Product assembly process 1. Formulate the basic principles and raw data of assembly line process.
Reasonable arrangement of assembly sequence, minimizing fitter's assembly workload, shortening assembly cycle, improving assembly efficiency and ensuring product quality of assembly line are the basic principles for formulating assembly line technology. The original materials for making the assembly process are the technical standards for product acceptance, production procedures and existing production conditions.
2. The content of assembly line process regulations
Analyze the assembly drawing of assembly line products, divide the assembly units, and determine the assembly sequence and method of each component; Determine the assembly technical requirements, inspection methods and inspection tools of each process on the assembly line; Select and design tools, fixtures and special equipment needed in the assembly process; Determine the transportation methods and means of parts in the assembly line assembly process; Determine the time quota of assembly line assembly.
3. Steps to formulate assembly line process regulations
Firstly, analyze the original data of products on the assembly line; Determine the assembly mode and organization form of the assembly line; Dividing assembly units; Determine the assembly sequence; Dividing the assembly process; Compile assembly process documents; Formulate product inspection and testing specifications.
Matters needing attention
1. Ensure product quality; Prolong the service life of the product.
2. Arrange the assembly sequence and process reasonably, minimize manual labor and meet the requirements of assembly cycle; Improve assembly efficiency.
3. Minimize the assembly floor space and improve the productivity per unit area.
4. Try to reduce the assembly cost. The process of assembly, debugging and testing to make it a qualified product.
Electronic product assembly steps
1. assembly features
Electronic products are technology-intensive products, and the main features of assembled electronic products are:
(1) assembly work is composed of many basic technologies. Such as component screening and lead forming technology; Wire processing technology; Welding technology; Installation technology; Quality inspection technology, etc.
(2) In many cases, it is difficult to quantitatively analyze the quality of assembly work. For example, the quality of welding is usually judged by visual inspection, and the assembly quality of scale plate and knob is mostly recognized by touch.
(3) Personnel engaged in assembly work must undergo training and selection, and are not allowed to take up their posts casually.
2. Assembly technical requirements
(1) The marking direction of the component shall meet the requirements of the drawings, and the marking on the component shall be clearly visible after installation. If the direction is not indicated in the assembly drawing, the marks should be easy to identify outward and read out in the order from left to right and from bottom to top.
(2) The polarity of the installation element shall not be wrong, and the corresponding sleeve shall be put on before installation.
(3) The installation height should meet the specified requirements, and components of the same specification should be installed at the same height as far as possible.
(4) The general installation sequence is from low to high, from light to heavy, from easy to difficult, and from general components to special components.
(5) The components on the printed board should be distributed as evenly as possible, with the same density and neat and beautiful arrangement. Oblique arrangement, cross arrangement and overlapping arrangement are not allowed.
(6) There should be a reasonable gap of 0.2~0.4mm between the lead diameter of components and the aperture of printed board.
(7) The installation of some special components and MOS integrated circuits should be carried out on the equipotential workbench to avoid electrostatic damage to devices. The heating element should keep a certain distance from the surface of the printed board, and it is not allowed to be installed on the surface. The installation of larger components should be fixed (binding, pasting, bracket fixing, etc.). ).
6. 1.2 assembly method
1. Function method
Functional method is to put a part of electronic products into a complete structural component.
2. Composition method
The component method is to manufacture some parts with uniform external dimensions and installation dimensions, and then the functional integrity of the parts takes a back seat.
3. Functional component method
Functional component method takes into account the characteristics of functional method and component method, and produces structural dimensions and components with functional integrity and standardization.
6. 1.3 connection method
The electrical connection of electronic product assembly mainly adopts printed wire connection, wires, cables and other electrical conductors.
6. 1.4 Wiring and binding
1. wiring
There are four kinds of wires and cables commonly used in electronic products: bare wires, electromagnetic wires, insulated wires and cables and communication cables.
The selection of conductor mainly considers the current flowing through the conductor, which determines the cross-sectional area of conductor core.
Using wires with different colors is convenient to distinguish the nature and function of the circuit and reduce wiring errors.
2. Wiring principle
(1) The circuit distribution parameters should be reduced.
(2) Avoid mutual interference and parasitic coupling.
(3) Try to eliminate the influence of grounding wire.
(4) should meet the requirements of the assembly process.
3. Wiring method
(1) wiring processing.
(2) the sequence of wiring.
6.2 Assembly of Printed Circuit Board
6.2. 1 assembly process
1. Formation of component leads
The basic requirements of lead forming are shown in the following figure. A in the photo? 2mmr？ 2d； H: Figure (a) is 0~2 mm, Figure (b) h? 2mm； C=np(p is the coordinate grid size of printed circuit board and n is a positive integer).
(a) horizontal installation
(a) Horizontal installation (b) Vertical installation
2. Installation method of components
3. Precautions for component installation
(1) After the components are plugged in, the lead shape should be treated by elbow, cutting and molding. , should be processed according to the requirements, and the bending direction of all bent legs should be consistent with the direction of copper foil routing.
(2) When installing the diode, besides paying attention to the polarity, we should also pay attention to the packaging of the shell, especially the glass shell is fragile and the lead is easy to burst when bending; For high current diodes, some lead bodies are used as radiators, so the length of the lead must be determined according to the requirements in the diode specification.
(3) In order to distinguish the electrodes of transistors from the positive and negative electrodes of electrolytic capacitors, colored sleeves are usually added during installation.
(4) High-power triodes are generally not suitable for mounting on printed boards. Due to its high calorific value, printed boards are easily deformed when heated. Assembly process flow
1. Manual control
Components to install? Lead molding? Plug-in Adjust the position? Cut the lead? Fixed position? Welding? test
1. Structure of the whole machine assembly
(1) plug-in structure.
