Technical Library | 2019-11-07 03:07:12.0
Many customers who have purchased the nitrogen cabinets have been in the mistaken belief that the air pipe can be pull down hard,so that it can cause the board to be damaged due to the hard pulling of the air pipe, which leads to the replacement of the penetrating board. Now, the following pictures are provided. Please note: Nitrogen cabinet is a optiomal choice for the microelectronics,semiconductor for humidity proof and anti-oxidation purpose,Climatest has put much efforts on the R&D of dry cabinets,as you know,our advangtage is to handle temperature and humidity,since early 1990s,our engineers began to test and research dry cabinet and nitrogen cabinet,all of our manufacturing process strictly follow ISO9001 standard,we supply to international customers for 20 years,if you are still looking for a reliable dry cabinet manufacturer to protect your MSD from moisture related damage,come to visit www.climatechambers.com,we are ready!
Technical Library | 2023-08-04 15:27:30.0
A designed experiment evaluated the influence of several variables on appearance and strength of Pb-free solder joints. Components, with leads finished with nickel-palladium-gold (NiPdAu), were used from Texas Instruments (TI) and two other integrated circuit suppliers. Pb-free solder paste used was tin-silver-copper (SnAgCu) alloy. Variables were printed wiring board (PWB) pad size/stencil aperture (the pad finish was consistent; electrolysis Ni/immersion Au), reflow atmosphere, reflow temperature, Pd thickness in the NiPdAu finish, and thermal aging. Height of solder wetting to component lead sides was measured for both ceramic plate and PWB soldering. A third response was solder joint strength; a "lead pull" test determined the maximum force needed to pull the component lead from the PWB. This paper presents a statistical analysis of the designed experiment. Reflow atmosphere and pad size/stencil aperture have the greatest contribution to the height of lead side wetting. Reflow temperature, palladium thickness, and preconditioning had very little impact on side-wetting height. For lead pull, variance in the data was relatively small and the factors tested had little impact.
Technical Library | 2015-08-13 15:52:40.0
Pad cratering has become more prevalent with the switch to lead free solders and lead free compatible laminates. This mainly is due to the use of higher reflow temperature, stiffer Pb-free solder alloys, and the more brittle Pb-free compatible laminates. However, pad cratering is difficult to detect by monitoring electric resistance since pad cratering initiates before an electrical failure occurs. Several methods have been developed to evaluate laminate materials' resistance to pad cratering. Pad-solder level tests include ball shear, ball pull and pin pull. The detailed methods for ball shear, ball pull, and pin pull testing are documented in an industry standard IPC-9708. Bansal, et al. proposed to use acoustic emission (AE) sensors to detect pad cratering during four-point bend test. Currently there is an industry-working group working on test guidelines for acoustic emission measurement during mechanical testing.
Technical Library | 2019-05-06 23:04:05.0
The temperature and humidity test chamber simulate the temperature and humidity, so there are a lot of things customers shoud notice in the process of use, although there is detailed instruction when purchasing the equipment. But some users just know how the device works and start using it. This is very easy to cause problems in the use of the equipment, so Symor intends to describe the safety details during the use of temperature and humidity chamber. 1. Before the test, determine if the sample contains flammable and explosive substances to avoid combustion or explosion during the test. Of course, also make sure there is no flammable and explosive material around the test equipment, otherwise it may cause fire and other accidents. 2, Do not open the chamber door to operate during the experiment, or the gas in the studio may cause the operator to burn and so on. 3. At the end of the test or at the time of regular cleaning of the test chamber, power off the equipment to avoid electrocution accidents. Also, when cutting off the equipment power, pull the power cord to pull out the plug, otherwise it may lead to a rupture of the power cord and so on. You can contact manufacturers if there are some places you donnot understand, do not dismantle and repair the temperature and humidity test chamber without authorization, otherwise it may lead to more serious problems.
Technical Library | 2014-06-23 14:50:52.0
It was unusual to see chip terminations change colors when tin lead solders were used but with the introduction of lead free reflow soldering and the corresponding increases in reflow temperatures terminations are now changing colors. Two conditions are present when reflow temperatures are increased for lead free solder alloys that leads to discoloration. Reflow temperatures are above the melting point of tin (Sn MP is 232oC). Air temperatures commonly used in forced convection reflow systems are high enough to both melt the tin plating on the termination allowing it to be pulled into the solder joint due to solder joint liquid solder surface tension leaving behind the exposed nickel barrier. Now those metal oxide colors will be visible due to high air temperatures during reflow.
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