Automatic opitcal through hole inspection method for printed wiring boards using leakage light detection

2005 ◽  
Author(s):  
M. Ando ◽  
K. Mita ◽  
T. Inagaki
Keyword(s):  
Printed Wiring Boards ◽  
Light Detection ◽  
Inspection Method ◽  
Through Hole

Quality Control of Micro-Drilled Hole Wall of PWBs Using Data-Mining

2005 ◽  
Author(s):  
Eiichi Aoyama ◽  
Toshiki Hirogaki ◽  
Keiji Ogawa ◽  
Tsuyoshi Otsuka ◽  
Katsutoshi Yamauchi
Keyword(s):  
Data Mining ◽  
Surface Roughness ◽  
Present Report ◽  
Weft Yarn ◽  
Hole Drilling ◽  
Printed Wiring Boards ◽  
Factors Affecting ◽  
Hole Wall ◽  
Using Data ◽  
Through Hole

In the manufacturing of printed wiring boards (PWBs), various methods have been developed in order to improve the circuit packaging density. Micro-drills are generally used to make smaller diameter through-holes in PWBs, which are desired for the miniaturization of equipment. However, a problem has emerged in that copper plating degraded by hole drilling can reduce the reliability of the electrical connection between layers. The surface roughness of drilled hole wall is one of the important factors affecting the plating quality. The purpose of the present report is to apply data-mining to the surface roughness data of drilled through-hole walls, and to elucidate the factors required to control the drilled hole quality. The following conclusions were obtained. (1) The data-mining aided by a computer was found to be effective to control the drilled hole wall quality in the PWBs manufacturing. (2) It was clear that the surface roughness of drilled hole walls depended on three factors: the drill temperature, cutting distance, and the width of the fiber bundle of weft yarn.

Through-Hole Drilling Condition of FR-4 Printed Wiring Boards Based on Preventing Ion Migration

2003 ◽  
Author(s):  
Eiichi Aoyama ◽  
Hiromichi Nobe ◽  
Tadayuki Ikuta ◽  
Tsutao Katayama ◽  
Toshiki Hirogaki ◽  
...  
Keyword(s):  
Feed Rate ◽  
Manufacturing Sector ◽  
Present Report ◽  
Hole Drilling ◽  
Glass Cloth ◽  
Printed Wiring Boards ◽  
Printed Wiring Board ◽  
Ion Migration ◽  
Hole Wall ◽  
Through Hole

In the printed wiring board manufacturing sector, methods have been developed to improve the circuit packaging density. A problem has emerged in that the quality of drilled through hole is deteriorating in the smaller diameter drilling of printed wiring boards (PWBs) with high packaging density, because the insulation is insufficient among through-holes after plating in finer circuit pattern. Thus, we have attracted attention to occurrence of delamination in the glass cloth around the drilled hole of FR-4 type PWBs, because it is considered that the poor insulation among through holes is caused by ion migration along the delamination of glass cloth. In the drilling hole to GFRP, Damage occurs from the drilled hole wall to the inside of material by peeling off between layers, it is defined as delamination in this study. In the present report, we describe the influence of drilling conditions on the width of delamination of glass cloth around the drilled hole. First, we made the FR-4 type PWBs (thickness 0.2 mm) reinforced by five kinds of glass cloths. We carried out the drilling experiments (spindle speed 33000rpm and feed rate 0.01–0.06 mm/rev) for these PWBs with diameter 0.4 mm drill tools. Second, we researched the relationship between delamination width and relative hole position for the glass cloth thickness by image processing method. As a result, we demonstrate two important factors (the feed rate conditions in drilling and the thickness of glass cloth at drilled hole wall) to prevent the delamination of glass cloth. The practical formula is proposed to predict the delamination width around the drilled hole by a multivariate analysis method.

Analysis of Catastrophic Field Failures Due to Conductive Anodic Filament (CAF) Formation

1998 ◽  
Vol 515 ◽  
Author(s):  
W. J. Ready ◽  
B.A. Smith ◽  
L.J. Turbini ◽  
S.R. Stock
Keyword(s):  
Ground Plane ◽  
Water Soluble ◽  
Potential Difference ◽  
Voltage Gradient ◽  
Printed Wiring Boards ◽  
Copper Salts ◽  
Electronic Products ◽  
Hot Air ◽  
Hostile Environments ◽  
Through Hole

ABSTRACTUnder certain environmental conditions, printed wiring boards (PWB) respond to applied voltages by developing subsurface deposits of copper salts extending from anode to cathode along separated fiber / epoxy interfaces. The formation of these deposits, termed conductive anodic filaments (CAF) require high humidity (80%RH) and high voltage gradient (5V/mil). The humidity exposure during the storage environment may cause the failure in the use environment. CAF formation is enhanced by the use of certain hot air solder leveling (HASL) fluids and / or water soluble flux constituents.In this work, two catastrophic field failures were analyzed. Both failures were related to boards produced in a manufacturing process, which included HASL. One CAF failure occurred between a component through-hole and power plane held at a potential difference of 40V with a 0.005″ nominal spacing. The other occurred on an inner layer of a multi-layer board (MLB) between a via and ground plane held at a potential difference of 320V with 0.015” nominal spacing. The nature of the CAF was analyzed using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Ion chromatography (IC) was used to identify residue extracted from a failed board. The failure phenomena known as CAF poses serious longterm reliability concerns in electronic products exposed to adverse and hostile environments, especially those with closely spaced conductors.

The use of ultrasonic guided waves for the inspection of square tube structures: Dispersion analysis and numerical and experimental studies

2020 ◽  
pp. 147592172091969 ◽  
Author(s):  
Xiang Wan ◽  
Meiru Liu ◽  
Xuhui Zhang ◽  
Hongwei Fan ◽  
Peter W Tse ◽  
...  
Keyword(s):  
Guided Waves ◽  
Plane Surface ◽  
Group Velocity Dispersion ◽  
Ultrasonic Inspection ◽  
Experimental Studies ◽  
Wave Mode ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Inspection Method ◽  
Through Hole

Square steel tubes have been widely used in buildings and machines in civil engineering. The inspection of square tubes is becoming increasingly urgent and important to ensure the safety of these buildings and machines. However, the current most frequently used traditional ultrasonic inspection method is time-consuming and inefficient when dealing with long square tubes. There is an urgent need to develop an efficient approach to inspect square tubes. In this article, the use of ultrasonic guided waves is proposed. Phase and group velocity dispersion curves of square tube structures are first derived using the semi-analytical finite element method. An appropriate guided wave mode used for inspecting square tubes is selected. Ultrasonic guided waves propagating in normal, in-plane surface-damaged, and edge-damaged square tubes are numerically studied. It is illustrated that the monitoring points are able to receive reflected wave signals from both the in-plane surface and the edge damages. Experimental studies are also conducted to study ultrasonic guided waves interacting with circular through-hole damages located in surfaces and slot damages at edges. It is shown that both the circular through-hole damages located in different surfaces and slot damages at different edges can be clearly detected by reflected guided wave packets. It is found that the signal-to-noise ratios have been significantly improved after applying impedance matching to piezoelectric wafer transducers. The results have shown that ultrasonic guided waves are a promising and effective method for the inspection of square tubes.

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