Value Stream mapping

What is Value Stream mapping

Value Stream Mapping (VSM) is a lean manufacturing tool and technique used to analyze, design, and manage the flow of materials and information required to produce a product or service, from the time customers place an order up to delivery of that product or service.

It is a high-level big picture view of the entire value adding process that is being analyzed which can highlight information and material flow step by step allowing the identification of delays, issues, wastes and value adding steps in a much user-friendly way.

Value Stream Mapping originated in the Toyota Production System as a way to improve efficiency and eliminate waste. It was developed in the 1950s by Taiichi Ohno, who is considered the father of the Toyota Production System. Ohno believed that eliminating waste was the key to increasing efficiency and reducing costs.

How does Value Stream Mapping work?

VSM involves mapping the entire value stream of a process, including all the steps involved in producing a product, from the raw materials to the finished product. The map should also include information on the time required for each step, the number of people involved, and the inventory levels at each stage of the process together with any information or communication loops from the customer the different areas of the company or process.

Once the map is created, the team can analyze the process and identify areas of waste. This can include overproduction, waiting times, excess inventory, unnecessary motion, defects, and overprocessing. By identifying these areas of waste, the team can develop a plan to eliminate them or redesign the flow of materials and information to improve the overall process.

Steps to create a Value Stream Map

The process of creating a Value Stream Map involves several steps. By following these steps, teams can identify areas of waste and develop a plan to eliminate them. The steps are:

Identify the product or service to map, this can be the whole process of a company’s operations to deliver products/services or a sub process that requires attention.
Create a current state map that represents the current state of the process (As is)

- Include all the steps involved in the process including information and material flows.
- Include the time required for each step. Average cycle times can be used as well as the longest time for each step to target problem areas.

Analyze the process and identify areas of waste. This step is best done together with the different staff and stakeholders involved in each step. Also refer to the seven different types of waste.
Create a future state map that represents the ideal process. This should be similar to a perfect world scenario which is very efficient and delivers products and services promptly and without waste.

- Remember to eliminate all areas of waste.
- Target to reduce lead times to zero where possible.

Once the future state map is created, the team can develop an implementation plan to achieve the ideal process. This plan should include timelines, responsibilities, and metrics to track progress.

This is a key part of improving the process and business, by continuously monitoring and improving the process, teams can achieve sustainable results.

Components of a Value Stream Map

A Value Stream Map typically includes the following components. See the figure below for more details.

Customer: The customer represents the end user of the product or service. It is important to understand the needs and expectations of the customer in order to design an efficient value stream.

Supplier: The supplier represents an external party that supplies material or resources required to produce the product or service.

Process Boxes: The process steps represent the individual steps involved in the production process. These steps can include design, production, assembly, and shipping.

Process Data Boxes: Contain information related to the process, such as:
- Cycle Time (C/T) — the time it takes an operator to go through all of her work elements or steps before repeating them, usually for one stage of the production process.
- Lead time (L/T) — the time it takes one piece to move all the way through a process or a value stream from start to finish.
- Uptime — the percent of time a machine is ready and available for production
- Changeover time (C/O) — the amount of time required to set up a machine to make a different product or part number.
- % Complete and accurate (%C/A) — the percentage of product completed with perfect quality in a process step.
- Availability — the amount of time a process operates over a single shift. This is often measured in seconds. This includes all production times and downtimes.

Timeline & Summary Statistic: Most of times represented as the Lead Time Ladder

As shown in the figure below, the Lead Time Ladder can potentially be one of the most important aspects of a Value Stream Map, as it breaks down the cycle time by Value-Adding (VA) Activities, and Non-Value-Adding (NVA) Activities. It is important to note these times to help determine how to improve a process and where the delays and waste in the process are present.

By including these components in a Value Stream Map, teams can identify areas of waste and develop a plan to eliminate them. This can lead to increased efficiency, reduced lead time, and improved customer satisfaction.

Value Stream Mapping Symbols

There are many symbols that can be used to create a Value Stream Map. The figure below shows some of the most common symbols used. It can potentially take some time to familiarize with the different symbols, but it will be intuitive soon enough. The usage of these different symbols help add a lot of granular information into a process that cannot be easily explained using text alone.

Arrow Symbols

Arrow Symbols are usually used to show flow of information, materials, or work in process. The movement can either be “pushed” through the process or “pulled” through.

Manual Information Flow arrow is used when the information is given from one person to the next, it can also be through a walkie talkie within a short distance.

Electronic Information Flow arrow is used when information is transmitted through electronic means such as via a production management software on a computer, MRP system, tablet or even a phone. The information flow is usually over a longer distance than manual information flow.

Material Push arrow is used when materials such as inventory, work in process or finished goods are pushed from one step to the following process step or inventory warehouse.

Material Pull arrow is used when materials such as inventory, work in process or finished goods are pulled from a previous step to the following process step or inventory warehouse.

