The cohesion of tin-lead solder is even greater than that of water, making solder sphere, so as to minimize its surface area (in the same volume, the sphere has the smallest surface area compared with other geometric shapes to meet the needs of the lowest energy state). The effect of flux is similar to that of cleaner on greased metal plate. In addition, the surface tension is highly dependent on the cleanliness and temperature of the surface. Only when the adhesion energy is much greater than the surface energy (cohesion), the ideal tin staining occurs.
The intermetallic bonds between copper and tin form grains. The shape and size of grains depend on the duration and strength of temperature during soldering. Less heat during soldering can form fine crystalline structure, forming excellent soldering joints with the best strength. Long reaction time, whether due to long soldering time, high temperature or both, will lead to rough crystalline structure, which is gravel and brittle.
Welcome to use Printed Board Assembly service from Linke Electronics,we are an expert in this field.
Our Company is UL,ISO9001,ROHS and GJB9001B certified.
Packing and Shipping:
1. How to Get a quotation?
For PCBs,pls send us the Gerber File.For PCBA,pls send us the Gerber file and BOM(Bill of Materials)
2. What is the MOQ?
No MOQ.1 pcs is ok.
3.What is the lead time?
For PCB orders,the lead time is 2 to 10 days.For PCBA orders,the lead time will be 15 to 30 days.
4.Will the boards be tested before shippment?
Yes,all PCBs will be tested by Flying Probe or E-test.For PCBA,we will have AOI,X-ray,and functional test