1. Assignment on
Production & Operations Management
submitted by
Harikrishnan S.
Happy V.S.
Honey V.S.
Job Thomas
Yasser Bukari
Group II
Semester – 4 MBA (PT) 2012
submitted to
Dr. Manoj Edward
SCHOOL OF MANAGEMENT STUDIES
Cochin University of Science and Technology
Cochin, Kerala
PIN 682022

2. May 2012
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3. 01. Explain in detail work / method study
Work Study is the systematic examination of the methods of carrying on activities so as to
improve the effective use of resources and to set up standards of performance for the
activities being carried out.
Method Work Higher
study measurement productivity
Work
study
Method study is the collection of techniques used to examine work - what is done and how it
is done - so that there is systematic analysis of all the elements, factors, resources and
relationships affecting the efficiency and effectiveness of the work being studied.
Human factors influencing work study
Managemen
t
Work study
specialist
Supervisors Workers
Work study and the Management
Importance of management must be established
Gaining the management support
Make the management feel that it is not their fault.
Make the management understand the purpose and techniques of work study.
Work Study and the Supervisor
The importance of the supervisor:
Supervisor is the person mostly affected by work study.
Work study is a personal challenge for supervisor.
Fear of taking away the responsibilities influences the work study.
Work Study and the Worker
Work study improves industrial relations:
Workers feel that the management cares for them.
Workers discover that there are managers who highly understand their job.
The feeling of confidence in workers improves.
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4. Workers are more able to carry out their jobs.
Method study
Select the job to be studied
Record by collecting data or by direct observation
Examine by Challenging purpose, place, sequence, and method of work
Develop new methods drawing on contributions of those concerned
Evaluate results of different alternative solutions
Define new method and present it
Install new method and train persons in applying it
Maintain and establish control procedures
Although this linear representation shows the underlying simplicity of method study, in
practice the process is much more one of iteration around the above steps with each
dominating at a different stage of the investigation.
The process often starts with a quick, rough overview in which preliminary data are collected
and examined, before subsequent passes provide and handle more comprehensive and more
detailed data to obtain and analyze a more complete picture.
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5. 02. Explain in detail time study
Time study is a tested method of work measurement for setting standard time for carrying out
a specified work. The aim of time study is to establish a time for a qualified worker to
perform specified work under stated conditions and at a defined rate of working.
Conditions in time study:
• the practitioner (observer) must be fully qualified to carry out Time Study,
• the person performing the task must be fully trained and experienced in the work,
• the work must be clearly defined and the method of doing the work must be effective
• the working conditions must be clearly defined
Essentials for establishing a basic time for specified work are rating and timing
Timing
The observer records the actual time taken to do the element or operation. This usually is in
centiminutes (0.01 min.) and is recorded, using a stop-watch or computerized study board.
Rating
When someone is doing work his/her way of working will vary throughout the working
period and will be different from others doing the same work. This is due to differing speeds
of movement, effort, dexterity and consistency. Thus, the time taken for one person to do the
work may not be the same as that for others and may or may not be 'reasonable' anyway. The
purpose of rating is to adjust the actual time to a standardized basic time that is appropriate
and at a defined level of performance. Rating is on a scale with 100 as its standard rating.
Basic time
Basic time is the standardised time for carrying out an element of work at standard rating.
Steps in Time study
1. Define and document the standard method.
2. Divide the task into work elements.
3. Time the work elements to obtain the observed time for the task.
4. Evaluate the worker’s pace relative to standard performance (performance rating), to
determine the normal time.
5. Apply an allowance to the normal time to compute the standard time.
Application
Time study is often used when
• there are repetitive work cycles of short to long duration,
• wide variety of dissimilar work is performed, or
• process control elements constitute a part of the cycle.
03. Explain inventory management in independent demand items
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6. Inventory management is the process of efficiently overseeing the constant flow of units into
and out of an existing inventory. This process usually involves controlling the transfer in of
units in order to prevent the inventory from becoming too high, or dwindling to levels that
could put the operation of the company into jeopardy.
