What is SMT?(九) -- Reflow soldering common knowledge IV
author: Hellen
2022-09-26
87. If the visual inspection section cannot be confirmed, then the BOM, manufacturer's confirmation, and sample board should be followed;
88. If the packing method of parts is 12w8P, the counter Pinth size should be adjusted by 8mm each time;
89. the type of welding machine: hot air type welding furnace, nitrogen welding furnace, laser welding furnace, infrared welding furnace;
90. SMT parts sample trial can use the method: flow line production, hand printing machine mount, hand printing hand mount;
91. commonly used MARK shapes are: round, "ten", square, rhombus, triangle, wanzhi;
92. SMT section due to Reflow Profile improperly set, may cause parts micro crack is preheating area, cooling area;
93. Uneven heating of the two ends of the SMT section is likely to cause: empty welding, offset, tombstone;
94. The Cycle time of high-speed machine and general-purpose machine should be balanced as much as possible;
95. The true meaning of quality is to do it right the first time;
96. SMT machine should first paste small parts, then paste large parts;
97. BIOS is a kind of basic input/output system, the full English is: Base Input/Output System;
98. SMT parts are divided into LEAD and LEADLESS according to the part foot;
99. There are three basic types of common automatic placement machines, successive placement type, continuous placement type and mass transfer type placement machine;
100. SMT process can be produced without LOADER;
101. The SMT process is board feeding system - solder paste printing machine - high speed machine - general purpose machine - large flow soldering - board closing machine;
102. temperature and humidity sensitive parts when opened, humidity card in the circle shows the color blue, the parts can be used;
103. the size of 20mm is not the width of the material belt;
104. short circuit caused by bad printing in the process: a. Insufficient metal content of solder paste, causing collapse b. Excessive tin amount due to excessive hole in the steel plate c. Poor quality of the steel plate, bad under the tin, change the laser cutting template d. Stencil back residual solder paste, reduce the scraper pressure, use the appropriate VACUUM and SOLVENT;
105. General back to the soldering furnace Profile the main purpose of the project in each zone: a. Preheating zone; project purpose: volatilization of flux in the paste. b. Equalization zone; project purpose: flux activation, removal of oxides; evaporation of excess water. c. Soldering zone; project purpose: melting of solder. d. Cooling zone; project purpose: the formation of alloy solder joints, parts feet and pads connected as one;
106. SMT process, the main reasons for the generation of tin beads: PCB PAD design, poor design of steel plate openings, placement depth or placement pressure is too large, Profile curve up slope is too large, paste collapse, paste viscosity is too low.
88. If the packing method of parts is 12w8P, the counter Pinth size should be adjusted by 8mm each time;
89. the type of welding machine: hot air type welding furnace, nitrogen welding furnace, laser welding furnace, infrared welding furnace;
90. SMT parts sample trial can use the method: flow line production, hand printing machine mount, hand printing hand mount;
91. commonly used MARK shapes are: round, "ten", square, rhombus, triangle, wanzhi;
92. SMT section due to Reflow Profile improperly set, may cause parts micro crack is preheating area, cooling area;
93. Uneven heating of the two ends of the SMT section is likely to cause: empty welding, offset, tombstone;
94. The Cycle time of high-speed machine and general-purpose machine should be balanced as much as possible;
95. The true meaning of quality is to do it right the first time;
96. SMT machine should first paste small parts, then paste large parts;
97. BIOS is a kind of basic input/output system, the full English is: Base Input/Output System;
98. SMT parts are divided into LEAD and LEADLESS according to the part foot;
99. There are three basic types of common automatic placement machines, successive placement type, continuous placement type and mass transfer type placement machine;
100. SMT process can be produced without LOADER;
101. The SMT process is board feeding system - solder paste printing machine - high speed machine - general purpose machine - large flow soldering - board closing machine;
102. temperature and humidity sensitive parts when opened, humidity card in the circle shows the color blue, the parts can be used;
103. the size of 20mm is not the width of the material belt;
104. short circuit caused by bad printing in the process: a. Insufficient metal content of solder paste, causing collapse b. Excessive tin amount due to excessive hole in the steel plate c. Poor quality of the steel plate, bad under the tin, change the laser cutting template d. Stencil back residual solder paste, reduce the scraper pressure, use the appropriate VACUUM and SOLVENT;
105. General back to the soldering furnace Profile the main purpose of the project in each zone: a. Preheating zone; project purpose: volatilization of flux in the paste. b. Equalization zone; project purpose: flux activation, removal of oxides; evaporation of excess water. c. Soldering zone; project purpose: melting of solder. d. Cooling zone; project purpose: the formation of alloy solder joints, parts feet and pads connected as one;
106. SMT process, the main reasons for the generation of tin beads: PCB PAD design, poor design of steel plate openings, placement depth or placement pressure is too large, Profile curve up slope is too large, paste collapse, paste viscosity is too low.
What is SMT?(十) -- SMD red glue: Basic knowledge
What is SMT?(八) -- Reflow soldering common knowledge Ⅲ
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