Introduction to PCB circuit board materials:

The classification from bottom to top is as follows:

94HB/94VO/22F/CEM-1/CEM-3/FR-4

The details are as follows:

94HB: Ordinary cardboard, not fireproof (the lowest grade material, die-punched, cannot be used as a power board)

94V0: Flame retardant cardboard (die punching)

22F: Single-sided semi-fiberglass board (die punching)

CEM-1: Single-sided fiberglass board (must be computer drilled, not punched)

CEM-3: Double-sided semi-glass fiber board (except for double-sided cardboard, it is the lowest-end material for double-sided panels. Simple double-sided panels can use this material, which is 5~10 yuan/square meter cheaper than FR-4)

FR-4: Double-sided fiberglass board

Best answer

1.c The classification of flame retardant properties can be divided into four types: 94V-0/V-1/V-2 and 94-HB

2. Pre-cured sheet: 1080=0.0712mm, 2116=0.1143mm, 7628=0.1778mm

3. FR4 CEM-3 both represent boards, fr4 is fiberglass board, and cem3 is composite substrate

4. Halogen-free refers to substrates that do not contain halogens (fluorine, bromine, iodine and other elements), because bromine will produce toxic gases when burned, which is environmentally friendly.

6. Tg is the glass transition temperature, that is, the melting point.

Circuit boards must be flame-resistant and cannot burn at a certain temperature, only softening. The temperature point at this time is called the glass transition temperature (Tg point). This value is related to the dimensional stability of the PCB board.

What is a high Tg PCB circuit board and the advantages of using high Tg PCB

When the temperature of a high-Tg printed board rises to a certain area, the substrate will change from “glass state” to “rubber state”. The temperature at this time is called the glass transition temperature (Tg) of the board. In other words, Tg is the maximum temperature (°C) at which the substrate remains rigid. That is to say, ordinary PCB substrate materials not only soften, deform, melt, etc. under high temperatures, but also show a sharp decline in mechanical and electrical properties (I think you don’t want to see this happen to your products).

Generally, the Tg of the plate is above 130 degrees, the high Tg is generally above 170 degrees, and the medium Tg is about above 150 degrees.

Usually PCB printed boards with Tg≥170℃ are called high Tg printed boards.

As the Tg of the substrate increases, the heat resistance, moisture resistance, chemical resistance, stability resistance and other characteristics of the printed board will be increased and improved. The higher the TG value, the better the temperature resistance of the plate. Especially in the lead-free process, there are many high Tg applications.

High Tg refers to high heat resistance. With the rapid development of the electronics industry, especially electronic products represented by computers, which are developing towards high functionality and high multi-layering, higher heat resistance of PCB substrate materials is required as an important guarantee. The emergence and development of high-density mounting technologies represented by SMT and CMT have made PCBs increasingly inseparable from the support of high heat resistance of the substrate in terms of small apertures, fine wiring, and thinness.

Therefore, the difference between general FR-4 and high Tg FR-4 is: in the hot state, especially when heated after absorbing moisture, the material’s mechanical strength, dimensional stability, adhesion, water absorption, and thermal decomposition properties There are differences in various conditions such as thermal expansion and thermal expansion. High Tg products are obviously better than ordinary PCB substrate materials.

In recent years, the number of customers requesting the production of high-Tg printed boards has increased year by year.

PCB board knowledge and standards (2007/05/06 17:15)

At present, the following types of copper-clad laminates are widely used in our country. Their characteristics are shown in the table below: Types of copper-clad laminates, knowledge of copper-clad laminates

There are many ways to classify copper clad laminates. Generally, according to the different reinforcing materials of the board, it can be divided into: paper base, glass fiber cloth base,

There are five categories: composite base (CEM series), laminated multi-layer board base and special material base (ceramic, metal core base, etc.). If the panel is used

The resin adhesives are classified differently, the common paper-based CCI. There are: phenolic resin (XPc, XxxPC, FR-1, FR

-2 etc.), epoxy resin (FE-3), polyester resin and other types. Common fiberglass cloth-based CCLs include epoxy resin (FR-4, FR-5), which is currently the most widely used fiberglass cloth-based type. There are also other special resins (using glass fiber cloth, polyamide fiber, non-woven fabric, etc. as additional materials): bismaleimide-modified triazine resin (BT), polyimide resin (PI) , diphenylene ether resin (PPO), maleic anhydride imine-styrene resin (MS), polycyanate resin, polyolefin resin, etc. According to the flame retardant performance of CCL, it can be divided into two types of boards: flame retardant type (UL94-VO, UL94-V1 level) and non-flame retardant type (UL94-HB level). In the past year or two, as more attention has been paid to environmental protection issues, a new type of CCL that does not contain bromine has been divided into flame-retardant CCL, which can be called “green flame-retardant CCL”. With the rapid development of electronic product technology, there are higher performance requirements for cCL. Therefore, from the performance classification of CCL, it is divided into general performance CCL, low dielectric constant CCL, high heat resistance CCL (generally the L of the board is above 150°C), and low thermal expansion coefficient CCL (generally used on packaging substrates). ) and other types. With the development and continuous progress of electronic technology, new requirements are constantly put forward for printed board substrate materials, thus promoting the continuous development of copper-clad laminate standards. Currently, the main standards for substrate materials are as follows.