Inventory is a stock of materials and products used to facilitate production or to satisfy
customer demand. Types of inventory include:
1. Raw Materials (including component parts)
2. Work-In-Process
3. Maintenance/Repair/Operating Supply (MRO)
4. Finished Goods
Reasons for holding inventories include:
1. To maintain independence of operations by de-coupling successive production processes
(buffer inventory).
2. To cover anticipated changes in demand and supply (anticipation stock, as used, for
example, in aggregate production planning to meet anticipated customer demand).
3. To allow flexibility in production scheduling
4. To protect against uncertainties in supply, demand, and lead time (safety stock) and avoid
shortages (stockouts).
5. To guard against inflation and price increases.
6. To permit operations to continue smoothly.
Independent Demand
An inventory of an item is said to be falling into the category of independent demand is not
used to meet a production schedule.
Examples of independent demand: finished goods; retail and distributor inventories; service
inventories; maintenance, repair, and operating (MRO) inventories. MRO includes fuels,
repair parts, office supplies, cleaning supplies
Independent demands for inventories are based on confirmed Customer orders, forecasts,
estimates and past historical data.
Inventory Management techniques
• Fixed order quantity method
• Fixed order Period system
• ABC analysis
Fixed Order Quantity System -
When the Order Point (OP) is reached, order is placed. Fixed order quantity system is known
as the 2 bin system.
• Economic Order Quantity Model (EOQ)
• EOQ for Production Lots
• EOQ with Quantity Discounts
• Models with uncertain demand during lead time
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7. Fixed Order Period System -
The inventory is ordered at “fixed time intervals.” Order enough materials to bring the
inventory to a predetermined level.
ABC analysis
ABC inventory analysis divides inventory items into 3 categories:
A items usually account for at least 60% of annual usage and should be controlled
most closely
B items require a moderate level of control. A and B items should account for at least
80% of annual usage.
C items require less control than other items. These items are those with the least
usage that were not classified as A and B items
Dependent and Independent Demand:
Types of Inventory
Dependent demand: Independent demand:
used to meet a not used to meet a
production schedule production schedule
in manufacturing
Manufacturer Service Company
Raw materials
Finished goods Retail or
Component parts distributor
MRO
inventories
Work-in-process
Service
(WIP)
inventories
MRO
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8. 04. Explain in inventory management in dependent demand items
If the demand for inventory of an item is dependant upon another item, such demands are
categorized as dependant demand.
Raw materials and component inventories are dependant upon the demand for Finished
Goods and hence can be called as Dependant demand inventories.
Managing Raw Material Inventories is far more complicated than managing Finished Goods
Inventory. This involves analyzing and co-coordinating delivery capacity, lead times and
delivery schedules of all raw material suppliers, coupled with the logistical processes and
transit timelines involved in transportation and warehousing of raw materials before they are
ready to be supplied to the production shop floor. Raw material management also involves
periodic review of the inventory holding, inventory counting and audits, followed by detailed
analysis of the reports leading to financial and management decisions. The questions required
to be answered in inventory management are:
How much quantity of materials should be ordered?
When the order is to be placed?
Finished Independent
product Demand
Component 1 Raw material 1
Dependent
Component 2 Raw material 2 Demand
Raw material 3
Inventory Management techniques
• Master production schedule (MPS)
• Material requirements planning (MRP)
• MRP II
• Just in Time (JIT)
Master production schedule (MPS)
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9. A master production schedule (MPS) is a plan in respect of production, staffing, inventory,
etc. to produce individual commodities in each time period. Time-phased plan specifying
how many and when the firm plans to build each end item.
Aggregate Plan
(product groups)
MPS
(specific items)
The MPS translates the business plan, including forecast demand, into a production plan
using planned orders in a true multi-level optional component scheduling environment. Using
MPS helps avoid shortages, costly expediting, last minute scheduling, and inefficient
allocation of resources. Working with MPS allows businesses to consolidate planned parts,
produce master schedules and forecasts for any level of the Bill of Material (BOM) for any
type of part.
