1. Generally, the temperature specified in the SMT workshop is 25±3℃.

2. During solder paste printing, the materials and tools needed are solder paste, steel plate, squeegee, wiping paper, dust-free paper, cleaning agent, and stirring 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 solder paste are divided into two major parts: tin powder and flux.

5. The main role of flux in welding is to remove oxides, break the surface tension of molten tin, and prevent re-oxidation.

6. The volume ratio of tin powder particles to Flux (flux) in solder paste is about 1:1, and the weight ratio is about 9:1.

7. The principle of taking solder paste is first in, first out.

8. When the solder paste is opened for use, it must go through two important processes: temperature return and stirring.

9. The common manufacturing methods for steel plates are etching, laser, and electroforming.

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

11. The full name of ESD is Electro-static discharge, and the Chinese meaning is electrostatic discharge.

12. When making SMT equipment programs, the program includes five major parts, these five parts 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 controlled relative temperature and humidity of the part drying box is less than ten percent.

15. Common passive devices (Passive Devices) are: resistors, capacitors, point-sensing (or diodes), etc.; Active devices are: transistors, ICs, etc.

16. The commonly used material for SMT steel plates is stainless steel.

17. The commonly used thickness of SMT steel plate is 0.15mm (or 0.12mm).

18. The types of static electricity generation are friction, separation, induction, static conduction, etc.; the impact of static electricity on the electronics industry is: ESD failure, electrostatic pollution; the three principles of electrostatic elimination are static neutralization, grounding, shielding.

19. Imperial size length x width 0603= 0.06inch0.03inch, metric size length x width 3216=3.2mm1.6mm.

20. Resistor ERB-05604-J81 code "4" indicates 4 circuits, resistance is 56 ohms. Capacitor ECA-0105Y-M31 capacity is C=106PF=1NF =1X10-6F.

21. The full Chinese name of ECN is: Engineering Change Notice; The full Chinese name of SWR is: Special Requirement Work Order, which must be signed by all relevant departments.

22. The specific content of 5S is: sorting, tidying, cleaning, cleanliness, and culture.

23. The purpose of vacuum packaging of PCB is to prevent dust and moisture.

24. The quality policy is: quality control, implement the system, provide the quality required by customers; full participation, timely handling, to achieve the goal of zero defects.

25. The three non-policy of quality are: do not accept defective products, do not produce defective products, do not leak defective products.

26. Among the seven methods of QC, the 4M1H in the fishbone cause search refers to (Chinese): people, machines, materials, methods, and environment.

27. The ingredients of solder paste contain: metal powder, solvent, flux, anti-sagging agent, and activator; by weight, the metal powder accounts for between eighty-five and ninety-two percent, and by volume, the metal powder accounts for fifty percent; The main component of the metal powder is tin and lead, with a ratio of 63/37 and a melting point of 183℃.

28. When using solder paste, it needs to be taken out of the refrigerator for temperature return. The purpose is: to restore the temperature of the refrigerated solder paste to room temperature for printing. If it does not return to temperature, it is easy to produce tin beads after PCB A enters Reflow.

29. The file supply modes of the machine are: preparation mode, priority exchange mode, exchange mode, and speed connection mode.

30. The PCB positioning methods of SMT are: vacuum positioning, mechanical hole positioning, double-sided clamping positioning, and board edge positioning.

31. The resistance of a resistor (symbol) of 272 is 2700Ω, and the symbol (silk screen) of a resistor with a resistance of 4.8MΩ is 485.

32. The silk screen on the BGA body includes manufacturer, manufacturer part number, specifications, and Datecode/(Lot No) information.

