Value stream mapping (VSM) is a core component of lean manufacturing. It helps companies identify waste, streamline processes and reduce costs.
Well-designed VSM frameworks set the stage for the development of continuous improvement solutions. Let’s discuss the fundamentals of value stream mapping, define key elements, identify common pitfalls and provide a step-by-step roadmap for your VSM journey.
What is value stream mapping?
Developed as part of the Toyota Production System, value stream mapping is the creation of a diagram that shows all the actions required for raw materials to be sourced, processed, assembled and finally shipped to customers.
VSM maps function as visual tools that let teams quickly identify process bottlenecks, redundancies and areas of underperformance. These maps highlight the impact of both value-adding and non-value-adding activities, in turn allowing companies to eliminate waste and improve productivity.
In practice, value stream mapping in the manufacturing industry starts with a current state map, which illustrates existing material and information flows throughout the organization. Subsequently, teams create a future state map to represent the ideal flow. By comparing these two maps, teams can identify areas for improvement and develop action plans that address key concerns.
The purpose and benefits of value stream mapping
Value stream mapping can help manufacturers reduce costs, increase throughput and enhance quality. In addition, maintenance value stream mapping can help reduce the risk of unexpected machine failure and production downtime.
Waste identification = reduced costs
First up is waste identification. Lean manufacturing value stream mapping identifies eight types of waste. There’s an easy acronym to help remember them all: TIMWOODS.
- T: Transportation waste is the unnecessary movement of products or materials. In a warehouse, this could be the movement of products multiple times to accommodate changing inventory schematics.
- I: Inventory waste occurs when companies have more materials or finished products on hand than they need. For example, holding excess raw materials “just in case” can tie up inventory space and lead to higher storage costs.
- M: Motion waste is similar to transportation waste but refers to people or equipment. Consider a specialized tool that is constantly being moved from one place to another. This not only increases lead time but also ramps up the risk of machine failure.
- W: Waiting constitutes idle time, which can arise from machine failures or bottlenecks that disrupt production workflows.
- O: Overproduction waste is the creation of more products or components than are currently needed.
- O: Overprocessing waste occurs when additional work is performed on products or services that does not add value but increases production time.
- D: Defects waste refers to errors or imperfections that require time to correct or that render products unsellable.
- S: Skills waste happens when companies don’t make best use of employee talents and training. For example, having a highly skilled employee running a basic process means their skills aren’t being used and therefore aren’t delivering maximum value.
Identifying and reducing waste in manufacturing in turn reduces unnecessary operational costs.
Holistic process views = improved throughput
Value stream mapping displays an entire process (or multiple processes) from start to finish. This provides a holistic view of current operations and allows teams to identify systemic issues.
Consider the VSM for a vehicle component. If one assembly process consistently takes 2x or 3x longer than all adjacent processes, it may indicate roadblocks or bottlenecks. Equipped with a complete value stream map, teams can target these processes directly. The result is improved throughput as systemic issues are identified and resolved.
Team alignment = enhanced quality
Fragmented processes can create issues with consistent quality. For example, if two teams both assume that the other team is handling a key aspect of quality control, the result may be increased product defects.
Effective value stream management fosters cross-functional collaboration between operators, engineers and managers around shared goals. This helps eliminate redundant processes and identify operational gaps to improve overall product quality.
Key elements of a value stream map
While every VSM is unique to its organization, there are five key elements that all lean manufacturing process mapping share: Process boxes, inventory and WIP icons, symbols and legends, material and information flow arrows, and timeline or lead time bars. Let’s explore each in more detail.
- Process boxes: Each major process step or workstation is depicted as a process box. This box contains information about the process including cycle time, uptime, scrap rates, failure rates and other relevant metrics.
- Inventory and WIP icons: Inventory and work-in-progress (WIP) icons indicate how many parts or subassemblies are required between process steps.
