Most people in industry today recognize that lean manufacturing helps manufacturers and plants improve efficiency by eliminating waste in the production process.
But what exactly is lean manufacturing, and how is it implemented?
The first reality to keep in mind with lean is that it isn’t one particular process. It’s an adaptable set of tools that can be applied to any system of manufacturing—whether that system produces valves, flowerpots or magazines. No matter which tools are used, however, manufacturers implementing lean into their processes will start by identifying waste in the process (known in lean parlance as muda). The focus then becomes elimination of muda bit by bit until production is as streamlined and efficient as possible.
BACKGROUND AND HISTORY
Lean manufacturing has roots in Henry Ford’s assembly line, but Japanese entrepreneurial scientists—predominantly those working at Toyota Motors—are credited with developing many of the lean tools in use today (Figure 1). While the term, “lean manufacturing,” wasn’t coined until 1988, Toyota started developing methodologies for eliminating waste as early as the 1930s.
Ford’s Assembly Line
Henry Ford’s manufacturing process was revolutionary for its time. By implementing what he called “flow production,” characterized most visually by the assembly line, Ford’s automotive fabrication plant could churn out car after car with a high degree of quality and precision. But flow production had its flaws, namely the lack of adaptability.
If Model Ts were the only car Ford ever made, the company could have stopped right there. However, the problem of variety in product soon showed up. While flow production all but eliminated human error and manufacturing defects, it was nearly impossible to use the same processes to manufacture anything but that beautiful, black Model T.
With Ford’s system as a starting point, engineers at Toyota Motors (then a division of Toyoda Automatic Loom Works) began perfecting the flow production concept. The system that the company developed, called the Toyota Production System (TPS), formed the basis for modern lean manufacturing.
Since TPS emerged, lean has become as academic as it is practical with hundreds of papers and books written about it. In fact, the term, “lean manufacturing,” was coined in an MIT master’s thesis.
A wide variety of approaches to lean now revolve around different sets of tools, and these tools are constantly in flux. You could say, then, that lean manufacturing is the intersection of theoretical and applied science in manufacturing.
While quite a lot has changed over the decades—both in manufacturing technology and the products themselves—the basic goals of lean manufacturing remain the same:
- Eliminate waste
- Increase throughput speed
- Improve quality of products
FIVE LEAN TOOLS TO KNOW
For any company interested in going lean, the most important thing is to learn what tools and ways of thinking are available to help. While dozens of lean tools and methods have been identified, the following five concepts provide a solid basis for understanding the lean manufacturing mindset. None of these tools is all-inclusive as the way to go lean, but rather they provide a different way of thinking that can be put into an individual company’s processes and methods.
5S is often the launching point for businesses just starting out to implement lean manufacturing. Much of 5S seems to be common sense, but implementing these steps can result in significant improvements in efficiency and quality. Just having the structure of working on these areas can give a plant the right direction. The five steps (Figure 2) are:
- Sort: Every workspace is organized by separating the necessary (materials, tools) from the unnecessary (waste, scrap, redundancies) and removing anything unnecessary from the production area.
- Set in order: The necessary inputs of production (equipment and materials) are laid out in an easy, intuitive manner.
- Shine: The workspace is cleaned, and clutter is removed.
- Standardize: A list of instructions for repeating the first three steps is made, so that any employee who arrives in the workspace knows exactly how to proceed.
- Sustain: This is what’s called the “rinse and repeat” phase. In other words, it is ensuring that sort, set in order and shine occur on a regular and ongoing basis, so that the workspace stays clean and clutter-free at all times.
Gemba translates roughly to “the real place,” referring to the physical space where the company creates value. For manufacturers, Gemba encourages executives and upper-level managers to spend as much time as possible on the shop floor, interacting with employees and witnessing the production process firsthand.
By adopting a culture of Gemba, companies can improve in several ways, including:
- Building communication chains between the shop floor and the executive offices, often by performing “Gemba Walks,” or managerial and executive visits to production facilities
- Promoting a more thorough understanding of issues that affect production, such as worker skills, equipment performance and materials handling.
One of the cornerstones of lean manufacturing is Kaizen, which focuses on continuous improvement in the manufacturing process. While Gemba promotes a more thorough understanding of the production process, Kaizen continues by helping the company orient itself toward ongoing, incremental improvement. To implement Kaizen, a company must:
- Promote communication between shop-floor employees and management, often by adopting Gemba practices
- Regularly request feedback from employees on day-to-day processes, equipment status and workplace atmosphere
- Separate, record and quantify all aspects of production to more easily identify patterns and improve accountability
- Continually stay abreast of technological advancements that may improve or facilitate production
Takt time is the average time allowed for manufacturing a product to match customer demand. Takt time can be calculated with a simple formula:
takt time = time available (per period)/customer demand (per period)
The resulting value gives manufacturers an idea of how often they should schedule the start of production for each part.