33. The pitch of a 208pinQFP is 0.5mm.

34. Among the seven methods of QC, the fishbone diagram emphasizes finding cause and effect relationships;

35. CPK refers to: the current actual process capability;

36. The flux begins to volatilize and perform chemical cleaning actions in the constant temperature zone;

37. The ideal cooling zone curve and reflow zone curve are mirror images;

38. The solder paste of Sn62Pb36Ag2 is mainly used for ceramic boards;

39. There are four types of fluxes based on rosin: R, RA, RSA, RMA;

40. The RSS curve is a heating→constant temperature→reflow→cooling curve;

41. The PCB material we currently use is FR-4;

42. The PCB warpage specification does not exceed 0.7% of its diagonal;

43. Laser cutting of STENCIL manufacturing is a reworkable method;

44. The commonly used BGA ball diameter on the current computer motherboard is 0.76mm;

45. The ABS system is an absolute coordinate system;

46. The error of the ceramic chip capacitor ECA-0105Y-K31 is ±ten percent;

47. The material of the PCB currently used by the computer is: fiberglass board;

48. The packaging of SMT parts has a reel diameter of 13 inches and 7 inches;

49. The general SMT stencil hole should be 4um smaller than the PCB PAD to prevent the phenomenon of solder ball defects;

50. According to the "PCBA Inspection Specification", when the two-face angle is >90 degrees, it indicates that the solder paste has no adhesion to the wave solder body;

51. After the IC is unpacked, the humidity display card shows that the humidity is greater than thirty percent, indicating that the IC is damp and hygroscopic;

52. The correct weight ratio and volume ratio of tin powder and flux in the solder paste composition are 90:10, 50:50;

53. The early surface mounting technology originated from the military and aviation electronics fields in the mid-1960s;

54. The commonly used solder paste Sn and Pb contents of SMT are: 63Sn+37Pb;

55. The common feeding interval of the 8mm tape reel is 4mm;

56. In the early 1970s, a new SMD appeared in the industry, the "Sealed Leadless Chip Carrier", often referred to as HCC;

57. The resistance of the component symbolized as 272 should 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℃;

60. The material of electronic components used in large quantities in SMT is ceramic;

61. The suitable temperature of the reflow oven temperature curve is 215℃;

62. During the inspection of the tin furnace, the temperature of the tin furnace is more suitable at 245℃;

63. The opening types of steel plates are square, triangle, circle, star, and Benlei;

64. There is no directionality for SMT segment resistors;

65. The solder paste currently sold on the market actually only has 4 hours of stickiness;

66. The rated air pressure generally used by SMT equipment is 5KG/cm2;

67. The tools for SMT parts repair are: soldering iron, hot air extractor, solder suction gun, tweezers;

68. QC is divided into: IQC, IPQC, .FQC, OQC;

69. High-speed placement machines can mount resistors, capacitors, ICs, and transistors;

70. Features of static electricity: small current, greatly affected by humidity;

71. What kind of welding method is used when the front PTH and the back SMT pass through the tin furnace? Disruptive double-wave welding;

72. Common inspection methods in SMT: visual inspection, X-ray inspection, machine vision inspection

73. The heat transfer method for repairing parts of chromium iron is conduction + convection;

74. The main component of the solder ball of the current BGA material is Sn90 Pb10;

75. Steel plate manufacturing methods laser cutting, electroforming, chemical etching;

76. The temperature of the soldering furnace is measured by: using a thermometer to measure the applicable temperature;

77. The welding condition of the SMT semi-finished product of the reflow furnace at the exit is that the component is fixed on the PCB;

78. The development process of modern quality management is TQC-TQA-TQM;

79. ICT testing is bed of nails testing;

80. The ICT test can test electronic components using static testing;

81. The characteristics of solder are that the melting point is lower than other metals, the physical properties meet the conditions, and the fluidity is better than other metals at low temperatures;

82. When changing the process conditions of the reflow furnace parts, you need to remeasure the curve;

83. Siemens 80F/S is a more electronic control drive;

84. The solder paste thickness meter uses Laser light to measure: solder paste thickness, solder paste thickness, and the width of the solder paste printout;

85. SMT part feeding methods are vibratory feeder, disc feeder, reel feeder;

86. What mechanisms does SMT equipment use: cam mechanism, side rod mechanism, screw mechanism, sliding mechanism;

87. If it cannot be confirmed at the inspection stage, you need to follow which operations BOM, manufacturer confirmation, sample board;

