Abstract:

In this project we study several cases that show us how lean management and six sigma are used in ergonomics and how they are undoubtedly complement each other. These cases study have found that six sigma methodology particularly useful in identifying and validating root causes that are hard to discern because of their subjectivity, and in focusing improvements to an ergonomics program in way that caused measurable improvements.

This project shows that an appropriate implementation of Six Sigma and Lean in ergonomics can create a clear path for solutions that will have a positive impact on the cost , quality and safety. Such methods help to identify opportunities for improvement, highlight non-value-added steps, and organize the workplace for peak efficiency. Combined with change management and leadership systems, they can empower people to work together, to apply common methods and to develop sustainable solutions based on solid evidence rather than intuition or organizational politics.

Introduction:

1. Lean thinking:

The concept called "lean management" or "lean thinking" is most commonly associated with Japanese manufacturing, particularly the Toyota production system (TPS) much of the TPS way of thinking is based on that managers should stop depending on mass inspection to achieve quality and, instead, focus on improving the production process and building quality into the product in the first place.

Lean thinking is not a manufacturing tactic or a cost-reduction program, but a management strategy that is applicable to all organizations because it has to do with improving processes. All organizations are composed of series of processes, or sets of action intended to create value for those who use or depend on them (customers)

The core idea of lean involves determining the value of any given process by distinguishing the value-added steps from non-value-added steps, and eliminating waste so that ultimately every step adds value to the process.

To maximize value and eliminate waste, leaders in the organizations, must evaluate processes by accurately specifying the value desired by the user; identifying every step in the process (or "value stream ," in the language of lean) and eliminating non-value-added steps; and making value flow from beginning to end based on the pull-the expressed needs- of the customer..

A perfect process creates precisely the right value for the customer. In a perfect process, every step is valuable (create value for the customer), capable (produce a good result every time), available (produces the desired output, not just the desired quality, every time), adequate (does not cause delay), flexible, and linked by continuous flow. Failure in any of those dimensions produces some type of waste. The Toyota production system (TPS) identifies seven categories of waste: overproduction, waiting, transporting, processing, inventory, motion, and correction.

2. six sigma:

Six Sigma (6) is a business-driven, multi-faceted approach to process improvement, reduced costs, and increased profits. With a fundamental principle to improve customer satisfaction by reducing defects, its ultimate performance target is virtually defect-free processes and products. The Six Sigma methodology, consisting of the steps "Define - Measure - Analyze - Improve - Control," is the roadmap to achieving this goal. Within this improvement framework, it is the responsibility of the improvement team to identify the process, the definition of defect, and the corresponding measurements.

Six Sigma originated at Motorola in the early 1980s in response to a CEO-driven challenge to achieve tenfold reduction in product-failure levels in five years. Meeting this challenge required swift and accurate root-cause analysis and correction. In the mid-1990s, Motorola divulged the details of their quality improvement framework, which has since been adopted by several large manufacturing companies.

As the roadmap for actualizing the statistical thinking paradigm, the key steps in the Six Sigma improvement framework are Define - Measure - Analyze - Improve - Control . Six Sigma distinguishes itself from other quality improvement programs immediately in the "Define" step. When a specific Six Sigma project is launched, the customer satisfaction goals have likely been established and decomposed into sub goals such as cycle time reduction, cost reduction, or defect reduction. The Define stage for the specific project calls for base lining and benchmarking the process to be improved, decomposing the process into manageable sub-processes, further specifying goals/sub-goals and establishing infrastructure to accomplish the goals. It also includes an assessment of the cultural/organizational change that might be needed for success.

Once an effort or project is defined, the team methodically proceeds through Measurement, Analysis, Improvement, and Control steps. A Six Sigma improvement team is responsible for identifying relevant metrics based on engineering principles and models. With data/information in hand, the team then proceeds to evaluate the data/information for trends, patterns, causal relationships and "root cause," etc. If needed, special experiments and modeling may be done to confirm hypothesized relationships or to understand the extent of leverage of factors; but many improvement projects may be accomplished with the most basic statistical and non-statistical tools. It is often necessary to iterate through the Measure-Analyze-Improve steps. When the target level of performance is achieved, control measures are then established to sustain performance. .

