With the development of technology and the strong demand from the manufacturers for the industry, small-sized veneer-type placement machines are favored. In the SMT production line, it is placed after the dispenser or solder paste printing machine. The head surface mount component accurately places a device on the PCB pad. It is divided into manual and fully automatic. Now the mainstream is mainly automatic placement machine.
16. The commonly used SMT steel plate is made of stainless steel.
17. The thickness of a commonly used SMT steel plate is 0.15 mm (or 0.12 mm).
18. The types of electrostatic charge are friction, separation, induction, electrostatic conduction, etc. The effects of electrostatic charge on the electronics industry are: ESD failure, electrostatic pollution; the three principles of static elimination are static neutralization, grounding, shielding.
19. Inch size length x width 0603 = 0.06 inch * 0.03 inch, metric size length x width 3216 = 3.2 mm * 1.6 mm.
20. Exclusion ERB-05604-J81 8th code "4" is represented as 4 loops with a resistance of 56 ohms. The capacitance of the capacitor ECA-0105Y-M31 is C=106PF=1NF =1X10-6F.
21. ECN Chinese full name: engineering change notice; SWR Chinese full name: special demand work order, must be signed by all relevant departments.
22. The specific content of 5S is finishing, rectifying, cleaning, cleaning and literacy.
23. The purpose of PCB vacuum packaging is to protect against dust and moisture.
24. The quality policy is: quality control, implementation of the system, quality of customer demand; full participation, timely processing, to achieve zero shortcomings.
25. The policy of quality three is: not accepting defective products, not manufacturing defective products, and not discharging defective products.
26. In the QC seven methods, 4M1H refers to (Chinese): people, machines, materials, methods, and environment.
27. The composition of the solder paste contains: metal powder, solvent, flux, anti-sagging agent, active agent; metal powder accounts for between 85 and 92 percent by weight, and metal powder by volume 50%; the main component of the metal powder is tin and lead, the ratio is 63/37, and the melting point is 183 °C.
28. When using the solder paste, the temperature should be removed from the refrigerator. The purpose is to return the temperature of the refrigerated solder paste to room temperature for printing. If you do not return to temperature, the defect that is easily generated after PCB A enters Reflow is tin beads.
29. The file supply modes of the machine are: preparation mode, priority exchange mode, exchange mode and quick connection mode.
30. SMT PCB positioning methods include: vacuum positioning, mechanical hole positioning, bilateral clamp positioning and edge positioning.