Automatic solder paste printing is to fix the circuit board to be printed on the printing positioning table, and then the left and right scrapers of the printing machine leak the solder paste or red glue to the corresponding pad through the steel mesh. The PCB with uniform missing print is input to the mounter through the transmission table for automatic mounting. The automatic solder paste printing machine is superior in printing speed, printing quality and printing accuracy.

The first thing to pay attention to is the type and hardness of the scraper of the solder paste printing machine.

For the selection of solder paste printing scraper, guangshengde recommends the technical scraper, because its flatness, hardness and thickness are very stable and constant, so as to maintain the better quality of printing.

Secondly, we need to pay attention to the full-automatic solder paste printing scraper.

Scraper is one of the important points for attention in the use of automatic solder paste printing machine. Because the scraper is directly in the printing operation, the distance between the scraper and FPC must be ensured during printing. Generally, the included angle is between 60 and 75. Too large or too small will affect the printing effect.

The third need to pay attention to the speed of automatic solder paste printing.

When the automatic solder paste printer is used for printing operation, the speed should not be too fast, otherwise it is likely that some places will not be printed. On the contrary, if the speed is too slow, the printing effect will be uneven. Generally speaking, it is the best to keep the printing speed within the range of 10-25mm / s, so as to optimize the printing effect.

The fourth thing to pay attention to is the pressure of solder paste printing.

When printing solder paste, it is best to set the pressure to 0.1-0.3kg/cm long. In general, it is best to set it to 0.1-0.3kg/cm length. Too little printing pressure will make the amount of solder paste on FPC insufficient, while too much pressure will make the solder paste too thin, and increase the possibility that the solder paste will pollute the reverse side of the metal leakage plate and the surface of FPC. In this way, the printing effect is relatively uniform, and there will not be too much pressure to make the solder paste print too thin, which also avoids the possibility of side leakage in the printing process.

1、 Classification of scraper of automatic solder paste printing machine:

Common scrapers can be divided into rubber scrapers and metal scrapers according to data. Now most of them use stainless steel metal scrapers; According to the shape, it can be divided into diamond scraper and trailing scraper. Most factories use trailing scraper.

1. The diamond scraper consists of a square with a cross section of about 10 * 10mm and is clamped by a splint to form a 45 ° viewpoint on both sides. This scraper can work in two directions and cross the solder paste strip at the end of each stroke, so only one scraper is needed. However, it is very simple to get dirty. Because the solder paste will run up and its flexibility is not good, it means that the distorted PCB cannot be pasted, which may form a missing printing area, Therefore, the diamond scraper is rarely used now.

2. The trailing scraper is composed of rubber or metal with rectangular section and supported by splint. Two scrapers are required, one in the direction of printing stroke, and there is no need to cross the solder paste strip. Because the solder paste is between the two scrapers, the viewpoint of each stroke can be determined independently. About 40mm scraper is exposed, while the solder paste only goes up 15 ~ 20mm, so this method is cleaner.

In fact, there are many kinds of scrapers. Later generations have done a lot of research on scrapers and made various improved scrapers, such as anti overflow scrapers and energy-saving scrapers.

2、 Effect of scraper of automatic solder paste printing machine:

During printing, the scraper pushes the solder paste to roll in front to make it flow into the template hole, and then scrapes off the remaining solder paste, leaving a solder paste as thick as the template on the PCB pad.