Production systems can be classified as Job Shop, Batch, Mass and Continuous Production systems.
Job Shop Production
Job shop production is characterised by manufacturing of one or few quantity of products designed and produced as per the specification of customers within prefixed time and cost. The distinguishing feature of this is low volume and high variety of products. A job shop comprises of general purpose machines arranged into different departments. Each job demands unique technological requirements demands to process on machines in a certain sequence.
The Job-shop production system is followed when there is:
High variety of products and low volume.
Use of general purpose machines and facilities.
Highly skilled operators who can take up each job as a challenge because of uniqueness.
Large inventory of materials, tools, parts.
Detailed planning is essential for sequencing the requirements of each product, capacities for each work centre and order priorities.
Following are the advantages of job shop production:
Because of general purpose machines and facilities, variety of products can be produced.
Operators will become more skilled and competent, as each job gives them learning opportunities.
The full potential of operators can be utilised.
An opportunity exists for creative methods and innovative ideas.
Following are the limitations of job shop production:
Higher cost due to frequent setup changes.
A Higher level of inventory at all levels and hence higher inventory cost.
Production planning is complicated.
Larger space requirements.
According to the American Production and Inventory Control Society (APICS), Batch production is defined “as a form of manufacturing in which the job passes through the functional departments in lots or batches and each lot may have a different routeing.” It is characterised by the manufacture of a limited number of products produced at regular intervals and stocked awaiting sales.
The batch production system is used under the following circumstances:
When there are shorter production runs.
When plant and machinery are flexible.
When plant and machinery set up is used for the production of the item in a batch and change of set up is required for processing the next batch.
When manufacturing lead time and cost are lower as compared to job order production.
Following are the advantages of batch production:
Better utilisation of plant and machinery.
Promotes functional specialisation.
Cost per unit is lower as compared to job order production.
Lower investment in plant and machinery.
Flexibility to accommodate and process number of products.
Job satisfaction exists for operators.
Following are the limitations of batch production:
Material handling is complex because of irregular and longer flows.
Production planning and control are complex.
Work in process inventory is higher compared to continuous production.
Higher set up costs due to frequent changes in set up.