In order to improve the printing quality of solder paste printer, it is not only necessary to control the printing process of solder paste printer, but also very important for the process control of solder paste.

1、 Parameters of scraper of solder paste printing machine

The parameters of the scraper include the material, thickness and width of the scraper, the elasticity of the scraper relative to the tool holder and the angle of the scraper to the template. These parameters affect the distribution of solder paste to varying degrees. The angle of the scraper relative to the formwork θ When it is 60 ° ~ 65 °, the quality of solder paste printing is better.

While printing, the relationship between the opening size and the direction of the scraper should be considered. The traditional printing method of solder paste is that the scraper runs at an angle of 90o along the X or Y direction of the template, which often leads to the different amount of solder paste on the device in different directions of the opening. After experimental verification, when the long direction of the opening is parallel to the direction of the scraper, the thickness of the solder paste scraped is about 60% more than that scraped when they are vertical. Printing with the scraper in the direction of 45 ° can significantly improve the imbalance of solder paste in the direction of different formwork openings, and reduce the damage of the scraper to the formwork openings with fine spacing.

2、 Printing method of solder paste printing machine

The printing method of template can be divided into contact type and non-contact type. Printing with a gap between the template and the printed board is called non-contact printing. When the machine is set, this distance is adjustable, and the general clearance is 0 ~ 1.27mm; The printing method of template printing without printing gap (i.e. zero gap) is called contact printing. The vertical lifting of the template of contact printing can make the printing quality less affected. It is especially suitable for solder paste printing with fine spacing.

Demoulding speed of solder paste printer

The separation speed between printed board and template will also have a great impact on the printing effect. If the time is too long, it is easy to leave solder paste at the bottom of the template. If the time is too long, it is not conducive to the upright of the solder paste and affect its clarity.

3、 Template cleaning of solder paste printing machine

In the process of solder paste printing, the bottom of the template shall be cleaned every 10 plates to eliminate the attachment at the bottom. Anhydrous alcohol is usually used as the cleaning solution.

4、 Special attention should be paid to the process control when using solder paste

1. The solder paste shall be used strictly within the validity period. The solder paste shall be stored in the refrigerator on weekdays. It shall be kept at room temperature for more than 6h before use, and then the cover can be opened for use. The used solder paste shall be stored separately, and the quality shall be determined when reuse;

2. Before production, the operator shall use special equipment to stir the solder paste to make it uniform, and regularly measure the viscosity of the solder paste with a viscosity tester or qualitative;

3. After the first printing board or equipment is printed on duty on that day, the solder paste thickness tester shall be used to measure the solder paste printing thickness. The test points shall be selected at the top, bottom, left, right and middle of the test surface of the printed board, and the values shall be recorded. It is required that the solder paste thickness range from - 10% to + 15% of the template thickness;

4. During the production process, 100% inspection shall be conducted for the printing quality of solder paste, mainly including whether the solder paste pattern is complete, whether the thickness is uniform, and whether there is solder paste sharpening.

The printing of solder paste printing machine is a highly technological process, which involves many process parameters. Improper adjustment of each parameter will have a great impact on the quality of pasted products. If the above four points are well controlled, the printing quality of solder paste printing machine will be effectively improved.