Mixed model production is the practice of assembling different and distinct models in a line without changeovers with responding to sudden demand changes for a variety of models. In this paper, we specify sequence of models to minimize the conveyer stoppages. We assume our lines are fixed and we can not change the balance of the lines. When the condition of lines like setup cost, demand of each models change, it is important to specify the sequence for minimizing the conveyer stoppages without balancing the line again, because the main lines are fixed. We consider three objective functions, simultaneously: minimizing the variation in actual and required production capacity of the line, minimizing the objectives which increase the chance of conveyer stoppage including: a) minimizing the total setup time, b) minimizing the total production variation cost, and minimizing the total utility work cost. We use a new fuzzy programming for this problem; it can present us an estimator for nearness of conveyer stoppages. We study about sub lines and conveyer velocity and its affect on stoppages.