The hottest is to improve the application of lead-

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According to the European Union RoHS directive - improve the application level of lead-free process technology

lead is very harmful to human brain, nervous system, liver, kidney, etc. if lead in lead tin solder seeps into the soil, it will pollute groundwater sources, and it is likely to cause other pollution in the process of separating lead. How to effectively limit the use of lead has become an important issue that the modern electronic industry must face

according to the requirements of RoHS directive, traditional electronic parts assembly, SMT Soldering, wave soldering, tin lead surface treatment and other processes will face major changes. Philips, Intel, NEC and other major international manufacturers have set lead-free schedules for their products or parts, and require the cooperation of suppliers. For the domestic electronics industry, which plays an important role in the global OEM of 3C products, it is bound to face major challenges

for the industry, the lead-free process has significantly changed the existing production mode, but at this stage, it seems that there is still a lack of relatively mature technology and recognized standards and norms, which leads to the industry unable to smoothly introduce the relevant process, and then unable to produce effectively, indirectly threatening its future survival. At present, the lead-free effect of passive components such as components and nano reinforced plastics in China is relatively significant, but the active components are controlled by large foreign manufacturers, resulting in the slow progress of introducing some lead-free components

at this stage, the European Union focuses on key areas, and the RoHS directive does not announce the standard test method of lead compounds, resulting in the difference in the test values of laboratories and verification institutions. Our goal is to obtain 6 times the thermal conductivity of fat trees, which is quite large, and the product test report cannot be trusted

at present, there are no more than six kinds of materials for PCB substrates used in lead-free manufacturing process: gold plated plate, OSP plate, silver plate, gold plate, tin plate, tin silver copper spray tin plate and other six kinds of plates

gold plated plate is the most stable and suitable for lead-free process among all plates at present, especially in some electronic products with high unit price or high reliability, it is recommended to use this plate as the base material, but its cost is also the highest among all plates. Using OSP board, after high temperature heating, the protective film pre coated on the pad is bound to be damaged, resulting in the reduction of solderability, especially when the substrate is reflowed twice. Therefore, if another dip process is required in the process, the dip end will face the challenge of welding

silver plate, although "silver" itself has strong mobility, which leads to the occurrence of electric leakage, today's "silver immersion plating" is not a simple metal silver in the past, but an "organic silver" co plated with organic matter. Therefore, it has been able to meet the requirements of the future lead-free process, and its solderability life is longer than that of OSP plate. The biggest problem of this kind of substrate is the problem of "blackpad". Therefore, many large manufacturers do not agree to use it in the lead-free process. For example, HP stipulates that all HP products cannot use this kind of substrate. Dell is also gb/t 14800 (1) 993 "test method for bursting strength of geotextiles" (equivalent to ASTM D 3787) gb/t 13763 (1) 992 "test method for trapezoidal tearing strength of geotextiles"

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