How to select the material for the needle exclusion:
 

Of all metal elements, metal copper is the best in all metal elements; silver (about 1.06 times of copper) > copper > gold (about.077 times of copper), but gold and silver are generally used only in the connector plating material, which can reduce the contact impedance and increase the antioxidant effect of the outer white, while the copper metal is low in price. And the electrical conductivity is good, so in the wire and cable all use pure copper as the electric power, wire, information transmission widely used, but also in the electronic connector industry for the best purchase material pure copper electrical conductivity is good, but its mechanical strength and heat resistance, insufficient to reach the connector industry standard, so it needs Adding some alloy elements to improve their mechanical strength and heat resistance, the electrical conductivity of pure copper is good, but its mechanical strength and heat resistance are not sufficient to meet the requirements of the electronic connector. Therefore, the alloy elements must be added to improve the mechanical strength and heat resistance, but as the addition of metal itself has a specific size of the atom, it will be added to the pure. In copper, it causes the difference between atoms to distort the arrangement of copper atoms, resulting in attenuation or obstruction in the process of transmission. Common on the market: brass (Cu-Zn); brass (Cu-Sn); foreign white alloy (CU-Ni); but its mechanical strength and heat resistance are better than pure copper.
 

The plastic material of the needle row and row of the mother:
The commonly used engineering plastics for needle removal are: LCP, NYLON, PBT.
LCP
With small linear expansion coefficient, low injection molding shrinkage and outstanding modulus of elasticity and modulus of elasticity and excellent heat resistance, it has high load deformation temperature, some can reach more than 340 degrees, LCP also has good chemical resistance and gas tightness, so the general connector is especially the first choice of LCP for SMT.

NYLON
Low cost, high tensile strength, outstanding wear resistance and slippery, good fluidity, good for thin-walled molding, but the shrinkage is serious, easy to produce hair, before forming strict bake, in order to prevent the production of hydrolysis, general connector especially DIP mostly use NYLON material

PBT
Low cost, high strength, friction resistance, but poor formability, severe shrinkage, due to the low melting temperature, over the wave soldering will produce plastic melting phenomenon.