SMT stands for Surface Mount Technology, which is a method of electronic component assembly. It involves mounting components directly onto the surface of a printed circuit board (PCB) rather than inserting them into holes on the board using traditional through-hole technology. SMT technology is characterized by high density, high performance, and high reliability, and it is widely used in various electronic products such as mobile phones, computers, and communication equipment. The main advantages of SMT technology include achieving higher circuit densities, improving production efficiency, reducing PCB size, lowering production costs, and enhancing circuit performance and reliability.
The production process of SMT (Surface Mount Technology) typically includes the following main steps:
1. Component mounting preparation: This step involves preparing SMT equipment and components, including selecting appropriate mounting machines and tools, inspecting the integrity and correctness of the components, and preparing mounting templates.
2. PCB surface treatment: In this step, the surface of the PCB undergoes necessary treatment to ensure that components can be securely attached to the board. Surface treatments may include cleaning, deoxidizing, and applying solder paste.
3. Solder paste printing: Solder paste is applied to the PCB using a printing machine. The position and quantity of solder paste should match the design requirements to ensure the correct mounting of components
4. Component mounting: Components are taken from feeders and accurately mounted onto the solder paste areas of the PCB using a mounting head. Different types of mounting techniques such as pick-and-place machines, wave soldering, or manual placement can be used in this step.
5. Reflow soldering: The PCB is passed through a reflow oven where the solder paste is melted and solidified by controlling the temperature curve, completing the soldering between the components and the PCB. This process securely fixes the components to the PCB and ensures good electrical connections.
6. Inspection and repair: Visual inspection and testing are conducted to ensure that components are correctly mounted and soldered with good quality. If any issues are found, repairs and adjustments need to be made promptly.
7. Cleaning and packaging: The PCB is cleaned to remove solder paste residues and other contaminants, then packaged and labeled for subsequent assembly and use.
These steps constitute the basic process of SMT, but the specific process may vary depending on the type of product, production equipment, and factory workflow.
1. SMT (Surface Mount Technology): An electronic assembly technique that directly solder components onto the surface of a PCB.
2. Placement: The process of precisely positioning components onto the solder pads on the surface of a PCB.
3. Placement Machine: Equipment used for automatically mounting components onto a PCB, typically consisting of nozzles, conveyors, and control systems.
4. Solder Paste: A sticky substance containing metal powder used to coat soldering positions on the PCB surface for component soldering.
5. Solder Paste Printing: The process of applying solder paste onto the PCB surface using a printing machine, usually controlled by a stencil to define the shape and position of the solder paste.
6. Reflow Soldering: Placing the PCB with mounted components into a reflow oven, where heat is applied to melt the solder paste and solder it to the PCB surface and components.
7. Wave Soldering: Passing the PCB through a molten solder wave to solder the pads and components to the PCB.
8. Surface Tension: The surface tension of molten solder, which affects the wetting and spreading of solder paste on the PCB surface.
9. Feeder: Equipment on the placement machine used to supply components and feed them to the placement head.
10. Visual Inspection: Inspection of the assembled PCB's appearance and component placement using a visual system.
11. AOI (Automated Optical Inspection): Automated optical inspection using optical systems and image processing technology to inspect component placement, defects, and solder joint quality during the assembly process.
12. PCBA (Printed Circuit Board Assembly): The process of mounting components onto a PCB and completing soldering.