Example for mater production schedule for product A
Demand management Dates
2/5/12 3/5/12 4/5/12 5/5/12 7/5/12
Monthly demand for product A 4000
Working days in month 23
MPS daily demand for product A 174 174 174 174 174
MPS issues:
• Width of the time bucket
• Planning horizon
• Rolling plan
• Time fencing (frozen, moderately firm or flexible)
• Schedule freezing
Material requirements planning (MRP)
INPUTS OUTPUTS
Service parts Inventory
order forecast transaction data
Inventory
status file Materials Order changes
requirement Planned order
planning (MRP) schedule
Master
production
schedule Planning reports
Performance report
Bills of Exception
materials file reports
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10. Material requirements planning (MRP) is a production planning and inventory control system
used to manage manufacturing processes. Based on a master production schedule, a material
requirements planning (MRP) system:
 Creates schedules identifying the specific parts and materials required to produce end
items
 Determines exact numbers needed
 Determines the dates when orders for those materials should be released, based on
lead times
Approaches to processing MRP
• Net change approach: Only products that were active since last review are processed.
• Regenerative approach: All products are processed irrespective their activity status.
Gross to net logic in MRP
Net requirements = Gross requirements + allocated inventory + safety stock
– stock in hand + back orders
Lot sizing in MRP
 Economic order quantity
 Lot – for – lot
 Period – order – quantity
MRP II
 Goal: plan and monitor all resources of a manufacturing firm (closed loop):
• Manufacturing
• Marketing
• Finance
• Engineering
• Shop-floor control
 Simulation capability of the manufacturing system
Closed loop MRP Production planning
Master production scheduling
Material requirement planning
Capacity requirement planning
FEEDBACK
No
FEEDBACK
Realistic?
Yes
Execute 10
Capacity plan
Material plan

11. Just in Time
Just-in-time (JIT) purchasing is the purchase of goods or materials such that a delivery
immediately precedes demand or use. Companies moving toward JIT purchasing argue that
the cost of carrying inventories (in EOQ model) has been dramatically underestimated in the
past. The cost of placing a purchase order (in EOQ model) is also being re-evaluated.
Three factors are causing sizable reduction in the cost of placing a purchase order
1. Companies increasingly are establishing long-run purchasing arrangements.
2. Companies are using electronic links, such as the Internet, to place purchase orders
3. Companies are increasing the use of purchase order cards
Just-in-time (JIT) production systems take a “demand pull” approach in which goods are only
manufactured to satisfy customer orders.
Major features
1. Organizing production in manufacturing cells
2. Hiring and retaining multi-skilled workers
3. Emphasizing total quality management
4. Reducing manufacturing lead time and setup time
5. Building strong supplier relationships
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12. 05. Write short note on EOQ
Economic order quantity (EOQ) is the order quantity that minimizes total inventory holding
costs and ordering costs. It is one of the oldest classical production scheduling models. The
purpose of the EOQ model is to find that quantity to be ordered which minimizes the total
variable costs of inventory. Total variable costs are usually computed on an annual basis and
include two components, the costs of ordering and cost of holding the inventory.
Annual ordering cost is the number of orders placed times the marginal or incremental cost
incurred per order. This incremental cost includes several components such as the costs of
preparing the purchase order, paying the vendor's invoice, and inspecting and handling the
material when it arrives. It is difficult to estimate these components precisely. The EOQ is
not very much sensitive to errors in inputs.
The holding costs used in the EOQ should also be marginal in nature. Holding costs include
insurance, taxes, and storage charges, such as depreciation or the cost of leasing a
warehouse. The holding cost also includes the risk that inventory will spoil or become
obsolete before it can be used. Annual holding costs are usually computed as a fraction of
average inventory value.
