Pogo pin generally includes three parts, plungers, springs and barrels.
For plunger, the common material is Becu or SK. For these two materials, both have advantages and disadvantages. The continuity of Becu is good, but the hardness is not enough. SK has high hardness, but easy to rust.
Spring is also very important for Pogo Pin. Right now there are SUS and SWP. Now that more and more products are PB free. The direct result is that BGA solder balls become soft or hard. In the beginning of the testing process, you can found the pass rate is high. However, after changing the solder balls or the pin material, the pass rate is low. And the spring pressure is very important.
The test environment has strict requirement of spring material. The high and low temperature test directly affect the working life of the probe.
For barrel, the most common material is PB material. The main causes of low yield may be due to the impedance of the probe during the test becomes large caused. Variable impedance is large, mostly due to the needle during the test needle wear, damage coating, as well as tin-needle caused.