US3672032A - Process for mounting a workpiece for machining - Google Patents

Process for mounting a workpiece for machining Download PDF

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Publication number
US3672032A
US3672032A US882411A US3672032DA US3672032A US 3672032 A US3672032 A US 3672032A US 882411 A US882411 A US 882411A US 3672032D A US3672032D A US 3672032DA US 3672032 A US3672032 A US 3672032A
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United States
Prior art keywords
workpiece
coating
grit
binder
process according
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Expired - Lifetime
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US882411A
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Harry Witherspoon
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Rolls Royce PLC
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Rolls Royce PLC
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Publication date
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q3/00—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine
    • B23Q3/02—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine for mounting on a work-table, tool-slide, or analogous part
    • B23Q3/06—Work-clamping means
    • B23Q3/08—Work-clamping means other than mechanically-actuated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C2215/00—Details of workpieces
    • B23C2215/44—Turbine blades
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/4981—Utilizing transitory attached element or associated separate material
    • Y10T29/49812—Temporary protective coating, impregnation, or cast layer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49998—Work holding

Definitions

  • said coating comprising a grit in a binder and said binder being soluble m a solvent which is non-corrosive to the workpiece material.
  • the present invention relates to the production of a mounting for a workpiece which will facilitate holding the workpiece while machining operations are performed on it.
  • a process for producing a workpiece mounting for holding the workpiece during machining operations comprising the steps of applying a settable coating to a portion of the workpiece, and casting a block of material around said coating when set, said cast-material being solid at room temperature and said coating remaining stable at least up to the melting temperature of said cast material, said coating comprising a grit in a binder and said binder being soluble in a solvent which is noncorrosive to the workpiece material.
  • the encapsulating material is a low melting point alloy e.g., an alloy sold under the trade name of CERROTRUE.
  • the coating may be a mixture of a cement binder, such as methyl cellulose in a solvent, and a suitable grit, a preferred mixture comprises the cement sold under the trade name of NICRO-BRAZE together with sand.
  • the particle size of the grit is preferably in the range between 100 and 220 British Standard mesh and in particular particle sizes of 180 British Standard mesh were found to be most suitable.
  • the mixture is preferably applied to the surface of the workpiece in a viscous form and caused or allowed to harden before application of the encapsulating material.
  • the workpiece is an aerofoil shaped blade for a gas turbine engine and the aerofoil portion is encapsulated in a material so that it can be clamped without damage to the surface of the aerofoil portion while machining operations are performed on the blade.
  • the rotor blade 1 comprises an aerofoil 2 and an un-machined root block 3.
  • the aerofoil 2 has previously been completely machined to its final dimensions and surface finish. Its surface is first degreased and is provided with a coating 4 of cement binder and grit which provides a rough surface for the encapsulating material which is formed into a block 5 surrounding the coating 4.
  • the coating 4 is a mixture of a cement sold under the trade name of NICRO-BRAZE together with grit of a particle size of 180 British Standard mesh.
  • the grit is preferably sand but any hard grit-like material of particle size in the range 100-220 British Standard mesh could be used.
  • the essential property of the grit is that it should provide a keyed surface to the aerofoil to which the encapsulating material can adhere and which will not break up under clamping loads.
  • the coating must be readily removable from the surface of the aerofoil after the machining operation has been completed and the encapsulating alloy matrix removed. In this example the NICRO- BRAZE cement is dissolved off with dichlorethylene.
  • the coating must be sufficiently stable to withstand at least the temperature of the molten encapsulating alloy without detriment to its properties.
  • the coating is applied in this example as a viscous paint and is quick-drying, although other methods of application may be used e.g., dipping into a slurry comprising a mixture of cement and grit.
  • the coating must obviously be sufficiently viscous not to run ofi the aerofoil before drying.
  • the encapsulating material is a low melting point alloy sold under the trade name CERROTRUE" which melts at 180 C.
  • CERROTRUE low melting point alloy sold under the trade name CERROTRUE
  • the above described coating on the surface of the workpiece rovides a k e ed surface for better adhesion of the encaps atrng maten
  • binder has been described with reference to NICRO- BRAZE cement as the binder but it should be understood that alternative forms of binder may be used for example polyvinyl alcohol, cellulose based materials, poly-vinyl butyral, poly-methyl methacrylate.
  • Poly-vinyl alcohol has the advantage that it can be dissolved in water.
  • a process for producing a workpiece mounting for holding the workpiece during machining operations upon the workpiece comprising the sequential steps of a. applying a settable coating, which comprises a grit in a binder, to a portion of the workpiece to provide a key,

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mold Materials And Core Materials (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)

Abstract

A process for producing a removable workpiece mounting for holding the workpiece during machining operations comprising the steps of applying a settable coating to a portion of the workpiece to provide a key, and casting a block of material around said coating when set, said cast material being solid at room temperature and said coating remaining stable at least up to the melting temperature of said cast material, said coating comprising a grit in a binder and said binder being soluble in a solvent which is non-corrosive to the workpiece material.