EOQ applies only when demand for a product is constant over the year and each new order is
delivered in full when inventory reaches zero. There is a fixed cost for each order placed,
regardless of the number of units ordered. There is also a cost for each unit held in storage,
sometimes expressed as a percentage of the purchase cost of the item.
The optimal number of units to order is to be determined so that we minimize the total cost
associated with the purchase, delivery and storage of the product. The required parameters to
the solution are the total demand for the year, the purchase cost for each item, the fixed cost
to place the order and the storage cost for each item per year
Total cost
Annual cost
Holding cost
Ordering cost
EOQ Order quantity
Total Cost = purchase cost + ordering cost + holding cost
Underlying assumptions
1. The ordering cost is constant.
2. The rate of demand is known, and spread evenly throughout the year.
3. The lead time is fixed.
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13. 4. The purchase price of the item is constant i.e. no discount is available
5. The replenishment is made instantaneously; the whole batch is delivered at once.
6. Only one product is involved.
EOQ Formula
Total Cost = purchase cost + ordering cost + holding cost
Purchase cost: This is the variable cost of goods
Ordering cost: This is the cost of placing orders
Holding cost: the average quantity in stock (between fully replenished and empty) is Q/2
D= Annual demand (units) Total cost = D C + S x (D/Q) + (Q/2) x I x C
C= Cost per unit ($)
Q= Order quantity (units)
S= Fixed Cost per order ($) Take the 1st derivative:
I = Holding cost (%)
H= Holding cost ($) = I x C d(TC)/d(Q) = (I x C) / 2 - (D x S) / Q²
To optimize: set d(TC)/d(Q) = 0
Number of Orders =D/Q DS/ Q² = IC / 2
Ordering costs ($) = S x (D / Q)
EQ²/DS = 2 / IC
Average inventory
units = Q/2 Q²= (DS x 2 )/ IC
($) = (Q / 2) x C
Cost to carry
average inventory = (Q / 2) x I x C
Holding cost ($) = (Q /2) x H
Purchase cost ($) =DC
EOQ is the function of annual demand (D), cost per order (S) and holding cost (H or IC)
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14. 06. Write short note on EOQ with quantity discount
Quantity discounts are the price reductions designed to induce large orders. The goal of the
buyer is to select the order quantity that will minimize the total cost.
Economic order quantity (EOQ) is the order quantity that minimizes total inventory holding
costs and ordering costs. It is one of the oldest classical production scheduling models. The
purpose of the EOQ model is to find that quantity to be ordered which minimizes the total
variable costs of inventory. Total variable costs are usually computed on an annual basis and
include two components, the costs of ordering and cost of holding the inventory.
Total Cost = purchase cost + ordering cost + holding cost
The EOQ with quantity discount is worked out in two steps
Step 1: Calculate EOQ. If this amount can be purchased at the lowest price, you have found
the quantity that minimizes the equation. If not, proceed to step 2.
Step 2: Compare total cost at the EOQ quantity with total costs at each price break above
the EOQ.
.
Example
Total cost Rage 1 Rage 2 Rage 3
Cost per unit = C1 Cost per unit = C2 Cost per unit = C3
TC3
TC1
TC2
EOQ of EOQ of EOQ of
Range 1 Range 2 Range 3 Reorder quantity
TC1 = D C1 + S (D/Q) + (Q/2) (I C1)
TC2 = D C2 + S (D/Q) + (Q/2) (I C2)
TC3 = D C3 + S (D/Q) + (Q/2) (I C3)
TC2< TC1< TC3
Hence, select ‘EOQ of range 2’ as reorder quantity
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15. 07. Write short note on safety stock
Safety stock (also called buffer stock) is a term used by logisticians to describe a level of
extra stock that is maintained to mitigate risk of stock outs (shortfall in raw material or
packaging) due to uncertainties in supply and demand. Adequate safety stock levels permit
business operations to proceed according to their plans.
