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  • FR4, High Speed, High Frequency, Ceramic, PTFE

What is FR4 PCB?

FR-4 is the most common name in the printed circuit board industry. The people who have a preliminary understanding of FR-4 both inside and outside the industry believe that it is a kind of printed circuit board material. 

The above statement is no problem, but in fact, FR-4 is more accurately a code used in PCB materials, mainly referring to the heat resistance grade of products. Therefore, the complete meaning of FR-4 is the material specification that can self-extinguish when the resin material burns. It is a material grade rather than a name.

There are many FR-4 grade materials, which are also the most commonly used in the printed circuit board industry all the time. Undoubtedly, Viasion is no exception and uses FR-4 materials as well. Conventional single-sided printed circuit boards, double-sided printed circuit boards, including multilayer printed circuit boards, mostly use FR-4 grade materials, and most of the materials are made of TERA-FUNCTION epoxy resin, Filler, and glass fiber, which belong to composite materials.


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    • As mentioned above, FR-4 has a very wide range of applications. Generally, manufacturers, including Viasion, will evaluate the main use of products before manufacturing, and select different FR4 PCB material types according to the use and characteristics of products.
    • For example, insulation board, epoxy resin board, fiberglass board, FR-4 reinforcement board, flexible circuit board reinforcement board, flame retardant insulation board, FR-4 light board, PCB drilling pad, etc. are commonly used types.
    • They all have some common advantages and characteristics to be used in various types of products: first, the insulation is very good, which can effectively reduce the interference between components. The flatness is good, the surface is smooth, and there is no bump to affect the subsequent assembly and aesthetics. When used in high-performance electronic products, the thickness can also meet the needs of terminal products.
    • Concerning common colors of FR4 board, according to Viasion’s years of production and cooperation experience, different industries have different requirements for color. The common colors are black, white, blue, yellow, red, etc. Generally, special colors will be used in special industries. Many of our railway customers will choose red, while some sensor customers will use blue, and many controller customers will choose black, etc.
    • FR-4 is only one type of sheet material. In addition to the substrate FR-4, according to Viasion’s experience, there are four types of sheet materials, which are mainly classified according to the reinforcement materials.
    • According to Viasion’s experience, FR-4, glass cloth substrate is the most widely used and conventional.
    • CEM series composite substrate.
    • Lower than FR-4, FR-1 and FR-2, paper substrate.
    • For special substrates used for special products, the materials are more special, such as metals and ceramics. This product is special in use, but its characteristics are also obvious. They have better dielectric properties

    Types of FR4 Materials and Parameters

    The name of FR-4 and glass fiber epoxy resin copper clad laminate is too complicated. We usually call them FR-4 copper-clad laminate or CCL.

    The grading characteristics of FR-4 CCL are excellent, ranging from high to low quality. Different grades of FR-4 CCL are selected according to different products. This can not only meet the needs of high quality but also further ensure the cost performance of products. In addition, it is particularly important to know and understand our products. According to different product specifications and characteristics, choose the corresponding FR-4 CCL level, which can not only achieve the best quality but also make the price in the most competitive position!

    Regarding FR-4 CCL, Viasion usually divides them into the following grades according to their characteristics.

    FR-4 CCL series

    1. FR-4 A1 level CCL

    Because of the super high-quality factor of the standard, it can cover a wide range of industries and serve high-end products in various industries. The coverage of this level is extremely wide, from consumer level to industrial level, and even military level. For example, the following products are covered: military products, mobile phones, other communication products, computers, and other digital products, including electronic products in automobiles, as well as industrial instruments products that Viasion produces most, including measurement and security instruments. This level of CCL is the most widely used in the high-end industry, and the quality is also guaranteed, which has reached the worldwide recognition level. All our FR-4 printed circuit board are produced with the highest standards of FR4 substrate.

    2. FR-4 A2 level CCL

    The ranking of levels is from high to low. The CCL of level A2 is inferior to that of level A1 in some aspects. But it also belongs to the advanced CCL. Usually, computers used in our lives are produced at this level, including some advanced household appliances. Although A2 is slightly inferior to A1 in some performance indicators, its cost will be lower. With a reasonable application, it can further improve the cost performance of the product, so that the terminal products can have better price competitiveness in the market competition.

    3. FR-4 A3 level CCL

    This grade belongs to the middle-quality standard, and some commonly used consumer electronics will be produced under this standard, including some computer peripherals, keyboards, mice, headsets, etc. The most commonly used are electronic toys, conventional game consoles, consumer electronics, etc. The feature of this level is that it can meet the performance requirements of conventional electronic products and provide a better price advantage than the secondary standard. Therefore, some ordinary products and the most commonly used consumer electronic products will be produced under this CCL standard, which is also a CCL standard used more frequently.

