PCB Blogger-China PCB Factory,HOYOGO

  The ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) technology, is the addition of a layer of palladium between nickel and gold. In the deposition reaction of gold replacement, the electroless palladium layer protects the nickel layer from excessive corrosion by the replacement gold and is well prepared for immersion gold process.     ENEPIG process: Degreasing ---- Microetch ---- Pickling ---- Pre-dip -----Activating Palladium ---- Chemical Nickel (Reduction) ---- Chemical Palladium (Reduction) ---- Chemical Gold (Replacement)     ENEPIG technology is applied to the surface treatment of package substrates. In the ENEPIG process, by controlling the palladium on the nickel layer and controlling the ENIG, accurate deposition thickness and uniformity of the gold layer are obtained to achieve a good contact surface. Through the comparison of wire bonding ability, solderability and aging resistance between ENEPIG pad and electroplated nickel gold pad, it is verified that

       With the gradual miniaturization of electronic products, the corresponding PCB size is also slowly decreasing.  If you want to mount enough electronic materials in a limited space, sometimes it is not enough to rely on single-sided placement, and it needs to be achieved by double-sided placement.     Double-sided placement, as the name implies, means that both sides of the PCB need to be mounted.   This technology requires placement one side of the PCB before placing the other side of the PCB.  This placement method can not only utilize the limited space of the PCB, but also ensure the aesthetics and functionality of the PCB.   So what do you need to pay attention to when doing double-sided placement?     1. Electronic components with high heat resistance are mounted first. Because some electronic components cannot withstand two high-temperature soldering, the components that are not resistant to high temperature are usually mounted on the second side when re-placement, so that

       The tombstoning phenomenon refers to the phenomenon that one end of the electronic component does not touch the pad and stands obliquely upwards or the contact pad is upright during PCBA processing. So how to avoid this phenomenon?       1.  W arm-up  P eriod We should correctly set the technology parameters during preheating.  When the preheating temperature is set low and the preheating time is set short, the probability of melting the solder paste at both ends of the component at the same time will greatly increase, resulting in unbalanced tension at both ends, thus forming a "tombstoning".     2. Pad  S ize When designing chip resistor and capacitor pads, the overall symmetry should be strictly maintained, that is, the shape and size of the pad pattern should be exactly the same to ensure that the resultant force acting on the solder joints on the component is zero when the solder paste melts, so that  f orm ing  ideal solder joints.   For small thin chip component