Yue Xian Song

Drilling Force and Temperature of Bone by Surgical Drill

Drilling force and temperature of tibia at the high speed drilling for improving the design of surgical drills are very important. In this paper we describe experiments using pig tibia bones, measuring the drilling force and temperature of a new design of drill bit and compare the results against a twist drill. The result shows that the drilling force and temperature are affected by the feed rate and drilling speed, which vary with the drilling depth into the bone. The new surgical drill with three top cutting edges can achieve lower temperature below 47oC and lower drilling force than with the stainless steel twist drill and carbide twist drill.

Drilling Force and Chip Morphology in Drilling of PCB Supported Hole

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.

A Review on Drilling Printed Circuit Boards

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.

Experimental Study on Cutting Force of High-Speed Micro-Drilling Flexible Printed Circuit Board

Cutting force is one of the most important parameters in the drilling process of FPC (Flexible printed circuit board). It has a directly affect on the micro-drills’ life and the micro-holes quality. It causes the FPC delamination, pulling of the plastic, the burr of exit hole and other processing defects. In this paper, some experimental investigations of cutting force of high speed micro-drilling are carried out to improve the drilling quality of FPC. The results indicate that the drilling parameters(spindle speed, feed speed and drill-bit diameter) have significant influence on micro-drilling thrust force. The thrust force of drill copper foil is larger than the thrust force of drill adhesiver layer and the thrust force of drill PI layer is the smallest. The larger the thrust force is, the bigger the exit burr is.

The Investigation of Thrust Force of Printed Circuit Board Drilling

This work is focused on the investigation of the influence of the materials of PCB, feed rate, spindle speed and tool wear on thrust force when drilling PCB using 0.3 mm diameter cemented tungsten carbide drills. The results indicate that thrust force increases with feed rate and drill wear, but decreases with spindle speed firstly and then increases with it within the cutting range tested. Thrust force caused by the copper foil is much larger than that caused by the epoxy glass fiber cloth when feed rate is low. However, the difference between them decreases as feed rate increases. The thickness of nail head increases with thrust force. The accuracy of hole location increases with thrust force firstly but decreases afterward. The influence of thrust force on hole wall roughness is not obvious.

Simulation of Drilling on the Copper of PCB with Ultra-High-Speed

This paper gives an introduction of the simulation of ultra-high-speed drilling on the copper of printed circuit board (PCB) by using finite element method (FEM). The cutting force, cutting torque and the distribution of cutting temperature are predicted. The value of cutting force is also be compared with the experimental value. The simulation results show that the experimental value of cutting force agrees well with the FEM value and the value of cutting torque is very small in the drilling process , in addition，the maximum temperature of copper comes up to 209 °C in center area and the temperature of copper chip evacuation from the spiral groove ranges from 135°C to 155 °C.

Module Partition and Application for Printed Circuit Board High Speed Drilling Machine

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.

The Slurry for Glass Polishing by Micro Abrasive Suspension Jets

The influence of different dispersants and suspending agents of CeO2 polishing powder was investigated, including sodium hexametaphosphate, polyethyleneglycoll, polyacrylic acid, anionic polyacrylamide, and their mixtures. The suspension stability of ceria particles in slurries and the pH dependence were examined by the measurement of zeta potential, sedimentation and viscosity, etc. The material removal rate and surface roughness of different slurries for K9 glass polishing were studied. The slurry mixed by three kinds of dispersants can achieved the maximum material removal rate and the minimum surface roughness.

Measurement of Micro-Drill Breakage during PCB Drilling

Due to the weak rigidity of micro-drills and impulse effects, the micro-drill breakage is a common problem in printed circuit board micro-drilling. Traditional micro-drill breakage detection methods and principles, including vacuum-type, laser-type, and contact-type detection, were reviewed in this paper. The comparison of three detection methods showed that the contact-type detection can more satisfy the performance of CNC drilling machine. Three effective contact-detection circuits, including no transformer and rectifier circuit pulse-type, active-type, and trigger-type detection circuit, were introduced. And as a conclusion, differences of these detection methods were compared. Based on the characteristic of three effective micro-drill breakage contact detection circuits, the development trends and designs of innovative detection circuit were proposed to meet the challenges in micro-drill breakage measurement during PCB drilling.

Wavelet Transform Denoise of PCB Drilling Force Signal

In the PCB micro drilling, because the force signal is tiny, and when the micro-drill drill to a certain degree of multilayer PCB, alternate force signals will not appear obvious, through to the drilling force signal analysis, we can know the drill bit position and the materials to the influence of the drill failure, so the drilling force signals denoise seems extremely important. In the processing of the non-stationary signal, traditional signal processing method has a certain extent of insufficient, using the wavelet packet decomposition signal, the white noise variance and amplitude decrease with the increase of wavelet scales, but the signal variance and amplitude has nothing to do with the wavelet transform. According to the view of the signal energy, first of all, we make the multiscale decomposition of the signal, then, by using some of the wavelet packet that has efficient energy to reconstruct the original signal. Comparing with the traditional threshold denoising ,using this method in the test signal to deal with the noise can effectively eliminate the white noise interference, and has good denoising effects besides the simple calculation.