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China supplier Topscom,Electronics SMT Pcb assembly Technology manufacturing Summary

Editor:seve wuTime:2018-03-08Views:

 
China supplier Topscom,Electronics SMT Pcb assembly Technology manufacturing Summary and SMT production line equipment Configuration list,
 
How many people who are engaged in PCB or electronic technology know some technical knowledge about SMT, and what is the detailed process?

 
SMD Technology SMT (Surface Mount Technology) is currently the most popular in the electronic assembly industry, the most efficient technology and technology, SMT is surface assembly technology (surfacemounted Technology abbreviation).
SMT is a kind of no pin or short lead surface assembly components (referred to as SMC/SMD, Chinese called chip components)
 
The circuit mounting technology, which is installed on the surface of the printed circuit board (printed CIRCUITBOARD,PCB) or on other substrates, is welded and assembled by means of reflow or dip welding. SMT Features: High density assembly, electronic products, small size, light weight, SMD components of the volume and weight of only the traditional plug-in components of about 1/10, after the general use of SMT, electronic products volume reduction 40%~60%, weight reduction 60%~80%. High reliability and strong anti-seismic ability. Welding point defect rate is low, high frequency characteristic is good. Reduced electromagnetic and RF interference. Easy to automate and improve productivity. Reduce costs up to 30%~50%.
Save material, energy, equipment, manpower, time, etc.
 
SMT composition in general, SMT includes surface mount technology, surface mount equipment, surface mount components, SMT management.
 
Why to use SMT electronic products to pursue miniaturization, the previous use of perforated plug-in components have been unable to shrink. Electronic Product features more complete, the use of integrated circuit (IC) has no piercing elements, especially large-scale, high integration IC, have to use surface patch components. Product batch, production automation, the factory to Low-cost high production, produce quality products to * * customer demand and enhance market competitiveness of electronic components development, integrated circuit (IC) development, semiconductor materials, multiple applications.
Electronic science and technology revolution is imperative, chasing international trend. SMT Basic Process components printing (red glue/solder paste)--> detection (optional AOI automatic or visual inspection)--> mount (the first small device affixed after the big device: high-speed SMD and integrated circuit mounting)--> detection (optional AOI optical/visual inspection)--> welding (using hot air reflow soldering)-- > Detection (can be divided into Aoi optical inspection appearance and functional test testing)--> maintenance (using tools: Welding station and hot air dismantling welding station, etc.)--> plate (manual or slitter machine for cutting plate) process is simplified as: printing-------smd-------welding-------Overhaul (
Test links can be added to control quality in each process Solder paste printing Its role is to paste a 45-degree angle with a scraper to the PCB on the pad, for the components of welding preparation.
The equipment used is a printing press (solder paste printing press), located at the forefront of SMT production line. Part of the installation of the role is the Surface assembly components accurately installed to the fixed position of the PCB. 
Equipment used for Mounter, located in the SMT production line in the back of the printing press, generally for high-speed machines and universal machines in accordance with the needs of the production mix. Reflow soldering its role is to melt the solder paste, so that the surface assembly components and PCB board firmly welded together. 
 
The equipment used for reflow soldering furnace, located in the SMT production line in the back of the Mounter, the temperature requirements are very strict, the need for real-time temperature measurement, the measured temperature in the form of profile. Aoi optical detection of the role of the welding of good PCB board for welding quality inspection. The equipment used is an automatic optical inspection machine (AOI), which can be configured in the appropriate place of the production line according to the need of the inspection.
Some of the reflow soldering, some before reflow. Repair its role is to detect the failure of the PCB board repair. Tools used for soldering iron, repair workstations and so on.
 
Configuration in the Aoi optical inspection after the role of the board to split the PCBA, so that it separate into individual individuals, generally using v-cut and machine cutting mode.
Topscom Technology SMT Technician Introduction of this aspect of the content/smt common knowledge:
 
1. Generally speaking, the SMT shop temperature is 23±7℃. 
 
2. Solder paste printing, the necessary preparation of materials and tools: solder paste, steel plate, scraper, wipe paper, dust-free paper, cleaning agent, mixing knife. 
 
3. The commonly used solder paste composition is sn96.5%/ag3%/cu0.5%. 
 
4. The main ingredient in the paste is divided into two parts: Tin powder and flux. 
 
5. The main role of flux in welding is to remove oxides, damage the surface tension of molten tin, and prevent the oxidation again. 
 
6. The ratio of tin powder to flux (flux) in solder paste is about 1:1, and the weight ratio is about 9:1. 
 
7. The principle of the use of solder paste is FIFO. 
 
8. When used in Kaifeng, solder paste must undergo two important processes to return to temperature and stir. 
 
9. The common production method of steel plate is: etching, laser, electroforming. 
 
The full name of SMT is Surfacemount (or mounting) technology, the Chinese meaning is the surface adhesion (or mount) technology. 
 
The full name of ESD is Electro-staticdischarge, the Chinese meaning is electrostatic discharge. 12. The production of SMT Equipment program, the program includes five of the majority of the five parts of the PCB data; Mark data; Feeder data; Nozzle data; 
 
Part data. 
 
13. Lead-free solder sn/ag/cu 96.5/3.0/0.5 melting point of 217C. 
 
14. The control of the part drying box is relative to the temperature and humidity of 10%. 
 
15. Commonly used passive components (passivedevices) are: resistors, capacitors, inductors (or bipolar), active components (activedevices) are: transistors, IC and so on. 
 
16. Commonly used SMT steel material for stainless steel. 
 
17. The thickness of the commonly used SMT plate is 0.15mm (or 0.12mm). 
 
18. Electrostatic charge produced by the type of friction, separation, induction, electrostatic conduction, etc., electrostatic charge on the electronic industry: ESD failure, electrostatic pollution, electrostatic elimination of the three principles of electrostatic neutralization, grounding, shielding. 
 
19. Inch size length x wide 0603=0.06inch*0.03inch, metric length x Width 3216=3.2mm*1.6mm. 20. Erb-05604-j81 8th Code "4" is expressed as 4 loops with a resistance of 56 ohms. 
 
Capacitance eca-0105y-m31 capacity is c=106pf=1nf=1x10-6f.
 
21.ECN Chinese is called: Engineering change notice; The SWR Chinese are all called: Special Needs work order, must be countersigned by each relevant department, the document Center distributes, side is valid. 
 
5S's specific content for collation, rectification, cleaning, cleaning, literacy. 
 
The purpose of PCB vacuum packaging is dustproof and moisture-proof. 
 
24. Quality Policy: Comprehensive product management, implementation of the system, to provide customer demand for quality, full participation, timely processing, to achieve the goal of 0 shortcomings. 
 
25. Quality Three policy is: do not accept bad products, do not manufacture defective products, do not outflow of defective products. 
 
26.QC Seven means check table, layer method, Plato, causality diagram, scatter map, histogram, control chart. 
 
27. The ingredients of solder paste include: Metal powder, solvent, flux, resistance to vertical flow agent, active agent, according to the weight, metal powder accounted for 85-92%, according to the volume of metal powder accounted for 50%, of which the main components of metal powder is tin and lead, the ratio of 63/37, melting point of 183 ℃. 28. The solder paste must be removed from the refrigerator when the return temperature, the purpose is: to keep the temperature of the solder paste chilled to the normal temperatures, in order to facilitate printing. 
If not back to the reflow in the PCBA after the easy to produce bad for the tin beads.
 
 

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