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.

Characterization of drill bit breakage in PCB drilling process based on high-speed video analysis

Circuit World ◽  
2017 ◽  
Vol 43 (3) ◽  
pp. 89-96 ◽  
Author(s):  
Hongyan Shi ◽  
Xiaoke Lin ◽  
Yun Wang
Keyword(s):  
Video Analysis ◽  
High Speed ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Drilling Process ◽  
Drill Bit ◽  
Content Type ◽  
High Speed Video ◽  
Micro Drill

Purpose The purposes of this paper are to study the characterization of drill bit breakage in printed circuit board (PCB) drilling process based on high-speed video analysis and to provide an important reference for micro drill bit breakage prediction. Design/methodology/approach Based on PCB drilling experiment, the high-speed camera was used to observe the micro drill breakage process and the chip removal process. The variation of chip in the drilling process was studied and one of the key reasons for the drill bit breakage was analysed. Finally, the swing angles’ feature during the breakage process of the micro drill was analysed and researched with the image processing tools of MATLAB. Findings The micro drill was prone to breakage mainly because of the blocked chips. The breakage process of the micro drill can be divided into the stage of stable chips evacuation, the stage of blocked chips and the stage of drill bit breakage. The radians of swing angles were basically in the range of ±0.01 when the drilling possess is normal. But when the radians of swing angles considerably exceeded the range of ±0.01, the micro drill bit may be fractured. Originality/value This paper presented the method to study the characterization of drill bit breakage in the PCB drilling process by using high-speed video analysis technology. Meanwhile, an effective suggestion about monitoring the radians of swing angles to predict the breakage of micro drill bit was also provided.

The influencing mechanism of drilling parameters on micro drilling temperature on the basis of calibration of surface emissivity of micro drill bit

Circuit World ◽  
2016 ◽  
Vol 42 (2) ◽  
pp. 63-68 ◽  
Author(s):  
Hongyan Shi ◽  
Jiali Ning ◽  
Qiuxin Yan
Keyword(s):  
Influencing Factor ◽  
Spindle Speed ◽  
Drill Bit ◽  
Surface Emissivity ◽  
Simple Method ◽  
Content Type ◽  
Drilling Temperature ◽  
Drilling Parameters ◽  
Micro Drilling ◽  
Micro Drill

Purpose The purpose of this paper is to calibrate the surface emissivity of micro drill bit and to investigate the effect of different drilling parameters on the temperature of micro drill bit in printed circuit board (PCB) micro drilling process. Design/methodology/approach The surface emissivity of micro drill bit was obtained by experiments. Analysis of variance (ANOVA) was applied in this study to analysis the effect of different drilling parameters on the temperature of micro drill bit in PCB micro hole drilling. The most significant influencing factor on micro drill bit temperature was achieved by ANOVA. Findings First, the surface emissivity of cemented carbide rod decreased from 0.4 to 0.32 slowly with temperature in the range of 50-220°C. Second, the most significant influencing factor on the micro drill bit temperature was spindle speed among the drilling parameters including spindle speed, retract rate and infeed rate. Research limitations/implications In this paper, the influence of roughness of black coating, carbide rod and micro drill bit on the surface emissivity calibration and the temperature measurement was not considered. Originality/value A new simple method has been presented to calibrate the surface emissivity of micro drill bit. Through calibrating the surface emissivity of micro drill bit, the temperature of micro drill bit can be measured accurately by infrared thermometry. Analyzing the influences of different drilling parameters on the temperature of micro drill bit, the mechanism of drilling parameters on drilling temperature is achieved. The basis for the selection of drilling parameters to improve the hole quality is enhanced.

On‐line temperature measurement of a micro drill bit

Circuit World ◽  
2012 ◽  
Vol 38 (2) ◽  
pp. 55-58 ◽  
Author(s):  
Lianyu Fu ◽  
Qiang Guo
Keyword(s):  
Temperature Measurement ◽  
Drill Bit ◽  
On Line ◽  
Line Temperature ◽  
Micro Drill

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.

