A: Standardized management stage: formulate product testing documents and conduct quality statistics.

B: Total quality management stage: quality management with the participation of all staff.

C: Establishment and implementation stage of ISO management system: ISO9001:2015, ISO14001:2015

D: IATF16949: Establishment and implementation of quality management system in 2016.

E: SPC management application: use statistical management means to improve the quality management level of enterprises.