When hot liquid solder dissolves and penetrates to the surface of the welded metal, it is called metal tin or the metal is tin-stained. The molecules of the mixture of solder and copper form a new part .It is copper and tin of solder alloy. This medium action is called dipping tin, which forms an intermolecular bond between each part to form a metal alloy co-compound. Good intermolecular bond formation is the core of welding process.It determines the strength and quality of welding joint. Only the surface of copper is not contaminated, no oxide film formed by exposure to air can be stained with tin, and the solder and the working surface need to reach an appropriate temperature.
Everyone is familiar with the surface tension of water, which keeps cold water droplets on greased metal plates in the shape of a ball, because in this case the adhesion of the liquid on the solid surface tends to diffuse less than its cohesion. Wash with warm water and detergent to reduce the surface tension, water will infiltrate the grease coated metal sheet to form a thin layer of flow, if the adhesion is greater than cohesion will happen this kind of thing.(Printed Circuit Assembly)
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