Series production of ITER toroidal field coil double pancakes in Japan

•Series production of double-pancakes (DPs) for TF coil is in process.•Winding of 17 DPs, heat treatment of 16 DPs, fabrication of 15 radial plates (RP), transfer of 11 DPs, cover plate (CP) welding of 9 DPs and DP impregnation of 6 DPs were finished and acceptance tests of 5 DPs were successfully completed before end of September, 2016.•In addition, tight tolerances, such as ±0.01% accuracy in conductor length for winding, 1mm flatness in RP fabrication, about 2.5mm (2.1–2.6mm) flatness after 1.5km CP welding and 2mm flatness of completed DP, could be achieved.•These results justify that series production of TF coil DP in Japan is going well.