(2) The structural form of the unit box.
(3) Insert box structure.
(4) The structural form of the bottom plate.
(5) the structure of the body.
2. Assembly process requirements of the whole machine structure
(1) structural assembly technology should be relatively independent.
(2) The mechanical structure assembly should have adjustable links to ensure the assembly accuracy.
(3) The connecting structure used in mechanical structure assembly shall ensure convenient installation and reliable connection.
(4) Mechanical structure assembly should be convenient for product adjustment and maintenance.
(5) The fixing and installation of the wiring harness should be beneficial to the organization of production and make the whole machine assembled neatly and beautifully.
(6) Rational use of fasteners.
(7) Measures to improve the impact resistance and vibration resistance of products.
(8) The reliability of line connection shall be guaranteed.
(9) The operating tuning mechanism should be able to work accurately, flexibly and smoothly, and the manual operation feels good.
1. The contents of the whole machine assembly
The assembly of the whole machine includes mechanical and electrical work. Specifically, the content of final assembly includes installing all parts, components and integral parts (such as electromechanical components, printed circuit boards, bases, panels and components installed on them) in different positions according to design requirements, combining them into a whole, and then electrically connecting the parts with wires (wires) to complete a complete function.
2. The basic principle of the whole machine assembly
The goal of the whole machine assembly is to achieve the predetermined technical indicators through reasonable installation technology. The basic principles of installation of the whole machine are: light before heavy, small before big, riveting before assembly, welding before assembly, inside before outside, down before up, flat before high, fragile parts before assembly, and the previous procedure does not affect the installation of the next procedure. The basic requirements for installation are firm and reliable, without damaging components, avoiding damaging the coating of the chassis and components, and without damaging the insulation performance of components. The direction and position of installation parts should be correct.
3. The whole machine assembly process
The technological process of assembling the whole machine is as follows:
Are you ready? Rack? Panel? Component? Exercise? Wired connection? Transmission mechanism? Final assembly inspection? Packaging. Brief introduction of micro-assembly technology
Micro-assembly technology (MPT) is the latest stage in the development of assembly technology. Technically, it still belongs to? Assembly? Category, but it is still far from what we usually call assembly, and the general process mentioned above can not be realized. This technology is developed on the basis of microelectronics and semiconductor technology, especially integrated circuit technology and computer-aided system, and it is the most advanced assembly technology in the contemporary era.
6.4.2 Division of Micro-assembly Technology Level
1. MCM.
2. Silicon wafer assembly (WSI/HWSI).
3. 3D assembly (3D).
Electronic product assembly steps Electronic product assembler mainly refers to clamping, electrical installation and quality inspection after assembly. Production practice has proved that good electrical contact is an important factor to ensure the quality and reliability of electronic products, and the failure of electronic products is closely related to the quality of electrical installation. For example, when welding, there are false welding, virtual welding, wrong welding and missing welding, the wiring will be loose, and the contacts will be short-circuited or open-circuited; If the wiring in high-frequency devices is too long and unreasonable, the high-frequency circuit will be unstable or abnormal. Therefore, in order to make the assembled products reach the expected design purpose, we must pay great attention to the assembly quality, and the production operators must do every production step carefully. Assembly work is a complicated and meticulous work. The assembly principle of electronic products is light before heavy, riveted before assembly, inside before outside, flat before high, and the previous procedure shall not affect the next procedure.
1, technical preparation and production preparation before assembly
(1) technical preparation
Technical preparation mainly refers to reading and understanding the drawings and process documents of products, and being familiar with the design drawings, technical conditions and process requirements of parts and complete machines.
(2) Production preparation
A. prepare tools, fixtures and measuring tools.
B prepare all materials, spare parts and various auxiliary materials according to the schedule in the process documents. 2, the basic requirements of assembly operation
(1) spare parts shall be cleaned and properly kept for future use.
(2) Parts, wires, cables and other processed parts shall meet the assembly requirements. For example, straighten the lead wires of components, bend the feet, etc.
(3) Mechanical assembly such as screw connection and riveting shall be completed with good quality and quantity to prevent loosening.
(4) When welding and installing electrical equipment, the prepared components, leads, etc. shall be welded on the position specified in the installation floor, and then all the redundant sundries and dirt shall be removed and sent to the next working procedure. General technical requirements for assembly process of electronic products
Technical requirements include two aspects: first, mechanical assembly;
The second is electrical installation.
(1) technical requirements for mechanical assembly
A. threaded connection
According to the installation drawings and instructions, select the specified screws and washers and tighten them to the specified positions with appropriate tools.
B. riveting
Rivets are often used to connect some places that need to be connected on the assembly drawing and will not be disassembled again. Before riveting, rivets should be selected according to the requirements of drawings, and riveting should meet the riveting quality standards.
C. Combination and others
For the parts that need to be glued, choose an adhesive that meets the requirements of gluing, and glue the joint according to the requirements of gluing process.
The process of electrical installation requires that electrical installation should ensure reliable electrical performance, beautiful appearance, neatness and good product consistency.
The technical requirements for electrical installation are:
A. Materials, components, spare parts and whole parts used in electrical installation shall have product certificates; Some parts should be sampled according to the sampling regulations and can only be used if they meet the requirements. Otherwise, it shall not be used for installation.
B. When assembling, all components should be in the same direction, neat and beautiful; The marking surface should be outward to facilitate observation and inspection.
C. Before welding, the outgoing wires, core wires and joints of the welded parts shall be fixed by inserting, overlapping or winding respectively according to the requirements of the process documents of the whole machine. For general household appliances, plug-in welding is often used. The lead wires and bare wires of components should not be cut or squeezed.