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

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<jats:title content-type="abstract-subheading">Purpose</jats:title>
<jats:p>This study aims to investigate the interaction of independent variables [Reynolds number (<jats:italic>Re</jats:italic>), 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 <jats:italic>Re</jats:italic> 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).</jats:p>
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<jats:title content-type="abstract-subheading">Design/methodology/approach</jats:title>
<jats:p>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. <jats:italic>Re</jats:italic>, 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 <jats:italic>Re</jats:italic> for the different number of BGA packages attached to the FPCB.</jats:p>
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<jats:title content-type="abstract-subheading">Findings</jats:title>
<jats:p>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 <jats:italic>Re</jats:italic> and thermal power. Optimized <jats:italic>Re</jats:italic> for 1–3 BGA packages with maximum thermal power applied has been identified as 21,364, 23,858 and 29,367, respectively.</jats:p>
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<jats:title content-type="abstract-subheading">Practical implications</jats:title>
<jats:p>This analysis offers a better interpretation of the parameter control in FPCB with optimized <jats:italic>Re</jats:italic> for the use of force convection electronic cooling. Optimal <jats:italic>Re</jats:italic> could be used as a reference in the thermal management aspect in designing the BGA package.</jats:p>
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<jats:title content-type="abstract-subheading">Originality/value</jats:title>
<jats:p>This research presents the parameters’ effects on the reliability and heat transfer in FPCB design. It also presents a method to optimize <jats:italic>Re</jats:italic> for the different number of BGA packages attached to increase the reliability in FPCB’s design.</jats:p>
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