    4. FR-4 Halogen-free CCL

    At present, halogen-free products are used less than other grades, but they have a very promising market. I believe that with the further development of science and technology in the future, including the further commission of environmental protection, halogen-free CCL will occupy a crucial position in the future. Halogen-free CCL is more high-end targeted, covering most industries from consumer electronics to the military industry as A1.

    CCE-3 CCL series

    Then came the CEM-3 series CCL. The product features of the CEM-3 series are different from those of the FR-4. Their advantages and features are better punching performance. Some products that need punching will use a similar feature.

    The series also has four levels. The main industries are white goods and electronic products, such as various LEDs, electronic clocks, recorders, video recorders, game consoles, etc., covering a large number of our daily electronic products. The CEM-3 series CCL also requires customers to have a clear understanding and positioning of the product, and use more appropriate grade materials.

    Viasion has rich experience in this field, and the materials of the appropriate grade can be more cost-effective and competitive in terms of price while ensuring quality.




    The shading is very good and opaque. Therefore, the main material is black.


    CEM-3 features good punching performance, so it has a good machining type. And the processing technology is the same as FR-4.


    According to Viasion's cooperation experience, this kind of material is usually used for the printed circuit board in LED.



    Like CEM-3-BK, it is opaque and has good shading performance. In addition, this type has better yellowing properties.
    Like CEM-3-BK, it has the excellent punching performance of the CEM-3 series and is well-machined with the same process as FR-4.
    It is also often used for LED customer production, The difference is that its common color is white.



    One of the general advantages is good machining and punching. The feature is that the life of the bit is longer, about twice as long as that of the ordinary bit. In addition, the processing technology is the same as that of FR-4. In addition, the electrical performance is equivalent to that of FR-4.
    Because UV blocking is compatible with UAOI, PCB production efficiency has also been improved.



    It is also excellent in machining and punching, and its service life is more than twice that of conventional drills. The processing technology is the same as FR-4, and the electrical properties are the same as FR-4.
    2) Not only the electrical properties and processing technology, but also PTH is the same as FR-4.
    According to Viasion's cooperation experience, this product has a wide range of applications, from remote control to automotive electronics, including industrial measuring instruments and test tables.

    FR4 Performance Advantages

    Because of its extensive application, FR-4 has covered most electronic products excellently, and its advantages are also widely known. For example, we know that FR-4 has good insulation, good heat resistance, and is not afraid of moisture. Besides the excellent mechanical processing performance mentioned many times, FR-4 also has many advantages and characteristics in processing technology. So FR4 PCBs are widely used in many industry areas. 

    • From the point of view of mechanics, its extensibility is very good. No matter in an environment of high temperature and low temperature, or in an environment with different humidity, it can withstand various external forces. No matter bending, stretching, or being impacted, it can still maintain good stability. The loss coefficient is also very low, and the DF value is about 0.0024.
    • The adaptability of FR-4 is very good. Whether it is a relatively low viscosity or a high melting point solid, FR-4 can be well adapted and meet the needs of products.
    • The curing temperature range is wide, from 0 ℃ to 180 ℃. FR-4 can be fixed at the temperature required by the product. The fixed temperature is very flexible, which greatly facilitates manufacturing. The melting point of the pressing plate is 203 °. So FR-4 printed circuit boards can be used in high temperature applications such as power modules.
    • Very low shortening rate. According to Viasion's production experience, it is usually less than 3% during curing, because there is no volatile substance during processing.
    • Because of the strong hydroxyl and ether bond in the FR-4 material, it has good adhesion. In addition, because the internal stress between molecules is small, its adhesion is further strengthened.
    • Excellent heat resistance. The heat resistance can reach more than 150 °, so the product has a wide coverage and can be used in electronic products in all walks of life. And the dielectric constant is very stable, about 2.34.

    FR-4 Quality Control

    In the production of FR4 circuit, the most common problem is board warping after PCB completion. We will share our experience in warping prevention based on Viasion’s experience.

    The use of materials is crucial. The first point of materials is the formulation of resins. Viasion usually chooses resins and curing agents with better flexibility, which is the first and crucial step. The selection of materials lays an important foreshadowing for the production quality of subsequent products.

    After the selection of resin is decided, the next step is the selection of substrate. According to Viasion’s production experience, we found that when using paper-based CCL, the degree of warpage is different in different suppliers. Some are upright and some are reversed. Based on our experience, we combined the paper-based CCL that produces upright and reverse warping, and finally found that the flatness of the finished product is very good, but only for paper-based CCL.

    The above conditions are not found for glass fiber cloth, but the materials produced by different manufacturers have a certain impact on the warpage, which needs to be carried out according to the procurement experience of their respective manufacturers.

