The Climate Change & COP21

Atención! Minerales en Extinción / Watch out! Mineral in Extinction

The Application of Value Stream Mapping in the Production Systems

VALUE STREAM MAPPING  

Planning tool to optimize results of eliminating waste, the “value” is what the customer is buying 

THE FIVE SIMPLE PRINCIPLES

• Specify value from the standpoint of end customer 
• Identify the value stream for each product family 
• Make the product flow 
• So the customer can pull 
• As you manage toward perfection

TIMELINE CALCULATION 

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

CUSTOMER DEMAND AND TAKT TIME CALCULATION 

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

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:

INVENTORY TIME 

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

Timeline peak

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.

Timeline 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.