000.
- metals that can be contained in powder form only examples include iron, cobalt, nickel and silicon; Alloys are e.g. iron-based alloys such as low and high alloy steels, light metal alloys based on aluminum and titanium as well as alloys with copper or bronze. Finally, hard metals such as tungsten carbide, boron carbide or titanium nitride can also be used in combination with metals such as cobalt and nickel. The latter can be used in the production of metal-bound hard cutting tools (so-called cermets).
- Flow improvers, stabilizers or mold release agents are used as auxiliaries.
- a so-called green body is produced from the granulate in a known manner by injection molding.
- the granules are melted in injection molding machines at temperatures of about 120 to 220 ° C, preferably 170 to 200 ° C, and the melt is injected into the appropriate mold, where it cools down while the temperature drops and solidifies by falling below the glass softening temperature and / or the crystalline melting point of the binder and then removed from the mold.
- the green bodies obtained in this way are freed from a large part of the binder contained in the subsequent debinding step at temperatures of approximately 90 to 600 ° C.
- Debinding in the presence of an acid can also be recommended here, as a result of which lower temperatures are possible during debinding when the binder is acid-catalytically cleaved.
- Suitable acids are, for example, nitric acid, oxalic acid or boron trifluoride, the temperatures during the debinding are usually around 110 to 150 ° C.
- the remaining residues of the binder ensure good strength of the molded body even at the beginning of the sintering process before solidification begins by sintering on the metal particle.
- polyethylene, polypropylene, polystyrene, polymethyl methacrylate or polyvinylpyrrolidone are suitable as permanent binders.
- the proportions of the permanent binder are preferably about 0.5 to 20% by weight, particularly preferably 2 to 10% by weight, based on the total amount of binder used.
- the molded part is heated to a great extent, as a result of which the structure is changed in the desired manner and any residues of binder which are still present can be driven off.
- the molded part to be sintered is placed on a base which stabilizes the contours of the molded part.
- the temperatures during the sintering process are usually about 600 to 1600 ° C, preferably 800 to 1400 ° C, the duration usually extends from about 0.5 to 10, preferably 1 to 2 hours without heating and cooling times.
- the base should preferably be such that the molded part to be sintered not only rests at a few points, but is in contact with the base over a large area, so that good stabilization is ensured during sintering. It should be noted here that the base itself has sufficient creep stability even at the sintering temperatures.
- the method according to the invention is particularly suitable for producing thin-walled or large or complex-shaped components which, without such a support, tend to deform due to their own weight as soon as the creep resistance of the material is reduced. It thus opens up the possibility of also producing those molded parts by powder injection molding which were not previously accessible to this process because of the undesired deformation. In addition to the molded parts already listed, this is generally relevant where high dimensional accuracy is required.
- the method according to the invention can usually be used to achieve a dimensional accuracy in the finished molded parts which does not exceed about 0.5%, in special cases 0.3%, based on the predetermined value.
- cutlery items such as knives, forks, spoons as well as molded items with protruding parts that would otherwise bend slightly under their own weight.
- the method according to the invention offers a simple possibility of producing molded parts economically and inexpensively, it being possible to achieve high dimensional accuracy even of complexly shaped components with an overall high level of properties.
- the process can advantageously be integrated into existing injection molding processes for the production of metallic molded parts without great effort.
- An injection molding machine was equipped with a mold for a spoon.
- the sintered spoon is characterized by the dimensions total length 204 mm, handle length 140 mm, spoon width 44 mm, curvature of the spoon 9 mm, curvature of the handle when resting on a flat surface 12 mm, with wall thicknesses of 1 mm on the spoon part and 3 mm on the handle. Due to the expected linear sintering shrinkage of 14.5% the shape is 14.5% larger than the sintered spoon in all dimensions.
- the injection molding compound was melted at a melt temperature of 190 ° C. and injected into the mold heated to 110 ° C. After a cooling time of approx. 20 seconds, the green parts were removed from the mold.
- a mass was injected into the same mold to produce the sintered base, which consisted of 56% by volume of aluminum oxide powder with an average grain size of around 1.2 ⁇ m and 44% by volume of a binder which was 88% by weight.
- the green powder containing spoon was debindered in a nitrogen atmosphere, which contained about 1.5% concentrated nitric acid, at a temperature of 120 ° C. within 1 h.
- the sintered base was debinded in the same device in a nitrogen atmosphere, which also contained about 1.5% concentrated nitric acid, at a temperature of 130 ° C. within 2.5 h.
- the debindered sintered substrate was then heated in air at a rate of 3 ° C./min to 1.540 ° C., held at 1.540 ° C. for 2 hours and then cooled at 5 ° C./min.
- the dimensions of the non-densely sintered sintered base thus obtained are 4% larger than those of the fully sintered metal spoon.
- the spooned green part containing the unbound metal powder was placed on the sintering base and heated in a sintering furnace equipped with molybdenum heating rods under hydrogen, which had a dew point of less than -80 ° C, at a speed of 5 ° C / min to 1,300 ° C, 120 min at 1,300 ° C sintered and the sintering furnace then cooled.
- the product obtained was an exact spoon.
- the green parts obtained according to Example 1 were freed of the binder component by moving the parts at a speed of 1 ° C / min from 160 ° C to 210 ° C, at 0.5 ° C / min from 210 ° C to 250 ° C and were heated from 250 ° C to 600 ° C at 2 ° C without placing the parts on the sintered base in the shape of a spoon. After opening the debinding oven, it was found that the spherical Parts of the spoon and the handle had been placed under the influence of gravity and the arches partially collapsed.
