JOY TECHNOLOGY Analysis of SMT pick and place processing frequently problem summary:

1. Generally speaking, the temperature specified for the SMT shop used by the used YAMAHA placement machine is 25±3°C.
2. When solder paste is printed, the materials and tools to be prepared are solder paste, steel plate, scraper, wiping paper, dust-free paper, cleaning agent and mixing knife.
3. The commonly used solder paste alloy composition is Sn/Pb alloy, and the alloy ratio is 63/37.
4. The main components of the solder paste are divided into two parts: tin powder and flux.
5. The main role of flux in soldering is to remove oxides, destroy the surface tension of molten tin, and prevent reoxidation.
6. The ratio of the volume of tin powder to Flux in the solder paste is about 1:1, and the weight ratio is about 9:1.
7. The principle of access to solder paste is FIFO.
8. When the solder paste is used in opening, it must be warmed and stirred after two important processes.
9. Common manufacturing methods for steel plates are: etching, laser, electroforming.

10. The full name of SMT is Surface mount (or mounting) technology, which means surface adhesion (or placement) technology.

11. The full name of ESD is Electro-static discharge, which means electrostatic discharge.
12. When making an SMT device program, the program includes five parts, which are PCB data. Mark data. Feeder data. Nozzle data. Part data.
13. The melting point of lead-free solder Sn/Ag/Cu 96.5/3.0/0.5 is 217C.
14. The relative humidity of the parts drying oven is < 10%.
15. Commonly used passive components (Passive Devices) are: resistors, capacitors, point sense (or diode), etc.; active components (Active Devices) are: transistors, ICs, etc.
16. The commonly used SMT steel plate is made of stainless steel.
17. The thickness of the commonly used SMT steel plate is 0.15mm (or 0.12mm).
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 = 0.06inch * 0.03inch, metric size length x width 3216 = 3.2mm * 1.6mm.

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, file center distribution, to be effective.
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: comprehensive 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 bad products.
26. In the QC seven methods, 4M1H refers to the cause of fish bones (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 85-92% by weight, and metal powder accounts for 50% by volume; The composition is tin and lead, the ratio is 63/37, and the melting point is 183 °C.
28. When using the solder paste, the temperature must 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 PCBA enters Reflow is tin bead.
29. The file supply mode of the machine includes: 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.

31. The silk screen (symbol) is a resistance of 272, the resistance is 2700Ω, and the sign of the resistance of 4.8MΩ (screen printing) is 485.
32. The silkscreen on the BGA body contains information such as the manufacturer, manufacturer's part number, specifications, and Datecode/(Lot No).
33. The pitch of the 208pinQFP is 0.5mm.
34. In the QC seven methods, the fishbone diagram emphasizes the search for causality.
37. CPK refers to the current process capability under actual conditions.
38. The flux begins to volatilize in the constant temperature zone for chemical cleaning.
39. Ideal cooling zone curve and reflow zone curve mirror relationship.

40. The RSS curve is temperature rise → constant temperature → reflux → cooling curve.

41. The PCB material we are currently using is FR-4.
42. The PCB warpage specification does not exceed 0.7% of its diagonal.
43. STENCIL's laser cutting is a way to rework.
44. The BGA ball diameter that is commonly used on computer motherboards is currently 0.76mm.
45. The ABS system is absolute coordinates.
46. Ceramic chip capacitance ECA-0105Y-K31 error is ±10%.
47. Panasert Panasonic automatic placement machine has a voltage of 3?200±10VAC.
48. SMT parts are packaged with a tape reel having a diameter of 13 inches and 7 inches.
49. SMT general steel plate opening is 4um smaller than PCB PAD to prevent the phenomenon of poor solder balls.

50. According to the "PCBA inspection regulations", when the dihedral angle is >90 degrees, it means that the solder paste has no adhesion to the wave soldering body.

51. After the IC unpacking, the humidity on the humidity display card is greater than 30%, indicating that the IC is damp and moisture.
52. The weight ratio and volume ratio of tin powder to flux in the solder paste composition is 90%: 10%, 50%: 50%.
53. Early surface mount technology originated in the military and avionics fields in the mid-1960s.
54. At present, the content of solder paste Sn and Pb most commonly used in SMT is: 63Sn+37Pb.
55. The common paper tape tray with a bandwidth of 8mm has a feed pitch of 4mm.
56. In the early 1970s, a new type of SMD in the industry was a “sealed footless chip carrier”, often referred to as HCC.
57. The resistance of the component with symbol 272 shall be 2.7K ohms.
58. The capacitance of the 100NF component is the same as 0.10uf.
59. The eutectic point of 63Sn+37Pb is 183 °C.

