Ch5 process analysis
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Transcript of Ch5 process analysis
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Process Analysis
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• Process Analysis
• Process Flowcharting
• Types of Processes
• Process Performance Metrics
OBJECTIVES
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Process Analysis Terms
Process: Is any part of an organization that takes inputs and transforms them into outputs
Cycle Time: Is the average successive time between completions of successive units
Utilization: Is the ratio of the time that a resource is actually activated relative to the time that it is available for use
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Process Flowcharting Defined
Process flowcharting is the use of a diagram to present the major elements of a process
The basic elements can include tasks or operations, flows of materials or customers, decision points, and storage areas or queues
It is an ideal methodology by which to begin analyzing a process
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PROCESS ANALYSISStandard Symbols used for Flowcharting
Symbol Activity Definition of Activity
Operation Modification of an object
Transportation or Movement
Change in location of an Item
Inspection
Examination of an Object (Qlty/Qty parameters)
Delay/Temporary Storage
Retention of an Object in a location awaiting next activity
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Decision Point (Awaiting decision on further Action)
Location awaiting next activity
Storage Items in stored condition (no unauthorized removal)
Combined Activity
Two activities occur simultaneously
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PROCESS ANALYSIS – Key Terms
• What is a process?A process is any part of an organization that takes Inputs and transforms them into Outputs
• Cycle time the elapsed time between starting and completing a job
(unit item) (Average time between completion of units)
• Run time is the time required to produce a batch of parts
(for the batch) (this is calculated by multiplying the time required to
produce each unit by the batch size)
• Set-up time is the time required to prepare a m/c to produce an item
(for the m/c)
8• Operation time is the sum of set-up time and runtime for a batch
(for the Batch) of parts that are run on a m/c
• Thro’put time the time that the unit spends actually being ( for the Unit) worked plus the time spent waiting in a Q
• Thro’put Rate is the Output rate that the process is expected to (for the Batch) produce over a period of time
• Value Added time the time in which useful work is actually being
(for the unit) done on the unit
• Thro’put Ratio Process Velocity :
the ratio of the total thro’put time to the value added
time
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• Make-to-order A process that is activated only in response to an (Either Unit or actual order Batch)
• Make-to-stock A process that produces standard products that are (Either Unit or stored in finished Goods Inventory : the product is Batch) quickly delivered to the customer
• Hybrid Combines the feature of both make-to-order and (Unit or Batch ) make-to-stock
(A generic product is made and customised in a final process to meet actual orders)
Make-to-Order
customer
Production
Product
Customer Order
Make-to-Stock
customer
Forecast orders
Production
Finished Goods Inventory
Product
Customer OrderProduct
Assemble-to-Order
customer
Forecast orders
Production of Subassemblies
Inventory
of Subassemblies
Customer order
ProductAssembly
of the Order
Subassembly
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Efficiency Actual Output
Standard Output
Productivity Output
Input
Utilization Time activated
Time available
Little’s Law Thro’put time = Work-in-Proccess
(definition as follows) Thro’put Rate
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Example: Flowchart of Student Going to School
Yes
No
Abstain
Go to school today?
Walk to class
Drive to school
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Types of Processes
Single-stage Process
Stage 1
Stage 1 Stage 2 Stage 3
Multi-stage Process
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Other Process Terminology (Continued)
Bottleneck– Occurs when the limited capacity of a process
causes work to pile up or become unevenly distributed in the flow of a process
– If an employee works too slow in a multi-stage process, work will begin to pile up in front of that employee. In this case the employee represents the limited capacity causing the bottleneck.
Pacing– Refers to the fixed timing of the movement of
items through the process
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Other Types of Processes
Make-to-order
– Activated only in response to an actual order
– Both work-in-process and finished goods
inventory kept to a minimum
Make-to-stock
– Process activated to meet expected or
forecast demand
– Customer orders are served from target
stocking level
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Process Performance Metrics
Operation time = Setup time + Run time
Throughput time = Average time for a unit tomove through the
system
Velocity = Throughput time
Value-added time
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Process Performance Metrics (Continued)
Cycle time = Average time betweencompletion of units
Throughput rate = 1 . Cycle time
Efficiency = Actual output Standard Output
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Process Performance Metrics (Continued)
Productivity = Output
Input
Utilization = Time Activated
Time Available
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Cycle Time Example
Suppose you had to produce 600 units in 80 hours to meet the demand requirements of a product. What is the cycle time to meet this demand requirement?