- the green parts were placed on conventional flat aluminum oxide supports and then heated in the sintering furnace under hydrogen as in the previous example at a rate of 5 ° C./min to 1,300 ° C. and kept at 1,300 ° C. for a further 120 minutes. The furnace was then cooled and opened. The curved contours of the spoons had flattened even further.
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Abstract
Description
Die vorliegende Erfindung betrifft ein verbessertes Verfahren zur Herstellung metallischer Formteile durch Verarbeitung einer Spritzgießmasse, wobei man a.) die Spritzgießmasse zu dem Formteil verarbeitet und b.) einen Teil des im Formteil enthaltenen Bindemittels entfernt und c.) das so erhaltene Formteil sintert.The present invention relates to an improved process for the production of metallic molded parts by processing an injection molding compound, wherein a.) The injection molding compound is processed into the molded part and b.) A part of the binder contained in the molded part is removed and c.) The molded part obtained in this way is sintered.
Zur Herstellung metallischer Formteile durch Pulvermetallspritzguß sind bereits verschiedene Verfahren bekannt. In der EP-A 413 231 wird ein Verfahren zur Herstellung anorganischer Sinterformteile beschrieben. In einer ersten Stufe wird aus dem sinterbaren Pulver und Polyoxymethylen als Bindemittel eine verformbare Masse in Form von Granulaten hergestellt. Aus diesen verformbaren Massen werden anschließend durch Spritzguß sogenannte Grünkörper hergestellt. Dazu wird das Granulat in Spritzgießmaschinen aufgeschmolzen und die Schmelze in die entsprechenden Formen gespritzt, wo sie unter Temperaturerniedrigung abkühlen und durch Unterschreitung der Glaserweichungstemperatur und/oder des Kristallitschmelzpunktes des Bindemittels erstarren und anschließend aus der Form entfernt werden (Seite 1, Zeile 38 bis Seite 2, Zeile 2). Die so erhaltenen Grünkörper werden im sich anschließenden Entbinderungsschritt vom größten Teil des Bindemittels befreit, wobei eine säurekatalytische Entbinderung den Vorteil bietet, durch die schonende Entfernung des Bindemittels die Gefahr der Rißbildung zu unterbinden (Seite 2, Zeilen 3 bis 32). Die so erhaltenen, porösen Teile werden anschließend bei Temperaturen von etwa 1100 bis 1500°C gesintert, wobei ggf. noch geringe Mengen restlichen Bindemittels entweichen (Seite 2, Zeilen 33 bis 34).Various processes are already known for producing metallic molded parts by powder metal injection molding. EP-A 413 231 describes a process for producing inorganic sintered moldings. In a first stage, a deformable mass in the form of granules is produced from the sinterable powder and polyoxymethylene as a binder. So-called green bodies are then produced from these deformable materials by injection molding. For this purpose, the granulate is melted in injection molding machines and the melt is injected into the appropriate molds, where it cools down while the temperature drops and solidifies by falling below the glass softening temperature and / or the crystalline melting point of the binder and then is removed from the mold (page 1, line 38 to page 2 , Line 2). The green bodies obtained in this way are freed of most of the binder in the subsequent debinding step, whereby acid-catalytic debinding has the advantage of preventing the risk of cracking by gently removing the binder (page 2, lines 3 to 32). The porous parts obtained in this way are then sintered at temperatures of approximately 1100 to 1500 ° C., small amounts of residual binder possibly still escaping (page 2, lines 33 to 34).
Das Verfahren ist zur Herstellung anorganischer Sinterformteile im allgemeinen sehr gut geeignet, allerdings kann es beispielsweise im Falle großer Teile, welche ggf. komplizierte Formen und/oder geringe Wandstärken besitzen, beim Sintern zu unerwünschten Verformungen kommen. Der Sinterprozeß erfordert hohe Temperaturen, um das gewünschte Gefüge im Formkörper einzustellen. Üblicherweise liegen die Temperaturen bei etwa 1100 bis 1500°C. Bei diesen hohen Temperaturen kann jedoch eine gewisse Erweichung des zu sinternden Formkörpers nicht ausgeschlossen werden. Dies kann beispielsweise bei Besteckteilen, welche beim Sinterprozeß auf planen Unterlagen nur sehr unvollständig aufliegen, zu unerwünschten Verformungen führen, da der Formkörper bereits durch sein Eigengewicht eine beträchtliche Belastung erfährt.The method is generally very well suited for the production of inorganic sintered molded parts, however, in the case of large parts, which may have complicated shapes and / or small wall thicknesses, undesired deformations can occur during sintering. The sintering process requires high temperatures in order to set the desired structure in the molded body. The temperatures are usually around 1100 to 1500 ° C. At these high temperatures, however, a certain softening of the molded body to be sintered cannot be excluded. This can be undesirable, for example, in the case of cutlery items which are only incompletely supported on flat documents during the sintering process Deformations result, since the shaped body already experiences a considerable load due to its own weight.
In der DE-C 4124393 werden Besteckteile offenbart, welche durch pulvermetallurgisches Spritzgießen hergestellt werden. Auch hier wird ein Verfahren beschrieben, bei dem die Formkörper im wesentlichen durch die Verfahrensschritte Spritzgießen, Entfernung des Bindemittels und anschließende Sinterung des Formkörpers hergestellt werden (Spalte 2, Zeilen 58 bis 64). Auch hier ergibt sich der Nachteil, daß es bei der Sinterung der Besteckteile, welche durch pulvermetallurgisches Spritzgießen hergestellt worden sind, zu einer unerwünschten Verformung kommen kann.DE-C 4124393 discloses cutlery parts which are produced by powder metallurgical injection molding. Here, too, a process is described in which the shaped bodies are produced essentially by the process steps of injection molding, removal of the binder and subsequent sintering of the shaped body (column 2, lines 58 to 64). Here too there is the disadvantage that undesired deformation can occur during the sintering of the cutlery parts which have been produced by powder-metallurgical injection molding.
