Preface

Abstract: Hard turning has the advantage of rapidly, elasticity and low energy consuming. It has been a trend to replace the complex grinding processes, especially for small batch machining.The surface roughness value of steel after being grinded will ranged in 0.1 to 1.6 μm Ra. This paper points to the precision hard turning of the hardened mold steel, seeking the cutting conditions that can be received in the surface roughness value below 0.1μm Ra, in order to replace the grinding processes. The precision dry turning test were conducted with ceramic cutting tools. The nose radius of the cutting tool was 1.2 mm and the depth of cut was fixed at 0.05 mm. Through a series of turning test, it can be found that, when cutting speed was at 80 to 200 m / min, and feed rate at 0.005 to 0.009 mm / rev, the surface roughness value would be all below 0.1μm Ra. It was superior to grinding process. So we can say that, it is possible to replace the grinding process by hard turning when machining the hardened mold steel.

Abstract: The influence of whisker orientation on machining mechanism, material removal rate and roughness of finished surface when machining the hydroxyapatite /SiCw composite bioceramics material using ultrasonic machining technology was studied. The research results show that material removal rate and roughness of finished surface increase with the increase of the direction angle θ . Under the same machining condition, the higher is the fracture toughness of the material, the lower the material removal rate is. This provides basis for the ultrasonic machining of hydroxyapatite /SiCw composite bioceramics material.

Abstract: A multi-scale and multi-phase nanocomposite ceramic cutting tool material Al2O3/TiC/TiN(LTN) with high comprehensive mechanical properties has been successfully fabricated by means of adding micro-scale TiC and nano-scale TiN particles. The cutting performance and wear mechanisms of this advanced ceramic cutting tool were researched by turning two kinds of hardened steel 40Cr and T10A respectively. Compared with the commercial ceramic tool LT55, LTN showed a superior wear resistance with certain machining parameters. The machining tests indicated that the new materials tool is suitable for continuously dry cutting of hardened steel with high hardness at high speed.

Abstract: In machining, a complete machining process system consists of the machine tool, the fixture, the tool and the part together, the various errors are also inevitable. The factor analysis approach and the statistical analysis method were put forward to study the machining accuracy on the basis of the error sources analysis of the machining accuracy, and the measures were introduced to improve the machining accuracy by using the factor analysis approach. The change laws are grasped by the analysis of the machining errors, so as to take the appropriate measure to reduce the machining error and improve the machining accuracy.