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People in the industry know that there should not be any food or drink in the PCBA work area, and smoking is prohibited. Actually, there are a lot of skills for PCBA OEM materials. Let's take a look at it.
PCBA foundry processing skills
1. When the solder paste is used in unpacking, it must go through two important processes to be warmed and mixed;
2. Common manufacturing methods for steel plates are: etching, laser, electroforming;
3. The full name of SMT patch processing is Surfacemounttechnology, which means surface adhesion (or placement) technology in Chinese;
4. The flux mainly based on rosin can be divided into four types: R, RA, RSA, RMA;
5. Whether SMT segment exclusion is directional or not;
6. The solder paste currently on the market only needs 4 hours of sticky time in practice;
7. SMT PCB positioning methods include: vacuum positioning, mechanical hole positioning, two-side clamp positioning and board edge positioning;
8. The silk screen (symbol) is the resistance of 272, the resistance value is 2700Ω, and the symbol (the silk screen) of the resistance is 4, 8MΩ is 485;
9. The silk screen on the BGA body includes information such as manufacturer, manufacturer part number, standard and Datecode/(LotNo);
10. The volume ratio of tin powder particles to Flux (flux) in the solder paste is about 1:1, and the weight ratio is about 9:1;
11. The principle of obtaining solder paste is first in, first out;
12. The quality policy for all staff is: all quality control, follow the guidelines, and supply the quality required by customers; the policy of full participation and timely processing to achieve zero defects;
13. The three-not quality policy is: do not accept defective products, do not manufacture defective products, and do not flow out defective products;
14. Among the seven methods of QC, 4M1H refers to the reasons for fishbone investigation respectively (in Chinese): people, machines, materials, methods, and environment;
15. The pitch of 208pinQFP is 0, 5mm;
16. The correct component and volume ratio of tin powder to flux in the solder paste composition is 90%: 10%, 50%: 50%;
17. Commonly used passive components include: resistors, capacitors, inductors (or diodes), etc.; active components include: transistors, ICs, etc.;
18. The raw material of commonly used SMT steel plate is stainless steel;
19. The full name of ECN in Chinese is: Engineering Change Notice; the full name of SWR in Chinese is: Specially needed work orders, which must be countersigned by the relevant parts and distributed in the middle of the documents for their usefulness;
20. The specific content of 5S is sorting, tidying, cleaning, cleaning, quality;
21. The intention of PCB vacuum packaging is to prevent dust and moisture;
22. The hole pattern of the steel plate is square, triangle, round, star, and bevel shape;
23. The raw material of the computer-side PCB currently in use is: glass fiber board FR4;
24. What kind of substrate ceramic board should Sn62Pb36Ag2 solder paste be used for?
25. The thickness of commonly used SMT steel plates is 0, 15mm;
26. There are conflicts, separation, induction, electrostatic conduction, etc. of the types of electrostatic charges; the impact of electrostatic charges on the electronics industry is: ESD failure, electrostatic pollution; the three principles of electrostatic elimination are electrostatic neutralization, grounding, and shielding.
27. Inch size length x width 0603=0, 06inch*0, 03inch, metric size length x width 3216=3, 2mm*1, 6mm;
28. The 8th code "4" of ERB-05604-J81 indicates that there are 4 loops and the resistance value is 56 ohms. The capacitance of the capacitor ECA-0105Y-M31 is C=106PF=1NF=1X10-6F;
29. Generally speaking, the regular temperature of SMT chip processing workshop is 25±3 degree Celsius;
30. When solder paste printing, the materials and things needed to prepare solder paste, steel plate, scraper, wiping paper, dust-free paper, cleaning agent, mixing knife;
31. The commonly used solder paste alloy composition is Sn/Pb alloy, and the alloy share is 63/37;
32. The full name of ESD is Electro-staTIcdischarge, which means electrostatic discharge in Chinese;
33. When manufacturing SMT equipment program, the program includes five major ones, namely PCBdata; Markdata; Feederdata; Nozzledata; Partdata;
34. The melting point of lead-free solder Sn/Ag/Cu96, 5/3, 0/0, 5 is 217C;
35. The control relative temperature and humidity of the parts drying box is <10%;
36. The components of the solder paste include: metal powder, solvent, flux, anti-sagging agent, and active agent; by weight, metal powder accounts for 85-92%, and metal powder accounts for 50% by volume; among them, metal powder is the most important The ingredients are tin and lead, the share is 63/37, and the melting point is 183°C;
37. When solder paste is used, it is necessary to take it out of the refrigerator to return to the temperature. The intention is to restore the temperature of the refrigerated solder paste to normal temperature to facilitate printing. If it does not return to temperature, the defects that are likely to occur after PCBA enters Reflow are tin beads;
38. The document supply form of the machine includes: preparation form, priority communication form, communication form and quick connection form;
39. The main ingredients in the solder paste are divided into two parts: some tin powder and flux.
40. The primary function of flux in soldering is to remove oxides, damage the surface tension of molten tin, and avoid re-oxidation.