Description

United States Patent Witherspoon [451 June 27, 1972 4] PROCESS FOR MOUNTING A [56] References Cited WORKPIECE FOR MACHINING UNITED STATES PATENTS [721 Ealmg England 3,191,252 6/1965 Webbere ..l64/75 [73] Assignee: Rolls-Royce Limited 3,541,674 11/1970 Sabel 164/75 2,606,482 8/1952 Sorensen et a1 ..269/7 [22] Filed: Nov. 17, 1969 g 21 A L N 882 411 Primary Examiner-J. Spencer Overholser 1 pp 0 Assistant Examiner-John E. Roethel Attorney-Mawhinney & Mawhinney [30] Foreign Application Priority Data Nov. 15, 1968 Great Britain ..54,188/68 [57] ABSTRACT A process for producing a removable workpiece mounting for [52] 0.8. CI .....29/424, 29/559, 164/75, holding the workpiece during machining operations compris- 164/1 11, 269/7 ing the steps of applying a settable coating to a portion of the [51] Int. Cl ..B23p 17/02 workpiece to provide a key, and casting a block of material [58] Field of Search 164/75, 1 1 1, 91, 98, 100, 101, around said coating when set, said cast material being solid at 164/102, 72; 249/113, 115; 269/7; 51/277; 29/527.6, DIG. 5, DIG. 8, 423, 424, 557, 559
room temperature and said coating remaining stable at least up to the melting temperature of said cast material, said coating comprising a grit in a binder and said binder being soluble m a solvent which is non-corrosive to the workpiece material.
7 Claims, 1 Drawing Figure rIIIII/IIIII.
r a I a r I I v v 4 v r 4 v v a a I d r I I g g I I p I. a I a a i I PROCESS FOR MOUNTING A WORKPIECE FOR MACHINING The present invention relates to the production of a mounting for a workpiece which will facilitate holding the workpiece while machining operations are performed on it.
According to the invention there is provided a process for producing a workpiece mounting for holding the workpiece during machining operations, the process comprising the steps of applying a settable coating to a portion of the workpiece, and casting a block of material around said coating when set, said cast-material being solid at room temperature and said coating remaining stable at least up to the melting temperature of said cast material, said coating comprising a grit in a binder and said binder being soluble in a solvent which is noncorrosive to the workpiece material.
In a preferred form of the invention the encapsulating material is a low melting point alloy e.g., an alloy sold under the trade name of CERROTRUE.
The coating may be a mixture of a cement binder, such as methyl cellulose in a solvent, and a suitable grit, a preferred mixture comprises the cement sold under the trade name of NICRO-BRAZE together with sand.
The particle size of the grit is preferably in the range between 100 and 220 British Standard mesh and in particular particle sizes of 180 British Standard mesh were found to be most suitable.
The mixture is preferably applied to the surface of the workpiece in a viscous form and caused or allowed to harden before application of the encapsulating material.
In a preferred embodiment the workpiece is an aerofoil shaped blade for a gas turbine engine and the aerofoil portion is encapsulated in a material so that it can be clamped without damage to the surface of the aerofoil portion while machining operations are performed on the blade.
An example of the invention will now be described with reference to the accompanying drawing which shows a longitudinal section of a rotor blade with the aerofoil portion coated with a mixture of cement and grit and encapsulated in an alloy matrix.
In the drawing the rotor blade 1 comprises an aerofoil 2 and an un-machined root block 3.
The aerofoil 2 has previously been completely machined to its final dimensions and surface finish. Its surface is first degreased and is provided with a coating 4 of cement binder and grit which provides a rough surface for the encapsulating material which is formed into a block 5 surrounding the coating 4. The coating 4 is a mixture of a cement sold under the trade name of NICRO-BRAZE together with grit of a particle size of 180 British Standard mesh. The grit is preferably sand but any hard grit-like material of particle size in the range 100-220 British Standard mesh could be used. The essential property of the grit is that it should provide a keyed surface to the aerofoil to which the encapsulating material can adhere and which will not break up under clamping loads. The coating must be readily removable from the surface of the aerofoil after the machining operation has been completed and the encapsulating alloy matrix removed. In this example the NICRO- BRAZE cement is dissolved off with dichlorethylene.
Further the coating must be sufficiently stable to withstand at least the temperature of the molten encapsulating alloy without detriment to its properties.
The coating is applied in this example as a viscous paint and is quick-drying, although other methods of application may be used e.g., dipping into a slurry comprising a mixture of cement and grit. The coating must obviously be sufficiently viscous not to run ofi the aerofoil before drying.
The encapsulating material is a low melting point alloy sold under the trade name CERROTRUE" which melts at 180 C. However other encapsulating materials are well known and may be used provided the workpiece is rigidly supported throughout the machining operation.
The above described coating on the surface of the workpiece rovides a k e ed surface for better adhesion of the encaps atrng maten By providing that the coating is readily removable from the surface of the workpiece the machining operation can be performed and both the coating and the encapsulating material removed without physical or chemical damage to the workpiece surface.
The invention has been described with reference to NICRO- BRAZE cement as the binder but it should be understood that alternative forms of binder may be used for example polyvinyl alcohol, cellulose based materials, poly-vinyl butyral, poly-methyl methacrylate. Poly-vinyl alcohol has the advantage that it can be dissolved in water.
We claim:
1. A process for producing a workpiece mounting for holding the workpiece during machining operations upon the workpiece, the process comprising the sequential steps of a. applying a settable coating, which comprises a grit in a binder, to a portion of the workpiece to provide a key,
b. casting a block of material around said coating when set, said cast material being solid at room temperature and said coating remaining stable at least up to the melting temperature of said cast material,
c. holding the workpiece by rigidly clamping the block of material,
d. performing the machining operations upon the workpiece,
e. releasing the workpiece,
f. removing the block of cast material,
g. removing the coating by dissolving the binder in a solvent which is non-corrosive to the workpiece material to yield the workpiece in a finished machined condition.
2. A process according to claim 1 in which the particle size of the grit is in the range between 100 and 200 British Standard mesh.
3. A process according to claim 1 in which the particle size of the grit is 180 British Standard mesh.
4. A process according to claim 1 in which the binder is a methyl cellulose based material in a solvent.
5. A process according to claim 1 in which the binder is poly-vinyl alcohol.
6. A process according to claim 1 in which the grit is aluminium oxide or silicon oxide.
7. A process according to claim 1 in which the workpiece is a gas turbine engine blade having an aerofoil portion to which the settable coating is applied.