    High-quality products cannot be separated from strict control of various parameters during production, and it is crucial to ensure the consistency of resin content and gelation time of the prepreg to ensure the flatness of PCB. Viasion also found a more appropriate control index after a lot of practice.

    When applying glue, try to control the size of the external force. It is better to be smaller than too big. Secondly, the materials from different manufacturers should be distinguished and should not be mixed randomly. In addition, materials of the same specification should be used. If the semi-cured sheets comes from different manufacturers, it should also be avoided to mix them, because such mixture will produce different tensions and ultimately affect the flatness of the product.

    When PCB is hot pressed, Viasion usually uses heat transfer oil for heating, which will make the temperature difference of hot pressed plate smaller. When controlling the temperature rise, stability must be guaranteed first. Too fast or too slow is not good for the final PCB. To reduce the loss of gel during operation, pay attention to the fluidity and gelation time of the prepreg.

    In addition, attention should be paid to the setting of the hot pressing plate to ensure uniform heating, otherwise, the flatness of the final PCB will be greatly affected.

    To produce a satisfactory and flat PCB, it is necessary to design a reasonable preheating temperature and pressure rate. In addition, in the selection of stainless steel plate thickness, try to select materials with better thickness and hardness, which will help to ensure the quality of the final product.

    According to Viasion’s observation, the warpage of the outer layer is usually greater than that of the inner layer, which is considered to be caused by the cooling rate. According to Viasion’s experience, we usually control the cooling rate by subsection. Instead of directly using cold water and cold oil for cooling, we first use warm water for cooling to avoid excessive temperature differences between the inner and outer layers, leading to warping of the inner and outer layers.

    In terms of pressure, Viasion usually uses a vacuum press, so that molecules in PCB can be more easily discharged from it, to achieve a multiplier effect with half the effort. With lower pressure, it can obtain products with higher density. And lower pressure will also reduce internal stress, which can further reduce the warpage of the finished product.

    In addition, low pressure can also ensure less glue flow and further avoid warping.

    CCL must pay attention to the sealing during storage. The moisture-proof sealed packaging is the best, and its stability should be guaranteed during storage and placement. It should be placed flat, avoiding side or vertical, and do not place heavy objects on it. Viasion has rich experience in storage. Even if CCLs are stacked, flat isolation plates should be placed in them, otherwise, deformation will occur easily.

    The above is Viasion’s production experience. Production based on the above experience can greatly avoid CCL warping.

    Features of FR-4 to Consider When Choosing FR4 PCB

    • FR-4 is a low-cost material.
    • It has a high dielectric strength, which contributes to its electrical insulation properties.
    • The material has a high strength-to-weight ratio and is light in weight.
    • It is moisture-proof and also has a relative temperature.
    • The material has good electrical loss properties.
    • FR4 does not absorb water and is therefore also suitable for various marine PCB applications.
    • The FR-4 material is yellow to light green in color, making it ideal for any application.
    • All these properties make FR-4 materials suitable for a variety of environments.

    Uses and Applications of FR4 PCB

    FR-4 materials are now widely used in military, communication, computer, digital circuits, industrial instruments, automotive circuits, and other electronic products, and their performance indicators can meet the needs of general industrial electronics.


    FR-4 is also by far the most frequently used grade and material in PCB electronic industry production, covering a wide range, from simple consumer electronics to military products. With the gradual development and progress of the electronic industry, halogen-free environmental materials in FR-4 molecules are also increasingly popular.

    FR4 PCB Specification of Viasion

    FR-4 PCB specifications of Viasion include the following types of material: High TG FR4, Halogen-free FR4, and High Speed FR4. Please contact us freely for any of your FR-4 printed circuit boards needs. 

    Why Choose Us?

    Viasion has provided PCB & PCBA manufacturing services since 2007. Viasion also has rich production experience and cooperation experience in FR-4. As mentioned above, Viasion will evaluate the primary use of the electronic product before carrying out the manufacturing process and choose different types of FR-4 material depending on the use and characteristics of the product to ensure that our work is done meticulously and rigorously. The following points explain why you should choose Viasion as your FR4 PCB supplier.

    Reliable reputation

    We have 16 years of experience in supplying FR-4 printed circuit boards, trusted by 1000+ customers all over the world. Both the quality of our products and the high standard of service are highly recognized by the market.

    Superior quality

    There is a well-equipped workshop and several sets of advanced production facilities in our company, which ensures the superior quality of products. What’s more, we have attained ISO9001:2015 and UL certification. In our work, we insist on strictly controlling each process, pay attention to details, and devote ourselves to improving the quality of our products.

    All-around services

    Viasion has established a sound service system and service team. Over the years, we have been cooperating with our customers on an equal, mutually beneficial, and win-win basis. Our company offers you more than just products. Our goal is to become a full range of experts supplying FR-4 printed circuit boards and other types of PCB boards.
    We hope to cooperate with you. You are welcome to contact us! 