①National standards At present, my country’s national standards for substrate materials include GB/T4721-47221992 and GB4723-4725-1992. The copper-clad laminate standard in Taiwan is the CNS standard, which was formulated based on the Japanese JIs standard in 1983. Released in year.

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②The main standards of other national standards include: Japan’s JIS standard, American ASTM, NEMA, MIL, IPC, ANSI, UL standards, British Bs standard, German DIN and VDE standards, French NFC and UTE standards, and Canadian CSA Standards, Australian AS standards, former Soviet Union FOCT standards, international IEC standards, etc.

Suppliers of original PCB design materials, some of which are commonly seen by everyone, include: Shengyi\Jiantao\International, etc.

● Accepted files: protel autocad powerpcb orcad gerber or real board copying, etc.

●Plate type: CEM-1, CEM-3 FR4, high TG material;

● Maximum board size: 600mm*700mm (24000mil*27500mil)

● Processing board thickness: 0.4mm-4.0mm (15.75mil-157.5mil)

●Maximum number of processing layers: 16Layers

●Copper foil layer thickness: 0.5-4.0(oz)

● Finished plate thickness tolerance: +/-0.1mm (4mil)

● Molding dimensional tolerance: Computer milling: 0.15mm (6mil) Mold punching: 0.10mm (4mil)

● Minimum line width/space: 0.1mm (4mil) Line width control capability: <+-20% ● Minimum drilling hole diameter of finished product: 0.25mm (10mil) Minimum punching hole diameter of finished product: 0.9mm (35mil) Finished product aperture tolerance: PTH: +-0.075mm (3mil) NPTH: +-0.05mm(2mil) ● Finished hole wall copper thickness: 18-25um (0.71-0.99mil) ● Minimum SMT patch spacing: 0.15mm (6mil) ●Surface coating: chemical immersion gold, spray tin, whole plate nickel gold plating (water/soft gold), screen printing blue glue, etc. ● Solder mask thickness on the board: 10-30μm (0.4-1.2mil) ● Peel strength: 1.5N/mm (59N/mil) ● Solder mask hardness: >5H

● Solder mask hole capability: 0.3-0.8mm (12mil-30mil)

● Dielectric constant: ε= 2.1-10.0

● Insulation resistance: 10KΩ-20MΩ

●Characteristic impedance: 60 ohm±10%

● Thermal shock: 288℃, 10 sec

● Warpage of finished board: <0.7%

● Product applications: communication equipment, automotive electronics, instrumentation, global positioning systems, computers, MP4, power supplies, home appliances, etc.

As 5G construction continues to advance, industrial fields such as precision microelectronics and aviation and shipbuilding have further developed, and these fields all cover the application of PCB circuit boards. With the continuous development of these microelectronics industries, we will find that the manufacturing of electronic components is gradually becoming miniaturized and thinner, and the requirements for precision are getting higher and higher. As the most commonly used processing technology in the microelectronics industry, laser welding is bound to There are increasingly higher requirements for the welding level of PCB circuit boards.

Inspection after PCB circuit board welding is very important for both enterprises and customers. In particular, many enterprises have strict requirements for electronic products. If inspection is not done, performance failures will easily occur, affecting product sales, corporate image and word of mouth. The laser welding equipment produced by Shenzhen Zichen Laser has fast efficiency, high welding yield, and post-weld inspection function, which can meet the welding processing and post-weld inspection needs of enterprises. So, how to check the quality of PCB circuit board after welding? Below Zichen Laser shares several commonly used detection methods.

01 PCB triangulation

What is triangulation? That is, the method used to check the three-dimensional shape. At present, the triangulation detection method has been developed and used and equipment capable of detecting its cross-sectional shape has been designed. However, because this triangulation detection method is incident from different lights and in different directions, the observation results will be different. Essentially, objects are inspected through the principle of light diffusion. This method is the most appropriate and most effective. As for the situation where the welding surface is close to mirror surface conditions, this method is inappropriate and difficult to meet production needs.

