United Technologies Corporation

Lester W Jordan

Chester E Yaworsky, Jr

Curtiss G Howard

Joseph F Loersch

Frank L Zampino

John J Brennan

Robert G Adinolfi

Peter Alan Hurwitz

By coating a workpiece with a uniform layer of polyimide containing surfactant upon the nonweld areas, spatter produced in electron beam welding of the workpiece is prevented from adhering to the workpiece surface in the nonweld areas. The polyimide coating is so constituted as to be adherent, heat stable, acid resistant, and chemically removeable. Silicone surfactant is preferred.

Weld spatter protective coating

When drilling very small diameter holes in workpieces, there is a great tendency for expulsed workpiece material to travel back along the electron beam path, and to deposit as debris within the interior of the gun. The debris is caused to mostly land at a recess in the rim of a rotatable interior shield, positioned adjacent the beam path inside the gun. The deflection angle of the electron beam is precisely adjusted so that the expulsed workpiece material lands in the recess, from when it is removed by a scraper. A tab is placed within the recess at the rim of the shield, and helps remove small amounts of deposit which still adhere to stationary parts of the electron beam gun system adjacent to the shield. In this embodiment, a resilient scraper such as a wire brush, is used to remove adhering debris from the rim of the shield.

Electron beam hole drilling apparatus

Disclosed is a method and fixture for applying a thin layer of polymer material to a piece of wavy sheet metal, so that the layer may function as a backer during electron beam drilling. The sheet is drawn to the smooth surface of a fixture using a vacuum, and polymer is flowed across the surface using a curved leveling board, which produces a generally uniform thickness molding. The edges of the backer are molded with a bevel edge by shaped side rails, to provide a relief around the edge of the backer layer. Thus a raised up portion usually occuring at the edge rail will not interfere with the precise spacing which the backer is intended to produce between the sheet and the workpiece holder during electron beam drilling.

Method and apparatus for applying an electron beam drilling backer to a

Backers for electron beam hole drilling contain glass particulates with a binder. For nickel base alloys, the glass particulates have at least 7 weight percent low temperature constituent, with a melting point less than 1500.degree. C., and a balance of high temperature constituent having a vaporization point of greater than 2000.degree. C. at 1 atmosphere. Softening points of the glasses exceed 700.degree. C. and preferably are in the range 800.degree.-1000.degree. C. A useful glass will have a viscosity of at least about 10 Pa.multidot.s when it melts. More preferred silicate glasses contain by weight percent at least 8Al.sub.2 O.sub.3, 9CaO, and 3B.sub.2 O.sub.3.

Backers having glass particulates for electron beam hole drilling

Disclosed is an electron beam hole drilling process in which the workpiece surface where the hole exits is covered with a backer comprising particulate bonded to itself and the exit surface by a binding agent. The backer enables a hole having substantial uniform symmetry along its length to be drilled and is particularly useful for hollow parts and contoured surfaces. Backers removable by liquifying, melting dissolution, leaching and the like, are particularly useful for inaccessible exit surfaces. In a preferred embodiment the backer is comprised of a nonmetallic particulate such as glass while the binder is a soluble silicate.

Backer for electron beam hole drilling

Disclosed is an electron beam drilling process in which the workpiece surface first penetrated by the beam is coated with a stop-off material having the required high temperature resistance for preventing formation of burrs around the perimeter of the hole from hot molten spatter which is ejected from the entrance to the hole during the drilling operation. A preferred stop-off material is a substantially continuous layer of boron nitride on the first penetrated surface of the workpiece.

Method for preventing burr formation during electron beam drilling

This invention involves a method for the hot isostatic compaction of particulate material into an article of intricate configuration. It comprises providing a removable pattern in the appropriate precompaction configuration of the article to be produced, coating the pattern with a first layer of conductive material and a second layer of metallic material, the two layers cooperating to provide a self-supporting and gas-impervious shell around the pattern and removing the pattern from the shell to provide a self-supporting and gas-impervious container having an internal configuration corresponding to the precompaction shape of the article to be produced. The container is then filled with particulate material, evacuated and sealed, and isostatically compacted in a pressure vessel at elevated temperature until the particulate material is compacted into a dense article of complex shape. The container is thereafter removed to obtain the compacted article. Dense articles of complex shape, such as gas turbine engine components including blades, discs and the like, are readily produced by the method of the invention.

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Cranston, RI, United States of America

Lester W Jordan