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PCB drilling – drill the holes in PCB manufacturing process


The design of electronic products is from schematic drawing, PCB manufacturing to PCB layout and wiring. This article will comprehensively introduce PCB drilling, which is a very important step in PCB manufacturing process. The purpose of drilling is mainly to drill through holes on the board surface for line connection between layers.

How are holes made in PCB?

In order to mount and solder different electronic components into a PCB, it must be drilled to create holes in it. Otherwise, there will not be any place to mount the required electrical components. It is possible to create holes in a PCB through mechanical means like punching, laser cutting, or drilling and electrochemical means like chemical milling.

A series of holes will be created on the board based on the contour of the board and how it is designed. These holes must be filled afterward with necessary electrical components.

What is PCB drilling?

PCB drilling is the process that involves creating cavities, slots, and holes in a circuit board. Usually, during the process of PCB drilling, different types of holes are created. Some of these holds include mechanical holes, component holes, micro-holes, blind holes, buried holes, and thru-holes.Since a lot of precision is required, a laser or manual PCB drill is used to carve out holes. It is possible for boards to be also fed manually into a drilling rig.what-is-PCB-drilling

What are the common types of drill holes in PCB?

there are three different drill holes, which also are called via types: Through hole, blind hole and buried hole. More information about these three types, you can get more information in the article on our website.

Blind hole: It refers to connecting the outermost circuit in a PCB with the adjacent inner layer by electroplating holes. Because the opposite side cannot be seen, it is called blind through. At the same time, in order to increase the use of space between PCB circuit layers. That is, the through hole to one surface of the printed circuit board.

Through hole (VIA): It is used to conduct or connect copper foil lines between conductive patterns in different layers of the circuit board. Such as (such as blind hole and buried hole), but the copper plated hole of component guide leg or other reinforcement materials cannot be inserted. Because PCB is formed by stacking and accumulating many copper foil layers, each layer of copper foil will be paved with an insulating layer, so that the copper foil layers cannot communicate with each other, and the signal is connected by via.

Buried hole: a conductive hole that is connected between any circuit layers inside a PCB but is not conductive to the outer layer, that is, does not extend to the surface of the circuit board.

Why PCB drilling is required?

PCB drilling is the most time-consuming and expensive part of manufacturing a circuit board. It must be performed precisely to acquire the desired results. PCB drilling is necessary to make and carve holes on the circuit board and these holes are used to mount the required electrical components. Otherwise, an electronic device would not work. Therefore, PCB drilling is performed to create and drill holes into a circuit board so that components can be fixed on it.

How many steps in the PCB drilling process?

There are several steps involved in the PCB drilling process. The standard process involves running the circuit board with its laminated layers through the drilling machine. As the machine is programmed, it will plate the holes inside out. A similar process is utilized for almost all thru-holes. The process, however, changes for vias because it does not require drilling through the board.

Therefore, it is important to note that steps involved in the drilling process vary depending on the type of holes required.The following are the steps in PCB drilling and their functions:

① Feeding: it is mainly used to send the blank board or multilayer board to the drilling area.

② PCB bit preparation: It is mainly used to prepare qualified PCB bits according to the material number of the board to be drilled and the hole diameter and number required by the customer.

③ Drilling: It is mainly used to connect the circuit board up and down and make the installed components work.

④ Inspection: It is mainly used to check whether the boards after drilling meet the customer’s requirements according to the drilling inspection specifications and customer requirements.

⑤ Transfer: It is mainly used to transfer the drilled boards to the next process for processing after being confirmed by drilling AC and IPQC.

What is the material used in PCB drilling?

Considering the fact that quality of drilled holes is more than just a little important, it is necessary to use the right and suitable tools. Typically, tungsten carbide and high-speed steel are utilized as drill materials for composite drilling. It is worth noting that carbide tools tend to provide better tool life during GFRP or glass fiber reinforced polymer machining. Generally, in PCB drilling, cemented carbide drills are utilized.

What is drill size in PCB?

It is important to note that there are different drill sizes in PCB and you can easily find many drill sizes. However, it is recommended that holes must be made at least 0.3 mm wider than the required component. You can find drill sizes ranging from 0.8 mm to 1.5 mm easily and you can even find larger drill sizes. As it has been explained, the required drill size depends on the components you need to install and the holes you must plate on the circuit board.

How is PCB drill size calculated?

The PCB drill size is calculated by determining the size of hole it creates. It is possible to measure the finished hole size by adding 0.00mm/0mil for different non-plated through holes. Meanwhile, for plated through holes, it can be measured through: finished hole size + 0.10mm/4mil.By measuring the hole size, the drill size can be calculated. It can also be determined how large hole the drill will create in the circuit board.

What is used to drill holes in PCB?

In order to drill hols in a PCB, different types of methods and drills are utilized. When it comes to the materials that are used, they tend to vary. However, there are some materials that are used commonly. For instance, tungsten carbide and high-speed steel are used commonly as drill materials for composite drilling. Meanwhile, carbide tools tend to provide better and high tool life. In PCB drilling, cementer carbide drills are used commonly as they offer incredible results.

FAQ about PCB drilling


What is the best PCB drilling tool?

The best PCB drilling tool is definitely a drill press. It plays a critical role in offering and producing precise holes. However, most people even consider using a handheld rotatory drill for drilling holes. Some people even consider using a rotatory drill and a drill press because this set-up enables users to securely clamp a circuit board before holes are mounted easily and precisely.

Can you drill in FR4?

When it comes to PCB drilling, there are several softer materials that require careful drilling such as FR4. Even though it is possible to drill in FR4 PCB, it requires careful drilling. After all, FR4 PCB tends to break out on the bottom. Therefore, it is necessary to use a backer board and a mechanical drill. It helps in ensuring that FR4 PCB does not break and the required holes are created in an effective manner.

What is standard PCB hole size?

Even though there are no fixed hole sizes, there is still a range of standard hole sizes to help and guide people. For instance, the standard size of holes for resistors and ICs is 0.8m. Meanwhile, the hole size is 1.2-1.5 mm for trimmers and terminal blocks. It is generally larger for larger components.

What is a PCB drill bit?

A PCB drill bit is actually a tip that is used in drilling machines for creating holes and removing material. Typically, PCB drill bits come in different shapes and sizes. Depending on the machine and their material, these bits can be used for creating different types of holes in different materials.


Printed circuit boards are critical components of every electronic device. If they are ineffective, your device will simply not run. When we really talk about PCB boards, we cannot overlook the role of PCB drilling. After all, PCB drilling can either make an incredible circuit board or break it.



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