Mumbai University > Mechanical Engineering > Sem 7 > Production planning and control

Marks: 5M

Year: May 2016

Dispatching is ‘release of orders and instructions for starting of the production for an item in accordance with the ‘route sheet’ and schedule charts’.

Dispatching is defined as setting production activities in motion through the release of orders (work order, shop order) and instructions in accordance with the previously planned time schedules and routings. Dispatching also provides a means for comparing actual progress with planned production progress.

Principles of Dispatching

1. Checking the availability of material and then taking appropriate action to have it transferred from the main stores to the point at which it is needed.
2. Ensuring that all production aid is ready when needed and then having them issued to manufacturing departments.
3. Obtaining specific drawings from the drawing office.
4. Informing the process section that production is commencing.
5. At the conclusion of the manufacturing, ensure that all the drawings, layout and tools are withdrawn and returned to their correct location.
6. Dispatching is an important step as it translates production plans into actual production.

Commonly Used Priority Rules

First come, first served (FCFS): Jobs are processed in the order in which they arrive at a machine or work center.

Last come, first served (LCFS): The last job into the work center or at the top of the stack is processed first.

Earliest due date (EDD): The job due the earliest has the highest priority.

Shortest processing time (SPT): The job that requires the least processing time has the highest priority.

Longest processing time (LPT): The job that requires the longest processing time has the highest priority.

Critical Ratio (CR): The job with the smallest ratio of time remaining until due to its processing time remaining has the highest priority.

Stack per remaining operations (S/R0): The job with the least stack per remaining operations is given the highest priority. Calculate by dividing stack by remaining operations.

Dispatching functions include;

1. Providing for movement of raw materials from stores to the first operation and from one operation to the next operation till all the operations are carried out.
2. Collecting tools, jigs and fixtures from tool stores and issuing them to the user department or worker.
3. Issuing job orders authorizing operations in accordance with dates and times as indicated in schedules or machine loading charts.
4. Issue of drawings, specifications, route cards, material requisitions and tool requisitions to the user department.
5. Obtaining inspection schedules and issuing them to the inspection section.
6. Internal materials handling and movement of materials to the inspection area after completing the operation, moving the materials to the next operation center after inspection, and movement of completed parts to holding stores.
7. Returning jigs and fixtures and tools to stores after use.

Expediting/follow-up /Progressing

• Expediting or progressing ensures that, the work is carried out as per the plan and delivery schedules are met.
• Progressing includes activities such as status reporting, attending to bottlenecks or holdups in production and removing the same
• controlling variations or deviations from planned performance levels following up and monitoring progress of work in all stages of production,
• co-ordinating with purchase, stores, tool room and maintenance departments and modifying the production plans and re plan if necessary.

Need for expediting may arise due to the following reasons

1. Delay in supply of materials.
2. Excessive absenteeism.
3. Changes in design specifications.
4. Changes in delivery schedules initiated by customers.
5. Break down of machines or tools, jigs and fixtures.Errors in design drawings and process plans