6/17/2023 0 Comments Diptrace tented viasVia tenting creates a solder mask over the PCB via rather than filling the hole with material. Some common ways to fill vias include: Via Tenting It’s sometimes necessary to fill PCB vias, such as lowering the risk of trapping air or increasing conductivity. High-voltage applications usually need thicker PCB copper than low-voltage applications. The voltages used with your PCB will also influence copper thickness. How do you choose the thickness of PCB copper? Generally, vias in outer layers – like through-holes – need thicker copper layers than internal buried vias. The higher the ratio, the more difficult it will be to get a reliable plating, which can influence the type of via and plating method you choose.Ī buried or blind via might serve your PCB better with a high aspect ratio of 15:1, while PTH can work well with a low aspect ratio, like 2:1. Aspect ratio is the thickness of the PCB in relation to the via’s drilled hole diameter, and it determines the reliability of copper plating on a PCB. First, you should learn what is aspect ratio in PCB design. ![]() There are a few things to consider during the process of creating your PCB. You cannot see a buried via the outer layers of the PCB. This type of via sits within the inner layers of a PCB to connect two or more internal layers. Buried ViaĪ buried via can also increase the cost of a PCB because of its difficulty to create. Blind vias can be challenging to drill with precision, so they usually cost considerably more to make than a PTH. Blind ViaĪ blind via connects an outer layer – either the top or bottom – of a PCB to one or more inner layers, but it does not get drilled completely through the board. A non-plated through-hole has no conductivity, whereas a plated through-hole has plating, which means it’s conductive through all layers of the PCB. A PTH can be either plated or non-plated. You should be able to see through a PTH from one end of the PCB to the other. Plating through hole (PTH) is a via that travels through all layers of the PCB to connect the top and bottom layers. Three of the most common PCB via types are: Plating Through Hole You can use each standard via size to create various types of PCB vias, depending on the PCB’s layers, construction, design, and purpose. One of the most common sizes is 0.6 mm, but 0.2 mm and 0.3 mm are also commonly used. However, there are commonly used drill sizes that many PCB manufacturers prefer to use, and they may refer to them as standard PCB drill sizes. ![]() ![]() There aren’t necessarily any standard PCB via sizes in PCB manufacturing because PCB standard via sizes tend to vary between manufacturers and PCB fabricators. How do you calculate the annular ring? The ideal annular ring equals the diameter of the copper pad minus the diameter of the drilled hole divided by two, which gives the drill the best chance of hitting the center of the pad for optimal connectivity. When considering the size of the hole you need, you also need to consider the annular ring, or the copper pad that surrounds the drilled hole, it will form. Most fabricators can create holes as small as 0.15 mm or larger holes of 1 mm or more. Photo by Bill Bradford Licensed Under CC BY 2.0 PCB Via SizeĪ PCB via size can vary depending on its positioning, purpose, and other factors, which is why each PCB manufacturer offers several PCB drill sizes. Here’s an in-depth look at size requirements. Usually, a PCB fabricator can make PCB via holes as small as 0.15 mm with 0.6 mm a common size. PCB fabricators have their own sets of standard via sizes to choose from when they drill, but they can generally use any standard drill size.
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