Computer Aided Tolerance Design And Analysis Of Feeder System In ITER

Feeder system mainly to power, cooling, measure and diagnose for the magnetsystems in International Thermonuclear Experimental Reactor. It is mainly composed ofcoil terminal box、In－cryostat Feeder、Cryostat Feedthrough and other components. Onthe basis of coil terminal box testing requirements, tolerance analysis software CETOL6σin CATIA is used to design and analysis accuracy for coil terminal box structure. Andcalculating dimension chain by applying extremum and statistics. Optimizing analysisresults that the positions of tested components in the structure can reach testingrequirements.The paper focus on four parts:The first is building three-dimension solid model of coil terminal box in feeder system.Establishing three-dimension solid model of coil terminal box based on three-dimensionmodeling software and to get preliminary research objects. Completes the assembly andsimplification according to actual assembly, including removes non-analysisdimensions-related components and merges the components having no effects on analysisresults. And then reassemble the simplified model.The second is building tolerance model of coil terminal box. Building the tolerancemodel based on simplified three-dimension solid model. And using features in model todetermine benchmarks of model, design dimensions tolerances、geometric tolerance andother accuracy requirements, finish tolerance analysis for coil terminal box accuracyrequirements.The third is building tolerance model of coil terminal box inner structure. Settingcomponents degree of freedoms in terms of assembly sequence on the basis of determinedbenchmarks in CETOL6σ. Build the assemble tolerance model without over-constraint andunder-constraint, define features of components and dimensions accuracy requirements.With assembly accuracy of panels clamping pipes in analysis results, calculating pipes’positions by extremum that cooling pipes variables in6.5mm and bushers beyond the rangeof2.5mm.The forth is optimizing design the analysis results. On the basis of obtained analysisresults, use the sensitivity and contribution data of composition rings that effect assemblyquality to find out the key dimensions. Ensure these dimensions and tolerancerequirements during manufacturing. Optimizing the accuracy in dimension chains until reasonable on the basis of meeting testing requirements and reducing production cost.