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    Viasion Technology is your trusted partner & one-stop shop for PCB fabrication, components sourcing, PCB assembly and electronic manufacturing. With more than 16 years of experience, we have been supplying high-quality PCBs with competitive pricing for 1000+ customers worldwide. Our company is ISO9001:2015 Certified & UL Listed, and all our products are 100% E-tested and inspected by AOI & X-RAY to meet the highest industry standards. So please get an instant quote from our sales team now, and we will take care of the rest.

    Frequently Asked Questions

    An FR-4 PCB refers to a printed circuit board made of FR4 materials. FR4 is a kind of glass-reinforced epoxy which meets the UL 94V-0 rating.

    FR-4 printed circuit board material are the most widely used circuit board material. It has the following properties:
    1. Meet UL 94V 0 flammability rating;
    2. High reliability for electronic devices;
    3. High processing performance, FR4 PCBs can be produced from 1 layer to 100 layers;
    4. Cost-effective, so FR4 circuit boards are widely used in almost all industrial areas.

    TG means glass fiber deformation temperature from solid to liquid. The typical TG of FR4 PCB material is 130-140°C. But higher TG FR4 materials are also commonly used, such as: FR4 TG130°C, FR4 TG150°C, FR4 TG170°C, FR4 TG180°C or may over TG200°C. All these FR4 substrates meet UL 94V-0 standards.

    The most usual FR4 PCB thickness is 1.6 mm, but we can produce FR4 PCBs from 0.1 mm to 10.0 mm.

    There are no specified requirements for the solder when assembling components on an FR-4 PCB. The commonly used solder is a lead-free alloy that contains 96.5% tin, 3% silver, and 0.5% copper.

    1) If we talk about the copper conductors, a single-sided FR-4 PCB only has copper foil on one side, while a double-sided FR-4 PCB has copper foil on both sides.
    2) If we talk about electronic components on PCBs, the solder joints of a single-sided FR-4 PCB are usually on one side only, and the other side is for inserting components. A double-sided FR-4 PCB can be soldered on both sides.
    3) A single-sided FR-4 PCB has only one layer of copper trace, while the double-sided FR-4 PCB can be routed on both sides and connected to each other by plated vias. So, double-sided FR-4 boards can design more functions. Consequently, the double-sided FR-4 PCB is more suitable for complex circuits than the single-sided FR-4 PCB.
    4) Apparently, a double-sided FR-4 PCB is more expensive than a single-sided FR-4 PCB if the other parameters are the same.

    Besides consumer electronics, FR-4 PCBs are also used in automation, industrial control, telecommunications, IoTs, robotics, test and measurement, medical, safety and security equipment, automotive, aerospace, LED lighting, etc. Generally speaking, FR-4 PCBs are the most widely used circuit boards, it is used almost in all electronic devices. 

    Operators should be trained and standard operation of relevant processes should be demonstrated to them.
    The factory should carry out the maintenance and overhaul of machines and equipment regularly.
    We should take precautions to prevent damage caused by dust, noise, corrosive potions, and exhaust gases.
    Workers should be equipped with labor protection appliances during the production of FR-4 PCBs. For example, they should wear goggles, acid-resistant gloves, and aprons when adding potions, wear masks in a workshop with exhaust gases and wear earplugs in noisy workshops.

    Usually, almost all types of components can be mounted on an FR-4 PCB. There are no specified requirements for components that can be mounted on an FR-4 PCB. Which components to be mounted is determined by the customer’s requirements and the characteristics of the electronic products.

    The properties of the FR-4 material make it versatile and its price is affordable.
    Excellent electrical performance
    Meet UL94V-0 flammability rating
    The structural stability can be ensured.
    The durability of an FR-4 PCB is high.
    Strong mechanical properties.
    UV blocking/AOI compatible
    Lead-free compatible
    Cost-effect so it is the most widely used material

    Generally, the maximum temperature an FR-4 can handle is between 90 °C and 110 °C. But there are some advanced and reinformed FR-4 materials that have an operating temperature of up to 150 °C.

    The most common thicknesses available for FR-4 PCBs are 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm, 1.6mm, 1.8mm, 2.0mm.

    The typical lead time for an FR-4 PCB is 1-3 weeks. More details as follows:
    Quick turn FR-4 PCB service takes 1-5 days.
    It takes 1-2 weeks for prototype and small series production.
    Two or four weeks are taken for mass production.
    However, the lead time greatly depends on the PCB material and the order quantity. Please contact our sales team if you want to know the price and lead time to produce your FR4 circuit boards.

    There is no minimum order quantity for an FR-4 PCB in Viasion. Regardless of the order quantity, we will provide high-quality products and serve you wholeheartedly.