Production with and without safety stock
Production without safety stock Production with safety stock
(a) Normal production
Quantity
Max order level Quantity Max order level
Reorder level Reorder level
Safety stock
Time
Lead Time
Time
Lead Time
(b) Unexpected increased production at or beyond reorder level (during lead time)
Quantity
Quantity
Max order level Max order level
Reorder level Reorder level
Safety stock
Time
Lead Time
Time
Lead Time
Production continued utilizing safety stock
No production
A low level of safety stock can lead to a stock out. On the other hand a high level of safety
stock unnecessarily ties up capital. Therefore we need to determine the optimum level of
safety stock, which should neither be low nor high.
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16. Cost of safety stock
Safety stock involves two types of costs:
1. Carrying cost of safety stock (CC)
2. Stock out cost (SC)
Carrying cost of safety stock is inversely proportional to stock out cost. Research shows that
the total cost of safety stock is minimum only when
Carrying cost of safety stock = stock out cost
Reducing safety stock
Safety stock is used as a buffer to protect organizations from stock outs caused by inaccurate
planning or poor schedule adherence by suppliers. As such, its cost (in both material and
management) is often seen as a drain on financial resources that results in reduction
initiatives. In addition, time sensitive goods such as food, drink, and other perishable items
could spoil and go to waste if held as safety stock for too long. Various methods exist to
reduce safety stock; these include better use of technology, increased collaboration with
suppliers, and more accurate forecasting. In a lean supply environment, lead times are
reduced, which can help minimize safety stock levels thus reducing the likelihood and impact
of stock outs. Due to the cost of safety stock, many organizations opt for a service level led
safety stock calculation; for example, a 95% service level could result in stock outs, but is at
a level that is satisfactory to the company. The lower the service level, the lower the
requirement for safety stock.
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17. 08. Write short note on MRP (material requirement planning)
Material Requirements Planning (MRP) is a computer-based production planning and
inventory control system. MRP is concerned with both production scheduling and inventory
control. It is a material control system that attempts to keep adequate inventory levels to
assure that required materials are available when needed. MRP is applicable in situations of
multiple items with complex bills of materials. MRP is not useful for job shops or for
continuous processes that are tightly linked.
The major objectives of an MRP system are:
1. Ensure the availability of materials, components, and products for planned production and
for customer delivery.
2. Maintain the lowest possible level of inventory
3. Plan manufacturing activities, delivery schedules, and purchasing activities.
MRP is especially suited to manufacturing settings where the demand of many of the
components and subassemblies depend on the demands of items that face external demands.
Demand for end items is independent. In contrast, demand for components used to
manufacture end items depend on the demands for the end items. The distinctions between
independent and dependent demands are important in classifying inventory items and in
developing systems to manage items within each demand classification.
The three major inputs of an MRP system are the master production schedule, the product
structure records, and the inventory status records. Without these basic inputs the MRP
system cannot function. The demand for end items is scheduled over a number of time
periods and recorded on a master production schedule (MPS). The master production
schedule expresses how much of each item is wanted and when it is wanted. The MPS is
developed from forecasts and customer orders for end items, safety stock requirements, and
internal orders. MRP takes the master schedule for end items and translates it into individual
time-phased component requirements. The product structure records, also known as bill of
material records (BOM), contain information on every item or assembly required to produce
end items. Information on each item, such as part number, description, quantity per assembly,
next higher assembly, lead times, and quantity per end item, must be available.
The inventory status records contain the status of all items in inventory, including on hand
inventory and scheduled receipts. These records must be kept up to date, with each receipt,
dis-bursement, or withdrawal documented to maintain record integrity. MRP will determine
from the master production schedule and the product structure records the gross component
requirements; the gross component requirements will be reduced by the available inventory
as indicated in the inventory status records.
