Summary of common terms and knowledge in SMT chip processing industry

smt A summary of common terms and knowledge in the chip processing industry

SMT The chip processing industry is the upstream industrial chain of all electronic products , There is a circuit board inside the electronic product , The circuit board contains many kinds of electronic components , Electronic components need to pass through SMT And  DIP Assemble to the circuit board . Now, Jiangxi yingteli will introduce to you SMT Summary of common industry knowledge points and terms of patch processing (phase I) .




SMT The diameter of the winding disc of the part package 13 " ,7 " ;
2.  The opening type of steel plate is square ﹑ triangle ﹑ circular , Stars , Benlei shape ;
3.  Rosin based flux can be divided into four types : R﹑RA﹑RSA﹑RMA;
4.  At present, solder paste is on the market , Actually only 4 Hours of viscous time ;
5.SMT Generally, the rated air pressure of the equipment is 5KG/cm2;
6.SMT Common inspection methods :  Visual inspection ﹑X Light inspection ﹑ Machine vision inspection 
7. at present BGA The main components of the material are tin balls Sn90 Pb10;

8. The weight ratio and volume ratio of tin powder to flux in the solder paste are correct 90%:10% ,50%:50%;
9. at present SMT The most commonly used solder paste Sn and Pb The content of each is : 63Sn+37Pb;
10. The common material tray bandwidth is 8mm The feeding distance of the paper tape tray is 4mm;

11.SMT The mounter should first paste small parts , Large parts are pasted on the back ;
12.SMT Parts can be divided into... According to the presence or absence of part feet LEAD And LEADLESS Two kinds of ;
13. SMT There is no in the process LOADER It can also produce ;
14. SMT The common basic process of manufacturing is loading machine - Solder Paste Printer - High speed machine - Universal machine - Reflow soldering - Plate retractor ;
15. When the temperature and humidity sensitive parts are opened , The color displayed in the circle of the humidity card is blue , Parts can only be used ;
16. Temperature curve of reflow furnace the maximum temperature of the curve 215 The degree is the most suitable ;
17. The manufacturing method of steel plate is laser cutting ﹑ Electroforming ﹑ Chemical etching ;
18.ICT The test is a needle bed test ;
19. Types of reflow soldering : Hot air welding furnace ﹑ Nitrogen arc welding furnace ﹑ Vacuum welding furnace ﹑ Infrared welding furnace ;
20.SMT Methods that can be used for part sample test ： Streamline production ﹑ Handprint machine mounting ﹑ Handprint and hand mounting ;

21. frequently-used MARK Shape has ： circular ,“ Ten ” The font ﹑ Square , The diamond , triangle , Swastika ;
22.SMT The reflow soldering curve of segment is improperly set , It is the preheating zone that may cause the parts to crack ﹑ Cooling zone ;
23. SMT Uneven heating at both ends of segment parts is easy to cause ： Air welding ﹑ Deviation ﹑ tombstone ;
24. SMT The maintenance tools are ： Soldering iron ﹑ Hot air extractor ﹑ Tin suction gun , Tweezers ;
25.QC It is divided into ：IQC﹑IPQC﹑.FQC﹑OQC;

26. ICT The test can measure electronic parts by static test ;
    27. The measurement curve shall be re measured for the change of reflow soldering part replacement process conditions ;
    28. The solder paste detector uses light to measure : Solder paste flatness ﹑ Thickness of solder paste ﹑ Width of solder paste printing ;
    29.SMT Part Feida has a vibrating feeder ﹑ Disc feeder ﹑ Coil feeder ;
    30.SMT Mechanism classification of equipment : Cam mechanism ﹑ Side bar mechanism ﹑ Screw mechanism ﹑ Sliding mechanism ;

31. High speed chip mounter can mount resistors ﹑ capacitance ﹑ IC﹑ The transistor ;
32. The production line of high-speed machine and universal machine shall be balanced as far as possible ;
33. SMT Cause of short circuit caused by poor solder paste printing ：
a. Insufficient metal content in solder paste , Cause collapse
b. The opening of steel plate is too large , Cause too much tin
c. Poor quality of steel plate , Poor tin deposition , Change the laser cutting template
d. There is solder paste on the back , Reduce the scraper pressure

34. The main purpose of each zone of general reflow furnace :
    a. Purpose of preheating zone ： The solvent in the solder paste volatilizes .
    b. Purpose of uniform temperature zone ： Flux activation , Remove oxides ; Evaporate excess water .
    c. Purpose of back welding area ： Solder melts .
    d. Purpose of the cooling zone ： Alloy solder joint formation , The part foot is connected with the pad as a whole ;

35. SMT The main reasons for the production of tin beads in ：

PCB Poor board design 、 Poor design of steel plate opening 、 The setting depth or pressure is too large 、 The rising slope of temperature control curve is too large , The solder paste collapsed 、 The solder paste viscosity is too low .

In the follow-up, we will present the relevant contents of the second issue to you .

Jiangxi yingteli is a professional SMT Patch processing 、PCBA Patch processing 、PCBA plate 、OEM OEM materials 、DIP Post welding and testing 、 Procurement of electronic components 、 Integrated manufacturing service provider for assembly and packaging of finished products , Welcome to inquire about chip processing business