SMT patch processing 110 knowledge points

1. In general, the temperature of the SMT processing workshop rules of 25 + / - 3 ℃;

2. For the printing of solder paste, materials and materials, tin paste, steel plate, scraper, wiping paper, clean paper, cleaning powder, mixing and cutting knife;

3. The commonly used alloy component is Sn/Pb alloy, and the alloy share is 63/37.

4. The first ingredient in solder paste is two large tin powder and flux.

5. The primary role of flux in soldering is to remove oxides, damage solder exterior tension and avoid reoxidation.

6. The volume ratio of tin powder in tin paste to Flux (Flux) is approximately 1:1, and the ratio of components is about 9:1.

7. The use principle of solder paste is advanced first.

8. When applying the solder paste in kaifeng, two important processes shall be adopted to return to warm and mixing;

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

10. SMT processing Surface is the full name of the mount (or mounting) technology, the Chinese meaning for appearance adhesive (or SMT) skills;

11. The full name of ESD is electro-static discharge, which means electrostatic discharge in Chinese.

12. When making the SMT device, the program includes five major sections, some of which are PCB data. Mark the data; Feeder data; Nozzle data; Part data.

13. Unleaded solder Sn/Ag/Cu 96.5/3.0/0.5 melting point is 217C;

14. The control relative temperature and humidity of the parts drying box is < 10%;

15. Common forced components (Passive Devices) include: resistance, capacitance, point sense (or diodes); Active Devices include: transistors, IC, etc.

16. The raw materials used for SMT steel are stainless steel.

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

18. There are conflicts, separation, induction and electrostatic conduction of electrostatic charge. The effect of electrostatic charge on the electronic industry is: ESD failure, electrostatic pollution; The three principles of electrostatic elimination are electrostatic neutralization, grounding and shielding.

19. The scale length x width 0603 = 0.06 inch * 0.03 inch, the metric long x width 3216 = 3.2 mm * 1.6mm;

20. The exclusion of erb-05604 - J81 "4" indicates that it is 4 circuits with a resistance of 56 ohms. Capacitance ECA - 0105Y - M31 is equal to C = 106PF = 1NF = 1x106f.

21. ECN Chinese is all called: project change notice; SWR Chinese is full name: special needs work order, it is necessary to be signed by each relevant part, the middle of the document distribution, the party is useful;

22. The specific contents of the 5S are cleaning, cleaning, cleaning and quality.

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

24. The quality policy is: all quality control, follow the guidelines, and supply the quality required by customers; Full participation, timely handling, to achieve zero defect policy;

25. The quality of the three is not: do not accept defective products, do not produce defective products, do not outflow defective products;

26. For the reasons of fish bone inspection in the seven methods of QC, 4M1H refers to (Chinese) : human, machine, material, method and environment;

27. The ingredients of solder paste include: metal powder, dissolved, flux, antidrape and active agent; According to the components, metal powder accounted for 85-92 %, and the metal powder accounted for 50% by volume. In metal powder principal component for tin and lead, share is 63/37, the melting point is 183 ℃;

28. The use of solder paste is necessary to remove the temperature from the refrigerator. The intention is: to restore the temperature of the frozen solder paste to normal temperature and to print it. If it is not returned to temperature, it is easy to happen after the PCBA into Reflow.

29. The form of document supply for the machine is: preparation form, priority exchange form, communication form and speed connection form;

30. The PCB positioning methods of SMT include vacuum positioning, mechanical orifice positioning, positioning of the two sides and positioning of plates;

31. The resistance of the screen printing (symbol) 272, resistance at 2700 Ω, the resistance of the resistance is 4.8 M Ω symbols (screen printing) for 485;

32. The silk screen on the BGA ontology includes information such as manufacturer, manufacturer's material number, standard and Datecode/(Lot No);

33. The pitch of 208pinQFP is 0.5mm;

34. In the seven methods of QC, the fishbone diagram focuses on finding causal links;

37. CPK refers to the process ability of current practice;

38. The flux of the flux at the beginning of the temperature zone will be cleaned by chemical cleaning;

39. Relationship between the aspirational cooling zone curve and reflux region curve;

40. The RSS curve is heating, temperature, reflux, cooling curve;

41. The PCB materials we are using are fr-4;

42. PCB warp standard does not exceed 0.7% of its diagonal line;

43. STENCIL manufacturing laser cutting is a way to be able to rework the industry;

44. The BGA ball diameter of the current computer motherboard is 0.76 mm.

45. ABS system is affirmative coordinates;

46. Ceramic chip capacitance ec-0105y - K31 error is plus or minus 10%;

47. The full-active patch machine of the machine is 3? 200 + 10 vac;

48. SMT parts pack their coil plate with a diameter of 13 inches and 7 inches;

49. SMT usually has a hole that is smaller than the PCB PAD 4um to avoid the appearance of tin ball.

50. According to the PCBA check gauge, the solder paste has no adhesion to the wave soldering body when it is in the > 90 degree Angle of the Angle;

51. After IC disassembly, humidity shows that the humidity in the card is greater than 30%.

52. The weight ratio and volume ratio of tin powder and flux for solder paste is 90% : 10%, 50%, 50%;

53. Early appearance stickability was derived from military and avionics categories in the mid-1960s;

54. The contents of Sn and Pb of the solder paste that are most commonly used in the current SMT are respectively: 63Sn + 37Pb;

