Summary of experience with industrial superconducting main magnet production for HERA

For HERA (Hadron Electron Ring Accelerator) a total of 453 superconducting dipoles and 246 superconducting quadrupoles has been built by European industry. During the first stage of the fabrication period several technical improvements turned out to be necessary. All magnets have been carefully checked mechanically, optically, and electrically, and have been cold-tested at DESY. The result of these checks gives a good overview of the fabrication quality and gives hints for possible improvements for future superconducting accelerator magnet fabrication. The reproducibility achieved during mass production is very high. The rejection rate for nonconformity with specification was 7.2% overall