Printed circuit board production process. Almost every kind of electronic equipment, from electronic watches, calculators, to computers, communication electronic equipment, military weapon systems, as long as there are electronic components such as integrated circuits, printed boards must be used for electrical interconnection between them

1 Overview

Almost every kind of electronic equipment, from electronic watches, calculators, to computers, communication electronic equipment, military weapon systems, as long as there are electronic components such as integrated circuits, printed boards must be used for electrical interconnection between them . In the research process of larger electronic products, the basic success factors are the design, documentation and manufacturing of the product's printed board. The design and manufacturing quality of printed boards directly affects the quality and cost of the entire product, and even leads to the success or failure of commercial competition.

  One. The printed circuit provides the following functions in electronic equipment:

　　 Provide mechanical support for the fixing and assembly of various electronic components such as integrated circuits.

　　 Realize wiring and electrical connection or electrical insulation between various electronic components such as integrated circuits.

　　Provide the required electrical characteristics, such as characteristic impedance.

　　 Provide solder mask graphics for automatic soldering, and provide identification characters and graphics for component insertion, inspection, and maintenance.

　　 Two. Some basic terms related to printed boards are as follows:

　　 On the insulating base material, according to the predetermined design, the printed circuit, the printed element or the conductive pattern formed by the combination of the two are made, which is called the printed circuit.

　　 On an insulating substrate, a conductive pattern that provides electrical connections between components and devices is called a printed circuit. It does not include printed components.

　　 Printed circuits or printed circuit finished boards are called printed circuit boards or printed circuit boards, also known as printed boards.

　　 printed boards can be divided into two categories according to whether the substrate used is rigid or flexible: rigid printed boards and flexible printed boards. According to the number of layers of conductor patterns, it can be divided into single-sided, double-sided and multilayer printed boards.

　　 A printed board where the entire outer surface of the conductor pattern and the surface of the substrate are on the same plane is called a flat printed board.

　　For the terms and definitions of printed circuit boards, please refer to the national standard GB/T2036-94 "Printed Circuit Terminology" for details.

After electronic equipment adopts printed boards, due to the consistency of similar printed boards, manual wiring errors can be avoided, and electronic components can be automatically inserted or mounted, automatic soldering, and automatic detection, ensuring the quality of electronic equipment , Improve labor productivity, reduce costs, and facilitate maintenance.

　　 Printed boards have developed from single-layer to double-sided, multilayer and flexible, and still maintain their respective development trends. Due to the continuous development in the direction of high precision, high density and high reliability, continuous reduction in size, cost reduction, and performance improvement, the printed board will still maintain a strong vitality in the future development of electronic equipment. three. A sign of the technical level of printed boards:

The technical level of printed boards is a sign of double-sided and multi-hole metallized printed boards: it is a double-sided metallized printed board produced in large quantities, two at the intersection of 2.50 or 2.54mm standard grid Between the pads, the number of wires that can be laid as a sign.

　　 A wire is laid between the two pads. It is a low-density printed board with a wire width greater than 0.3mm. Two wires are laid between the two pads, which is a medium-density printed board with a wire width of about 0.2mm. Three wires are arranged between the two pads, which is a high-density printed board with a wire width of about 0.1-0.15mm. Arrange four wires between the two pads, which can be regarded as an ultra-high-density printed board with a line width of 0.05-0.08mm.