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.
Technical Library | 2019-04-11 06:04:49.0
With the development of science and technology, the climatic chamber quality has been improved, and the failure rate is reduced, but there still have the failure probability.today we introduce what are the mian factors for big noise high low temperature test chamber: 1.External factors: the bottom angle is uneven, the ground is uneven, adjust the bottom angle, ensure the equipment is in a horizontal position; 2.The equipment is touched other objects or pushed against the wall,pls remove the objects and keep a certain distance from the wall. 3.Compressor noise:check whether the compressor collides with the pipeline,and evaporator dish is loose or not. 4.Check whether compressor shock absorbers are aging and replace them. 5.Solenoid valve noise: solenoid valve reversing caue loud sound, pls add damping glue, if no effect, need to replace solenoid valve. If there is AC noise, need to replace the power board. 6.Check wether the fan or the fan string shaft make noise,whether the fan blades are touched and deformed, whether the fan is fixed or not, pls adjust accordingly or add the rubber pad. If further technical questions,contact us without hesitation!---Climtest Symor® technical team
Technical Library | 2019-05-08 00:04:49.0
It is necessary to know there are some faults that cannot be entirely avoided during the use of temperature and humidity test chamber, but how to deal with them in time is a problem that needs to be paid attention to.Here mainly explain the temperature and humidity test chamber compressor in the reason for the water, and how to deal with it. Reason: water comes from air, because there is always water in the air, known as humidity, which is compressed into supersaturated air and then analyzed to become liquid. The oil comes from the lubrication system of the compressor, possibly because the wear clearance of the mechanism increases, and the lubricating oil will escape into the cylinder. Solution: after the compressor is removed from the temperature and humidity test chamber, with a larger gas storage tank, the oil and water will naturally settle down to the bottom of the jar, and we need to discharge regularly to reduce the oil and water content in the compressed air. Of course, you can also use filters and other things to further reduce the content of oil and water. if you need to know more details about climatic chamber, keep an eye on our website www.climatechambers.com
Technical Library | 2021-07-13 19:59:34.0
We have investigated the processing of lead-zirconate-titanate-based thick films by inkjet printing Pb (Zr0.53Ti0.47)0.98Nb0.02O3 with a 6 mol% excess of PbO nanosized powder dispersed in water. Differentwaveforms were employed to determine the optimum size and shape of the drops. A uniform, defect-free pattern with dimensions of 4 mm × 4 mm can be printed using 20 V and a drop spacing of 20 μm. The inkjet-printed films were heated to 400 °C to remove the organics and subsequently sintered at 750 and 850 °C. The correlations between the density, grain size and electromechanical properties of the thick films and bulk ceramics are qualitatively discussed. A thickness coupling factor of 46% was obtained for a 15-μm-thick film sintered at low temperature of 850 °C, which is comparable to the value of the bulk ceramic with an identical nominal chemical composition. Our results are important for the economic and environmental-benign printing of piezoelectric materials applicable in variety of electronic devices, such as sensors, actuators, transformers, piezoelectric energy harvesters and transducers.
Technical Library | 2024-09-02 18:48:58.0
The conversion to higher temperature "Lead Free" assembly reflow conditions has created an increased awareness that entrapped or absorbed moisture is a frequent root cause of thermally induced delamination at assembly reflow. There are two connected failure modes from entrapped moisture; incomplete resin cross-linking resulting in premature resin decomposition and also severe Z axis expansion from "explosive vaporization of the entrapped moisture at elevated temperatures at assembly reflow". Ultimately, both result in delamination failure. Other papers have shown the negative effects of entrapped moisture before lamination including delamination, red color, reduced thermal reliability and increased high speed signal loss. In this paper, various materials were tested for moisture sensitivity during lamination. Tests were performed at varying lamination conditions including a pre-vacuum step and "kiss" step. Pressure and cure temperature parameters were evaluated for minimizing or eliminating the effect of trapped moisture. Also included are the results of inner layer moisture removal baking conditions and their effect on peel strength and thermal reliability.
Technical Library | 2016-07-28 17:00:20.0
Packaging trends enable disruptive technologies. The miniaturization of components reduces the distance between conductive paths. Cleanliness of electronic hardware based on the service exposure of electrical equipment and controls can improve the reliability and cost effectiveness of the entire system. Problems resulting from leakage currents and electrochemical migration lead to unintended power disruption and intermittent performance problems due to corrosion issues.Solvent cleaning has a long history of use for cleaning electronic hardware. Limitations with solvent based cleaning agents due to environmental effects and the ability to clean new flux designs commonly used to join miniaturized components has limited the use of solvent cleaning processes for cleaning electronic hardware. To address these limitations, new solvent cleaning agents and processes have been designed to clean highly dense electronic hardware.The research study will evaluate the cleaning and electrical performance using the IPC B-52 Test Vehicle. Lead Free noclean solder paste will be used to join the components to the test vehicle. Ion Chromatography and SIR values will be reported.
