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CHAPTER 11 Six Sigma and Process Improvement Teaching Notes This chapter brings the Six Sigma concept into a sharp focus, and builds on the need to integrate a performance management framework with operational requirements in managing quality. In this chapter, we introduce the statistical basis for Six Sigma, and outline the requirements for Six Sigma implementation. This chapter also extends the concepts of Chapter 10 on statistical thinking and introduces the 7 QC Tools used for kaizen -- continuous improvement -- Six Sigma and “lean” projects. Key objectives for this chapter should be to assist students: To fully understand the concept of breakthrough, defined as the accomplishment of any improvement that takes an organization to unprecedented levels of performance. Six Sigma projects often focus on breakthrough improvements that add value to the organization and its customers through systematic approaches to problem solving. To become aware of the tools and techniques of Six Sigma which represent a collection of quality improvement and statistical methods and have been used successfully over the years in generic TQM initiatives, ISO 9000, and in Baldrige processes. 1

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Chapter 10 - Quality Improvement 2

Six Sigma and Process Improvement 2

CHAPTER 11Six Sigma and Process ImprovementTeaching NotesThis chapter brings the Six Sigma concept into a sharp focus, and builds on the need to integrate a performance management framework with operational requirements in managing quality. In this chapter, we introduce the statistical basis for Six Sigma, and outline the requirements for Six Sigma implementation. This chapter also extends the concepts of Chapter 10 on statistical thinking and introduces the 7 QC Tools used for kaizen -- continuous improvement -- Six Sigma and lean projects. Key objectives for this chapter should be to assist students:

To fully understand the concept of breakthrough, defined as the accomplishment of any improvement that takes an organization to unprecedented levels of performance. Six Sigma projects often focus on breakthrough improvements that add value to the organization and its customers through systematic approaches to problem solving.

To become aware of the tools and techniques of Six Sigma which represent a collection of quality improvement and statistical methods and have been used successfully over the years in generic TQM initiatives, ISO 9000, and in Baldrige processes. To learn that a defect, or nonconformance, is any mistake or error that is passed on to the customer. A unit of work is the output of a process or an individual process step. A common measure of output quality is defects per unit (DPU), computed as Number of defects discovered/Number of units produced, and in Six Sigma metrics, defects per million opportunities (dpmo) = DPU ( 1,000,000/opportunities for error. A six-sigma quality level corresponds to at most 3.4 dpmo which is equivalent to a process variation equal to half of the design tolerance, while allowing the mean to shift as much as 1.5 standard deviations from the target. The sigma level can easily be calculated on a spreadsheet using the Excel formula =NORMSINV(1 Number of Defects/Number of Opportunities) + SHIFT or equivalently, =NORMSINV(1 dpmo/1,000,000) + SHIFT To learn about and practice problem solving -- correcting deviations between what is happening and what should be happening. Quality related problems often fall into five categories: conformance problems, unstructured performance problems, efficiency problems, product design problems, and process design problems. To appreciate that a structured problem solving process provides employees and teams with a common language and a set of tools to communicate with each other. To develop understanding of the Six Sigma stages of: 1) Define - the process of drilling down to a more specific problem statement is sometimes called project scoping; 2) Measure - collecting good data, observation, and careful listening; 3) Analyze - focuses on why defects, errors, or excessive variation occur, and focuses on the root cause; 4) Improve - focuses on idea generation, evaluation, and selection; 5) Control - focuses on how to maintain the improvements.

To appreciate that projects are the vehicles that are used to organize team efforts and to implement the DMAIC process. Being able to manage a large portfolio of projects, as would be found in Six Sigma environments, is vital to organizational success.

To study factors that should be considered when selecting Six Sigma projects including: financial return, impacts on revenues and market share, impacts on customers and organizational effectiveness, probability of success, impacts on employees, and strategic fit.

To introduce Six Sigma tools, in the light of two unique features of DMAIC: its emphasis on customer requirements and the disciplined use of statistical and other types of improvement tools. Typical types of tools include elementary statistical tools, advanced statistical tools, product design and reliability, measurement, process control, process improvement, and implementation and teamwork. To become familiar with, and learn to apply the "seven QC tools" and related tools for quality problem solving. The seven tools include flowcharts or process maps, run charts, data sheets or check sheets, histograms, cause-and-effect diagrams, Pareto diagrams, scatter diagrams and control charts. To introduce the concept of lean production which refers to approaches initially developed by the Toyota Motor Corporation that focus on the elimination of waste in all forms, including defects requiring rework, unnecessary processing steps, unnecessary movement of materials or people, waiting time, excess inventory, and overproduction. In service contexts, lean production is often called lean enterprise. Some of the key tools used in lean production are the 5Ss; visual controls; efficient layout and standardized work; pull production; single minute exchange of dies (SMED); total productive maintenance; source inspection; and continuous improvement. To comprehend that tools and approaches used in Six Sigma and lean production are different, yet complementary. Lean is focused on efficiency by reducing waste and improving process flow while Six Sigma is focused on effectiveness by reducing errors and defects. Lean Six Sigma is a synthesis of the best practices of both Six Sigma and lean production and has gained considerable favor among practitioners in many organizations. To appreciate that although Six Sigma was developed in the manufacturing sector, it can easily be applied to a wide variety of transactional, administrative, and service areas. Within the service sector, Six Sigma is beginning to be called transactional Six Sigma. However, differences between services and manufacturing make opportunities in services more difficult to identify, and projects more difficult to define. Small organizations can use Six Sigma, although perhaps in a more informal fashion.

