PCB Blog - What is printed wiring board?

We use an etching process to expose the conductive insulation surface between the conductive wires to achieve the manufacturing of printed circuit boards. Without high-quality PCBs, you cannot develop efficient and modern electronic products. When it comes to electronic products, we can use the terms printed wiring board and printed circuit board interchangeably. However, there are subtle differences between sharp individuals. Therefore, these two terms refer to two different things, although the differences may prove subtle.

Printed wiring board

How to make a printed wiring board?

1. Lamination

In most cases, lamination includes a combination of substrate layers under pressure and heat to establish a laminate. As a dielectric material, the substrate can include ceramics, FR4, etc., which provides the required electrical isolation for the conductive layer. On the contrary, the prepreg is a resin-based material that can bond laminated components together. Therefore, it is not surprising to find that the prepreg layer and substrate layer are sandwiched together during the lamination process.

2. Drilling

If you do not drill holes in the printed circuit board, you cannot fix components on the circuit board. You can achieve this through the drilling process, during which the vias and components are fixed. The drilling process can be done automatically or manually, depending on your ability. However, each type uses a different set of equipment and machines. In most cases, you can use Gerber files to generate walkthrough files. It provides you with the location of the drill hole on the drill pipe.

If you plan and wish to perform plating through-hole assembly, you can use a manually operated machine for manual drilling. It requires the correct size of the drill bit to match the size of the drilled hole. However, for the automatic drilling process, specialized and programmed automatic machines use drill files to drill the required holes (required parameters). Automated drilling methods can take various forms, among which laser drilling proves its advantages. Drilling became a tool for the assembly process of printed wires, followed by.

3. Conductive Track Creation

Each form of printed wiring board relies on conductive tracks to transmit the required electrical signals. Therefore, the necessity of correctly creating this signal path cannot be underestimated. In most cases, the typical material used for conductive wiring is copper. It is ready-made and has admirable signal transmission or transmission quality. This can be consistently achieved through subtraction or addition methods.

In the additive method, copper is deposited on the surface of the substrate to match the desired pattern. On the other hand, in the subtraction method, etching copper film is used to remove unnecessary materials.

Can printed wiring boards be configured in multiple layers?

A printed circuit board is not filled, but when components are filled, it becomes a printed circuit board. The assembly process of printed wiring boards can utilize two methods and two types of electronic components. You won't miss one or two surface mount and through-hole components.

The through-hole component serves as a lead component, therefore it is necessary to drill holes on the PWB printed wiring board to secure the leads. The lead wire means the extension of the wire connecting the component to the circuit board through the welding process. It has radial loads or axial leads. The axial lead has protrusions emanating from both ends of the component and may appear to pass through the main body of the component.

On the other hand, radial leads come from a pair of protrusions on the surface of a component, although this usually occurs at the bottom.

Surface mount components do not have leads, although they have a unique mechanism to connect them to the surface of the printed circuit board. The edges or bottom surfaces of these components are metalized. The metalized surface helps to fit with the various parts of the board. Therefore, you will find these component attachments as grids or fixed forms. One incredible benefit of SMT is that it does not require drilling and relies on loading pads as an alternative, making it more suitable for fixing higher component densities. In addition, you can also enjoy their ease of use.

Can only copper be used for the traces of printed wiring boards?

Printed circuit boards must be equipped with wiring to allow signal transmission, especially for electrical types. Although you will find traces of copper as the main conductive material in PWB, other metal materials are also applicable. It can include silver, gold, etc. Traces can transmit conductive and electronic signals, therefore they must have good conductivity. Copper, except for silver and gold, has high conductivity and low resistance levels. Gold ranks higher in terms of minimum resistance to charge movement, therefore it has better conductivity than the other two materials.

What type of copper weight is suitable for printed wiring boards?

In printed circuit boards, copper plays an important role in creating conductive tracks or routing electrical signals. However, the copper used needs to be within an acceptable range to ensure the appropriate functionality specified in the design of the printed board.

Firstly, it is prudent to understand the methods of copper measurement in the electronics industry before entering the recommendation rate. The unit of measurement for copper is the ounce, but the ounce is used as a length parameter in electronics. For the sake of copper, it will describe its thickness, mainly when evenly laid per square meter.

Printed wiring boards use different copper weights, and we divide them into three types. These three classifications also define the types of printed wiring boards. It includes standard copper, polar copper, and thick copper. The weight range of standard copper is 0.5 ounces, 1 ounce, or 2 ounces. This copper thickness can be applied to standard printed circuit boards without requiring too much during the application process.

On the other hand, thick copper refers to copper with a thickness between 3 and 8 ounces. But you can always find different copper sheets, their weights are different, and you can combine them to achieve the desired weight or thickness. For example, you can use 4 pieces of 1-ounce copper to obtain a 4-ounce copper strip. Thick copper printed circuit boards are suitable for medium power or energy needs. Finally, you can obtain extremely heavy copper in a similar way to thick copper, although their applications require significant power or current transmission.

Can conformal coatings work on printed wiring boards?

Conformal coating is a resin based coating or layer that can be applied to densely packed printed wiring boards to shield unwanted external elements. These factors include moisture, dust, spills, and other external conditions that worsen the water pressure plate. The conformal coating adheres to the surface and occupies the shape of the PCB board. However, it is mainly applicable to filler boards, which proves the opposite situation of printed wiring boards. Rollers are uninhabited, therefore they are not suitable for the use of conformal coatings during their development process. In addition, the lack of features on the surface of printed wiring boards means a lack of protection from environmental or external factors.

Printed wiring boards mainly serve the following functions in various electronic products: providing mechanical support for fixing and assembling various electronic components such as integrated circuits; To achieve wiring and electrical connections or electrical insulation between various electronic components such as integrated circuits. Supply required electrical characteristics, such as characteristic impedance, etc; Provide solder mask graphics for automatic soldering, and identification characters and graphics for component insertion, inspection, and maintenance; After using printed wiring boards in electronic products, considering the consistency of the same type of printed wiring boards, this can avoid manual wiring errors and achieve automatic insertion or installation of electronic components, automatic soldering, and automatic detection. This ensures the quality of electronic products, greatly improves labor efficiency, greatly reduces costs, and facilitates maintenance.