Currently, many different types of laser steel mesh used in the electronics industry come from many different suppliers, but not all steel meshes are the same. Due to the requirement that the steel mesh industry can deliver quickly, in many cases. On-time delivery is as important as the performance of a steel mesh.

It is believed that about 50% of the defects on the smt assembly line are caused by the printing process. SMT steel mesh has become a commodity. Many steel mesh suppliers are selling it. Sometimes, it is only purchased at its price. It does not pay attention to quality and experienced technical support. Does it look unusual? At the same time, we also It has been seen that the requirements for stencil performance are becoming more and more challenging due to the continued miniaturization of packages and components. Currently. Many different types of stencils used in the electronics industry come from many different suppliers, but not all stencils are the same. Due to the requirement for the stencil industry to deliver quickly, in many cases, on-time delivery is as important as the performance of stencils.

There are many types of stencils, including stencils made directly from laser cutting technology on stainless steel, to high-end all-nickel electroformed stencils, and there are many types of stencils and variations between the two stencils. The choice of steel mesh depends on the specific technical requirements of the application. This depends on the following variables:

The minimum component spacing to be printed;

The type of component placed on the board;

The area ratio of the smallest component is calculated;

Currently, laser cut steel mesh is a common steel mesh. The technology behind laser cutting equipment continues to improve, and the improvement in core materials is extremely fast, which greatly expands the ability of lasers to directly cut steel mesh. As a result, they are becoming more and more popular, and the number of laser direct-cutting steel mesh suppliers has increased. Each piece of stencil performs differently in printing, and the results of printing vary greatly. The cumulative use time and performance of the laser equipment used to cut the stencil may affect the printing process and ultimately affect the area ratio (AR) of the stencil. The area ratio has become an important factor in distinguishing what type of stencil is used. The area ratio is the mesh area of the mesh hole divided by the area of the pad under the mesh. The smaller the area ratio, the more challenging the solder paste release, so the mesh must be perfectly aligned and the hole walls must be smoother. In the past, it was considered that the area ratio was very small from 0.5 to 0.6, and it is now expected that the area ratio will be reduced to 0.42.

For smaller area ratios, one way to improve the performance of a PCB stencil in laser cutting is to electrolytically polish, stencil, or produce 100% nickel mesh by stepwise electroforming. Electropolishing and nickel plating make the sidewalls of the mesh surface formed by the laser cutting process smooth, but these processes require more time, and the adverse effect is to delay the delivery time of the steel mesh. On the other hand, by laser cutting a piece of 100% nickel, you can get the smallest laser cut area ratio, but the delivery time is the same as the delivery time of the laser directly cut stencil. Some of the better performing laser-cut stencils have an area ratio of 0.48 to 0.50. Also, laser-cut nickel plates, or laser-cut stencils that have been processed after cutting, can vary greatly from supplier to supplier.

Speaking of the area ratio, for all current applications, even if the area ratio is 0.48, it is not small enough. In these cases, fully electroformed steel mesh is the next step in the manufacture of steel mesh. A 100% nickel steel mesh is formed by electroforming, and the mesh is formed simultaneously in this process. The hole wall obtained by this method is smoother. As with other types of stencils, the electroforming capabilities and stencil quality of this method are also different. The best electroformed steel mesh with an area ratio of 0.42 has the best performance, while other methods of manufacturing a steel mesh with an area ratio of 0.49 may not print well.

As electronic devices continue to be miniaturized, for stencil manufacturers, their more important thing now is to increase investment and improve testing capabilities. Obviously, for steel mesh, there are now many options. It is a topic in itself to know what kind of steel mesh is needed for what kind of application, and to have a deep understanding of it, while at the same time trying to minimize the cost of the steel mesh and keep it fast.