For Power connectors often withstanding high current transmission and have more serious working environment in all types of connectors, so it is worthy for us to discuss the application problems of the power connector.  Below are four common power connector application problems, and analyzed one by one:

First, what are the different plating of power connector according to different applications use?

      When power Connector choose plating, major consider its working environment, divided into three cases:

1)     For general applications, tin is the most common, because tin is cheaper, but relatively soft texture, in order to ensure good contact, requiring a higher contact force (at least 100 grams), mating cycles is generally less, can only do simple protective and anti-corrosion, operating temperature is relatively low, tin-plated brass or bronze operating temperature can up to 110 ℃, tin-plated steel can up to 190 ℃. For more mating cycles, generally requires gold plating. For higher operating temperatures, we need other plating, such as nickel-plated copper application  up to 340 ℃, nickel-plated brass or bronze up to 250 ℃.

2)      For high reliability requirements of small-signal applications that require a small contact force application ,  generally with gold plating, meanwhile gold’s corrosion resistance is also very prominent. Nickel is commonly plate bottom of gold, most nickel-plated steel contacts (must first plate copper). Palladium’s conductivity is poor than gold’s, mostly used instead of gold plating in some limited scope. Current price of gold continued to rise, palladium-nickel alloy products is also increasing. Silver-plated contacts have very good conductivity, but silver is easily oxidized, so only choose use in exceptional circumstances.

3)  Due to corrosion, improve electrical connection performance, reduce temperature and other considerations, the current connector basically need to be plated. We have seen some large currents special applications without do plating treatment, but it was very rare.

Second, the power connectors generally do what tests?
In addition to connectors’ common tests, such as contact resistance, insulation resistance, voltage resistance, solderability , mating cycles,shaken, the insertion / pull-out force, environmental testing and so on, the power connector test is quite special: temperature rise and current relationship, hot-swap (if required). Large different test requirement with signal connector, signal connector, especially high-speed signal connectors, in addition to common tests, will be more concerned about the performance in signal integrity.
   Third, why the pin do not absorb tin? How to deal with?
If you exclude the soldering procedure issues, such as solder temperature, suitable flux, solder time, pin do not absorb tin be caused by the contact surface oxidation or dirty, pay attention to use as soon as after opening the package, keep storage environment dry. There is bad product plating and substrate exposed, also can cause the pin do not absorb tin.

Should determine what is causing first. If the process issues, it is necessary to improve the process, for example, choose the appropriate flux, set corresponded solder temperature, adjust the furnace time (reflow soldering), or chain speed (wave soldering) and so on; if the pins are dirty, need do targeted cleaning; if it is oxidized issue (basically no tin absorbed, or even if have tin absorbed, there is no infiltration status) ,it is more trouble, and now there is no good reducing agent to remove the oxide layer, you may consider discard process, in practice, in the case of small quantities, some companies use to scrape the oxide layer before soldering again, but the reliability of this method has not been verified.

Fourth, have automatic shutdown issue in the complete machine test, which was confirmed that the first-line to board connector is bad contact in this batch, and now vendors have brought improved products, how to test whether this new batch have improved or not? What are standards?

In this regard, experts suggest, first identify what the root reason, must find out the real reason, not only in view of the phenomenon. For example, the first is disconnect the wire, complete testing and evaluate the problem is caused by the connector, or by wire, or by crimping, check step by step. Then check whether the suppliers have already improved, and check whether the improvements are reasonable and effective.
    Testing must be targeted, also can tighten test conditions. For example, to the new sample, oxidation, it is not only to check the appearance, but also to re-test reliability. For example, Tyco Electronics have a complete test file of reliability for their products, and then assembled, and then make the whole test.