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Multi-Objective Optimization of Mn-Doped Tio2 Content for Wettability, Printability and Intermetallic Layer of Sac305 Pb-Free Solder Paste on a Cu Substrate
(2021-12-01)
Kanlayasiri, K.
;
Ariga, T.
Effects of Mn-doped TiO<inf>2</inf> nanoparticles on the wettability, printability and thickness of intermetallic layer of SAC30 on a Cu substrate were studied in this paper. Concentration of Mn-doped TiO<inf>2</inf> nanoparticles was varied from 0.05 wt.% to 1wt.%. The wettability was evaluated in terms of contact angle of solder on the copper substrate and the printability was measured from the volume ratio of printed solder on the copper substrate to volume of stencil opening. The experimental results showed that 0.10wt.% Mn-doped TiO<inf>2</inf> led to the lowest contact angle while the printability was decreased with the increase of the added nanoparticles and the thinnest intermetallic layer was found at 0.50wt.% Mn-doped TiO<inf>2</inf> nanoparticles. Mn-doped TiO<inf>2</inf> concentration was then optimized using a desirability function to find optimal values for the three responses. It was found that 0.07wt.% was the optimal concentration for the three metrics — wettability, printability and thickness of the intermetallic layer.
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Wettability and printability of SAC305-xTiO2 Pb-free solder paste on Cu substrate
(2019-10-28)
Sukpimai, K.
;
Suwannakrue, W.
;
Kanlayasiri, K.
This paper was aimed to study on effects of TiO<inf>2</inf> nanoparticles on wettability and printability of SAC305-xTiO<inf>2</inf> Pb-free solder on Cu substrate. TiO<inf>2</inf> nanoparticles at various concentrations (0.00, 0.05, 0.10, 0.50, and 1.00 wt%) were introduced to SAC305 solder paste by mechanical mixing. Wettability of the solder on Cu substrate was measured in terms of contact angle while printability was calculated from the ratio of printed volume on Cu substrate to ideal volume of solder on the substrate. Results showed that the introduction of TiO<inf>2</inf> nanoparticles decreases the contact angle and 0.33 wt% TiO<inf>2</inf> is the optimal concentration providing the lowest contact angle within the experimental range. Moreover, the addition of TiO<inf>2</inf> nanoparticles reduced the printability of solder paste on Cu substrate. The higher amount of nanoparticles gave the lower printability. Simultaneous optimization on wettability and printability was also performed to find the optimal TiO<inf>2</inf> concentration.
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Experimental Study on Failure Mechanism of Advanced High Strength Steels in Air Bending Process
(2018-06-04)
Pornputsiri, N.
;
Kanlayasiri, K.
This research investigated the failure phenomena and underlying damage mechanisms in small curvature bending and spring-back angles of two advanced high strength steel (AHSS) sheets (TRIP780 and DP980). The study also examined the effect of the bending angle on the failure mechanism. In the analysis, this research utilized an optimal microscope (OM), scanning electron microscope (SEM) and energy-dispersive X-ray spectroscope (EDX). The research findings indicated that the bending force and the bending angle were positively correlated and that the spring-back and bending angles were inversely correlated. On the failure mechanism, at the 45° bending angle, the initial crack was identified on the outer region of the LD-rolling DP980 sheet, while no visible crack emerged for the TD-rolling TRIP780 until arriving at the 60° bending angle, indicating that, by comparison, the former possessed the lowest bendability and the latter the highest.
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Effects of copper content in Sn-based solder on the intermetallic phase formation and growth during soldering
(2018-06-04)
Mookam, N.
;
Tunthawiroon, P.
;
Kanlayasiri, K.
This research has studied the effects of copper contents in the Sn-based solder (i.e. Sn-0.7Cu, Sn-1.0Cu, and Sn-3.0Cu) on the intermetallic phase formation and the growth during soldering. In the experiments, reflow soldering was performed at 350 °C with the Cu substrate by using three solders for various soldering times of 10, 20, 40, 60, 120, 240 and 480 s. XRD data have shown that the η-Cu<inf>6</inf>Sn<inf>5</inf> and ϵ-Cu<inf>3</inf>Sn phases with hexagonal crystal structure were present between the solder and the substrate. The presence of ϵ-Cu<inf>3</inf>Sn phase was found only when the substrate was soldered for at least 240 s. The Cu content in solder had significant effects on the intermetallic growth with long term soldering time. In addition, the diffusion coefficient was correlated to the Cu content in the solder.
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Improving the performance of EDM deep hole using multi-hole interior flushing electrode
(2018-06-04)
Chuvaree, S.
;
Kanlayasiri, K.
In conventional flushing, when increasing the machining depth, the flushing ability becomes insufficient for ejection of the debris from machining gap. Debris concentration in the gap spark causes a process instability, low performance and high machining time etc. This paper proposes an innovative method of flushing technique for electrical discharge machining (EDM) of deep hole process. Tool electrode was specifically fabricated for flushing on the efficiency and stability of machining to promote the ejection of debris from machining gap. The performance of the deep hole process by electrical discharge machining under different flushing condition are presented. The results showed that the flushing through the tool electrode and multi-hole interior flushing are more preferred than side flushing. The result include 26.10% reduction in machining time (50 mm. in depth) when using multi-hole interior flushing electrode. In addition, the application of electrode multi-hole interior flushing electrode with electrode rotation improves the material removal rate (MRR) by 35.28% with 58.04% higher surface roughness (Ra).
