Optimization for CRAFT TF Coil Turn Insulation Wrapping Machine With Sensor-Based Online Teaching System

China Fusion Engineering Test Reactor (CFETR) is a tokamak under design in China, which is a great important step in the commercial application of fusion energy. Before constructing the CFETR, an R&D project named Comprehensive Research Facility for Fusion Technology (CRAFT) is in progress. An important subproject of the CRAFT is to build a prototype toroidal field (TF) coil for CFETR, and we call it CRAFT TF coil. Similar to the ITER, the CRAFT TF coil is also following the “winding and reaction” manufacturing process, and conductor turn insulation wrapping will be performed after the heat treatment. But the CRAFT TF coil is not a double-pancake design, it is composed of three subwinding packs (WPs), and each sub-WP consists of several multipancakes. Considering this, a new turn insulation automatic wrapping system has been designed and manufactured. Presented in this article are the descriptions of TF coil configuration, turn insulation structure, and design of turn insulation automatic wrapping system. Moreover, mathematical models of the workspace of the wrapping machine, insulation tape tension, and overlap rate are derived, and ways to control the tape tension and overlap rate are elaborated. Turn insulation automatic wrapping trials are also performed to verify the mentioned models and ways. The wrapped insulation tapes have a stable overlap rate and are free from wrinkles. The whole automatic wrapping system has passed the factory acceptance test and is being delivered to the CRAFT TF coil winding workshop.