Lead-free reflow, professional reflow plant, reflow soldering, reflow factory, the Friends of automation brand reflow, lead-free reflow soldering machines. Wave soldering and reflow soldering are two of the more common way, here we talk about the difference between wave and reflow. SMD. Surface mount technology, referred to as SMT, as a new generation of electronic assembly technology has penetrated into all fields, SMT product has a compact structure, small size, resistance to vibration, impact, high-frequency characteristics, high production efficiency. SMT circuit board mounted in the linking process has occupied a leading position. Typical surface mount process is divided into three steps: applying solder paste reflow ---- ----- Step mount components: its purpose is to exert the right amount of solder paste is applied evenly PCB's the pads to ensure chip components and PCB corresponding pads during reflow soldering, to achieve a good electrical connection, and have sufficient mechanical strength. Solder paste is a mixture of alloy powder, paste solder paste and some additives from having certain viscosity characteristics and good touch it. At room temperature, because the paste has a certain viscosity, electronic components can be attached to the PCB pads, the tilt angle is not too large, there is no case where the collision force, the general elements are not moved when welding When the paste is heated to a certain temperature, the molten alloy powder in the solder paste reflow, solder wetting fluid end components and PCB solder pad, the pad was cooled welding ends solder components are interconnected together to form electrical and mechanical with solder connection. Solder paste is applied by a special device on the pad, its equipment: automatic presses, semi-automatic presses, manual printing, semi-automatic paste dispenser or the like. The method is applied to the application of the advantages and disadvantages machine printing larger quantities, delivery time is tight, funding enough for mass production, high production efficiency using complex processes, greater investment in small and medium volume printing manually, easy product development operations, the need to manually lower cost manual positioning, can not be mass-produced manual dispensing general board of the development, repair solder pads without the aid of equipment, research and production can only apply to the pad pitch at 0.6mm above elements dispenser Step Two: Mount yuan This step is attached devices installed or manually mount chip components to accurately printed solder paste or adhesive patch PCB surface corresponding position. There are two kinds of mounting method, the contrast is as follows: Advantages Disadvantages application method applicable machine mount larger quantities, with lead times of tight using a complex process suitable for mass production, large investment to manually mount small batch production, product development, easy to operate , low cost production efficiency according to the skill level required to manually mount the main tools: vacuum suction pen, tweezers, IC absorption and release aligner, low magnification stereo microscope or magnifying glass. The third step: reflow soldering reflow ReflowSoldring literal translation in English, is by re-melting previously assigned to the pads on the printed circuit board is mounted paste solder paste to achieve surface mount components and PCB solder side or solder pins Mechanical and electrical connection between the plate soldering. From the SMT temperature characteristic curve (see photo) analysis principles reflow. First of PCB into the preheat zone 140 ℃ ~ 160 ℃ when the solder paste solvent gas evaporated, while the flux in the solder paste wetting pads, welding end components and pins, solder softens, collapse, covering the pad, the pad, component leads and oxygen isolation; and surface-mount components to get fully warm, then enter the weld zone, the temperature 2-3 ℃ per second international standard rapid heating rates increased solder paste reach a molten state, the liquid solder in pads, components and PCB solder side pins wetting, diffusion, overflow and the return generated mixed metal compound on the bonding interface, the formation of solder joints; and finally into the cooling zone make PCB weld solidification.