The Instructors Resource section of the website accompanying this text has a number of Baldrige video clips which give an inside view of organizations that have received the Baldrige award. Some of these, that are especially appropriate for this chapter, have scenes that show how process improvement approaches can enhance an organizations quest for world-class quality.

ANSWERS TO QUALITY IN PRACTICE KEY ISSUES

An Application of Six Sigma to Reduce Medical Errors

1.Process mapping was an essential early step for Froedtert Hospital to take in order to identify the points at which failures in the IV infusion process could possibly take place. When combined with the FMEA, it provided clues as to where errors were generated, their severity, and suggested the next steps to be taken for measurement, in order to point the way toward control and improvement.

2.The teams and task forces were multidisciplinary because the processes crossed organizational boundaries. For example, the IVs could be used in emergency rooms, surgical theatres, maternity wards, etc. They would be of interest and concern to physicians, nurses, pharmacists, and administrators, as pointed out in the case. The approach has the benefit of bringing people with different perspectives and expertise together to work on a complex problem, which may not be fully understood by any one person or smaller group of people.

Applying Quality Improvement Tools to an Order Fulfillment Process

1.The DMAIC process from this chapter, and the Deming cycle and the creative problem-solving process from an earlier chapter are basically parallel statements of statistical thinking used to solve problems.

Although not a perfect fit these processes can be compared in a parallel fashion as follows:

Six SigmaDemingCreative Problem-solving

DefinePlanUnderstanding the "mess"

MeasureDoFinding facts

AnalyzeStudyIdentifying specific problems

Generating ideas

ImproveDeveloping solutions

ControlActImplementation

In the case study the team defined the problem (initially) as discover ways to reduce order processing time so that at least 98% of orders would be shipped on time (within 24 hours of receipt). They then sought to understand the process by gathering facts the data of times for processing 50 orders. They then analyzed the data in a search for the causes for variation and select the most likely cause. Once they discovered that order-picking was the bottleneck operation, they could generate ideas and test them for effectiveness in solving the problem. They found out that their first solution did not work well. They had to use a longer cart, rather than wider one in order to become more efficient in the order-picking step in the process. Once they had tested their improvement they undertook a longer study of effectiveness to prove the solution.

2.Although not mentioned in the case, Deming would suggest that the cycle could be repeated over and over for continuous improvement. Therefore, if sufficient time had not been shaved off the average time for picking each order, then additional analysis might produce further methods improvements to reduce the time.

3.Alternatively, the packing process might be examined for improvements. The same set of problem-solving steps should be used to gather facts, analyze the facts, develop ideas for improvement, test the proposed solution, and make it a part of the entire order picking process.

BONUS MATERIALS - QUALITY IN PRACTICEImproving Patient Services at Middletown Regional Hospital

Note: Data from Press Ganey surveys, mentioned in the body of the case, are available in spreadsheet MRHCase.xls on the instructors website for this chapter. Instructors may choose to make these data available to the students for more detailed analysis.Key Issues for Discussion

1.The Deming Cycle of Plan-Do-Study-Act is certainly covered by the steps of Middletown Regional Hospitals Total Quality Improvement Implementation System. Planning is done using steps 1-3 of MRHs process. Organizational awareness and environmental transformation are used as preparation for identifying and defining the problem. The Do part of the Deming Cycle is performed during steps 4 and 5 of MRHs process. The Study phase of the Deming process takes place in step 6, analysis, of MRHs process. The Deming Act phase takes place in step 6, make recommendations, of MRHs process. Follow-up on actions taken is the step 7 requirement of MRHs process, to re-measure in order to assess improvement. Coverage of Demings Act phase does not indicate whether or not a pilot study is usually performed before action is taken to implement the change systemwide.The DMAIC process may be an even better fit for MRHs process. Define, Measure, Analyze, Improve, and Control are covered by steps 1-3 of MRHs process (define); steps 4 and 5 (measure); step 6 (analyze and improve); and step 7 (control).

2.EVS has used checksheets (from the Press Ganey surveys), control charts and correlation matrixes to analyze the problem situation. This combination has provided more insights into the nature of the problem and possible solutions than as single technique would have done.

