Technical Library | 2023-02-13 18:56:42.0
This paper describes the results of an intensive whisker formation study on Pb-free assemblies with different levels of cleanliness. Thirteen types of as-received surface-mount and pin-through-hole components were cleaned and intentionally contaminated with solutions containing chloride, sulfate, bromide, and nitrate. Then the parts were assembled on double-sided boards that were also cleaned or intentionally contaminated with three fluxes having different halide contents. The assemblies were subjected to high-temperature/high-humidity testing (85_C/85% RH). Periodic examination found that contamination triggered whisker formation on both exposed tin and solder fillets. Whisker occurrence and parameters depending on the type and level of contamination are discussed. Cross-sections were used to assess the metallurgical aspects of whisker formation and the microstructural changes occurring during corrosion.
Technical Library | 2019-11-17 22:46:45.0
Overview of walk-in temperature and humidity chamber: It also belongs to environmental test equipment, it tests whether the product can resist high temperature, low temperature, humidity, or the physical and chemical changes produced under extreme conditions, the walk-in temperature and humidity chamber volume is large, the product is placed, or a large object can be placed, such as automobile, new energy, television and liquid crystal screen, etc. How to do the routine maintenance of the walk-in temperature and humidity chamber: 1. The wet gauze basically, if there is no special case, s/b usually changed once in 3 months 2. The water channel shall be regularly cleaned, including water cup, water tank, etc., so as to prevent the water from being blocked,affect the humidity test. 3. It is forbidden to test the flammable and explosive products inside working room. 4. Clean the chamber on a regular basis 2. How to operate walk-in temperature and humidity chamber: The operation method is same as standard temperature humidity test chamber,the controller is 7-inch LCD programmable color screen, you only need to setthe temperature point---test time--how many cycles need to be tested, This can be done automatically, and the machine will stop automatically when it is complete. If there is any problem during the operation, the corresponding problem point will be displayed on the machine control screen. Walk-in temperature and humidity chamber is a must equipment for reliability test of Automobile,Aerospace,Electronic parts,etc,the operation and maintenance are easy,it is teh tear down mahcine,Climatest engineers will be dispatched to do on-site support,for instance,we will finish commissioning,train customers how to operate,maintain,welcome to follow our company facebook page:https://www.facebook.com/Climatechambers
Technical Library | 2019-05-16 02:25:15.0
limatest Symor wants to tell you that humidity is not only the most important thing in the chamber, but also the temperature In order to facilitate customers to add water, our temperature and humidity test chamber is to place the water tank at back of the equipment.Just open the baffle to see the water tank and the water level meter next to the tank,then add enough water to the tank. However, in addition to manual water addition, our temperature and humidity test chamber has equipment that can automatically add water. Only by connecting the water pipe at the water filling port can it be automatically replenished when there is a shortage of water, which is suitable for high humidity test for a long time.
Technical Library | 2019-06-10 22:14:11.0
UV-Lamp Weathering Test Chamber takes fluorescent UV lamps as light source to simulate the UV irradiation in natural light and condensation to conduct accelerated weathering test on the materials, It simulates UV, rain, high temperature, humidity, condensation, darkness and other environmental conditions, combine them together, and carry them out automatically.
Technical Library | 2019-10-29 02:55:33.0
For every 10 ℃ increase in temperature, the reaction rate is twice to three times. This means that for every 10 ℃ increase in temperature, the life span of the product will be halved, and when the temperature rises by 20 ℃, the life span of the product will be reduced to 1/4. High temperature will lead to aging, oxidation, evaporation, physical deformation and so on. Low temperature will lead to embrittlement, ice formation, viscosity and solidification degree, loss of mechanical strength, physical shrinkage and so on. When the product is shipped, stored and operated in the environment, it will be endangered. In addition, each product has regulatory and certification requirements, and it is important to evaluate reliability and durability before it is put on the market. In general, according to the IEC60068 test standard, it requires the volume of the laboratory to be at least five times the total volume of the sample under test. Haida constant temperature and humidity box can help you meet this demand. So with the fast developmement of manufacturing industry,test becomes a necessity to see wether the product is able to meet regulated standards in R&D satge,Climatest Symor specializes in handling temperature and humidity,we supply environmental test chamber to China State-owned Research Institutes and laboratories,and obtain excellent reputation from international cllients,our company put much efforts on chamber R&D ,striving to supply best-quality climate simulation equipment and after-sale service. For details,pls visit our official website www.climatechambers.com
Technical Library | 2018-05-09 22:15:29.0
Creep corrosion on printed circuit boards (PCBs) is the corrosion of copper metallization and the spreading of the copper corrosion products across the PCB surfaces to the extent that they may electrically short circuit neighboring features on the PCB. The iNEMI technical subcommittee on creep corrosion has developed a flowers-of-sulfur (FOS) based test that is sufficiently well developed for consideration as an industry standard qualification test for creep corrosion. This paper will address the important question of how relative humidity affects creep corrosion. A creep corrosion tendency that is inversely proportional to relative humidity may allow data center administrators to eliminate creep corrosion simply by controlling the relative humidity in the data center,thus, avoiding the high cost of gas-phase filtration of gaseous contamination. The creep corrosion relative humidity dependence will be studied using a modified version of the iNEMI FOS test chamber. The design modification allows the achievement of relative humidity as low as 15% in the presence of the chlorine-releasing bleach aqueous solution. The paper will report on the dependence of creep corrosion on humidity in the 15 to 80% relative humidity range by testing ENIG (gold on electroless nickel), ImAg (immersion silver) and OSP (organic surface preservative) finished PCBs, soldered with organic acid flux.
Technical Library | 2022-01-26 15:22:33.0
Reliability of conformal coatings used to mitigate tin whisker growth depends on their ability to contain tin whiskers. Two key material properties required to assess the reliability of a polyurethane coating are documented experimentally: adhesion strength and puncture strength. A modified blister test using a predefined blister area is employed to assess the adhesion strength and a puncture test is employed to evaluate the puncture strength of the coating. After measuring the properties at time zero, the coatings are subjected to accelerated testing conditions (high temperature/humidity storage and temperature cycling) and the degradations of the coating properties are documented.
Technical Library | 2017-07-27 16:51:57.0
Reliability Expectations of Highly Dense Electronic Assemblies is commonly validated using Ion Chromatography and Surface Insulation Resistance. Surface Insulation Resistance tests resistance drops on both cleaned and non-cleaned circuit assemblies. It is well documented in the literature that SIR detects ionic residue and the potential of this residue to cause leakage currents in the presence of humidity and bias. Residues under leadless components are hard to inspect for and to ensure flux residue is totally removed. The question many assemblers consider is the risk of residues that may still be present under the body of components.
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 | 2015-11-19 18:15:07.0
The move to lead free (Pb-free) electronics by the commercial industry has resulted in an increasing number of ball grid array components (BGAs) which are only available with Pb-free solder balls. The reliability of these devices is not well established when assembled using a standard tin-lead (SnPb) solder paste and reflow profile, known as a backward compatible process. Previous studies in processing mixed alloy solder joints have demonstrated the importance of using a reflow temperature high enough to achieve complete mixing of the SnPb solder paste with the Pb-free solder ball. Research has indicated that complete mixing can occur below the melting point of the Pb-free alloy and is dependent on a number of factors including solder ball composition, solder ball to solder paste ratio, and peak reflow times and temperatures. Increasing the lead content in the system enables full mixing of the solder joint with a reduced peak reflow temperature, however, previous research is conflicting regarding the effect that lead percentage has on solder joint reliability in this mixed alloy solder joint.
