Summary of Core Equipment for PCB Wet Process: Analysis of Functions in Each Stage
The PCB wet process is a key link in completing circuit processing relying on liquid chemicals and special equipment, directly affecting the precision and reliability of circuit boards. The following disassembles the names and core functions of core machines in each stage of the wet process to help quickly grasp the core value of the equipment.
1. Pre-treatment Stage: Board Scrubber
The board scrubber is the core equipment for pre-treatment. Its main function is to remove oxides, oil stains and dust from the surface of the PCB substrate, while improving the surface roughness of the substrate. It is divided into physical board scrubbers and chemical board scrubbers. The physical type removes dirt through brush grinding and high-pressure water washing, while the chemical type uses micro-etching solution for cleaning and roughening. Both can lay a solid adhesion foundation for subsequent dry film coating and electroplating processes, avoiding delamination and peeling problems.
2. Pattern Transfer Stage: Developer Machine, Stripper Machine
The developer machine is responsible for accurately replicating circuit patterns onto the substrate. It dissolves the photoresist in unexposed areas by spraying developer solution to expose the copper foil patterns to be etched or electroplated, ensuring the precision of circuit formation. The stripper machine is used to remove residual photoresist after etching and electroplating. Divided into acid and alkaline types according to the photoresist type, it removes excess glue layers to expose the final circuit.
The etching machine is the core of circuit formation. It dissolves unprotected copper foil with chemical etching solution to form preset circuits. The mainstream type is spray-type, featuring high efficiency and good uniformity. The PTH plating line (PTH Plating Line) is used for hole wall metallization, depositing a copper layer on the inner wall of drilled holes through multi-station processing to realize circuit conduction of multi-layer PCBs. The electroplating machine can thicken the copper layer to improve circuit conductivity, and also derive gold-plating and tin-plating models to meet different protection needs.
The OSP coating machine applies a protective film on the copper surface to prevent oxidation and ensure solderability. The washing machine removes residual chemicals from each process to avoid affecting subsequent processing; the dryer machine removes moisture from the substrate to prevent oxidation and poor plating. Both are key auxiliary equipment to ensure process stability.
