Papers by Author: Rong Di Han

Abstract: After tool edges sharpen, there are a variety of micro-defects in the area of edge, which will accelerate tool wear and shorten tool life. In order to increase tool life and production efficiency, the area of edge strengthen was needed. In this paper, the electrolysis technology was used to enhance the cutting edge of high-speed steel(HSS) tap, the rounding of the edge region of the forming edge and surface morphology of cutting edge were investigated. And the tapping tests were carried on the Ti6Al4V. The results showed that electrolysis enhanced technology can eliminate the defects, invert a circular edge and improve the tool edge strength. The original tap was worn rapidly in the early stages of wear and the cutting force was changed big variation. The results showed that tap strengthened can reduce tool wear and improve tool life.

Abstract: The machinability of Nickel-based superalloy GH4169 is poor, the traditional methods to machining is application of cutting fluids with the active additives which cause environmental pollution and health problems. In this paper, the water vapor was applied on milling instead of cutting fluids for the aim of green milling GH4169. The effects of water vapor, oil emulsion and dry cutting on milling force and the surface roughness have been examined with carbide tools YG6A. The results of experiments indicated that application of water vapor produced lower milling force, the values were reduced about 7 percent compared to dry cutting, and it is advantage in surface roughness. The research results show that clean production was achieved in metal cutting associated with water vapor cooling and lubricating.

Abstract: Nickel-based alloy Inconel718 is a difficult-to-cut material due to lower thermal conductivity, affinity to react with tool material, the cutting tools wear very rapidly due to the high cutting temperature and high cutting force. It is important to choose tool material reasonably. In this paper, cutting performance of the multi-layer CVD-coated (TiN/Al2O3/TiC) tool and PVD-coated (TiAlN) tool were evaluated by cutting temperature, cutting force, tool wear and tool life. The results showed that PVD-coated (TiAlN) tool was suitable for cutting Inconel718.

Abstract: With Third Wave AdvantEdge FEM software, an equivalent finite element model in tapping has been built, making a simulation study of the chip curling of titanium alloy TC4 and analyzing the influnce of a tap hook angle and chip flute shape on chip curling. Based on the simulation study above, the modified-tooth taps made of high-speed steel W9, which have two types of chip flute shape with a chamfer angle of 7°30´and respectively, were developed and the comparative tests of tapping TC4 have been done. The results indicates that the chip removal effects in hand tapping with the standard flute shape and respectively are on the same level, but the tapping torque has become smaller and more effective to a chamfer angle of .

Abstract: The machinability of nickel-based superalloy GH4169 is very poor, the traditional machining of GH4169 using the cutting fluids with the active additives causes environmental and health problems, which is out of the request of the sustainable development strategy. In this paper a new green cutting technology with overheated water vapor as coolants and lubricants was proposed to achieve the aim of green cutting and high productivity. Cutting experiments and tool wear tests using carbide tool YG6 under dry cutting, emulsion and water vapor were performed. The cutting force, cutting temperature, machined surface quality and tool life were investigated; the curve of flank tool wear and relation between tool life and cutting velocity was carried out. The results of experiments indicated that during water vapor condition, the cutting force and cutting temperature was reduced, the machined surface roughness was improved, and the tool life was longed, respectively, and the higher velocity was taken during the some tool wear condition compared to dry cutting. The research results show that green cutting was achieved associated with overheated water vapor cooling and lubricating, at he same time the machined surface quality and production efficiency was increased.

Abstract: The mechanical model of the tapping torque and the friction one were established based on Theoretical Research of Tapping Forces. A series of standard taps with a cutting cone angle of 7°30′ were prepared from high-speed steel W9 and used to tap Nickel-based superalloy GH4169.It was found that the friction torque was about 45% of the total torque as tapping with the standard taps. Friction torque is the main reason in tapping difficult –to-cut materials.

Abstract: Nickel-based super-alloy belongs to difficult-to-machine materials, its machinability is low. To find out the difficulties of drilling nickel-based super-alloy, it is necessary to study the drilling process. The study on the drilling process of nickel-based super-alloy Inconel 718 is discussed from two aspects, drilling deformation and drilling forces distribution. For studying the drilling deformation characteristics and influence laws, the drilling chip specimens are obtained by using self-made drilling quick-stop device. Then, the empirical formula of shear angle is also given. Finally, the drilling forces distribution is studied. Results shows that: drilling deformation decreases when the distance to chisel edge, drilling speed and feed rate increases; drilling deformation of Inconel 718 is larger than AISI 1045; the ratio of torque and thrust force on the lead cutting edge is 29%~33%, 74%~77%, respectively; the torque and thrust force of Inconel 718 is about 1.8~2.3 times than that of AISI 1045.

Abstract: Knowing the stringent operating conditions to which superalloys are subjected to in automobile, aerospace and gas turbine industries, the machinability of nickel-based superalloy GH4169 is very poor, the traditional cutting fluids in GH4169 machining pollutes environments. The purpose of this study is to clarify the possibility of the turning in high speed (vc＞50m/min)[1]. In particular, the effects of the overheat water vapor with 130°C as cooling lubricant application were examined, through observation and measurement of the shape of the generated chips, machined surface integrity, cutting force and cutting temperature in a series of experiments with dry cutting or overheat water vapor with 130°C as cooling lubricant. As a result of these experiments, it was possible to measure and confirm the effects of the overheat water vapor with 130°C as cooling lubricant in high speed turning.

Abstract: To achieve green machining of titanium alloy Ti-6Al-4V with water steam cooling and lubricating, a 600-800w minitype generator is developed. Compared to dry and water-based emulsion, the using of water steam improves Ti-6Al-4V machinability and prolongs the tool life about 1 time and 0.5 times. And if the same tool life was selected, it would be easy to obtain that as water steam applied the cutting speed can increase about 15% and 10%. As a result, the productivity can be increased. The excellent cooling and lubricating action of water steam could be summarized that water molecule has a small diameter and high speed, can be easily and rapidly to penetrate the capillaries and proceed adsorption in the cutting zone. The results indicate that the using of water steam has the potential to attain the green machining of titanium alloy Ti-6Al-4V.

Abstract: The machinability of Titanium Alloy Ti6Al4V is poor, the traditional methods to machining is application of cutting fluids with the active additives which cause environmental pollution and health problems. In this paper, the dry electrostatic cooling was applied instead of cutting fluid for the aim of green cutting Ti6Al4V. The ionized device and gas supply system was set up, the effects of dry electrostatic cooling, emulsion oil and dry cutting on tool wear have been examined in turning of Ti6Al4V with carbide tools YG8, the curve between tool flank wear and cutting time was proposed, and the equation between cutting speed and tool life was set up. The results of experiments indicated that application of dry electrostatic cooling reduced the tool wear and increased the tool life. The research results show that clean production was achieved in metal cutting associated with dry electrostatic cooling.