EP3693100A1 - Procédé de chapelet de coulée de précision - Google Patents

Procédé de chapelet de coulée de précision Download PDF

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Publication number
EP3693100A1
EP3693100A1 EP20150777.9A EP20150777A EP3693100A1 EP 3693100 A1 EP3693100 A1 EP 3693100A1 EP 20150777 A EP20150777 A EP 20150777A EP 3693100 A1 EP3693100 A1 EP 3693100A1
Authority
EP
European Patent Office
Prior art keywords
chaplet
soluble
die
core
soluble insert
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Withdrawn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
EP20150777.9A
Other languages
German (de)
English (en)
Inventor
Stewart Welch
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.)
Rolls Royce PLC
Original Assignee
Rolls Royce PLC
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 Rolls Royce PLC filed Critical Rolls Royce PLC
Publication of EP3693100A1 publication Critical patent/EP3693100A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/02—Sand moulds or like moulds for shaped castings
    • B22C9/04—Use of lost patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B22C9/108—Installation of cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B22C9/105—Salt cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C21/00—Flasks; Accessories therefor
    • B22C21/12—Accessories
    • B22C21/14—Accessories for reinforcing or securing moulding materials or cores, e.g. gaggers, chaplets, pins, bars
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C7/00—Patterns; Manufacture thereof so far as not provided for in other classes
    • B22C7/02—Lost patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/22—Moulds for peculiarly-shaped castings
    • B22C9/24—Moulds for peculiarly-shaped castings for hollow articles

