Yuan Sheng Zhai

Research on the Fracture and Breakage of Heavy-Duty Turning Tool for Rough Machining Hydrogenated Cylindrical Shell

Analyzing and researching the main failure forms of the hard alloy turning tool in rough machining process of the hydrogenated cylindrical shell’s blank. Then the cutting experiments were done at the site, and the results showed that the main failure forms of the hard alloy turning tool in rough machining process of the blank were tools’ fracture. However the main reason leading into this phenomenon was the mechanical impact of variable frequency and variable load which was caused by the dynamic change of cutting dosage. Integrating the experiment results, and combining the principles of elasticity and the principles of fracture toughness of hard alloy, the measures of protecting the tools from being fractured prematurely in heavy cutting process were worked out, then the research result would provide reference database for practical production.

The Simulation Analysis and Experimental Research on the Process of PCBN Cutting Super-Alloy

Ni-based super-alloy GH4169 that is most widely used in aerospace is one of the most difficult-to-cut materials, which can be machined by Polycrystalline Cubic Boron Nitride (PCBN) tool. In this paper, the cutting process of super-alloy GH4169 with PCBN tool is researched by simulation, combing with the comparison and verification of experiment. The change rules of cutting temperature and force under different cutting parameters are obtained in this study. The reasonable parameter ranges of high efficiency cutting are proposed in cutting parameter optimization, in order to provide a reference for high efficiency machining of super-alloy GH4169 with PCBN tool.

Surface Roughness Prediction Based on Cutting Parameters and Nose Radius in Precision Turning

In precision turning, the quality of surface finish is an important requirement for machined workpiece. Thus, the choice of optimal cutting parameters is very important for controlling the required surface quality. The focus of the present study is to find a correlation between surface roughness and cutting parameters (feed rate, depth of cut) and nose radius in turning 3J33 maraging steel, and to derive mathematical models for the predicted surface roughness based on both of cutting parameters and nose radius. The experimental design is carried out using the quadratic rotary combination design. The regression analysis shows feed rate and nose radius influence surface roughness significantly. With F-ratio test the proposed model is adequate. The method could be useful in predicting roughness parameters as a function of cutting parameters and nose radius.

NC Machining Program Simulation and Experiments for Pelton Runner

With pelton turbines and other complex three-dimensional structure cavities that contains various shaped surfaces and all kinds of larger curvature, the three-axis CNC machine with a tool rotary to achieve the four coordinate overall Pelton CNC machining. According to processing characteristics of pelton runner, the paper determines the selection of materials and the overall structure of the tool. And the appropriate way of milling and milling parameters are made. The overall processing program and processing parameters of pelton runner are designed on this basis. The feasibility of the process and cutting route are verified by the simulation of cutting route and experiments.

Study on Plunge Milling Cutter Design with Finite Element Analysis

Plunge milling cutter withstanding greater loads in heavy milling can cause tool breakage, cutting vibration, even chatter. Firstly, geometric model of plunge milling cutter on various combinations of axial rake angle and radial rake angle are established. Secondly, with combination different axial rake angle and radial rake angle of plunge milling cutter under static load, the amount of deformation plunge milling cutter are calculated by finite element analysis. Finally, the plunge milling cutter first six natural frequencies are given in plunge milling cutter modal analysis with finite element analysis. The results show that minimum total deformation of plunge milling cutter is given with the axial rake angle 5° and radial rake angle-5 ° of the cutter and when the tool working at frequencies up to 10012HZ has caused vibration within the XY plane.

Three-Dimensional Finite Element Analysis in Plunge Milling for Stainless Steel

The three-dimensional finite element modeling and experimental validation of plunge milling of stainless steel (1Cr13) are presented. The commercial software Deform 3D applied for the finite element modeling is studied the effect of feed rate per tooth (fz) on the cutting forces and the temperature fields. The formation of chip in the finite element model is formed by local adaptive remeshing technique. The feed rate per tooth (fz) significantly affects the cutting forces, but slightly influences the maximum temperature of the chip.

Finite Element Simulation on Tool Strength of Rough Turning Cylinder

In this paper, numerical simulation method is used to study the turning tool strength by Deform 3D in the process of rough machining high strength steel (2.25Cr-1Mo-0.25V).It mainly studies the effect of the feed rate on the cutting force. At the same time, non-uniform distribution cutting force got from the simulation results is taken as the numerical simulation mechanical load of turning tool blade strength to study the influence of feed rate on the turning tool strength. The simulation results show that: with the feed increasing, the mechanical load that turning tool blade bears increases. The maximum effective stress and displacement of the turning tool blade is also increased.

Determination of Unit Cutting Force of GH4698 Broaching

Fir tree groove broaching is prone to deformation, which affects the machining precision of rear wheel groove. The numerical broaching force is calculated to improve deformation of the processed round tank .This paper uses the planer to make cutting tests that are carried out in shaping machine to simulate the wheel broaching process and measures the cutting force in the experiment. After analyzing the unit numerical cutting force of GH4698 broaching is finally obtained. It provides a simple method to calculate the cutting force of wheel groove machining.

Three-Dimensional Finite Element Analysis on Heavy Cutting for High Strength Steel

The finite element modeling and experimental validation of three-dimensional heavy cutting of high strength steel (2.25Cr-1Mo-0.25V) are presented. The commercial software Deform 3D applied for the finite element modeling is studied the effect of feed rate on the principal cutting forces and the temperature fields. The friction between the tool and the chip is assumed to follow a shear model and the local adaptive remeshing technique is used for the formation of chip. The feed rate significantly affects the cutting forces, but slightly influences the maximum temperature of the chip. The simulation results are compared with experimental data and found to be in good agreement.

Experimental Research on Damaged Layer of High Strength Alloys in Precision Cutting

In this paper, the effects of cutting parameters and tool geometry parameters on the damaged layer were investigated with precision cutting of high strength alloy experiments. The mechanical and thermal effects on microstructure of sub-surfaces in precision turning high strength alloy are studied with a scanning electron microscope (SEM) analysis. A thin disturbed or plastically deformed layer is distinguished by the presence of grains that are elongated and rotated in the direction of cutting. No significant heat affected layer and phase transformation is found below the machined surface in all the tests. It also implies that mechanical deformation plays a larger role during precision turning.