The first process: the operator loads the PCB into the turnover frame, and then loads the turnover frame into the upper plate case; the automatic upper plate machine feeds the PCB light plate to be printed with the solder paste into the printing machine through the track.

The second process: the printing machine has installed the corresponding product steel mesh, the upper solder paste, and the PCB is applied with pressure through the steel mesh to uniformly print the solder paste. The printing machine automatically operates the printed PCB board, and then visually inspects the solder paste PCB for any missing marks, offsets, tin, flash, etc.

The third process: printing the solder paste PCB through the docking line into the high-speed and general-purpose placement machine for mounting components. The operator must look at the PCBA from the device for 15 minutes. In the production process, when the buzzer sounds, the alarm light is on and the abnormality must be handled immediately.

The fourth process: the key process is to reflow soldering, the solder paste on the circuit board is converted into tin point by infrared hot air to achieve the purpose of soldering. (The reference temperature curve of solder paste MULTICONORE and KESTER: a. preheating stage. 25 ° C to 130 ° C, the temperature rise slope is less than 2.5 ° C / sec, time 60 ~ 90 seconds. b. soaking stage. 130 ° C to 183 ° C or so 1.5 minutes to 3 minutes. The middle part should be close to 150±10 °C. The maximum slope is less than 2.5 °C/sec. c. The reflow phase. The time above 183 °C is 60~90 seconds. The peak temperature is 210 °C~220 °C. d. Stage. The cooling slope is required to be 2~4 °C/sec.)

Step 5: The soldered PCBA enters the automatic optical detector AOI for inspection of the appearance quality of the solder. (AOI optical automatic detection equipment is to optically form an image and then process the image and then judge various defects on the PCB. In theory, it can be judged that any human eye can see various defects, (offset, less tin) , short circuit, pollution, missing parts, skew, tombstone, side up, overturned, wrong piece, broken, high, polarity, cold welding, empty welding, overflow glue, tin hole, pin not out, etc.) In the actual use process, there will be false detections and missed inspections, which are affected by the technical conditions of each equipment manufacturer and the proficiency of the equipment users.)

The sixth process: the middle through the dispensing, the board and other auxiliary processes, into the back assembly line for assembly.