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Influences of solid-state brazing conditions on microstructure and tensile shear force of Ag-Cu-P brazed copper sheets
(2018-06-04)
Jattakul, P.
;
Kanlayasiri, K.
This study aimed to examine the tensile shear force and microstructure of copper sheets when Ag-Cu-P filler metal was applied for the joints involved in the production of laminated micro-channel array (LMA) devices. The properties of the microstructure of the Ag- Cu-P/copper brazed joints were examined following a process which included furnace brazing, with the parameters comprising temperature, holding time, and loading pressure. Analytical tools included an energy dispersive spectrometer (EDS), scanning electron microscope (SEM) and X-ray diffraction analysis (XRD). In addition, tensile tests were performed to measure the tensile shear force. It was difficult to observe the Cu<inf>3</inf>P which forms along with the layer between the Ag-Cu-P filler metal and the copper sheet when the brazing temperature was only 580°C since this allowed gaps to form within the joint, thus producing very low tensile shear force results. When the brazing temperature is increased to 620°C along with longer holding time and increased pressure, this allows a thicker phase of Cu<inf>3</inf>P to form in the brazing joint. With a holding time of 30 minutes and pressure of 12.173 kPa, tensile shear force was maximized since this condition produced thick Cu<inf>3</inf>P phase. It is apparent that it is possible to produce a brazed joint which has an average shear force of 736.27 N under these conditions as described above. Within the joint could be found a Cu<inf>3</inf>P phase with no brittle phase.
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Optimizing the resistance spot-welding process for dissimilar stainless steels
(2018-06-04)
Khuenkaew, T.
;
Kanlayasiri, K.
The objective of this study was to identify the ideal welding circumstances to conduct resistance spot-welding in the case of 316 austenite and 425 ferrite stainless steels, which offer the challenge of being dissimilar. The study examines a number of welding variables, including weld current, weld time, hold time, electrode force, and the upper and lower electrode types. Initially, a 2<sup>6-1</sup> fractional factorial design was used for the screening of variables involved in the process. After this stage, the Box-Behnken design was employed for analysis of those variables and in order to specify the multiple response optimizations applicable to the size of nuggets through examination of the desirability function. The experiment was run using a resistance spot-welding machine at 50 kVA, 50 Hz. The quality of welded specimens was determined by their penetration, nugget diameter and nugget area. The optimal welding conditions were found to be 3.3 kN of electrode force, 25 cycles of weld time, 10,000 amperes of weld current, 50 cycles of hold time, and both R30 types of up-low electrodes. The optimal welding conditions provided nugget sizes of quality which were able to pass the specifications of the customer.
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Effects of wire-EDM machining variables on surface roughness of newly developed DC 53 die steel: Design of experiments and regression model
(2007-10-01)
Kanlayasiri, K.
;
Boonmung, S.
DC53 is a newly developed cold die steel from Daido Steel, Japan. It is an improvement over the familiar cold die steel SKD11. Because DC53 is a new die steel, only little information is available in literature for its machining characteristics. This paper presents an investigation of the effects of machining variables on the surface roughness of wire-EDMed DC53 die steel. In this study, the machining variables investigated were pulse-peak current, pulse-on time, pulse-off time, and wire tension. Analysis of variance (ANOVA) technique was used to find out the variables affecting the surface roughness. Assumptions of ANOVA were discussed and carefully examined using analysis of residuals. Quantitative testing methods on residual analysis were used in place of the typical qualitative testing techniques. Results from the analysis show that pulse-on time and pulse-peak current are significant variables to the surface roughness of wire-EDMed DC53 die steel. The surface roughness of the test specimen increases when these two parameters increase. Lastly, a mathematical model was developed using multiple regression method to formulate the pulse-on time and pulse-peak current to the surface roughness. The developed model was validated with a new set of experimental data, and the maximum prediction error of the model was less than 7%. © 2007.
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An investigation on effects of wire-EDM machining parameters on surface roughness of newly developed DC53 die steel
(2007-06-12)
Kanlayasiri, K.
;
Boonmung, S.
DC53 is a newly developed cold die steel from Daido Steel, Japan. It is an improvement over the familiar cold die steel SKD11. Because DC53 is a new die steel, only little information is available in literature for its machining characteristics. This paper investigated the effects of machining parameters on surface roughness of wire EDMed DC53 die steel. The investigated machining parameters were pulse-on time, pulse-off time, pulse-peak current, and wire tension. Analysis of variance (ANOVA) technique was used to find out the parameters affecting the surface roughness. Assumptions of ANOVA were discussed and then examined through residual analysis. Quantitative testing methods on residual analysis were employed in place of the typical qualitative testing techniques. Results from ANOVA show that pulse-on time and pulse-peak current are significant variables to surface roughness of wire-EDMed DC53 die steel. The surface roughness of test specimen increased as these two variables increased. © 2007.

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