Maintenance machine cnc milling lunan xhs7145 mohd fadhil nim : 1604002010013 jurusan teknik mesin, program diploma iii fakultas teknik universitas syiah kuala email: mohdfadhilyz@gmail.com abstract the production process can run effectively and efficiently when the machines used in the production process are in good condition and normal. although the treatment system is done by the company during this time using the system preventive and corrective maintenance, but in the implementation there are still problems. the problem is due to unplanned and the absence of standard operation procedure (sop) in the maintenance section to overcome the damage of cnc milling machine. companies that do production activities without regard to maintenance activities, then the company is at risk of sacrificing the machine and the future of the company, because in the long term the company will have difficulties in the production process. the purpose of maintenance in computer numerical