In any manufacturing industry, production is the driving force to which most other functions react. The changing business environment in which pharmaceutical manufacturers are acting creates the need for more effective production processes planning and control methods, which are able to deal with uncertainties in internal processes and external deliveries. In this article we have briefly highlighted the challenges and factors affecting Production Planning and Control (PPC) and role of Master Production Schedule (MPS). We will begin this article with the objective of PPC.
The ultimate objective of PPC is to contribute to the profit of organization accomplished by keeping the customers satisfied through the meeting of delivery schedules. The specific objective is to establish routes and schedules for work that will ensure the optimum utilization of materials, workers and machines and to provide the means for ensuring operation of the plant in accordance with these plans.
Challenges in Production Planning and Control
Combining Functions – It is desirable that a minimum changes be made after schedules are established. This objective can be approached if the amount of work scheduled for the factory or department is equal or slightly greater than the production cycle.
Follow-up – When jobs are started and completed on schedule, there should be very little concern about the meeting of commitments. Optimum operation of the plant is attained only if the original plan has been carefully prepared to utilize the manufacturing facilities fully and effectively.
Re-planning – Often required in manufacturing. Changes in market conditions, manufacturing methods, etc. affecting the plant will often indicate that a new manufacturing plan is required.
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Factors Affecting Production Planning and Control
Market Forecast – It will indicate future trends in demand for manufactured products. Work shift policies, plans for an increase or decrease in manufacturing activity are based upon the market forecast and in turn affect the production planning and control.
Sales Order – It is a rewrite of the customer order specifying what has been purchased (product, quantity and authorizing shipment of the goods to the customer). Variation or changes in sales order will drastically affect production planning and control.
Standard Process Sheet – It is prepared by process engineering group or process owner and it is the source of basic data which may include type of machine to be used, time required for processing, etc. For e.g. if any machine is under breakdown, the standard process sheet will be disturbed which in turn affect production planning and control.
Load Charts – These charts are prepared for each workstation or machine in the plant or may be for groups of machines or departments.
Project Planning Method – The product to be produced are manufactured in quantities and their total processing time can be measured. The best known methods are Critical Path Method (CPM) and Program Evaluation and Review Technique (PERT).
Planning is the process of selecting and sequencing activities such that they achieve one or more goals and satisfy a set of domain constraints. Schedules should reflect the temporal relationships between activities and the capacity limitations of a set of shared resources. Master Production Schedule is main driver and information source for further material requirements planning and accompanying calls or supplies and allows making detailed production schedules for production system. The high re-planning frequency in order to overcome the uncertainty induces the system nervousness. The system nervousness can be defined as – State of a system when a minor changes in Master Production Schedule creates significant changes in Materials Requirement Planning (MRP).
The following critical points can be considered in Master Production Schedule:
- Frequent changes in MPS result in due-date changes in open orders, quantity and timing for planned order of end products.
- Mentioned changes are translated into gross requirements changes for products and timing of their delivery.
- Unexpected changes in MPS effect that materials, needed for a particular order may not be available. The availability of materials is often limited due to the fact that suppliers have similar bottlenecks and schedules variations transmitted from sub-tier suppliers.
The following questions can be considered while scheduling MPS:
- How to make initial MPS that is as feasible as possible?
- How to limit the number of re-planning activities?
- How to be reactive to disturbances in materials flow?
- How to provide planners with accurate information about material resources available which often lead to bloated inventory and in accurately promised delivery dates to the customers?
Conclusion
Production planning and control practices will vary widely from plant to plant/organization to organization. Though no production control function can be entirely eliminated, the least control that results in effective operation of the factory is the best control. It must be remembered that production planning and control systems should be tools of management. The objective is not an elaborate and detailed system of controls and records, but rather, the optimum operation of the plant for maximum profits. PPC places an emphasis on the control of work-in-process, the system will be in effect tie together all previous records and forms developed in all planning for the manufacture of the products.
References
- D.R. Towill, “The Seamless Supply chain”, International Journal of Technology Management, Volume 13, 1997.
- G.E. Viera and F. Favetto, “Understanding the complexity of Master Production Scheduling Optimization”, Proceedings of the 18th ICPR, Salerno, Italy, 2005.
- V.D.R. Guide, R. Shiverasta, “A review of techniques for buffering against uncertainty with MRP systems”, Production Planning and Control, Volume 11, 2000.
- V.D.R. Guide, “Scheduling using DBR in a Remanufacturing Environment”, International Journal of Production Research, Volume 34, 1996.
- E. Schragenheim and B. Ronen, “Drum-buffer-rope shop floor control”, Productions and Inventory Management Journal.