Optimization of flexible printed circuit board’s cooling with air flow and thermal effects using response surface methodology

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chong Hooi Li ◽  
Mohd Zulkifly Abdullah ◽  
Ishak Abdul Aziz ◽  
Chu Yee Khor ◽  
Mohd Sharizal Abdul Aziz
Keyword(s):  
Nusselt Number ◽  
Response Surface ◽  
Thermal Effects ◽  
Thermal Power ◽  
Operating Conditions ◽  
Circuit Board ◽  
Content Type ◽  
Printed Circuit ◽  
Bga Packages ◽  
Flexible Printed Circuit

Purpose This study aims to investigate the interaction of independent variables [Reynolds number (Re), thermal power and the number of ball grid array (BGA) packages] and the relation of the variables with the responses [Nusselt number ((Nu) ¯ ), deflection/FPCB’s length (d/L) and von Mises stress]. The airflow and thermal effects were considered for optimizing the Re of various numbers of BGA packages with thermal power attached on flexible printed circuit board (FPCB) for optimum cooling performance with least deflection and stress by using the response surface method (RSM). Design/methodology/approach Flow and thermal effects on FPCB with heat source generated in the BGA packages have been examined in the simulation. The interactive relationship between factors (i.e. Re, thermal power and number of BGA packages) and responses (i.e. deflection over FPCB length ratio, stress and average Nusselt number) were analysed using analysis of variance. RSM was used to optimize the Re for the different number of BGA packages attached to the FPCB. Findings It is important to understand the behaviour of FPCB when exposed to both flow and thermal effects simultaneously under the operating conditions. Maximum d/L and von Misses stress were significantly affected by all parametric factors whilst (Nu)¯ is significantly affected by Re and thermal power. Optimized Re for 1–3 BGA packages with maximum thermal power applied has been identified as 21,364, 23,858 and 29,367, respectively. Practical implications This analysis offers a better interpretation of the parameter control in FPCB with optimized Re for the use of force convection electronic cooling. Optimal Re could be used as a reference in the thermal management aspect in designing the BGA package. Originality/value This research presents the parameters’ effects on the reliability and heat transfer in FPCB design. It also presents a method to optimize Re for the different number of BGA packages attached to increase the reliability in FPCB’s design.

Heat transfer and deformation analysis of flexible printed circuit board under thermal and flow effects

Circuit World ◽  
2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chong Hooi Lim ◽  
M.Z. Abdullah ◽  
I. Abdul Azid ◽  
C.Y. Khor ◽  
M.S. Abdul Aziz ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Printed Circuit Board ◽  
High Reliability ◽  
Circuit Board ◽  
Deformation Analysis ◽  
Content Type ◽  
Printed Circuit ◽  
Bga Packages ◽  
Flexible Printed Circuit ◽  
Flow Effects

Purpose The purpose of this study is to investigate heat transfer and deformation of flexible printed circuit board (FPCB) under thermal and flow effects by using fluid structure interaction. This study simulate the electronic cooling process when electronic devices are generating heat during operation at FPCB under force convection. Design/methodology/approach The thermal and flow effects on FPCB with attached ball grid array (BGA) packages have been investigated in the simulation. Effects of Reynolds number (Re), number of BGA packages attached, power supplied to the BGA packages and size of FPCB were studied. The responses in the present study are the deflection/length of FPCB (δ/L) and Nusselt number (Nu). Findings It is important to consider both thermal and flow effects at the same time for understanding the characteristic of FPCB attached with BGA under operating condition. Empirical correlation equations of Re, Prandtl number (Pr), δ/L and Nu have been established, in which the highest effect is of Re, followed by Pr and δ/L. The δ/L and Nu¯ were found to be significantly affected by most of the parametric factors. Practical implications This study provides a better understanding of the process control in FPCB assembly. Originality/value This study provides fundamental guidelines and references for the thermal coupling modelling to address reliability issues in FPCB design. It also increases the understanding of FPCB and BGA joint issues to achieve high reliability in microelectronic design.

