Posts Tagged ‘fr4’

Thursday, October 24th, 2024

CEM1 PCB is a composite epoxy metal-based copper-clad laminate. It is made of flame-retardant epoxy resin impregnated paper or glass fiber cloth as the substrate, covered with copper foil on one side, and hot-pressed. CEM1 PCB has good mechanical strength, electrical properties and heat resistance, and is suitable for the manufacture of various electronic devices.

What is a CEM composite epoxy material?

CEM composite epoxy material is a material used for printed circuit boards (PCBs), mainly composed of epoxy resin, glass fiber cloth, wood pulp paper and copper foil. Its main features are excellent mechanical processing performance, lower cost than glass fiber cloth copper-clad laminate, and better performance than paper-based copper-clad laminate.

Types and applications of CEM composite epoxy materials:

CEM composite epoxy materials mainly include types such as CEM1 and CEM-3. CEM1 composite materials are made of glass fiber fabric surface and paper core combined with epoxy resin, and are mainly used in the printed circuit board industry.

CEM-3 is a composite copper-clad laminate that uses glass cloth and glass felt as a composite substrate. Unlike FR-4, its production process is similar to FR-4, but it uses a different substrate.

What type of PCB is FR4?

FR4 is a copper-clad laminate that is mainly used in printed circuit board (PCB) manufacturing.

FR4, which stands for Flame-Retardant 4, is a composite material made of glass fiber and flame-retardant epoxy resin. It has excellent flame retardant properties and stable electrical properties, so it is widely used in the electronics industry.

FR4 board is mainly made of quadrifunctional epoxy resin plus filler and glass fiber cloth. Epoxy resin has good adhesion and electrical insulation, while glass fiber cloth provides mechanical strength and dimensional stability.

The specification standard of FR4 board is formulated by NEMA (National Electrical Manufacturers Association), where FR represents the flame retardant grade.

FR4 copper clad laminate is divided into different grades according to performance and quality, mainly including:

FR-4 A1 grade copper clad laminate: mainly used in high-end electronic products such as military industry, communications, computers, digital circuits, industrial instruments and meters, and automotive circuits.

FR-4 A2 grade copper clad laminate: suitable for ordinary computers, instruments and meters, high-end home appliances and general electronic products, and its performance indicators meet the needs of general industrial electronic products.

FR-4 A3 grade copper clad laminate: mainly used in the home appliance industry, computer peripheral products and general electronic products. On the premise that the performance meets the requirements, the price has a competitive advantage.

FR-4 A4 grade copper clad laminate: It is a low-end material, but it can still meet the needs of ordinary home appliances, computers and general electronic products, and its price is the most competitive.

FR-4 B grade copper clad laminate: The quality stability is poor, suitable for smaller circuit board products, and the price is the lowest.

In summary, FR4 is a high-performance copper clad laminate material, which is widely used in various electronic products and is favored for its excellent flame retardant properties and stable electrical properties.

What is the difference between CEM1 and FR4?

The main differences between CEM1 and FR4 are in terms of material composition, mechanical properties, electrical properties, heat resistance and cost.

Material composition and manufacturing process:

FR4: It is composed of glass fiber and epoxy resin. Its manufacturing process is mature and the cost is relatively low, so it is widely used.

CEM1: It is a composite epoxy resin material with wood pulp fiber paper or cotton pulp fiber paper as the core material, covered with glass fiber cloth on the surface, and impregnated with flame-retardant epoxy resin. Compared with FR4, CEM1 has slightly inferior mechanical properties and heat resistance, but lower cost.

Mechanical properties and heat resistance:

FR4: It has high mechanical strength and rigidity, suitable for complex electronic equipment and structures. It has good heat resistance and can remain stable at higher temperatures.

CEM1: It has slightly lower mechanical strength and is suitable for electronic products with low performance requirements. Its heat resistance is also relatively poor.

Electrical properties:

FR4: has excellent electrical properties, including high insulation resistance and low dielectric constant, suitable for electronic devices with high frequency and high-speed transmission.

CEM1: The electrical properties are slightly inferior to FR4, and it is not suitable for high-frequency applications.

In summary, FR4 performs better in mechanical properties, electrical properties and heat resistance, and is suitable for electronic devices with high performance requirements; while CEM1 has more advantages in cost and is suitable for electronic products with low performance requirements.

What are the advantages of CEM1 PCB?

The main advantages of CEM1 PCB include the following aspects:

Excellent mechanical properties: CEM1 PCB has excellent mechanical properties, and its impact force can reach 0.093 inches. Compared with paper grades, CEM1 is easy to stamp and has higher bending strength.

