Many industrial companies in search of a greater production, themetal-mecanical solutions for their production problems through technical and concepts currently in use. Many inches have been made in that sense, they were unfolded several modem production techniques, within those which is underlined the philosophy Just. In Time. The JIT has as objective to make the finished products m a flow balanced according to the requirements of the market with what is minimal of resources. Several of their concepts are revolucionary as the unitary production batch, the next stocks of zero, in the source and the suppliers introduced in the production. In the work is intended to evaluate the move of a company that operates with the system to adapt it to the philosophy JIT, evaluating quantitatively the impact of the inserted in its productive process. For a win be used the simulation as an efficient analysis tool. With the simulation is possible to evaluate the flow of the parts through the machines, work stations and to analyze conflicting demand of the limited resources, furthermore the simulation pmdts us to experience with the model of a system before implementing to the real world. Presented a field work in a metal company mechanics, where they are applied the referring theoretical concepts to the philosophy JIT and the techniques of modeling and systems simulation. The simulation work end when the analyst has their objective or when have not but possible actions that to move the performance of the system.