PCB Technical - PCB drilling machines and drilling technology

PCB drilling machine is a specialized machine for drilling holes in printed circuit boards (PCBs). Such machines are capable of performing drilling tasks precisely according to a preset program to ensure electrical connections between components and wires on the circuit board.

Introduction to drilling machine and drilling technology

Decades ago, PCB drilling was done with a simple drilling machine. The drilling operator must manually move the panel to adjust and correct the x and y coordinates and drag the lever to drill, which is time-consuming. With the advancement of technology, it has become a constant event in the electronics market, and new drilling techniques have been introduced. Now, PCB is enough to have more than 10,000 holes of different sizes. Let us learn more about PCB layout and drilling operations in PCB manufacturing.

drilling

When a hole is usually drilled on the bottom of the board to connect the board layers thermally and electrically, it is called drilling on a circuit board. These holes when connecting the circuit board layers are called vias. The main purpose of drilling operations in the PCB manufacturing process is to insert through-hole component leads or connect board layers to form a smooth circuit on the PCB. From the beginning, this became a key part of the project, including determining the PCB layout, the materials to be used, the method of manufacturing the PCB, and the type of vias required to connect the layers of the circuit board. Taking a wrong step may prove to be a costly affair, because a tear or damage on the trace may cause the display to fail, and eventually the materials and defects in the batch will be used more.

Drilling machine and drilling technology

Over the years, through technological innovation, the drilling process has become simple. Now PCB drilling can be done with small diameter drills, automatic drilling machines, CNC drilling machines or many other effective drilling machines, suitable for PCB manufacturing of many types of circuit boards.

The automatic drilling machine can drill holes in the circuit board by controlling the drilling operation with a computer. When multiple holes of different sizes and diameters need to be drilled, CNC machine tools are one of the effective solutions to save time and production costs.

In the case of drilling a registered hole, make sure to drill further on the drilled hole. The center of the inner pad will be precise, using an X-ray drill. This technique is used when through holes connect the copper layers together and drill holes in the lead components.

If the diameter of the through hole is small, the use of a mechanical drill bit will increase the breakage on the circuit board and increase the cost. Therefore, researchers have proposed a laser drilling technology to obtain precise solutions for drilling micro-holes without breaking the circuit board. When very small holes are drilled into the board and connected to the board layer, they are called micro-vias. One of the currently widely used drilling techniques is CO2 laser drilling, which is used to drill and process inner through holes.

If you want to drill holes only for connecting some copper layers instead of passing through the entire circuit board, you can perform a separate depth drilling control or pre-drill the board before the PCB lamination or laser drilling mechanism.

It is recommended to use PCB drilling experts in the initial stage of the PCB project, and at the same time determine the PCB layout and production technology in PCB manufacturing.

How can precise drilling help reduce costs?

During the drilling operation phase, the cost of drilling at the optimal speed will be reduced. When drilling holes in the circuit board, every operation should go hand in hand. By drilling faster, the speed should also be controlled to ensure that tool breakage is not a problem. This can control the ratio of drill size to plate thickness. With this, the cost can be automatically controlled by controlling the time consumed by the PCB layout.

Therefore, while working hard to reduce costs, research and development are also moving towards smooth electrical conductivity between through holes to develop an effective component installation to ensure that each drill bit has been successfully registered and completed the tool path.

The main types of drilled holes include through holes, blind holes and buried holes, each of which has a different structure and function. The proper selection and use of these types of drilled holes is critical to the performance and reliability of the circuit board.

1. Through Hole

Through holes are the most common type of holes used to connect different layers of a PCB. It is characterized by a hole that runs through the entire board and is usually plated with metal to make an electrical connection. This type of hole is not only suitable for component pin insertion, but also capable of carrying higher currents to facilitate the realization of complex circuit designs.

2. Blind Vias (Blind Via)

Blind vias are connected only to one layer of the PCB and do not penetrate the entire board. It is usually located in the upper or lower layers of the board and is suitable for designs that do not require connections from the top to the bottom. Blind vias save space and reduce the complexity of subsequent wiring, and are commonly used in High Density Interconnect (HDI) technology.

3. Buried Via

Buried vias are located between the internal layers of a PCB and are not visible on the external surface of the PCB. They are mainly used to realize the connection of signals or power supplies in multilayer boards, helping to improve the design density and integration of PCBs. Compared to through holes and blind holes, buried holes have higher space utilization efficiency.

4. Other classifications and their advantages and disadvantages

In addition to the three main types mentioned above, PCB drilled holes can also be categorized according to whether they are plated or not. Plated holes (PTH) are holes whose walls are plated with metal, enabling electrical conduction. Non-plated holes (NPTH) are used for mechanical fixing and do not involve electrical connections. Different types of holes have their specific advantages and disadvantages in terms of design and application scenarios, and need to be selected according to specific circuit design requirements.

The quality of the drilled holes directly affects the overall performance of the PCB, and any small errors may lead to board failure. Therefore, during the drilling process, the geometry, speed and noise of the drill should be strictly controlled. In addition, the cleaning process after drilling also needs to be emphasized to remove the metal chips generated to avoid problems in subsequent operations.