Technical Library | 2018-04-27 12:59:29.0
Hot Air and IR are the two main types of rework stations used by OEMs and PCB contract manufacturers today. Both have advantages and disadvantages and choosing the right one for your application requires a careful consideration of a number of factors, including your budget, your working requirements and the capabilities of your staff. In this article, we outline some of the differences between hot air and IR BGA rework stations.
Technical Library | 2019-09-25 04:36:01.0
What is the main function of hot air dry oven? Drying ovens are devices used to remove moisture and other solvents from the items placed inside them through a forced convection process, collecting it elsewhere so that the object becomes dehydrated. A drying oven causes objects to dry out through evaporation. Drying ovens use convection heating,also called air forced, in which the object is heated through air currents. Water from the object escapes into the air, raising the humidity level and causing the semi-solid membranes inside the oven to absorb the water. The end result is that the oven removes water from the object being dried, leaving it dehydrated. Drying ovens contain a system for forcing convection currents to develop, usually either a fan or turbine, which aids in the heating and drying process by ensuring that the hot air circulates,many ovens are equipped with an adjustable ventilation system that allows the user to ensure that the system has an adequate air supply. For details,pls visit our website: https://climatechambers.com/articles&latestnews/what-is-the-main-function-of-hot-air-dry-oven.html
Technical Library | 1999-08-09 11:09:42.0
Organic Solderability Preservatives (OSPs), also known as anti-tarnish, on bare copper printed circuit boards (PCBs) are becoming more prevalent in the electronics industry as the low-cost replacement to Hot Air Solder Leveling (HASL). Introducing the anti-tarnish alternative into the customer sites requires working closely with the coating supplier, assembler, and Original Equipment Manufacturer (OEM) to gain a mutual understanding of respective processing concerns and finished product requirements.
Technical Library | 1999-08-09 11:11:55.0
A great deal of controversy continues to surround the use of Hot Air Solder Leveling (HASL) in the production of printed circuit boards (PCBs). The financial burden, technological limitations and environmental issues surrounding the HASL process continue to grow. This requires an in-depth review by the printed circuit board manufacturing plant, as well as the assembly operation and instrument designers ( OEMs), to determine what alternative surface finishes are appropriate.
Technical Library | 2021-07-06 21:13:36.0
The surface finishes commonly used on printed circuit boards (PCBs) have an effect on solder paste performance in the surface mount process. Some surface finishes are non-planar like hot air solder level (HASL) which can lead to inconsistencies in solder paste printing. Other surface finishes are difficult to wet during reflow like organic solderability preservative (OSP). What is the overall effect of surface finish on solder paste performance? Which solder paste is best for each surface finish? It is the goal of this paper to answer these questions.
Technical Library | 2023-11-14 19:24:08.0
In PCB circuit assemblies the trend is moving to more SMD components with finer pitch connections. The majority of the assemblies still have a small amount of through hole (THT) components. Some of them can't withstand high reflow temperatures, while others are there because of their mechanical robustness. In automotive applications these THT components are also present. Many products for cars, including steering units, radio and navigation, and air compressors also use THT technology to connect board-to-board, PCB's to metal shields or housings out of plastic or even aluminium. This is not a simple 2D plain soldering technology, as it requires handling, efficient thermal heating and handling of heavy (up to 10 kg) parts. Soldering technology becomes more 3D where connections have to be made on different levels. For this technology robots using solder wire fail because of the spattering of the flux in the wires and the long cycle time. In wave soldering using pallets the wave height is limited and pin in paste reflow is only a 2D application with space limitations.