55. The usual bandwidth of 8mm is 4mm;

56. In the early 1970s, a new type of SMD was used in the industry, which was "sealed and no foot chip carrier", often in the form of HCC;

57. The resistance value of the component with the symbol 272 should be 2.7 K ohms;

58. The capacity of the 100NF component is the same as 0.10 uf;

59. 63 sn + 37 pb eutectic point is 183 ℃;

60. The largest electronic component of SMT is ceramic;

61. The temperature curve of the soldering furnace is the most suitable for its curve of 215C.

62. When the tin furnace is inspected, 245C is suitable for tin furnace.

63. SMT parts are packed with a coil diameter of 13 inches and 7 inches.

64. Open square, triangular, round, star shaped, and the shape of the steel plate;

65. The current computer edge PCB, its raw material is: fiberglass board;

66. The solder paste of Sn62Pb36Ag2 is first tried on which baseboard ceramic plate;

67. The flux can be divided into four types: R, RA, RSA and RMA.

68. There is no directionality in SMT segment exclusion;

69. The current sales of solder paste is a four-hour sticky moment.

70. The additional pressure of the SMT equipment is 5KG/cm2.

71. Positive PTH not used for the double wave welding of the welding method when the SMT is used in the tin furnace;

72. The common inspection methods of SMT: visual inspection, X-ray examination and machine vision inspection

73. The heat conduction method for the part of chromium iron repair is conduction + convection;

74. The current BGA data on the primary Sn90 Pb10 of tin balls;

The manufacturing method of steel plate, laser cutting, electrocasting and chemical etching;

76. Temperature of the arc welding furnace: the temperature of the temperature measuring device is applied to the temperature;

77. The SMT patch of the arc welding furnace is made of the parts fixed to the PCB when the semi-finished products are exported.

78. Process of modern quality management.

79. The ICT test is a needle bed test;

80. The test of ICT can test electronic parts for static testing;

81. Solder characteristics are better than other metals, such as low melting point, satisfactory welding conditions and low temperature.

82. The change of the process condition of the spare parts of the arc welding furnace should be changed from the beginning to the measurement curve;

Siemens 80F/S is due to more electronic controls.

84. The thickness of solder paste is measured by Laser light: tin paste, tin paste thickness, and the width of solder paste;

85. The SMT parts feeding method has oscillating feeder, disk feeder and coil feeder;

86. Which tissues are used in SMT devices: CAM tissue, side bar organization, screw organization, slide organization;

87. If it cannot be admitted, it is required to comply with the work of BOM, manufacturer's recognition and sample board;

88. If the packing method of the parts is 12w8P, the counter Pinth scale shall be adjusted each time to 8mm;

89. The variety of the welding machine: hot-air arc welding furnace, nitrogen welding furnace, laser arc welding furnace and infrared arc welding furnace;

90. Sample test for SMT parts is optional: streamline production, handprint machine stick, hand and hand printing;

The usual MARK shapes are round, "ten", square, diamond, triangle, and zigzag.

92. The SMT segment is improperly set by Reflow Profile, which can form the preheating zone and cooling zone.

93. The heat and non-uniform components of the parts of SMT parts are easily formed: soldering, deflection and stele;

The things that SMT parts repair are: soldering iron, hot air pick up, siphon gun, tweezers;

95. QC is divided into: IQC, IPQC, FQC, OQC.

96. The high speed patch can be fitted with resistor, capacitor, IC and.

Static characteristics: small current, high humidity;

98. The Cycle time of the high speed machine and the general machine should be as balanced as possible;

99. The true meaning of quality is to do well in the first time.

100. The laminator should first post the small part and then the large parts;

101. BIOS is a basic Input and Output System, and the whole English is: Base Input/Output System;

102. SMT parts are not divided into the LEAD and LEADLESS parts according to the parts' feet;

103. Common active placement machines have three basic types, successive placement, successive placement and many transfer placers;

104. No LOADER in the SMT process can also be produced;

105. SMT process is the delivery board system - tin paste printer - high - speed machine - pan - flow welding - receiving machine;

106. When the temperature and humidity sensitive parts are opened, the color in the humidity card circle is blue and the parts can be used.

107. The scale standard 20mm is not the width of the material belt;

108. Reasons for short circuit in the process of printing:

A. The amount of tin paste can not be formed

B. The open hole of steel plate is too large, which constitutes too much tin

C. steel plates are of low quality, lower tin, and laser slit

D. Stencil with tin paste on the back, reducing the pressure of scraper, choosing proper VACCUM and SOLVENT

109. The first project intention of the Profile areas of the usual resolder furnace:

A. Preheating zone; Project intention: the paste in the tin paste is transpiration.

B. Mean temperature zone; Engineering intention: to activate the flux and remove oxides; Transpiration residual water.

C. backweld area; Engineering intention: solder melt.

D. Cooling zone; Engineering intention: alloy solder joint, part foot and solder joint;

110. In SMT processing process, tin beads of primary reason: poor depict PCB PAD, steel plate hole, employ a depth or stress, rofile curve slope is too large, solder paste, solder paste viscosity is too low collapse.