Research On Pinhole Defect Detection Method Of Latex Products

A series of quality inspections must be performed on condoms before their entering the market.These inspections include the blasting volume and pressure detection,stability and storage period of detection,pinhole defect detection,visible defect detection,and packaging integrity detection.Among these defects,the pinhole defect may result in the failure of contraception and even the spread of sexually transmitted diseases,such as AIDS.Therefore,national standard compulsorily requests that every condom must pass the pinhole defect detection before they can be sold.Thus,improving the detection ability and efficiency is crucial to the condom industry.National standard GB7544-2009 recommends two methods for the test of pinhole defects in condoms:leakage test and wet electrical test.Water leakage test has a good detection ability but poor detection efficiency,so it cannot meet the requirements of large-scale industrial production.Although the detection ability of wet electrical test is a little bit lower than that of water leakage test,wet electrical test has a high detection efficiency and can be automated,thus it is widely used in condom industries.However,after wet electrical testing,condoms must be baking,and baking is a power-consuming process and environment unfriendly.Therefore,condom industries overseas turn to use dry electrical test for pinhole test.In China,the quality of homemade equipment for dry electrical test is too low to meet the industry requirements.In this paper,dry electrical detection method is studied.The conductive brush,instead of conductive rubber strip,is used as electrode.The detection mechanism,voltage boost circuit and test circuit are designed.The effect of the arrangement of bristles on detection ability is studied with the Comsol Multiphysics software.Experiments are performed to compare the detection ability of conductive brush and that of conductive rubber,and to study the effect of test voltage and air humidity on the detection ability.Results show that using conductive brush as electrode can improve the detection ability,and both test voltage and air humidity have a significant effect on detection ability.