Papers by Author: Xiao Cun Xu

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: Since almost large die surfaces are free-form surfaces, currently, these are almost manually implemented. In order to overcome this barrier, floating polishing is a feasible polishing technology. The contact friction between polishing disk and workpiece is a key problem of floating polishing technology. This paper tries to study the contact friction between polishing disk and workpiece with ANSYS analysis software. At first, the paper focuses on the contact friction between polishing disk and plane workpiece by ANSYS analysis software, then focuses on the contact friction between polishing disk and cylinder and sphere workpiece with the software. The analysis results show the hypothesis of full friction condition is feasible. The research results will be used for developing the floating polishing.

Abstract: Since almost large die surfaces are free-form surfaces, currently, almost all of large die surfaces are manually polished, causing low working efficiency and stability of die surface quality. In order to overcome this barrier, floating polishing is a feasible polishing technology. In the paper, a new kind of semi-automation polishing device is designed for large dies, by motion simulation and dynamics analysis of the polishing device based on software of Pro/e and ADAMS, the feasibility of function of the polishing mechanism and dynamics character of the key part are studied, the results show that the device has advantages of multi-degree-of-freedom, free location and indifferent equilibrium, the device may reduce die makers’ labor intensity, and short die delivery time.

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: 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.

Abstract: Polishing is usually the last working procedure of making die surface. The roughness of die surface affects using performance of die directly; therefore, surface roughness is a key factor to scale quality of die surface. The paper focuses on affecting factors of polishing surface roughness, including the rotation speed of polishing head, floating force on polishing head, pass of polishing head movement, feeding rate of polishing head, and size of abrasive particles. Then, establish the parameters database in order to select appropriate technological parameters expediently. These results are used as operating guides for applications of die polisher.

Abstract: The polyimide polishing film is a kind of soft polishing films with polyimide substrate and abrasive cement. It isn't replaced by other grinding tool because of its acid resistance, alkali resistance, water-resistance, oil resistance, heat-resistance et al. The paper focuses on ascertaining the minimal substrate thickness of polishing film, selecting molding method and molding technology. Applying the skim coating processes, and using a self-made, film making device, a lab-level, making process of polyimide polishing film is developed, and the polyimide polishing films are made in a lab. Then, study the polishing films form and analyze the molding performances with scanning electron microscope, and get an effect rule of the consistency of polyamides adhesive and abrasive to polyimide polishing films form and the appropriate consistency of polyamides adhesive finally.

Abstract: During the transferring process of the large die surfaces, there are extensive needs of die surface polishing. Since almost large die surfaces are free-form surfaces, currently, these are almost manually implemented. In order to overcome this barrier, base on design a floating polisher, this paper focuses on polishing rule of floating three polishing disks and the optimization of the associated polishing process parameters. In order to enhance the polisher performance, affecting factors of polishing process, including the rotation speed of polishing discs, normal acting force on polishing disc, loci of polishing disc movement, feeding rate of polishing disc, grit of abrasive particles, and inclined angle of the acting force on disc, are synchronized and analyzed versus roughness of polished surfaces. Then, using the parameter design plans and conducts tests regarding these affecting factors. Finally, the floating polishing process parameters are optimized based on the test results. These optimized results are used as operating guides for applications of the floating die polisher.