Papers by Author: Gang Liu

Abstract: .The research which aimed at low integration and inefficiency of the management in the existing tool management of the machinery manufacturing enterprise (group) in our country, based on the tool whole life cycle theory to develop a tool whole life cycle management system. Tool whole life cycle management not only achieves tool operation management but also achieves tool cost management. The system could use network database to store the data and output the data by the form of sheet. And it achieved tool information inquiry, distribution and integrated management.

Abstract: The research which aimed at low integration and inefficiency of the management in the existing tool management of the machinery manufacturing enterprise (group) in our country, developed tool whole life cycle management system software. It based on the tool whole life cycle theory and adopted Microsoft Visual Basic 6.0 language and Access2003 database. The system could do a series of operation, such as, tool purchasing application, tool adding, tool modifying, tool inquiry, tool borrowing and return, tool breakage forecast. And it could make assembling and disassembling tool sheets according to techniques plan. The system could use network database to store the data and output the data by the form of sheet. And it achieved tool information inquiry, distribution and integrated management.

Abstract: In this research, we computationally analyzed the structural modes of an HSK63E type tool system and verified the results with experimental modal analysis (EMA). The computation was implemented using the finite element method (FEM) based on a linear-elastic theory, with which we computed the natural frequency and obtained the modal shapes under both free and operating conditions. With the method of experimental modal analysis, we also obtained structural modal parameters including the natural frequency, modal shapes and damping ratio under the same free and operating conditions. The computational data were compared with the experimental findings. The reasonable agreement between the two data sets indicated the validity and provided a theoretical basis for using computational methods for determining the natural characteristics and influencing factors of HSK tool system. With this validated FEM model, further analyses were performed to evaluate the unique dynamic performance of the HSK tool system, and to apply dynamic optimum design to other types of HSK tool system.

Abstract: Burr formation is a bottleneck of the production line and deteriorates the automation integrity. To this question, investigations were carried out in this paper on the burr formation in milling aluminum alloy (Al-alloy), in order to enhance productivity and workpiece quality by active process control. Milling burr formation were predicted and minimized for the sake of rough machining and finishing operation, using strategies of tool path planning, processing parameter optimization as well as workpiece rigidity strengthening. The conclusions reached in this paper are useful in practice to realize burr-free Al-alloy milling for manufacturing automation.

Abstract: According to the morphological characteristic of the new rotor steel, the cutting temperature and cutting forces generated by milling were investigated. The cutting temperature and forces resulted in the changes of the microstructure and residual stress of the machined surface. The tensile residual stress in the machined surface was affected more remarkably by the cutting temperature than cutting forces. In the microstructure of the machined surface, the larger plastic deformation in the machined surface and martensitic damage in the subsurface were also observed, which favored the higher tensile residual stress.

Abstract: The engineblock and cylinderhead of automobile are usually made of cast iron, and tapping of blind holes is one of the most demanding operations. As usual, tapping is the final process for an engineblock, and the failure of taps can disable the engineblock possibly. The productivity is restricted because of the low cutting speed and poor wear resistance of high speed steel (HSS) taps. Thereby, according to the demand on high speed cutting and low tact time of modern engine production lines, several new typical special tungsten carbide taps are developed and their cutting performance are evaluated in comparison with the commercial taps. In the process of tapping blind holes in gray cast iron and ductile cast iron, several aspects are studied comparatively such as wear mechanism of the first complete and the last incomplete tooth, tap structure, wear of TiCN coating and effects of coolant on cutting performance of taps. This study indicates that straight coated taps with fewer flutes are suitable for high speed tapping of cast iron.

Abstract: These years, the mold has become a very important forming tool in modern industry. And the die steel is the most important technical and material base in mold industry. To obtain the optimized cutting parameters, this paper introduced the cutting performance of WC-Co carbide cutting tools (P10) from cutting force, the surface roughness, chip deformation and the chip-breaking performance in turning 4Cr13 die steel. And the cutting parameters were optimized by homogeneous design method and multiple linear regression analysis method in this paper. The regression models on cutting forces and surface roughness with the cutting parameters were studied and taken the tests of significance. The result showed that it was more suitable for finish turning 4Cr13 die steel using WC-Co carbide tools at vc =183.3m/min, f=0.2mm/r, ap=0.75mm or vc =200m/min, f=0.1mm/r, ap=1mm.

Abstract: 13%Cr stainless steel has good comprehensive performance, which makes it suitable to work under the condition of high temperature, high pressure and corrosive environment, such as petroleum industry. It can be used as materials of petroleum pipes with buttress thread. Buttress thread turning is a heavy-load machining, which places high requirement on the cutting tool. Based on the cutting characteristics of buttress thread, the machinability of 13%Cr stainless steel is studied by turning experiments. Two kinds of inserts with different geometries were employed in buttress thread turning experiments. Experimental results show that less cutting force, longer tool life, better chip curling effect and surface quality was acquired for the insert with rake angle of 12° , clearance angle of 3° and chip-curling groove during 13%Cr stainless steel buttress thread turning process.

Abstract: Rotor steel 26NiCrMoV145 has been widely employed in aerospace and power industry because of its unique properties. As to this new material that used widely in important places, it is worth studying its machinability. An experiment was carried out to study the cutting forces and tool wear mechanism during high speed dry turning using multilayer Al2O3 coated carbide insert. The orthogonal test was chosen, cutting forces were measured. SEM analysis has been carried out on worn tools to determine the tool wear mechanisms. Crater wear and coating peeling could be found in every cutting speed. Flank face wear appears smooth when cutting speed increases. At last, an optimization of the cutting condition was suggested when considering of material remove rate, cutting forces and tool wear.

Abstract: The α+2βtype Ti-5Al-4.75Mo-4.75V-1Cr-1Fe (TC18) is a very difficult machine material for its low thermal conductivity, low elastic modulus, and high chemical activity. So how to improve the machining efficiency and prolong the tool life have got more and more attentions. In this paper, wear mechanism and wear types of coated (TiN+TiAlN) carbide tool and uncoated carbide tool are presented when face milling the Ti-18 alloy under the same machining condition. The results showed that wear types of PVD coated tool are mainly adhesive, diffusion and crater wear, while the mainly failure mode of uncoated carbide tool is tipping. So it is more appropriate to select the PVD coated tool than uncoated tool in the milling TC18 alloy process.