Technical Library | 2021-09-29 13:35:21.0
In PCB circuit assemblies the trend is moving to more SMD components with finer pitch connections. The majority of the assemblies still have a small amount of through hole (THT) components. Some of them can't withstand high reflow temperatures, while others are there because of their mechanical robustness. In automotive applications these THT components are also present. Many products for cars, including steering units, radio and navigation, and air compressors also use THT technology to connect board-to-board, PCB's to metal shields or housings out of plastic or even aluminium. This is not a simple 2D plain soldering technology, as it requires handling, efficient thermal heating and handling of heavy (up to 10 kg) parts. Soldering technology becomes more 3D where connections have to be made on different levels. For this technology robots using solder wire fail because of the spattering of the flux in the wires and the long cycle time. In wave soldering using pallets the wave height is limited and pin in paste reflow is only a 2D application with space limitations. Selective soldering using dedicated plates with nozzles on the solder area is the preferred way to make these connections. All joints can be soldered in one dip resulting in short cycle times. Additional soldering on a small select nozzle can make the system even more flexible. The soldering can only be successful when there is enough thermal heat in the assembly before the solder touches the board. A forced convection preheat is a must for many applications to bring enough heat into the metal and board materials. The challenge in a dip soldering process is to get a sufficient hole fill without bridging and minimize the number of solder balls. A new cover was designed to improve the nitrogen environment. Reducing oxygen levels benefits the wetting, but increases the risk for solder balling. Previous investigations showed that solder balling can be minimized by selecting proper materials for solder resist and flux.
Technical Library | 2021-10-20 18:21:06.0
The solderability of the SAC305 alloy in contact with printed circuit boards (PCB) having different surface finishes was examined using the wetting balance method. The study was performed at a temperature of 260 _C on three types of PCBs covered with (1) hot air solder leveling (HASL LF), (2) electroless nickel immersion gold (ENIG), and (3) organic surface protectant (OSP), organic finish, all on Cu substrates and two types of fluxes (EF2202 and RF800). The results showed that the PCB substrate surface finish has a strong effect on the value of both the wetting time t0 and the contact angle h. The shortest wetting time was noted for the OSP finish (t0 = 0.6 s with EF2202 flux and t0 = 0.98 s with RF800 flux), while the ENIG finish showed the longest wetting time (t0 = 1.36 s with EF2202 flux and t0 = 1.55 s with RF800 flux). The h values calculated from the wetting balance tests were as follows: the lowest h of 45_ was formed on HASL LF (EF2202 flux), the highest h of 63_ was noted on the OSP finish, while on the ENIG finish, it was 58_ (EF2202 flux). After the solderability tests, the interface characterization of cross-sectional samples was performed by means of scanning electron microscopy coupled with energy dispersive spectroscopy.
Technical Library | 2023-03-16 18:51:43.0
Conductive anodic filament (CAF) formation was first reported in 1976.1 This electrochemical failure mode of electronic substrates involves the growth of a copper containing filament subsurface along the epoxy-glass interface, from anode to cathode. Despite the projected lifetime reduction due to CAF, field failures were not identified in the 1980s. Recently, however, field failures of critical equipment have been reported.2 A thorough understanding of the nature of CAF is needed in order to prevent this catastrophic failure from affecting electronic assemblies in the future. Such an understanding requires a comprehensive evaluation of the factors that enhance CAF formation. These factors can be grouped into two types: (1) internal variables and (2) external influences. Internal variables include the composition of the circuit board material, and the conductor metallization and configuration (i.e. via to via, via to surface conductor or surface conductors to surface conductors). External influences can be due to (1) production and (2) storage and use. During production, the flux or hot air solder leveling (HASL) fluid choice, number and severity of temperature cycles, and the method of cleaning may influence CAF resistance. During storage and use, the principal concern is moisture uptake resulting from the ambient humidity. This paper will report on the relationship between these various factors and the formation of CAF. Specifically, we will explore the influences of printed wiring board (PWB) substrate choice as well as the influence of the soldering flux and HASL fluid choices. Due to the ever-increasing circuit density of electronic assemblies, CAF field failures are expected to increase unless careful attention is focused on material and processing choices.
Technical Library | 1999-04-29 15:39:03.0
The paper describes the effects of a debridging knife on inerted soldering environments in an Electrovert Econopak wave solder machine. It reviews experiments to improve the purity of the soldering environment and results of the tests.
