Papers by Author: Ping Ma

Abstract: The aerostatic guide way is one the structure of the air thrust bearings, the carrying capacity and stiffness are important static properties of aerostatic guide way. The restrictor, as the key part of the aerostatic guide way, directly affected the static characteristics. A parametric finite element model of gas film was established with APDL language based on ANSYS in this paper. Then analyzed the restrictor structural effect on the static properties of the aerostatic guide way. It found that orifice diameter and gas chamber diameter have important effect on the static properties of the aerostatic guide way.

Abstract: Abstract．High-speed motorized spindle is a promising technology widely used in high speed machining．The lathe motorized spindle is the key component of the high speed NC lathe and the thermal characteristics of the lathe motorized spindle is one of the major factors influencing the performance of the machine tools．In order to improve the accuracy and reliability of the high speed NC lathe，the thermal characteristic of the high speed NC motorized spindle has been studied in this paper．Firstly，the structure feature of the spindle has been introduced and two major internal heat sources of motorized spindle have been investigated．Secondly，the heat transfer coefficients of the major components of the lathe spindle have been conducted．Then，the 2D temperature field model has been developed with finite element method．Based on it, the temperature field and temperature rises of the spindle have been simulated and the reasonability of temperature distribution of the spindle unit has also been discussed．The research results provide the reference to evaluate of the thermal behavior of the high speed NC motorized spindle．

Abstract: The stiffness of externally pressurized air bearing is nonlinear, so it is difficult for nonlinear modeling and modal analysis with Finite Element Modal Analysis(FEMA). In this paper, the spring-mass system method which use linear springs in place of nonlinear air bearing has been developed to make FEMA of externally pressurized air bearing workbench more easier and faster. The actual modes of the workbench have also been attained with Experimental Modal Analysis (EMA). The results of EMA have a good agreement with FEAM results ,which verifies the feasibility of spring-mass system method.

Abstract: In this paper，the characteristics of GD-II built-in motorized spindle is introduced；the thermal features of the frameless motor and the hybrid bearings have been studied；the 2D temperature field model has also been developed by finite element method．The results of the calculation show that a good efficiency of heat transferring has been achieved with the oil-air lubrication and oil-water heat exchanger．

Abstract: The feed unit is modeled with Solidworks entity, then the combined mechatronic simulation is studied with MATLAB and ADAMS, In this paper，control of information exchange was completed by defining the system input and output variables, it build a mechatronic integrated simulation platform of high speed linear feed system of type GD-3. The acceleration, velocity and displacement curve of linear feed system are simulated and compared with experimental results on optimization of parameters. The results indicate that the mechatronic integrated simulation of virtual prototyping can better analyze and evaluate the velocity and displacement Kinematics characteristics of high-speed linear feed system, the acceleration different between the simulation and experimental is 10.71 percent and the virtual prototyping simulation is verified to be a new approach for analysis of the kinematics characteristics of the high-speed linear feed system.

Abstract: Drilling is a particularly complicated machining process, and it becomes much more complicated when the workpiece is printed circuit boards (PCBs). PCB is composite materials with anisotropy. Even a small defect in PCB may cause great losses. Both the drilling process and PCB structure design have been researched by many scholars. But the investigations into the drilling processes of PCB are not systematic. The present review article address the report about tool materials and geometrics, cutting force, cutting temperature, radial run-out and damages occurring in drilling processes. And as a conclusion, some of these critical issues are proposed to meet the challenges in analysis and optimization for PCB drilling.

Abstract: Supported holes of Printed circuit board (PCB) are drilled with two different drill bits. Drilling force (thrust force and torque) and chip morphology are examined at different cutting parameters, and the effects of the two drills are discussed. The results indicate that the drilling force and chip morphology are affected by the feed rate, spindle speed and drill shape. Thrust force increases with the increasing feed rate, and decreases with the increasing spindle speed. Optimization of drill geometry can reduce the thrust force significantly, and is effective in chip breaking which can improve the chip evacuation during the drilling process.

Abstract: The target of this paper is to design a high speed drilling machine suitable for printed circuit board with micro-hole of 0.1 mm diameter, which has drilling force measuring function and rapid change spindle function. Therefore, in this paper, the main principles of module partition for drilling machine were analyzed. Module partition was conducted for high speed drilling machine of Printed Circuit Board (PCB), as well as using modular components combine PCB high speed drilling machine. Then, performance testing and simulation of dynamic modeling were carried out on the modular PCB high speed drilling machine. The results show that the modular PCB high speed drilling machine has good performance, enough stiffness, better stability and meeting the design requirements. The modular partition laid the foundation for further study on the module creation and reconfiguration of PCB drilling machine.

Abstract: For the design and development of the magneto-rheological (MR) damper in flexible fixture, a mathematical model to describe optimization problem and an optimization procedure are constructed through finite element method. A magnetic structural coupling analysis and a first-order optimization are combined to optimize the structural parameters of MR damper and the damping force of the optimized MR damper is tested on the experimental setup. The results show that the optimized MR damper has a reasonable magnetic flux density distribution and a controllable damping force to meet the requirement of the flexible fixture. The effectiveness and feasibility of the proposed optimization approach are verified.

Abstract: In high speed machining, the feed drives with high velocity and high acceleration are necessary to make full use of the capacities of the high speed motorized spindles. The linear motor feed drive eliminates any mid- transmitting mechanism, which cause achieved the high acceleration. In this paper, the GD-Ⅲ linear induction motor feed drive is introduced, and its controller is modeled and its stiffness has been investigated with simulation program MATLAB & SIMULINK. The influence of the parameters of the controller on the dynamic performance has also been analyzed. The simulation shows that the positional loop proportional gain kv, velocity proportional gain kp, velocity loop integral time constant Tn and the current loop proportional gain kpi have great influence on the dynamics of the linear motor feed drive. In the end, the simulation is verified by the experimental results.