The best stability under all operating conditions is achieved by electrical rotary equipment (motors and generators) and static electrical equipment (transformers and sensors) if all the air trapped inside the wire windings is replaced with insulatio
Electronics Forum | Wed Apr 04 16:54:58 EDT 2007 | pjc
Maybe more baking time is needed. Topside board temp too low. Moisture trapped in board. Top of through hole capped by component and trapping flux. http://www.speedlinetech.com/electrovert/electrovert-troubleshooting/index.htm
Electronics Forum | Tue Jan 08 22:23:24 EST 2019 | kenneth0
Hi Prem, try take a few caps and bake them before assembling them to the board to see whether this problem goes away. Its a common problem these tentalum caps can outgas if there's moisture trapped within. Once verified that moisture is the culprit
Industry News | 2021-05-19 22:36:33.0
Calibration is the process of configuring an instrument to provide a result for a sample within an acceptable range. This process eliminated or minimized factors that cause inaccurate measurements. Although the exact procedure may vary from product to product, the calibration process generally involves using calibration instrument to test samples of one or more known values called "calibrators". The results are then used to establish a relationship between the measurement technique used by the instrument and the known values. The process in essence "teaches" the instrument to produce results that are more accurate than those that occur otherwise. The instrument can then provide more accurate results when samples of unknown values are tested in the normal usage of the product.
Industry News | 2017-04-11 21:21:11.0
KYZEN today announced plans to participate in the Contamination, Cleaning & Coating Conference, scheduled to take place May 22-24, 2017 in Amsterdam. The event is co-organized by SMTA and SMART Group. Mike Bixenman, DBA, KYZEN Corporation will present “Development of a Risk Profile from Flux Residues Trapped under Leadless Components” in Session I entitled “Residues Trapped under Component Terminations”. All presentations in this session will address a common question faced by OEMs when designing electronic hardware: How clean is clean enough?
Technical Library | 2023-09-23 22:29:02.0
Moisture trapped within components and PBs presents a serious problem during the fabrication and assembly process. Too much moisture can lead to board failures when it is turned to steam during the reflow process.
Technical Library | 2018-09-21 10:12:53.0
Moisture accumulates during storage and industry practice recommends specific levels of baking to avoid delamination. This paper will discuss the use of capacitance measurements to follow the absorption and desorption behaviour of moisture. The PCB design used in this work, focused on the issue of baking out moisture trapped between copper planes. The PCB was designed with different densities of plated through holes and drilled holes in external copper planes, with capacitance sensors located on the inner layers. For trapped volumes between copper planes, the distance between holes proved to be critical in affecting the desorption rate. For fully saturated PCBs, the desorption time at elevated temperatures was observed to be in the order of hundreds of hours. Finite difference diffusion modelling was carried out for moisture desorption behaviour for plated through holes and drilled holes in copper planes. A meshed copper plane was also modelled evaluating its effectiveness for assisting moisture removal and decreasing bake times. Results also showed, that in certain circumstances, regions of the PCB under copper planes initially increase in moisture during baking.
SMTnet Express, July 20, 2017, Subscribers: 30,612, Companies: 10,637, Users: 23,528 Reactivity Of No-Clean Flux Residues Trapped Under Bottom Terminated Components Bruno Tolla, Ph.D., Jennifer Allen, Kyle Loomis - Kester Corporation , Mike
ASYMTEK Products | Nordson Electronics Solutions | https://www.nordson.com/en/divisions/sonoscan/support/application-notes/0434-pqfp-production-scanning
. The circular gap-type defect pattern surrounding the die is typical of a popcorn crack resulting from the sudden expansion of trapped moisture
ASCEN Technology | https://www.ascen.ltd/Blog/Solutio/602.html
surface insulation resistance but will also allow any moisture trapped in the circuit board to escape. The concept of a conformal coating of electronics was originally proposed,after the conformal coating machine application more and more popular, and through research to meet the demanding requirements