3.Another insight from analysis of graphs developed from the Press Gainey surveys stems from the fact that there is very little variability in results over the 11-quarter period. This indicates a very stable process, but also indicates that changes that were made had little impact. The root cause for not being able to raise satisfaction levels still has not been found. Approaches to service recovery should be explored, as well as after the fact determination of quality deficiencies.

4.These three initiatives have helped to slightly reduce the gap between managements goals and the actual customer perceptions. This is what a control and improvement system is supposed to do. However, the gap has not yet been completely closed.

5. Other approaches that EVS might try in order to close the gap would be to benchmark the hotel industry (perhaps by visiting The Ritz-Carlton Hotel Company), develop a fast feedback form that would help identify strengths and OFIs and could be acted on while the patient was still in the facility, and do in-depth interviews with patients upon their discharge.

Six Sigma at National Semiconductor

1. An example of how National Semiconductor applied the DMAIC process was at the South Portland, Maine, facility, which produces advanced CMOS devices. The site saw an opportunity to improve yields on a 0.35-m fabrication process by finding and eliminating sources of variation in the manufacturing flow.

Define

The fab was experiencing losses at the final electrical test (ET) operation. An 18-week baseline study of ET yield showed that there was an opportunity for approximately 1.5 percent additional yield for all wafers in this technology, meaning that they were leaving more than $1 million in profit on the table. The goal of eliminating the systematic yield loss caused by transistor leakage and gate oxide breakdown was set. The team was also challenged to establish a control plan for measurement of critical-to-function parameters in the process flow that could be used to prevent failing wafers from getting to the final ET step.

Measure

Analysis of the reasons for failed wafers at electrical test identified three process modules that showed excessive variation in the fabrication process. These modules included the spacer formation, channel implants, and post-implant acid cleaning steps. Other suspect areas were eliminated by performing commonality studies on past events, discussing the issue with industry experts, and re-evaluating experiments that had been previously run.

Analyze

Analysis revealed seven factors were determined to have an effect on the three key failure modes. Utilizing the design of experiments (DOE) function of JMP statistical software, the team developed three experiments to determine which interactions had the greatest effect on yield.

Improve

Prior to running the DOEs, the team had already collected enough information to know that tighter controls were needed on certain in-fab process parameters in the transistor modules. By taking early action to put these controls in place, the team was able to realize some yield improvements after only two months. Once the DOE results came out, the team was able to validate the earlier actions and fully characterize the process window for these critical steps. In the improve step, the team leveraged the results of the DOEs performed during the previous (analyze) step to make necessary changes to specs, procedures, and equipment. These changes ensured that variation during the spacer, implant, and acid cleaning steps wouldnt affect yield at electrical test.

Control

To ensure that the process improvements developed by the team became permanent, a control plan was created and transferred to the manufacturing group, defining the requirements for every critical-to-function parameter in terms of control charts, control limits, sampling plans, gage capability, and out-of-control action plans. By implementing improved process control methods, the team was able to surpass the initial goal, provide Nationals designers with a competitive advantage in their efforts to develop new products for the analog marketplace, and increase yield by more than 1.5 percent, with a projected annual savings of $1.1 million. The project lasted about nine months.

2. National Semiconductor produces highly complex integrated circuits that generally require clean-room technology to avoid quality problems. With all of these complex processes, isolating and reducing variables is a Herculean taskone that is perfect for Six Sigma. National Semiconductor has a field defective rate of less than 20 defective parts per million, but it still saw room for improvement, particularly in the area of internal yield. Kamal Aggarwal, executive V.P. of the CTMG, mandated that all CTMG units would deploy Six Sigma.

It took a number of initiatives, in at least six stages, to build momentum and establish the Six Sigma process. 1) A large CTMG-wide continuous improvement (CI) effort yielded good results, but it suffered from inconsistency. Each unit -- three wafer fabs, three assembly sites, and the CTMG headquarters in Santa Clara, California used its own methods to improve quality. 2) So National Semiconductor invited GE Consulting to help with implementing Six Sigma, but the idea met with resistance, because the employees felt that they were already using Six Sigma tools and believed that they were quite good at it. 3) Then, a year later, another consulting firm that had experience in high-tech processes was brought in to reintroduce Six Sigma. They convinced the senior V.P. of Nationals plant in Melaka, Malaysia, to launch a pilot Six Sigma program with 10 projects. 4) Nine months later at the next CTMG Summit, a key National Semiconductor supplier, DuPont Electronic Technologies, made a presentation on how to quantify Six Sigma. This, coupled with the results of the 10 Melaka pilot projects (initial savings of nearly $900,000 and projected annual savings of nearly $2.3 million), convinced Aggarwal to implement Six Sigma across CTMG. 5) The first wave of projects began in June 2003. Since then, 52 projects have been completed with an 84 percent success rate, resulting in tens of millions of dollars in both hard and soft savings. 6) In March 2004, CTMG launched its second wave of Six Sigma programs, targeting similar savings from 44 projects. Four of these projects target issues that exist on multiple sites, whereas nine are aimed at customer satisfaction, quality, or safety improvement.

