Journal of Data Processing Mohammad Rahimi, El-Ghazali Talbi 8 4 2018 http://www.dline.info/jdp/fulltext/v8n4/jdpv8n4_3.pdf In this work we introduced a bi-objective mathematical model using the GAMS software. Besides we calculate the cost associated with the impact of service level on the optimization. Through this current exercise we introduced a new biobjective mathematical model to determine an optimized maintenance-routing policy, simultaneously. Basically the first objective function minimizes the total costs due to traveling and a delay in start time of a Preventive Maintenance (PM)/ Corrective Maintenance (CM) operation. The next intended function considers the service level which is measured based on waiting times before beginning of the CM operations. In the proposed model, we consider time windows in repairing the machines and skill-based technician assignment in performing PM/CM operations. Thus the new framework is modeled as a mixed-integer linear program and is solved by using the software GAMS.