Suppose you had to produce 600 units in 80 hours to meet the demand requirements of a product. What is the cycle time to meet this demand requirement?
Answer: There are 4,800 minutes (60 minutes/hour x 80 hours) in 80 hours. So the average time between completions would have to be: Cycle time = 4,800/600 units = 8 minutes.
Answer: There are 4,800 minutes (60 minutes/hour x 80 hours) in 80 hours. So the average time between completions would have to be: Cycle time = 4,800/600 units = 8 minutes.
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Process Throughput Time Reduction
Perform activities in parallel
Change the sequence of activities
Reduce interruptions
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Question Bowl
Which of the following are possible examples of “cycle times”?
a. Time for each television to come off an assembly line.
b. Time it takes for a stock purchasec. Time it takes for an instructor to grade
an examd. Time it takes to complete an automobilee. All of the above
Answer: e. All of the above
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Question Bowl
Which of the following are used as symbols in a Process Flowchart?
a. Decision pointsb. Blockingc. Starvingd. Bottlenecke. All of the above
Answer: a. Decision points (A diamond shaped symbol.)
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Question Bowl
Which type of process is configured as follows?
a. Single-stage processb. Multi-stage processc. Make-to-order processd. Make-to-stock processe. All of the above
Answer: b. Multi-stage process
1 2 3
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Question Bowl
When an assembly line employee is waiting
for a unit of work to come down the line so
they can stop being idle and get back to
work, it is an example of which of the
following process terms?
a. Buffering
b. Blocking
c. Starving
d. Bottleneck
e. All of the above
Answer: c. Starving
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Question Bowl
When a company waits until they have an order for their product in hand before beginning any production for that order, we can characterize their operation as which of the following processes?
a. Single-stage processb. Multi-stage processc. Make-to-order processd. Make-to-stock processe. All of the above
Answer: c. Make-to-order process
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Question Bowl
If the Run Time for a batch of parts is 45 minutes on a machine, and the Setup Time is 65 minutes, which of the following is the Operation Time?
a. 75 minutesb. 110 minutesc. Only 45 minutesd. 65/45 minutes or 1.44 hourse. Can not be computed on the data above
Answer: b. 110 minutes ( Operation Time is the sum of Run Time and Setup Time, or 65 + 45 = 110 minutes)
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Question Bowl
If the standard expected phone calls for a
telephone marketers is 24 per hour, and one
telephone marketer did 27 per hour, which of
the following can be used to describe their
Efficiency?
a. 88.8%
b. 100%
c. 112.5%
d. Well over 150%
e. Can not computed on the information given.
Answer: c. 112.5% (Ratio of actual performance/expected performance, or (27/24) x 100 = 110 minutes)
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Solved Problems – OPERATIONS MANAGEMENT(Class of 2010)
Q5. A processor makes 2 components, A and B, which are then packed together as final product (each product sold contains one A and one B). The processor can do only one component at a time: either it can make As or it can make Bs. There is a setup time when switching from A to B
Current plans are to make 100 units of component A, then 100 units of component B, and then 100 units of A and 100 units of B to be packed to be supplied as 100 units of Final ProductThe setup and runtimes for each component are given below:-
Assume that packaging of 2 components is totally automated and takes only 2 seconds / unit of the final product. The packaging time is small enough that you can ignore it. What is the average hourly output in terms of no. of units of packaged products (which includes 1 of A and 1 of B)
Component Setup / Changeover Time
Run Time / Unit
A 5 min 0.2 min
B 10 min 0.1 min
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Answer. In order to make final goods, we have to assemble both component A and component B.
So, let us find out the final operation time for both the components :-
Component A
Operation Time = Setuptime + Runtime (for batch)
= 5 + [ (0.2 × 100)]
= 25 minutes
Component B
Operation Time = Setuptime + Runtime (for batch)
= 10 + [ (0.1 × 100)]
= 20 minutes
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So, Total Operation Time for 100 nos. of Finished Products ( Excluding Packaging Time)
= 25 + 20
= 45 minutes / 100 pcs
Now, to find out Average output per Hour
In 45 minutes - - - - - - 100 nos
60 minutes - - - - - - ?
= 60 × 100 = 133.34 units
45
Therefore Average Output per Hour = 134 units