Claims (6)

  1. 2. A process according to claim 1 in which the particle size of the grit is in the range between 100 and 200 British Standard mesh.
  2. 3. A process according to claim 1 in which the particle size of the grit is 180 British Standard mesh.
  3. 4. A process according to claim 1 in which the binder is a methyl cellulose based material in a solvent.
  4. 5. A process according to claim 1 in which the binder is poly-vinyl alcohol.
  5. 6. A process according to claim 1 in which the grit is aluminium oxide or silicon oxide.
  6. 7. A process according to claim 1 in which the workpiece is a gas turbine engine blade having an aerofoil portion to which the settable coating is applied.
US882411A 1968-11-15 1969-11-17 Process for mounting a workpiece for machining Expired - Lifetime US3672032A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB54188/68A GB1281532A (en) 1968-11-15 1968-11-15 Improvements in clamping of workpieces for machining

Publications (1)

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US3672032A true US3672032A (en) 1972-06-27

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FR (1) FR2023390A1 (en)
GB (1) GB1281532A (en)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3808668A (en) * 1972-03-09 1974-05-07 Ncr Method of employing a soluble matrix to maintain a plurality of objects in a fixed relationship
US4110885A (en) * 1977-05-26 1978-09-05 Fisher Gauge Limited Encapsulating block and removal apparatus
US4224768A (en) * 1978-12-05 1980-09-30 The United States Of America As Represented By The Secretary Of The Air Force Apparatus for, and method of, plunge grinding
US5105523A (en) * 1991-05-29 1992-04-21 Sheffer Collet Company Method and means assuring repeatable concentricity
US5271487A (en) * 1992-11-27 1993-12-21 Dana Corporation Stabilized driven disk assembly and method of installing a clutch including same
US5639531A (en) * 1987-12-21 1997-06-17 United Technologies Corporation Process for making a hybrid ceramic article
EP1716968A1 (en) * 2005-04-29 2006-11-02 Pratt & Whitney Canada Corp. Method of machining a thin-walled structure using a meltable matrix backing for reinforcing the thin wall structure
US20070163114A1 (en) * 2006-01-13 2007-07-19 General Electric Company Methods for fabricating components
US20080152814A1 (en) * 2006-12-20 2008-06-26 General Electric Company Sprayable water-base platinum-group-containing paint and its applications
US20130149040A1 (en) * 2005-01-03 2013-06-13 American Piledriving Equipment, Inc. Clamp Systems and Methods for Pile Drivers and Extractors
US9249551B1 (en) 2012-11-30 2016-02-02 American Piledriving Equipment, Inc. Concrete sheet pile clamp assemblies and methods and pile driving systems for concrete sheet piles
US9371624B2 (en) 2013-07-05 2016-06-21 American Piledriving Equipment, Inc. Accessory connection systems and methods for use with helical piledriving systems
US10190774B2 (en) 2013-12-23 2019-01-29 General Electric Company Fuel nozzle with flexible support structures
US10288293B2 (en) 2013-11-27 2019-05-14 General Electric Company Fuel nozzle with fluid lock and purge apparatus
US10451282B2 (en) 2013-12-23 2019-10-22 General Electric Company Fuel nozzle structure for air assist injection

