Current situation of flux development at home and abroad

With the booming development of the electronics industry, the demand for electronic auxiliary materials for electronic assembly and processing: flux is also growing rapidly, and the requirements are also increasing. The quality of flux has an important influence on the quality and reliability of electronic products.

Flux is accompanied by the emergence of electronic manufacturing industry. Early flux rosin as active agent, commonly known as rosin water. Rosin flux has been used in the electronics industry for a long time. When the electronics industry was not developed, rosin was found to be the best of all materials because of the limitations of the characteristics, cleaning and corrosion of parts themselves. Because organic cleaning agents on homework personnel had a greater influence on the healthy body, the industry introduced a water-soluble flux, water-soluble flux with water as a cleaning agent, auxiliary equipment for washing machine, but after cleaning wastewater discharge to the surrounding environment influence without a lot of promotion, as the requirement of environmental protection are increasing, with deionized water as carrier of water flux arises at the historic moment, Water-based flux showed good results compared with alcohol-based flux, especially for plate residues and solderability. The active agents and chemicals in the flux react more chemically in water than in alcohols. Although the price of water-based flux is higher at present, the weldability is improved, the number of flux used is relatively reduced, and the maintenance and cleaning of machinery and equipment are easy. The factory environment is more environmentally friendly and safer. In addition, international resources are increasingly poor, oil prices continue to rise, water-based flux will become the main trend of flux industry development in the future.

Chinese flux flourished in the 1980s, because of its simple production process, low entry threshold, manufacturers like bamboo shoots after a spring rain dig up. Due to their conditions, quality is uneven. Present two polarity division: one is to stand in the development of the brand of large manufacturers, its process mechanization degree is high, complete inspection equipment, rigorous operation procedures, perfect system, technology, quality and the United States, Germany and other foreign brand manufacturers. Customer base for medium and high-end electronic products customers, more national brand enterprises and international famous brands of China factory and OEM factory, the other is some small vendors, rough process, no detection means, without a complete operation system, some completely in the stage of family firms, most of these manufacturers no stable supply chain, materials cheaper order whose young, The product stability is poor, and most of the customers are low-end electronic products such as radios and recorders.

Foreign manufacturers have been established for a long time, mature technology, advanced equipment, strong research and development technical force, high material requirements, high cost, high market price, and occupy a leading position in the international electronic brand enterprises. Its favorable advantages is the first impressions are most lasting, no early domestic flux technology, electronics companies in the absence of more options to import, in use process even though the price is high, but quality did not appear abnormal obviously, moreover flux appear negligible in electronic products, the cost of making electronics seldom go to consider replacement flux suppliers, Therefore, the position of foreign manufacturers in the brand electronic manufacturing industry is consolidated. In 2008, the promulgate and implementation of China's new labor law, the international price of raw materials continues to rise, and the shortage of China's labor market have attracted great attention from all sectors. International well-known brand electronic enterprises have to put manufacturing cost control on the important agenda, which puts forward a test to foreign flux manufacturers. Also virtually to the domestic comprehensive advantage stronger manufacturers to provide more chance.

Opportunities are built on the basis of enterprise strength. In the 1980s and 1990s, as auxiliary materials, flux is generally not clear about the strength of such suppliers, and there is no management and audit plan. Quite a part of the management of electronic manufacturers of flux manufacturers are left in the impression of flux sales staff and after-sales engineering staff in the description of the hype, should be a slogan: blow it! This is the stage for your wonderful life. On July 1, 2006, the European Union officially issued the implementation of the "Waste power Electronic Equipment Directive (WEEE)" and "The Prohibition of the use of certain toxic and hazardous substances in power electronic Equipment directive (ROHS)", which has been discussed for 5 years. To compare the properties of tin-lead alloy solder according to JIS Z3198 (Test Method standard for Lead-free Solder) and related standards, Consider Sn-Cu, Sn-Ag, Sn-Ag-Cu lead - free solder (including trace quaternion alloy derived from this) which is suitable for solution point, electrical properties, mechanical properties, wetting and spreading properties and other conditions. The introduction of lead-free solder has brought a revolution in flux technology, solved the high humidity welding, made up for the poor fluidity of lead-free solder and other defects, but brought different degrees of ICT probe testing difficult problem. The delivery time makes electronic manufacturers create a race for flux manufacturers. The first one who can meet the requirements of lead-free welding with low residual and low viscosity after welding, and solve the problem of ICT testing, will get the introduction.

