A Comprehensive Design Of SLP5.7 Crown-Spring Electrical Connector And The Properties Research

An electrical connector is the basic component for connecting an electro-circuit with another one,or a transmission element with another element.An electrical connector makes the power current or signal stably and reliably as well as the convenient for the combination and maintenance of each parts.The electrical connector is widely used in the field of electrical,electronics,telecommunication,automotive,heavy equipment,rail mass transit,aerospace,military,and satellite and so on.The electrical connector requests to work stably and reliably in vibration shock,high and low temperature thermal fatigue,high humidity corrosion and other harsh environment,which puts forward higher and higher requirements for its material,design and manufacturing process.In this paper the synthetic investigation was achieved for SLP5.7 crown-spring of Amphenol's production from the spring material selection,production failure analysis,laser welding process optimization to the reliability of SLP5.7 batch production.The achieved conclusions are listed as follows:The crown-spring material for SLP5.7 is fixed with C17200 beryllium bronze alloy.The synthetic properties such as the strength,hardness and thermal conductivity of C17200 alloy can meet the requirements of SLP5.7 after solid solution and aging heat treatment.The failure from laser welding contributes 85.5%of total failure of SLP5.7 crown spring in the production process.The main causes of SLP7.5's failure are non-welding,over-welding and cold-welding.Aiming the problem of non-welding and over-welding caused by the roundness deviation on grid or barrel,a special shaping tool is designed,which successfully reduces the defect rate of missing welding and over welding by 52%.Through the comprehensive optimization of welding energy,welding position and welding speed,it is concluded that when the welding length is greater than 0.1mm and the welding energy is 14J,the welding position is 10.8mm and the welding speed is 35 degrees per second,the welding strength reaches more than 200N,which meets the requirements of crown spring grid and barrel welding,and provides a quality control method for the production of SLP5.7.The validation results of SLP5.7 products for one week showed that the DPPM(Defect Part Per Million,i.e.DPPM)of the products decreased from 3,438 to 216.The temperature rise of the electrical connector can be effectively reduced by using glass fiber reinforced nylon PA66 with high thermal conductivity as the shell material of the crown spring.By increasing the contact area between the pin and the socket with enlarging the diameter and the length of the socket and silver plating on the reed surface of crown spring can effectively reduce the contact resistance and control the temperature rise of the electrical connector from the source.Spraying 6-ring polyphenylene ether grease on the SLP5.7 crown spring can significantly reduce the mating force and make the mating process smoother without obvious influence to the contact resistance.