PCB News - What is the process flow of PCB board placement?

What is the process flow of PCB board placement?
Any PCB board placement company will combine all employees to hold a preliminary work conference before processing and production. Only by uploading and issuing can ensure the stability and speed of the operation process. At present, in order to continue to actively play the role of PCB board, improve the quality of PCB board placement and corporate culture, every process from construction, installation to commissioning is very strict, and only in this way can related problems existing in the operation be addressed. Dispose of them and give play to their versatility to achieve innovation and development.

PCB board

With the vigorous development of the social economy, a variety of electronic devices continue to be new, and there are devices that cannot be separated from electronic components, so what is the installation operation of the PCB board? First of all, we have to judge what the structure of the circuit board looks like, especially for wires and tubes with a relatively large structural rigidity, which is more troublesome to operate. Therefore, the staff should avoid tension, and tension cannot be carried out. Next, the technicians of Dongguan Boyuan Electronics Co., Ltd. will introduce the process flow of PCB board placement:

The first step: apply solder paste. What is the purpose of this? During operation, it is necessary to evenly place an appropriate amount of solder paste on the PCB pads to ensure that the SMD components and the corresponding pads of the PCB achieve good electrical connection and have sufficient mechanical strength during reflow soldering. Speaking of this, it is necessary to popularize science about what is solder paste? Solder paste is a paste with a certain viscosity and good touch characteristics, which is a mixture of alloy powder, paste flux and some additives. At room temperature, because the solder paste has a certain viscosity, the electronic components can be pasted on the PCB pads. When the inclination angle is not too large, and there is no external force collision, the general components will not move. When the paste is heated to a certain temperature, the alloy powder in the solder paste melts and then flows, and the liquid solder infiltrates the solder ends of the components and the PCB pads. After cooling, the solder ends and the pads of the components are interconnected by the solder to form electrical and mechanical Connected solder joints.

PCB patch

But how does the solder paste come out? Solder paste is applied to the pads by special equipment. The equipment includes fully automatic printers, semi-automatic printers, manual printing stations, and semi-automatic solder paste dispensers.

The second step is to mount components on the PCB board. This process is to accurately mount the chip components to the corresponding position on the PCB surface where the solder paste or patch glue is printed with a placement machine or manually. There are two mounting methods, Boyuan Electronics tells you the comparison is as follows:

1. Machine placement. It is suitable for large batches and tight supply cycle. Advantages: suitable for mass production. Disadvantages: complicated working procedures and large investment.

2. Manual placement. Suitable for small and medium batch production and product development. Advantages: easy operation and low cost. Disadvantages: production efficiency depends on the proficiency of operators. And the main tools for manual placement are vacuum suction pen, tweezers, IC suction and placement aligner, low-power stereo microscope or magnifying glass, etc.

PCB board

The third step: PCB board patch reflow soldering. It is to remelt the solder paste pre-distributed on the printed board pad to realize the soft soldering of the mechanical and electrical connection between the solder end of the surface mount component or the pin and the printed board pad. Analyze the principle of reflow soldering from the SMT patch temperature characteristic curve. First, when the PCB enters the preheating temperature zone of 140 degree Celsius～160 degree Celsius, the solvent and gas in the solder paste evaporate. At the same time, the flux in the solder paste wets the pads, the solder ends and pins of the components, and the solder paste softens, It collapses and covers the pad, isolating the pad and component pins from oxygen.
Every step of the process flow of PCBA board placement is extremely important, and there can be no errors in every link. Only in this way can the entire placement work be ensured in an orderly manner.