Although not addressed by this case, chances are that National Semiconductor is a high-performing company based on various financial and quality measures (see Ch. 9). If that is the case, research indicates that best practices should include: providing customer-relationship training for new employees, emphasizing quality and teamwork for senior management assessment, encouraging widespread participation in quality meetings among non-management employees, using world-class benchmarking, communicating strategic plans to customers and suppliers, conducting after-sales service to build customer loyalty, and emphasizing competitor-comparison measures and customer satisfaction measures when developing plans. The key to establishing the Six Sigma process at National Semiconductor was executive support at several levels. It seems likely that outstanding effort in the form of team participating in quality meetings, world-class benchmarking, and communicating strategic plans, relating to quality, to customers also played a part in the eventual success of the Six Sigma initiative and related projects.

Answers to Review Questions

1.A six sigma quality level corresponds to a process variation equal to half of the design tolerance (in terms of the process capability index, Cp = 2.0) while allowing the mean to shift as much as 1.5 standard deviations from the target, which is the manufacturing specification. The allowance of a shift in the distribution is important, since no process can be maintained in perfect control, due to natural variation.2.The recognized benchmark for Six Sigma implementation is General Electric. GEs Six Sigma problem solving approach (DMAIC) employs five phases:a) Define (D)

i) Identify customers and their priorities.

ii) Identify a project suitable for Six Sigma efforts based on business objectives as well as customer needs and feedback.

iii) Identify CTQs (critical to quality characteristics) that the customer considers to have the most impact on quality.

b) Measure (M)

i) Determine how to measures the process and how is it performing.

ii) Identify the key internal processes that influence CTQs and measure the defects currently generated relative to those processes

c) Analyze (A)

i) Determine the most likely causes of defects.

ii) Understand why defects are generated by identifying the key variables that are most likely to create process variation.

d) Improve (I)

i) Identify means to remove the causes of the defects.

ii) Confirms the key variables and quantify their effects on the CTQs.

iii) Identify the maximum acceptable ranges of the key variables and a system for measuring deviations of the variables.

iv) Modify the process to stay within the acceptable range.

e) Control

i) Determine how to maintain the improvements.

ii) Put tools in place to ensure that the key variables remain within the maximum acceptable ranges under the modified process.

Note that this approach is similar to the other quality improvement approaches we discussed and incorporates many of the same ideas. The key difference is the emphasis placed on customer requirements and the use of statistical tools and methodologies.

3.There are significant differences between project selection and problem definition. Project selection generally responds to symptoms of a problem and usually results in a rather vague problem statement. In project definition, one must describe the problem in operational terms that facilitate further analysis. For example, a firm might have a history of poor reliability of electric motors it manufactures, resulting in a Six Sigma project to improve motor reliability. A preliminary investigation of warranty and field service repair data might suggest that the source of most problems was brush wear, and more specifically, suggest a problem with brush hardness variability. Thus, the problem might be defined as reduce the variability of brush hardness. This process of drilling down to a more specific problem statement is sometimes called project scoping.

4.NCR Corporation defines root cause as that condition (or interrelated set of conditions) having allowed or caused a defect to occur, which once corrected properly, permanently prevents recurrence of the defect in the same, or subsequent, product or service generated by the process. As with a medical analogy, eliminating symptoms of problems usually provides only temporary relief; eliminating root causes provides long-term relief.

A useful approach for identifying the root cause is the 5 Why technique. This approach forces one to redefine a problem statement as a chain of causes and effects to identify the source of the symptoms by asking Why? (ideally five times). In a classic example at Toyota, a machine failed because a fuse blew. Replacing the fuse would have been the obvious solution; however, this would have only addressed the symptom of the real problem. Why did the fuse blow? Because the bearing did not have adequate lubrication. Why? Because the lubrication pump was not working properly. Why? Because the pump axle was worn. Why? Because sludge seeped into the pump axle this was the root cause. Toyota attached a strainer to the lubricating pump to eliminate the sludge, thus correcting the problem of the machine failure.

5.Several key principles are necessary for effective implementation of Six Sigma:

a) Committed leadership from top management.

b) Integration with existing initiatives, business strategy, and performance measurement.

c) Process thinking.

d) Disciplined customer and market intelligence gathering.

e) A bottom-line orientation.

f) Leadership in the trenches.

g) Continuous reinforcement and rewards.

