Design drawing and process of SMT processing

design drawing and process of SMT processing
The most important design in PCB processing is PCB drawing design Several problems to be noted in the design of circuit board drawings:
First: Create a package that is not in the package library. Before designing a PCB, if the components in the schematIC cannot find a packaging model in the packaging library, you need to create a new packaging model using the component packaging Model Editor. Ensure that the package model of the components used is located in the package library (can be multiple library files) to ensure smooth PCB design.

Second: Set the design parameters of PCB drawings. Set the number of layers, size, color, etc. of PCB according to the requirements of circuit system design.
3. Load netlist. Load the net list generated by the schematic diagram, and automatically load the component packaging model into the PCB design window.
Fourth: Layout. The combination of automatic layout and manual layout can be used to place the component packaging model in an appropriate position within the PCB planning range, even if the component layout is neat, beautiful, and conducive to wiring.
Fifth: Wiring. Set routing design rules and start automatic routing. If the wiring is not completely successful, it can be adjusted manually.
Sixth: design rule check. Check the design planning of the designed PCB (check whether the components overlap, whether the network is short circuited, etc.). If there are errors, modify them according to the error report.
Seventh: PCB board SIMulation analysis. Simulate and analyze the signal processing of PCB, mainly analyze the influence of layout and wiring on various parameters for improvement and modification.
Eighth: Save the output It can save the designed PCB drawing, print in layers, and output the PCB design folder
Advantages of SMT wafer processing technology
With the continuous progress and development of the electronic industry, SMT surface mounting technology has become increasingly mature, and equipment functions are also constantly improving. SMT processing technology has gradually replaced the traditional ink cartridge technology and become the most popular processing technology in the electronic assembly industry. "SMAller, lighter, denser and better" is the biggest advantage of SMT chip processing technology, and it is also the requirement of high integration and miniaturization of current electronic products.
SMT chip processing technology: first, paint solder paste on the surface of PCB pad, then accurately place the metallized terminal or pin of the component on the solder paste of the pad, then connect the PCB to the component, put it into the reflow furnace, and heat the whole to melt the solder paste. After the solder paste is cooLED and solidified, the mechanical and electrical connection between the components and the printed circuit is realized. As a professional SMT chip processing factory, Lingxinte can provide users with various SMT services such as SMT processing rapid proofing, difficult to process SMT chips, and special SMT chip processing. Let's talk to the scientific and technological personnel of Lingxinte to understand the advantages of SMT chip processing technology:
1. Small size and high assembly density of electronic products
The volume of SMT chip module is only about 1/10 of that of traditional chip module, and the weight is only 10% of that of traditional chip module. In general, the use of Surface Mount Technology can reduce the volume of electronic products by 40% - 60%, the quality by 60% - 80%, and the occupied area and weight by a large margin. The SMT chip processing component grid has developed from 1.27MM to the current 0.63MM grid, and the single grid has reached 0.5MM. Through hole installation technology is adopted for component installation, which can improve the assembly density.
2. High reliability and strong anti vibration capability
SMT chip processing uses highly reliable chip components. The component has small volume, light weight and strong anti vibration ability. Automatic production is adopted, with high installation reliability. Generally, the rate of defective solder joints is less than 10 parts per million. The wave soldering technology of through hole plug-in components is one order of magnitude lower than the traditional wave soldering technology, which can ensure that the solder joint defect rate of electronic products or components is low. At present, nearly 90% of electronic products use SMT technology.
high frequency PCB has good characteristics and reliable performance
Because the chip modules are firmly installed, the devices are usually lead-free or short leads, which reduces the impact of parasitic inductance and capacitance, improves the high-frequency characteristics of the circuit, and reduces electromagnetic and radio frequency interference. The maximum frequency of the circuit designed with SMC and SMD is 3GHz, while the chip module is only 500MHz, which can shorten the transmission delay time. It can be used in circuits with clock frequency higher than 16MHz. If MCM technology is used, the high-end clock frequency of computer workstation can reach 100MHz, and the additional power consumption caused by parasitic reactance can be reduced by 2-3 times.
4. Improve production efficiency and realize automatic production
At present, if the perforated PCB printed board is to be fully automated, the area of the original printed board needs to be expanded by 40% so that the insertion head of the automatic part can be inserted into the component, otherwise, the part will be damaged due to insufficient space The automatic placement machine (SM421/SM411) uses a vacuum nozzle to pick and place the components.  The vacuum nozzle is smaller than the shape of the component, which increases the installation density In fact, small parts and fine pitch QFP devices are pasters that use PCBA to realize automatic production of the whole line