Definitions

  • the invention relates to a method of supporting a core during lost wax or investment casting.
  • lost wax or investment casting is well known in the production of blades or vanes for use in gas turbine engines.
  • Investment casting is an evolution of the lost-wax casting process in which the desired component is manufactured by injecting wax into the die before dipping it in a ceramic slurry to create an outer shell. The wax is removed and the ceramic shell is then fired to harden. The resulting shell has open cavities for the metal to pour inside in order to produce a product of the desired size and shape.
  • Investment casting is an evolution of this process and is used to create hollow near net-shape metal components. This latter process is adopted as it allows for complex shapes to be reliably manufactured.
  • the process can be further used to create a series of complex internal cooling channels, which are desirable in modern turbine blade and vane design.
  • a ceramic core is manufactured separately usually using a ceramic injection moulding (CIM) technique.
  • CIM ceramic injection moulding
  • a ceramic material usually silica
  • the ceramic core is positioned in the mould before the wax is injected and remains in the ceramic shell during the addition of the molten metal.
  • the internal ceramic core can be subsequently removed at a later processing stage to leave a void where it was positioned.
  • a ceramic core can be manufactured using soluble core manufacturing technology.
  • a soluble insert is premanufactured and placed into a mould before the injection of the ceramic core materials.
  • This soluble insert can subsequently be dissolved and removed. Methods for this process are disclosed in United Kingdom patent GB 2096523 B and United States patent US 4384607 .
  • the use of soluble core manufacturing technology is desirable as it allows for complex re-entrant features to be manufactured.
  • the object of the invention is to overcome or at least minimise one or more of these limitations in the investment casting process.
  • a method of supporting a soluble insert structure within a mould die ceramic injection moulding (CIM) process comprising the steps of: forming a soluble insert structure, forming at least one chaplet that supports the soluble insert structure within the die, the chaplet being formed of a ceramic material that has substantially similar physicochemical properties to the soluble insert structure; and positioning the chaplet to contact the soluble insert structure to the die, the soluble insert being spaced away from an edge of the mould die.
  • CCM mould die ceramic injection moulding
  • the benefit of the present invention is that the chaplet becomes an integral part of the ceramic core. This allows the core and the chaplets to be removed at the same time - in the downstream ceramic core removal process after the investment casting process has been performed; this simplifies the investment casting process.
  • the method may also limit the damage to the soluble insert and subsequent non-conformance of the ceramic core or the compromises that have to be added at the design stage to accommodate the positioning of the soluble insert. Consequently, the method allows for more complex internal structures to be produced, which in turn can lead to components having improved cooling flows within it.
  • the chaplet may comprise a refractory material or a combination of refractory materials.
  • the refractory material may be selected from silica, zirconia, alumina, alumina-silicate and combinations thereof.
  • the chaplet may be adhered to the surface of the soluble insert using glue
  • the chaplet may be adhered to the surface of the soluble insert by contacting the chaplet with the surface of the soluble insert and melting either the surface of the chaplet or of the soluble insert.
  • the chaplet may be adhered to the die surface by contacting the chaplet with the die surface and melting either the surface of the chaplet or the die surface.
  • the chaplet is mounted using location features on the die.
  • the method wherein the resulting soluble core and the chaplet may have a bulk density in the range of around 1.3-2.5 g/cc.
  • the method wherein the resulting soluble core and the chaplet have a core that may have a porosity of around 20-40%.
  • the method wherein the resulting soluble core and the chaplet may be made of silica in the rage of around 30-98% weight.
  • the method wherein the CIM material for the soluble core and the chaplet comprises a binder in a range of around 10-25% weight.
  • the method may be used in the production of vanes, blades or seal segments for gas turbine engines.
  • the chaplet may be removed from the final cast at the same time as the core.
  • the method may further comprise injection moulding an object around the soluble insert structure and the at least one chaplet within the mould die.
  • a gas turbine engine is generally indicated at 10, having a principal and rotational axis 11.
  • the engine 10 comprises, in axial flow series, an air intake 12, a propulsive fan 13, an intermediate pressure compressor 14, a high-pressure compressor 15, combustion equipment 16, a high-pressure turbine 17, an intermediate pressure turbine 18, a low-pressure turbine 19 and an exhaust nozzle 20.
  • a nacelle 21 generally surrounds the engine 10 and defines both the intake 12 and the exhaust nozzle 20.
  • the gas turbine engine 10 works in the conventional manner so that air entering the intake 12 is accelerated by the fan 13 to produce two air flows: a first air flow into the intermediate pressure compressor 14 and a second air flow which passes through a bypass duct 22 to provide propulsive thrust.
  • the intermediate pressure compressor 14 compresses the air flow directed into it before delivering that air to the high pressure compressor 15 where further compression takes place.
  • the compressed air exhausted from the high-pressure compressor 15 is directed into the combustion equipment 16 where it is mixed with fuel and the mixture combusted.
  • the resultant hot combustion products then expand through, and thereby drive the high, intermediate and low-pressure turbines 17, 18, 19 before being exhausted through the nozzle 20 to provide additional propulsive thrust.
  • the high 17, intermediate 18 and low 19 pressure turbines drive respectively the high pressure compressor 15, intermediate pressure compressor 14 and fan 13, each by suitable interconnecting shaft.
  • gas turbine engines to which the present disclosure may be applied may have alternative configurations.
  • such engines may have an alternative number of interconnecting shafts (e.g. two) and/or an alternative number of compressors and/or turbines.
  • the engine may comprise a gearbox provided in the drive train from a turbine to a compressor and/or fan.
  • the ceramic core sections have a greater potential to move and/or break due to the lack of support.
  • the choice and positioning of the chaplets is crucial; thus by having different sizes and shapes of these chaplets allows for these complex structures to be manufactured.
  • soluble core manufacturing technology can be selected and a ceramic core of appropriate shape is formed through injection moulding a ceramic material into a die containing a soluble insert.
  • At least one chaplet for supporting a soluble insert structure within the die is formed of a ceramic material.
  • the chaplets are formed from materials having similar physicochemical properties to that of the core. That is to say that they could have one of or more of similar density or dissolvability, physical or thermal properties.
  • the chaplet and the core may be formed from ceramics comprising silica, zirconia, alumina, alumina-silicates or other refractory materials, and may be bound using a wax or a polymer based binder. Refractory materials are used as they are resistant to decomposition by heat, pressure or chemicals, which is desirable during the casting process.
  • the soluble inserts are placed within the die along with the requisite chaplets at appropriate points to prevent the soluble insert form moving. The positioning of the chaplets relative to the soluble insert needs to take into account the position of the soluble core and the dimensional variation of the soluble core.
  • the soluble core is formed of a using a ceramic injection moulding technique. The soluble core is then then removed from the die.
  • a final inspection step is performed on the soluble core before the core is used for the wax injection process. Prior to the wax injection step an inspection should be carried out to ensure the correct chaplets are used and that they are positioned in the correct positions.
  • Ceramic material is injected into the die and subsequently wax can then be injected into the die around the core.
  • the wax body with the core structure inside is removed from the mould and dipped into a ceramic slurry to create a shell, the wax is then removed, and the shell is fired to hardened with the core and chaplets positioned inside. Molten metal is then poured into the shell to form a blade or other suitable component of the desired size and shape.
  • the shell is broken away leaving the cast blade with the ceramic core manufactured by the soluble core manufacturing process and the chaplets, which have become an integral part of the soluble core. These can, possibly, then be removed by leaching the core material away by dissolving it in an appropriate solvent.
  • the solvent can be for example sodium hydroxide or potassium hydroxide, or any other suitable solvent as would be apparent to the person skilled in the art.
  • the chaplets could be designed and configured to fall out of the casting after completion.
  • the formation of the chaplets themselves aims to meet two main criteria: Firstly, to minimise any surface imperfection formed on the ceramic core; and secondly, to ensure the chaplet retains its position between the soluble insert and the die surface.
  • the chaplet will also leave a witness mark on the ceramic core surface, which needs to be minimised.
  • FIG. 2 shows an example of a non-point contact chaplet 20.
  • the chaplet in this example is formed by injecting moulding a material with similar physicochemical properties to that of the ceramic core.
  • the material is injection moulded into a die or sprue of suitable shape and size in a conventional manner.
  • a recess 22 is added to the chaplet to allow for a greater level of glue to be used.
  • the materials used may include silica, zirconia, alumina, alumina-silicates or other refractory materials. They may also be bound using a wax or a polymer based binder.
  • the chaplets are not limited to this shape but can be any suitable shape from point contacts to more complex shapes.
  • the physicochemical properties can include hardness, density, composition, solubility in differing solvents or any other suitable physicochemical property.
  • the core and chaplet may be made of silica in the rage of around 30-98%.
  • Zircon may be present in the range of around 0-30%.
  • Alumina may be present in the range of around 0-30%.
  • Alumina-silicate may be present in the range of around 0-30%.
  • a binder can be added in the injection formulation in a range of around 10-25%. Furthermore, minor additives may be included in the range of around 0-5%. This may provide a core that has a porosity of around 20-40%. The core may have a bulk density in the range of around 1.3-2.5 g/cc.
  • the examples above are only an example of the materials that could be used, as the person skilled in the art will appreciate that other suitable materials could be used, such as replacing the silica in the blend with alumina. There are three options for securing the chaplet in position, these can be: adhering it to the soluble surface, adhering it to the die surface; or the use of location features.
  • the chaplet can be glued; these can be solvent based, temperature change based, or chemical reaction based adhesives. In this case a thin layer is preferred to minimise the effect on the surface of the part, as the glue will burn out during heat treatment and leave a negative on the surface.
  • the chaplet may be melted and pushed in contact with the surface being adhered to and allowed to cool. Alternatively, another material can be melted between the two and used as an adhesive.
  • the chaplet may be designed to enhance glue adhesion, for example this could be done by creating a recess in the chaplet to allow a greater level of glue to be used, as shown in Figure 2 .
  • the chaplet is for the chaplet to be self-locating on the soluble insert or the within the die by adding location features. This can be done for the use of a single chaplet at a crucial point or for multiple chaplets located around the core structure. An interconnecting passage may be required so that the chaplet does not contact either the surface of the soluble or that of the die. By not using glue there is a reduction in the number of processing steps used.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
EP20150777.9A 2019-02-05 2020-01-08 Procédé de chapelet de coulée de précision Withdrawn EP3693100A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GBGB1901550.2A GB201901550D0 (en) 2019-02-05 2019-02-05 Method of investment casting chaplet

