Papers by Author: Tong Wang

Abstract: Using cutting speed and the roughness as index, the five factors as pulse duration, peak current, offset, ratio of pulse interval to pulse duration and worktable feed were chosen in dry finishing. Based on the single factor experiment, the central composite design (CCD) method is used to study the effects of the five factors and their interactions on cutting speed and the surface roughness and develop empirical models for cutting speed and roughness Ra. Significant order influencing cutting speed and roughness are found. The results of the verification test show that Ra regression model and cutting speed regression model have high reliability, and can achieve significant prediction effect.

Abstract: This paper aims at getting the finishing process models in HS-WEDM in gas. Using cutting speed and the roughness Ra as index, the five factors of pulse-on time, peak current, offset, pulse interval ratio and worktable feed were chosen in dry finishing. The effects of the five factors and their interaction on cutting speed and the Surface roughness Ra and empirical models for cutting speed and roughness Ra were developed by performing a designed experiment based on the central composite design (CCD) experiments, significant order influencing cutting speed and roughness were found. The results of the verification test show that Ra Regression Model and Cutting Speed Regression Model have high reliability, and can achieve significant prediction effect, more accurate mathematical models are provided for the further HS-WEDM process research.

Abstract: Comparing with conventional WEDM in emulsion, dry finishing of high-speed WEDM (HS-WEDM) has advantages such as higher material removal rate, better surface roughness and straightness. Authors have presented a new procedure as gas-liquid combined multiple cut, in which roughing is processed in dielectric liquid, and semi-finishing is in liquid or gas, while finishing is in gas. For better understanding the effect of machining parameters on surface roughness(Ra) and cutting speed (Vw) in dry finishing, a L25(56) Design test was implemented. The analysis of variance shows that offset and wire length are not significant on Ra and Vw. In this paper, the other four significant parameters, such as pulse duration, pulse interval ratio, peak current and no load worktable feed, were selected as factors in Uniform Design test. The final regression equations for Ra and Vw in terms of the actual parameter values were calculated out with MATLAB. Regression statistics of values R2 imply the two regression equtions fit well with test data and Model F-Values imply the two models are significant. Values t and α for regression equation coefficient tests of Ra and Vw show the major impacting items and interactions between them.

Abstract: Comparing with conventional WEDM in emulsion, dry finishing of high-speed WEDM (HS-WEDM) has advantages such as higher material removal rate, better surface roughness and straightness. Authors have presented a new procedure as gas-liquid combined multiple cut, in which roughing is processed in dielectric liquid, and semi-finishing is in liquid or gas, while finishing is in gas. For better understanding the effect of machining parameters on surface roughness and cutting speed in dry finishing, a L25(56) Design was implemented. The analysis of variance shows that the effect of pulse duration on surface roughness is of high significance, and peak current is of significance respectively, and the effect of no load worktable feed on cutting speed is high significant.

Abstract: This paper investigates a new process of wire electrical discharge machining (WEDM) as gas-liquid combined multiple cut. High-speed WEDM (HS-WEDM) finishing was compared in atmosphere and emulsion. Dry finishing has shorter discharge gap, better straightness and surface roughness and much higher material MRR than that in emulsion. Influences of wire winding speed and no load worktable feed on machined surface quality in dry and wet conditions were discussed. The better straightness obtained in gas is explained by analyzing forces acting on wire electrode. When first cut and second cut were performed both in emulsion liquid, and third cut was done in atmosphere, the surface roughness is improved compared with conventional WEDM.

Abstract: This study investigates the dry WEDM in multiple cut. To improve surface quality with high-speed WEDM (HS-WEDM), a new procedure as Gas-liquid Combined Multiple Cut (roughing is processed in dielectric liquid, and semi-finishing is in liquid or gas, while the finishing is in gas) is presented. Effects of pulse duration, peak current, offset, worktable feed and wire length on roughness and removal rate for dry semi-finishing were studied were studied with L16(45) design, and significant order inflluncing roughness and removal rate were found. Experiment results show that multiple cut with dry WEDM in semi-finishing and finishing can improve surface roughness significantly.

Abstract: To explore machining properties of the EDM in gas basically, thermal fields of single pulse discharge in gas and liquid were analyzed by FEM software ANSYS. Crater size and thermal strain graph affected by instantaneous high temperature owing to single spark were simulated. They can provide references for optimizing parameters of comparative experiments of single pulse EDM in liquid and gas.

Abstract: In order to improve machining quality and productivity of complex curved surfaces in high-speed wire electrical discharge machining (HS-WEDM), an additional numerical control (NC) worktable (rotation-swing-swing worktable) and its NC system were designed. The movement model of the four-axle linkage system was established and simulation was developed using the programming language Visual C++ and standard connection software OpenGL.

Abstract: This study investigates the dry wire electrical discharge machining (WEDM) in multiple cut. To improve surface quality with high-speed WEDM (HS-WEDM), a new procedure as Gas-liquid Combined Multiple Cut (roughing is processed in dielectric liquid, and semi-finishing is in liquid or gas, while the finishing is in gas) is presented. Effects of pulse duration, pulse interval, peak current, offset, wire winding speed and wire length on roughness, straightness and removal rate had been studied in dry and wet conditions. Experiment results show that multiple cut with dry WEDM in semi-finishing and finishing can improve surface roughness significantly.

Abstract: This paper studies the surface quality of mould steel with high-speed wire electrical discharge machining (WEDM) method, which is conducted in gas to improve the accuracy of finish cut, and compares the surface quality in atmosphere and in emulsion dielectric. Experiment results showed that WEDM in atmosphere offers advantages such as better surface roughness and higher material removal rate. The relationship about winding speed and worktable feed on WEDMed surface quality in semi-finishing cut and finishing cut had been obtained. Morover, a new attemption was successful in applying dry WEDM in multiple cut to improve surface roughness.