Common Knowledge of Pick and Place Machines and SMT Production (5)

91. Commonly used MARK shapes include: circle, "ten" shape, square, rhombus, triangle, and swastika;

92. Due to improper setting of Reflow Profile in the SMT section, the parts may be slightly cracked in the preheating area and cooling area;

93. Uneven heating at both ends of SMT parts can easily cause: empty welding, misalignment, and tombstones;

94. The cycle time of high-speed pick and place machines and general-purpose pick and place machines should be as balanced as possible;

95. The true meaning of quality is to do it right the first time;

96. The pick and place machine should place small parts first and then large parts;

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

98. SMT parts are divided into two types: LEAD and LEADLESS based on whether the parts have legs;

99. There are three basic types of common automatic placement machines, continuous placement type, continuous placement type and mass transfer pick and place machine;

100. It can be produced without LOADER in the SMT process;

101. The SMT process is a board feeding system-solder paste printing machine-high-speed pick and place machine-general-purpose machine-separate flow oven -board collecting machine;

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

103. The dimension specification of 20mm is not the width of the tape;

104. Reasons for short circuits due to poor printing during the manufacturing process: a. Insufficient metal content in the solder paste, causing collapse; b. Too large openings in the steel plate, resulting in too much tin; c. Poor quality of the steel plate and poor tin placement. Replace the laser cutting template. d. If there is solder paste remaining on the back of the Stencil, reduce the pressure on the scraper and use appropriate VACUUM and SOLVENT;

105. The main engineering purposes of each area of the general reflow oven furnace Profile: a. Preheating area; engineering purpose: volatilization of the solder paste neutralizing agent. b. Uniform temperature zone; engineering purpose: flux activation, removal of oxides; evaporation of excess water. c. Reflow area; engineering purpose: solder melting. d. Cooling area; engineering purpose: alloy solder joints are formed, and part feet and pads are integrated;

106. The main causes of solder beads in the SMT process are: poor PCB PAD design, poor steel plate opening design, excessive component placement depth or component placement pressure, excessive rise slope of the Profile curve, solder paste collapse, and solder paste viscosity that is too low .