Respuesta hidrológica - modelación hidrológica

A primary goal of Six Sigma is to reduce the variation of processes and prod- ucts from the end customer’s perspective. For example, with the US Postal Service, if you mail a letter from New York to Los Angeles, you should expect it to arrive in four business days (this is the average or mean delivery time). The letter will not always be delivered in four business days, there will be a range or variation in the actual delivery time, such as the letter being deliv- ered in as few as two days or as many as six days (the range or standard

44 Lean Six Sigma for Engineers and Managers: With Applied Case Studies

deviation of the delivery time). One of the primary goals of Six Sigma is to reduce this variation to zero; in other words, the letter will be delivered in four business days every time. This will allow customers to better plan their business processes and their expectations of the US Postal Service. Relating this to a Sigma level, a Sigma quality level measures the variation or spread of a given process in terms of the standard deviation of the process and how well it meets customer expectations. The higher the Sigma level is, the better. So in the case of the US Postal Service, assume that the mean delivery time is four days (μ = 4) and the standard deviation is plus or minus two days (σ = 2).

Assume that the customer needs the letter to be delivered within two to six days. We can calculate the US Postal Service’s Sigma level, by dividing half the customer’s requirement (delivered within two to six days) by the standard deviation of the process (two days). In this example, the US Postal Service is operating at a One Sigma level. If the Postal Service were able to reduce the standard deviation of their process from two days to one day (σ = 1), the US Postal Service would now be operating at the Two Sigma level. If the Postal Service could reduce variation even more, they could operate at a higher Sigma level.

Prior to the introduction and proliferation of Six Sigma in the 1990s, three Sigma quality levels were the acceptable benchmark for quality. In other words, a company could operate at the three- Sigma level and be considered a quality leader in the field. Now, a Six Sigma level is the quality expectation and “stretch” goal for many organizations. From a statistical perspective, a Six Sigma operating level corresponds to the number of defects generated, often times referred to as defects per million opportunities. If a company is operating at a Six Sigma level, the company will produce 3.4 defects per mil- lion parts produced by the company. In contrast to the Six Sigma operating level, the Three Sigma quality level translates into 2,700 defects per million parts produced. Considering the complexity of modern processes, Six Sigma quality isn’t optional; it’s required if the organization is to remain viable [1]. The requirement of extremely high quality is not limited to multiple- stage manufacturing processes; consider what Three Sigma quality would mean if applied to other processes [1]:

• Virtually no modern computer would function.

• 10,800,000 healthcare claims would be mishandled each year. • 18,900 US savings bonds would be lost every month.

• 54,000 checks would be lost each night by a single large bank. • 4,050 invoices would be sent out incorrectly each month by a modest-

sized telecommunications company.

• 540,000 erroneous call details would be recorded each day from a regional telecommunications company.

• 270,000,000 (270 million) erroneous credit card transactions would be recorded each year in the United States.

45 Metrics and Performance Measurement

To help maintain Six Sigma levels of quality several parameters are worthy of tracking to gauge an organization’s effectiveness:

• Key process output variables • Key process input variables • Estimated completion date • Actual completion date • Tools utilized for the project • Open action items

• Baseline measurements • Financial calculations

• Actual project environment benefits and financial savings • Lessons learned concerning project effectiveness

From this information, managers can gain insights into the effectiveness of each project and the overall success. Successful projects can also be achieved for use in later projects. In general, metrics need to capture the right activity and be designed to give immediate feedback. Successful metrics focus on the process rather than the product or individuals.

Reference

47

6

Deployment Alternatives

6.1 Introduction

The economic and quality benefits of Lean Six Sigma are clear. Many orga- nizations can significantly improve their bottom- line performance and improve customer satisfaction by focusing efforts using the Lean Six Sigma methodology. This chapter covers the next phase of that process, after the need has been identified that cost and quality improvement are important organization goals. The next phase is implementation and execution. There is a variety of alternatives to deploy Lean Six Sigma. These alternatives range from a massive organizationwide launch that covers multiple facilities to a smaller scope, short- term project. The following is a list of deployment alter- natives ranging from large- scale organizational initiatives to smaller project- based launches.

• Corporate-wide launch • Single- facility launch • Department- based launch • Single- product– based launch • Project- based launch

Each method has advantages and disadvantages and the deployment mechanism should be selected based on the available resources (financial, employee, and technology), the project timeline, the project goals, and the corporate culture of the organization. Table 6.1 summarizes key benefits and drawbacks of each method.

For an organization just beginning the Lean Six Sigma process, the project- based launch is most often recommended. The primary reasons for this are that it requires fewer resources and has a shorter timeline. The key idea is that early quick results can lead to bigger projects in the future based on the success of smaller projects. A project is also easier to manage, for example, examining quality defects arriving from a single overseas supplier. Other advantages include:

48 Lean Six Sigma for Engineers and Managers: With Applied Case Studies

• Utilizes tools in a more focused and productive way

• Increases communication between management and practitioners • Facilitates a detailed understanding of critical business processes • Gives employees and management views of how Lean Six Sigma

tools can be of significant value to organizations

The central concept, regardless of which deployment method is chosen, is to tie project results into bottom line and quality benefits. The same concept is applied when prioritizing organizational needs or selecting among poten- tial projects. These benefits should be expressed in terms of key process out- put variables such as:

• Process variation • Process cycle time • Cost per unit

• Customer satisfaction • Scrap or defect rates

Several key concepts to keep in mind during the deployment planning phase include:

• Communicating the benefits of the project as a business strategy across the organization

• Aligning with management in the deployment of Lean Six Sigma • Building a successful infrastructure for Lean Six Sigma deployment TABLE 6.1

Deployment Method Benefits and Drawbacks

Benefits Drawbacks

Corporate-wide

launch 1. Biggest results 2. Consistent processes across the entire organization

3. Optimizes the entire business system 4. Economy of scale

1. Highest cost

2. Longest implementation time 3. Requires intensive planning 4. Requires intensive data

collection Single facility

launch 1. Can be used as a pilot project for other facilities 2. Analyzes entire facility for complete

optimization

1. High cost

2. Requires intensive data collection

Department-

based launch 1. Simplified implementation analysis 2. Promotes departmental team work 1. Can miss opportunities in other departments Single- product–

based 1. Analyzes more than just emissions from a facility 1. Data collection intensive Project- based

49 Deployment Alternatives

• Selecting and implementing successful Lean Six Sigma projects and project teams

• Utilizing the right metric to drive the right activity • Planning and execution of projects

• Selecting the right statistical tools

Finally, the recommended overall approach to the deployment of Lean Six Sigma is based on proven Six Sigma methodologies. The Six Sigma process involves the DMAIC methodology described below:

DEFINE

Define and clarify the project goal and timeline. Establish a cross- functional team.

MEASURE

Define the current state and current processes, including the devel- opment of a process flow map to baseline the system and to iden- tify any bottlenecks.

Collect and display data including task time, resources required, and process statistics.

ANALYZE

Determine process capability and speed utilizing statistical tools and charts.

Determine sources of variation and subsequent time bottlenecks. Identify and quantify value- added and non-value-added activities. IMPROVE

Generate ideas.

Conduct experiments and validate improved processes. Develop action plans and standard operating procedures. CONTROL

Develop control plan. Monitor performance. Mistake- proof processes.

This provides a brief introduction to the general approach for deploying Lean Six Sigma using Six Sigma. A detailed overview of the Lean Six Sigma implementation road map is discussed in Chapter 8.

50 Lean Six Sigma for Engineers and Managers: With Applied Case Studies