Implementation of takt time motivates manufacturers to eliminate waste in the production system by zeroing in on bottlenecks and to remove non-value-adding work from the process.
Total Productive Maintenance
Total productive maintenance (TPM) is an equipment-focused tool that aims to eliminate four factors: breakdowns, slow operation, defects and accidents. Training and scheduling are two important aspects of TPM, which focuses equally on equipment operators and on management.
The following are the “pillars” of TPM:
- Autonomous maintenance: Operators are made responsible for cleaning and maintaining equipment.
- Planned maintenance: Maintenance tasks are scheduled based on likely periods between failures.
- Quality maintenance: Error detection is added to the production workflow, and root-cause analysis is used to solve any problems.
- Focused improvement: Collaboration to regularly achieve small process improvements is encouraged.
- Early equipment management: Knowledge of failures and issues to improve installation or production of new equipment is applied.
- Training and education: This is ensuring everyone, from headquarters to the shop floor, is equipped with the knowledge to implement TPM principles.
- Safe and healthy environment: Hazards and risks to all employees are minimized wherever possible.
- TPM in administration: The seven guidelines listed above should be applied not just to plant employees but to company administration.
ACHIEVING LEAN SUCCESS
Just as no two companies are alike, no two lean journeys follow the same path. Every lean tool must be adapted to the particular type of production that is occurring, to the size of the company and to the facility’s space and challenges. There are, however, a few common practices that can increase a company’s chances of achieving lean success.
Start with 5S
5S is often the first lean tool implemented because it’s easy to adapt to just about any environment. Companies may then go on to incorporate other aspects of lean, such as putting Gemba in place and moving onto Kaizen practices.
To start using 5S, companies don’t need to make drastic changes to workflows, scheduling systems or overall company culture. Instead, they can simply fashion their operations using the 5S acronym of sort, set in order, shine, standardize, sustain. Implementing 5S can lead to cleaner, less-cluttered workspaces. Less clutter and more order means employees will always know where to find tools, and waste materials will stop occupying useful space on the plant floor. Furthermore, 5S can create a more welcoming environment for clients touring the manufacturing facility, which can lead to higher sales conversion rates.
Hire Outside Help
Some companies implement 5S, then claim they are now practicing lean manufacturing. This isn’t entirely inaccurate, but there’s a night-and-day difference between dabbling in 5S and reinventing production systems from a lean standpoint or redoing the company thinking by producing takt time processes.
That’s why many companies start their journey with an external consultant. Professionals trained in lean manufacturing tools and techniques know the best way to thoroughly evaluate a company to identify what and where waste is. This is often over a period of weeks or months. These lean specialists then can offer concrete, strategic recommendations to move forward geared precisely to those places where waste exists.
Having a third party onsite during implementation of lean helps in two ways. First, it allows manufacturers to draw on decades of lean experience and theory without taking time off for specialized training in the ways of lean. Second, third-party consultants often provide ideas that would be overlooked by core, long-term staff who may have been doing things a certain way many years. When a company has used the same methods for a long time it’s sometimes hard to see change as a viable option.
The cost of hiring lean consultants might seem high, but an effective lean strategy allows companies to recoup those costs in a short amount of time.
PREPARE TO MAKE CHANGES
Despite producing very real gains in both the short and long term, lean manufacturing is not without its challenges. In addition to consulting fees, companies that go lean often invest huge amounts in new equipment and building updates such as newer electrical connections, improved ventilation and transportation rerouting.
Lean manufacturing also is sometimes criticized as responsible for stifling individuality on the shop floor. Operators sometimes have their own preferred methods of getting things done.
To successfully implement lean requires a different way of thinking. Everyone has to agree on an optimal way of doing a job, and everyone has to do the job exactly that way or the system will fail. While the changeover can be difficult for some, any negative effects on morale can be offset by opening clear channels of communicating the whys and hows of what’s being done as well as by promoting accountability at all levels.
One of the ways lean manufacturing differs from other efficiency strategies is that implementation is not top-down. Lean manufacturing is a company-wide commitment that needs to be shared by employees at all levels, from the shop floor to the executive offices. If everyone is dedicated to improvement, informed of changes and involved in lean discussions, the company has a good chance of success.
Even without calling what’s done “lean manufacturing,” successful companies around the world already embrace waste elimination, product quality and efficiency. The tools of lean simply offer a way to quantify, measure and implement these improvements. Despite some challenges, lean manufacturing can be a rewarding process and a solid investment, leading not just to increased profits but also to improved workforce morale and overall company perception.
What’s more, both customers and suppliers tend to see lean companies as more reliable, more stable and generally better business partners.