PCB design CAD systems have many layers built into them that can be used for board information other than the silkscreen, and we will take a look at that next. The silkscreen conveys a lot of information about the circuit board, but it isn’t the only method of communicating board information. This can include the name, part number, and revision of the circuit board, as well as corporate contact information, copyrights, and manufacturing markings. Silkscreen markings are also used for marking non-component information as well. Component identification is also important for boards that are assembled using automated systems for test and debug purposes, as well as automated optical inspection (AOI), and manual inspection. This doesn’t lessen the need for component identification though, as these are still important for prototype, NPI, and limited-run boards that will require manual assembly. It is common therefore to see reference designators abbreviated as a sequence of numbers, and often the outlines themselves are completely omitted. As the component density on printed circuit boards continues to increase, however, there is less space for silkscreen information to be printed. Silkscreen is also used for component polarity and pin 1 indicators. The silkscreen’s primary purpose is to mark the position of the components on the board with an outline, and the part’s unique reference designator. Acrylic ink is applied using an inkjet printer working directly from the data in the CAD design manufacturing files. Just like the application of solder mask to a circuit board, a liquid photo-imageable epoxy is applied, exposed under UV light, and then developed and cured.ĭirect legend printing: This is the most accurate method of printing silkscreen markings on a circuit board, but it is also the most expensive. Liquid photo imaging (LPI): For ink images that are smaller in size and require greater accuracy, the LPI process will be used instead. The limitation in this process is the width of the ink which can’t get any smaller than 0.007 inches. Manual silkscreen printing: This is the standard method of printing markings on a PCB by using a stencil as a template and pushing a non-conductive ink through a polyester screen onto the board. Below you’ll find all the silkscreen processes available and why you may or may not want to use them: And while it is true that a manual silkscreen process is still used to create markings on a PCB, there are two other processes available as well. Printing the silkscreen onto the board is one of the last steps to be completed during printed circuit board fabrication. This is why the CAD tool layers devoted to these markings are referred to as the silkscreen layers. Silkscreen is not only a type of printing process used to apply identification markings on a printed circuit board, but it is also the generic term used to describe the ink markings themselves. PCB Silkscreen: What It Is and What It’s Used For Let’s take a closer look at the PCB silkscreen process and some recommendations for silkscreen design best practices. How the images are rendered on the circuit board depends on the method used by the PCB designer in managing silkscreen layers and PCB stackup information in their CAD system. What is less known is that a variation of this process has been used for years to create images and markings on printed circuit boards. Today, most people are familiar with silkscreen printing being used to create their favorite images and patterns on T-shirts. This resulted in it being given the name that it is known by today. Around the 15th century, silkscreen printing found its way to the West, where the original material used for the screen was silk. ![]() Stencils have been used throughout history to decorate the tombs of pharaohs and produce various religious images. Silkscreen printing with stencils is an art form that has been around for a long time. How constraint management can help with the design of your PCB silkscreenĪdjusting silkscreen on your PCB - moving text to open space and changing the orientation for better readability. ![]() Managing the silkscreen and other informational layers within the CAD database ![]() The origins of the PCB silkscreen and what it is used for
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