Chart a New Course to Efficiency with Value Stream Mapping

Lean manufacturing can help put many medical device companies on the path to increased profits and improved efficiency. The concept is simple—eliminate waste and enhance productivity. One of the most influential texts in the lean movement, Juran’s Quality Handbook, puts it succinctly: “A process is effective if output meets the customer’s needs. It is efficient when it is effective at the least cost.”¹

Most medical device makers have very effective operations and are good at keeping their customers supplied. But how many OEMs are truly efficient? Now more than ever, it is imperative to eliminate waste and streamline operations. In an increasingly competitive global industry, leading manufacturers must show that they can deliver on cost and speed in addition to quality. 

Many companies have become accustomed to enrolling employees in training courses that teach them lean concepts such as statistical process control or sophisticated design of experiments (DOE) techniques. These can certainly be valuable pursuits, but in a time of restrained budgets, the focus has rightly turned to actions that provide a quicker return on investment. One of the most cost-effective techniques that many medical manufacturers would benefit from exploring is value stream mapping (VSM). One of the benefits of implementing VSM is that it doesn’t require a team of Six Sigma black belts; even small- and mid-sized device makers typically have the resources to employ it successfully.

VSM, which, as is commonly known, was invented and developed by Toyota, involves breaking down every step of a process to separate the value-added steps from the nonvalue-added steps. VSM can be applied to any type of activity, including manufacturing operations, paperwork flow, and even sales or purchasing. It is one of the most basic lean concepts and among the easiest to learn and implement. Prospective practitioners do not need to study VSM intensely or attend a week-long seminar to master it. All that is required is a thorough understanding of the process and a willingness to consider unorthodox ways to attack old problems.

Many references are available on the Internet and elsewhere that can aid a user in mapping techniques and methods. Manufacturers should use whichever approach best works for them. The key is to ensure the entire process is mapped, from the initial step, such as a customer phone call, to the final step, such as the shipping of a finished product or the completion of a paperwork trail.

The first order of business when beginning a VSM project is to assemble the right team. It is preferable to have small teams of four to six people, though many companies form groups of 10 or more. The team should include a process expert who can accurately document each step of the operations. An engineer or someone with detailed product and process knowledge and an understanding of the customer’s requirements should also take part.

It is crucial to involve someone who can review the process with a fresh set of eyes. If the company has multiple geographical locations, it can be very beneficial to have an employee from another plant or even another country fill this role. Employees who see the same process running every day often become blind to any problems or issues; they tend to assume that the process is already optimal. After all, if they perceived it as flawed in some way, they probably would have taken action to improve it already.

When forming the team, take absolute care not to compromise the end product or negatively impact its fit, finish, or integrity. The purpose of a VSM exercise is to eliminate waste and make a company more effective, not to alienate customers or spark a rash of complaints. Do not, for example, substitute a cheaper material for a component without customer authorization. In general, it is a good idea to avoid changing the physical or chemical properties of a component or device. Any product-related modifications, such as changes in suppliers or to the process, should be carefully coordinated through customer engineering.

Once the team is formed, begin carefully mapping out the process. A popular method is to plot the steps using diagramming software, such as Microsoft’s Visio, and then project the diagram on a screen. However, if such software isn’t available, a white poster board will do. There’s no one best way to document a process—the main concern is to make the diagram visible so that the entire group can view it simultaneously. This will give everyone the opportunity to contribute to the development of the diagram, increasing the likelihood that it will capture every detail of the process and encouraging team members to think creatively about ways to make the process better. 

List value-added activities on one line and keep non-value-added activities on a separate line. Once the basic process flow is developed, go back through and indicate process time for each step. Don’t forget to document the steps between the value-added stations. Typically, these are what take up most of the time in a manufacturing cycle. Also study how the operators perform their work. Is every motion required? Can some be combined or eliminated?