Es stellte sich somit die Aufgabe, ein wirtschaftliches und kostengünstiges Verfahren zu finden, daß den genannten Nachteilen abhilft und welches auch im Falle dünnwandiger bzw. kompliziert geformter Formteile zu Produkten von hoher und gleichmäßiger Qualität führt.It was therefore the task of finding an economical and inexpensive process which remedies the disadvantages mentioned and which, even in the case of thin-walled or complicatedly shaped molded parts, leads to products of high and uniform quality.
Demgemäß wurde ein Verfahren zur Herstellung eines metallischen Formteiles durch Verarbeitung einer Spritzgießmasse gefunden, wobei man
- a. die Spritzgießmasse zu dem Formteil verarbeitet und
- b. einen Teil des im Formteil enthaltenen Bindemittels bei einer Temperatur von 90 bis 600°C entfernt und
- c. das so erhaltene Formteil sintert,
- a. the injection molding compound processed into the molded part and
- b. removed a part of the binder contained in the molding at a temperature of 90 to 600 ° C and
- c. the molded part thus obtained sinters,
Weiterhin betrifft die Erfindung die mit dem Verfahren erhältlichen Formteile.The invention further relates to the molded parts obtainable by the method.
Die bei dem erfindungsgemäßen Verfahren eingesetzten Unterlagen gewährleisten während des Sinterprozesses eine gute Formstabilität des Formteils. Besonders eignen sich Unterlagen, welche vorteilhafterweise annähernd die Kontur des fertigen Formteils aufweisen, eine höhere Kriechbeständigkeit besitzen als die Formteile oder im Sintertemperaturbereich unter dem Einfluß der Auflagekräfte nicht meßbar kriechen.The documents used in the method according to the invention ensure good dimensional stability of the molded part during the sintering process. Particularly suitable are documents which advantageously have approximately the contour of the finished molded part, have a higher creep resistance than the molded parts or do not crawl measurably in the sintering temperature range under the influence of the contact forces.
Es können verschiedene Werkstoffe für die Unterlagen eingesetzt werden. Bei der Verwendung metallischer Werkstoffe ist zu beachten, daß es während des Sinterprozesses nicht zu einer unerwünschten Versinterung zwischen Formteil und Unterlage kommt. Dies kann jedoch durch verschiedene Maßnahmen, wie beispielsweise die Beschichtung der Unterlage mit inerten Pulvern wie Borcarbid, Bornitrid oder α-Aluminiumoxid vermieden werden. Besonders gut eignen sich keramische Materialien wie beispielsweise gesintertes Aluminiumoxid, Zirkondioxid, Siliziumcarbid, Aluminiumnitrid, Borcarbid oder Bornitrid.Different materials can be used for the documents. When using metallic materials, it should be noted that there is no undesired sintering between the molded part and the base during the sintering process. However, this can be avoided by various measures, such as coating the base with inert powders such as boron carbide, boron nitride or α-aluminum oxide. Ceramic materials such as sintered aluminum oxide, zirconium dioxide, silicon carbide, aluminum nitride, boron carbide or boron nitride are particularly suitable.
Die Herstellung der Unterlage kann bei einigen Formteilen bevorzugt direkt unter Verwendung der Form für das metallische Formteil erfolgen. Dies ist beispielsweise bei der Unterlage zur Herstellung von Löffeln der Fall. Hier kann man unter Verwendung der Form eine Unterlage durch Spritzguß erzeugen, welche später als Unterlage für die metallischen Formteile dient. Dabei kann man vorteilhafterweise die Dimension der fertiggesinterten Unterlage etwas größer als das spätere Formteil einstellen, sodaß die Unterlage eine ausgezeichnete Paßform für die Formteile besitzt. Es empfiehlt sich hierbei, die Unterlage etwa 1 bis 20 % größer zu dimensionieren als das Formteil, besonders bevorzugt 2 bis 10 %. Die zur Einstellung der Dimension notwendigen Maßnahmen sind dem Fachmann bekannt. So ist beispielsweise das Schwinden des Formkörpers von der Zusammensetzung der Einsatzstoffe abhängig und kann entsprechend variiert werden. Weiterhin kann durch die Sintertemperatur Einfluß auf das Schwinden genommen werden, mit Erhöhung der Sintertemperatur wird ein stärkeres Schwinden des Formteils beobachtet.In some molded parts, the base can preferably be produced directly using the mold for the metallic molded part. This is the case, for example, with the spoon base. Here you can use injection molding to create a base by injection molding, which will later serve as a base for the metallic moldings. The dimension of the finished sintered base can advantageously be set somewhat larger than the later molded part, so that the base has an excellent fit for the molded parts. It is advisable to dimension the base approximately 1 to 20% larger than the molded part, particularly preferably 2 to 10%. The measures necessary to set the dimension are known to the person skilled in the art. For example, the shrinkage of the shaped body depends on the composition of the starting materials and can be varied accordingly. Furthermore, the shrinkage can be influenced by the sintering temperature, with increasing the sintering temperature a stronger shrinkage of the molded part is observed.
Im folgenden wird das Verfahren zur Herstellung metallischer Formteile schematisch näher beschrieben.The process for the production of metallic molded parts is described schematically below.
