Production planning and control in shop floor
Job production
It involves manufacture of products to meet specific customer requirement of special orders. The quantity involved in usually small. Example of job production are manufacture of large turbo generators, boilers, stream engines, processing equipments, material handling equipments, ship building etc.
Under job production, we may have three types accordingly to the regularity of manufacture namely:
A small no of products produced only once.
A small no of products produced intermittently when, the need arises.
A small no of products produced periodically at known intervals of time.
When the order is to executed only once, there is either scope of improvement of production techniques by introducing intricate method studies, special tools or jigs and fixtures unless the technical requirement justifies it. But if the order is to be repeated, jigs and fixtures, tools as well as specially designed inspection gauges should be carefully considered to reduce the manufacturing cycle time.
Production planning and control function is relatively difficult on job production because of the following reasons:
Every job order is of a different nature and has different sequence of operations. There is no standardized routing for job orders.
Specific job orders are assigned to different work stations as per availability of capacity.
Production schedules drawn depend on the relative priority assigned too various job orders.
Scheduling is dependent on the assessment of production times and estimating is based on judgement.
Planning problem
1. There are varieties of job.
2. Each job has variety of operations to be performed.
3. Process sequences of different jobs are not same.
4. There is no initial machine that only always performs first operation of job. There is no terminal machine that only always performs the last operation of a job.
5. Usually, operations are done with in hours or fractions of hours.
6. Variety of jobs and operations generate multiplicity of semi-finished items waiting further processing.
7. High degree of intermittence needs.
Shop floor control
Shop floor control activities that execute and control shop operations includes loading, sequencing, detailed scheduling, and expediting jobs in production. It coordinates the weekly and daily activities that get job done. Individual jobs are assigned to machines and work centers (loading), the sequence of processing the jobs for priority control is determined, start times and job assignments for each stage of processing are decided (detailed scheduling), and materials and work flows from station to station are monitored and adjusted (expediting).
There are various techniques available for production planning and control in shop floor or job production.
1. Assignment or job loading
In many organizations, there may be more than one facilities available to perform a job. In such cases, it becomes necessary to choose between different alternatives facilities and jobs are allocated to the most time or cost effective facility job combination. Assignment or job loading technique is a quantitative method which optimizes our decision on job scheduling.
2. Job sequencing or prioritization
In all cases of infinite loading, we need to follow sequencing method for optimal loading decision. In some finite loading cases also this technique is used. Priority rules help us to understand which job has to be processed first and in what order other jobs should be processes in a situation where there may be number of jobs and one machine or where there may be ‘n’ jobs and two or three work centers.
3. Johnson’s rule
This sequencing process has been developed by S.M. Johnson and is applied in those cases where a group of jobs are to be processed through more than one work center. It helps to minimize idle time of different work center by prudent job allocation.
4. Gantt or bar charts
Henry Gantt introduced this method in 1917 for use in production planning, scheduling and control. This chart shows the relationship between different activities over a time span. While developing a Gantt chart, time frame, which may be in terms of hours, days, weeks or months, is described in horizontal or ‘X’ axis. Against such time frame, on the vertical or ‘Y’ axis, activities are plotted.
5. Dispatching
Dispatching list is also another widely used technique for job sequencing. Under this method, to start with, jobs are ranked and a relative priority is given may be either based on (a) Due date (b) Critical ratio.
Job production
It involves manufacture of products to meet specific customer requirement of special orders. The quantity involved in usually small. Example of job production are manufacture of large turbo generators, boilers, stream engines, processing equipments, material handling equipments, ship building etc.
Under job production, we may have three types accordingly to the regularity of manufacture namely:
A small no of products produced only once.
A small no of products produced intermittently when, the need arises.
A small no of products produced periodically at known intervals of time.
When the order is to executed only once, there is either scope of improvement of production techniques by introducing intricate method studies, special tools or jigs and fixtures unless the technical requirement justifies it. But if the order is to be repeated, jigs and fixtures, tools as well as specially designed inspection gauges should be carefully considered to reduce the manufacturing cycle time.
Production planning and control function is relatively difficult on job production because of the following reasons:
Every job order is of a different nature and has different sequence of operations. There is no standardized routing for job orders.
Specific job orders are assigned to different work stations as per availability of capacity.
Production schedules drawn depend on the relative priority assigned too various job orders.
Scheduling is dependent on the assessment of production times and estimating is based on judgement.
Planning problem
1. There are varieties of job.
2. Each job has variety of operations to be performed.
3. Process sequences of different jobs are not same.
4. There is no initial machine that only always performs first operation of job. There is no terminal machine that only always performs the last operation of a job.
5. Usually, operations are done with in hours or fractions of hours.
6. Variety of jobs and operations generate multiplicity of semi-finished items waiting further processing.
7. High degree of intermittence needs.
Shop floor control
Shop floor control activities that execute and control shop operations includes loading, sequencing, detailed scheduling, and expediting jobs in production. It coordinates the weekly and daily activities that get job done. Individual jobs are assigned to machines and work centers (loading), the sequence of processing the jobs for priority control is determined, start times and job assignments for each stage of processing are decided (detailed scheduling), and materials and work flows from station to station are monitored and adjusted (expediting).
There are various techniques available for production planning and control in shop floor or job production.
1. Assignment or job loading
In many organizations, there may be more than one facilities available to perform a job. In such cases, it becomes necessary to choose between different alternatives facilities and jobs are allocated to the most time or cost effective facility job combination. Assignment or job loading technique is a quantitative method which optimizes our decision on job scheduling.
2. Job sequencing or prioritization
In all cases of infinite loading, we need to follow sequencing method for optimal loading decision. In some finite loading cases also this technique is used. Priority rules help us to understand which job has to be processed first and in what order other jobs should be processes in a situation where there may be number of jobs and one machine or where there may be ‘n’ jobs and two or three work centers.
3. Johnson’s rule
This sequencing process has been developed by S.M. Johnson and is applied in those cases where a group of jobs are to be processed through more than one work center. It helps to minimize idle time of different work center by prudent job allocation.
4. Gantt or bar charts
Henry Gantt introduced this method in 1917 for use in production planning, scheduling and control. This chart shows the relationship between different activities over a time span. While developing a Gantt chart, time frame, which may be in terms of hours, days, weeks or months, is described in horizontal or ‘X’ axis. Against such time frame, on the vertical or ‘Y’ axis, activities are plotted.
5. Dispatching
Dispatching list is also another widely used technique for job sequencing. Under this method, to start with, jobs are ranked and a relative priority is given may be either based on (a) Due date (b) Critical ratio.
Nice Post.
ReplyDeleteI like the way you written the post.
Post is very Informative and easy to understand.
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