3. Ergonomics in lean and six sigma;

lean principle set to eliminate waste in cost and time but by ignoring the ergonomic side more waste will occur and this waste occur as example in the treatment of the injury or illness in workers and lean set also to reduce the motion distance and it is not ergonomic for workers at the same time.

Factors that complement ergonomic with lean principle:

1-  Lean prioritization: this factor can be summarized by selecting work areas or processes for lean analysis and this can be done using many tools mainly value stream mapping to determine the needed processes.

2-  Ergonomics training: it is a critical factor in any lean process and it includes training lean team leaders and members. Training program must include ergonomic concepts and ergonomic design factors in order to apply them in the suggested improvement.

3-  Ergonomic Design: Focusing on ergonomic design factor concepts will help them accomplish their lean goals while considering how employees interface with workstations, tooling, parts and environmental factors. By applying these concepts cost due to errors will be reduced in addition to improve productivity and reduction in CTD risk factors which lead always to high workers' compensation costs.

4-  CTD risk assessment: It is an important factor in it quantifying the CTD risk factors must be presented before and after the new lean workflow and workstation design implantation and this factor will lead us to clear view of the positive impact on the level of CTD risks.

5-  Stakeholder involvement: These stakeholders understand problems with workflow, issues with incoming parts and equipment, and variances in production scheduling that may not apparent to an external lean team. It is also crucial to the acceptance and effective implementation of the lean design modification.(some involvements / Hourly employee, supervisors, maintenance, …).

6-  Quantifying the impact: It is important to measure the financial impact of lean ergonomics solutions which is related to this factor

7-  Creating a culture of success: Establishing a culture of employee involvement and empowerment in the lean ergonomics process helps produce a positive working environment in which workplace changes are expected and accepted. Sharing the mission will help to make process successful and effective.

Ergonomics and six sigma

Six sigma is set to eliminate variability and ergonomics applies the information about human capability to minimize this variability since sigma data driven process we can evaluate the risk scores on the human body.

Case studies:

Case #1: The Dow Chemical company

The Problem
Reducing Musculoskeletal Disorders:
Ergonomics-related injuries, including musculoskeletal disorders (MSDs) caused by repetitive strains, continue to be a serious problem for employers. In 2002, ergonomics-related injuries accounted for a third of all workplace injuries involving missed work time, with an average absence of nine days per injury.1 The resulting worker injury claims and loss of productivity are estimated to cost $13 to $20 million per year for U.S. employers.2 As computer workstation users spend more and more time at desktops, the risk of MSDs occurring has increased. Yet, as illustrated below, in many companies there are inherent difficulties and concerns associated with addressing this increased ergonomics risk.
For example, Tricia, the Environmental, Health and Safety (EH&S) Leader for the Specialty Chemicals Business of The Dow Chemical Company, wants to reduce MSDs among computer workstation users throughout her business’ various divisions and operations. Before she can understand what changes to make in either the workstations or the work practices in those divisions, she must identify the root causes of MSDs among the operators. Although she has some theories, Tricia does not know for sure what factors are causing or contributing to the employees’ MSD complaints. Only by knowing the root causes can she implement with confidence controls that would achieve positive results.
Tricia also suspects, but is not sure, that many of the root causes of MSDs are the same across the different operations and divisions in her business. Because of constraints on both her budget and time, Tricia would like to design one basic program that is flexible enough to implement company-wide. She also knows that any reductions achieved under the new program must be sustained over the long term, and she is concerned that over time employees and managers will "backslide" on their commitment to the program and return to their ergonomically risky behaviors.
Fortunately for Tricia, she could refer to a similar project successfully undertaken by the Design and Construction function of The Dow Chemical Company, which is discussed in the case study below. This project, which utilized a problem-solving methodology called "Six Sigma," offered an innovative way to address Tricia’s concerns for the development and implementation of a sustainable program to reduce MSDs throughout her business.