In bekannter Art und Weise wird aus sinterbarem Metallpulver, fließfähigem Bindemittel und ggf. noch beigefügten Hilfsmitteln ein Granulat hergestellt. Als fließfähige Bindemittel sind zahlreiche Stoffe bekannt. Wesentlich ist, daß sie bei Temperaturerhöhung möglichst wenig Restkohlenstoff liefern. Beispielsweise genannt werden Polyoxymethylen, Polystyrol, Polymethylmethacrylat, Polypropylen, Polyethylen, Ethylen-Vinylacetat-Copolymere sowie deren Mischungen.In a known manner, a granulate is produced from sinterable metal powder, flowable binder and any auxiliary materials that may be added. Numerous substances are known as flowable binders. It is essential that they deliver as little residual carbon as possible when the temperature rises. Examples include polyoxymethylene, polystyrene, polymethyl methacrylate, polypropylene, polyethylene, ethylene-vinyl acetate copolymers and mixtures thereof.
Die Polyoxymethylenhomo- oder -copolymerisate sind dem Fachmann an sich bekannt und in der Literatur beschrieben.The polyoxymethylene homo- or copolymers are known per se to the person skilled in the art and are described in the literature.
Die Homopolymeren werden im allgemeinen durch Polymerisation von Formaldehyd oder Trioxan hergestellt, vorzugsweise in der Gegenwart von geeigneten Katalysatoren.The homopolymers are generally prepared by polymerizing formaldehyde or trioxane, preferably in the presence of suitable catalysts.
Im Rahmen der Erfindung bevorzugte Polyoxymethylencopolymere enthalten neben den wiederkehrenden Einheiten -OCH₂- noch bis zu 50, vorzugsweise 0,1-20 und insbesondere 0,3-10 mol-% an wiederkehrenden Einheiten.
wobei R¹ bis R⁴ unabhängig voneinander ein Wasserstoffatom, eine C₁-C₄-Alkylgruppe oder eine halogensubstituierte Alkylgruppe mit 1-4 C-Atomen und R⁵ eine -CH₂-, -CH₂O-, eine durch C₁-C₄-Alkyl- oder C₁-C₄-Haloalkyl substituierte Methylengruppe oder eine entsprechende Oxymethylengruppe darstellen und n einen Wert im Bereich von 0-3 hat. Vorteilhafterweise können diese Gruppen durch Ringöffnung von cyclischen Ethern in die Copolymere eingeführt werden. Bevorzugte cyclische Ether sind solche der Formel
wobei R¹-R⁵ und n die oben genannte Bedeutung haben. Nur beispielsweise seien Ethylenoxid, 1,2-Propylenoxid, 1,2-Butylenoxid, 1,3-Butylenoxid, 1,3-Dioxan, 1,3-Dioxolan und Dioxepan als cyclische Ether genannt sowie lineare Oligoformale als Comonomere genannt.Polyoxymethylene copolymers preferred in the context of the invention contain, in addition to the repeating units -OCH₂-, up to 50, preferably 0.1-20 and in particular 0.3-10 mol% of repeating units.
where R¹ to R⁴ independently of one another are a hydrogen atom, a C₁-C₄ alkyl group or a halogen-substituted alkyl group having 1-4 C atoms and R⁵ is a -CH₂-, -CH₂O-, one by C₁-C₄-alkyl or C₁-C₄- Haloalkyl substituted methylene group or a corresponding oxymethylene group and n has a value in the range of 0-3. These groups can advantageously be introduced into the copolymers by ring opening of cyclic ethers. Preferred cyclic ethers are those of the formula
where R¹-R⁵ and n have the meaning given above. Only examples include ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 1,3-butylene oxide, 1,3-dioxane, 1,3-dioxolane and dioxepane as cyclic ethers and linear oligoformals as comonomers.
Ebenfalls geeignet sind Oxymethylenterpolymerisate, die beispielsweise durch Umsetzung von Trioxan, einem der vorstehend beschriebenen cyclischen Ether und einem dritten Monomeren, vorzugsweise einer bifunktionellen Verbindung der Formel
wobei Z eine chemische Bindung, -O- oder -ORO- (R = C₁-C₈-Alkylen oder C₃-C₈-Cycloalkylen) ist, hergestellt wird.Also suitable are oxymethylene terpolymers, for example by reacting trioxane, one of the cyclic ethers described above and a third monomer, preferably a bifunctional compound of the formula
where Z is a chemical bond, -O- or -ORO- (R = C₁-C₈-alkylene or C₃-C₈-cycloalkylene) is produced.
Bevorzugte Monomere dieser Art sind Ethylendiglycid, Diglycidylether und Diether aus Glycidylen und Formaldehyd, Dioxan oder Trioxan im Molverhältnis 2:1 sowie Diether aus 2 mol Glycidylverbindung und 1 mol eines aliphatischen Diols mit 2-8 C-Atomen wie beispielsweise die Diglyidylether von Ethylenglykol, 1,4-Butandiol, 1,3-Butandiol, Cyclobutan-1,3-diol, 1,2-Propandiol und Cyclohexan-1,4-diol um nur einige Beispiele zu nennen.Preferred monomers of this type are ethylene diglycide, diglycidyl ether and diether from glycidylene and formaldehyde, dioxane or trioxane in a molar ratio of 2: 1 and diether from 2 mol of glycidyl compound and 1 mol of an aliphatic diol with 2-8 C atoms, such as the diglyidyl ether of ethylene glycol, 1 , 4-butanediol, 1,3-butanediol, cyclobutane-1,3-diol, 1,2-propanediol and cyclohexane-1,4-diol to name just a few examples.
Neben den Polyoxymethylenhomo- und Copolymeren sind auch Poly-1,3-oxiolan und Poly-1,3-dioxepan wie beispielsweise in der EP-A-44 475 beschrieben, geeignet. Verfahren zur Herstellung der vorstehend beschriebenen Homo- und Copolymerisate sind dem Fachmann bekannt und in der Literatur beschrieben, so daß sich hier nähere Angaben erübrigen.In addition to the polyoxymethylene homo- and copolymers, poly-1,3-oxiolane and poly-1,3-dioxepane as described, for example, in EP-A-44 475 are also suitable. Processes for the preparation of the homopolymers and copolymers described above are known to the person skilled in the art and are described in the literature, so that further details are unnecessary here.
