Technical Library | 2021-01-03 19:24:52.0
Reflow soldering is the primary method for interconnecting surface mount technology (SMT) applications. Successful implementation of this process depends on whether a low defect rate can be achieved. In general, defects often can be attributed to causes rooted in all three aspects, including materials, processes, and designs. Troubleshooting of reflow soldering requires identification and elimination of root causes. Where correcting these causes may be beyond the reach of manufacturers, further optimizing the other relevant factors becomes the next best option in order to minimize the defect rate.
Technical Library | 2021-09-15 18:53:20.0
Many printed circuit board assemblies (PCBAs) have relays that are soldered to the PCB. If such an electromechanical component fails, it can cause the whole device to fail, just like any other electronic component. The spectrum of root causes that lead to an increased contact resistance or a complete contact failure is totally different from what usually occurs in the electronics domain. This article provides a detailed analysis of these failures and the corresponding root causes, many of them self-centering.
Technical Library | 2023-01-23 20:50:05.0
PDC Outline Section 0: Intro Section 1: What is reliability and root cause? Section 2: Overview of failure mechanisms Section 3: Failure analysis techniques – Non-destructive analysis techniques – Destructive analysis – Materials characterization Section 4: Summary and closure
Technical Library | 2018-07-18 16:28:26.0
Reduction of first pass defects in the SMT assembly process minimizes cost, assembly time and improves reliability. These three areas, cost, delivery and reliability determine manufacturing yields and are key in maintaining a successful and profitable assembly process. It is commonly accepted that the solder paste printing process causes the highest percentage of yield challenges in the SMT assembly process. As form factor continues to get smaller, the challenge to obtain 100% yield becomes more difficult.This paper will identify defects affecting SMT yields in the printing process and discuss their Root Cause. Outer layer copper weight and surface treatment will also be addressed as to their effect on printability. Experiments using leadless and emerging components will be studied and root cause analysis will be presented
Technical Library | 2021-03-10 23:57:29.0
Latent short circuit failures have been observed during testing of Printed Circuit Boards (PCB) for power distribution of spacecraft of the European Space Agency. Root cause analysis indicates that foreign fibers may have contaminated the PCB laminate. These fibers can provide a pathway for electromigration if they bridge the clearance between nets of different potential in the presence of humidity attracted by the hygroscopic laminate resin. PCB manufacturers report poor yield caused by contamination embedded in laminate. Inspections show ...
Technical Library | 2021-09-15 18:44:20.0
Analyzing failures is a critical process in determining the physical root causes of problems. The process is complex, draws upon many different technical disciplines, and uses a variety of observation, inspection, and laboratory techniques. One of the key factors in properly performing a failure analysis is keeping an open mind while examining and analyzing the evidence to foster a clear, unbiased perspective of the failure.
Technical Library | 2009-10-14 21:17:47.0
Electrochemical migration (ECM) is defined as the growth of conductive metal filaments across a printed circuit board (PCB) in the presence of an electrolytic solution and a DC voltage bias. ECM, also known as dendritic growth, is a critical issue in the electronics industry because the intermittent failure behavior of ECM is a likely root-cause of the high occurrence of field failures identified as no trouble found (NTF)/could not duplicate (CND)
Technical Library | 2018-10-20 13:50:05.0
With this easy-to-use Troubleshooting Guide, you can learn to troubleshoot common SMT issues. After using it a few times, it will become an essential companion for you and anyone in your company responsible for operating an SMT line. This Guide offers troubleshooting advice for common SMT assembly issues by process defect. If your issue is not resolved after following the steps to help identify the possible root cause and solution, please contact your Cookson Electronics representative who will be able to provide you with further assistance.
Technical Library | 2006-10-26 08:08:00.0
There have been many studies of the causes of tombstoning; some published, some not. They tend to focus on a single process parameter as the root cause of tombstoning. However, there is no single process change that is a sure cure for tombstoning! Those that claim otherwise are either uninformed or trying to sell you something. Rather than limiting your view to a single solution, EFD recommends you heed all of the studies. Like pieces of a puzzle, each study does not reveal the whole picture, but looked at all together, the picture is clear.
Technical Library | 2013-02-07 17:01:46.0
Silicone contamination is known to have a negative impact on assembly processes such as soldering, adhesive bonding, coating, and wire bonding. In particular, silicone is known to cause de-wetting of materials from surfaces and can result in adhesive failures. There are many sources for silicone contamination with common sources being mold releases or lubricants on manufacturing tools, offgassing during cure of silicone paste adhesives, and residue from pressure sensitive tape. This effort addresses silicone contamination by quantifying adhesive effects under known silicone contaminations. The first step in this effort identified an FT-IR spectroscopic detection limit for surface silicone utilizing the area under the 1263 cm-1 (Si-CH3) absorbance peak as a function of concentration (µg/cm2). The next step was to pre-contaminate surfaces with known concentrations of silicone oil and assess the effects on surface wetting and adhesion. This information will be used to establish guidelines for silicone contamination in different manufacturing areas within Harris Corporation... First published in the 2012 IPC APEX EXPO technical conference proceedings.
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