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Production Planning and Control Unit II
Production Production is a process whereby raw material is converted into semi finished products and thereby adds to the value of utility of products, which can be measured as the difference between the value of inputs and value of outputs.
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A Vasudeva Reddy, Asst. Prof. KLUBS
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Production function Production function encompasses the activities of procurement, allocation and utilization of resources. The main objective of production function is to
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produce the goods and services demanded by the customers in the most efficient and economical way.
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PRODUCT DESIGN Product design consists of form and function:
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form designing includes decisions regarding its shape, size, color and appearance of the product, functional design involves the working conditions of the product Factors 1. Standardization 7. Product simplification 2. Reliability 8. Quality Commensuration with 3. Maintainability cost 4. Servicing 9. Product value 5. Reproducibility 10. Consumer quality 6. Sustainability 11. Needs and tastes of consumers. A Vasudeva Reddy, Asst. Prof. KLUBS
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DESIGN OF PRODUCTION SYSTEM
Production system is the framework within which the production activities of an enterprise take place. An appropriate designing of production system ensures the coordination of various production operations
Types of Production System:
Continuous production Job or unit production Intermittent production
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Types of Production System Continuous Production: It refers to the production of standardized products with a standard set of process and operation sequence in anticipation of demand.
Also known as mass flow production or assembly line production Ensures less work in process inventory, high product quality and Involves large investment in machinery and equipment.
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oil refineries and cement manufacturing
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Types of Production System Job or Unit production: It involves production as per customer's specification each batch or order consists of a small lot of identical products and is different from other batches.
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Smaller investment in machines and equipment Easily adapted to changes in product design and order size heterogeneous products
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Types of Production System Intermittent Production: Under this system the goods are produced partly for inventory and partly for customer's orders.
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Automobile plants, printing presses, electrical goods.
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TYPES OF MANUFACTURING PROCESS Job production Batch production Mass or flow production Process Production
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Job Production
Job Production: one or few units of the products are produced as per the requirement and specification of the customer. Production is to meet the delivery schedule and costs are fixed prior to the contract
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can provide parts or services for machinery or systems that are otherwise not available, work is generally of a high quality higher cost of production slow compared to other methods
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Batch Production
Batch production: Limited quantities of each of the different types of products are manufactured on same set of machines. Different products are produced separately one after the other
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seasonal items, products bakeries and in the manufacture of sports shoes, pharmaceutical ingredients,
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Mass or Flow Production
Mass or Flow Production: Under this, the production run is conducted on a set of machines arranged according to the sequence of operations. A huge quantity of same product is manufactured at a time and is stocked for sale.
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discrete solid parts (such as fasteners) assemblies of parts (such as household appliances and automobiles).
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Process Production
Process Production: the production run is conducted for an indefinite period. Industrial processes are procedures involving chemical or mechanical steps
Electrolysis Physical processes (cutting, folding, & polishing) Moulding
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Degree of Repetitiveness
Degree of Repetitiveness
Quantity 14
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Production Planning in Manufacturing
Production Planning Hierarchy Long-Range Capacity Planning Aggregate Planning Master Production Scheduling Production Planning and Control Systems
Pond Draining Systems Used in all types of production with perfect demand
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Push Systems (MRP) Used in all types of production but more benefits obtained on job shop
Pull Systems (JIT)
Long-Range (Years), Entire Product Lines
Medium-Range (Months), Product Family Short-Range (several weeks to few months), Specific Product Model Resources required to make a specific product model
Focusing on Bottlenecks
Used in all types of Used in all types of production production but most but more benefits obtained on successful applications are job shop repetitive
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Aggregate Planning In this planning, operations managers develop mediumrange plans of how they will produce products for the next several months. Aggregate Planning provides
Fully loaded facilities – reducing production costs Adequate production capacity to meet demand Plan for the orderly and systematic change of production capacity. Getting the best output from the resources available.
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Steps in Aggregate Planning 1. 2.
Begin with a sales forecast for each product and its demand Total all the individual product or service forecasts into one aggregate demand
3.
4. 5.
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Go for homogenous units for production
Transform the aggregate demand for each time period into workers, materials, machines of production capacity to meet the aggregate demand Develop alternative resource schemes for supply. Select the capacity plan from alternatives to meet the objectives of the organization
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Dimensions of Production Capacity Mow much of each production resource is available? How much capacity is provided by each type of resource? At what step in production do we determine capacity? How much does it cost to scale capacities up or down?
1. 2. 3. 4.
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Master Production Scheduling
MPS sets the quantity of each end item to be completed in each week of the short-range planning horizon. It is a plan for future production of end items End items may be shipped to customers or placed in inventory.
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MPS
Objectives:
To schedule end items to be completed promptly and when promised to customers. To avoid overloading or underloading the production facility. To make the best use of material, labor and equipment; To maintain inventory investment at the required levels.
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Time Fences The MPS can be divided into four sections, each section separated by a point in time called as Time Fence.
1-2 weeks
2-4 weeks +/- 5%
+/- 10%
+/- 20%
Change
Change
Change
No Change
Frozen
4-6 weeks
6+ weeks
Firm Full 22
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Open
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Example: Master Production Scheduling Arizona Instruments produces bar code scanners for consumers and other manufacturers on a produce-to-stock basis. The production planner is developing an MPS for scanners for the next 6 weeks. The minimum lot size is 1,500 scanners, and the safety stock level is 400 scanners. There are currently 1,120 scanners in inventory. The estimates of demand for scanners in the next 6 weeks are shown on the next slide.
