Wen Jin Wang

Research on Material Removal Algorithm Model in Virtual Milling Process Based on Adaptive Dynamic Quadtrees Algorithm

The realistic dynamic image of virtual milling process is important in the field of virtual manufacturing technology. However, it is difficult to realize virtual 3-D workpiece model removing process. Material removal algorithm model based on an adaptive dynamic quadtrees algorithm is proposed in this paper. Based on mathematical model of virtual material removal, the 3D model of virtual CNC milling process was developed. The real-time simulation of material removal process was realized in the virtual reality environment.

Mathematical Model and Tooth Surface Representation of Face-Gear Drive with Curvilinear-Tooth Cylindrical Gear

A tilted head-cutter is considered the generating tool for the generation of the proposed face-gear and a mathematical model of face-gear with curvilinear shaped teeth is developed according to the differential geometry and meshing theory. The generation of a conjugated pinion is based on application of a tilted head-cutter as well. Computer graphs of the gear with curvilinear shaped teeth are presented based on the developed gear’s mathematical model, and then the equation of the gear-tooth surface is deduced. An example is presented to demonstrate the application of the proposed mathematical model.

Design, Generation and Bending Stress Analysis of Face-Gear with Curvilinear Shaped Teeth

A curvilinear-tooth face-gear has been developed in order to obtain a high contact ratio, reduced bending stresses and lower sliding velocities compared to the spur and helical involute face-gear drives. The generation of the face gear is based on application of a tilted head-cutter whereas the conventional method of generation is based on application of a hob. The tooth surface model of the face-gear is established, and then bending stress analysis is performed by using Finite Element Method. The developed theory is illustrated with numerical examples.

The Confined Chord Error Algorithm for High Precision Machining Parametric Surface

The part’s surface quality of NC machining is influenced by the chord error greatly. The confined chord error algorithm for machining complex parametric surface is proposed for controlling the chord error. The arc length error is utilized to control the chord error of the interpolated point indirectly. The arc length error of interpolated point is computed by trapezia expressions, the coordinate and the first order derivative of interpolated point is computed by the interpolation algorithm. The computed error of confined chord error algorithm is discussed and the simulation indicate that the destined precision of the chord error can be satisfied by this algorithm.

Dynamic Modeling of Predicting Chip Formation Based on Artificial Neural Networks and Real-Time Simulation of Chip

For the problem of process monitoring of chip generation in CNC machining, the dynamic modeling of predicting chip formation using artificial neural networks based on real-time condition intelligent monitoring was studied. The dynamic model of predicting chip formation is established in this paper. Based on mathematical model of chip space motion path, the 3D model of chip shape was developed. The real-time simulation of chip generation was realized in the virtual reality environment.

The Curved Surface Fitting and Optimization of Scattered Points' Data Based on the Given Surface Tolerance and Fairing

The curved surface simple expression which met a given tolerance and fairing can be obtained under the conduction that the surface tolerance and fairing had been predetermined by the fitting optimization of the scattered points of the origin curved surface. The genetic factor and evaluation function are designed for the optimized expression of surface is acquired. The validity of the solution is verified by comparing the computed error between fitting optimization surface and the original surface through the numerical simulation.

Dosimetry and Temperature Evaluation of TEM Chamber for Cell Exposure at 1800 MHz

Using the finite-difference time-domain (FDTD) method, we make a dosimetry study on the specific absorption rate (SAR) in cells exposed to 1800 MHz standing waves produced by the transverse electromagnetic (TEM) chamber. Two types of cultured cells are used, namely, the cell layer and the cell suspension. Based on the calculated SAR distribution, the exposure is characterized by the SAR intensity and homogeneity. We consider different exposure arrangements as the combination of the maximum fields of the standing wave and the polarizations of the Petri dish. The maximum E field and maximum H field are used in turn in the exposure volume, where the Petri dish is polarized in the E, H, k and k directions, respectively. The best exposure arrangements are determined by measuring the intensity and homogeneity of the SAR distribution in cells. For a tight control of the thermal environment, the temperature rise in the cell culture induced by the exposure is calculated by using the finite-difference formulation of the bio-heat conduction equation. The linear relation between the maximum temperature rise and the absorbed power is determined to quantify the exposure power for the temperature control.

SAR and Temperature Evaluations of a 900 Mhz TEM Chamber for Cell Exposure

A dosimetry study is made for experiments on cultured cells exposed to 900 MHz microwave in the transverse electromagnetic (TEM) chamber. The exposure is characterized by the intensity and homogeneity of the specific absorption rate (SAR), as well as the exposure-induced temperature rise. The SAR distribution is calculated by using the finite-difference time-domain (FDTD) algorithm of the Maxwell equations. The finite-difference formulation of the bioheat conduction equation is used to calculate the temperature rise of the in vitro environment. Evaluations of the SAR and temperature are performed systematically for scenarios including two formations of cultured cells, two maximum fields, and four polarizations of the Petri dish holding the cell culture. The exposure is optimized by selecting scenarios with the highest SAR intensity, the best SAR homogeneity, and the effective temperature control.

Computerized Modeling and CNC Machining Simulation of Spiral Bevel Gear

Based on the theory of gearing and differential geometry, a CNC hypoid generator mathematical model for spiral bevel has been developed. A mathematical model of a spiral bevel gear-tooth surface based on the CNC Gleason hypoid gear generator mechanism is proposed in the paper. The simulation of the spiral bevel gear is presented according to the developed machining mathematical model. A numerical example is provided to illustrate the implementation of the developed mathematic models.

Study on the Machining Mathematical Model and Simulation of Face-Gear with Curvilinear Shaped Teeth Based on the Local Conjugate Theory of Gearing

A curvilinear-tooth face-gear has been developed in order to obtain a high contact ratio, reduced bending stresses and lower sliding velocities compared to the spur and helical involute face-gear drives. The machining method for this type of gear was studied based on the differential geometry and meshing theory in this paper. The cutting mathematical model of the face-gear was established, and then the cutting simulation of the face-gear was developed.