First In First Out arrow I used to signify a FIFO inventory warehouse which is controlled to operate in this manner or should be operating in this way. Material that leaves must have arrived prior to any other material currently in the store.

Stakeholder and Process Symbols

Stakeholder and Process Symbols are used to represent the different entities which exchange orders, information, and materials to deliver a good or service. They can also provide some basic identifying names or data to help simplify the process.

Customer is usually represented with a rectangular box, labelled as customer. In some cases like a b2b business a factory icon can represent the customer as well.

Supplier or Factory is usually represented with a factory style icon that is easily identified as a factory. Any manufacturing plant can be represented with this symbol.

Warehouse is represented with a rectangular box with a slanted roof on both sides. It may or ay not be labelled. This symbol is used for a finished good or inventory warehouse and not for work in process.

Process Step is the most basic but most common symbols in a value stream map. Each process step is represented with a rectangular box which may contain the process operator symbol if it’s a step requiring manpower.

Process Operator is represented with a solid filled circle and half circle representing arms of a process worker. This symbol is used when a process step requires manpower or human intervention.

Process Data Box are a vital part of the value stream map as they contain various data on each process. The information may differ between a product or service delivery process.

Material Flow and Process Symbols

Material Flow symbols are used to represent material flow, storage or process resources which are usually in and around the actual process steps. The ones represented below are the most common.

Work Cell is a group of workstations ( workers and machines) that are organized in a way that ensures smooth workflow, minimizes unnecessary movement and focused on making one specific product or sub-process function such as assembly of a component, painting or decoration.

Supermarket is a raw material inventory storage where a predefined amount of inventory is kept supplying a production process. It is a key concept in lean manufacturing and Just-In-Time (JIT) production systems, designed to manage inventory efficiently, reduce waste, and ensure a smooth flow of materials.

Safety stock is buffer stock to ensure production process steps can run smoothly without being idle due to delays in material flow due to production or quality issues.

Safety stock buys time for the factory to rectify any machine breakdown, process or quality issue while the downstream process continues operating.

Data base / MRP represents the need or presence of an MRP system to better manage the supply chain for the production process. It can also be used to represent storage of data.

Sequenced pull involves pulling materials through the production system in a specific sequence or order that matches the production order. Unlike traditional pull systems where materials are replenished based on consumption rates, a sequenced pull focuses on delivering materials in the precise order needed for production.

Inventory / WIP is used to represent raw materials, semi processed materials and parts that are moving through the production process. They can be present at the beginning, end or in between process steps.

Observation / inspection point is used when process workers need to manually inspect materials, components or parts being manufactured to ensure it meets the specification and quality requirements for it to be released to the next step in the process.

Cloud data storage represents the storage of data in a cloud storage system which is usually handled by an off-site data center or third party.

Lean Tools Symbols

Lean tools symbols are used to represent lean manufacturing tools and improvement methods that should be used to address problems within the value stream being analyzed for improvements.

Brainstorming is used to represent when a brainstorming session with the team should be held to identify potential solutions for an issue in the process or a more efficient way to design the process.

Kaizen is a Japanese term used for continuous improvement and this symbol is used to represent making small, incremental changes consistently to improve processes and eliminate waste.

Load levelling is a Japanese term also known as Heijunka, it is a lean manufacturing technique used to smooth out production schedules and workload across a manufacturing process. It aims to eliminate bottlenecks, reduce waste, and improve efficiency by balancing the production load evenly over a given time period.

Signal Kanban is used to represent a signal system to trigger a production of a specified quantity of an item when inventory reaches a certain level.

Production Kanban card instruct a workstation to produce a specified quantity of a product or component.

Withdrawal Kanban card are used to signal the movement of materials from one location to another, such as from a storage area to a production line.

Kanban post is a designated area where Kanban cards are collected and managed. It serves as a central point for organizing and processing Kanban cards, ensuring that production, replenishment, and withdrawal actions are triggered promptly and accurately.

Transportation Method Symbols

These symbols are used to represent transportation methods of materials and inventory along the value stream.

Airplane symbol is used when air cargo is required to move materials and inventory. This may be necessary due to time constraints are present or high value items.

Railroad symbol is used to represent rail freight movement of goods and materials. This may be more efficient than road or air cargo in some countries and production processes.

Truck/Road symbol is used to represent the most common form or transport for larger distances in manufacturing which is via road by truck or trailer. In some cases certain cars are used and these can be represented with the same symbol.

In summary

Value stream mapping is a powerful tool that can help organizations to improve their processes and increase their efficiency. By identifying areas of waste and developing a plan to eliminate them, organizations can reduce costs, increase throughput, and improve customer satisfaction.

It is an essential tool for any organization that wants to improve any productive processes, be it a manufacturing process or a service delivery process. By creating a visual representation of the entire value stream, teams can identify areas of waste and develop a plan to eliminate them. This can lead to increased efficiency, reduced lead time, lower cost, lower working capital requirements and improved customer satisfaction.

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