Operation scheduling with GT and PBC

Abstract

Generations of managers in industry and of academics in universities, have been intrigued by the problem of how to plan, and more recently how to automate the scheduling of the operations needed to make parts, on the machines and other work centres in a factory. Today, with one possible exception (OPT) (Goldratt 1980), we are no nearer a reliable solution than we were 100 years ago. Early attempts at centralized operation scheduling, were based on Gantt charts or planning boards. Later solutions have used the computer. They all face the problems that with traditional forms of organization, there is a very large number of constraints which affect the solution, and that if a machine-breakdown, absent worker, material shortage or other disaster makes it necessary to change the schedule, it is generally impossible to revise it to suit the new situation quickly enough to keep the factory running. The usual solution is: ‘Tell the foreman to do the best he can’. This paper submits that the introduction of group technology (GT), coupled with period batch control (PBC), so simplifies the problem, that with minor analytical assistance the GT group foremen can do their own operation scheduling, more reliably and cheaply than it can be done by the computer.