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What is SMT stencil?

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Published by Pinsheng Electronics Co., Ltd February 20,2020

 

What is SMT Stencil?

SMT stencil it is a mold used for surface mounting, the hole on SMT stencil is aligned to each SMD, aimed to put solder paste or red glue at the corresponding locations on the empty PCB board.

 

Classification of PCB Stencils

A. According to use:

1. Solder pasting stencil, as the name suggests, it is used to solder pasting, of which the holes correspond to the pads. The PCB board is covered by stencil, solder paste will be transferred onto the board in the solder pasting processing, in which PS needs to control the thickness of solder paste left on the board.
2. Red gum stencil, which is used for pasting red gum, the holes correspond to the blank space between two pads of an SMD. This stencil is used to fix the SMDs in wave soldering processing.

B. According to the manufacturing method:

1. Laser SMT Stencil, cut by laser, which is the most commonly used SMT stencil in the PCB industry. Laser SMT stencil is easy to make, with high precision, easy to use, while affordable, the holes on the SMT stencil has geometric shapes that are good for solder paste printing.

Laser cutting SMT stencil

2. Electropolished stencil (E.P. Stencil), is post-treated by electrochemical means after laser cutting to improve the walls of holes. This stencil is especially good for fine pitch QFP/BGA/CSP.

Electropolished SMT stencil

3. Electroformed stencil (E.F. Stencil), which is good for ultra-fine size devices (such as 0201) or ultra-dense spacing (such as uBGA).
4. Step SMT stencil, due to the difference in the thickness of solder paste required for soldering various components on the same PCB, PS thins the SMT stencil locally to reduce the thickness of solder paste on particular components.

Step SMT stencil

 

Production Steps (for Laser SMT Stencil)

1. Make CAD drawing according to Gerber

Make pcb stencil drawing according to Gerber

2. Framing

SMT stencil framing

3. Laser cutting

Laser cutting

4.QC & packaging

 

PS Electronics made quick and high-quality SMT stencils, note to clean the SMT stencils at any time during use, which can be used for tens of thousands of times.

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