Environmental protection PCB technology

Since the eu formally in December 2003 after "lead-free" legislation, the global electronic has great impact, in July 2006, the European Union WEEE directive about scrap electrical and electronics equipment, electrical equipment on restricting certain pollution substances in the ROHS directive and the Japanese association for the advancement of electronics industry (JEIDA) and the national electrical manufacturers association (NEMl) about the lead, the halogen electronic packaging industry has come into effect, the market of electronic products not contain lead, mercury, cadmium, hexavalent chromium, and restrict the use of polymeric brominated diphenyl or brominated flame retardants, PBB, PBDE harmful substances, such as this will impact of the global supply chain operations, including PCB industry and the development of relevant industries.My company to research environmental protection PCB products since 1999, and became one of the earliest recognized global green partner manufacturers Japan panasonic, and environmental protection and is now 99% PCB products are resonant.In this paper, from the raw material control, the choice of lead-free process and control and SMT electronic encapsulation after three aspects, comprehensively expounds how the next generation of PCB products to meet the increasingly stringent environmental requirements.

The selection and control of raw materials
As is known to all, in the PCB industry, mercury, cadmium and hexavalent chromium are almost don't have to, or in addition to containing trace, in the process of wet process will not be deliberate use of PCB manufacturers, so in the choice of raw materials and process, as long as considering the lead Pb and halogen don't overweight can conform to the basic requirements of environmental protection, metal processing is in be lead-free PCB surface (< 0.1% Pb), the traditional PCB and SMT industry, due to the extensive use of lead, tin alloy, such as HAL, solder paste, etc.Lead is a heavy metal elements, is widely distributed in nature, is the three elements of radioactive uranium and thorium, the end product of the decay of actinium, once the body of the lead intake more than its saturation concentration, can appear the symptom such as anemia, calcium deficiency, weakened immunity.Why do you want to lead-free solder?Leaded solder harmful: lead in solders for the soldering is 1% of the total usage weak (30000/5 million tons), and have widely spread the possibility of difficult to fully recovery.Due to environmental pollution, anxiety, such as lead poisoning effect on human body.In the PCB industry, halogen (fluorine, chlorine Cl, Br Br, 1 F) application mainly on the plate and ink.

material choosing
PCB processing eventually formed on the finished product, mainly includes three types of material: plate, surface processing (metal) layer and ink.1.1.1 plate regular plank FR - 4, CEM - 3, because contain a large number of brominated epoxy resin, such as four bromine bisphenol a, polybrominated biphenyls (PCBS), polybrominated diphenyl ether, etc., in the process of combustion, emit high toxic substances, such as dioxin (TCDO), such as benzene, furan, once the intake will not be able to discharge by human body, greatly threatening the human health.So the PCB must be halogen-free copper clad industry base material chlorine (Cl, Br Br is less than 0.09% respectively), phosphorus (P) epoxy resin instead of brominated epoxy resin, with nitrogen (N) phenol to replace the traditional dicyandiamide curing agent.
In addition, the environmental protection plate also has the strong heat resistance, able to lead-free SMT engineering under 260 degrees high temperature for many times, do not change color, stratification, deformation and bending.

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