02 Light reflection distribution measurement method

This method mainly uses the welding part to detect the decoration, injects light inward from an oblique direction, sets a TV camera above, and then inspects it. The most important part of this operation method is how to know the surface angle of the PCB solder, especially how to know the irradiation photometric information. The angle information must be captured through various light colors. On the contrary, if it is illuminated from above, the angle measured is the reflected light distribution, and just check the tilted surface of the solder.

03 Change the angle for camera inspection

How to detect PCB after welding? To use this method to detect the quality of PCB after welding, a device with a changing angle is necessary. This device generally has at least 5 cameras, multiple LED lighting equipment, uses multiple images, and uses visual inspection conditions for inspection, so the reliability is relatively high.

04 Focus detection utilization method

For some high-density circuit boards, after PCB welding, the above three methods are difficult to detect the final result, so the fourth method, which is the focus detection and utilization method, needs to be used. This method is divided into multiple methods, such as the multi-stage focus method, which can directly detect the height of the solder surface and achieve high-precision detection. If 10 focus surface detectors are set up at the same time, the focus surface can be obtained by seeking the maximum output and detect The position of the solder surface. If it is detected by irradiating the object with a fine laser beam, a lead device with a pitch of 0.3mm can be successfully detected by staggering 10 specific pinholes in the Z direction.

In the electronics manufacturing industry, PCB (Printed Circuit Board) board serves as a “neural network” connecting electronic components, and its quality directly affects the performance and stability of the entire electronic device. As a common manufacturing problem, half-hole copper deficiency in PCB boards has complex causes and far-reaching consequences. This article will deeply analyze the reasons for the lack of copper in the half-hole of the PCB board and discuss its possible impact.
1. Analysis of the causes of lack of copper in half holes of PCB boards
Drilling process issues
Insufficient precision of drilling equipment: Low-precision drilling equipment may result in inconsistent hole sizes, rough or damaged hole walls.
Drill bit selection and wear: Unsuitable drill bits or excessively worn drill bits will affect the quality of drilling.
Improper drilling parameter settings: Unreasonable settings such as feed speed, rotation speed, etc. will also cause damage to the hole wall.

Electroplating copper process issues
Electroplating solution composition and concentration: The copper ion concentration in the electroplating solution is too low or too high, which may affect the electroplating effect.
Electroplating solution temperature and pH value: Improper temperature or pH value will affect the adhesion and uniformity of the electroplated copper layer.
Current density and time: The current density is too high or too small, and the plating time is too short or too long, which will lead to poor copper layer quality.

plate problem
Uneven material of the board: There are impurities or inconsistent fiber directions inside the board, which will affect the adhesion and uniformity of the electroplated copper layer.
Improper plate pretreatment: If the pretreatment process such as oil removal and rust removal is not in place, it will affect the subsequent electroplating effect.

Operational and Management Issues
Insufficient operator skills: The skill level of operators directly affects product quality.
Strict quality inspection: Strict quality inspection of semi-finished products and finished products may cause problematic products to flow into the next process.

2. The impact of lack of copper in the half hole of PCB board
Reduced electrical performance: Lack of copper in half holes can lead to poor circuit connections, increase resistance, and reduce the electrical performance of electronic devices.

Reduced equipment stability: Poor circuit connections may cause short circuits, open circuits and other faults during operation of the equipment, reducing the stability and reliability of the equipment.

Increased production costs: The lack of copper in half holes will increase the scrap rate and repair rate of products, leading to an increase in production costs. At the same time, more time and resources may need to be invested in technical improvements and quality control to solve this problem.

Damage to market competitiveness: PCB board quality issues are an important factor affecting a company’s brand image and reputation. If the product has quality problems such as half-hole copper shortage, it will affect customers’ trust in the company and reduce market competitiveness.
3. Solution Strategies and Suggestions
Improve equipment and process level: introduce advanced drilling equipment and electroplating equipment, optimize process parameter settings, and ensure the stability and reliability of the drilling and electroplating process.

Strictly screen and inspect boards: Strictly screen and inspect the base materials of PCB boards to ensure that the quality of the boards meets the requirements. At the same time, the pretreatment process control of the plate is strengthened to ensure that the hole wall is clean and free of impurities.

Strengthen operation and management training: improve the skill level of operators and strengthen the rigor of quality inspection. Establish a complete quality traceability system to promptly trace and analyze problematic products.

Adopt new technologies and new materials: Explore the use of new technologies and new materials to improve the manufacturing quality and performance of PCB boards. For example, advanced technologies such as laser drilling technology and nano-plating technology are used to improve product accuracy and reliability.
The lack of copper in the half hole of the PCB board is a problem that needs attention. By in-depth analysis of its causes and adopting effective solution strategies, we can reduce the incidence of half-hole copper shortage problems, improve the quality and performance of PCB boards, and thereby enhance the market competitiveness of enterprises.

