Exercise 4: Short-Term Scheduling

Abstract

Scheduling involves the timing and coordination of operations. Two kinds of scheduling commonly used are the backward and forward scheduling. Scheduling allocates plant and machinery resources, plan human resources, plan production processes and purchase materials. It employs Gantt charts, assignment methods, priority rules, critical ratio constraint, Johnson’s rule, the concept of bottlenecks and the theory of constraints. Essentially, these techniques provide reasonable trade-off between what can be attained as well as customer due dates.

Introduction

Scheduling basically deals with the timing of operations. It is contingent on capacity plans, aggregate plans and master schedules. It begins with capacity planning, which involves facility and equipment acquisition. Then in the aggregate planning stage, decisions regarding the allotment of resources such as facilities, inventory, people, and outside contractors are made. The master schedule then breaks down the aggregate plan and develops an overall schedule for outputs. Finally, the capacity decisions, intermediate planning, and master schedules are translated to short-term schedules which deal with job sequences and specific assignments of personnel, materials, and machinery. (1)

Establishing the timing of the use of particular resources is the main concern of scheduling. Most jobs compete simultaneously for the same resources, and to make matters more complicated, these jobs have specific deadlines. Scheduling takes care of satisfying such requirements through (1) forward scheduling and (2) backward scheduling.

Forward scheduling begins as the job requirements are known. (1) The firm takes an order and then schedules each operation that must be completed in forward time. With forward scheduling, the firm can tell the earliest date that an order can be completed. (3) However, a setback of this approach is that is causes builds-up of WIP, and the meeting due dates is not top priority.

On the other hand, backward scheduling makes sure that the order is handed to the customer upon the deadline. It begins with the due date, scheduling the final operation first and the other job steps in reverse order. (1) the backward schedule tells when an order must be started in order to be done by a specific date.

Effective scheduling helps firms meet due dates or customers or downstream operations, minimize the flow time, minimize work-in-process inventory and minimize idle time of machine and workers. In essence, scheduling is the heart of operations management that needs to be closely monitored to address complications such as machine breakdown, absenteeism, quality problems, and shortages and accommodate sudden changes.

Significance to the Industry and to Everyday Life

Scheduling entails the timing