Stereoimaging Determination of Strains in Surface Mounted Components and Plated Through Holes Resulting from Thermal Cycung

1991 ◽  
Vol 226 ◽  
Author(s):  
David L. Davidson
Keyword(s):  
Printed Circuit Board ◽  
High Spatial Resolution ◽  
Circuit Board ◽  
Depth Of Field ◽  
Scanning Microscope ◽  
Printed Circuit ◽  
Plated Through Hole ◽  
Microelectronic Components ◽  
Through Hole

AbstractThe experimental mechanics of microelectronics components requires high spatial resolution measurements that are best obtained by using the scanning microscope because of the high spacial resolution and depth of field obtained using this instrument. This paper describes how measurements made from photographs taken in the scanning electron microscope have been used successfully to determine the strains which develop due to differences in coefficient of thermal between various parts of microelectronic components. Results are presented for thermal strains in the solder joints of a surface mounted component and in a printed circuit board plated through hole.

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.

scholarly journals HIGH-PERFORMANCE FLEXIBLE FORCE AND TEMPERATURE SENSING ARRAY WITH A ROBUST STRUCTURE

2013 ◽  
Vol 24 ◽  
pp. 1360014
Author(s):  
MIN-SEOK KIM ◽  
HAN-WOOK SONG ◽  
YON-KYU PARK
Keyword(s):  
High Performance ◽  
Sensor Array ◽  
Printed Circuit Board ◽  
High Spatial Resolution ◽  
Tactile Sensor ◽  
Circuit Board ◽  
Micro Fabrication ◽  
Printed Circuit ◽  
Flexible Printed Circuit ◽  
Physical Quantities

We have developed a flexible tactile sensor array capable of sensing physical quantities, e.g. force and temperature with high-performances and high spatial resolution. The fabricated tactile sensor consists of 8 × 8 force measuring array with 1 mm spacing and a thin metal (copper) temperature sensor. The flexible force sensing array consists of sub-millimetre-size bar-shaped semi-conductor strain gage array attached to a thin and flexible printed circuit board covered by stretchable elastomeric material on both sides. This design incorporates benefits of both materials; the semi-conductor's high performance and the polymer's mechanical flexibility and robustness, while overcoming their drawbacks of those two materials. Special fabrication processes, so called “dry-transfer technique” have been used to fabricate the tactile sensor along with standard micro-fabrication processes.

Fatigue Analysis of a Ceramic Pin Grid Array Soldered to an Orthotropic Epoxy Substrate

1991 ◽  
Vol 113 (2) ◽  
pp. 138-148 ◽  
Author(s):  
J. Lau ◽  
R. Subrahmanyan ◽  
D. Rice ◽  
S. Erasmus ◽  
C. Li
Keyword(s):  
Thermal Expansion ◽  
Solder Joint ◽  
Normal Stress ◽  
Printed Circuit Board ◽  
Thermal Stresses ◽  
Circuit Board ◽  
Thermal Expansion Mismatch ◽  
Stress Strain ◽  
Plated Through Hole ◽  
Through Hole

Thermal stresses and strains in the solder joints and plated-through-hole (PTH) copper pads/barrels of a pin-grid array (PGA) assembly under thermal cycling conditions have been determined in the present study. There are two major systems of thermal stresses/strains acting at the solder joint and copper. One is the transverse shear and vertical normal stress/strain due to the local thermal expansion mismatch between the pin, solder, copper, and FR-4. The other is the horizontal normal stress/strain due to the global thermal expansion mismatch between the ceramic PGA and the FR-4 printed circuit board (PCB). The effects of the local thermal expansion mismatch on the reliability of solder joint and PTH copper have been determined using a 3-D orthotropic-elastoplastic finite element method. The effects of the global thermal expansion mismatch on the reliability of solder joint and PTH copper have been determined by fatigue experiments. Fatigue life of the solder joint and PTH copper was then estimated based on the calculated strains and the fatigue data on solders and coppers.

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