6.The tools used in Six Sigma efforts have been around for a long time. What is unique about Six Sigma is the integration of the tools and methodology into management systems across the organization. The topics covered may be categorized into seven general groups:

a) Elementary statistical tools (basic statistics, statistical thinking, hypothesis testing, correlation, simple regression)

b) Advanced statistical tools (design of experiments, analysis of variance, multiple regression)

c) Product design and reliability (quality function deployment, failure mode and effects analysis)

d) Measurement (process capability, measurement systems analysis)

e) Process control (control plans, statistical process control)

f) Process improvement (process improvement planning, process mapping, mistake proofing)

g) Implementation and teamwork (organizational effectiveness, team assessment, facilitation tools, team development)

7.Successful quality improvement depends on the ability to identify and solve problems. According to Kepner and Tregoe, a problem is a deviation between what should be happening and what actually is happening that is important enough to make someone think the deviation ought to be corrected. Problem solving is the activity associated with changing the state of what is actually happening to what should be happening.8.All quality problem-solving can be classified into the following five categories:

a.Conformance problems are defined by unsatisfactory performance by a well-specified system. Users are not happy with system outputs, such as quality or customer service levels. Traditional quality improvement tools and Six Sigma methods are often used here.

b.Efficiency problems result from unsatisfactory performance from the standpoint of stakeholders other than customers. Typical examples are cost and productivity issues. Lean tools are often used to address such problems.

c.Unstructured performance problems result from unsatisfactory performance by a poorly specified system. That is, the task is nonstandardized and not fully specified by procedures and requirements. Unstructured problems require more creative approaches to solving them.

d.Product design problems involve designing new products that better satisfy user needsthe expectations of customers that matter most to them. For such problems, Design for Six Sigma (see Chapter 12) tools and methods are applicable.

e.Process design problems involve designing new processes or substantially revising existing processes. The challenge here is determining process requirements, generating new process alternatives, and linking these processes to customer needs. Work systems design approaches discussed in Chapter 7 are typically used.9.The Seven QC (quality control) Tools include flowcharts, check sheets, histograms, Pareto diagrams, cause-and-effect diagrams, scatter diagrams, and control charts. These tools support quality improvement problem solving efforts.

In the CPS process, these tools will be useful in charting and understanding messes. They can help in finding and recording facts and in identifying specific problems. Once solution ideas have been generated, these ideas can be added to the QC Tools to produce what if we? scenarios. Problem solvers can use the tools in cause-and-effect scenarios to figure out which solutions will work, and which ones will not.

10.Flowcharts are best developed by having the people involved in the processemployees, supervisors, managers, and customersconstruct the flowchart. A facilitator provides objectivity in resolving conflicts. The facilitator can guide the discussion through questions such as What happens next?, Who makes the decision at this point?, and What operation is performed at this point? Quite often, the group does not universally agree on the answers to these questions due to misconceptions about the process itself or a lack of awareness of the big picture.

Flowcharts help all employees understand how they fit into a process and who are their suppliers and customers. This realization then leads to improved communication among all parties. Flowcharts also help to pinpoint places where quality-related measurements should be taken. Once a flowchart is constructed, it can be used to identify quality problems as well as areas for productivity improvement. Questions such as How does this operation affect the customer?, Can we improve or even eliminate this operation? or Should we control a critical quality characteristic at this point? trigger the identification of opportunities.

11.A control chart is simply a run chart to which two horizontal lines, called control limits are added: the upper control limit (UCL) and lower control limit (LCL). Control limits are chosen statistically so that there is a high probability (generally greater than 0.99) that points will fall between these limits if the process is in control. Control limits make it easier to interpret patterns in a run chart and draw conclusions about the state of control.

A run chart is a line graph in which data are plotted over time. The vertical axis represents a measurement; the horizontal axis is the time scale. Run charts show the performance and the variation of a process or some quality or productivity indicator over time. They can be used to track such things as production volume, costs, and customer satisfaction indexes. Run charts summarize data in a graphical fashion that is easy to understand and interpret, identify process changes and trends over time, and show the effects of corrective actions.

12.Check sheets are simple tools for data collection. Nearly any kind of form may be used to collect data. Data sheets are simple columnar or tabular forms used to record data. However, to generate useful information from raw data, further processing generally is necessary. Check sheets are special types of data collection forms in which the results may be interpreted on the form directly without additional processing.

In manufacturing, check sheets similar to Figure 11.9 are simple to use and easily interpreted by shop personnel. Including information such as specification limits makes the number of nonconforming items easily observable and provides an immediate indication of the quality of the process. For example, in Figure 11.9 a significant proportion of dimensions are clearly out of specification, with a larger number on the high side than the low side.

A second type of check sheet for defective items is illustrated in Figure 11.10, which shows the type of defect and a tally in a resin production plant. Such a check sheet can be extended to include a time dimension so that data can be monitored and analyzed over time and trends and patterns, if any, can be detected. Figure 11.11 shows an example of a defect location check sheet.

13.A histogram is a basic statistical tool that graphically shows the frequency or number of observations of a particular value or within a specified group. Histograms provide clues about the characteristics of the parent population from which a sample is taken. Patterns that would be difficult to see in an ordinary table of numbers become apparent.

