In the industrial electroplating field, **electroless nickel plating lines** are core automated equipment used for electroless nickel plating of metallic or non-metallic substrates (such as PCBs, automotive components, aerospace structural parts, etc.). Their core principle relies on an **autocatalytic redox reaction**, which reduces nickel ions (Ni²⁺) to metallic nickel (Ni) and deposits it uniformly on the substrate surface without the need for an external power supply. This process forms a nickel alloy coating (typically nickel-phosphorus alloy, where phosphorus content determines the coating performance) with high hardness, corrosion resistance, and wear resistance. An electroless nickel plating line is not a single piece of equipment, but a continuous production line composed of a "pretreatment unit → core electroless nickel plating unit → post-treatment unit" and supporting systems. It is widely used in industries such as electronics, automotive, machinery, and precision manufacturing.