Investigation of burr formation and its influence in micro-drilling hole of flexible printed circuit board

Circuit World ◽  
2020 ◽  
Vol 46 (4) ◽  
pp. 221-228
Author(s):  
Zhiyuan Li ◽  
Lijuan Zheng ◽  
Chengyong Wang ◽  
Xin Huang ◽  
Jiechi Xie
Keyword(s):  
Formation Mechanism ◽  
Thrust Force ◽  
Circuit Board ◽  
Hole Drilling ◽  
Hole Quality ◽  
Content Type ◽  
Burr Height ◽  
Printed Circuit ◽  
Flexible Printed Circuit ◽  
Micro Hole

Purpose The flexible printed circuit (FPC) board with the characteristic of light and thin strengthened confronted the growing miniaturization requirements of the electronic product and the popularity of wearable devices. The reliability of circuit could be influenced by the hole quality of FPC, such as burrs, which is one of the major problem in FPC. Design/methodology/approach In this paper, micro-drill with a diameter of 0.1 mm was used to drill the double-sided flexible copper clad laminate. The thrust force, the burr and tool wear were investigated. The influencing factors of the height of the burrs were studied. The relationship between the thrust force and the height of the burrs was also explored. Finally, the formation mechanism of burrs was analyzed. Findings The entrance burrs were usually less than the exit burrs. The burr height increased with the feed per rotation. The height of the burr increased with the increase of the thrust force for the plastic deformation of the copper foil was dominant. The abrasion of the drill gave rise to increase the height of burr. In micro-hole drilling, the growth of burrs can be suppressed effectively by reducing the clearance between the FPC and the backup plate. The thrust force would be controlled in a certain range to reduce the burr with specific drilling parameters. There existed a certain relationship of Gaussian distribution between the height of the burrs and the thrust force of FPC. Originality/value The reliability of the integrated circuit was directly affected by the burrs of the FPC. This research on the formation mechanism of FPC burrs and forecast of burr height provided a firm foundation for further work in the area of improvement of the micro-hole quality.

The entry drilling process of flexible printed circuit board and its influence on hole quality

Circuit World ◽  
2015 ◽  
Vol 41 (4) ◽  
pp. 147-153 ◽  
Author(s):  
Lijuan Zheng ◽  
Chengyong Wang ◽  
Xin Zhang ◽  
Yuexian Song ◽  
Lunqiang Zhang ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Drilling Process ◽  
Hole Quality ◽  
Location Accuracy ◽  
Content Type ◽  
Printed Circuit ◽  
Flexible Printed Circuit ◽  
Micro Drilling ◽  
Micro Hole

Purpose – The purpose of this study is to present the entry drilling process of flexible printed circuit board (FPCs) and its influence on hole quality, especially hole location accuracy. Compared with the traditional PCB drilling process, the technology of drilling FPCs is facing more problems, such as hole location accuracy, smear on the hole wall surface, burned hole wall surface, etc. Moreover, the materials of FPCs are quite different from the rigid printed circuit boards (RPCs). FPCs no longer contain glass fiber cloths to reinforce resin, resulting in flexibility. Micro-hole quality is the most important issue in FPC drilling. Suggestions were given to obtain higher hole qualities and higher FPC reliability. Design/methodology/approach – The entry drilling process of FPC with different kind of entry boards was observed by a high-speed camera. The hole qualities of FPC micro-drilling, especially hole location accuracy and hole entrance quality, were measured. The relationship between entry boards and hole quality was analyzed. Findings – Significant sliding occurred when drilling FPC with using no-entry board or pure aluminum plate entry board. On the contrary, no significant sliding occurred when using LC-110 or resin-coated aluminum foil (MVC) entry boards. The type, thickness and use-pattern of entry boards influenced hole location accuracy of FPCs seriously. In addition, entry board also influenced the micro-hole entrance quality and micro-hole diameter. The entrance quality of drilling FPC with LC-110 entry board was the best. The diameter variation of drilling FPC with MVC entry board was the smallest. The hole location accuracy decreased as the thickness of entry board increased. Thus, the best use-pattern of entry board was putting a LC-110 under MVC entry board, resulting in best entrance quality and hole location accuracy. Originality/value – The technology and manufacturing of FPCs in China are obviously behind. Research of FPCs micro-drilling and research data are lacking so far. Thus, it is most necessary to improve the technology level of FPCs micro-drilling in China. Researches on hole quality, especially hole location accuracy of FPCs drilling, were performed in this paper. Suggestions were given to obtain higher hole quality of FPCs.

