Nowadays, electronic products can be touched everywhere, and it is closely related to people's lives. With the development of electronic equipment in the direction of miniaturization, light weight, multi-function and environmental protection, the printed circuit board as its basis is also developing in these directions, and the materials used for printed boards should also adapt to the needs of these aspects.
There are many kinds of materials used in the production of pcb printed circuit boards, which can be divided into two categories: main materials and auxiliary materials according to their applications. Main material: raw materials that become part of the product, such as copper clad laminates, solder resists, inks, marking inks, etc., also known as physicochemical materials.
Auxiliary materials: materials consumed in the production process, such as photoresist dry film, etching solution, electroplating solution, chemical cleaning agent, drilling pad, etc., also known as non-physical materials.
PCB power board is an important mechanical component of electrical appliances or electronics made of copper foil substrate (Copper-clad Laminate, CCL for short) as raw material. It is widely used. Common substrates are divided into: 94HB, fireproof Plate (94VO, FR-1, FR-2), half glass fiber (22F, CEM-1, CEM-3), full glass fiber (FR-4).
FR-1: halogen-free sheet, which is beneficial to environmental protection; high leakage resistance fluctuation index (above 600 volts, special requirements need to be made); suitable punching temperature is 40-70 ℃; bow curvature and twist rate are small and stable.
FR-2: Excellent resistance to leakage traces (above 600V), low cost and wide range of use; excellent moisture and heat resistance; suitable punching temperature is 40-70 ℃; printed circuit board FR-2 bow curvature, twist rate is small and stable; the dimensional stability is excellent.
CEM-3: Excellent machinability, can be punched. The electrical performance is comparable to FR-4, the processing technology is the same as that of FR-4, and the wear rate of the drill tip is smaller than that of FR-4; multi-level resistance to leakage traces; it meets the requirements of IPC-4101A.
FR-4: Halogen-free, the content of bromine and chlorine is less than 0.09%, no antimony and red phosphorus, no toxic components remain when burned; the sheet is harder than KB-6160 (Harder than KB-6160).
Environmentally friendly products are the need for sustainable development, and environmentally friendly printed boards require environmentally friendly materials. For the copper clad laminate, the main material of the printed board, the poisonous polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) are prohibited in accordance with the EU RoHS regulations, which involves the cancellation of bromine-containing flame retardants for the copper clad laminate.
In addition to being non-toxic, environmentally friendly products are also required to be recyclable after they are discarded. Therefore, the insulating resin layer of the printed circuit board base material is considered to be changed from a thermosetting resin to a thermoplastic resin.
This facilitates the recycling of waste printed boards. After heating, the resin is separated from the copper foil or metal parts, and each can be recycled and reused.
The solderability coating material on the surface of the printed circuit board, the most traditionally used tin-lead alloy solder, is now banned by the EU RoHS decree, and the substitute is tin, silver or nickel/gold plating.
Electroplating chemical companies in many countries have developed and launched electroless nickel/immersion gold, electroless tin, and electroless silver plating chemicals in the past few years, but similar new materials have not been launched by Chinese suppliers of the same type. PCBA company of HX Technology is committed to using environmentally friendly materials to produce PCB boards.
The traditional production method of printed boards is the subtraction method of copper foil etching to form patterns, which consumes chemical etching solutions and generates a large amount of waste water.
Cleaner inkjet printing wire pattern technology without chemical and water cleaning is a dry production process. The key to this technology is inkjet printers and conductive paste materials. Now some countries have successfully developed nanoscale conductive paste materials, making inkjet printing technology into practical applications.
This is a revolutionary change of printed boards towards cleaner production. China is still lacking micron-scale conductive paste materials that are suitable for use across lines and through holes in printed circuit boards, and nano-scale conductive paste materials are even more invisible.
In clean production, cyanide-free gold electroplating process materials, chemical copper precipitation process materials that do not use harmful formaldehyde as a reducing agent, etc., it's all PCBA suppliers' duty to speed up the development and application of printed board production.
Electronic equipment is developing towards digitalization, and there are higher requirements for the performance of supporting printed boards. At present, there are requirements such as low dielectric constant, low moisture absorption, high temperature resistance, high dimensional stability, etc. The key to meeting these requirements is to use high-performance copper clad laminate materials.
In addition, in order to realize the thinning and high density of printed circuit boards, copper clad laminate materials such as thin fiber cloth and thin copper foil are required.
The key to highlighting the light, thin and flexible characteristics of flexible printed boards is the flexible copper clad laminate material. Many digital electronic devices require the application of high-performance flexible copper clad laminate materials. At present, the direction of improving the performance of flexible copper clad laminates is adhesive-free flexible copper clad laminate materials.