Technical Library | 2022-09-25 20:03:37.0
Cracking remains the major reason of failures in multilayer ceramic capacitors (MLCCs) used in space electronics. Due to a tight quality control of space-grade components, the probability that as manufactured capacitors have cracks is relatively low, and cracking is often occurs during assembly, handling and the following testing of the systems. Majority of capacitors with cracks are revealed during the integration and testing period, but although extremely rarely, defective parts remain undetected and result in failures during the mission. Manual soldering and rework that are often used during low volume production of circuit boards for space aggravate this situation. Although failures of MLCCs are often attributed to the post-manufacturing stresses, in many cases they are due to a combination of certain deviations in the manufacturing processes that result in hidden defects in the parts and excessive stresses during assembly and use. This report gives an overview of design, manufacturing and testing processes of MLCCs focusing on elements related to cracking problems. The existing and new screening and qualification procedures and techniques are briefly described and assessed by their effectiveness in revealing cracks. The capability of different test methods to simulate stresses resulting in cracking, mechanisms of failures in capacitors with cracks, and possible methods of selecting capacitors the most robust to manual soldering stresses are discussed.
Technical Library | 2008-10-01 13:03:00.0
Many Original Equipment Manufacturers, (OEM’s), struggle to continue shipping aging or obsolete electronic products. Electronic products designed five to ten years ago are still relevant in the marketplace. Often these venerable old products have gained particular acceptance amongst a select group of customers. In many cases these old products fulfill a need in a unique manner. Examples include: designs that are grandfathered into an application due to regulatory considerations; designs having unique form-fit-and-function; designs running special software ; designs subject to contractual support and service requirements; designs in which a new contract stipulates delivery of older gear as part of a larger system offering. Any one or all of these reasons can lead an OEM to continue the production of electronic equipment well into its end of useful component life
Technical Library | 2008-12-03 19:39:00.0
This paper presents the analysis from a recent printing study employing a test vehicle that includes components such as 01005s to QFPs. In a recent publication, part of this study was presented focusing on 01005 printing only. This printing process was determined to be suitable for 01005s assembly and also analyzed based on statistical capability. The current paper will present the results from additional detailed analysis to determine if this process has the capability to provide sufficient solder paste deposits for larger components located on the same test board. In the future, the SMT industry may always look towards “Broadband Printing” as an alternative to dual stencil or stepped stencil printing technologies in order to meet the needs of both small and large components.
Technical Library | 2012-03-08 20:08:57.0
You may have heard talk in the news lately regarding counterfeit electronic components making it into the US military supply chain. The U.S. Senate Armed Services Committee (SASC) recently reported in the Counterfeit Electronic Parts in the Defense Department Supply Chain hearing held on November 17, 2011, 1,800 cases of suspected counterfeit components that went into more than 1 million individual products. If you consider this number for the military, we can only imagine the number of counterfeits in our commercial yet high reliability products, such as life support or other critical systems. If you are the person within your electronics-based company who must perform risk analyses, counterfeiting is not a new concern, yet many do not realize just how good counterfeiters have become at their "trade".
Technical Library | 2012-11-15 23:38:50.0
First published in the 2012 IPC APEX EXPO technical conference proceedings. As we progress in the 21st century, electronics manufacturing will need more and more precision. Parts will get more complex since more components have to be assembled in smaller spaces. Circuit boards and other electronic assemblies will become more densely populated; spacings between components will be shorter. This will require precision manufacturing and efficient cleaning during and post manufacturing. In addition, with population and technology progressing, larger amount of greenhouse gases will be emitted resulting in higher global warming. Intense research effort is going on to develop new generation of chemicals to address both cleaning and global warming issues. Low global warming solutions in refrigeration and as insulating agents are already in the marketplace.
Technical Library | 2014-09-04 17:43:19.0
The counterfeiting of electronic components has become a major challenge in the 21st century. The electronic component supply chain has been greatly affected by widespread counterfeit incidents. A specialized service of testing, detection, and avoidance must be created to tackle the worldwide outbreak of counterfeit integrated circuits (ICs). So far, there are standards and programs in place for outlining the testing, documenting, and reporting procedures. However, there is not yet enough research addressing the detection and avoidance of such counterfeit parts. In this paper we will present, in detail, all types of counterfeits, the defects present in them, and their detection methods. We will then describe the challenges to implementing these test methods and to their effectiveness. We will present several anti-counterfeit measures to prevent this widespread counterfeiting, and we also consider the effectiveness and limitations of these anti-counterfeiting techniques.
Technical Library | 2015-02-27 17:06:01.0
The drive towards fine pitch technology also affects the soldering processes. Selective soldering is a reliable soldering process for THT (through hole) connectors and offers a wide process window for designers. THT connectors can be soldered on the top and bottom side of boards, board in board, PCBs to metal shields or housing out of plastic or aluminum are today's state of the art. The materials that are used to make the solder connections require higher temperatures. Due to the introduction of lead-free alloys, the boards need more heat to get the barrels filled with solder. This not only affects the properties of the flux and components, but the operation temperatures of solder machines become higher (...)First the impact of temperature will be discussed for the separate process steps and for machine tooling. In the experimental part measurements are done to verify the accuracy that can be achieved using today's selective soldering machines. Dedicated tooling is designed to achieve special requirements with respect to component position accuracy.
Technical Library | 2016-10-24 14:59:03.0
Temperature measurement is one of the most important physical parameters when determining quality, accuracy and reliability of processes not only in industrial use, but also in almost all human activities. Temperature sensors are produced with different technologies to fit specific application requirements. IST AG has concentrated one part of the development and manufacturing on high-end thin-film temperature sensors. This know-how is partially derived from the semiconductor industry and allows us to manufacture sensors with high accuracy, excellent long-term stability, high reliability and repeatability within a wide temperature range from -200 °C up to 1000 °C. Because of very small dimensions and low thermal mass, the thin-film temperature sensors exhibit a very short response time.
Technical Library | 2017-01-19 16:58:47.0
The biggest problem with designing rigid-flex hybrid PCBs is making sure everything will fold in the right way, while maintaining good flex-circuit stability and lifespan. The next big problem to solve is the conveyance of the design to a fabricator who will clearly understand the design intent and therefore produce exactly what the designer/engineer intended.Rigid-Flex circuit boards require additional cutting and lamination stages, and more exotic materials in manufacturing and therefore the cost of re-spins and failures are very much higher than traditional rigid boards. To reduce the risk and costs associated with rigid-flex design and prototyping, it is desirable to model the flexible parts of the circuit in 3D CAD to ensure correct form and fit. In addition it is necessary to provide absolutely clear documentation for manufacturing to the fabrication and assembly houses.
Technical Library | 2017-09-25 10:36:52.0
Laser wire stripping was developed by NASA in the 1970s as part of the Space Shuttle program. The technology made it possible to use smaller sized wires with thinner insulations, without risk of the damage that can be caused by traditional mechanical wire stripping methods. Laser wire stripping technology was commercialized in the 1990s and was initially used for aerospace and defense applications. Laser wire stripping then grew significantly when the consumer electronics market exploded as lasers became the only stripping solution for the tiny data cables found in laptops, mobile phones and other consumer electronics products. Another large industry that has adopted laser wire stripping methods, and for good reason, is high-end medical device manufacturing.