The Pareto principle was observed by Joseph Juran in 1950. Juran found that most effects resulted from only a few causes. Pareto analysis clearly separates the vital few from the trivial many and provides direction for selecting projects for improvement. Pareto analysis is often used to analyze data collected in check sheets. A Pareto distribution is one in which the characteristics observed are ordered from largest frequency to smallest. A Pareto diagram is a histogram of the data from the largest frequency to the smallest.14.The cause-and-effect diagram was introduced in Japan by Kaoru Ishikawa. It is a simple, graphical method for presenting a chain of causes and effects and for sorting out causes and organizing relationships between variables. Because of its structure, it is often called a fishbone diagram. The general structure of a cause-and-effect diagram is shown in Figure 11.15. At the end of the horizontal line, a problem is listed. Each branch pointing into the main stem represents a possible cause. Branches pointing to the causes are contributors to those causes. The diagram identifies the most likely causes of a problem so that further data collection and analysis can be carried out.15.Scatter diagrams are the graphical component of regression analysis. While they do not provide rigorous statistical analysis, they often point to important relationships between variables, such as the percentage of an ingredient in an alloy and the hardness of the alloy. Typically, the variables in question represent possible causes and effects obtained from Ishikawa diagrams.

16.Some of the tools and approaches used for lean operations in organizations include: the 5Ss; visual controls; efficient layout and standardized work; pull production; single minute exchange of dies (SMED); total productive maintenance; source inspection; and continuous improvement. Six Sigma is a useful and complementary approach to lean production where the concepts might be used in combination, in order to reduce cycle times, streamline an order entry processes, or drill down to the root causes of the problems and identify solutions. Because of their similarities, many industry training programs and consultants have begun to focus on Lean Six Sigma, drawing upon the best practices of both approaches. Both are driven by customer requirements, focus on real dollar savings, have the ability to make significant financial impacts on the organization, and can be used in non-manufacturing environments.

However, lean and Six Sigma concepts are different. They attack different types of problems. Lean production addresses visible problems in processes, for example, inventory, material flow, and safety, while Six Sigma is more concerned with less visible problems, for example, variation in performance. Another difference is that lean tools are more intuitive and easier to apply by anybody in the workplace, while many Six Sigma tools require advanced training and expertise of Black Belt or Master Black Belt specialists, or consultant equivalents. The concept of the 5Ss is easier to grasp than statistical methods.

17.Small organizations are often confused and intimidated by the size, costs, and extensive technical training they see in large organizations that implement formal Six Sigma processes. Because of this, they often they dont even try to adopt these approaches. Small organizations are usually lean by necessity, but their processes often operate at quality levels of two to three sigma, and they are not even aware of it. Small organizations thinking about adopting Six Sigma or lean production are advised to: Obtain management commitment

Identify key processes and goals

Prioritize the improvement projects

Be systematic

Dont worry about training Black and Green Belts

Use just-in-time practices to learn the Six Sigma tools necessary to successfully carry out specific projects

Communicate successes and reward and recognize performers

Small companies often need to bring in consultants for training or improvement initiatives in the early stages of learning. This can help to develop in-house expertise and put them on the right track.

Discussion Questions

1.As with many other criticisms of quality improvement efforts, this Fortune article focuses on what happens if organizations fail to apply the basic quality concepts to so-called improvement initiatives. Deming frequently said: There is no instant pudding. in making quality work. Thus, the statements in the article are largely bogus.

a. If Six Sigma has no noticeable impact on company financial statements, its because not many home runs (large return) projects have been done. One of the strengths of the Six Sigma concept is that it documents financial impacts of the projects.

b. It is unclear why only early adopters can benefit, since every organization has its own unique set of process and opportunities will differ from any other organization. Thus any organization should be able to benefit from Six Sigma process improvements.

c. Yes, defects are more difficult to define and measure for service organizations than for manufacturing, but numerous service organizations (such as Baldrige winners) have proven that it is possible and profitable to do so.

d. Six Sigma cannot guarantee that your product will have a market, but nothing else can guarantee it, either, -- other than continuous innovation and continuous improvement (of which Six Sigma can be a vital part).

2. Six Sigma projects can be devised to improve activities and processes in such areas as:

Sales and marketing projectsPerceived product value

Overall customer satisfactionSales force effectivenessComplaint reductionGains and losses of customersCustomer awards/recognitions

Supply chain management projects

Internal supplier quality measurements

Defect levels

Response time

Customer ratings of prod/service performance

Managing information technology projects

Internal information technology quality measurements

Defect levels

Response time

Customer ratings of service performance

Improvement of procurement process for software and hardware

Human resource projectsRoot cause analysis and reduction of absenteeism

Root cause analysis and reduction of turnover

Measurement and improvement of employee satisfaction

Measurement and improvement of training effectiveness

Grievance reduction

Suggestion system improvement

Safety improvement

3.A set of CTQs that might influence overall service satisfaction for service at an automobile dealership includes the dimensions of service quality found in Chapter 4, as well as a couple of related ones (timeliness and time):

