scholarly journals Drilling Vibration in a Micro-Drilling Process Using a Gas Bearing Spindle

2020 ◽  
Vol 12 (10) ◽  
pp. 168781402096900
Author(s):  
Bo-Wun Huang ◽  
Jung-Ge Tseng
Keyword(s):  
Printed Circuit Boards ◽  
Engineering Application ◽  
Drilling Process ◽  
High Rotational Speed ◽  
Spindle System ◽  
Drilling Quality ◽  
Micro Drilling ◽  
Spinning Speed ◽  
Gas Bearing ◽  
Micro Drill

In industry, high-density packaging technology is an unavoidable requirement. Therefore, the drilling hole of printed circuit boards, PCB, requires being much smaller, even down to 0.1 mm or less. Drill fractures are frequently found in the micro drilling process due to the micro scale, hole-location errors, reaming. In all micro drilling failure cases, there existed a large vibration or instability is frequently found because of the insufficient rigidity of supports for a system with a super-high spinning speed. To improve the drilling quality and avoid drill breakage, the effects of support stiffness and high rotational speed of the vibration in the micro drilling process must be studied. Most investigations on the vibration of micro drilling are focused on only drill self-structure. However, in an actual engineering application, the micro drill must be attached in a bearing spindle system. This study considers the vibration of a micro drill with a gas bearing spindle. Hence, it includes the effects of the rotation speed, air pressure, and clearance of gas bearing on the vibration in a micro drilling process. After constructing the governing equations of the system, the numerical analysis by the Fortran programming is performed to solve for the frequency and amplitude response of the spindle system over time. The results indicated that the spindle with the gas bearings effect increased the vibration in the micro-drilling process.

Manufacturing Quality Control Method Based on Bayesian Network Model

2010 ◽  
Vol 450 ◽  
pp. 292-295
Author(s):  
Ye Hong Dong ◽  
Dong Xiang ◽  
Guang Hong Duan
Keyword(s):  
Quality Control ◽  
Bayesian Network ◽  
Model Building ◽  
Control Method ◽  
Drilling Process ◽  
Quality Prediction ◽  
Shewhart Control ◽  
Drilling Quality ◽  
Micro Drilling ◽  
Manufacturing Mode

In order to address the problem of quality control faced in multi-type and small-batch manufacturing mode, the method based on Bayesian Network (BN) is proposed. The building, learning and evolving method as well as the quality prediction and diagnosis method of BN model are described in this paper. The combination of BN model and Shewhart control chart is also mentioned. The model building and evolving method was conducted in PCB micro-drilling process as example, verifying that the prediction accuracy increases with the evolved model. The drilling quality prediction was compared with that obtained through regression analysis and artificial neural network. The advantage of BN model in advanced manufacturing is proved.

Effect of Periodic Drilling Force on Instability in a Drilling Process

2005 ◽  
Vol 219 (8) ◽  
pp. 733-742 ◽  
Author(s):  
B W Huang ◽  
H K Kung ◽  
A W L Yao
Keyword(s):  
Numerical Analysis ◽  
Thrust Force ◽  
Dynamic Instability ◽  
Drilling Process ◽  
Twist Drill ◽  
Unstable Condition ◽  
Drilling Force ◽  
Cutting Geometry ◽  
Drilling Quality ◽  
Spinning Speed

The periodic drilling force effect on the dynamic instability of a drill in a drilling process was investigated. This investigation involves the cutting geometry drilling force from the two active parts of a twist drill subjected to small fluctuations during the drilling process. Theoretically, at some drilling force, this small drilling force fluctuation may lead the system into a dynamically unstable condition. Most hole location errors, reaming, and drill fractures occur in this unstable drilling process phase. The dynamic instability in a drilling process is an important issue in increasing the drilling quality and production rate. In this article, a pretwisted beam with a moving Winkler-type elastic foundation is used to simulate the drill and drilling process. Numerical analysis indicates that the unstable regions are enlarged and shifted to a lower frequency suddenly as the drill bites into a workpiece. It is also observed that the thrust force, spinning speed, and pretwisted angle effects drastically change the dynamic instability of drilling.