Technical Library | 2019-09-04 21:35:53.0
Since the European Directives, RoHS (Restriction of Hazardous Substances) and REACH (Registration, Evaluation, Authorization and Restriction of Chemicals), entered into force in 2006-7, the number of regulated substances continues to grow. REACH adds new substances roughly twice a year, and more substances will be added to RoHS in 2019. While these open-ended regulations represent an ongoing burden for supply chain reporting, some ability to remain ahead of new substance restrictions can be achieved through full material declarations (FMD) specifically the IPC-1752A Class D Standard (the "Standard"), which was developed by the IPC - Association Connecting Electronic Industries. What is important to the supply chain is access to user-friendly, easily accessible or free, fully supported tools that allow suppliers to create and modify XML (Extensible Markup Language) files as specified in the Standard. Some tools will provide enhancements that validate required data entry and provide real-time interactive messages to facilitate the resolution of errors. In addition, validation and auto-population of substance CAS (Chemical Abstract Service) numbers, and Class D weight rollup validation ensure greater success in the acceptance of the declarations in customer systems that automate data gathering and reporting. A good tool should support importing existing IPC-1752A files for editing; this capability reduces the effort to update older declarations and greatly benefits suppliers of a family of products with similar composition. One of the problems with FMDs is the use of "wildcard" non-CAS numbers based on a declarable substance list (DSL). While the substances in different company's lists tend to have some overlap, no two DSL’s are the same. We provide an understanding of the commonality and differences between representative DSLs, and the ability to configure how much of a non-DSL substance percent is allowed. Case studies are discussed to show how supplier compliance data, can be automatically loaded into the customer's enterprise compliance system. Finally, we briefly discuss future enhancements and other developments like Once an Article, Always an Article (O5A) that will continue to require IPC standards and supporting tools to evolve.
Technical Library | 2019-05-06 23:13:09.0
Temperature and humidity test chamber has brought a lot of help to many industrial enterprises, but while it brings convenience to us, we should also take good care of them, otherwise they may be brought into the end-of-life phase ahead of time. The way of maintenance is also very simple. After daily use, the equipment is cleaned regularly, but the cleaning of the test chamber is also very skillful. If the operation is wrong, it may also lead to equipment failure. Let‘s learn how to extend the service life of the temperature and humidity test box together. 1, Pls clean the working room with water after each use, then dry the interior with dry cotton cloth. 2, Pls regularly remove dust from the evaporator inside the equipment, and periodically wipe the equipment to ensure clean and tidy. 3, When doing the test, the sample should be uniformly placed onto sample shelves,and the vent should not be blocked to prevent the influence of the test 4, It is necessary to pay attention to the cleaning of water tanks in peacetime, after the test or when the equipment is not intended to be used for a long time, all the water in the tank should be discharged, otherwise it will lead to the formation of scale inside the tank. The water used in the temperature and humidity test chamber must be pure or distilled water, or long-term use may result in a humidifier or internal pipe clogging. Above are the usual use notice of temperature and humidity test chamber, if customer adhere to the above several points,it is really able to prolong the service life of the equipment.
Technical Library | 2019-11-20 22:44:25.0
Salt spray test chamber is used to test teh salt corrosion resistance ability of hardware, metal and other auto parts,the chamber can quickly detect the corrosion resistance degree of products in the temperature, humidity and salt spraying environment, which can effectively improve production efficiency. So what is the reason why such a salt spray test chamber does not spray? As per our past maintenance experience,there are below reasons,customers can have a look,hope it is helpful: 1, the spray tower is blocked; 2, water pipes clogged, water flow can not go in; 3, the air compressor stops running,pls open the air compressor button; 4, main switch of the air compressor outlet is not turned on,pls turn on. 5, the solenoid valve fails, the pressure meter is broken or the pressure is too low, pls check with Climatest and repair it. 6, when the nozzle is clogged, the nozzle should be carefully removed and cleaned,because it is fragile. 7, if the spray pressure is normal, the position of the nozzle glass is also correct, but what is the reason for not spraying? In this case, it is necessary to carefully observe whether there is dirt at the contact surface of the nozzle. If so, clean up the dirt and the spray can be carried out normally. That‘s all we‘re going to talk about today. If you have any questions, follow us on facebook, Please feel free to ask us questions.
Technical Library | 2021-07-27 14:54:26.0
Fast forward to current time. Today, our society embraces cleanliness. We expect, demand, and evaluate cleanliness in almost every aspect of our lives. We wash our cars and pets. We maintain high cleanliness standards in our hotels and public spaces. We require cleanliness in our restaurants and hospitals. We sanitize our hands throughout the day to prevent illness. We live in a clean-centric culture. While we drive clean cars, stay in clean hotels and eat clean food, there is one part of our life where we actually abandoned cleanliness. Many of the circuit assemblies that affect almost every aspect of our daily lives are no longer required to be clean. Even though our life experience confirms the link between cleanliness and reliability, happiness, health, and safety, circuit assemblies no longer maintain that "cleanliness is next to Godliness" status. This was not always the case. There was a time when virtually all circuit assemblies were cleaned. The removal of flux and other process-related contamination was commonplace. Cleaning was as normal as soldering. As we bring history into current time, one may relate the fall of Rome and its adoption of personal hygiene and the subsequent decline in human health to the large-scale abandonment of cleanliness expectations of circuit assemblies and the subsequent reliability issues it has created. How did this happen? Has history repeated itself?
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