Ch5 process analysis


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Ch5 process analysis

  1. 1. 1 Process Analysis
  2. 2. 2 OBJECTIVES • Process Analysis • Process Flowcharting • Types of Processes • Process Performance Metrics
  3. 3. 3 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
  4. 4. 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 4
  5. 5. 5 PROCESS ANALYSIS Standard Symbols used for Flowcharting Symbol Activity Operation Transportation or Movement Inspection Delay/Temporary Storage Definition of Activity Modification of an object Change in location of an Item Examination of an Object (Qlty/Qty parameters) Retention of an Object in a location awaiting next activity
  6. 6. 6 Decision Point (Awaiting decision on further Action) Storage Combined Activity Location awaiting next activity Items in stored condition (no unauthorized removal) Two activities occur simultaneously
  7. 7. • 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 (unit item) • • the elapsed time between starting and completing a job (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 (for the m/c) is the time required to prepare a m/c to produce an item 7
  8. 8. • Operation time is the sum of set-up time and runtime for a batch of parts that are run on a m/c (for the Batch) • Thro’put time ( for the Unit) the time that the unit spends actually being worked plus the time spent waiting in aQ • Thro’put Rate • Value Added time (for the Batch) (for the unit) • Thro’put Ratio is the Output rate that the process is expected to produce over a period of time the time in which useful work is actually being done on the unit Process Velocity : the ratio of the total thro’put time to the value added time 8
  9. 9. 9 • Make-to-order • Make-to-stock • Hybrid (Either Unit or Batch) (Either Unit or Batch) (Unit or Batch ) A process that is activated only in response to an actual order A process that produces standard products that are stored in finished Goods Inventory : the product is quickly delivered to the customer Combines the feature of both make-to-order and make-to-stock (A generic product is made and customised in a final process to meet actual orders)
  10. 10. Make-to-Order customer Customer Order Product Production
  11. 11. Make-to-Stock Forecast orders customer Production Customer Order Product Finished Goods Inventory Product
  12. 12. Assemble-to-Order Forecast orders customer Production of Subassemblies Customer order Product Assembly of the Order Subassembly Inventory of Subassemblies
  13. 13. 13  Efficiency  Productivity  Utilization  Little’s Law Actual Output Standard Output Output Input Time activated Time available (definition as follows) Thro’put time = Work-in-Proccess Thro’put Rate
  14. 14. 14 Example: Flowchart of Student Going to School Go to school today? No Abstain Yes Drive to school Walk to class
  15. 15. 15 Types of Processes Single-stage Process Stage 1 Multi-stage Process Stage 1 Stage 2 Stage 3
  16. 16. 16 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
  17. 17. 17 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
  18. 18. Process Performance Metrics 18  Operation time = Setup time + Run time  Throughput time = Average time for a unit to move through the system  Velocity = Throughput time Value-added time
  19. 19. Process Performance Metrics (Continued)  Cycle time = Average time between completion of units  Throughput rate = 1 . Cycle time  Efficiency = Actual output Standard Output 19
  20. 20. Process Performance Metrics (Continued)  Productivity = Output Input  Utilization = Time Activated Time Available 20
  21. 21. Cycle Time Example 21 Suppose you had to produce 600 units in 80 Suppose you had to produce 600 units in 80 hours to meet the demand requirements of a hours to meet the demand requirements of a product. What is the cycle time to meet this product. What is the cycle time to meet this demand requirement? demand requirement? Answer: There are 4,800 minutes (60 Answer: There are 4,800 minutes (60 minutes/hour x 80 hours) in 80 hours. So the minutes/hour x 80 hours) in 80 hours. So the average time between completions would have average time between completions would have to be: Cycle time = 4,800/600 units = 8 minutes. to be: Cycle time = 4,800/600 units = 8 minutes.
  22. 22. 22 Process Throughput Time Reduction  Perform activities in parallel  Change the sequence of activities  Reduce interruptions
  23. 23. 23 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 purchase c. Time it takes for an instructor to grade an exam d. Time it takes to complete an automobile e. All of the above Answer: e. All of the above
  24. 24. 24 Question Bowl Which of the following are used as symbols in a Process Flowchart? a. Decision points b. Blocking c. Starving d. Bottleneck e. All of the above Answer: a. Decision points (A diamond shaped symbol.)
  25. 25. 25 Question Bowl Which type of process is configured as follows? 1 2 Single-stage process b. Multi-stage process c. Make-to-order process d. Make-to-stock process e. All of the above Answer: b. Multi-stage process a. 3
  26. 26. 26 Question Bowl a. b. c. d. e. 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? Buffering Blocking Starving Bottleneck All of the above Answer: c. Starving
  27. 27. 27 Question Bowl a. b. c. d. e. 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? Single-stage process Multi-stage process Make-to-order process Make-to-stock process All of the above Answer: c. Make-to-order process
  28. 28. 28 Question Bowl a. b. c. d. e. 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? 75 minutes 110 minutes Only 45 minutes 65/45 minutes or 1.44 hours 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)
  29. 29. 29 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 Answer: c. 112.5% Efficiency? (Ratio of actual a. 88.8% performance/expected performance, b. 100% or (27/24) x 100 = 110 minutes) c. d. e. 112.5% Well over 150% Can not computed on the information given.
  30. 30. 30 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 Product The setup and runtimes for each component are given below:- Component Setup / Changeover Time Run Time / Unit A 5 min 0.2 min B 10 min 0.1 min 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)
  31. 31. 31 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
  32. 32. 32  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