Dealing with Uncertainty in MRP
There are several sources of uncertainty that we have ignored so far. These include
uncertainty in the quantity demanded (forecast errors) and the quantity supplied (yield
losses), and uncertainty in the timing of demand and the timing of supply (random lead
times). Many MRP systems cope with uncertainty by inflating lead times (inducing safety
time), by expediting orders, and by shifting priorities of shop and vendor orders. Another
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18. way of protecting against uncertainty is to carry safety stock for end items with random
demand, and to carry safety stock of items produced at bottleneck operations.
Shortcomings of MRP
Capacity
MRP expects the lead time to be constant regardless of how much work has been released
into the Production system, so it is implicitly assuming infinite capacity. This can
create problems when production levels are at or near capacity. One way to address this
problem is to make sure that the MPS is capacity feasible. Rough-cut capacity planning
(RCCP) attempts to do this by checking the capacity of a few critical resources. RCCP
makes use of the bill of resources (BOR) for each item on the MPS. The BOR specifies the
number of hours required at each critical resource to build a particular end item and its
components, and then aggregates the number of hours required at each critical resource over
the end items in the MPS. RCCP then checks whether the available resources are enough to
cover the MPS on each time bucket. Notice that RCCP does not perform time offsets, so the
calculation of the number of hours required has to be done with time buckets that are large
enough so that parts and their components can all be completed within a single time bucket.
This usually makes RCCP an optimistic estimation of what can be done. Advanced MRP
systems provide more detailed capacity analysis proposing alternative production schedules
when the current plan is not feasible.
Long Lead Times
There are many pressures to increase planned lead times in an MRP system. MRP
uses constant lead times when, in fact, actual lead times vary considerably. To
compensate, planners typically choose pessimistic estimates. Long lead times lead to large
work-in-process (WIP) inventories.
Nervousness
MRP is typically applied in a rolling horizon basis. As customer orders firm up, and forecasts
become better, a new MPS is fed to MRP which produces updated planned order releases that
may be very different form the original. Even small changes in the MPS can result in large
changes in planned order releases. A small decrease in demand causes a formerly feasible
MRP plan to become infeasible.
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19. 09. Explain in detail production planning and control process
Production Planning is a process to develop tactical plans based on setting the overall level
of manufacturing output (production plan) and other activities to best satisfy the current
planned levels of sales (sales plan or forecasts), while meeting general business objectives of
profitability, productivity, competitive customer lead times, and so on, as expressed in the
overall business plan. The sales and production capabilities are compared, and a business
strategy that includes a sales plan, a production plan, budgets, pro forma financial statements,
and supporting plans for materials and workforce requirements, and so on, is developed. One
of its primary purposes is to establish production rates that will achieve management’s
objective of satisfying customer demand by maintaining, raising, or lowering inventories or
backlogs, while usually attempting to keep the workforce relatively stable. Because this plan
affects many company functions, it is normally prepared with information from marketing
and coordinated with the functions of manufacturing, sales, engineering, finance, materials,
and so on.
Advanced Planning and Scheduling (APS)
APS is the techniques that deal with analysis and planning of logistics and manufacturing
during short, intermediate and long-term time periods. APS describes any computer program
that uses advanced mathematical algorithms or logic to perform optimization or simulation on
finite capacity scheduling, sourcing, capital planning, resource planning, forecasting, demand
management, and others. These techniques simultaneously consider a range of constraints
and business rules to provide real-time planning and scheduling, decision support, available-
to-promise, and capable-to-promise capabilities. APS often generates and evaluates multiple
scenarios. Management then selects one scenario to use as the “official plan.”
Components of APS
• Demand Planning,
• Production Planning,
• Production Scheduling,
• Distribution Planning, and
• Transportation Planning.
Production planning is the function of establishing an overall level of output, called the
production plan. The process also includes any other activities needed to satisfy current
planned levels of sales, while meeting the firm's general objectives regarding profit,
productivity, lead times, and customer satisfaction, as expressed in the overall business plan.