Die bevorzugten Polyoxymethylenhomo- bzw. Copolymerisate haben Schmelzpunkte von mindestens 150°C und Molekulargewichte (Gewichtsmittelwert) im Bereich von 5000 bis 15000, vorzugsweise von 7000 bis 60000.The preferred polyoxymethylene homopolymers or copolymers have melting points of at least 150 ° C. and molecular weights (weight average) in the range from 5000 to 15000, preferably from 7000 to 60,000.
Als Metalle, die in Pulverform enthalten sein können, seien nur beispielsweise Eisen, Cobalt, Nickel und Silizium genannt; Legierungen sind z.B. eisenbasierte Legierungen wie niedrig- und hochlegierte Stähle, Leichtmetallegierungen auf der Basis von Aluminium und Titan sowie legierungen mit Kupfer oder Bronze. Schließlich kommen auch Hartmetalle wie Wolframcarbid, Borcarbid oder Titannitrid in Kombination mit Metallen wie Cobalt und Nickel in Betracht. Letztere können bei der Herstellung von metallgebundenen Hartschneidwerkzeugen (sog. Cermets) eingesetzt werden.As metals that can be contained in powder form, only examples include iron, cobalt, nickel and silicon; Alloys are e.g. iron-based alloys such as low and high alloy steels, light metal alloys based on aluminum and titanium as well as alloys with copper or bronze. Finally, hard metals such as tungsten carbide, boron carbide or titanium nitride can also be used in combination with metals such as cobalt and nickel. The latter can be used in the production of metal-bound hard cutting tools (so-called cermets).
Als Hilfsmittel werden beispielsweise Fließverbesserer, Stabilisatoren oder Entformungshilfsmittel eingesetzt.Flow improvers, stabilizers or mold release agents are used as auxiliaries.
Aus dem Granulat wird durch Spritzguß in bekannter Weise ein sogenannter Grünkörper hergestellt. Dazu wird das Granulat in Spritzgießmaschinen bei Temperaturen von etwa 120 bis 220°C, bevorzugt 170 bis 200°C aufgeschmolzen und die Schmelze in die entsprechende Form gespritzt, wo sie unter Temperaturerniedrigung abkühlt und durch Unterschreitung der Glaserweichungstemperatur und/oder des Kristallitschmelzpunktes des Bindemittels erstarrt und anschließend aus der Form entfernt wird.A so-called green body is produced from the granulate in a known manner by injection molding. For this purpose, the granules are melted in injection molding machines at temperatures of about 120 to 220 ° C, preferably 170 to 200 ° C, and the melt is injected into the appropriate mold, where it cools down while the temperature drops and solidifies by falling below the glass softening temperature and / or the crystalline melting point of the binder and then removed from the mold.
Die so erhaltenen Grünkörper werden im anschließenden Entbinderungsschritt bei Temperaturen von etwa 90 bis 600°C von einem großen Teil des enthaltenen Bindemittels befreit. Hierbei kann sich auch eine Entbinderung in Gegenwart einer Säure empfehlen, wodurch bei säurekatalytischer Spaltung des Bindemittels niedrigere Temperaturen während der Entbinderung ermöglicht werden. Geeignete Säuren sind beispielsweise Salpetersäure, Oxalsäure oder Bortrifluorid, die Temperaturen während der Entbinderung liegen hier üblicherweise bei etwa 110 bis 150°C.The green bodies obtained in this way are freed from a large part of the binder contained in the subsequent debinding step at temperatures of approximately 90 to 600 ° C. Debinding in the presence of an acid can also be recommended here, as a result of which lower temperatures are possible during debinding when the binder is acid-catalytically cleaved. Suitable acids are, for example, nitric acid, oxalic acid or boron trifluoride, the temperatures during the debinding are usually around 110 to 150 ° C.
Es kann sich besonders empfehlen, bereits zu Beginn des Prozesses ein weiteres permanentes Bindemittel in geringen Mengen hinzuzufügen, welches bei der säurekatalytischen Entbindung nicht entfernt wird.It may be particularly advisable to add another permanent binder in small quantities at the beginning of the process, which is not removed during acid catalytic debinding.
Die so verbleibenden Reste des Bindemittels gewährleisten eine gute Festigkeit des Formkörpers auch zu Beginn des Sinterprozesses, bevor eine Verfestigung über das Ansintern des Metallpartikels einsetzt.The remaining residues of the binder ensure good strength of the molded body even at the beginning of the sintering process before solidification begins by sintering on the metal particle.
Als permanente Bindemittel eignen sich beispielsweise Polyethylen, Polypropylen, Polystyrol, Polymethylmethacrylat oder Polyvinylpyrrolidon.For example, polyethylene, polypropylene, polystyrene, polymethyl methacrylate or polyvinylpyrrolidone are suitable as permanent binders.
Die Anteile des permanenten Bindemittels betragen bevorzugt etwa 0,5 bis 20 Gew.-%, besonders bevorzugt 2 bis 10 Gew.-%, bezogen auf das gesamt eingesetzte Bindemittel.The proportions of the permanent binder are preferably about 0.5 to 20% by weight, particularly preferably 2 to 10% by weight, based on the total amount of binder used.
