Single machine scheduling is a technique used to determine the best sequence for companies to use when manufacturing a series of products. As a basic example, one could consider the demands of a printing company that operates just a single piece of printing equipment. This company may be contracted to perform dozens or even hundreds of jobs over a specified time period. Single machine scheduling helps the business decide on the best sequence in which to complete each of these printing jobs. This process results in a schedule that helps the business meet its goals in terms of profit and customer retention.
Without an effective scheduling technique, businesses may have trouble keeping track of different projects or product lines. They may suddenly discover that a product is due to the buyer in just a few days, but find that the machine is tied up with other projects. This could lead to late delivery, which results in unhappy customers. Eventually, this may cause customers to seek out alternate suppliers in an effort to secure products in a more timely fashion.
The single machine scheduling process is particularly important for companies that adopt the modern technique of just-in-time, or lean, manufacturing. Lean manufacturing companies maximize profit and efficiency by keeping inventory and stock to a bare minimum. For these companies, completing a product early can be just as detrimental as completing it too late. Earliness not only ties up resources and requires some form of storage space, but also prevents the machine from being used in a more efficient manner.
Scheduling by hand using pen and paper would be much too time consuming and complex for most companies. Instead, businesses rely on special single machine scheduling software programs on a computer to complete this task. The computer uses an algorithm, or formula, to develop the most effective schedule for each particular application.
Once data about the company and its processes has been entered into the computer, the software can produce an effective schedule in seconds. These algorithms are based on factors such as the number of jobs on the books and the length of each individual product run. They may also incorporate due dates, or even lead times required to obtain resources and materials.
For many companies, the goal of single machine scheduling is to create the minimum level of net tardiness. Most realize that they will be late at times, but the goal is to be late as seldom as possible in order to alienate as few customers as possible. Once the schedule is set, the company can also alert customers to products that will be late, which may help the customer plan accordingly and ultimately aid in retention.