The range of and particularly the minimum surface roughnesses achievable mainly with cemented carbide but also with single crystal diamond round nosed turning and facing inserts has been experimentally studied, machining aluminium and steel on engineering and precision lathes. Characteristic variations of machined surface profile with feed rate as well as insert edge sharpness and roughness measurements are reported. For aluminium faced by carbide inserts on precision lathes, insert edge radius (re) rather than feed marks determined Rz at low feeds, with Rz ≈0.02re. For steel work material, its properties rather than the insert edge radius became the Rz determining factor.

The range of surface roughnesses, and particularly the minimum roughnesses, achievable mainly with cemented carbide but also with single crystal diamond round nosed turning and facing inserts, has been experimentally studied, machining aluminium on engineering and precision lathes. Insert edge sharpness and roughness measurements and characteristic variations with feed rate of machined surface profile are presented. When machine tool limits are avoided, Rz values down to 0.02 times the insert edge radii have been obtained.

The laser cleaving process is a new method to cut brittle materials such as glass, silicon and ceramics. In this dry process, the material is diced only by the thermal stress induced by the laser irradiation. Therefore, the material is not contaminated with the coolant generally used in the mechanical dicing process, but teh thermal damages are caused on the irradiated surface. The objective of this paper is the prevention of thermal damages in the laser cleaving process of silicon wafer. The cleavin experiments are conducted with pulsed ND:YAG laser and cw Nd:YAG laser. In the cleaving with pulsed laser, the temperature required for crack propagation is investigated by measuring with a two-color pyrometer developed. The critical temperature at which the stress intensity factor slightly exceeds the fracture toughness depends on the pulse frequency, the pulse width, the scanning velocity of laser spot and the material properties. The temperature is also confirmed by the thermal stress analysis. And then, for the cleaving with cd laser, a refrigerating-chuck system is developed to reduce the thermal damage of workpiece. The system refrigerates the working table below the freezing point of water, and the material is fixed on the table by the frozen water between the material and the table. While the silicon oxide is caused on the surface of wafer in the room temperature, the refrigerating-chuch can prevent the thermal damage and improve the linearity of the cleaving trajectory and the reliability of the cleaving process.

The study proposes a non-contact adjustment method of grinding g wheel alignment in ultra-precision grinder by using electric capacitance between a grinding wheel and a reference ball. Cemented carbide with almost no binder is used for die material as molding glass lens. The carbide is one of the most difficult-to-cut materials because of its high hardness. Diamond wheel therefore is generally used for grinding the material under quite light grinding conditions such as less than I micrometer of depth of cut. In such ultra-precision grinding, an alignment and a radius of a grinding wheel must be settled precisely to achieve high efficient grinding. In ultra-precision grinding, grinding and measuring are repeated several times, that is, after grinding the work form is measured, and the result is used to correct a grinding program for next grinding. The method proposed in this study is based on an electric capacitance between grinding wheel having conductivity and the reference ball, this means that the method is carried out without any contact between the wheel and the reference. The capacitance is in inverse proportion to the gap, and that can be measured precisely. Using the method, the alignment and the radius of the wheel can be adjusted within short time.

Turning and drilling tests of the compacts of sintered steel were conducted with various geometries and materials of tools. Reduce of the fracture at the exit of the cutting tool from a work material and surface roughness in machining compact before sintering process were discussed. The tool that has a sharp cutting edge and a large rake angle well cut the grains of compact, and brought good surface finish while the tool wear became large because of chipping. As rake angle decreased, some little hollow resulting from peeling the small pieces of the grain off were observed on machined surface. Subsequently, the flow zone was observed beneath the surface and the roughness became slightly small. When machining with cermet tool that has a chamfer, poor surface was obtained because of the large cutting force and low strength of work material while tool wear became small. The failure at the exit of the tool from work piece in continuous peripheral turning depended on the resultant of feed and thrust. forces. When the force was enough small, the width of failure was about 3 times larger than the grain size. The failure at the exit of the hole in drilling depended on the point angle near the margin. Small point angle near the margin enabled reduction of the size of failure.

High speed milling of nickel based supper alloy INCONEL 718 with (Ti, AI)N coated cemented carbide tool was conducted in the cutting speed range 175 similar to 300 m/min. Cutting temperature was also measured by tool-work thermocouple method. The wear rate depended largely on the temperature. There was the threshold cutting temperature about 600 similar to 700 deg. C. Tool wear rapidly grew at the cutting temperature over the threshold whereas gradually grew below the threshold. Long tool life was obtained under the cutting condition that the cutting temperature was controlled below about 600 deg. C. Increase of feed and axial depth of cut in stead of cutting speed or radial depth of cut was recommended in order to achieve the improvement of metal removal rate and acceptable tool life.

This paper deals with machinability of BN added steels in face milling. When face milling the steels with a carbide tool P 10 or a cermet tool, flank wear of the tool was reduced but maximum crater depth was increased than that in milling S45C. In case of cutting the BN added steels in low oxygen atmosphere with P 10, crater depth was reduced than that in air. When face milling the steel with a TiCN coated carbide tool, flank wear and crater wear rate were reduced compare to machining S45C. It was concluded that the machinability of BN added steels in face milling was influenced by tool materials, Al, B and N content of work materials and cutting atmosphere. Among the tested tools, TiCN coated carbide tool was the most suitable in face milling BN added steels.

In metal cutting, a vertical wall is generally cut by end milling. The wall machined by an end mill, however, has low accuracy owing to the bending of the end mill by cutting forces, especially in the case of a deep wall. Plunge cutting carried out using a shoulder-type milling cutter is widely used for cutting vertical walls because of its high-accuracy. In this study, high-speed plunge cutting, at a cutting speed of over 1000m/min, was carried out on gray cast iron FC250 using cBN inserts, and plain carbon steel S45C was also cut using a TiC-added Al2O3 ceramic tool at a cutting speed of up to 900m/min. The results show that the surface machined by high-speed plunge cutting has greater accuracy than that cut by conventional end milling.

The self-driven rotary cutting tool of which bearing was cooled and lubricated by an oil mist with large amount of air was newly developed and applied to the high speed turning (up to 900 m/min) of 0.45% carbon steel. The effect of the coolant supplied to the bearings was evaluated. Cutting force and cutting temperature were also measured. The results indicated that the cooling by large amount of air was useful for reducing the temperature in bearings, which temperature depended on the axial and the radial load of the bearing. The cutting temperature with the self-driven tool was considerably lower than that of the fixed tool, while the cutting forces of these tools were almost the same. The decrease of the temperature was due to the decrease of the sliding speed of the chip on the self-driven tool.