Main features of lead-free soldering and solder joints
(1) Main features of lead-free soldering
(A) The high temperature and melting point are about 34 ° C higher than the conventional lead eutectic solder.
(B) The surface tension is large and the wettability is poor.
(C) The process window is small and the quality control is difficult.
(2) Characteristics of lead-free solder joints
(A) Poor wettability and poor spreadability.
(B) The lead-free solder joint has a rough appearance. Traditional inspection standards and AOI need to be upgraded.
(C) There are many air holes in the lead-free solder joints. Especially when the lead solder joints are mixed with the lead-free solder, the lead solder on the solder joints (balls) is first melted, covering the pads, and the flux is not discharged, resulting in pores. However, the pores do not affect the mechanical strength.
(D) Many defects - the self-positioning effect is weakened due to poor wettability.
Lead-free solder joints have a rough appearance, many pores, a large wetting angle, and no half-moon shape. Since the appearance of lead-free solder joints is significantly different from that of lead-free solder joints, if it is measured by the original lead inspection standard, it can even be considered as Unqualified, with the deepening and development of lead-free technology, due to the improvement of flux and the progress of the process, the rough appearance of lead-free solder joints has been improved.
Medical Training Media Processor
Medical Training Media Processor,Medical Video Recorder,Video Conferencing Encoders,Medical Signal Recording Encoders
SZ REACH TECH,.CO LTD , https://www.szreachtech.com