The Solution
The Dow Chemical Company’s Innovative Use of "Six Sigma":3
Avoiding ergonomics-related injuries is an important component of The Dow Chemical Company’s ("Dow" or "the Company") overall emphasis on safety and health. Dow is a science and technology company that develops, manufactures and provides various chemical, plastic and agricultural products and services for customers in over 180 countries. In 1994, Dow adopted a set of voluntary 10-year EH&S goals to dramatically improve the Company’s performance by 2005. These goals call for a reduction in the Company’s reportable injury and illness rate by 90 percent to 0.24.
In 2000, the company identified an opportunity to improve its injury rate within the Dow Design and Construction business unit. Dow Design and Construction ("DDC") is responsible for managing the design and construction of Dow’s facilities worldwide. Because DDC’s approximately 1,250 workers (including employees and contractors) work primarily at desktop workstations, where they spend the majority of their time working at computer keyboards, they were increasingly susceptible to ergonomics injuries. While the rate of ergonomics-related injuries among the DDC workers was low (only three were reported in 1999), the Company chose to make proactive improvements before ergonomic injuries increased in number or severity.
Dow’s EH&S function decided to address ergonomic injuries at DDC using the "Six Sigma" problem solving methodology. Six Sigma is a disciplined, process-oriented approach to problem solving, adopted by Dow and many other companies, which emphasizes the reduction of defects in processes, products and services by applying a four-step improvement methodology. Because Six Sigma emphasizes sustainable results over short-term fixes, Dow has found it particularly useful for EH&S projects. Following the steps prescribed under Six Sigma, Dow developed a Six Sigma project team, which first defined the primary contributing factors to MSDs in the DDC function, and then sought to reduce the those factors by 70 percent. While each of the four steps of the Six Sigma project are outlined below, a more detailed discussion of the Six Sigma methodology appears at the end of this case study.
Step 1: Measure
Once the Six Sigma project team developed its charter and defined its task, it then began by defining the current process. First, the team outlined the sequence of events from workstation assignment to task performance and potential injury. They next identified a series of key variables affecting the process outcome that included:

§  user attributes (such as daily time at workstations);

§  user behaviors (including posture, force, and duration of use); and

§  Environmental factors.

In this phase of the Six Sigma method, the "defect" – a measurable outcome of the process for which improvement is desired – is defined. While the true "defect" for this process would be the occurrence of an ergonomic injury, there were so few at the start of the project that measuring a statistically significant improvement was going to be difficult. Therefore, the key process variables identified were taken as the "defect," and a goal of 70% improvement (reduction) in the baseline level was set for the project. Scored surveys of DDC workstation users were developed and conducted on the variables identified and used to measure the baseline defect level.
Step 2: Analyze
Accurately identifying the root causes of a problem, which in turn leads to more effective improvements, is an essential function of the Six Sigma methodology. Therefore, the project team next analyzed the collected survey data to determine differences in the workstations, work environments, user training, and behavior at the different DDC sites. The team then identified possible root causes underlying these variables using several of the Six Sigma tools and methodologies, including brainstorming, ‘fishbone’ diagramming, a work performance matrix, and Antecedent-Behavior-Consequence and Balance of Consequences analyses. After developing a list of possible root causes, the team used additional Six Sigma tools and methodologies to identify probable root causes and validate them. For example, one possible root cause identified was a failure of the employee to recognize the importance of ergonomics compliance to his or her personal well-being. This root cause was validated by the employee survey, in which many of the employees expressed an attitude of "it won't happen to me."
Other key root causes validated through this process were the lack of adjustable furniture at some worksites and a lack of "ownership" in personal safety on the part of the employee. The team also determined that ergonomics was not emphasized by DDC to the same extent as other, more immediate, safety issues such as the use of personal protective equipment in hazardous environments.