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2253801B (en) * 1991-01-10 1994-08-03 Chu Tak Sunh Support for holding work pieces and forming process thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2606482A (en) * 1948-11-04 1952-08-12 O E Sorensen Inc Workholder
US3191252A (en) * 1958-12-29 1965-06-29 Gen Motors Corp Coating protection of metal surfaces during casting
US3541674A (en) * 1966-01-12 1970-11-24 Erik Arne Sabel Method for making an internally reinforced crushing element

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2606482A (en) * 1948-11-04 1952-08-12 O E Sorensen Inc Workholder
US3191252A (en) * 1958-12-29 1965-06-29 Gen Motors Corp Coating protection of metal surfaces during casting
US3541674A (en) * 1966-01-12 1970-11-24 Erik Arne Sabel Method for making an internally reinforced crushing element

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3808668A (en) * 1972-03-09 1974-05-07 Ncr Method of employing a soluble matrix to maintain a plurality of objects in a fixed relationship
US4110885A (en) * 1977-05-26 1978-09-05 Fisher Gauge Limited Encapsulating block and removal apparatus
US4224768A (en) * 1978-12-05 1980-09-30 The United States Of America As Represented By The Secretary Of The Air Force Apparatus for, and method of, plunge grinding
US5639531A (en) * 1987-12-21 1997-06-17 United Technologies Corporation Process for making a hybrid ceramic article
US5105523A (en) * 1991-05-29 1992-04-21 Sheffer Collet Company Method and means assuring repeatable concentricity
US5271487A (en) * 1992-11-27 1993-12-21 Dana Corporation Stabilized driven disk assembly and method of installing a clutch including same
US20130149040A1 (en) * 2005-01-03 2013-06-13 American Piledriving Equipment, Inc. Clamp Systems and Methods for Pile Drivers and Extractors
EP1716968A1 (en) * 2005-04-29 2006-11-02 Pratt & Whitney Canada Corp. Method of machining a thin-walled structure using a meltable matrix backing for reinforcing the thin wall structure
US7454825B2 (en) 2005-04-29 2008-11-25 Pratt & Whitney Canada Corp. Method of manufacturing thin-walled structures
US20070163114A1 (en) * 2006-01-13 2007-07-19 General Electric Company Methods for fabricating components
US20080152814A1 (en) * 2006-12-20 2008-06-26 General Electric Company Sprayable water-base platinum-group-containing paint and its applications
US7749570B2 (en) * 2006-12-20 2010-07-06 General Electric Company Method for depositing a platinum-group-containing layer on a substrate
US9249551B1 (en) 2012-11-30 2016-02-02 American Piledriving Equipment, Inc. Concrete sheet pile clamp assemblies and methods and pile driving systems for concrete sheet piles
US9371624B2 (en) 2013-07-05 2016-06-21 American Piledriving Equipment, Inc. Accessory connection systems and methods for use with helical piledriving systems
US10288293B2 (en) 2013-11-27 2019-05-14 General Electric Company Fuel nozzle with fluid lock and purge apparatus
US10190774B2 (en) 2013-12-23 2019-01-29 General Electric Company Fuel nozzle with flexible support structures
US10451282B2 (en) 2013-12-23 2019-10-22 General Electric Company Fuel nozzle structure for air assist injection
US11300295B2 (en) 2013-12-23 2022-04-12 General Electric Company Fuel nozzle structure for air assist injection
US12055295B2 (en) 2013-12-23 2024-08-06 General Electric Company Fuel nozzle structure for air assist injection

Also Published As

Publication number Publication date
GB1281532A (en) 1972-07-12
FR2023390A1 (en) 1970-08-21
DE1957608A1 (en) 1970-07-23
DE1957608B2 (en) 1976-04-22

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