Empathy ability to understand and empathize with the problems of customers who may or may not have the technical know-how to explain them in mechanical terms

Timeliness return of the car at the time promised is essential to busy customers

Time the amount of time required is related to the size of the repair bill

Assurance with limited technical proficiency, customers have to feel comfortable relying on the expertise of the repair staff

Reliability customers wan the problems fixed right, the first time, so that they dont have to keep returning, over and over, for the same problem

Responsiveness customers would like to have answers as to how, when and where a repair can be done, by a responsive service representative

Tangibles last, but perhaps not least, customers would like to see clean, attractive work areas, waiting areas, and toilet facilities

4.Resistance to change is to be expected in introduction of a new approach, such as Six Sigma, and plays a key part in successful adoption of the concept. As pointed out in Chapter 6, keys to overcoming resistance to change, more often held by managers than by first-line employees, are: a) early involvement by all parties, b) open and honest dialogue, and c) good planning. Managers must believe in workers and their ability to contribute. Workers, of course, must believe that managers will support the change to empower them and help them to learn new skills required to be effective contributors. Managers must also show commitment to the practices of EI, such as training, rewards, and recognition. Thus, adoption of Six Sigma cannot be successful in the long run without supervisor and employee buy-in. 5.Processes that students might encounter at their college or university due to part-time work on campus might include accounting, budgeting, purchasing, training and development, and research. Non-educational institutions they might benchmark might be hospitals (accounting); relief agencies, such as the Red Cross (budgeting); discount stores (purchasing); consulting firms (training and development); and pharmaceutical firms (research and development).

In addition students in this course might be assigned the personal TQM project (see Chapter 1 for details) and asked to identify a number of objectives for improvement. Some typical objectives are get up on time (no snooze alarm), study chapters before coming to class, eat no more than one junk food item out of the vending machine each day, etc. Students might use the DMAIC process in order to make improvements. To do so, they would need to define the critical to quality characteristics that they desired (such as those things that contribute to higher grades), decide how to measure and analyze them (using a PTQM checksheet and scatter diagrams, for example), and then deciding on required improvements and a control process to hold the gains.

6. Companies today face incredible pressures to continually improve the quality of their products while simultaneously reducing costs, to meet ever-increasing legal and environmental requirements, and to shorten product life cycles to meet changing consumer needs and remain competitive. The ability to achieve these goals depends on a large extent on product design. The complexity of todays products makes design a difficult activity; a single state-of-the-art integrated circuit may contain millions of transistors and involve hundreds of manufacturing steps. Thus six sigma quality levels are difficult to attain, due to multiple variables that may affect quality. Nevertheless, improved designs not only reduce costs, but also increase quality.7.The appropriate tools to attack the problems would be:

a. If the significant causes of the copier jams are known, use a flowchart to show the method for clearing each type of jam so that users would know how to fix them.

b. Use a cause-effect diagram to identify the problem and to focus in on the most significant one in the engineering publications.

c. Gather data using a checksheet to identify the significant causes of errors with the laser printer, and then use a Pareto diagram to graph them.

d. Use a scatter diagram to see if the weights show a stable pattern. If a weight reduction program is not needed and the process is stable, plot the weight results on a control chart.

e. Use process simulation to determine the number of positions of different types.

f. Use a scatter diagram and do a correlation analysis between changes and dollar value, or changes and days between the request for proposal and contract award.

g. Use a scatter diagram and do a regression analysis by time of year, in order to predict staffing needs.

8.Lean concepts similar to those used in small businesses may have applicability to classrooms, such as:

Obtain administrative commitment

Identify key processes and goals

Prioritize the improvement projects

Be systematic

Dont worry about training Black and Green Belts

Use just-in-time practices to learn the Six Sigma tools necessary to successfully carry out specific projects

Communicate successes and reward and recognize performers

9.Ideally, the skills of technical experts (Green or Black Belts) will complement those of team members (often called subject matter experts, or SMEs). The two types of experts may be at odds if they cannot agree ways to analyze problems, what their measures show, and how to implement improvements and hold the gains through appropriate control techniques. To prevent them from clashing in such a way as to harm the results of the Six Sigma process, it is useful to see that each has training and/or orientation to the environmental factors, methods, and concepts used by the others. Also, the project champion has responsibility to see that any disputes are mediated and resolved in such a way as to enhance project success. 10.The DMAIC process for a registration process design/improvement should begin with customer needs and expectations (expected quality), and end with what the customer sees and believes the quality of the product to be (perceived quality). These might include characteristics as follows:

Attributes

Technical Requirements

Convenience

Time, dates, internet, phone

Speed

Process standards

Costs

Fees

Accuracy

Error prevention

Empathy

Understanding/willingness of

personnel to solve problems

Expected quality needs to be considered in the Define stage based on what the customer assumes will be received from the process as a reflection of the customer's needs. The university must focus on the key dimensions that are reflected in specific customer needs. If these expectations are not identified correctly or are misinterpreted, then the final product will not be perceived to be of high quality by customers. For registration, this will typically involve availability of classes, timeliness of the process, time required to complete the process, etc.

