Westinghouse Electric Corporation

Siemens Westinghouse Power Corporation

Jimmy Arthur Cox

William E Kiger

Ian L Wilson

Herman Carter Denny

A method for manufacturing machining tools out of composite powdered metal which is first formed to approximate the desired shape of the machining tool; then bonded metallurgically; and machined to the desired finished shape. Desirably, the forming step employs at least two distinct powdered metals, the first formed to the outer shape over the portion of the tool that interfaces with the work piece and selected to exhibit the desired hardness and wear-resistance properties. The second material supports the hollow form of the first material and includes a shank to interface with the machine that the tool will be employed with. The second material is chosen to exhibit the desired ductility, surface hardness, abrasion resistance and reduced cost. Additional materials can be used for different facets of the tool to obtain an optimum balance of long life, efficient operation and low cost.

Composite material machining tools

A cutting tool for machining a work piece to form a turbine rotor having a longitudinal axis includes a plurality of curved splines extending from a back of the tool to a front of the tool. Each spline is curved so that it is not parallel to a plane perpendicular to the longitudinal axis of the tool. Preferably, each spline is curved in a helical shape in the axial direction. Disposed along each spline are a plurality of cutting teeth. Each tooth has a cutting face that is helical in shape. Due to this helical shape of the cutting face of each tooth, a positive radial rake angle is formed for each tooth and a positive axial rake angle is formed for each tooth. These positive rake angles enhance the characteristics of the cutting process. The top of each tooth is also curved to form radial relief for each tooth. Furthermore, each tooth disposed axially forward of another tooth along a spline has a radial height that is less than the other tooth to provide cutting relief in the axial direction for each tooth.

Helical cutter geometry for a cutting tool used to manufacture turbine

A method and a system for creating an improved cutting tool having a helical shaped cutting surface includes a computer, a computer numerically controlled milling machine and an electric discharge machine. The computer can be programmed to form the female shape of a helical spline of a cutting tool that extends longitudinally from the back of the tool to the front of the tool so that it is not parallel to a plane perpendicular to a longitudinal axis of the tool. Disposed along the spline may be a plurality of cutting teeth that each extend outward from the curved spline and have a cutting face that is curved in both a radial direction and in an axial direction with respect to the cutting tool. After forming the female shape of this spline, the computer can develop a cutting path for a tool of a numerically controlled milling machine and operate the milling machine to create an electrode having the female shape of the spline of the cutting tool. This electrode can be installed into an electric discharge machine that has a cutter blank loaded into the machine. The electric discharge machine can then be employed to form the male shape of the spline of the cutting tool.

Method of and system for manufacturing a helical cutter

A method and apparatus for producing turbine blade roots (23) utilize an electro-discharge machining apparatus (10) to machine critical portions of the blade root (23) and a peening apparatus (25) for peening of the machined portions. The electro-discharge machining of the blade root leaves recast layers (22) on the surface of the blade root (23), and high residual tensile stresses are found in the surface of the blade root (23), which could lead to crack propagation. Peening of the machined surfaces leaves compressive residual stresses near the surface and reduces the recast layers (22). The resulting blade root (23) meets the same specifications for durability and tolerances as a blade root machined using the conventional transfer line type cutting process, but at a fraction of the cost.

Method and apparatus for producing turbine blade roots

A reconditioned tool comprises a cylindrical insert cut from a damaged tool, such as a hog mill, with a milling face formed on one end and a transverse dovetail tenon cut in the other end. The dovetail tenon engages a transverse dovetail mortise in the end face of a cylindrical holder. A transverse slot in the holder splits the end of the holder into two axially extending end sections each of which includes one-half of the dovetail mortise. A clamping device, such as a bolt, draws the two end sections of the holder together to pull the insert firmly against the end faceof the holder through wedging action of the two halves of the dovetail mortise against the dovetail tenon. A locking pin inserted through aligned transverse grooves in the holder and insert prevents a lateral displacement of the insert relative to the holder.

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Clemmons, NC, United States of America

Jimmy Arthur Cox