Value stream map calculations

Value stream maps calculate values in the timeline, the timeline summary box, and the customer demand box.

Timeline calculations

As you add data to process and inventory shapes, the value stream map displays a timeline. The timeline shows the impact of cycle time and inventory on your process.

Inventory time

Inventory time values for inventory shapes appear on the peaks of the timeline.

For each inventory shape, if you do not enter a value for inventory time in the task pane, then the timeline calculates inventory time. The timeline calculates inventory time based on the type of inventory the shape represents.

Type of inventory Calculation
Process step inventory inventory time = (inventory × CT) / (# of operators × A × B × uptime %)
When:
  • CT = the highest value from the process shape to the right of the inventory shape
  • A = First pass yield, or 1 - defect %, whichever value is lower
  • B = Machine availability %, or operator availability %, whichever value is lower
Finished goods inventory inventory time = (inventory × takt time) / (# of operators × A × B × uptime %)
When:
  • A = First pass yield, or 1 - defect %, whichever value is lower
  • B = Machine availability %, or operator availability %, whichever value is lower

Cycle time

Cycle time values for process shapes appear in the troughs of the timeline. The timeline displays cycle time at the top of the trough and value added cycle time at the bottom of the trough.
For each process shape, you can enter any combination of cycle time (CT), value added cycle time (VA CT), and non-value added cycle time (NVA CT). The value stream map calculates cycle times based on the following equation:
  • cycle time (CT) = value added cycle time (VA CT) + non-value added cycle time (NVA CT)

If the values that you enter for CT, VA CT, and NVA CT do not fit this equation, the value stream map calculates and displays cycle times as follows:

Scenario Example of user-entered values Timeline display

CT = VA CT

  • CT = 2 min
  • VA CT = 2 min

VA CT appears in the trough

CT < VA CT

  • CT = 1 min
  • VA CT = 2 min

VA CT appears in the trough

CT < NVA CT

  • CT = 1 min
  • VA CT = not entered
  • NVA CT = 3 min

NVA CT (top); 0 (bottom)

CT < (VA CT + NVA CT)

  • CT = 2 min
  • VA CT = 3 min
  • NVA CT = 1 min

VA CT + NVA CT (top); VA CT (bottom)

Timeline summary box calculations

A value stream map keeps a running total of the timeline data in the timeline summary box.
Total Cycle Time
The sum of the cycle time values, either entered or calculated, for the process shapes.
Total VA Cycle Time
The sum of the value added cycle time values, either entered or calculated, for the process shapes.
Total NVA Cycle Time
The sum of the non-value added cycle time values, either entered or calculated, for the process shapes.
Lead Time
The sum of the inventory time values for the inventory shapes, plus the sum of the cycle time values for the process shapes.
WIP Time
The sum of the inventory time values for the inventory shapes, excluding raw materials inventory and finished goods inventory, plus the sum of the cycle time values for the process shapes.
Total Distance
The sum of the distance values for the process and inventory shapes.

Customer demand and takt time calculations

The value stream map calculates takt time based on what you enter for customer demand and facility data on the Map Calculations task pane. The values appear in the customer demand and takt time box on the map.
Tip

Choose View > Customer demand and takt time to show or hide the display on the map.

Customer Demand
The number of product units or service units that a customer requires in a certain period of time.
Takt Time
Uses the following calculation:
Hours/Day
Uses the following calculation:
By using this site you agree to the use of cookies for analytics and personalized content.  Read our policy