Research On Improving The Qualification Rate Of A Quasi-fluid Safety System

The quasi-fluid safety system is also called the quasi-fluid delayed release insurance mechanism,and is widely used in fuze design.It has the characteristics of strong environmental adaptability,reliable operation,high timing accuracy,long delay and low cost,and is a typical delay release insurance timer of fuze.Some quasi-fluid safety systems often have problems with excessive warranty release times during years of production and component acceptance.The consequence is the disassembly,reassembly and re-inspection of the entire batch of components.Not only delay the time limit of product delivery,but also increase labor costs.And seriously affect the quality and reputation of the enterprise.Aiming at the problem that the quasi-fluid safety system has a poor warranty time,the causal analysis method is used to determine the structure and size of the drain hole and the surface friction of the sliding parts.Using ANSYS Fluent to simulate the discharge of micro-diameter glass beads,and using the production and acceptance of multiple batches of products in production as a platform,a large number of experimental studies of “adjusting the size of the drain hole structure to change the release time of the safety system” and “increasing the surface roughness value of the slider to change the release time of the safety system” have been carried out,and the experimental results show that: a)the release time of the quasi-fluid safety system has a linear relationship with the size of the chamfer of the discharge hole.By adding a chamfer structure at the outer edge of the body’s drain hole,the release time of the quasi-fluid safety system can be effectively shortened;b)the release time of the quasi-fluid safety system is positively related to the surface roughness value of the sliding parts.By reducing the surface roughness value of the contact surface of the sliding parts,the release time of the quasi-fluid safety system can be effectively shortened.And this guides the processing and assembly of parts for 20 batches of about 180,000 rounds of products,and submit them smoothly for inspection thereby solving the problems of upper limit and out-of-tolerance of safety system release time in this model fuze’s production practice for many years.