Promote lead-free process, the eu market and customs puts forward strict requirements on product manufacturing chain, electronic manufacturers to not too concerned about flux manufacturers are also included in the category of audit, the flux of the supply chain, process technology, testing, have put forward specific requirements, for the process simple, imperfect system of small and medium-sized manufacturers lost numerous opportunities of competition, Development step is strong, but for the country with domestic brand manufacturers and foreign manufacturers is a new shuffling opportunity.

With the implementation of lead-free process, some problems have been raised, especially its implementation cost. The electronics industry has turned its attention to the PCB circuit board with high cost, which has brought about the change of PCB coating method. The main methods of lead-free PCB welding plate coating are:

1. Sn/Pb Hot Air Leveling (HASL) replaced by Lead-free solder alloy

This coating has good solderability, but poor flatness, and is difficult to be used for narrow spacing and small components.

2. Electroless Ni and Dip Plating (ENIG)

The coating has good weldability, but there are "gold brittle" and "black pad" phenomenon

3. Silver leaching process (I-AG)

It is a low cost alternative to electroless Ni plating and immersion gold plating (ENIG). But it is necessary to accurately control (I-AG) chemical formula, thickness, surface flatness, and organic elements distribution within the silver layer.

4. Tin immersion process (I-SN)

I-snee is cheaper, and the wettability of the new plate is better, but after storage for a period of time, or after multiple reflow, the wettability decreases quickly, and even cannot withstand a reflow welding before wave soldering, the process is poor.

5. Cu surface coated with OSP

Good solderability, electrical conductivity, flat, but short shelf life, can not reflux many times, double panel reflux process should be paid attention to, and the application of OSP material suitable for lead free high temperature.

In the above several lead-free PCB pad coating, the industry has focused on the lowest price OSP coating process, and gradually promote. It also introduces weldability problems. The following two figures are the price of lead-free PCB solder plate coating and the comparison of the expansion rate:

Comparison of lead-free PCB pad coating cost comparison of lead-free PCB pad coating expansion rate

Cu surface coating of OSP process directly brought again with flux manufacturing technology innovation, although the OSP coating process is the most cheap but its weldability is also relative to the worst, the importance of flux in the welding process is more prominent, the adjustment of the manufacturers are actively, research and development of new products in order to achieve good welding purpose. Domestic manufacturers with r&d strength in new product adjustment have the advantages of short adjustment cycle and timely service. When discussing with the senior management of a foreign brand manufacturer, he said with great emotion: when they were still going through the process, our newly adjusted products had been confirmed in batches in the customer's production line.  When the dust settled on OSP pre-coated welding, the draft POHS directive of the Norwegian Product Regulations was proposed by the Norwegian Pollution Control Authority (SFT) at the end of May 2007, and the final version is expected to be implemented in 2008. POHS requires that in addition to lead and cadmium in ROHS, 16 new controlled substances are added. In order to meet the environmental requirements of POHS and halogen-related compounds, international well-known brand enterprises shall comply with IEC 61249-2-21: For printed Boards and other materials for interconnect structures, part 2-21 of coated and uncoated E glass fiber reinforced halogen-free flame retardant (vertical combustion test) epoxy resin copper-coated plates, the halogen-free control requirements of Cl < 900PPM, Br < 900PPM and Cl+Br < 1500PPM are proposed for upstream related enterprises. Conforming to the advance of international halogenation, Tongfang has developed environmental halogen-free flux AATF9100 and AATF-9200, which are fluorine, chlorine and bromine free. According to the analysis of industry insiders, the implementation of halogen-free will lead to an increase in material cost of about 35%-500%. Whether the direct control of halogens (F, CL, Br, I) can replace the control of various halogen compounds needs to be further determined by international well-known brand enterprises. The concept of environmental protection continues to deepen, domestic comprehensive strength of flux manufacturers will lead the field of electronic welding.