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In the rapidly developing modern electronics manufacturing industry, the empty pcb board plays a crucial role as one of the core components of electronic products. Empty pcb board is not only a bridge connecting electronic components and final products, but also the basis for realizing the functions of electronic devices. The purpose of this article is to provide an in-depth analysis of the definition, classification, and production process of empty pcb boards.
What is the empty pcb board?
Empty pcb board is a printed circuit board that is not processed in any way, is not covered with a protective layer and does not have any electronic components installed. Empty pcb board is the backbone of a traditional circuit board that directs electrical current through appropriate paths and is used in most computing and electronic devices. Empty pcb boards offer engineers and designers a wide range of design possibilities due to their basic nature, flexibility and customizability.
The classification of empty pcb board
Based on the number of layers and structure of the board, bare pcb board can be divided into three main types: single-sided boards, double-sided boards and multilayer boards.
Single-Panel
Single-panel is the simplest type of bare-board circuit board, with only one side copper-clad and only one side chemically etched. Single-panel is usually used for simple circuits only. Due to its simple structure, single-panel is often used to implement simpler circuits such as low-frequency circuits, power supply circuits, and so on. Single panels are less expensive to manufacture and have limited circuit complexity.
Double-sided boards
Dual-sided panels have circuit patterns printed on both sides of the substrate and are electrically connected on both sides through metallized holes, which do not affect each other. This structure allows dual-sided panels to carry more complex circuits and is suitable for application scenarios such as high-frequency circuits and digital circuits.Although the manufacturing cost of dual-side panels is higher than that of single-side panels, their circuit density and performance are both improved over single-side panels.
Multi-layer boards
Multilayer boards are made of several single or double-sided boards pressed together, and multilayer boards usually have more than four layers. With extremely high circuit density and excellent performance, multilayer boards exhibit good electromagnetic shielding and heat dissipation properties due to their unique structural advantages. With the continuous progress of technology, multilayer boards have become smaller and smaller, and can be more naturally integrated into a variety of high-end electronic equipment,communications equipment and other space-constrained application scenarios. However, in contrast, the manufacturing cost of multilayer boards is also relatively high, and the production process is more complex.
The production process of empty pcb board
The production process of empty pcb board includes many steps such as opening, drilling, copper sinking, plating, etching, stamping, cutting, and testing. The following is a brief description of the key steps:
Material Preparation
Raw material preparation: The selected raw materials mainly include insulating substrates (e.g. fiberglass cloth, epoxy resin, etc.) and copper foil. These materials need to be strictly screened and pre-treated to ensure product quality.
Cutting: According to the requirements of the engineering data, large sheets are cut into the required small production boards. This step usually includes processes such as cutting, curiuming and edge grinding to ensure that the size and shape of the sheet meets the requirements.
Drilling
Positioning and drilling: For double-sided and multilayer boards, it is necessary to use a drilling machine to drill metallized holes in the boards according to the hole position information in the design documents to realize the electrical connection between different circuit layers. The drilling process requires precise control of the hole size and positional accuracy. Inspection and repair are required after drilling to ensure the accuracy of the hole positions and the quality of the hole walls.
Copper immersion
Surface treatment: The surface of the plate is treated by grinding and drying processes to improve the adhesion of the copper layer.
Copper deposition: A thin layer of copper is deposited on the surface of the plate to form a conductive layer. This process usually includes automatic copper deposition lines, copper thickening and other processes.
Graphics Transfer
Graphics production: the use of film and other tools to produce circuit board graphics, and through the exposure, developing and other processes to transfer the graphics to the board, this process requires precise control of the exposure time, developing temperature and other parameters to ensure the accuracy of the graphics transfer.
Inspection:Inspection of the board after the transfer of graphics to ensure the accuracy and integrity of the graphics.
Graphic Plating
Pre-Plating:Includes processes such as degreasing, washing, and micro-etching to clean the surface of the board and improve its plating performance.
Plating:Plating metal layers such as copper and tin on the board surface to enhance the conductivity and solderability of the board. The plating process needs to control the composition of the plating solution, temperature, current density and other parameters. Cleaning and inspection are required after plating.
Depatterned film
Decoating:Removal of unnecessary layers such as protective film formed during the plating process to allow for subsequent processes.
Etching
A chemical etchant is used to remove copper foil that is not protected by graphics (non-wiring areas) to form a circuit pattern. The etching process requires strict control of the etching rate and concentration of the etchant to avoid over- or under-etching.
Green Oil (Soldermask Production)
Green Oil Coating:A layer of green oil (soldermask) is applied to the surface of the board to protect the wiring and prevent short circuits during the soldering process.
Curing and Inspection:Curing and inspection of the coated green oil to ensure its quality and adhesion.
Character
Character Printing:Printing characters or logos on the circuit boards to facilitate installation and commissioning.
Gold plating (if required)
Gold plating treatment:Plating a layer of gold or nickel on key parts such as connectors to improve their conductivity and corrosion resistance.
Molding
Stamping or Gong Cutting:Process the circuit boards into the shape and size required by the customer by means of mold stamping or CNC gong machines.
Testing
Flying probe test
Performance Test:Using equipment such as test racks or flying probe testers to conduct performance tests on the circuit boards to ensure their electrical performance and reliability.
AOI Inspection
Appearance Inspection:The boards are visually inspected using AOI (Automated Optical Inspection System) to detect any visible defects or problems.