Papers by Author: Li Xin Huang

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: X-axis and Y-axis workbenches are important parts of PCB drilling machine. Theirs dynamic properties directly affect the overall performance of drilling machine. Modal analysis method was adopted in this paper. Measurement and analysis on vibration of X-axis and Y-axis workbenches based on LMS Test. Lab was carried out. The modal parameters such as natural frequency, damping ratio and corresponding vibration modes were obtained. The results present that the X-axis and Y-axis workbenches have a high fundamental frequency, which is 564Hz and 1014Hz respectively. And the damping ratio is less than 4.91% and 2.99%, which shows that the stiffness of the X-axis and Y-axis workbenches are higher. The FEM modal analysis shows that it has the similar results with the experiments in modal parameters. The analysis of natural characteristics of workbench provides guidance for optimizing machining parameters of drilling and improving structure of workbench.