Presentation on theme: "QUAN 6610 Flow Time Analysis (T)"— Presentation transcript:
1 QUAN 6610 Flow Time Analysis (T) Chapter 4Flow Time Analysis (T)I = R x TChapter 4Flow-Time AnalysisChapter 5Flow Rate and Capacity AnalysisChapter 6Inventory AnalysisBased on Anupindi, et al, MBPF (2e)Flow Time
2 Process Flow Time Flow time affects delivery response time. Short flow times reduce the inventory.Shorter flow time in the development process enables a company to get to market quicker giving a competitive advantage.Can minimize production start to gain market information, avoid product obsolescence and minimize inventory.Results in fast feedback and correction of quality problems.Flow time is an integrative measure of overall process performance.
3 A process flowchart is a graphical representation of the five process elements: inputs and outputs, flow units, network of activities, resources allocated to activities and information structure.31246785Direct measurement and indirect measurement method.Example 4.2
4 Determining the critical path 4.3 Theoretical Flow TimeDetermining the critical pathTheoretical flow time is the minimum amount of time required for processing a typical flow unit without any waiting.Example 4.4
5 Example 4.5Flow time = Theoretical flow time + Waiting time
6 Value-adding and Non-value-adding Flow time = value-adding flow time + non-value-adding flow timeRework, Visits and Work ContentExample 4.6 | Table 4.4Work content = activity time * average number of visits
7 Flow time efficiency = Theoretical flow time / Average flow time QUAN 6610Flow time efficiencyX-ray VOH Example 4.7Flow time efficiency = Theoretical flow time / Average flow timeMost time inefficiency comes from waiting: E.g.: Flow Times in White Collar ProcessesFlow Time
8 Levers for Reducing Flow Time QUAN 6610Levers for Reducing Flow TimeDecrease the work content of critical activitieswork smarterwork fasterdo it right the first timechange product mixMove work content from critical to non-critical activitiesto non-critical path or to ``outer loop’’Reduce waiting time.Flow Time
9 QUAN 6610Value Added vs. NVA Time“Just track any work items as it flows through the process and classify the time into one of three categories: (1) value-added work, (2) waste that is required for business reasons, and (3) delays/waste. Then draw a timeline and mark off the time segments for each of these categories. In the example shown, the value-added work (shaded above the centerline) shows the buyer in this purchasing organization is only working the order for 14 minutes of the 4 day cycle. The majority of the time, delineated by white space, is idle queueing time.”Lean Six Sigma by George, et al.Process Capacity
10 QUAN 6610Source: Lean Learning Center, Value Stream Mapping Course Notes.Process Capacity
11 QUAN 6610Source: Lean Learning Center, Value Stream Mapping Course Notes.Process Capacity
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