60. The most used electronic parts for SMT are ceramics.

61. The reflow oven temperature curve has the highest curve temperature of 215C.
62. When the tin furnace is inspected, the temperature of the tin furnace is 245C.
63. SMT parts are packaged with a tape reel diameter of 13 inches, 7 inches.
64. The opening pattern of the steel plate is square, triangular, round, star, and the shape of the cone.
65. Currently used computer edge PCB, the material is: fiberglass board.
66. Sn62Pb36Ag2 solder paste is mainly used for which substrate ceramic plate.
67. The rosin-based flux can be divided into four types: R, RA, RSA, RMA.
68. SMT segment exclusion has no directionality.
69. At present, the solder paste sold on the market actually has only 4 hours of sticky time.

70. SMT equipment generally uses a rated air pressure of 5KG/cm2.

71. Front PTH, which welding method is used to spoil double-wave soldering when the SMT is over the tin furnace.
72. Common test methods for SMT: visual inspection, X-ray inspection, machine vision inspection
73. The heat transfer method of ferrochrome repair parts is conduction + convection.
74. At present, the main ball of BGA material is Sn90 Pb10.
75. Methods of making steel plates, laser cutting, electroforming, chemical etching.
76. The temperature of the brazing furnace is as follows: Use the thermometer to measure the applicable temperature.
77. The welding condition of the SMT semi-finished product of the soldering furnace is that the part is fixed on the PCB.
78. The history of modern quality management development TQC-TQA-TQM.
79. The ICT test is a needle bed test.

80. ICT test can test electronic parts using static test.

81. The soldering characteristics are that the melting point is lower than other metals, the physical properties satisfy the welding conditions, and the fluidity at lower temperatures is better than other metals.
82. The change of process conditions for the replacement of the furnace parts is to re-measure the measurement curve.
83. Siemens 80F / S belongs to the more electronic control transmission.
84. Solder paste thickness gauge is measured by Laser: tin paste, solder paste thickness, width of solder paste printed.
85. SMT parts feeding methods include vibrating feeders, disc feeders, and tape feeders.
86. Which institutions are used in SMT equipment: cam mechanism, side rod mechanism, screw mechanism, sliding mechanism.
87. If the visual inspection section cannot be confirmed, it must be in accordance with the operation BOM, manufacturer confirmation, and sample plate.
88. If the part packaging method is 12w8P, the counter Pinth size must be adjusted to 8mm each time.
89. Types of brazing machines: hot air type brazing furnace, nitrogen brazing furnace, laser brazing furnace, infrared brazing furnace.

90. SMT parts sample test can be used: streamlined production, hand-printed machine placement, hand-printed hand placement.

91. Commonly used MARK shapes are: round, "ten" shape, square, diamond, triangle, 4D.
92. The SMT segment is improperly set by the Reflow Profile, and the pre-heating zone and cooling zone may cause micro-cracking of the parts.
93. The unevenness of heat at both ends of the SMT section is easy to cause: empty welding, offset, tombstone.
94. SMT parts repair tools are: soldering iron, hot air extractor, suction gun, tweezers.
95. QC is divided into: IQC, IPQC, .FQC, OQC.
96. High-speed placement machines can be mounted with resistors, capacitors, ICs, transistors.
97. Characteristics of static electricity: small current, greatly affected by humidity.
98. The Cycle time of high speed and general purpose machines should be as balanced as possible.
99. The true meaning of quality is to do it the first time.

100. The placement machine should first affix small parts and then stick large parts.

101. BIOS is a basic input and output system, the whole English is: Base Input / Output System.
102. SMT parts can be divided into LEAD and LEADLESS according to whether the parts are available or not.
103. There are three basic types of common automatic placement machines, the continuous placement type, the continuous placement type and the mass transfer type placement machine.
104. No LOADER can be produced in the SMT process.
105. SMT process is the board system - solder paste printing machine - high speed machine - general machine - choke welding - closing machine.
106. When the temperature and humidity sensitive parts are unsealed, the color in the humidity card circle is blue, and the parts can be used.
107. Size 20mm is not the width of the strip.
108. Reasons for short circuit caused by poor printing in the process:
a. The solder paste metal content is not enough, causing collapse
b. The steel plate opening is too large, resulting in too much tin
c. The quality of the steel plate is not good, the tin is bad, and the laser cutting template is changed.
d. Solder paste on the back of Stencil to reduce blade pressure, using appropriate VACCUM and SOLVENT
109. The main engineering objectives of each area of the general reflow oven profile:
a. Preheating zone; engineering purpose: volatilization of the solvent in the solder paste.
b. Average temperature zone; engineering purpose: flux activation, removal of oxides; evaporation of excess water.
c. reflow zone; engineering purpose: solder melting.
d. Cooling zone; engineering purpose: the formation of alloy solder joints, the parts of the feet and the pads are integrated.
110. In SMT process, the main reasons for tin bead: poor design of PCB PAD, poor design of steel plate opening, excessive depth of part or part pressure, excessive rising slope of rofile curve, collapse of solder paste, low viscosity of solder paste