Formation and control of burrs in precision machining
The existence of the metal cutting burr not only reduces the dimension and shape accuracy of the workpiece, but also increases the manufacturing cost. Currently, the burr has been the most troublesome obstruction to high productivity and automation of machining processes. In this paper, the hazard of the burrs is systematically discussed in the precision or ultra-precision machining firstly and then, the formation principle and morphology of burrs in precision turning, planing, drilling and milling are studied. Finally many new technologies and methods of restraining or decreasing burrs have been developed by the cutting experiments.
FORMING PRINCIPLE OF TWO SIDE-DIRECTION BURR AND IT'S PREDICTION IN METAL CUTTING
The burr is one of the common phenomena occurring i n metal cutting operations. The mathematical-mechanical model of two side-dir ection burr formation and transformation is established with plane stress-strai n theory,based on the orthogonal cutting. The main laws of formation and change of the burr are revealed,and it is confirmed by experiment result,which first realizes prediction of the forming and changing of the two side-direction burr in metal cutting operation
SR topography of plastically deformed Fe-Si bicrystals - observation in situ and post mortem
SR reflection topography was applied to study the interaction of slip dislocations with the grain boundaries in Fe-4at%Si bicrystals deformed by compression. Three experimental settings with either a white or monochromatic beam were used and the corresponding orientation contrast analysed. Dislocation transmission through the grain boundary was observed in bicrystals with favourable geometry of the slip systems.