High cost-effectiveness: The cost of CEM1 PCB is lower than that of glass fiber cloth copper clad laminate, so it has significant advantages in cost control.

Good electrical performance: The electrical performance of CEM1 PCB is also excellent, suitable for various electronic devices, especially in the LED lighting market, CEM1 is able to achieve the best balance between heat dissipation performance and PCB cost.

Wide range of applications: CEM1 PCB is widely used in the printed circuit board industry, especially in some low-end and mid-range products.

What are the disadvantages of CEM1 PCB?

Mechanical durability: CEM1 printed circuit board lacks good mechanical durability.

Production applicable type: CEM1 can be used to produce single-sided PCBs because its laminate is not compatible with through-holes.

Fragility: PCBs produced by CEM1 are very fragile and can easily break if not handled properly.

Substitutability and limitations: FR-4 can be used to replace CEM1. But in case FR-4 needs to be replaced, CEM1 can only replace single-layer FR-4 PCBs with limited functions.

Why is CEM1 PCB single-layer?

The main reason why CEM1 PCB is single-layer is due to its material properties and cost-effectiveness.

CEM1 PCB is a single-layer printed circuit board. Its material properties determine that it can only be made into a single-layer structure. CEM1 material is mainly composed of glass cloth and epoxy resin. This material structure makes the PCB board have only one conductive layer.

Although technological advances have made multi-layer PCBs possible, PCBs made of CEM1 materials still maintain a single-layer structure, mainly because of its cost-effectiveness and design complexity.

The design and manufacturing of single-sided PCBs are relatively simple and low-cost, suitable for low-density design requirements. Since there is only one conductive layer, more winding is required during wiring design, but this is acceptable in low-density designs.

In addition, the manufacturing process of single-sided PCBs is relatively fast and low-cost, which is one of the reasons why it is widely used.

What are the applications of CEM1 PCB?

Simple applications and LED lighting: It can be used to make simple applications such as toys, remote controls, calculators, and home appliances. At the same time, headlights, indicator lights, and brake lights in LED lighting can also be made of CEM1 PCBs.

Computer Components: Computers are sensitive to heat, and LED CEM1 PCBs can conduct heat effectively, so computer components such as CPUs, floppy disk drives, and power supply units are made of them.

Industrial and Electronic Equipment: Used in the production of industrial controls, converters, instrumentation, UPS systems, hard disks, and telephone systems.

Medical Field: Tools used to perform surgeries are made of CEM1 LED PCBs, and even medical scanning technology uses such PCBs to manufacture scanning equipment.

As a special type of PCB, CEM1 PCB is widely used in the electronics industry for its good mechanical strength, electrical properties, heat resistance, and low cost. As electronic equipment continues to develop, CEM1 PCBs will also continue to innovate and develop to meet the needs of electronic equipment.

What is the glass transition temperature and Its Significance?

The glass transition temperature (Tg) refers to the temperature corresponding to the transition from the glass state to the high elastic state. The glass transition is an inherent property of amorphous polymer materials and a macroscopic manifestation of the transformation of the polymer motion form. It directly affects the performance and process performance of the material. Therefore, it has long been the main content of polymer physics research.

The glass transition temperature is of great significance to the application of polymers. Above this temperature, polymers show elasticity; below this temperature, polymers show brittleness. This characteristic must be considered when used as plastics, rubber, synthetic fibers, etc.

The glass transition temperature of mainstream FR-4 boards is approximately between 130-140℃. In the PCB manufacturing process, the temperature needs to be strictly controlled to avoid exceeding the glass transition temperature to ensure the quality of the product.

Is higher glass transition temperature better?

In PCB manufacturing, the higher the glass transition temperature (Tg), the better. ‌

The glass transition temperature is an important performance indicator of polymer materials, which determines the changes in the physical and chemical properties of the material at a specific temperature. When the temperature of the polymer is lower than its glass transition temperature, the material exhibits hard and brittle characteristics, similar to the glass state; when the temperature is higher than the glass transition temperature, the material becomes soft and exhibits elasticity similar to rubber or leather. This state change has a direct impact on the performance during PCB manufacturing and use.

1. ‌ Temperature deformation resistance ‌:

The higher the Tg value, the stronger the material’s temperature deformation resistance. This means that in a high temperature environment, such as during SMT welding, the PCB substrate is not easy to deform, thereby maintaining dimensional stability, which is crucial to ensure the reliability and long-term use of the circuit board.

2. ‌ Electrical performance and mechanical strength: ‌

The high or low Tg value directly affects the electrical performance and mechanical strength of the PCB. High Tg materials can maintain good physical and chemical stability at high temperatures, thereby maintaining the electrical properties and mechanical strength of the circuit board, which is crucial to improving the quality and reliability of the product.

