Papers by Author: Wei Min Zhang

Abstract: The impact caused by clutch engagement or disengagement leads to vehicle jerking problem. To solve the jerking vibration, the model of the power train and the process of the clutch engagement is built up, and the numerical relations between jerking vibration and key factors (such as the stiffness of clutch disc, the stiffness and damper of side shaft and flywheel) are established, the validity of the model is verified by comparing simulation results and results of measurement, finally the key factors influencing the vibration amplitude and frequency are identified by vehicle tests.

Abstract: The motion commands to feed drives constitute a major source for excitation of the vibrations. In this paper the vibration of feed drive caused by the motion commands is simulated by using a mathematic method. The mechanical transmission system is modeled as a dual inertia system. Three typical trajectories are used to analyze the effect of motion profiles on feed drive vibration by using a simulation model of feed drive controller.

Abstract: Resource-efficient production (REP) can be referred to minimum resources input and maximum economic and social benefits output. On the basis of the connotation and characteristics are definitely discussed in detail, this paper describes a general research scheme with pursuing the aim of systematic recycling and production in a closed-loop materials flow. It compasses three levels of planning flexibility: theory, technology and implementation. Additionally, the implement strategy and prospect for REP were also discussed.

Abstract: In order to research dynamic characters of CNC machine tools, the finite element method is always adopted to model the system, and its dynamic characters are analyzed based on the modeling. The large dimension of the model for CNC machine and its key system become a problem to be solved. In this paper, the model reduce methods are compared and analyzed in order to clarify this problem. The transmission system of CNC machine tool is modeled by FEM firstly, then, the model reduction methods of reduce method, subspace method and Block Lanzcos method are applied for its modal analysis. The reduced method have to search a set of master DoF, the subspace is used for calculating partial mode in a relative large scale system with simple geometries;. Block-Lanczos method is adopted when the system with large scale dimension, but it needs good computer storage capacity and performance

Abstract: CNC machine tools has always screw joints in its feed drive systems; In order to obtain good performance of CNC machine tool, it is necessary to model the screw joint with more accuracy and to research its influence on the vibration characters of the feed drive system. In this paper, the screw joint is analyzed by multi-body system theory and is modeled as flexible multi-body; Its mathematical describe of constraint condition is given by the modeling of screw joint. A revise factor is introduced into the process of FEM simulation to reflect the deformation in the screw joint. By this way, the effect of deformation in the screw joint is researched in the modeling under the ANSYS circumstance, the harmonic response under considering deformation contrast to that of without deformation. From the analysis in the simulation, it is necessary to take the deformation of screw joint into account.

Abstract: In order that the CNC machine tool has to achieve very high process accuracy, the bed structure has to have a reasonable construction to meet this strict technical demand. The bed structure of machine tool as a important component is analyzed in order to be clarified about its vibration mechanisms. In this paper, the dynamic character of the bed structure of HTM40100 horizontal mill-turn compound machine center is researched by the finite elements method (FEM) in the circumstance of ANSYS, and modal analysis theory is introduced and applied. Bed structure is modeled as flexible body by FEM. The harmonic response and the modal results is given by calculation and running of the model in ANSYS. The bed structure of machine meets the technical demands well enough after those analyses.

Abstract: Due to raising ability of five-axis CNC machine tools to machine geometrically complex work pieces efficiently and with higher dimensional accuracy, it is necessary to research its mechanical eigenfrequence of mechanical transmission system. Considering the CNC machine tool’s work table runs slowly and has little damp, the system is considered as an invariable system and the whole system is nearly taken as structure in place of mechanism into account; The Finite Element method(FEM) in ANSYS software is presented in this paper to be used for the solution of the modal analysis of screw drive system for CNC machine, an FEM structural model in ANSYS for the system is developed to estimate the modal characteristics effectively and properly here, the results illuminate that vibration forms of the system and the proportional Gain factor in the position control of CNC drive system is estimated.

Abstract: Tool life is an important index to judge machinability of cutting tool. Wear standard is a necessary considered factor to give tool life. Microwave printed board is composite material, wear standard should be found by tool wear experiment under definite machining environment. Life-span data of cutting tools with different combination of cutting parameters is collected through machining experiment. And then based 2 mathematic models: extended Taylor empirical equation and quadratic response surface equation, with regression analysis method, the mathematical models of relationship between cutting parameters and tool life were given respectively. Through comparison of two regression methods, response surface equation based wear equation is given, determining calculating method of tool life for High-speed Machining of Aluminum Base Microwave Printed Circuit Board. Described method can be popularized according to change of machining conditions.

Abstract: Tolerance specification is the activity of specifying tolerances. In current 3D-CAD system, tolerance types and tolerance values are specified by designer manully, and the validity checking of tolerance is no available. To achieve semi-automatic tolerance specification, geometric feature in the next-generation Geometrical Product Specifications and Verification (GPS) was introduced, the corresponding rules between geometric features and tolerance types were presented; The recommended values for tolerance were stored in a database system and constrainted by tolerance principles. Additionally, the implementation of computer aided geometric tolerance specification was proposed. Finally, the initial prototype system was developed to demonstrate the proposed scheme, which aides designer to define reasonable tolerance types and tolerance values in 3D-CAD system.

Abstract: The existing problems of temperature measurement for CNC machine tool are pointed out through analyzing research results of temperature measurement methods, temperature measurement points optimum and temperature variables selection technology. The devices and properties of contact and non-contact temperature measurement are compared and evaluated. The error measurement devices and their technology development of CNC machine tool are described. The measurement methods and results of temperature and error are analyzed by testing on a concrete CNC machine tool. It is concluded that some objective rules exist in various machine tools. The locations of sensitive points for temperature and errors as well as its number can be defined.