When developing its approach, Toyota identified seven areas of waste.² As you analyze your workflow, look for each of these areas of waste, which can be defined as follows:

Remember, the primary goal is to eliminate waste, which Fujio Cho of Toyota defines as “anything other than the minimum.”³ Several studies have shown that up to 95% of a product’s flow can be made up of nonvalue-added activities. This means that in some cases, up to 95% of production is devoted to holding materials in storage, where they wait to be transferred, processed, or inspected.³ The group should focus only on the activities that truly enhance the final product.

A secondary goal should be developing a sense of flow. When drawing or witnessing the process, does it seem intuitive? Does it feel like an optimal solution? Do visitors to the plant immediately get a sense of order? If not, this is an area to focus on.

Remember that there is always room for improvement. After this VSM event is completed, it should be followed by another, which in turn should be followed by another, and so on. Each event should dig progressively deeper into the process. The team should walk the manufacturing floor with the process map and confirm that each step has been accurately recorded.

When the team is done, it should end up with something similar to the example shown in Figure 1. Note that the entire process is represented clearly on one 8.5 × 11-in. sheet of paper. The diagram can be intimidating, but experience with the process will increase understanding and ease any trepidation.

Each step, from order-taking to completion, is shown. The line along the bottom shows the time consumed by each movement. In this example, the steps that add value to the final product took a total of 86 minutes to complete. This stands in stark contrast to the total time it took to process the part through the plant, which the group marked at 37 days. The balloons represent ideas the team generated during its brainstorming efforts. The takt time, or the cycle time needed to meet the customer’s demand, is listed at the top.

When you start to make your own diagram, begin with product flow. List the key process milestones. There is no need to be perfect the first time through; a simple flow diagram will do. Walk through the process from the beginning to the end, and then walk back through it to the beginning. Focus on flow. After the entire process has been documented, begin to add in detail. What is the cycle time of each process step? What is the typical wait time between each process step?

Next, edit and organize the process flow. The format of the final diagram can be similar to that depicted in Figure 1, or you can follow one that feels more comfortable.

The next step is key to the success of the VSM event: It’s time to start brainstorming. Go over every step of the process. Identify what can be done better or where waste can be eliminated. Every idea should be documented and reviewed. The basic rules of brainstorming are as follows:

At this point, the team does not know exactly how to improve the process, so it’s important to generate a large quantity of ideas. Be sure to give every idea equal weight at first, and be sure to give positive reinforcement to each team member who presents an idea.

Lastly, the team needs to put together all of its ideas and knowledge and establish a future state map, which represents the team’s vision for an optimized product flow. This will function as a wish list of every possible process improvement. Engineers or managers will then refer to the VSM when determining which suggestions are economically justifiable.

One of the great things about VSM is that there are few constraints in terms of when the method can be utilized. It can be used to optimize the most complex manufacturing process, or it can be used to simply track the flow of paperwork through a given system.

Conclusion

Just stopping to think about process flow and actually documenting it can help identify and eliminate hidden waste. Always remember that if you “simplify, goods will flow like water.”⁴ VSM can also serve as a reality check, revealing whether the repetition of filling orders day after day has allowed inefficient habits to drift into the process. While it uses relatively few resources, VSM can help trim costs and boost turnaround times, something that every manufacturer would love to accomplish. 

Everyone is busy. Many of us are doing jobs that used to be performed by two or even three people. Eliminating waste can boost quality and decrease costs. Manufacturers who are strapped for resources can embrace VSM as a quick, inexpensive, and effective tool for improving their business.

References

1. Joseph M Juran, Juran’s Quality Handbook, 5th ed. (McGraw Hill, 1999).

2. Kiyoshi Suzaki, The New Manufacturing Challenge: Techniques for Continuous Improvement (The Free Press, 1987).

3. Yasuhiro Monden, Toyota Production System: An Integrated Approach to Just-in-Time, 2nd ed. (Industrial Engineering and Management Press, 1983).

4. Richard J Schonberger, Japanese Manufacturing Techniques: Nine Hidden Lessons in Simplicity (Simon and Schuster, 1982).