In dem sich anschließenden Sinterprozess wird das Formteil stark erhitzt, wodurch das Gefüge in gewünschter Art und Weise verändert wird und ggf. noch verbleibende Reste enthaltenen Bindemittels ausgetrieben werden können. Hierzu wird das zu sinternde Formteil auf eine die Konturen des Formteils stabilisierende Unterlage gebracht. Die Temperaturen während des Sinterprozesses liegen üblicherweise bei etwa 600 bis 1600°C, bevorzugt 800 bis 1400°C, die Dauer erstreckt sich üblicherweise von etwa 0,5 bis 10, bevorzugt 1 bis 2 Stunden ohne Aufheiz- und Abkühlzeiten.In the subsequent sintering process, the molded part is heated to a great extent, as a result of which the structure is changed in the desired manner and any residues of binder which are still present can be driven off. For this purpose, the molded part to be sintered is placed on a base which stabilizes the contours of the molded part. The temperatures during the sintering process are usually about 600 to 1600 ° C, preferably 800 to 1400 ° C, the duration usually extends from about 0.5 to 10, preferably 1 to 2 hours without heating and cooling times.
Die Unterlage sollte dabei bevorzugt so beschaffen sein, daß das zu sinternde Formteil nicht nur an wenigen Punkten aufliegt, sondern großflächig in Kontakt mit der Unterlage steht, sodaß eine gute Stabilisierung während des Sinterns gewährleistet ist. Hierbei ist zu beachten, daß die Unterlage selber bei den Sintertemperaturen eine ausreichende Kriechstabilität aufweist.The base should preferably be such that the molded part to be sintered not only rests at a few points, but is in contact with the base over a large area, so that good stabilization is ensured during sintering. It should be noted here that the base itself has sufficient creep stability even at the sintering temperatures.
Das erfindungsgemäße Verfahren eignet sich besonders zur Herstellung dünnwandiger bzw. großer oder komplex geformter Bauteile, welche ohne eine solche Abstützung bereits durch ihr Eigengewicht zu Verformung neigen, sobald die Kriechbeständigkeit des Werkstoffes reduziert wird. Somit eröffnet es die Möglichkeit, auch solche Formteile durch Pulverspritzguß herzustellen, welche bisher diesem Verfahren wegen der unerwünschten Verformung nicht zugänglich waren. Dies ist neben den bereits aufgeführten Formteilen allgemein dort von Relevanz, wo eine hohe Maßgenauigkeit erfordert wird. Üblicherweise kann man mit Hilfe des erfindungsgemäßen Verfahrens eine Maßgenauigkeit bei den fertigen Formteilen erzielen, welche etwa 0,5 %, in besonderen Fällen 0,3 % bezogen auf den vorgegebenen Wert nicht überschreitet.The method according to the invention is particularly suitable for producing thin-walled or large or complex-shaped components which, without such a support, tend to deform due to their own weight as soon as the creep resistance of the material is reduced. It thus opens up the possibility of also producing those molded parts by powder injection molding which were not previously accessible to this process because of the undesired deformation. In addition to the molded parts already listed, this is generally relevant where high dimensional accuracy is required. The method according to the invention can usually be used to achieve a dimensional accuracy in the finished molded parts which does not exceed about 0.5%, in special cases 0.3%, based on the predetermined value.
Als Beispiele genannt werden Besteckteile wie Messer, Gabel, Löffel sowie Formkörper mit ausladenden Teilen, die sonst unter ihrem Eigengewicht leicht abknicken.Examples of cutlery items such as knives, forks, spoons as well as molded items with protruding parts that would otherwise bend slightly under their own weight.
Das erfindungsgemäße Verfahren bietet eine einfache Möglichkeit, Formteile wirtschaftlich und kostengünstig herzustellen, wobei eine hohe Maßgenauigkeit auch komplex geformter Bauteile mit insgesamt hohen Eigenschaftsniveau erzielt werden kann. Dabei kann das Verfahren vorteilhafterweise ohne größeren Aufwand in bereits vorhandene Spritzgießverfahren zur Herstellung metallischer Formteile eingebunden werden.The method according to the invention offers a simple possibility of producing molded parts economically and inexpensively, it being possible to achieve high dimensional accuracy even of complexly shaped components with an overall high level of properties. The process can advantageously be integrated into existing injection molding processes for the production of metallic molded parts without great effort.
In einem auf 185°C beheizten, evakuierbaren Kneter werden 10.080 g eines Edelstahlpulvers des Typs 316 L in Argon verdüst, mit einer mittleren Korngröße von 22 µm, 886,5 g eines Polyoxymethylens mit dem Schmelzindex 50 g/10 min bei 190°C, 98,5 g eines Polyethylens mit einem Schmelzindex von 42 g/10 min bei 190°C sowie 500 g Butylglykol als Lösungsmittel für die Binderkomponente gemischt. Nachdem eine homogene Mischung erhalten war, wurde der Kneter evakuiert und unter weiteren Kneten das Lösungsmittel abdestilliert. Danach wurde der Kneter auf 100°C abgekühlt, wobei sich die Masse verfestigte und dabei granuliert wurde. Die so erhaltene Spritzgießmasse enthielt 63 Vol.-% des Edelstahlpulvers.10.080 g of a stainless steel powder of the type 316 L in argon, with an average particle size of 22 μm, 886.5 g of a polyoxymethylene with a melt index of 50 g / 10 min at 190 ° C. are atomized in an evacuable kneader heated to 185 ° C. 98.5 g of a polyethylene with a melt index of 42 g / 10 min at 190 ° C and 500 g of butyl glycol as a solvent for the binder component. After a homogeneous mixture was obtained, the kneader was evacuated and the solvent was distilled off with further kneading. The kneader was then cooled to 100 ° C., the mass solidifying and being granulated. The injection molding composition thus obtained contained 63% by volume of the stainless steel powder.
