The invention relates to a method to improve the welding quality of platinum wire and lug, which includes the following steps: Step 1: bend the lug; Step 2: Put platinum wire inside the bending; Step 3: Adjust welding equipment parameters, voltage: low voltage 30V ~ 36V; Step 4: place the graphite electrode head on the wiring piece and the platinum wire to be welded, keep the two in contact, and apply pressure of 4N/cm2 ~ 6N/cm2; Step 5: Connect the welding loop by stepping on the equipment and welding for 2S ~ 3S. Carbon arc spot welding equipment because of low voltage output, high safety for operators; It makes up for the deficiency of traditional soft brazing method, and its connection strength and reliability are greatly improved, which meets the application requirements of platinum resistance sensor.
Platinum resistance sensors account for a large proportion of aerospace industry sensors, because platinum resistance has stable performance, wide temperature range, high strength, and high precision of manufactured products, which are widely used in aviation temperature sensors. Wound platinum resistance is made of platinum wire wound on the skeleton of insulating materials such as mica and ceramics to make a sensitive element, but the resistance value is output through the latch seat, and the platinum wire and the latch seat are converted through a wiring piece. Soft brazing was used to connect platinum wire and wiring piece before, but due to poor fluidity, complementarity and wettable of solder, the welding performance and weld strength deteriorated. Excessive organizational stress in the weld cooling process caused frequent fracture of platinum wire after brazing, and the final reliability of the product could not be guaranteed.
Graphite carbon arc welding method, the principle of two electrodes for work pressure makes the two layers of metal workpiece under the pressure of two electrodes formed certain contact resistance, and the welding current from the electrode through another electrode formed in the two point contact resistance moment of the hot melt, and the welding current moment from another electrode along the two artifacts flow so they form a loop, not hurt the internal structure of the welding workpieces. Welding head made of graphite end in cone, cone head pointed degree depends on the size of the solder joint, the general head of Imm ~ 2 mm in diameter, welding head by hand operation, easy to the strength of the control, the position of the head and the workpiece, on and off by stamped on the device control circuit, the formation of welding current, platinum wire and lug welding cement, this method USES the handheld welding head of operations, High operability, high connection strength between platinum wire and lug after welding.
Advantages/positive effects: Carbon arc spot welding equipment due to the use of low voltage output, high safety for operators; It makes up for the deficiency of traditional soft brazing method, and its connection strength and reliability are greatly improved, which meets the application requirements of platinum resistance sensor.
