The Importance of PCB Stencil in the PCB Soldering Process

The PCB printing stage is an important part of the PCB soldering process. Furthermore, this is the most challenging step as even minor errors can seriously affect the functionality of the final product. Most printing phase errors are caused by the mounting of solder joints on the board.

PCB stencil printing is the best solution to avoid these mistakes. With PCB stencil printing you can truly automate solder joint installation. This saves you time and eliminates human error that occurs during the manual installation of solder joints. In the manufacturing of soldering electronic components, PCB stencil is a seemingly insignificant but crucial tool. It ensures welding accuracy and consistency, providing reliable support for the manufacturing of modern electronic equipment. This article discusses everything you should know about solder-paste PCB stencil printing.

What is a PCB stencil?

PCB steel mesh is a thin steel plate covered with many pad holes. You can use it to apply exactly the right amount of solder paste on your PCB. Your PCB is ready for surface mount device (SMD) repair by applying solder paste to the stenciled surface. After the stencil is removed, solder paste deposits remain on the surface and form holes in the stencil.

The positions of these holes correspond to the pad positions of the chip components on the PCB board. They play a key role in the patch processing process. They are used to accurately print solder paste onto the pads of the PCB, laying the foundation for subsequent component mounting and welding.

There are 2 main types of stencils: framed stencils and frameless stencils. Frameless templates are relatively low-cost and suitable for making samples, so they are not suitable for large-volume PCB printing. The stencil material significantly affects its ability to spread solder paste through the holes. Nonetheless, you can improve the solder paste ejection capabilities of the stencil by coating it.

The role of PCB stencil

The function of the PCB stencil is to provide support for brushing solder paste on the pads of these components before soldering the chip components.

The importance of steel mesh in SMT patch processing is self-evident. A high-quality steel mesh can ensure uniform application and precise positioning of solder paste, thereby improving the welding quality and reliability of chip components. On the contrary, if the stencil is not made accurately or used improperly, it may lead to problems such as uneven application of solder paste and incorrect component placement. In serious cases, it may even cause faults such as poor welding or short circuits.

The thickness of PCB stencil

The thickness of the stencil is the thickness of the solder paste printed on the surface of the PCB pad. It should be determined based on the distribution density of PCB components, component packaging form and size, and the distance between pins (or BGA solder balls). Commonly used stencil thicknesses There are 0.1mm, 0.12mm, 0.13mm, 0.15mm, 0.18mm, etc. The front 0.1 mm-0.15 mm is commonly used for the production of solder paste stencils, and the back 0.18mm is commonly used for the production of red glue stencils. We usually use stainless steel sheets with a thickness of 0.1~0.15mm to make steel mesh. For high density, the resistance and capacitance of 0201 can be selected between 0.08mm and 0.1mm.

Conclusion

As mentioned above, PCB stencil plays a vital role in PCB patching. They determine the final performance of the product, so it is very necessary to choose a high-quality pcb stencil. Please feel free to contact us for any PCB stencil products and services. We specialize in PCB manufacturing and advanced equipment that ensures high-quality PCBs and services.