Advanced Materials Research Vols. 328-330

Abstract: Electropolishing, the anodic dissolution process without contact with tools, is a surface Treatment method to make a surface planarization using an electrochemical reaction with low current density. Stainless steel can be put various applications which require purity and high precision surface of products. The aim of this study is to investigate the characteristic of electropolishing effect for stainless steel workpieces. In order to analyze the characteristics of electropolishing effect, surface roughness and micro-burr size were measured in terms of machining conditions such as current density, machining time and electrode gap. The tendencies about improvement of surface roughness by electropolishing for stainless steel workpieces were determined.

Abstract: For a development and lofting of complex sheet metal parts, the traditional work is hard and lack of accuracy. Using CAD/CAM to aid development and lofting needs neither lofting site nor mathematic models, but can achieve high quality and efficiency. The development and lofting of multi-tapered conical tube with 90º elbows as an example, the paper describes the methods of development and lofting of complex sheet metal parts based on CAD​/CAM technology, such as drawing view of four sections of tapered conical tube with 90º elbow, drawing graphic model and developed view of frustum conical tube, checking the coordination situation of each section oblique cone tube model, and blanking programming using CAXA wire EDM V2 software.

Abstract: Thin-wall components were widely used in aerospace products. However, due to the special shape of the structure and the poor machinability, traditional technologies were hard to mill the thin-wall components, milling vibration influenced in the machining process. In this paper, analytical and experimental identifications of the chatter frequencies in milling processes were presented. In the case of milling, there are several frequency sets arising from the vibration signals, as opposed to the single well-defined chatter frequency of the unstable turning process. Frequency diagrams are constructed analytically and attached to the stability charts of mechanical models of high-speed milling. We proposed the corresponding technological measures to prevent deformation.

Abstract: MS1470 steel is mainly used in the automotive industry, which has high strength, light weight and low cost. However, there always appear grains coarsening, brittle increasing, lower intensity and other issues. To solve this problem, we have analyzed the welding process, the fracture morphology and microstructure etc. The results shown that the microstructure were mainly ferrites and lath martensites. However, grains coarsening in the HAZ were serious, and fracture failure also occurred in the heat affected zone. Meanwhile, MS1470 steel had formed a small amount of pores during rolling process, which also is an important reason for cracks formation.

Abstract: This paper presents FE simulation of Arc welding process using nonlinear transient thermal analysis to study the effect of process parameters on temperature distributions in T-joint fillet welds. An APDL (ANSYS Parametric Design Language) program is developed to define moving surface heat source model with Gaussian distribution into simulations by using commercially available FE code ANSYS. The transient temperature distribution in fillet weld during welding process are predicted and subsequently validated with published experimental results. Influence of heat energy input, electrode angle, welding speed and plate thickness on temperature distribution was further explored. The present work provides a basis for prediction of welding residual stresses and distortions in fillet joints.

Abstract: Researching and analyzing the static characteristic of the hook that functions at the limited load has an important meaning to design larger tonnage hook correctly. Academic analysis structure-strength is implemented on the hook of drillwell DG450. Firstly, based on the characteristic modeling technology, the 3-D entity model of the hook is built used Pro/E. Secondly, the static analysis on three dangerous work condition at ultimate load of the hook is proceeded by FEM software Ansys. The stress and displacement are gained to specify the stress status at the different work condition of the hook. And find out the most dangerous place where the stress is the largest. Important academic elements and data for study and design are provided. The conclusion reference values to design hook and drill safely and prolong the lifetime of drillwell hook.

Abstract: In this paper the characteristics of pulse electrochemical deburring (PECD) is analyzed through a developed mathematical model and main influencing factors such as applied voltage, pulse duty factor, deburring time, initial burr height and initial interelectrode gap on burr height have been analyzed. The paper also highlights the scheme of the developed PECD system designed to operate within the parametric limits. The calculated results obtained from the mathematical model are found to be approximately consistent with the experimental results. The results show that initial burr height h₀=0.057mm is removed, and the fillet radius R=0.248mm is obtained. The present paper through various parametric studies will act as a guideline for the operation of a PECD system.

Abstract: This paper presents an enhanced lift-off process for forming side electrode on the quartz –based double-ended tuning fork (DETF) resonator. In the case of fabricating quartz-based DETF, electrode pattern design is an important issue. Taking advantage of the piezoelectricity effect, a simple surface electrode can excite the flexural motion of the DETF, however it suffers from the large motional resistance. Proposed lift-off process can pattern excitation electrode on the side wall without using special photolithograph equipments. Experimental results demonstrated that the motional resistance can be reduced by several times by forming side electrode using proposed process.

Abstract: The primary program development principles and techniques of detailed drawings and CNC programming based on three-dimensional solid model for light gage steel structure are discussed. Components of the structure with complex spatial relationships and construction details are shown directly, accurately and completely based on 3D solid model, and structure properties and design requirements are integrated into the intelligent model. Therefore, drawings and detailed drawings can be drawn and labeled automatically by projecting and hiding with the extracted geometric information of particular entities. Further more, an automatic programming method for computerized numerical control is proposed, and CNC program are encoded according to manufacture information of parts in the model.

Abstract: Displacement is traditionally deemed to be equivalent to deformation. However, displacement is not exactly deformation, for example, the tip of a workpiece illustrates big displacement, but, it caused by the deformation of main body. In this paper, theory of active and passive deformation is proposed for the evaluation of the deformation of workpiece during heat treatment process and the corresponding algorithm was established. The deformation consists of active and passive deformation; the former is the actual deformation, while the latter is caused by the deformation of other areas. This algorithm was applied to the deformation analysis of a hydraulic turbine blade which is a large thin-walled workpiece. And the real deformation area of the blade is found.