A method for machining ribs or grooves on a shaft (7) with an axial bearing (24) forming part of the shaft. The ribs or grooves (32, 24a) are obtained on a workpiece portion of the shaft and of the axial bearing, by moving the shaft or at least one tool holder fitted with a machining tool in a longitudinal direction of machining, by the tool performing reciprocating motions with a position in contact and with a position not in contact with the shaft or the axial bearing from the beginning to the end of the workpiece portion or face. The reciprocating motions are synchronised with the sinusoidal programming carried out in the machining unit, along with the desired and programmed arrangement of the ribs or grooves to be produced.

A method for machining ribs or grooves on a workpiece including a shaft (7) and an air or gas axial bearing (24) attached to the shaft or forming a part of the shaft. The workpiece is rotated about a longitudinal axis of a centrifugal compressor. All of the ribs or grooves are obtained at once by the machining tool on a workpiece portion driven such that it rotates, by moving the workpiece or the tool holder in a longitudinal direction, the machining tool moving back and forth with a machining position in contact with the workpiece and a position wherein it is not in contact with the workpiece from the beginning to the end of the workpiece portion. Reciprocating motions of the machining tool are synchronised with the sinusoidal program, as well as with the desired, programmed arrangement of the ribs or grooves to be produced on the workpiece portion.

A chuck table for holding a plate-shaped workpiece under suction includes a suction plate made of porous ceramics and having a plurality of open pores, and a frame covering a side surface and a reverse side, except an attractive suction surface, of the suction plate and having a plurality of suction grooves defined in an upper surface thereof and a fluid communication passage defined therein that holds the suction grooves in fluid communication with a suction source, the frame supporting the suction plate thereon. The suction plate has a porosity in the range from 60% to 70% by volume, and the open pores have diameters in the range from 10 m to 25 m.

Disclosed herein is a plasma-resistant chamber component and a method for manufacturing the same. A plasma-resistant chamber component of a semiconductor processing chamber that generates a plasma environment includes a ceramic article having multiple polished apertures. A roughness of the multiple polished apertures is less than 32 in.

In one aspect, sintered ceramic bodies are described herein which, in some embodiments, demonstrate improved resistance to wear and enhanced cutting lifetimes. For example, a sintered ceramic body comprises tungsten carbide (WC) in an amount of 40-95 weight percent, alumina in an amount of 5-30 weight percent and ditungsten carbide (W.sub.2C) in an amount of at least 1 weight percent.

In one aspect, sintered ceramic bodies are described herein which, in some embodiments, demonstrate improved resistance to wear and enhanced cutting lifetimes. For example, a sintered ceramic body comprises tungsten carbide (WC) in an amount of 40-95 weight percent, alumina in an amount of 5-30 weight percent and ditungsten carbide (W.sub.2C) in an amount of at least 1 weight percent.

Disclosed herein are systems and methods for polishing internal surfaces of apertures in semiconductor processing chamber components. A method includes providing a ceramic article having at least one aperture, the ceramic article being a component for a semiconductor processing chamber. The method further includes polishing the at least one aperture based on flowing an abrasive media through the at least one aperture of the ceramic article, the abrasive media including a polymer base and a plurality of abrasive particles.

Disclosed herein are systems and methods for polishing internal surfaces of apertures in semiconductor processing chamber components. A method includes providing a ceramic article having at least one aperture, the ceramic article being a component for a semiconductor processing chamber. The method further includes polishing the at least one aperture based on flowing an abrasive media through the at least one aperture of the ceramic article, the abrasive media including a polymer base and a plurality of abrasive particles.

A cutting insert includes a body made of a ceramic material. The body has a first surface, a second surface and at least one flank surface extending between the first surface and the second surface. The first surface includes a chip forming feature extending in a radially outwardly direction to a cutting edge and extending in a radially inwardly direction to an inner edge. The chip forming feature includes a front wall that slopes downward from the cutting edge radially inward toward a rounded bottom surface and a back wall that slopes upward from the rounded bottom surface radially inward to the inner edge. The chip forming feature can include an optional land surface between the cutting edge and the front wall.

A coated cutting tool includes a body and a hard and wear resistant PVD coating on the body, wherein the body is made from a cemented carbide, cermet, ceramics, polycrystalline diamond or polycrystalline cubic boron nitride based materials. Th coating includes a first (Ti,Al)-based nitride sub-coating and a second (Ti,Al)-based nitride sub-coating. The first (Ti,Al)-based nitride sub-coating can be a single layer, and the second (Ti,Al)-based nitride sub-coating can be a laminated structure, wherein the first (Ti,Al)-based nitride sub-coating includes a (Ti.sub.1-xAl.sub.x)N.sub.z-layer where 0.1<x<0.4, 0.6<z<1.2, and wherein the second (Ti,Al)-based nitride sub-coating includes a (Ti.sub.1-x1-y1Al.sub.x1Cr.sub.y1)N.sub.z1 layer where 0.5<x1<0.75, 0.05<y1<0.2, 0.6<z1<1.2.