The production schedule is derived from the production plan; it is a plan that authorized the
operations function to produce a certain quantity of an item within a specified time frame. In
a large firm, the production schedule is drawn in the production planning department.
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20. 10. Explain in detail MPS (master production scheduling)
A Master Production Schedule or MPS is the plan that a company has developed for
production, inventory, staffing, etc. It sets the quantity of each end item to be completed in
each week of a short-range planning horizon. A Master Production Schedule is the master of
all schedules. It is a plan for future production of end items.
Process in MPS system
INPUTS OUTPUTS
Forecast Demand
Production Costs Amounts to be Produced
Inventory Costs Staffing Levels
Customer Orders Quantity Available to Promise
Inventory Levels MPS Projected Available Balance
Supply
Lot Size
Production Lead Time
Capacity
The Master Production Schedule gives production, planning, purchasing, and top
management the information needed to plan and control the manufacturing operation. The
application ties overall business planning and forecasting to detail operations through the
Master Production Schedule. The Master Production Schedule will drive detailed material
and production requirements in the Material Requirements Planning module.
The master production schedule (MPS) is a link between the firm’s broad strategies and
tactical plans that enables the firm to achieve its goals. The MPS provides essential
information for functional areas such as operations, marketing, and finance. In this
supplement, we discuss the master production scheduling process, the need for functional
coordination, the way to develop an MPS, the information that an MPS provides to assist in
negotiating delivery dates, and the managerial considerations for establishing and stabilizing
the MPS.
By using several variables as inputs the MPS will generate a set of outputs used for decision
making. Inputs may include forecast demand, production costs, inventory costs, customer
orders, inventory levels, supply, lot size, production lead time, and capacity. Inputs may be
automatically generated by an ERP system that links a sales department with a production
department. For instance, when the sales department records a sale, the forecast demand
may be automatically shifted to meet the new demand. Inputs may also be inputted
manually from forecasts that have also been calculated manually. Outputs may include
amounts to be produced, staffing levels, quantity available to promise, and projected
available balance. Outputs may be used to create a Material Requirements Planning (MRP)
schedule.
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21. 11. Explain in detail short term scheduling process and techniques
Scheduling is an important tool for manufacturing and engineering, where it can have a
major impact on the productivity of a process. In manufacturing, the purpose of scheduling
is to minimize the production time and costs, by telling a production facility when to make,
with which staff, and on which equipment. Production scheduling aims to maximize the
efficiency of the operation and reduce costs.
Production scheduling tools greatly outperform older manual scheduling methods. These
provide the production scheduler with powerful graphical interfaces which can be used to
visually optimize real-time work loads in various stages of production, and pattern
recognition allows the software to automatically create scheduling opportunities which
might not be apparent without this view into the data. For example, an airline might wish to
minimize the number of airport gates required for its aircraft, in order to reduce costs, and
scheduling software can allow the planners to see how this can be done, by analyzing time
tables, aircraft usage, or the flow of passengers.
Short term scheduling concerns with the allocation of CPU time to processes in order to
meet some pre-defined system performance objectives. The definition of these objectives
(scheduling policy) is an overall system design issue, and determines the ``character'' of the
operating system from the user's (i.e. the buyer's) point of view, giving rise to the traditional
distinctions among ``multi-purpose, time shared'', ``batch production'', ``real-time'' systems,
and so on.
The main types of scheduling process and techniques include:
Work centre loading
Job sequencing
Work centre loading
Work centre loading is the assignment of jobs to work or processing centers. The operation
managers assign the job to work centres so that cost, idle time or completion is kept to
minimum. The forms of work centre loading are
Oriented to capacity
Assign the specific job to work centres
Job sequencing
Job sequencing is the arrangement of task required to be carried out sequentially. Priority
rules for the job sequencing are derived based on the assumption that job setup cost and
time is independent of process time. Job time include setup and processing time. Priority
rules aim at minimizing completion time, number of jobs in a system and job lateness.
Rules establish maximum facility utilization.
**************
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