In the process of SMT chip processing, many SMT chip processing manufacturers often encounter headache phenomena such as more tin beads, IC with tin, less tin, part drop, false soldering, red glue overflow after reflow soldering. In fact, this is not only related to the reflow soldering process, but also related to the printing process of solder paste printing machine.

1、 Image positioning part of solder paste printer

The image positioning of solder paste printer depends on the positioning algorithm, which is also one of the core algorithms of automatic visual solder paste printer. With the increasing production efficiency of PCB, the electronic components on the board are becoming smaller and smaller, which also puts forward higher requirements for positioning accuracy and speed. At present, the positioning algorithms of most automatic vision solder paste printers in the market are based on image gray and realized by autocorrelation matching. For the copper clad plate with good surface uniformity, the gray algorithm can well complete the function of automatic positioning. However, the emergence of more and more tinplate, gold-plated plate and flexible PCB brings great challenges to gray-scale positioning. Due to tin plating and gold plating, the surface uniformity of the plate is not very good and the reflection rate is high, which makes the difference of the imaging brightness of the mark point on the PCB board large, and increases the false detection rate and missed detection rate of gray positioning. Due to the poor flatness of the surface of the flexible board, the imaging of mark points on the PCB will also have the problem of large brightness difference, and the size and shape of mark points will change. These problems are difficult to overcome based on the gray-scale positioning algorithm. The location algorithm based on geometry can well adapt to these problems.

Because the commercial geometric positioning tools in the market are relatively expensive, usually about 10000 yuan. Considering the cost factor, most automatic visual solder paste printers use relatively cheap traditional gray-scale positioning tools. Zhichi solder paste printing machine has adopted geometry based positioning tools on all models. Mark can improve the market positioning of the existing tinplate, which can reflect the improvement of the existing tinplate type.

2、 Demoulding mode of steel mesh of solder paste printing machine

The demoulding of solder paste printing machine directly affects the printing effect. Generally, there are two demoulding methods for automatic visual solder paste printing machine

1. "Lift the scraper first and then demould", which is widely used, mainly simple PCB boards;

2. "Demoulding first and then scraper", using thinner PCB board, etc;

From the perspective of use, high speed and stability are the fundamental requirements of solder paste printing machine. The mark point recognition of solder paste printing machine is the primary factor of the machine. If the mark point recognition is poor, mark point recognition often occurs, but manual intervention affects the production, and corresponding operators need to be added to improve the use cost.

3、 Steel mesh cleaning of solder paste printing machine

All solder paste printing machines are dry cleaning, wet cleaning and vacuum cleaning. With the development of SMT, the gap is small and the speed is fast. Many pull points and even tin on PCB are closely related to cleaning! The quality of automatic cleaning of solder paste printing machine is directly related to the quality of products. The improvement of cleaning function can realize speed, that is, high efficiency of production. The cleaning of domestic solder paste printing machine has been greatly improved. Independent cleaning mechanism and brand-new cleaning concept, including the vacuum adsorption system of powerful exhaust fan, more uniform alcohol injection system and more efficient cleaning method, can realize the benign and sustainable printing of finepitch.

In addition to the problem of the solder paste printer itself, the operator is also the key to the quality. Some details during the operation of the solder paste printer also determine the quality of the finished SMT circuit board. Therefore, the early training of operators is very important.