Time and Frequency Domain Investigation of the Static and Dynamic Characteristics of Micro-Drilling

Manufacturing ◽  
2003 ◽  
Author(s):  
Anping Guo ◽  
Steve Batzer ◽  
John Roth
Keyword(s):  
Tool Wear ◽  
Dynamic Characteristics ◽  
Time History ◽  
Drilling Process ◽  
Dynamic Features ◽  
Proper Order ◽  
Micro Drilling ◽  
On Line ◽  
Wear Monitoring ◽  
Dynamic Time

In this paper, the dynamic characteristics of micro-drilling process under different cutting conditions and the resulting correlation to tool wear have been studied. Two types of drills, three spindle speeds and two kinds of workpiece materials were used. In-process cutting forces and accelerations were measured. The signals were analyzed in both the time and frequency domains. Some interesting phenomena were observed in the dynamic time-history response during drilling. Progressive functions with the proper order were obtained to describe the curve of the average thrust force with the number of the holes drilled. Dynamic features which were sensitive to tool wear were found. The changing trends of these dynamic features as the drill wear progresses show a feasibility to develop an on-line drill wear monitoring system by evaluating the changes in dynamic features.

Drilling of bone: Effect of drill bit geometries on thermal osteonecrosis risk regions

2018 ◽  
Vol 233 (2) ◽  
pp. 207-218 ◽  
Author(s):  
Mohd Faizal Ali Akhbar ◽  
Ahmad Razlan Yusoff
Keyword(s):  
Ex Vivo ◽  
Helix Angle ◽  
Simulation Software ◽  
Drilling Process ◽  
Drill Bit ◽  
Temperature Elevation ◽  
Bone Drilling ◽  
Drilling Simulation ◽  
Deform 3D ◽  
Bone Effect

Bone-drilling operation necessitates an accurate and efficient surgical drill bit to minimize thermal damage to the bone. This article provides a methodology for predicting the bone temperature elevation during surgical bone drilling and to gain a better understanding on the influences of the point angle, helix angle and web thickness of the drill bit. The proposed approach utilized the normalized Cockroft–Latham damage criterion to predict material cracking in the drilling process. Drilling simulation software DEFORM-3D is used to approximate the bone temperature elevation corresponding to different drill bit geometries. To validate the simulation results, bone temperature elevations were evaluated by comparison with ex vivo bone-drilling process using bovine femurs. The computational results fit well with the ex vivo experiments with respect to different drill geometries. All the investigated drill bit geometries significantly affect bone temperature rise. It is discovered that the thermal osteonecrosis risk regions could be reduced with a point angle of 110° to 140°, a helix angle of 5° to 30° and a web thickness of 5% to 40%. The drilling simulation could accurately estimate the maximum bone temperature elevation for various surgical drill bit point angles, web thickness and helix angles. Looking into the future, this work will lead to the research and redesign of the optimum surgical drill bit to minimize thermal insult during bone-drilling surgeries.

Micro-drilling process control by using adaptive sliding controller

2014 ◽  
Vol 31 (2) ◽  
pp. 201-215
Author(s):  
Hung-Yi Chen
Keyword(s):  
Process Control ◽  
Controller Design ◽  
Sliding Mode ◽  
Learning Ability ◽  
Sliding Mode Controller ◽  
Drilling Process ◽  
Time Varying ◽  
Content Type ◽  
Micro Drilling ◽  
Fuzzy Compensator

Purpose – Recently, the micro-positioning technology has become more important for achieving the requirement of precision machinery. The piezo-actuator plays a very important role in this application area. A model-free adaptive sliding controller with fuzzy compensation is proposed for a piezo-actuated micro-drilling process control in this paper. The paper aims to discuss these issues. Design/methodology/approach – Due to the system's nonlinear and time-varying characteristics, this control strategy employs the functional approximation technique to establish the unknown function for releasing the model-based requirement of the sliding mode control. In addition, a fuzzy scheme with online learning ability is augmented to compensate for the finite approximation error and facilitate the controller design. Findings – The Lyapunov direct method can be applied to find adaptive laws for updating coefficients in the approximating series and tuning parameter in the fuzzy compensator to guarantee the control system stability. With the addition adaptive fuzzy compensator, as less as five Fourier series functions can be used to approximate the nonlinear time-varying function for designing a sliding mode controller for micro-drilling process control. Originality/value – The important advantages of this approach are to achieve the sliding mode controller design without the system dynamic model requirement and release the trial-and-error work of selecting approximation function.

