what is Fr4 Circuit Board? (fr4 material guide 2020)2020-10-26
What is Fr4 Circuit Board? (Fr4 Material Guide 2020)
What’s the difference between FR1 and FR2?
Basically, they are the same thing. FR1 has a higher glass transition temperature of 130 ° C instead of 105 ° C for FR2. Some manufacturers who make FR1 will not make FR2 because the cost of production and application are the same and there is no advantage in making both materials. Similarly, pcb manufacturers use Fr4 Circuit Board for high technology electronics.
What is FR2?
Phenolic-filled paper base material. This material has a flammability class UL94-V0.
What is FR3?
FR3 is mainly a European product. Basically, it is FR2, but epoxy is used as a filler instead of phenolic resin. The main layer is paper.
What is Fr4 Circuit Board?
Fr4 Circuit Board is fiberglass. It is the most common PCB material. FR4 1.6mm thick consists of 8 layers of # 7628 fiberglasses. The manufacturer’s logo / designation of the red flammability class is located in the middle. The temperature for using this material is 120 – 130 ° C.
What is FR5?
FR5 is fiberglass similar to FR4, but the temperature of use of this material is 140 – 170 ° C.
What is CEM-1?
CEM-1 is a paper backed laminate with one layer of # 7628 glass fabric. This material is not suitable for plating through holes.
What is CEM-3?
CEM-3 is most similar to Fr4 Circuit Board. Construction: fiberglass mat between two outer layers of # 7628 glass fabric. CEM-3 milky white very smooth. The price of this material is 10-15% lower than that of FR4. The material is easy to drill and stamp. It is a complete replacement for FR4 and has a very large market in China.
What is the G10?
G10 is now not fashionable material for standard printed circuit boards. This is fiberglass, but with a different filler than FR4. G10 is available only in UL94-HB flammability class. Today, the main field of application is wristwatch boards, as this material is easily stamped.
What are prepregs in printed circuit board?
Prepreg is an epoxy resin coated fiberglass fabric. The applications are as a dielectric in multilayer printed circuit boards and as a starting material for Fr4 Circuit Board. 8 layers prepreg are used in one 1.6mm FR4 sheet. The center layer usually contains the red company logo.
What does FR or CEM stand for?
CEM – a material consisting of epoxy resin (Composite Epoxy Material); FR – Fire Retardent.
Is Fr4 Circuit Board really green?
No, it is usually transparent. PCB green is the color of the solder mask.
Does the color of the logo mean anything?
Yes, there are red and blue logos. Red means UL94-V0 flammability class and blue means UL94-HB flammability class. If you have a material with a blue logo, then this is either XPC (phenolic paper) or G10 (fiberglass). In FR4 1.5 / 1.6 mm thick, the logo is in the middle layer (# 4) with an 8 layer construction.
Does the orientation of the logo mean anything?
Yes, the focus of the logo shows the direction of the underlying material. The long side of the board must be oriented towards the base. This is especially important for thin materials.
What is UV Blocking Laminate?
It is a material that does not transmit ultraviolet rays. This property is necessary in order to prevent false exposure of the photoresist from the side opposite to the light source.
What laminates are suitable for plating through holes?
CEM-3 and Fr4 Circuit Board are the best. FR3 and CEM-1 are not recommended. For others, metallization is not possible. (Of course, you can use “silver paste plating”).
Is there an alternative for plating through holes?
For hobby / DIY, you can use rivets, which can be purchased at radio stores. There are several other methods for low density boards such as wire jumper, etc. A more professional way is to obtain connections between layers by the method of “metallization with silver paste”. The silver paste is silk-screened onto the board, creating a metallized through-hole. This method is suitable for all types of laminates including phenolic paper and the like.
What is material thickness of printed circuit boards?
Material thickness is the thickness of the base of the laminate excluding copper foil thickness. This is essential for multilayer board manufacturers. Basically, this term often comes for thin Fr4 Circuit Board laminates.
Attention! This data may not be complete. Many manufacturers also produce laminates that are not fully ANSI compliant. This means that the current DIN / JIS / BS specifications, etc. may differ. Please check that the standard of the particular laminate flooring manufacturer best suits your requirements.
What is CTI?
CTI – Comparative Tracking Index. Shows the highest operating voltage for a given laminate. This becomes important in products that operate in high humidity environments such as dishwashers or cars. A larger index means better protection. The index is similar to PTI and KC.
“Prepreg” is a semi-cured epoxy resin coated glass fabric (B-stage). It comes in a dielectric in multilayer printed circuit boards and as a raw material in the production of Fr4 Circuit Board fiberglass. When the prepreg heats up, the resin becomes fluid and then hardens without lowering the temperature. The time it takes for the resin to go from liquid to solid at a given temperature is called the “gel time”.
Material features Fr4 Circuit Board
- Excellent bond strength.
- AOI compatible / UV blocking (for yellow material).
- Excellent processing parameters in a wide process window.
- Excellent fluidity and resin application parameters.
- Low moisture absorption.
- Good storage stability.
- Storage conditions
For storage within 3 months, keep the temperature at 20 ° C and 50% RH; within 6 months – temperature 5 ° С and relative humidity 50%.
In case of long-term storage, keep the prepreg at room temperature for 24-48 hours before use, and always keep it wrapped in a moisture-proof material. Avoid exposure to UV radiation and bright light.
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