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Example: Master Production Scheduling
Demand Estimates WEEK
1
2
3
4
5
6
CUSTOMERS
500 1000 500
200
700 1000
BRANCH WAREHOUSES
200
300
400
500
300
200
MARKET RESEARCH
0
50
0
0
10
0
PRODUCTION RESEARCH
10
0
0
0
0
0
5
6
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A Vasudeva Reddy, Asst. Prof. KLUBS
Example: Master Production Scheduling
Computations
WEEK
1
3
4
CUSTOMERS
500 1000 500
200
700 1000
BRANCH WAREHOUSES
200
300
400
500
300
200
MARKET RESEARCH
0
50
0
0
10
0
PRODUCTION RESEARCH
10
0
0
0
0
0
TOTAL DEMAND
710 1350 900
BEGINNING INVENTORY
1120 410
REQUIRED PRODUCTION ENDING INVENTORY 26
2
0 410
700 1010 1200
560 1160 460
1500 1500
0
560 1160 460
950
1500 1500 950 1250
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Example: Master Production Scheduling
MPS for Bar Code Scanners WEEK
1 0
SCANNER PRODUCTION
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2
3
1500 1500
4 0
5
6
1500 1500
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Production Planning and Control Systems
After MPS,
It is required to plan and control the
Purchase of materials, The production of parts and assemblies Other work necessary to produce products
It can be carried out
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Pond-Draining Systems Push Systems Pull Systems Focusing on Bottlenecks A Vasudeva Reddy, Asst. Prof. KLUBS
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Pond-Draining Approach ` Suppliers
Holding reservoirs of materials to support production
Raw Material Inventory Produce Parts, Subassemblies
Work-in-Process Inventory Assemble Finished Products
Finished Goods Inventory 29
Customers
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Push Systems
Use information about customers, suppliers, and production to manage material flows.
Flows of materials are planned and controlled by a series of production schedules that state when batches of each particular item should come out of each stage of production
Can result in great reductions of raw-materials inventories and in greater worker and process utilization than pond-draining systems 30
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Pull System
Raw materials and parts are pulled from the back of the system toward the front where they become finished goods Raw-material and in-process inventories approach zero Successful implementation requires much preparation
Bottleneck Operations
Impede production because they have less capacity than upstream or downstream stages Work arrives faster than it can be completed Binding capacity constraints that control the capacity of the system. 31
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STEPS OF PRODUCTION PLANNING AND CONTROL
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STEPS OF PRODUCTION PLANNING AND CONTROL
Production planning: Technique of foreseeing every step in a long series of separate operations,
each step to be taken at the right time and in the right place and each operation to be performed in maximum efficiency.
Routing: The operations, their path and sequence are established.
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To perform these operations the proper class of machines and personnel required are also worked out.
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STEPS OF PRODUCTION PLANNING AND CONTROL
Scheduling: It means working out of time that should be required to perform each operation and also the time necessary to perform the entire series as routed, making allowances for all factors concerned.
Loading: loading determines who will do the work as routing determines where and scheduling determines when it shall be done.
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STEPS OF PRODUCTION PLANNING AND CONTROL
Dispatching: Dispatching involves issue production orders for starting the operations.
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of
Movement of materials to different workstations. Movement of tools and fixtures necessary for each operation. Beginning of work on each operation. Recording of time and cost involved in each operation. Movement of work from one operation to another in accordance with the route sheet. Inspecting or supervision of work
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STEPS OF PRODUCTION PLANNING AND CONTROL
Follow Up: Every production programme involves determination of the progress of work, removing bottlenecks in the flow of work and ensuring that the productive operations are taking place in accordance with the plans.
Inspection: This is mainly to ensure the quality of goods.
Corrective measures: Corrective action may involve any of those activities of adjusting the route, rescheduling of work changing the workloads, repairs and maintenance of machinery or equipment, control over inventories of the cause of deviation is the poor performance of the employees 36
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Gantt Chart
Gantt Chart
A GANTT chart is a type of bar chart that illustrates a project schedule. After the PERT/CPM analysis is completed, the following phase is to construct the GANTT chart and then to re-allocate resources and re-schedule if necessary. GANTT charts have become a common technique for representing the phases and activities of a project work breakdown structure. It was introduced by Henry Gantt around 1910 – 1915. 38
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Gantt Chart
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Gantt Chart
Characteristics:
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The bar in each row identifies the corresponding task The horizontal position of the bar identifies start and end times of the task Bar length represents the duration of the task Task durations can be compared easily Good for allocating resources and re-scheduling Precedence relationships can be represented using arrows Critical activities are usually highlighted Slack times are represented using bars with doted lines The bar of each activity begins at the activity earliest start time (ES) The bar of each activity ends at the activity latest finish time (LF).
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Gantt Chart
Advantages
Simple Good visual communication to others Task durations can be compared easily Good for scheduling resources
Disadvantages
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Dependencies are more difficult to visualise Minor changes in data can cause major changes in the chart
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