Preparation and performances of coated and aluminous entry boards with water-soluble resins for PCB drilling

Circuit World ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 153-161 ◽  
Author(s):  
Hu Zhou ◽  
Bin Yu ◽  
Ning Li ◽  
Jie Zhou ◽  
Xiaoyang Luo ◽  
...  
Keyword(s):  
Production Efficiency ◽  
Heat Dissipation ◽  
Water Solubility ◽  
Water Soluble ◽  
Circuit Board ◽  
Drilling Process ◽  
Drill Bit ◽  
Scanning Calorimetry ◽  
Location Accuracy ◽  
Content Type

Purpose This paper aims to provide a new drilling entry board for printed circuit board (PCB) process, superior in heat dissipation, lubrication, water solubility and hole location accuracy, achieving an excellent drilling process. Design/methodology/approach Using a mixture of polyethylene glycol (PEG) and water-soluble adhesives as hydrosoluble, endothermic and lubricant resins and aluminum foils as baseplates, a series of coated and aluminous entry boards (CABs) for PCB drilling was successfully prepared. The surface appearance of the entry boards was observed clearly by scanning electron microscopy (SEM). The endothermic and lubricant effects of the resins applied on the CABs was characterized by differential scanning calorimetry (DSC) and their water solubility was tested in the normal-temperature water (25°C). Moreover, the CABs’ good drilling properties were tested when they were used for PCB drilling. Findings The SEM analysis showed that the surfaces of the resin layers coated on the CABs whose coating thicknesses were less than 80 μm were smoother and flatter, which could improve hole location accuracy and reduce drill breakage ratio. By virtue of DSC, the endothermic and lubricant effects of the CABs were proven. The fusion of PEG in the resin layers could absorb the heat produced by drilling, restrain the temperature of the drill bit and hole rising and lubricate the drill bit efficiently when a hole was being drilled, which could achieve high-quality holes with good production efficiency. The water-soluble test showed that the prepared CABs had excellent water solubility at normal temperature, enabling the resin left on the hole walls and in the flute of the drill bit to be washed away easily and thereby improving the drilling efficiency and quality. The drilling tests showed that the increase in the thickness of the CABs’ coating could improve the hole location accuracy and alleviate the bit wear. In addition, the suitable coating thickness could ensure the firm adhering of the resin coating the aluminum foil, effectively avoid drill intertwist and prevent the resin debris from blocking the drilled holes on the surface of the entry board, which could hinder chip removal, resulting in poor hole wall quality and drill breakage. Originality/value This paper has a remarkably high industrial practicality in the PCB manufacture process.

Cutting forces prediction and thermal distribution considering various cutting parameters and wear progression in drilling

2016 ◽  
Vol 7 (6) ◽  
pp. 712-723
Author(s):  
Ioannis Mirisidis
Keyword(s):  
Experimental Data ◽  
Fem Simulation ◽  
Cutting Parameters ◽  
Simulation Software ◽  
Drilling Process ◽  
Three Dimensional Model ◽  
Content Type ◽  
The Real ◽  
Tools Wear ◽  
Chip Geometry

Purpose The purpose of this paper is to develop a finite element method (FEM) supported simulation of drilling process applied to superficially hardened steels and assess the heat treatments effect on the optimum drilling conditions (feed rate, speed, etc.). Design/methodology/approach A three-dimensional model was developed simulating the drilling procedure while experimental data, concerning the chip geometry and force components, were used to validate the model. The developed simulation will allow systematically insight on the tools wear progression induced by the developed temperature and stress fields. Two different cases of simulation were examined. A typical simulation was investigated, which erected with all the standard features found in the FEM simulation software. In the second case, all the experimental data were introduced. Findings The simulation results revealed that the advanced developed FEM model describes sufficiently the real chip geometry. Moreover, the FEM calculations provide an effective tool for predicting occurring temperatures, strain and stresses and thus for approaching the real loads of the cutting tool during drilling. Originality/value This paper fulfills an identified need to study the drilling simulation.

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.

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