Model updating of a temperature field simulation of a printed circuit board assembly based on the Kriging model

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yutian Yin ◽  
Hongda Zhou ◽  
Cai Chen ◽  
Yi Zheng ◽  
Hongqiao Shen ◽  
...  
Keyword(s):  
Response Surface ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit Board Assembly ◽  
Content Type ◽  
Printed Circuit ◽  
Soldering Process ◽  
New Strategy ◽  
Circuit Board Assembly ◽  
Actual Profile

Purpose The simulated temperature profile of the printed circuit board assembly (PCBA) during reflow soldering process deviates from the actual profile. To reduce this relative deviation, a new strategy based on the Kriging response surface and the Multi-Objective Genetic Algorithm (MOGA) optimizing method is proposed. Design/methodology/approach The simulated temperature profile of the PCBA during reflow soldering process deviates from the actual profile. To reduce this relative deviation, a new strategy based on the Kriging response surface and the MOGA optimizing method is proposed. Findings Several critical influencing parameters such as temperature and the convective heat transfer coefficient of the specific temperature zones are selected as the correction parameters. The hyper Latins sampling method is implemented to distribute the design points, and the Kriging response surface model of the soldering process is constructed. The updated model is achieved and validated by the test. The relative derivation is reduced from the initial value of 43.4%–11.8% in terms of the time above the liquidus line. Originality/value A new strategy based on the Kriging response surface and the MOGA optimizing method is proposed.

scholarly journals Flexible Printed Circuit Board as Novel Electrodes for Acoustofluidic Devices

2020 ◽  
pp. 1-6
Author(s):  
Chao Sun ◽  
Roman Mikhaylov ◽  
Yongqing Fu ◽  
Fangda Wu ◽  
Hanlin Wang ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit ◽  
Flexible Printed Circuit

Optimized Positional Compensation Parameters for Exposure Machine for Flexible Printed Circuit Board

2015 ◽  
Vol 11 (6) ◽  
pp. 1366-1377 ◽  
Author(s):  
Jinn-Tsong Tsai ◽  
Chorng-Tyan Lin ◽  
Cheng-Chung Chang ◽  
Jyh-Horng Chou
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit ◽  
Flexible Printed Circuit

Evaluation of new technologies and materials for printed circuit boards with improved heat dissipation properties

Circuit World ◽  
2016 ◽  
Vol 42 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Michal Baszynski ◽  
Edward Ramotowski ◽  
Dariusz Ostaszewski ◽  
Tomasz Klej ◽  
Mariusz Wojcik ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Printed Circuit Boards ◽  
Heat Dissipation ◽  
Printed Circuit Board ◽  
New Technologies ◽  
Electronic Device ◽  
Circuit Board ◽  
New Materials ◽  
Content Type ◽  
Printed Circuit

Purpose – The purpose of this paper is to evaluate thermal properties of printed circuit board (PCB) made with use of new materials and technologies. Design/methodology/approach – Four PCBs with the same layout but made with use of different materials and technologies have been investigated using thermal camera to compare their thermal properties. Findings – The results show how important the thermal properties of PCBs are for providing effective heat dissipation, and how a simple alteration to the design can help to improve the thermal performance of electronic device. Proper layout, new materials and technologies of PCB manufacturing can significantly reduce the temperature of electronic components resulting in higher reliability of electronic and power electronic devices. Originality/value – This paper shows the advantages of new technologies and materials in PCB thermal management.

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