SMT stencil is a “squeaky” precision mold. Therefore, when using it, you should pay attention to it.
Precautions for Use
- Handle with care;
- The stencil should be cleaned (wiped) before use to remove the dirt carried during transportation;
- The solder paste or red glue should be stirred evenly to avoid clogging the open holes;
- Adjust the printing pressure to the best: the best pressure is when the squeegee can just scrape off the solder paste (red glue) on the stencil;
- It is better to use board printing when printing;
- After the scraper stroke is completed, if possible, it is best to stop for 2 to 3 seconds before demolding, and the demolding speed should not be too fast;
- Do not hit the stencil with hard objects or sharp knives;
- After the stencil is used up, it should be cleaned in time, returned to the packing box, and placed on a special storage rack.
How to Clean SMT Stencil?
Before, during and after use of SMT Stencil, it must be cleaned(usually cleaned with SMT stencil cleaning machine).
- Before Use: Wiping;
- During Use: Wipe the bottom of the stencil regularly to keepit unmolded smoothly;
- After Use: The stencil should be cleaned in time to get the same good demoulding effect next time.
Cleaning Methods
The stencil cleaning methods generally include wiping and ultrasonic cleaning.
Wipe
Wipe the SMT stencil with a lint-free cloth (or special stencil wipe paper) pre-soaked with detergent to remove the solidified solder paste or glue.
Advantage: convenience, no time limit, and low cost.
Disadvantage: It can not thoroughly clean the stencil, especially the fine pitch stencil.
In addition, some printers have an automatic wipe function, which can be set to wipe the bottom of the stencil automatically after a few times of printing. This process also uses a special stencil to wipe the paper, and the machine will spray cleaning agent on the paper before the action.
Ultrasonic Cleaning
There are two main types of ultrasonic cleaning: immersion type and spray type. Some manufacturers use a semi-automatic ultrasonic cleaning machine to clean the stencil.
The Choice of Cleaning Agent
The ideal stencil cleaning agent must be practical, effective, and safe for people and the environment. At the same time, it must be able to remove the solder paste (glue) on the stencil well. There is a special stencil cleaning agent, but it may wash out the stencil, so you should be cautious when using it. If there is no special requirement, alcohol or deionized water can be used instead of special cleaner for SMT stencil.
