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The present paper aims to describe the development of a FEM model for the simulation of a die-sinking micro-EDM process. A commercial FEM code specific for the simulation of thermo-mechanical forming processes was used. The developed model was based on the capacity of the code to simulate the removal process or the separation of the material through the mesh element deletion. The electrical discharges were simulated through a proper heat flux and the material melting temperature was set as a trigger for the element deletion. The heat flux was related to the EDM process parameters by means of mathematical models selected from the literature. In the first part of the present work, a model based on a single discharge analysis was developed; then, the model was extended to a sink EDM process characterised by repeated discharges. The model was validated in terms of machining time, top diameter and MRR by the execution of experimental tests. [ABSTRACT FROM AUTHOR]

Reparameterization-based toolpath generation methods are usually adopted for machining triangular meshes, trimmed surfaces and compound surfaces. The quality of the reparameterization has an important effect on that of the surface. In this paper, a combined reparameterization procedure is introduced to generate an optimal mapping between the designed surface and a specified planar circular region with relatively less distortion both in length and in angle. Then, for five-axis sculptured surface machining the mathematical model of spiral guide path with maximum path interval is constructed in the circular region. Cutter contact paths are obtained by inversely mapping the guide path onto the designed surface. Under constraints of gouging and collision, continuous and optimal cutter orientations are subsequently calculated. Finally, the results of simulation and experiment of the machining process are given to illustrate the feasibility and applicability of the proposed method. [ABSTRACT FROM AUTHOR]

This paper proposes a comprehensive quality prediction framework for multistage ma- chining processes, connecting engineering design with the activities of quality modeling, variation propagation modeling and calculation, dimensional variation evaluation, dimensional variation analysis, and quality feedback. Presented is an integrated information model utilizing a hybrid (feature/point-based) dimensional accuracy and variation quality modeling approach that incorporates Monte Carlo simulation, variation propagation, and regression modeling algorithms. Two important variations (kinematic and static) for the workpiece, machine tool, fixture, and machining processes are considered. The objective of the framework is to support the development of a quality prediction and analysis software tool that is efficient in predicting part dimensional quality in a multistage machining system (serial, parallel, or hybrid) from station level to system level. [ABSTRACT FROM AUTHOR]

Digitization modeling and CNC machining method of cone-generated double-enveloping worm drive are proposed in this study. The modeling coordinate frame is developed, and coordinate transformation matrices are also built for different coordinate systems. Next, the common normal vectors and relative velocity vectors of the conical cutter and worm and worm and worm wheel are derived by using differential geometry, kinematic analysis, and coordinate transformation method; then, the mathematical models of the worm drive are established applying spatial meshing principle. In addition, the solving algorithms for the complex multivariate nonlinear constrained mathematical models of the worm drive are developed according to the worm drive’s surface-generating characteristic; then, the meshing point cloud that represents the tooth profile of the worm drive are calculated based on the developed algorithms; finally, the digital CAD models of the worm drive could be constructed on the basis of the point cloud in the modeling software system. The CNC machining code is generated based on the accurate digital CAD models, and the surfaces of the worm drive could be machined in the CNC machining center. The modeling and machining experiment results demonstrate the validity and accuracy of the proposed modeling and CNC machining method for cone-generated double-enveloping worm drive. [ABSTRACT FROM AUTHOR]

This work is motivated by a practical need for operation scheduling for an automobile manufacturing industry involved with machining of different types of vibration dampers. This work aims to minimize the makespan time for relatively different types of vibration dampers with nonuniform flow pattern through a two-parallel inseparable hybrid flow shop. A mathematical model has been developed for simulation of the hybrid flow line performance. The simulation provides data relating to completion time, queue status, and machine utilization of various schedules. After analysis and evaluation of different possible schedules, simultaneous processing of two types of dampers is suggested. The model was evaluated for nonuniform flow pattern for any number of types of dampers for different sets, and a parallel solution based on completion time is suggested. [ABSTRACT FROM AUTHOR]