Advanced Materials Research Vols. 24-25

Abstract: When machining aerospace monolithic components, most of materials could be removed, resulting in severe deformation of the parts due to the release and redistribution of the blank’s original residual stress, together with the action of cutting loads and clamping force. A finite element model (FEM) is built for predicting the deformation caused by those factors mentioned above. In this model, some key techniques such as material properties, initial residual stress model, and application of dynamic cutting loads and transformation of boundary condition are discussed in details. The proposed model predicts the machining deformation for multi-frame monolithic components. Particular attention is paid to the influence of the bulkhead processing sequence on part deformation. At last the paper puts forwards optimal bulkhead processing sequence based on minimizing the machining deformation.

Abstract: Electrochemical abrasive belt grinding (ECABG) technology, which has the advantage over conventional stone super-finishing, has been applied in bearing raceway super-finishing. However, the finishing effect of ECABG is dominated by many factors, which relationship is so complicated that appears non-linear behavior. Therefore, it is difficult to predict the finishing results and select the processing parameters in ECABG. In this paper, Back-Propagation (BP) neural network is proposed to solve this problem. The non-linear relationship of machining parameters was established based on the experimental data by applying one-hidden layer BP neural networks. The comparison between the calculated results of the BP neural network and experimental results under the corresponding conditions was carried out, and the results indicates that it is feasible to apply BP neural network in determining the processing parameters and forecasting the surface quality effects in ECABG.

Abstract: In Laser Shock Processing when a material is irradiated with short laser pulses (ns)of very high densities(>GW/cm2), a high intensity shock wave is generated. This treatment can reduce the rate of fatigue cracking and stress corrosion cracking in structural metals or alloys needed for aerospace, nuclear power plants, and military applications. And laser shock processing has been shown to be a viable method of strengthen metallic components. Transformation on the characters of aerial engine blade by laser shock processing and influence on the fatigue life with these transformations were studied. And the relatively fatigue life experiment of aerial engine blade was done to validate the influence on the fatigue life of aerial engine by laser shock processing. It was found that laser shock processing could bring residual compressive stress and high-density dislocation on the surface of the blade. All these transformation greatly increase the fatigue life of aerial engine blade.

Abstract: Although research on various diamond polishing techniques has been carried for years, some issues still need to be examined in order to facilitate application on large areas in a cost-efficient manner. A compositive technique for machining efficiently thick diamond films prepared by DC plasma arc jet is reported in the present paper. A two-stage polishing was applied on thick polycrystalline diamond films, by employing first electro-discharge machining (EDM) for rough polishing and subsequently mechanical polishing for finishing operations. Experimental results obtained clearly indicate the applicability of the proposed two-stage technique for fabricating transparent diamond films that can be used for the production of X-ray windows. Appropriate etching with EDM is an effective pretreatment method for enhancing the efficiency of rough polishing process in mechanical polishing of thick diamond film. The machined surfaces of diamond films are studied by Scanning Electron Microscope (SEM) and Raman Scattering Spectroscopy (Raman).

Abstract: This document describes the philosophy on how to produce things. First of all, a sprout of technology in the East and the importance of skill that the technology was born are described. How to fill in the valley between the engineering and technology has been my subject throughout my life. To display original creativity is very important.