How to Improve SMT Assembly Yields Through Stencil Designs

How to Improve SMT Assembly Yields Through Stencil Designs

 

With the global electronics market expected to exceed $3.5 trillion in 2022 at a 10.3% compound annual growth rate, it's clear that the tech industry is booming. To compete in this growing industry, it's likely that your manufacturing facility is looking to increase SMT assembly yields. You can do this using accurate and detailed stencil designs that allow you to evenly lay parts on your PCBs. Read on to learn how stencils can take your productivity to the next level.

 

The Basics of PCB Assembly and Stencils

Printed circuit board (PCB) assembly has gained popularity in recent years. This is because PCBs have a wide variety of applications, including consumer electronics, automotive components, security equipment, safety-related devices, medical devices, industrial equipment, and LED lighting.

 

As PCBs become more common, manufacturing methods must improve to increase assembly yield. Currently, most surface mount technology (SMT) operations fall under a hybrid assembly model that combines new technologies with old methods. However, cutting-edge stencil designs that eliminate these old methods can greatly enhance yields. A study examining 1,000 different SMT assemblies over four years proved that stencil designs have a significant impact on assembly yields. While a 100 percent yield can never be guaranteed, top-notch stencil designs can help you optimize your productivity.

 

PCB Stencil Design

PCB stencils are cutting-edge technology, but they also are very simple. They're made from a sheet of stainless steel in which openings—which can be almost microscopic—are made with a precision laser-cutting machine. This makes it easy for the PCB manufacturer to lay circuit board parts down with 100% accuracy. Because many circuit board parts are incredibly small (some nearly invisible to the naked eye), accurate stencil design is critical for the assembly process.

 

It's important to note that PCB stencil designs vary widely because circuit boards are not identical across industries and applications. A computer PCB will not look like one needed for aerospace applications. Your stencil design needs to fit your specific application with precise measurements and positions for necessary components.

 

Stencils and the PCB Manufacturing Process

SMT stencils are used to print solder paste onto a PCB. The soldering process lays components onto the PCB base more quickly and efficiently when stencils are used correctly. This leads to a more direct and accurate assembly that increases yields. After laying a stencil onto a base, PCB manufacturers use precise machinery to lay components onto the board so they’re attached securely and can function as designed.

 

Stencils also help manufacturers achieve uniform PCB production. Most manufacturing facilities assemble hundreds (or more) of the same circuit boards. Without well-designed stencils, achieving a consistent product is impossible, but good stencils make it easy.

 

How to Optimize Stencil Design

To get the most out of your stencil design, it's important to choose the right stencil type and material. The experts at MicroScreen can help you optimize your stencils so they meet your exact needs and provide top-notch print performance for your PCB production process.

 

We offer several types of stencils that can be customized to your specifications:

 

  • Standard-cast frames in many shapes, varieties, and sizes
  • Tubular frames in a wide range of sizes
  • Large-format frames for large PCBs (such as LED lighting, some automotive applications, etc.)
  • Space-saving frames that occupy half the floor space of a standard frame
  • Frameless stencils that save storage space and eliminate the need for frame recycling

 

There are also 3 materials to choose from:

 

  • Stainless steel
  • Datum tension (comprised of a finer grain structure ideal for very small stencils)
  • PhD for flat stencils with top-notch paste release uniformity

 

Regardless of the option you choose, you can get the most out of your stencil with customization and individualized production methods. We can create stencils from your existing files and data so that we can meet even hyper specific requests.

 

How Does Stencil Design Increase SMT Assembly Yields?

Stencil printing is one of the most important steps in assembling electronics. This makes sense when you consider that PCBs are the primary factor in whether electronics operate correctly. As a result, SMT assembly yield hinges on stencil design.

 

In fact, process engineers estimate that around 70% of SMT defects are the result of solder paste printing problems. When you print custom stencils to match your PCB process's precise needs, you can dramatically decrease errors in your final products. This lets you avoid wasting materials and makes your operation more eco-friendly and energy efficient. You also won't waste time assembling and testing PCBs that can’t go to market.

 

Increase Your PCB Manufacturing Efficiency

Precise electronics manufacturing can be a challenge, but the right stencils make it easier to create accurate, high quality circuit boards. MicroScreen is committed to providing well-made SMT stencils that are tailored to our customers’ exact specifications. We offer free evaluations for stencils and superior printing quality with top nanocoating technologies. Learn more about optimizing your SMT production process on our blog.