Papers by Author: Cheng Yong Wang

Abstract: Taking the machining efficiency and surface quality as the optimization objective, a multi-objective and multi-constrained optimization model of the high-speed milling parameters based on the matching of lengthened shrink-fit holder (LSFH) and cutter was established using fuzzy optimization theory. In this model, the contact performance, grip rigidity and dynamic characteristics of the matching of LSFH and cutter were taken into account. Subsequently, the optimization problem of the fuzzy domain was transformed into the optimization problem of the ordinary domain using the Optimal Level Cut Set Method. The optimization results show that the processing time reduced by 5.95% and 8.54%, the surface roughness decreased by 5.42% and 6.85% compared to conventional optimization model and the parameters recommended by the tool manual respectively. The effectiveness and practicality of this optimization method was further proved by processing examples.

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: A two-dimensional orthogonal thermal-mechanical finite element model by Deform2D finite element analysis software is established in the article. By the adaptive meshing technique, not only cutting process but also the effect on the process of aluminum alloy Al6061-T6 processing as friction coefficient changing is simulated. The simulation shows that the friction coefficient has significant effect on the cutting temperature and cutting force, and the effect is nonlinear. With the increasing of the friction coefficient, the cutting temperature and cutting force will both increase. The impact the friction coefficient has on the surface residual stress is much smaller than the impact on the cutting temperature and cutting force.

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: A printed circuit board or PCB consists of conducting layers typically made of thin copper foil and insulating layers laminated together. Holes through a PCB are typically drilled with tiny drill bits made of solid tungsten carbide. This paper focuses on cutting forces of drilling PCB. The influences of cutting speeds, feed rate and drill diameter on thrust force are investigated. Finally the drilling force experimental formula’s mathematical model is derived.

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: A new grinding method for PCB drill-helical-conical grinding method which is combined helical method and conical method is introduced in this paper. Compared with conical grinding method, helical-conical grinding method avoids the tail rising problem and improves the clearance angle distribution along with the main cutting edge. The mathematical model of this method is given in this paper.

Abstract: Plunge milling is used to remove excessive material rapidly in roughing machining. The cutter feed in the direction of machine spindle which has the highest structural rigidity. Through the single factor experiment of plunge milling a P20 die steel, this paper investigates the influence of side step, forward step, cutting speed, feed per tooth on cutting force. On this basis, the principles of optimization of interpolation milling parameters are proposed. This guidance of mold production practice has significant reference value.

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: High speed milling (HSM) on inclined plane is the basic process of die and mould. The dynamic characteristics of the process are experimentally studied by changing the factors as inclined plane, cutting parameter and feeding mode on the high speed milling machine tool. The angles of inclined plane, spindle speed, feed amount and cutting depth are evaluated by the parameters of cutting forces and vibration. The feeding of projection process limits the milling vibrations mainly from horizontal (X) and (Y) directions. The cutting force reaches the peak value when the angle of inclined plane is 45°. The radial cutting depth shows more effects than the axial cutting depth to cutting force and vibration. However, the axial cutting depth should keep a minimum value when using ball mill.