Technical Library | 2017-12-27 22:52:43.0
To compensate for the insufficiency and instability of solder paste dispensing and printing that are used in the SMT production process, a noncontact solder paste jetting system driven by a piezoelectric stack based on the principle of the nozzle-needle-system is introduced in this paper, in which a miniscule gap exists between the nozzle and needle during the jetting process.
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 | 2021-09-29 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 | 2019-07-02 23:02:05.0
The introduction of lead-free solders resulted in a selection of different chemistries for solder pastes. The higher melting points of lead-free alloys required thermal heat resistant rosin systems and activators that are active at elevated temperatures. As a result, more frequent maintenance of the filtration systems is required and machine downtime is increased.Last year a different method of cleaning reflow ovens was introduced. Instead of cooling down the process gasses to condensate the residues, a catalyst was used to maintain the clean oven. Catalytic thermal oxidation of residues in the nitrogen atmosphere resulted in cleaner heating zones. The residues were transformed into carbon dioxide. This remaining small amount of char was collected in the catalyst. In air ovens the catalyst was not seen as a beneficial option because the air extracted out of the oven was immediately exhausted into the environment. When a catalyst is used in an air environment there is not only the carbon dioxide residues, but also water. When a catalyst is used in an air reflow oven the question is where the water is going to. Will it condensate in the process part of the oven or is the gas temperature high enough to keep it out of the process area? A major benefit of using a catalyst to clean the air before it is exhausted into the environment is that the air pollution is reduced dramatically. This will make environmental engineers happy and result in less pollution of our nature. Apart from this, the exhaust tubes remain clean which reduces the maintenance of air ovens.This paper will give more detailed information of catalyst systems during development and performance in production lines.
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