Critical Soldering Interconnect Technology in SMT

2015 ◽  
Vol 713-715 ◽  
pp. 3001-3006
Author(s):  
Xiao Ming Hu
Keyword(s):  
Contact Angle ◽  
Circuit Board ◽  
Reflow Soldering ◽  
Surface Mount ◽  
Printed Circuit ◽  
Wave Soldering ◽  
Product Manufacturing ◽  
Interconnect Technology ◽  
Through Hole

this paper introduced the important soldering interconnect technology in SMT. In electric product manufacturing process, sometime we must place components in through-hole ways , then we use wave soldering. Wave soldering is used for both through-hole printed circuit assemblies, and surface mount. As technology changing very soon, the through-hole components have been largely replaced by surface mount components, this time ,Reflow soldering is the most common method of attaching surface mount components to a circuit board,but not wave soldering also reflowing, we must focus on wetting , It quantifies the wettability of a solid surface by a liquid .wetting angle is a the important quantity (also called contact angle).it can judge the quality of solder joints.

A study of the strength and shape of surface mount technology leadless chip solder joints

1997 ◽  
Vol 211 (1) ◽  
pp. 29-41 ◽  
Author(s):  
I. K. Hui ◽  
B Ralph
Keyword(s):  
Printed Circuit Boards ◽  
Failure Modes ◽  
Solder Joints ◽  
Circuit Board ◽  
Surface Mount Technology ◽  
Surface Mount ◽  
Printed Circuit ◽  
Wave Soldering ◽  
Infra Red

A method that directly pulled the components off printed circuit boards was used as a means for testing the bond quality of surface mount technology leadless chip solder joints. Components D7243, CC1206, RC1206, RC1210 and CC1812 were selected for the study. It was found that the ultimate tensile force that breaks a component off the printed circuit board has the potential to be used as a parameter for measuring the quality of the solder joint. The failure modes of the joints were recorded and are discussed. The effect of solder thickness on the strength of a joint has also been investigated. The shape of joints soldered by two methods, wave soldering and infra-red reflow, were compared. Joints at the two ends of a component produced by infra-red reflow were found to be more uniform than the ones produced by wave soldering. A recommendation is made here for the wave soldering approach in achieving uniform solder joints. The effects of solder shape on the joint strength were further investigated by finite element analysis. A convex joint was found to be marginally more robust than a concave joint.

Thermal Model of Printed Circuit Board Plated-Through Hole under One-Sided Heating Conditions

2021 ◽  
Vol 26 (5) ◽  
pp. 426-431
Author(s):  
V.A. Sergeev ◽  
◽  
A.M. Khodakov ◽  
M.Yu. Salnikov ◽  
◽  
...  
Keyword(s):  
Quality Control ◽  
Thermal Resistance ◽  
Thermal Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Thermal Models ◽  
Printed Circuit ◽  
Plated Through Hole ◽  
Through Hole

Thermal methods of quality control of the plated-through hole (PTH) of printed circuit board (PCB) are based on thermal models. However, known thermal models of PTH take no account of heat transfer to PCB material thus not allowing for PTH heat characteristic tying up with adhesion quality. In this work, an axisymmetric thermal model of a single-layer PCB PTH under one-sided heating conditions is considered. It was shown that the ratio of the temperature increments of the upper (heated) and lower end of the PTH in the considered range of heating power does not depend on the power level. A linear thermal equivalent scheme of the PTH has been proposed, which includes the longitudinal thermal resistance of the PTH metallization, de-termined by the parameters and quality of the metallization layer, the thermal resistance, which determines the convection heat exchange between the ends of the PTH with the adjacent PCB surface and the environment, and the thermal resistance of the area of the PCB material adjacent to the PTH, depending on the quality of the metallization adhesion and the PCB dielectric. Thermal equivalent circuit parameters determined by the ratio of the temperature increment of the upper and lower ends of the PTH and their difference can serve as the basis for the development of a nondestructive inspection procedure for PTH quality control by way of its unilateral heating, for example, by a laser beam.

