Solder pastePrinting isSMTThe first step of surface mount technology (SMT) processing, its quality will directly affect all subsequent processing links. So how should we do it well? The following is the answer from Shenzhen JJY Solder Paste ManufacturerSMTA brief introduction to the precautions for printing solder paste in surface mount technology (SMT) processing

1Solder paste quality

Solder paste is a slurry made by mixing alloy powder with flux and other materials. Whether components can be well soldered onto the solder pad depends crucially on the quality of the solder paste. The main factors influencing it are as followsSMTSolder paste viscosity: the amount of alloy powder, the size of the particles, temperature, the pressure of the scraper, shear rate, flux activity, etc. If the quality of the solder paste is not up to standard, the soldering cannot be achieved well, and the final printing effect will naturally be unsatisfactory.

2Storage of solder paste

Apart from quality, the storage of solder paste is also very important. If the solder paste needs to be recycled after work, it is essential to pay attention to issues such as temperature and humidity; otherwise, it will cause problemsSMTThe quality of the solder joints has an impact. Excessively high temperatures can reduce the viscosity of solder paste, while excessive humidity may lead to deterioration. Additionally, recycled solder paste and freshly prepared solder paste should be stored separately.

3Steel mesh formwork

The steel mesh is printed with solder pastePCBAThe quality of the steel mesh on the pads of the plate is directly affectedSMTThe printing quality of solder paste must be confirmed before processing, such as the thickness of the steel mesh and the opening size, to ensure the printing quality of the solder paste.

PCBAThe spacing of the components on the board is approximately1.27mm,1.27mmThe components with the above spacing are required by stainless steel plates0.2mmThick ones with narrow spacing are required0.15mm-0.10mmThick, according toPCBThe thickness of the stainless steel plate is determined by the condition of most components.

4Printing equipment

The printing press is used to print solder paste ontoPCBThe equipment on the sample is the one that has the greatest impact on the process and quality. Printing machines are mainly divided into manual printing machines, semi-automatic printing machines and fully automatic printing machines. These printing machines have various features and functions. Different printing machines are used according to different needs to achieve the best quality.

5Printing method

The printing methods of solder paste can be divided into contact and non-contact printing.SMTPrinting where there is a gap between the processing screen and the printed circuit board is called non-contact printing. When setting up the machine, this distance is adjustable, and the general gap is0-1.27mm; The printing method of solder paste without printing gaps is called contact printing. The vertical lifting of the screen plate in contact printing can minimize the impact on printing quality, and it is particularly suitable for fine-pitch solder paste printing.

6Printing speed

A fast scraper speed is beneficial for the rebound of the screen plate, but at the same time it will hinder the transfer of solder paste to the solder pads of the printed circuit board. Meanwhile, a speed that is too slow will cause poor resolution of the solder paste printed on the solder pads. On the other handSMTThe speed of the scraper in surface mount technology (SMT) processing has a significant relationship with the viscosity of the solder paste. The slower the scraper speed, the greater the viscosity of the solder paste. Similarly, the faster the scraper speed is, the lower the viscosity of the solder paste will be.

Shenzhen JJY Industrial Technology Co., Ltd. is a professional manufacturerSMTManufacturers of solder paste products such as solder paste, syringe solder paste, lead-free solder wire, wave soldering bar, and automatic soldering wire.