Pcb multi-layer circuit board manufacturers have a professional technical research and development team, master the industry’s advanced process technology, and have reliable production facilities, testing facilities and physical and chemical laboratories with all kinds of functions. The FR-4 we are talking about here is the most commonly used sheet type in the production of pcb multilayer circuit boards.
Very superficial, the most widely used copper clad laminate and prepreg in the world is NEMA named FR4
about 14% of the total output is single-sided or double-sided FR-4 board, and the remaining about 40% of the multi-layer board is thin FR -4 laminates. The historical end of FR-4′s dominance of the market is mainly due to the fact that it greatly exceeds paper-based laminates in thermal properties, improved moisture and chemical resistance, higher flexural strength and good peel strength. . FR4 is the first laminate that can be used for spring-through-hole double-sided panels because of its resistance to moisture and chemical exfoliation. Plus, the FR-4′s value for money is unbeatable. Over the years, the industry has presumed that FR-4 will give way to newly developed laminate materials suitable for higher assembly density. However, because of cost constraints, circuit board designers are still looking for ways to use FR-4 in high-density assemblies.
The reinforcing material used for FR4 laminates is electronic glass Wib (E-glass). Because of its particularly good mechanical properties, satisfactory electrical insulation properties, heat resistance, moisture resistance and acid resistance, E-type glass fiber cloth has become a very good electrical reinforcement material. All fabrics used in FR4 have a smooth surface structure according to the method of weaving a basket, and the surface is coated with a layer of paint to strengthen the joint between glass fibers and natural resins. During the shrink weaving process, the thickness and number of glass fibers are determined. The basic weight and thickness of the finished fabric are determined, the thickness of the glass fiber cloth used for the printed board is mostly from 6 to 172m, and the prepreg composed of the glass fiber cloth determines the thickness of the laminate. Generally, the thickness of the FR4 laminate is bam~1L57mm (increasing at intervals of 25pm), and the specific thickness depends on the type of glass fiber cloth and the natural resin content of the semi-chemical sheet used. The performance of a laminate is primarily determined by the structure, since the purchaser has to make careful demands, and for a given thickness, there are numerous structures that can meet the given tolerances. Variations in the natural resin content (sometimes referred to as the ratio of wood to fiberglass cloth) will affect the properties of the laminate.
The overall system of epoxy natural resin is composed of various active epoxy compounds, and the standard bifunctional epoxy natural resin (each of its components) is obtained through the synthesis of a single epoxy group and tetrabromofluorescein A (TBPA). There are two reactive epoxy oxygen compounds on the polymer chain), as shown in Figure 4.6. The chain length between the groups determines the rigidity of the laminate and the thermal properties of the laminate. During the curing process, the epoxy oxygen groups react with the curing agent to initiate a three-dimensional polymer matrix. As a part of the polymer chain, Wakamura bromine is added to TBBPA, which makes TBPA have special flame retardant properties. According to Underwriters Laboratories
(Underwriters Laboratory) UL94 test, in order to make the finished laminate with V0 level of flame retardancy, it is necessary to add bromine between 16% and 21% by weight.
The pcb circuit board products in pcb multilayer circuit board manufacturers cover 2-28 layer boards, HDI boards, high TG thick copper boards, soft and hard bonding boards, high frequency boards, mixed media laminates, blind buried via boards, metal substrates and no Halogen plate. The advantage of Shenzhen bus circuit lies in a variety of mid-to-high-end wrenches, and the price is still very affordable, and it is already in a leading position in the pcb industry.
Post time: Aug-08-2022