Production Planning and Control Systems Optimization
Systems Planning and Control of Production
Definition: Processes enabling resource dedication forecasting for each task, detailing operation times and scheduling.
When designing planning and production control, consider:
- Installed production capacity (machinery)
- Production quantities
- Production timing
- Inventory levels maintained between periods
The goal is to meet demand while minimizing costs and maximizing product quality. One approach is a hierarchical method, dividing production operations into decision stages to simplify complex processes into manageable parts. This involves two levels:
- Higher Level: Corporate decisions at an aggregate level (medium-term).
- Lower Level: Specific needs management closer to production time at a disaggregated level (short-term).
Aggregation levels include:
- Articles
- Models and families
- Product lines
Tasks in System Planning and Production Control
- Plan capacity requirements and availability.
- Ensure materials are received in sufficient quantity and on time.
- Ensure efficient equipment and facility use.
- Schedule production activities.
- Monitor and control materials, personnel, orders, equipment, and resources.
- Communicate with clients and suppliers daily.
- Meet customer needs in a dynamic environment.
- Provide information for timely reactions.
- Report production basis to other business functions.
Symptoms of Poor Production Planning and Control
- Poor customer service
- Excessive inventory or frequent stockouts
- Inappropriate equipment use
- Lack of preventive maintenance leading to breakdowns
- Worker mishandling
- Large part quantities
- Staff dedicated to resolving production issues due to errors or unnecessary stops, affecting product quality.
Manufacturing Planning and Control Systems (MPCS)
The manufacturing cost of products, quality, and manufacturing time are key functions of the manufacturing planning and control system. This is crucial for achieving minimum cost, high quality, and reduced manufacturing time.
MPCS includes:
- Demand management
- Aggregate production planning
- Product structure
- Production planning
- Material Requirements Planning (MRP)
- Inventory management
- Capacity planning
The primary objective of MPCS is to ensure desired output is produced within a specific period, in the correct amount, with established quality parameters, and at minimal cost.
Planning: A visual representation of all tasks on each machine, work phases, production anomalies, progress, delays, and job completion dates, typically displayed for worker access.
Demand management aims to provide the product quantity needed to satisfy customers.
Aggregate Production Planning
This is the medium-term production plan, using estimated sales figures to plan time and resources for producing the right amount of each product.
Key concepts in aggregate production:
Aggregation: Planning at this level considers families of goods and products generated by individual companies.
- The aggregate plan covers a 6-18 month horizon.
Goals of aggregate planning:
- Generate product volumes to meet demand.
- Use available resources effectively.
- Align with the company’s global strategies.
Strategies:
- Product families must consider current available capacity.
- If demand exceeds capacity, find alternative capacity adjustments to minimize issues.
Adjustment policies are called production strategies, which can be pure or mixed.
Pure strategies include:
- Chase strategy: Produce only volumes required by the market.
- Constant production strategy: Maintain a constant daily production rate, independent of demand variations.
Master Production Schedule (MPS)
The MPS aims to implement the aggregate plan by determining the quantities of products to be produced within a given period, considering plant capacity.
MPS Process:
- Disaggregate the aggregate plan into specific items.
- Define a precise short-term timeframe.
- Relate the plan to short-term data revisions, inventory availability, current orders, and other demand sources to propose an initial MPS.
- Convert the proposal into an Approximate Load Plan and check it against available capacity.
- If inconsistencies exist, modify the proposed MPS; otherwise, approve it.
Planning Horizon (PH):
- The MPS planning horizon should be as short as possible, generally not exceeding three months. Commonly, it is two months, divided into weeks. The PH must be at least equal to the supply time.
Capacity Planning
Once the MPS is determined, its feasibility from a capacity perspective must be assessed by comparing required production capacity with available and planned manufacturing capacity.
Techniques for capacity planning:
- Rough-Cut Capacity Planning: Calculates the load imposed by the MPS on different work centers, producing a prospective Capacity Plan. Requires:
- Time for each operation and defect rate.
- Bill of Materials detailing components and quantities.
With this data, the load generated in each work center (CT) to obtain one unit of each finished product is determined. This requires knowing the total charge time of an item in a CT.
Once the total time for each product in each CT is known, multiply these by the figures in the proposed MPS and accumulate by CT and period to get the Average Capacity Plan for each Work Center.
- Resource Profiles: This technique aims to correct timing issues. After calculating order loads, distribute them across periods considering the finished product’s supply time. Resource Profiles require more time to develop and include periodic capacity lists. The process involves establishing charges per unit of final product and components, accumulating these based on supply times.
MRP System Features
- Defines product component needs through logically related procedures, translating MPS needs into component requirements with dates and amounts.
- Focuses on specific products to be generated.
- Is prospective.
- Offsets item needs based on component delivery times.