3. Safety:

PCB materials with high Tg values are not easy to soften or melt at high temperatures, thereby improving the safety and durability of the circuit board and reducing the risk of short circuits or other damage caused by high temperatures.

In summary, choosing PCB materials with higher Tg values is one of the key factors to ensure that the circuit board maintains stable performance and safety in complex manufacturing and use environments.

What is glass transition temperature vs melting temperature?

In PCB manufacturing, glass transition temperature and melting temperature are two different physical properties that describe the state changes of materials under different conditions. ‌

The glass transition temperature (Tg) mainly involves amorphous materials or amorphous regions in partially crystalline materials. At this temperature, the physical state of the material changes from glass to highly elastic.

The melting temperature (melting point) mainly involves the melting process of crystalline materials. For crystalline polymers, the melting point marks the temperature at which the molecular chain begins to move, that is, the material changes from solid to liquid. The melting point is related to the crystallinity and lattice structure of the material and is a physical property unique to crystalline materials.

In short, the glass transition temperature mainly affects the amorphous region in amorphous or partially crystalline materials, while the melting temperature mainly affects crystalline materials and involves the melting process of the entire crystal. These two temperatures reflect the different physical state changes of different materials when heated.

How do you determine the glass transition temperature?

Expansion method, thermomechanical method, differential scanning calorimetry (DSC), DTA method, dynamic mechanical property analysis (DMA) method, nuclear magnetic resonance method (NMR).

Differential scanning calorimetry (DSC) is the most traditional and commonly used measurement method. It measures the relationship between the power difference (heat flow rate) and temperature between the sample and the reference material, and then obtains the glass transition temperature of the material;

Dynamic mechanical analysis (DMA) is the most sensitive method. It measures the sinusoidal alternating stress of constant amplitude applied to the sample, observes the change of strain with temperature or time, and calculates the mechanical parameters to characterize the elastomer;

Thermomechanical analysis (TMA): Use a probe with good sensitivity to measure the expansion coefficient of the material, and measure the glass transition temperature of the material based on this change.

What is the difference between TM and Tg?

In the PCB industry, TM and Tg are two different parameters, representing two different physical properties.

Tm: melting point; m is the melting point of crystalline polymers, that is, the temperature at which crystalline polymers melt. It is the highest use temperature of crystalline polymers when used in plastics and fibers, and it is also their heat resistance temperature and the lowest temperature for molding processing.

What is the Tg of polyurethane?

The glass transition temperature (Tg) of polyurethane is not a fixed value, but a physical quantity determined by the type of resin.

‌There are many types of polyurethane, including polyether, polyester, polyimide, polyurea, etc. Each type of polyurethane has its own specific glass transition temperature.

Shape memory polyurethane has a small volume expansion rate at temperatures below Tg, but increases at temperatures above Tg, which shows the characteristics of its glass transition temperature. Therefore, to determine the glass transition temperature of a specific polyurethane, its specific chemical structure and application field need to be considered.

What is Tg for epoxy?

The Tg value of PCB epoxy resin is usually between 130℃ and 170℃. ‌

The Tg value (glass transition temperature) of PCB (printed circuit board) epoxy resin is an important performance indicator, which reflects the change in the physical state of the material when heated. According to different application requirements, the Tg value of PCB epoxy resin can be divided into several grades:

‌TG130‌: The temperature resistance of this type of board is about 140℃. Common Tg value boards of this type are Shengyi S1141 and Jiantao KB-6164F.

TG150: A medium Tg board with a temperature range of 150°C to 170°C. Common boards with this type of Tg include Shengyi S1141 150 and Jiantao KB-6165F.

TG170: A high Tg board with a temperature range of over 170°C. Common boards with this type of Tg include Shengyi S1170 and Jiantao KB-6167F.

Selecting the right Tg value is critical to ensuring the performance and reliability of the PCB. Although boards with high Tg values are relatively expensive, their superior temperature resistance is indispensable in applications that require higher temperatures, such as aerospace. In addition to Tg values, other factors should be considered when selecting PCB boards, such as thermal decomposition temperature (Td), which is another important indicator for evaluating the stability of boards at high temperatures.

Conclusion:

High Tg represents high heat resistance. Electronic products represented by computers are developing towards high functionality and high multi-layer, which requires higher heat resistance of PCB substrate materials as an important guarantee. BEST Technology focuses on manufacturing high-performance PCB circuit boards and is far ahead in the industry. It has professional production equipment and 18 years of design experience, and has high quality requirements for products.