- Symbols and legends: VSM maps also contain symbols and legends to help easily identify information. While you can use whatever set of symbols works best for your business, most manufacturers choose standard lean icons for suppliers, customers, production controls and data boxes. This ensures that value stream maps are consistent across your organization.
- Material and information flow arrows: Material and information flow arrows indicate the direction of physical materials and digital information. Consider customer orders, for example: the process begins with placing an order, followed by an arrow that leads to the next step — ensuring inventory is available. The subsequent steps are order scheduling, inventory picking and finally, shipment. Flow arrows make it easy to track the process from start to finish.
- Timeline or lead time bars: Timeline bars represent the “heartbeat” of your system. They indicate the total lead time, which is the time required to complete a process or navigate the stream from start to finish, as well as the value-added time, which is time spent on processes that add value to the product.
Steps to create a value stream map
Preparation is the key to reliable outcomes and improved operational efficiency with value stream mapping. While it’s tempting to jump right in, follow these five steps to set the stage for success.
- Step 1: Select a single process or product family for your value stream map. This provides clarity of purpose and function — attempting to complete multiple maps simultaneously can create the same bottlenecks you’re looking to avoid. By focusing on a specific process, teams are better prepared to develop and implement rapid improvement events (RIEs) that address costly roadblocks or reworks.
- Step 2: Form a cross-functional team. Your VSM team should include operators, supervisors, engineers and a lean principles facilitator. Give the team a chance to meet and establish common goals before drafting your first diagram. This helps ensure that roles are clearly defined and reduces the risk of redundant efforts.
- Step 3: Walk the process with your team to see processes in action. Also called a Gemba walk, this means going out onto the production floor to observe cycle times, wait times, inventory counts, rework loops and other key processes.
- Step 4: Draft the current state map using real-world data. Ensure that each step is clearly plotted and supported by measured metrics. Incorporate a process for double-checking to verify that all data is up-to-date and accurate.
- Step 5: Conduct a future state brainstorm. With the current state map in place, teams can brainstorm future state goals. This process includes identifying areas of waste, creating action plans to address these areas and defining the lean manufacturing tools needed to reduce total waste.
It’s also worth considering the roles and responsibilities required for VSM data capture and value stream analysis. For example, at least one team member should be assigned to gather internal process data about cycle, wait and rework times. This data should then be reviewed by one or more other team members and verified against company databases.
In addition, every VSM team should have an executive sponsor who supports the process with time and resources. This C-suite member also takes accountability for the project at scale, allowing teams to focus on the task of improving operations.
Common pitfalls and best practices
While value stream mapping opens the door to reduced waste and improved manufacturing process performance, this approach also comes with its potential pitfalls.
- First is overcomplication. The goal of VSM is to identify process backlogs and streamline operations — if maps are stuffed with information and difficult to read, they become part of the problem.
- Next is the lack of operator involvement. While maps are often designed by managers and team leads, these diagrams won’t deliver improvement without buy-in from frontline staff. Best bet? Loop in department heads and production floor workers as early as possible in the project.
- Last but not least is relying on static maps. Manufacturing value stream maps must evolve along with production line advances, staff changes and output targets. Once VSM begins to pay dividends for a company, however, it’s tempting to simply stay the course. The result is infrequent re-mapping which can lead to VSMs that no longer reflect current operations. Regular re-mapping keeps value stream maps on target.
To maintain momentum after initial gains, businesses should create an action plan or build a Kaizen backlog to ensure identified issues are resolved quickly.
Getting started with VSM
Value stream mapping is a core component of lean manufacturing process frameworks. Equipped with end-to-end process visibility, businesses are better prepared to identify bottlenecks, reduce waste, streamline operations and improve ROI.
To make the most of VSM, start with a pilot project on a single product line. Explore the impact of mapping within this line and across its processes; once you have a firm grasp on the basics, scale the process across more lines.
Ready to streamline operations with value stream mapping? ATS can help. From facilitating VSM workshops to analyzing data, implementing changes that align with lean value stream mapping objectives and delivering outsourced maintenance services, ATS enables your team make the most of VSM.
