Flashcards
L#7 Production Control
Cards in this deck (26)
- 1Define 'manufacturing operations planning & control' (1)Concerned with managing the day-to-day activities of the organisation to satisfy customer demands (1)
- 2Define 'planning' (2)1. A formalised forecast of events that will happen in the future
2. Changes in production variables such as changes in customer decisions, suppliers not delivering on time, machine breakdowns or other unavailability of resources (e.g. staff illness) can cause things to happen differently to what was planned (2) - 3Define 'control' (2)1. Control is the process of coping with changes in production variables
2. Control allows that objectives of the plan to be met, even when assumptions on which the plan was based are no longer applicable - 4Define the 'P:D ratio' (1)Defined as the ratio of total throughput time (P) to the time it takes for the product or service to be delivered to the customer after the order is placed (D)
- 5Draw a diagram showing how various approaches to meeting customer demand can affect the P.D. ratio (1)See notes (1)
- 6What is the relationship between P.D. ratio and uncertainty and risk in production planning and control (1)The lower the P.D. ratio, the lower the uncertainty and risk in production planning and control (1)
- 7What is 'sequencing'? (1)Sequencing is determining the order and time in which various jobs should be carried out with limited resources (1)
- 8Give 8 methods for sequencing (8)1. Physical constraints
2. Customer priority
3. Due date (DD)
4. Last in first out (LIFO)
5. First in first out (FIFO)
6. Longest operation time (LOT)
7. Shortest operation time (SOT)
8. Algorithms such as 'Johnson's' - 9What are the aim of sequencing methods? (1)Aim to improve performance objectives of dependability, speed and cost (1)
- 10What method is used to develop the timing of individual activities after methods for sequencing? (1)Forward and backward scheduling (1)
- 11Explain forward scheduling and its advantages (2)1. Tasks are completed as early as possible
2. This offers high labour utilisation and flexibilty - 12Explain backwards scheduling and its advantages (2)1. Tasks are completed as late as possible
2. This offers lower material costs and less exposure to risks in case of order changes - 13Give the 2 important goals in sequencing (2)1. Minimising the makespan (the time from the start of the first job to to the finishing of the last job)
2. Minimising the lateness (how far tasks go beyond deadlines, averaged and summed) - 14Do the Steve Smith example in the notesSee notes
- 15When can Johnson's algorithm apply? (1)Applies to sequencing n jobs through two workstations (i.e. determining the order of jobs when there are two serial machines) (1)
- 16Give the 4 step of Johnson's algorithm1. Look for the smallest processing time in the remaining jobs
2. If that time is associated with the first workstation then schedule that job first or as near as first to possible. If that time is associated with the second workstation, sequence that job last or as near to last as possible
3. Delete the scheduled job from the task list
4. If there are any tasks remaining, go to 1. - 17Do the Johnson's algorithm example in the notes (1)See notes
- 18What are production management strategies? How are they categorized (2)1. They are concerned with deciding the manner in which signals are given to a production system for starting and stopping work
2. They are usually divided into push and pull control strategies - 19What are push strategies? Give examples (3)1. Those in which the production signals are generated in a top down manner based on forecast demands
2. The signals are then given to workstations which push processed parts to the subsequent workstations
3. Material requirements planning (MRP), Master production schedule (MPS), Manufacturing resource planning (MRPII) and Enterprise resource planning (ERP) are examples of push strategies - 20Draw a diagram to show a push strategy (1)See notes
- 21Explain what 'Materials Requirements Planning (MRP)' is (3)1. MRP is a push system that utilizes the bill of materials (BOM, the breakdown of individual components that form a product) and a master production schedule (MPS) to make timing and volume calculations to meet forecast demands
2. Using the logic contained within the BOM, the production schedule is 'exploded' to determine the volume and timing of sub assemblies.
3. Based on this information, authorisation signals are transmitted to the production facilities downstream - 22Explain what Manufacturing Resource Planning (MRP II) is (2)1. MRP II is a development of MRP where MRP and the information systems that are related to it are integrated into a single framework.
2. A single database is thus held for systems such as invetory management, capacity management and production planning - 23Explain what Enterprise resource planning is (ERP) (5)1. ERP is the extension of MRPII outside the company
2. It allows the resources within the entire enterprise to be managed within a single framework.
3. In ERP, systems such as human resources, finance, etc. are integrated with production management strategies
4. The most important advantage of ERP is perhaps the fact that an enterprise's ERP can communicate with the ERP in other enterprises throughout the supply chain
5. This introduces unprecedented levels of flexibility in supply chain management - 24Summarize pull strategies and draw a diagram illustrating one (4)1. Pull strategies are those which the production signals are generated downstream at a point of delivery to the customer and are transferred upstream to workstations in the production system
2. Starting with the final workstation, each station pulls the processed parts from the previous station.
3. Just-in-time and lean manufacturing are concepts associated with pull strategies
4. See notes for diagram - 25Describe hybrid production management strategies (4)1. MRP and JIT can coexist and be combined in several ways to form a hybrid system
2. The way in which they should be combined depends on the complexity of the product structures, the complexity of the product routing, the volume-variety characteristics and level of control required
3. In general MRP is better for planning and JIT better for control
4. Various ways that these system can be combined include: using separate systems for different products and using MRP for overall control and JIT for internal control - 26Draw the diagram ralting production control strategies, routing and structure complexity (1)See notes
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- Manufacturing Operations and Technology Flashcards on L#7 Production Control, created by Block on 01/05/2014.
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