Publications (1)

Publication Number Publication Date
EP3693100A1 true EP3693100A1 (fr) 2020-08-12

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EP20150777.9A Withdrawn EP3693100A1 (fr) 2019-02-05 2020-01-08 Procédé de chapelet de coulée de précision

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US (1) US20200246861A1 (fr)
EP (1) EP3693100A1 (fr)
CN (1) CN111515342A (fr)
GB (1) GB201901550D0 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113441688B (zh) * 2021-06-30 2022-07-08 共享装备股份有限公司 一种芯撑及使用方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3659645A (en) * 1965-08-09 1972-05-02 Trw Inc Means for supporting core in open ended shell mold
US4384607A (en) 1977-07-22 1983-05-24 Rolls-Royce Limited Method of manufacturing a blade or vane for a gas turbine engine
GB2096523B (en) 1981-03-25 1986-04-09 Rolls Royce Method of making a blade aerofoil for a gas turbine
US20120186768A1 (en) * 2009-06-26 2012-07-26 Donald Sun Methods for forming faucets and fixtures
US20130186585A1 (en) * 2006-12-06 2013-07-25 General Electric Company Composite core die, methods of manufacture thereof and articles manufactured therefrom
EP2777841A1 (fr) * 2013-03-13 2014-09-17 Howmet Corporation Noyau de céramique avec insert composite fugitif permettant de couler des surfaces portantes

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN205270753U (zh) * 2015-11-17 2016-06-01 沈阳明禾石英制品有限责任公司 一种具有起定位支撑作用的塑料芯撑的陶瓷型芯
DE102018200705A1 (de) * 2018-01-17 2019-07-18 Flc Flowcastings Gmbh Verfahren zur Herstellung eines keramischen Kerns für das Herstellen eines Gussteils mit Hohlraumstrukturen sowie keramischer Kern

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3659645A (en) * 1965-08-09 1972-05-02 Trw Inc Means for supporting core in open ended shell mold
US4384607A (en) 1977-07-22 1983-05-24 Rolls-Royce Limited Method of manufacturing a blade or vane for a gas turbine engine
GB2096523B (en) 1981-03-25 1986-04-09 Rolls Royce Method of making a blade aerofoil for a gas turbine
US20130186585A1 (en) * 2006-12-06 2013-07-25 General Electric Company Composite core die, methods of manufacture thereof and articles manufactured therefrom
US20120186768A1 (en) * 2009-06-26 2012-07-26 Donald Sun Methods for forming faucets and fixtures
EP2777841A1 (fr) * 2013-03-13 2014-09-17 Howmet Corporation Noyau de céramique avec insert composite fugitif permettant de couler des surfaces portantes

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Publication number Publication date
CN111515342A (zh) 2020-08-11
US20200246861A1 (en) 2020-08-06
GB201901550D0 (en) 2019-03-27

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