88. If the part packaging method is 12w8P, then the Pinth size of the counter must be adjusted to advance 8mm each time;

89. Types of reflow machines: hot air reflow oven, nitrogen reflow oven, laser reflow oven, infrared reflow oven;

90. Methods that can be used for SMT part sample trial production: streamline production, hand-print machine placement, hand-print hand placement;

91. Common MARK shapes are: circle, "cross" shape, square, diamond, triangle, W shape;

92. In the SMT section, the cause of component micro-cracking due to improper setting of Reflow Profile is the preheating zone and cooling zone;

93. In the SMT section, the two ends of the component are unevenly heated and are prone to: empty welding, offset, tombstone;

94. The Cycle time of high-speed machines and versatile machines should be as balanced as possible;

95. The true meaning of quality is to do well every time;

96. The placement machine should first place small components and then place large components;

97. BIOS is a basic input-output system, the full English is: Base Input/Output System;

98. According to whether SMT components have legs or not, they can be divided into two types: LEAD and LEADLESS;

99. There are three basic types of commonly used automatic placement machines, sequential placement type, continuous placement type, and large transfer type placement machine;

1. SMT process can be produced without LOADER;

2. The SMT process is a board delivery system-solder paste printer-high-speed machine-versatile machine-reflow oven-board collector;

3. When opening humidity-sensitive components, the color displayed in the circle of the humidity card is blue, and the components can be used; 103. The size specification of 20mm is not the width of the tape;

4. The reasons for short circuits caused by poor printing in the process: a. The metal content of the solder paste is not enough, causing collapse; b. The hole of the steel plate is too large, causing too much tin; c. The quality of the steel plate is not good, and the soldering is not good. Change the laser cutting template; d. There is solder paste on the back of the Stencil, reduce the squeegee pressure, use the appropriate VACCUM and SOLVENT

5. The main engineering purposes of each zone of the general reflow oven Profile are: a. Preheating zone; Engineering purpose: The solvent in the solder paste evaporates. b. Equilibrium zone; Engineering purpose: Flux activation, removal of oxides; evaporation of excess water. c. Reflow zone; Engineering purpose: Melting of solder. d. Cooling zone; Engineering purpose: Formation of alloy solder

Connect with us, follow our journey, and stay updated on our latest innovations through our social media channels:

SMT solution provider

We specialize in Auto Insertion machine and SMT equipments, provide spare parts, sub-assembly, retrofit kit, repair kit, upgrading, training, overhaul service. www.smthelp.com http://file.autoinsertion.com/Southern Machinery Product/SMThelp Auto Insertion PCB assembly requirements.pdf http://file.autoinsertion.com/SMT machine 3D Drawing in Html/S3020A Radial Insertion machine inline 20 stations.html http://file.autoinsertion.com/SMT machine 3D Drawing in Html/S7000T Reel tape terminal inserter 2 heads.html http://file.autoinsertion.com/SMT machine 3D Drawing in Html/S3010A Radial Insertion Machine.html http://file.autoinsertion.com/SMT machine 3D Drawing in Html/S4020A Axial +conveyor+S3020A Radial.html http://file.autoinsertion.com/SMT machine 3D Drawing in Html/THT axial radial PCBA.html https://img.3dsmt.com/album/vFY https://img.3dsmt.com/album/CGV https://img.3dsmt.com/album/HQ2

https://www.youtube.com/c/Smthelping

Explore Recent

One stop solutions for Smart EMS factory

https://ph.smthelp.com/explore/recent

• [LinkedIn Company Page](https://www.linkedin.com/company/smtmachine)

• [LinkedIn Profile](https://cn.linkedin.com/in/smtsupplier)

• [Twitter](https://twitter.com/smtspecialist)

• [Facebook](https://www.facebook.com/autoinsertion)

• [YouTube Channel](https://www.youtube.com/c/Smthelping)

• Browse our machine catalog at [file.autoinsertion.com](https://file.autoinsertion.com) and find machine photos at [ph.smthelp.com](https://ph.smthelp.com).