Effect of Rapid-Feed Step-Drilling Cycle and Super-High-Speed Spindle for High-Speed Micro Drilling in Printed Wiring Boards

2010 ◽  
Vol 447-448 ◽  
pp. 836-840 ◽  
Author(s):  
Eiichi Aoyama ◽  
Toshiki Hirogaki ◽  
Keiji Ogawa ◽  
Satoshi Nojiri ◽  
Yutaka Takeda
Keyword(s):  
High Speed ◽  
Drilling Process ◽  
Printed Wiring Boards ◽  
Step Method ◽  
Processing Efficiency ◽  
High Productivity ◽  
Micro Holes ◽  
Drilling Quality ◽  
Micro Drilling ◽  
Drilling Conditions

A drilling technique using micro-drills of 0.2 mm or less in diameter and a super-high-speed spindle of 160000 rpm or more has been developed for drilling ultra-micro holes in printed wiring boards (PWBs). The drilling process requires higher reliability and quality to maintain the reliability of the electrical connection between circuit layers. On the other hand, higher processing efficiency is also required in PWBs manufacturing. To maintain high productivity, drilling is normally performed using a non-step method, but heat damage called B-RING occurs around the drilled holes with this method. To solve these problems without the loss of processing efficiency, we applied the rapid-feed step-drilling cycle method. We investigated the B-RING for drilling quality and evaluated the drilling time for processing efficiency under various drilling conditions. We found that using a rapid-feed step-drilling cycle with an appropriate number of steps and feed rates ensures a higher level of hole quality and processing efficiency compared with the conventional non-step drilling.

Temperature simulation and its application in on-line temperature measurement of a micro drill bit

Circuit World ◽  
2015 ◽  
Vol 41 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Hongyan Shi ◽  
Hui Li ◽  
Shengzhi Chen
Keyword(s):  
Temperature Measurement ◽  
Temperature Drop ◽  
Infrared Camera ◽  
Simulation Software ◽  
Drilling Process ◽  
Drill Bit ◽  
Content Type ◽  
Micro Drilling ◽  
On Line ◽  
Micro Drill

Purpose – The purpose of this paper is to obtain the micro drill bit temperature field distribution in micro-drilling process and the temperature drop in retracting process with simulation software. Meanwhile, the key factors that affect the micro drill bit temperature will be obtained as well. The results can also be used to improve the accuracy in on-line drilling temperature measurement. Design/methodology/approach – The purpose of this paper is to obtain the micro drill bit temperature field distribution in micro-drilling process and the temperature drop in retracting process with simulation software. Meanwhile, the key factors that affect the micro drill bit temperature will be obtained as well. The results can also be used to improve the accuracy in on-line drilling temperature measurement. Findings – Micro drill bit high-temperature area mainly concentrates in the cutting edge and chisel edge. With the increase of spindle speed and feed speed, the micro drill bit highest temperature increased. The micro drill bit temperature drop rate reaches 20° in the micro-drilling retraction process with certain parameters. The micro drill bit highest temperature detected by an infrared camera is lower by 22° than that in real drilling. The simulation results can be used to guide the actual industrial production. Originality/value – The simulation results can be applied to revise the temperature measurement by an infrared camera in the drilling process. Drilling experiments show that the simulation method is correct and has certain practical significance. The current temperature measurement method can satisfy most of the requirements of temperature measurements.

Energy Analysis of Micro-drilling Process Used to Manufacture Printed Circuit Boards

2012 ◽  
pp. 305-309 ◽  
Author(s):  
Hae-Sung Yoon ◽  
Binayak Bhandari ◽  
Jong-Seol Moon ◽  
Chung-Soo Kim ◽  
Gyu-Bong Lee ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Energy Analysis ◽  
Drilling Process ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Micro Drilling

Size Effect of Drill Bit on Coupled Vibrations during High Speed Micro-Drilling Process of Composite Printed Circuit Board

2020 ◽  
Vol 975 ◽  
pp. 217-222
Author(s):  
Tien Dat Hoang ◽  
Van Du Nguyen ◽  
Hai Anh Nguyen ◽  
Ngoc Kien Nguyen ◽  
Hoang Thi Hai Yen ◽  
...  
Keyword(s):  
Size Effect ◽  
Dynamic Responses ◽  
Circuit Board ◽  
Drilling Process ◽  
Beam Model ◽  
Drill Bit ◽  
Aspect Ratios ◽  
Micro Drilling ◽  
Micro Drill ◽  
Drill Tool

