什么是通孔 PCB，为什么它很重要 印刷电路板? PCB 需要通孔或钻孔来连接其各层。 Understanding the standard through-hole sizes used by PCB manufacturers can help you design boards to meet common bit sizes.

Standard through hole size

PCB制造商在钻孔时有自己的一套标准孔尺寸可供选择，但他们通常可以使用任何标准孔尺寸。 一般来说，PCB 制造商可以将 PCB 通孔的直径做得小至 0.15 毫米，而正常尺寸为 0.6 毫米。

PCB通孔尺寸要求

这是对尺寸要求的深入研究。

PCB通孔尺寸

PCB 通孔的尺寸会根据其位置、用途和其他因素而有所不同，这就是为什么每个 PCB 制造商都提供多种 PCB 位尺寸的原因。 Most manufacturers can make holes as small as 0.15 mm or larger holes of 1 mm or larger. 在考虑所需孔的尺寸时，还需要考虑孔周围的环或铜垫，它们会形成。

How do you calculate rings? The ideal ring is equal to the sum of the diameter of the copper pad minus the diameter of the drill hole divided by 2, which gives the rig the best chance of hitting the center of the pad for optimal connectivity.

Standard through hole size

PCB制造中不一定有任何标准的PCB通孔尺寸，因为标准PCB通孔尺寸通常因制造商而异。 然而，许多 PCB 制造商更喜欢使用通用位尺寸，他们可能将其称为标准 PCB 位尺寸。 最常见的尺寸之一是 0.6 毫米，但也常用 0.2 毫米和 0.3 毫米。

Type of PCB through hole

您可以使用每种标准通孔尺寸来创建各种类型的 PCB 通孔，具体取决于 PCB 的层、结构、设计和用途。 三种最常见的 PCB 通孔类型是：

镀通孔

Electroplated through-holes (PTH) are through-holes that run through all layers of a PCB to connect the top and bottom layers. 您应该能够看到从 PCB 的一端到另一端的 PTH。 PTH 可以是电镀的或非电镀的。 非镀通孔不导电，而镀通孔是电镀的，这意味着它们在PCB的所有层都导电。

盲孔

Blind holes connect the outer (top or bottom) layers of the PCB to one or more inner layers, but do not completely drill through the board. Precise drilling of blind holes can be challenging, so they are typically more expensive to manufacture than PTH.

嵌入式

Embedded holes can also increase the cost of PCB because they are difficult to manufacture. The holes are located in the inner layer of the PCB to connect two or more inner layers. 你看不到 PCB 外层的掩埋材料。

需要考虑的事情

创建 PCB 时需要考虑一些事项。 首先，您应该知道PCB设计中的纵横比是什么。 The aspect ratio is the PCB thickness relative to the diameter of the through hole, which determines the reliability of the copper plating on the PCB. The higher the ratio, the more difficult it is to obtain reliable plating, which affects the type of hole and plating method you choose.

嵌入式或盲孔可以更好地为您的 PCB 提供 15:1 的纵横比，而 PTH 可以在 2:1 的低纵横比下很好地工作。 How do you choose the thickness of PCB copper? Usually, through holes in the outer layer (e.g., through holes) require a thicker layer of copper than the buried through holes inside. PCB 使用的电压也会影响铜的厚度。 High voltage applications typically require thicker PCB copper than low voltage applications.

By filling program

Sometimes PCB through-holes need to be filled, for example to reduce the risk of trapping air or increase electrical conductivity. Some common ways to fill through holes include:

穿过帐篷

通孔帐篷在 PCB 通孔上形成阻焊层，而不是用材料填充孔。 这可能是覆盖通孔的快速、简单且经济高效的选择，但帐篷式通孔可能会随着时间的推移重新打开。

通过阻止

通孔堵塞工艺用非导电材料填充孔并用掩模密封。 Through-hole clogging also covers the ring and does not produce a smooth, glossy surface.

通过填充

通孔填充使用树脂来创建永久填充的孔。 通孔填充是一种常见的通孔填充，制造商用导电材料填充通孔，在表面涂上铜，然后修整表面。 This process can route signals to other areas of the PCB.

PCB通孔电镀应用

制造商可能会使用几种不同的技术来应用 PCB 通孔电镀以确保其有效性。 One common method is to use a low viscosity ink that covers the inside of the through-hole to form a conductive layer. Then through the heat curing process to bond the ink.

另一种方法是电镀，其中 PCB 进入电镀槽。 在这个过程中，铜覆盖了每个 PCB 通孔的壁，导致导电材料的厚度均匀。 这种方法往往比上墨过程更耗时、更昂贵，但它也可以形成更可靠的涂层和粘合。

Sequential drilling blind drilling and deep drilling

带有盲孔的 PCBS 可以通过两种方式制造。 这可以通过激光钻孔或称为连续层构造的方法来完成。 Using the sequential construction method, pairs of layers can be drilled and electroplated before bonding is applied. Because they have holes at both ends, electroplating is easy to penetrate for chemical coatings. It also allows blind holes to be designed in such a way that they can pass through multiple layers.

结合适当的键合、钻孔和电镀顺序的能力使得创建多个盲孔结构成为可能。 这完全取决于盲孔是否可以从外层穿过偶数层。

Simultaneous deep drilling or reverse drilling is the process of removing any unused copper drum residue from the through hole. This usually happens when high-speed signals are distorted as they pass through copper tubes between PCB layers. 如果使用信号层导致横向较长，则会出现很多失真。

PCB纵横比定义为板厚与钻孔直径之比。 盲孔需要 1 比 1 或更大的纵横比。

进行深钻孔时，孔的深度是通过设置一对孔来定义的，这些孔指定从板的侧面开始和结束层。 深孔钻头直径按以下公式计算：

背钻尺寸 = 孔/焊盘孔尺寸 + 2 x 设计规则 背钻尺寸过大

PCB overinductance calculator

PCB 通孔电感取决于几个因素，包括通孔尺寸、环尺寸、纵横比和钻孔精度。 您可以找到在线计算器，帮助您根据需要使用的尺寸计算合适的 PCB.