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Chapter 4. I = R x T. Flow Time Analysis (T). Chapter 4 Flow-Time Analysis. Chapter 5 Flow Rate and Capacity Analysis. Chapter 6 Inventory Analysis. Based on Anupindi , et al, MBPF (2e). Process Flow Time. Flow time affects delivery response time.
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Chapter 4 I = R x T Flow Time Analysis (T) Chapter 4 Flow-Time Analysis Chapter 5 Flow Rate and Capacity Analysis Chapter 6 Inventory Analysis Based on Anupindi, et al, MBPF (2e)
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 5 7 8 1 2 4 6 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. Direct measurement and indirect measurement method. Example 4.2
4.3 Theoretical Flow Time Determining the critical path Theoretical flow time is the minimum amount of time required for processing a typical flow unit without any waiting. Example 4.4
Example 4.5 Flow time = Theoretical flow time + Waiting time
Value-adding and Non-value-adding Flow time = value-adding flow time + non-value-adding flow time Rework, Visits and Work Content Example 4.6 | Table 4.4 Work content = activity time * average number of visits
Flow time efficiency Most time inefficiency comes from waiting: E.g.: Flow Times in White Collar Processes X-ray VOH Example 4.7 Flow time efficiency = Theoretical flow time / Average flow time
Levers for Reducing Flow Time • Decrease the work content of critical activities • work smarter • work faster • do it right the first time • change product mix • Move work content from critical to non-critical activities • to non-critical path or to ``outer loop’’ • Reduce waiting time.
Value 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.
Source: Lean Learning Center, Value Stream Mapping Course Notes.
Source: Lean Learning Center, Value Stream Mapping Course Notes.
