2-5 Instructions for using solder paste products

2-5-1 Management of storage and retrieval of solder paste

1) Solder paste should be refrigerated at 0-10℃ (ideally for 4-8 hours), and the temperature should not fall below 0℃. It takes at least 3 hours for the solder paste to return to room temperature after being taken out of the refrigerator.

Avoid crystallization.

Prevent caking.

After warming up, both used and unused solder paste can recover their original properties (refer to the storage life of solder paste)

2) Stir the solder paste evenly before use.

The automatic mixer takes about 5 minutes.

It takes about 10 minutes to complete manually.

3) At any time during use, ensure that only one bottle of solder paste is opened.

Ensure that fresh solder paste is used at all times during production to reduce the negative impact on the environment. For opened solder paste, tightly close both the inner and outer lids when not in use.

Prevent the solder paste from drying out or oxidizing, thereby extending its service life.

4) Adopt the "first-in, first-out" principle when using solder paste.

The solder paste has always been in its optimal performance state.

5) Ensure continuous rolling during solder paste printing, with the height of the solder paste approximately equal to 1/2 to 3/4 of the height of the metal squeegee during rolling.

Conduct preliminary monitoring of the viscosity of the solder paste.

Smooth rolling can ensure better leakage of solder paste into the openings of the steel mesh, resulting in more exquisite graphics.

6) To ensure the optimal soldering quality of the solder paste, the PCB printed with solder paste should be moved to the next process as soon as possible (within 1 hour).

Prevent the solder paste from drying out, experiencing viscosity changes, and maintain its tackiness.

7) When the solder paste is not used for more than 1 hour, to prevent it from drying out, do not leave the solder paste on the screen printing plate.

To prevent screen blockage.

Prevent the solder paste from drying out and unnecessary screen blockage.

8) When removing the solder paste from the screen, please use another empty bottle to collect it.

It can prevent the old solder paste from affecting the new one.

Store the used solder paste according to the storage conditions for solder paste.

When using old solder paste, mix 1/4 of the old solder paste with 3/4 of new solder paste evenly before use, which can maintain the performance of the new solder paste in the old one.

2-5-2 Printing parameters

1) Squeegee speed: Generally, it ranges from 10 to 150mm/s. Too fast a speed can cause the squeegee to slide and miss printings, while too slow a speed can result in uneven edges of the solder paste prints and contamination of the substrate surface.

2) Blade angle: When within the range of 60-90 degrees, optimal printing efficiency and transferability can be achieved through appropriate printing pressure.

3) Printing pressure: The general printing pressure is set at 0.1-0.3 kg/cm2. Too little pressure results in insufficient solder paste transfer, while too much pressure makes the printed solder paste too thin, increasing the likelihood of solder paste contamination and leakage onto the reverse side of the screen and the substrate. Usually, the pressure should be gradually adjusted from low to high, ensuring that the solder paste is just scraped clean off the screen surface.

4) Hardness and material of scraper: Hardness, Shore hardness 80-90 degrees; material, stainless steel or rubber.

2-5-3 Safety precautions

Please read the Material Safety Data Sheet before use and take proper personal protective measures.

Be careful when using solder paste to avoid it coming into contact with clothing and skin. If it is accidentally spilled, quickly wipe it off with an alcohol-based solvent.

Do not inhale the steam emitted during reflow soldering.

Wash your hands after welding work and before meals.