With the rapid development of science and technology, electronic products have become increasingly popular. As the core component of electronic products, the importance of PCB boards (printed circuit boards) is self-evident. Among the many PCB board types, 4-layer PCB boards have attracted much attention due to their excellent performance and wide range of application fields.
Price factors of customized 4-layer PCB board
The price of customized 4-layer PCB boards is affected by many factors, including the following aspects:
Plate selection: The prices of plates of different materials and thicknesses vary greatly. Generally speaking, high-performance boards are more expensive but offer better electrical performance and mechanical strength.

Design complexity: The higher the design complexity, the more difficult the processing and the cost will increase accordingly. For example, PCB boards that require more process steps such as drilling and milling will be more expensive.

Production batch: The larger the production batch, the lower the single-chip cost. Because in mass production, equipment and human resources can be fully utilized to reduce unit costs.

Delivery time: If the customer has strict requirements on delivery time, additional expedited fees may be required.
Cost and performance trade-offs for 4-layer PCB boards
When choosing a custom 4-layer PCB board, we need to make a trade-off between cost and performance. Here are some factors worth considering:
Performance requirements: We need to clarify the performance requirements of the product. If the product has higher requirements on electrical performance, stability, reliability, etc., then we should choose higher performance boards and more sophisticated design solutions, but this may increase the cost.

Budget constraints: After clarifying the performance requirements, we need to consider budget constraints. If the budget is limited, we need to reduce costs as much as possible while meeting performance requirements. This may require us to make compromises in plate selection, design complexity, etc.

Delivery Time: Delivery time is also a factor to consider. If customers have strict requirements on delivery time, we may need to choose faster production processes and more expensive plates to ensure on-time delivery. But it can also increase costs.
The price of customized 4-layer PCB boards is affected by many factors, including board selection, design complexity, production batch size, and delivery time. When choosing a custom 4-layer PCB board, we need to make a trade-off between cost and performance to meet the product’s performance needs and budget constraints. By referring to the price list and considering various factors, we can choose the customized 4-layer PCB board that best suits our needs.

In the field of electronic manufacturing, PCB (Printed Circuit Board) serves as a bridge connecting electronic components, and its quality and stability are directly related to the performance and reliability of the entire electronic product. The immersion gold process, as a well-recognized PCB surface treatment process, provides higher stability and reliability for electronic products. Below, we will analyze the PCB immersion gold process in detail to give you a deeper understanding of its advantages and applications.

1. Overview of immersion gold technology
The immersion gold process, known as Electroless Nickel/Immersion Gold, is to plate a layer of nickel-phosphorus alloy on the surface of copper through a chemical reaction, and then plate a layer of gold on the surface of the nickel through a displacement reaction. This process not only makes the pad surface extremely flat, but also forms a protective film on the surface and sides, providing more possibilities for connecting electronic components.

2. Characteristics of immersion gold technology
Excellent weldability: The metal layer formed by the immersion gold process has good coplanarity and weldability, making the welding process smoother and reducing the risk of poor welding.

Excellent corrosion resistance: The immersed gold layer can effectively block the erosion of external oxygen, humidity and chemical substances, thereby extending the service life of the pad and improving the stability and reliability of the component.

High flatness: The immersion gold process can evenly deposit a layer of nickel and gold on the surface of the pad, making the surface smooth and flat, providing good conditions for welding.

Good electrical conductivity: Both the nickel-phosphorus alloy layer and the gold layer have excellent electrical conductivity, ensuring stable transmission of electronic signals.

3. Application of immersion gold technology
Immersion gold process PCB is widely used in electronic products such as mobile phones and computers. In these fields, the connection quality and stability of electronic components are critical to product performance and user experience. The application of immersion gold technology enables electronic products to maintain good stability and reliability in extreme environments, such as high temperature, high humidity or corrosive gas environments.

4. Control points of immersion gold process
Although the immersion gold process has many advantages, there are still some control points that need to be paid attention to during the actual production process to ensure its quality and stability. For example, the composition and concentration of the plating solution must be strictly controlled to ensure the uniformity and stability of the chemical reaction; at the same time, attention must be paid to controlling the thickness and uniformity of the coating to avoid problems such as uneven thickness or peeling of the coating.

The PCB immersion gold process provides higher stability and reliability for electronic products. By in-depth understanding of its principles, characteristics and applications, we can better utilize this process to provide strong support for the manufacturing and research and development of electronic products. In the future, with the continuous development and innovation of electronic technology, we believe that the immersion gold process will provide a stronger guarantee for the stability and reliability of electronic products.