smt processing common printing shortcomings and solutions Solder paste printing is a very messy skills, both affected by the data, together with the equipment and parameters have a direct link, after the printing process in all aspects of the control can be said Is the details of the resolution victory or defeat, to avoid the shortcomings often appear in print, the following brief analysis of the solder paste printing occurs when the most common shortcomings and the corresponding solution or solution.

First, the solder paste is too thin. Reasons:

1, the template is too thin;

2, scraper pressure is too large;

3, poor solder paste mobility. Avoid or solution: Select the appropriate thickness of the template; select the appropriate particle size and viscosity of solder paste; drop scraper pressure.

Second, tip. Tip is printed solder paste on the pad, the reason may be scraper gap or paste viscosity too much. Avoid or solution: Longhua SMT chip processing properly adjust the small blade gap or select the appropriate viscosity of the solder paste.

Third, after printing, the thickness of solder paste on the pad is not common, causes:

1, the template is not parallel with the PCB;

2, uneven paste mixing, making the particle size is not common.

To avoid or solve the problem: adjust the relative orientation of the template and PCB; pre-press mix solder paste.

Fourth, fall. After printing, solder paste to the two ends of the paddle fall. Reason:

1, scraper pressure is too large;

2, PCB positioning is not strong;

3, solder paste viscosity or metal content is too low.

Avoidance or solution: adjust pressure; fix PCB from scratch; pick solder paste of suitable viscosity.

Fifth, the thickness is not the same. Margins and appearance of burrs, the reason may occur is the viscosity of the solder paste is low, rough template hole wall. Avoid or workaround: Pick a slightly higher viscosity solder paste; check the quality of the openings in the template before printing.

Six, print is not complete. Incomplete printing means that some solder pads are not printed on the pads. The reason may occur is:

1, hole clogging or some solder paste sticking at the bottom of the template;

2, the viscosity of solder paste is too small;

3, solder paste in a larger scale of metal powder particles;

4, scraper wear.