This paper presents a comprehensive method to consider the size effect of the drill bit on the lateral and torsional vibrations of micro-drill tool accurately. Based on the Euler angles, and Lagrange’s equation, the dynamic micro-drilling spindle model including micro-drilling tool is derived. To express more realistic behaviors of the model, the Timoshenko beam model is employed. The dynamic responses of the micro-drill tool are obtained by utilizing the finite element method and Newmark’s method. The influences of the drill bit with high length to diameter are investigated in three cases as 15:1, 18:1, and 20:1 using the same 0.1 mm diameter drill at a rotational speed of 5×104 rpm during air cutting and cutting of the 6-layer FR-4 composite board. The hole-quality is used to discuss the influences of those drill bit aspect ratios.

Economic parameter design for ultra-fast laser micro-drilling process

2019 ◽  
Vol 57 (20) ◽  
pp. 6292-6314 ◽  
Author(s):  
Jianjun Wang ◽  
Yizhong Ma ◽  
Fugee Tsung ◽  
Gang Chang ◽  
Yiliu Tu
Keyword(s):  
Parameter Design ◽  
Drilling Process ◽  
Economic Parameter ◽  
Micro Drilling

Dynamic characteristics of a drill in the drilling process

2003 ◽  
Vol 217 (2) ◽  
pp. 161-167 ◽  
Author(s):  
B W Huang
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Thrust Force ◽  
Time Dependent ◽  
Drilling Process ◽  
Improve Quality ◽  
Vibration Model ◽  
High Speed Drilling ◽  
Spinning Speed ◽  
Twisted Beam

The dynamic characteristics of high-speed drilling were investigated in this study. To improve quality and produce a higher production rate, the dynamic characteristics of the drilling process need to be studied. A pre-twisted beam is used to simulate the drill. The moving Winkler-type elastic foundation is used to approximate the drilling process. A time-dependent vibration model for drilling is presented. The spinning speed, pre-twisted angle and thrust force effects of the drill are considered. The numerical analysis indicates that the natural frequency is suddenly reduced as the drill moves into a workpiece.

The Downsizing Effects in EDM Drilling of Micro Holes

2013 ◽  
Vol 549 ◽  
pp. 503-510 ◽  
Author(s):  
Gianluca D'Urso ◽  
Giancarlo Maccarini ◽  
C. Merla
Keyword(s):  
Electrical Discharge Machining ◽  
Steel Plates ◽  
Drilling Process ◽  
Micro Edm ◽  
Micro Electrical Discharge Machining ◽  
Micro Holes ◽  
Micro Drilling ◽  
Micro Features ◽  
Electron Microscopes ◽  
Manufacturing Technologies

The recent miniaturization trend in manufacturing, has enhanced the production of new and highly sophisticated systems in various industrial fields. In recent years, machining of the so called difficult to cut materials has become an important issue in several sectors. Micro Electrical Discharge Machining (micro-EDM) thanks to its contactless nature, is one of the most important technologies for the machining of this type of materials and it can be considered as one of the most promising manufacturing technologies for the fabrication of micro components. One of the most relevant applications of micro-EDM is micro-drilling. Micro holes in fact, are widely used for example in micro-electromechanical systems (MEMS), serving as channels or nozzles to connect two micro-features, and in micro-mechanical components. The present study is about micro drilling of metal plates by means of micro-EDM technology. In particular, the aim of this work is to investigate the effects of the downsizing of the micro holes diameter on the drilling performances. The influence of the reduction of the diameters in terms of both process performances (e.g., tool wear, taper rate, diametrical overcut) and general quality of the holes was investigated. Steel plates having thickness equal to 0.8 mm were taken into account. The drilling process was carried out using a micro-EDM machine Sarix SX 200 with carbide electrodes having diameter equal to 300, 200, 100 and 50 μm. Since the standard electrodes adopted in this study had a diameter equal to 300 μm, a wire EDM unit was used to obtain the other electrodes. The relationship between the process parameters considered the most significant and the final output, was studied. Furthermore, the geometrical and dimensional properties of the micro-holes were analyzed using both optical and scanning electron microscopes. In particular, it is demonstrated that the diameter size has a significant influence on the final value of the diametrical overcut while peak current and frequency parameters have a negligible effect.

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