New Contact Resistance Automotive Testing System

Contact resistance has becoming one of important performance reference in nowadays hardware device.Usually it is contact resistance that to judge all the products performance in reliability analysis.The commonly way to measure contact resistance is the Kelvin Four-terminal sensing to correct thermal electromotive force(EMF)by measurement in two directions.While this method is time consuming,inefficiency,and easily got errors by different operators.The paper here proposes a new signal generator way to detect contact resistance based on the analysis of EMF affection on contact resistance.And also base on the principle of contact resistance,contact area and normal force relationship,design a new clamp gauge which can got stable value of contact resistance.Do the accuracy assessment of auto test system to judge its feasibility and practicability.Design EMF affection test of different standard resistances under different current to analyzing the deviation of data under EMF;get a tendency analysis chart of its affection.The larger specimen would get more radiation so as to get higher EMF affection,while EMF affection is steady in a short period and has no relationship with source current.That is the reason why we choose impulse current to do contact resistance measurement so that it can reduce the requirement of equipment capacity,figure out the low level current poor stability,and speed up test period with accuracy.Analyzing contact resistance variation of round type pogo pin,and get the relationship between contact resistance,contact area and normal force.From the testing data,it points out the round type pogo pin are more reliable and get a displacement of pogo pin to ensure the stable resistance.So in this paper,it designs a new clamp gauge to ensure specimen under reliable contact by measure its displacement.Contact resistance testing parameters depend on input current,voltage and selected channels.In the software part,it designs a user-defined VI to identify the current and voltage according to different demand of current or voltage.And it is can save testing value automatically and showing the outputting data curve to make it easier to find wrong data.In this paper,we choose 10 pieces of Double Data Rate(DDR)to be specimens,three operators test three times randomly.And analysis the auto test system by using Minitab software to assess its repeatability and reproducibility.The test results show that the auto test system could get a steady,reliable and meet testing requirement testing data.