A novel placement method for mini-scale passive components in surface mount technology

Author(s):  
Jingxi He ◽  
Yuqiao Cen ◽  
Yuanyuan Li ◽  
Shrouq M. Alelaumi ◽  
Daehan Won

2021 ◽  
Author(s):  
Jingxi He ◽  
Yuqiao Cen ◽  
Yuanyuan Li ◽  
Shrouq Alelaumi ◽  
Daehan Won

Abstract This paper aims to propose a novel placing method, i.e., place-between-paste-and-pad (PB), for mini-scale passive components to enhance electronic assembly lines' yield. PB means a component is designed to be placed at the midpoint between the pastes and pads on the length direction while it aligns with the pads' center on the width direction. An experiment that involves 12 printed circuit boards (PCB) is designed and conducted to get comparative results. Four PCBs are employed for place-on-pad (PP), place-on-paste (PPS), and PB separately. On each board, 375 resistors R0402M (0.40 mm X 0.20 mm) are assembled horizontally. To study the components' misalignment under various solder paste offset conditions in different placement methods, a stencil with 25 solder paste offset settings is utilized. Based on this experiment's results, PB has superior performance to the other two methods to minimize components' misalignment. Regarding the number of acceptable components when post-reflow offsets are within 25% of components' dimensions, PB and PP have equivalent performances, and they both outperform PPS. Furthermore, PB is a low-cost placing strategy because PB needs not the real-time communication between the solder paste inspection machine and the pick-and-place machine. With the miniaturization trend in electronic products, the post-reflow components' misalignment is more frequently observed than before. The placement method proposed in this study is expected to offer a low-cost exploration in the component pick-and-place procedure to enhance the surface mount technology (SMT) assembly quality.



2019 ◽  
Vol 32 (1) ◽  
pp. 48-54 ◽  
Author(s):  
Rafiq Asghar ◽  
Faisal Rehman ◽  
Ali Aman ◽  
Kashif Iqbal

Purpose Low relative humidity (RH) effect surface mount devices in numerous ways. The smaller size (0201) capacitor and resistor start wasting when RH is low. Due to low RH, electrostatic charges built-up on the surface of surface mount devices (SMDs) and component’s reel. The positive charged SMDs stick with the negatively charged reel tape and are wasted. This paper comprehensively explores the environmental effects on 0201 size surface mount devices during mounting process. Different type and size of surface mount devices are tested in low and desired RH to validate the effectiveness of the proposed approach. This paper will also highlight high electrostatic discharge (ESD) due to low RH which can be detrimental for small size surface mount devices. The experimental and graphical illustrations will stipulate the results of success rate for mounting components. The effect on ESD, subsequently varying temperature and humidity will also be analyzed. Design/methodology/approach In this paper, 0201 SDMs will be considered for analysis. The surface mount technology (SMT) plant temperature and humidity has been varied to examine the properties of small size SMDs. Total 5 hours production data are collected from Laptop motherboard production environment. This approach is applicable to all SMT environment. Findings The authors reduced the wastage of 0201 chip size resistor and capacitor. Total 11 components are selected of this size, and there success rate is observed during mounting. These components are first observed in harsh environment where the temperature is first set to 20ºC and RH is set to 25 per cent. The success rate of these components is very low due to component’s wastage. When the plant temperature is set to 25ºC and RH is set to 45 per cent, the success rate of mounting increased up to 100 per cent. A single component placement success rate with respect to RH is observed for one month. The results are shown in Table IV. It can be seen that the success rate is near 100 per cent when RH and temperature is maintained in production environment. To eliminate the ESD build-up in material and equipment in manufacturing environment humidification is a very effective way. When the RH is kept to 45 per cent, the moisture content of the air is a natural conductor and earths any ESD in environment. Originality/value Experimental data have been obtained from Laptop motherboard manufacturing process to validate the effectiveness of proposed approach.





1991 ◽  
Vol 113 (2) ◽  
pp. 200-200 ◽  
Author(s):  
Carmen Capillo ◽  
A. J. Rafanelli




1995 ◽  
Vol 7 (2) ◽  
pp. 27-32 ◽  
Author(s):  
I. Artaki ◽  
A.M. Jackson ◽  
P.T. Vianco


Sign in / Sign up

Export Citation Format

Share Document