Eine Spritzgießmaschine wurde mit einer Form für einen Löffel ausgerüstet. Der gesinterte Löffel wird gekennzeichnet durch die Dimensionen Gesamtlänge 204 mm, Stiellänge 140 mm, Löffelbreite 44 mm, Wölbung des Löffels 9 mm, Wölbung des Stiels bei Auflage auf ebener Unterlage 12 mm, bei Wandstärken von 1 mm am Löffelteil und 3 mm am Stiel. Aufgrund des zu erwartenden linearen Sinterschrumpfs von 14,5 % ist die Form in allen Maßen 14,5 % größer als der gesinterte Löffel. Die Spritzgießmasse wurde bei einer Massetemperatur von 190°C aufgeschmolzen und in die auf 110°C temperierte Form gespritzt. Nach einer Abkühlzeit von ca. 20 sec wurden die Grünteile der Form entnommen.An injection molding machine was equipped with a mold for a spoon. The sintered spoon is characterized by the dimensions total length 204 mm, handle length 140 mm, spoon width 44 mm, curvature of the spoon 9 mm, curvature of the handle when resting on a flat surface 12 mm, with wall thicknesses of 1 mm on the spoon part and 3 mm on the handle. Due to the expected linear sintering shrinkage of 14.5% the shape is 14.5% larger than the sintered spoon in all dimensions. The injection molding compound was melted at a melt temperature of 190 ° C. and injected into the mold heated to 110 ° C. After a cooling time of approx. 20 seconds, the green parts were removed from the mold.
In die gleiche Form wurde zur Herstellung der Sinterunterlage eine Masse gespritzt, die zu 56 Vol.-% aus Aluminiumoxidpulver mit einer mittleren Korngröße um 1,2 µm und zu 44 Vol.-% aus einem Binder bestand, der sich zu 88 Gew.-% aus einem Polyoxymethylen, Schmelzindex 50 g/10 min bei 190°C und zu 12 Gew.-% aus einem Polybutandiolformal mit einer mittleren Molmasse um 60.000 zusammensetzte.A mass was injected into the same mold to produce the sintered base, which consisted of 56% by volume of aluminum oxide powder with an average grain size of around 1.2 µm and 44% by volume of a binder which was 88% by weight. % of a polyoxymethylene, melt index 50 g / 10 min at 190 ° C and 12 wt .-% composed of a polybutanediol formal with an average molecular weight around 60,000.
Das Metallpulver enthaltende Löffelgrünteil wurde in einer Stickstoffatmosphäre, die ca. 1,5 % konzentrierte Salpetersäure enthielt, bei einer Temperatur von 120°C innerhalb von 1 h entbindert.The green powder containing spoon was debindered in a nitrogen atmosphere, which contained about 1.5% concentrated nitric acid, at a temperature of 120 ° C. within 1 h.
Die Sinterunterlage wurde in der gleichen Vorrichtung in einer Stickstoffatmosphäre, die ebenfalls ca. 1,5 % konzentrierte Salpetersäure enthielt, bei einer Temperatur von 130°C innerhalb von 2,5 h entbindert. Daraufhin wurde die entbinderte Sinterunterlage unter Luft mit einer Geschwindigkeit von 3°C/min auf 1,540°C aufgeheizt, 2 Stunden auf 1,540°C gehalten und dann mit 5°C/min abgekühlt.The sintered base was debinded in the same device in a nitrogen atmosphere, which also contained about 1.5% concentrated nitric acid, at a temperature of 130 ° C. within 2.5 h. The debindered sintered substrate was then heated in air at a rate of 3 ° C./min to 1.540 ° C., held at 1.540 ° C. for 2 hours and then cooled at 5 ° C./min.
Die Maße der so erhaltenen nicht dicht gesinterten Sinterunterlage sind um 4 % größer als die des fertig gesinterten Metalllöffels.The dimensions of the non-densely sintered sintered base thus obtained are 4% larger than those of the fully sintered metal spoon.
Das entbinderte Metallpulver enthaltende Löffelgrünteil wurde auf die Sinterunterlage gelegt und in einem mit Molybdänheizstäben ausgerüsteten Sinterofen unter Wasserstoff, der einen Taupunkt von weniger als -80°C aufwies mit einer Geschwindigkeit von 5°C/min auf 1,300°C aufgeheizt, 120 min bei 1,300°C gesintert und der Sinterofen dann abgekühlt. Als Produkt wurde ein exakt maßgetreuer Löffel erhalten.The spooned green part containing the unbound metal powder was placed on the sintering base and heated in a sintering furnace equipped with molybdenum heating rods under hydrogen, which had a dew point of less than -80 ° C, at a speed of 5 ° C / min to 1,300 ° C, 120 min at 1,300 ° C sintered and the sintering furnace then cooled. The product obtained was an exact spoon.
Die nach Beispiel 1 erhaltenen Grünteile wurden von der Binderkomponente befreit, indem die Teile mit einer Geschwindigkeit von 1°C/min von 160°C bis 210°C, mit 0,5°C/min von 210°C auf 250°C und mit 2°C von 250°C auf 600°C aufgeheizt wurden, ohne die Teile auf die Sinterunterlage in Löffelform zu legen. Nach dem öffnen des Entbinderungsofens wurde festgestellt, daß sich die sphärischen Teile von Löffel und Stiel dem Einfluß der Schwerkraft entsprechend gesetzt hatten und die Wölbungen teilweise eingefallen werden.The green parts obtained according to Example 1 were freed of the binder component by moving the parts at a speed of 1 ° C / min from 160 ° C to 210 ° C, at 0.5 ° C / min from 210 ° C to 250 ° C and were heated from 250 ° C to 600 ° C at 2 ° C without placing the parts on the sintered base in the shape of a spoon. After opening the debinding oven, it was found that the spherical Parts of the spoon and the handle had been placed under the influence of gravity and the arches partially collapsed.
