PCB manufacturing solder paste technical requirements
PCB manufacturing solder paste is a key process material which is necessary for reflow soldering processes. The solder paste is a cream solder which is uniformly mixed by an alloy powder and paste flux carrier. The printability and solderability quality of the solder paste directly affect the assembly quality of the SMT.
1. Before solder paste application
A. During solder paste preparation and storage period before printing, store at 2-10 ° C (or at room temperature) for one year (at least 3-6 months), the performance of solder paste should remain unchanged
B.The metal powder and flux in the solder paste are not layered.
C.Low hygroscopicity, low toxicity, odorless, non-corrosive.
2.During solder paste application
A.It is required that the viscosity of the pcb manufacturing solder paste changes little with time. When printing continuously at room temperature, it is required that the solder paste is not easy to dry.
B.Has good de-moldproperty, does not block the template leak when printing continuously
C.Keep the original shape and size after printing, nodrop, good thixotropy (shape retention)
D.After printing keep at room temperature for 12-24h, at least 4h, its performance remains unchanged.
A.During the reflow soldering preheating process, the solder paste collapse deformation is required to be small.
B.The reflow wettablityis good, the solder fly is less, and the minimum amount of solder balls is formed.
C.Good wettabililty performance.
A.The formed solder joints have sufficient strength to ensure that the solder joints will not be damaged due to factors such as power generation and vibration.
B.Post-weld residue has good stability, no corrosiveness, high insulation resistance, easy to clean after welding
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