For failure-prone manufacturing systems with deterministic machine up time, the switching curve policy, which has a special property and can be characterized by a single parameter, was shown to be optimal. In previous work, the problem of optimal production rate control was studied under the assumption that backlog is allowed. In this paper, the authors consider manufacturing systems in which backlog is not permitted. The authors show that the switching curve policy is still optimal in this case. They also consider the system model in which one machine has three states : down, idle, and operational. This model can reduce maintenance times of the machine, and then reduce its maintenance costs.