Design And Research Of The Flow Control System Of The Soldering Pen

A new kind of soldering tool that’s name is soldering pen is designed, in view of the facts that solder joints’reliability quality is not enough because the separate of solder and heating source. The control of temperature distribution and liquid solder flow in soldering pen’s melting chamber are two important factors that affect the welding quality of soldering pen. This paper starts from the flow of liquid solder in the melting chamber, discussed the effect of the ratio which from inlet size to feed size on the flow. Through software simulation, analysis size of flow resistance, only in the feed radius and the inlet when the ratio is greater than0.8, less influence reflux effect, conducive to the flow control welding pen, provide theoretical basis for the structure design of the heater. In the temperature control, through the literature and the actual experiment, take PTC thermistor temperature control strategy. Not only can simplify the circuit effectively, achieve high energy utilization rate, but also can very good control of temperature. Using stepper motor control of feeding, the speed control of stepping motor speed from the side to achieve the control flow effect. Using Proteus to simulate the stepper motor feed circuit, and the connecting circuit, through the test, the actual measuring feeding error value is3%and the test value, meet the requirements of control accuracy. For the design of soldering pen flow control system, to control the flow of the experiment, the experimental results show that, the feeding speed size corresponds to the size of the joint, the feed speed is greater, solder volume and quality more. But in the experiment, there are also differences from theory. Reasons for the differences are analyzed, the solder containing flux is the main reason for this phenomenon. The feeding and discharging process of data processing, when the feed velocity is larger, feeding and discharging curve will be more and more close to a slope of1asymptotes, namely the discharging and feeding nearly equal.