PLANNING AND CONTROL OF OPERATIONS
The purpose of production planning and control is to ensure that the operation works effectively and efficiently and obtain products and services as required by the customer. To do this, the operation must have resources: • in the right quantity • at the right time • with the right quality level
VOLUMES AND TIMES
To reconcile volume and time, three different but integrated activities are performed: oload: determines the volume that an operation can handle; sequence: determines the priority of the tasks to be carried out; program: decide start and end times for each task.
LOAD
The load is the amount of work that is assigned to a work center (machine, person, department, etc.)
INFINITE LOAD
FINITE LOAD
Finite loading is an approach that only assigns work to a workplace (person, machine, or groups of people or machines) up to an established limit. This limit is the estimate of the capacity for the work center (according to the times available for loading). No more work is accepted than this capacity
.
Infinite loading is an approach that doesn't limit acceptance of work, but rather tries to handle them.
SEQUENCING
Whether the load is finite or infinite, when work arrives, decisions must be made about the order to do it. This activity is known as sequencing. The priorities given to work in an operation are often a defined set of rules.
PHYSICAL RESTRICTIONS
The physical nature of the materials being processed can determine the priority of the job.
CLIENT PRIORITY
An operation may allow an important or dissatisfied customer or item to be “processed” before others, regardless of the order of arrival. This approach is used in operations whose client base is homogeneous and has many small clients and a few large and important ones.
DELIVERY DATE
Prioritizing by delivery date means that the work sequence is according to the dates, regardless of the size of the work or the importance of the client.
PROGRAMMING
Once the job stream is established, some operations require detailed scheduling with the date and time they should start and end. This is a schedule. Programs are familiar volume and time statements in consumer settings.
PROGRAMMING FORWARD AND BACKWARD
PROGRAMMING FORWARD
Forward scheduling involves starting work as soon as it arrives.
ADVANTAGES OF FORWARD PROGRAMMING
High utilization of labor - workers always start work to be busy. Flexible - the slack in the system allows you to load unexpected work.
PROGRAMMING BACKWARD
Backward programming starts at the last possible moment so it doesn't end late.
ADVANTAGES OF BACKWARD PROGRAMMING
Lower cost of materials - materials are not used until needed, thus delaying adding value until the last minute. Less exposed to risk in case the client makes changes to the program. It tends to focus the operation on the delivery dates to the client.