Die Grünteile wurden auf übliche flache Aluminiumoxid-Unterlagen gelegt und dann im Sinteröfen unter Wasserstoff wie im vorigen Beispiel mit einer Geschwindigkeit von 5°C/min auf 1,300°C erhitzt und weitere 120 min bei 1,300°C gehalten. Danach wurde der Ofen abgekühlt und geöffnet. Die geschwungenen Konturen der Löffel hatten sich noch weiter abgeflacht.The green parts were placed on conventional flat aluminum oxide supports and then heated in the sintering furnace under hydrogen as in the previous example at a rate of 5 ° C./min to 1,300 ° C. and kept at 1,300 ° C. for a further 120 minutes. The furnace was then cooled and opened. The curved contours of the spoons had flattened even further.
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EP0633440A1 (en) * | 1993-07-02 | 1995-01-11 | Abb Research Ltd. | Process for preparing a setter |
-
1995
- 1995-09-02 ES ES95113801T patent/ES2146686T3/en not_active Expired - Lifetime
- 1995-09-02 DE DE59508447T patent/DE59508447D1/en not_active Expired - Lifetime
- 1995-09-02 EP EP95113801A patent/EP0701875B1/en not_active Expired - Lifetime
- 1995-09-12 JP JP7234365A patent/JPH0881701A/en active Pending
- 1995-09-13 US US08/527,682 patent/US5737683A/en not_active Expired - Lifetime
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FR2190765A1 (en) * | 1972-05-16 | 1974-02-01 | Lucas Industries Ltd | |
EP0413231A2 (en) | 1989-08-16 | 1991-02-20 | BASF Aktiengesellschaft | Process for the production of an inorganic sintered body |
EP0451467A1 (en) * | 1990-03-14 | 1991-10-16 | Asea Brown Boveri Ag | Sintering method using a yielding ceramic mould |
EP0524710A2 (en) * | 1991-07-23 | 1993-01-27 | Wmf Württembergische Metallwarenfabrik Ag | Metallic cutlery |
DE4124393C2 (en) | 1991-07-23 | 1993-05-27 | Wmf Wuerttembergische Metallwarenfabrik Ag, 7340 Geislingen, De | |
EP0633440A1 (en) * | 1993-07-02 | 1995-01-11 | Abb Research Ltd. | Process for preparing a setter |
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EP0868890A3 (en) * | 1997-04-04 | 2001-11-14 | Injex Corporation | Abutment tooth model and method of manufacturing a prosthetic restoration to be formed thereon |
EP0868890A2 (en) * | 1997-04-04 | 1998-10-07 | Injex Corporation | Abutment tooth model and method of manufacturing a prosthetic restoration to be formed thereon |
DE19925197C2 (en) * | 1998-06-01 | 2001-07-12 | Mold Res Co | Injection moldable metal powder composition and injection molding and sintering processes using such a composition |
WO2005030415A3 (en) * | 2003-09-22 | 2009-04-16 | Mtu Aero Engines Gmbh | Method for the production of components, and holding device |
WO2005030415A2 (en) * | 2003-09-22 | 2005-04-07 | Mtu Aero Engines Gmbh | Method for the production of components, and holding device |
DE102004016333A1 (en) * | 2004-04-02 | 2005-10-27 | Webasto Ag | Heating unit burner with an impact disk made by injection molding located in the combustion chamber in the flame region useful in metallurgical production |
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WO2007005480A1 (en) * | 2005-06-30 | 2007-01-11 | Honeywell International Inc. | Advanced sintering tools for use in metal injection molding of large parts |
US7413702B2 (en) | 2005-06-30 | 2008-08-19 | Honeywell International Inc. | Advanced sintering process and tools for use in metal injection molding of large parts |
US9556072B2 (en) | 2009-06-25 | 2017-01-31 | Basf Se | Process for the continuous thermal removal of binder from a metallic and/or ceramic shaped body produced by injection molding, extrusion or pressing using a thermoplastic molding composition |
WO2015185468A1 (en) * | 2014-06-02 | 2015-12-10 | Basf Se | Process for the production of sintered moldings |
CN106660119A (en) * | 2014-06-02 | 2017-05-10 | 巴斯夫欧洲公司 | Process for production of sintered moldings |
CN106660119B (en) * | 2014-06-02 | 2019-02-05 | 巴斯夫欧洲公司 | The method of production sintering mechanograph |
US10456834B2 (en) | 2014-06-02 | 2019-10-29 | Basf Se | Process for the production of sintered moldings |
DE102015210770A1 (en) * | 2015-06-12 | 2016-12-15 | Rolls-Royce Deutschland Ltd & Co Kg | Component construction, component for a gas turbine and method for producing a component of a gas turbine by metal powder injection molding |
US10619515B2 (en) | 2015-06-12 | 2020-04-14 | Rolls-Royce Deutschland Ltd & Co Kg | Component construction, component for a gas turbine and method for manufacturing a component of gas turbine by metal injection moulding |
CN107398559A (en) * | 2017-08-10 | 2017-11-28 | 攀枝花学院 | A kind of powder injection-molded method of large parts for support of arranging in pairs or groups |
CN111136275A (en) * | 2020-01-20 | 2020-05-12 | 江苏精研科技股份有限公司 | Method for preparing large-area thin-wall part by injection molding |
Also Published As
Publication number | Publication date |
---|---|
US5737683A (en) | 1998-04-07 |
DE59508447D1 (en) | 2000-07-13 |
ES2146686T3 (en) | 2000-08-16 |
JPH0881701A (en) | 1996-03-26 |
EP0701875B1 (en) | 2000-06-07 |
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