How to do Value Stream Mapping – Part 3
This is a video by LEANLAB and it’s available on www.leanvlog.com
The Process Box
In this video, we teach you the second element to draw in your value stream map: The basic production process with the process box.
The process box indicates a process where the material flow. Do you have to draw every single process? No! The rule of thumb is to draw 1 process box wherever the processes are disconnected, and the material flow stops. If a detailed process map is necessary, you could zoom in later on.
The process box has the simple form of a rectangle with a title on the top. Walking into the shop during the value stream mapping, you need to draw the box and collect data that will be the starting point for the future state. So, for each process box, you need to connect a data box. The data box is a simple list of information you think is necessary.
Here there is a list to get started.
- Cycle Time The time between two parts coming off the process.
- Change Over Time The time to switch from Product A to Product B
- Number of People It is the number of people you need “MINUMUM” to operate the process.
- Available Time How many minutes is the machine available in one shift for the Value Stream you are mapping?
- Uptime How many minutes is the machine not stopped for maintenance?
- Scrap Rate How many parts do you scrap in percentage?
The list of information will be richer the more you draw value stream maps. Are you ok so far?
Let us move to another important symbol: Inventory. As you walk the value stream, you will find places where the inventory is accumulated. You have to track it on the value stream with a warning triangle with an “I” in the middle and the number of pieces you see on the floor. Ok. Once you have done this walk, you should have a Value Stream Map that should appear as follow.
Element 1 – The Customer Demand
Element 2 – The process flow with the inventory icons and data boxes.
In the next video, I will explain you the 3rd element of the Value Stream Map: The Material Flow.