Papers by Author: Hui Ping Zhang

Abstract: Firstly, with studying three typical aspects as cutting force, cutting temperature and chip breaking behavior, contrast experiments of machinability were made on hydrogenated cylindrical shell materials (2.25Cr-1Mo-0.25V), 45 steel, and stainless steel (1Cr18Ni9Ti). The experiment results show that the depth of cut ap have a larger effect on the main cutting force FZ and the cutting temperature θ than the affection of the feedrate f, for that reason, in order to reduce the main cutting force FZ and the cutting temperature θ, large feedrate situation will be better for machining work of hydrogenated cylindrical shell materials. When cutting hydrogenated cylindrical shell materials , many difficult points appearance, such as large cutting force, high cutting temperature, serious chips winding, chips difficult to break etc, which has worse machinability even than stainless steel(1Cr18Ni9Ti).

Abstract: This paper deals with the effect of cutting speed on chip fracture strain in high speed cutting. Firstly, a chip-fracture-strain-measuring device is designed and made according to chip breaking principle. Secondly, experiments are performed by the chip-fracture-strain-measuring device. The experiment results show that chip fracture strain increases first and then diminishes as cutting speed increasing in high speed cutting while feedrate and depth of cut are constant values. Lastly, the effect of cutting speed on chip fracture strain is theoretically analysed from three main factors which affect chip fracture strain. The study above lays a theory and basis for future investigation of chip fracture strain of the other metals and for future investigation the mechanism and chip breaking forecast system of 3-D groove insert in high speed cutting.

Abstract: Chip control is a major problem to be solved in automated machining system. It involves a total system to produce chips that can be evacuated easily and reliably from the working zone and can be disposed of efficiently. In order to realize those, prediction of chip-breaking in machining is one of effective methods. In this paper, to predict the chip breakage systematically, the equivalent parameters concept is used. Through presenting a study of the effect of complicated groove insert equivalent parameters on chip formation and breaking, a predictive model of chip-breaking is constructed. Finally, chip-breaking experiments are made and the tested results show that differential chip-breaking point’s ratio is fewer than five percent, so it proves that the chip-breaking predictive model is reasonable.

Abstract: This paper deals with chip breaking behaviour of 3-D complex groove inserts in machining carbon constructional steel-45 steel at high cutting speeds .Cutting experiments were performed at eleven different cutting speeds. Firstly, the results showed that by increasing cutting speeds, the changes of the critical feedrate and chip breaking scopes at high cutting speeds machining with 3-D complex groove inserts were nonlinear and not monotonous function relations. Then, mathematic models were built. Secondly, the results showed that the critical depth of cut was a constant value at various cutting speeds. And, the curves of the critical depth of cut were perpendicular lines. For this purpose, the critical depth of cut mathematic model has been built. The study above lays a theory and basis for future investigation of the mechanism of chip breaking with 3-D groove insert in high speed machining.

Abstract: As machining technology develops toward the unmanned and automated system, the need for chip-breaking control is considered increasingly important. In this paper, chip-breaking limit of 3-D complicated groove insert is proposed according to cutting experiments. The mathematical formulation of chip section profile coefficient is established through the analysis of influential effect of 3-D complicated groove on chip section profile. The chip-breaking model is developed to predict the critical feed rate and the critical depth of cut in machining based on analyzing the restricted effect of 3-D complicated groove on chips. Finally, a full experimental validation of the analytical model is presented for chip breaking when the workpiece is steel, 45. The testing results show the critical feed rate model and critical depth of cut model are reasonable and reliable.