This professional project for the title of Industrial Engineer, design of a proposal to improve the implementation of the maintenance management plan in the polymer injection molding process based on the philosophy of the Lean Office and RCM methodologies. The application is carried out in a Peruvian plastic injection company where the damaged use of the Maintenance Management plan, the risk due to the low availability of spare parts and personnel, the percentage of raw material reprocessed and the treatment of the Machines were identified Molding The importance of solving this problem is to reduce the low reliability of the equipment, the delay in the delivery of orders and the loss of production. The expected results validated by the simulation of controlled systems that the availability of the personnel had an 83.07% and the unplanned stops of the injection machine were reduced by 30%.