Rotating Disk Centrifugal Atomization Equipment And Technology Of Preparation Of Spherical Solder Powder

Surface Mount Technology (SMT) has been applied abroad in electronic industry. The fine powders of the solder alloy are one of the key materials in the SMT, the shape is spherical, the distribution of the particle size is uniform, the low content of oxygen and predominant antioxidant. We have designed and developed a set of acentric atomizing equipment with the base theory of acentric atomizing and the base characteristic of the alloy. The paper studies systematic the production technology and process of the solder alloy fine powder in the equipment, including the physics parameter and rotate spdeed of the key part of acentric set-turnplate, the atomizing over-heat temperature and flux of melt alloy, the atomizing medium and so on.The result of research indicate: (1)The shape, diameter and rotate speed of turnplate is the core in whole acentric system, is the key factor that impact granularity and distributing of solder powder. The prime turnplate shap is plane, and the propriety parameter of diameter is 40～60mm and rotate speed for 30000～40000r/min. (2) Except insure the melt alloy fluxion smoothly to enhance atomizing efficiency, the temperature can also alter characteristic of melt alloy and influence shape, granularity and distributing of atomizing powder. The prime over-heat temperature is 40～90°C, the flux is 1.2～2.2kg/min, and the powder output of 25μm～45μm thereinto is 20～36 kg/h.(3) The powder with the lowest oxygen content and good spherical shape was atomize with nitrogen.The oxygen content less 50ppm in atomize powder , and less 100ppm after filter with sifter;the non-finite powder less or equal 5%.The enlarge experimentation validate:the solder powder which was made with the acentric set and the prime technology parameter can satisfy the SMT.The target of technology and economy excel or come up to the powder which was made of ultrasonic atomization and gas atomization. Furthermore, the set adopt PLC in control system which can carry out control automatically or semiautomatically to melt temperature, atomization temperature, the atomization pressure and ambience, the flux of melt alloy with good adjustability. Further more, the set can note and reflection the whole atomization course accurately. There is no three wastes (waste gas, waste water and industrial residue) almostly and noise was lower far from the national standard in the whole manufacture which has good characteristic such as economize on energy, protect environmental and high efficiency in yield.