Modeling of Errors Counting System for PCB Soldered in the Wave Soldering Technology

2014 ◽  
Vol 874 ◽  
pp. 139-143 ◽  
Author(s):  
Jacek Pietraszek ◽  
Aneta Gądek-Moszczak ◽  
Tomasz Toruński
Keyword(s):  
Quality Assurance ◽  
Experimental Design ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Counting System ◽  
Printed Circuit ◽  
Pcb Assembly ◽  
Wave Soldering ◽  
Soldering Technology ◽  
Through Hole

PartnerTech provides printed circuit board (PCB) assembly on request. Wired elements are assembled in through-hole technology and soldered on the wave soldering machine. The PCB with inserted elements is passed across the pumped wave of melted solder. Typically this process is accompanied by some class of defects like cracks, cavities, wrong solder thickness and poor conductor. In PartnerTech Ltd. another type of defects was observed: dispersion of small droplets of solder around holes. Quality assurance department plans to optimize the process in order to reduce the number of defects. In the first stage, it was necessary to develop a methodology for counting defects. This paper presents experimental design and analysis related to this project.

PB-Free Wave Soldering of Thick Printed Circuit Boards Using No-Clean VOC Free Flux

2007 ◽  
Author(s):  
Shantanu Mukherjee ◽  
Manuel Castro ◽  
Pei-Fang Jennifer Tsai ◽  
Krishnaswami Srihari ◽  
Van D. Nguyen
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Hole Filling ◽  
Process Step ◽  
Free Wave ◽  
Surface Mount ◽  
Printed Circuit ◽  
Wave Soldering ◽  
Hole Fill

There has been an increasing focus on surface mount technology, and the miniaturization of electronic assemblies. However, wave soldering still remains an integral part of the Printed Circuit Board (PCB) assembly process. Hole fill is an important aspect in wave soldering. It is caused by the capillary action of molten alloys, as the PCB traverses across the molten wave. The advent of Pb-free materials has tightened the process windows for wave soldering. This is primarily because Pb-free alloys have higher melting points. One way to enhance hole filling action is to increase the operating temperatures of the molten wave. This step, however, could result in the disintegration of surface mount or through hole devices, board discoloration and warpage. Flux selection is an important process step for Pb-free wave soldering as it enhances hole-fill and cleans the soldering surface of the oxides prior to the PCB hitting the wave. It is critical to use the ‘optimal’ flux in Pb-free wave soldering processes. The objective of this study is to determine the ‘best’ flux for the Pb-free wave soldering of 2.16mm (0.085″) thick PCBs with Ni/Au surface finish. The Pb-free solder in this application is SAC387 (95.5%Sn, 3.8%Ag, and 0.7% Cu) with VOC-free no clean water based flux. Under different conveyor speeds, the experimentation evaluates the ‘best’ flux among three candidates. Complete (100%) inspection using X-ray laminography equipment detects the percentage of hole fill and other defects such as bridging, flux residue, and solder balling. The ‘best’ flux should have the least number of defects.

Fabrication and surface treatment of fine copper lines for HDI printed circuit board with modified full-additive method

Circuit World ◽  
2017 ◽  
Vol 43 (3) ◽  
pp. 131-138 ◽  
Author(s):  
Huirong He ◽  
Jida Chen ◽  
Shengtao Zhang ◽  
Minhui Liao ◽  
Lingxing Li ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
High Efficiency ◽  
Oxidation Process ◽  
Optical Microscope ◽  
Circuit Board ◽  
Content Type ◽  
Printed Circuit ◽  
Additive Method ◽  
Fine Copper

Purpose This paper aims to propose a modified full-additive method (MFAM) to fabricate fine copper lines for high density interconnection (HDI) printed circuit boards (PCBs). In addition, the surface of the fine copper lines is treated with a brown oxidation process to obtain good adhesion between the copper and the dielectric resin. Design/methodology/approach Fine copper lines fabricated by MFAM were observed to evaluate the undercut quality, in comparison to undercut quality of copper lines fabricated by the semi-additive method and the subtractive method. The effect of the thickness of the dry film on the quality of the copper plating was investigated to obtain the regular shape of fine lines. The fine copper lines treated with the brown oxidation process were also examined to generate a coarse surface microstructure to improve the adhesion between the copper and the dielectric resin. The cross section and surface of as-fabricated fine copper lines were characterized using an optical microscope, a scanning electron microscope and an atomic force microscope. Findings MFAM has the potential to fabricate high-performance fine copper lines for HDI PCBs. Undercut of as-fabricated fine copper lines could be prevented to meet the design requirement of impedance. In addition, fine copper lines exhibit enough adhesive force to laminate with dielectric resin after the brown oxidation process. Originality/value MFAM, with the advantages of high efficiency and being a facile process, is developed to fabricate high-quality fine copper lines for industrial HDI PCB manufacture.

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