Abstract: Dyeing is a kind of batch process and it operates in a make-to-order mode. Although an order can be made by a number of batches, in order to guarantee the quality, it requires the same production environment for these batches. Thus, in scheduling a dyeing process, one needs to determine the batches for each order and assign them to appropriate vats to satisfy the due date. In this paper, this problem is formulated as a continuous time mixed integer programming model. To efficiently solve this problem, a new method is presented to estimate the time slots. Based on the time slots obtained, the problem can be solved by using LINGO. In this way, a good solution can be found. The proposed method is computationally efficient and can be used in practice. A simple example is given to show the application of the proposed method.

Key words: production scheduling, batch process industry, textile dyeing process