Technical requirements determine the design quality of the product. Process designers' must Measure and Analyze not only the technical requirements for providing and registering students for courses, but also perceptions of their needs, which may differ from what is feasible. Other customers of the process also have some CTQ issues that registration process designers must be aware of. For instance, while the "average" student might need general courses, curriculum majors may need in depth or specialized courses. If registration process designers never have an opportunity to interact with customers (students, academic department administrators, faculty), the probability that they will not understand or will misinterpret the expected delivery requirements and expected quality is greatly increased.

After the registration process design is transferred to people or organizational units responsible for delivering the service, poor attention to customer needs can affect the perceived quality. For example, if the system is not designed to assure conformance to the technical specifications, then the actual quality produced may not be the same as the design quality. The equation that relates these different levels of quality is: perceived quality = actual quality - expected quality. These characteristics must be taken into account when the Improve and Control phases are completed.

Admission processes have many of the same process considerations as registration. However, the needs of certain stakeholders, such as potential students and parents of students, must also be taken into account.11.To balance the who, what, where, when why, and how of Six Sigma implementation, a manager, assisted by the team, must evaluate them and select the most promising. This includes confirming that the proposed solution will positively impact the key process variables and the CTQs, and identifying the maximum acceptable ranges of these variables. Since problem solutions often entail technical or organizational changes, some sort of decision or scoring model may be used to assess possible solutions against important criteria. These may include: cost, time, quality improvement potential, resources required, effects on supervisors and workers, and barriers to implementation such as resistance to change or organizational culture. To implement a solution effectively, responsibility must be assigned to a person or a group who will follow through on what must be done, where it will be done, when it will be done, and how it will be done.

12.An argument can be made on either side of the question. On the positive side, Welchs action could be taken as a clear signal that Six Sigma was going to be vital process at G.E. for both management development and continuous improvement. It is still alive and well in G.E., as of this writing, almost 15 years later. On the negative side, there are often unintended consequences of threats such as these, as managers seek to carry out the letter of such a mandate, rather than the spirit. 13.The problem of proposing changes in one area that cancels out gains in the other area would appear to be due to a lack of communication between the two project teams. However, it may also have indicated a weakness in defining the scope of the projects. The team leaders should have been aware of the other project going on. They should then have coordinated on boundaries so as to prevent overlap. Finally project champions should have been consulted on how to either expand or break out the projects before they were started, or soon afterward.

14.Phantom" capacity in service operations is the equivalent of the hidden factory in manufacturing. By simplifying or eliminating processes in banks or hospitals that require excessive waiting time, maintenance, and rework, actual capacity could be increased by 25 percent or more without investing in additional equipment.SOLUTIONS TO PROBLEMS

1.Wellplace Insurance Company set a standard that policy applications should be processed within three days of receipt. If, out of a sample of 1,000 applications, 65 fail to meet this requirement, at what sigma level is this process operating?ANS.The defect rate is 65/1000 = 0.065. This is the same as: 0.065 X 1,000,000 = 65,000 dpmo. From Table 11.1, we see that this is slightly better than 3 sigma with off centering of 1.5 sigma.

2.During one month, 35 preflight inspections were performed on an airplane at Southstar Airlines. Nine nonconformances were noted. Each inspection checks 30 items. What sigma level does Southstar maintain if this incidence of nonconformance is typical of their entire fleet of airplanes? ANS. To calculate the dpmo, we use 9/35 to get the number of defects per unit (DPUs). However, 30 opportunities per aircraft checked must be taken into consideration, as shown, in order to calculate dpmo.

dpmo = (18/35) X 1,000,000/30 = 8571.4, which is less than 4 sigma with off centering of 1.5 sigma.3.Over the last year 1,054 injections were administered at the Fairhealth clinic. Quality is measured by the proper amount of dosage as well as the correct drug. In two instances, the incorrect amount was given, and in one case, the wrong drug was given. At what sigma level is Fairhealths process? ANS.We use 3/1054 to get the number of defects per unit (DPUs). However, there are 2 opportunities per injection (wrong drug, wrong dosage) to make an error. They must be considered, in order to calculate dpmo.

dpmo = (3/1054) X 1,000,000/2 = 1423.1, which is slightly less than 4.5 sigma with off centering of 1.5 sigma.

4.A few years back, the Wall Street Journal reported that about 750,000 airplane components are manufactured, machined, or assembled for Boeing Co. by workers from the Seattle Lighthouse for the Blind. A Boeing spokeswoman noted that the parts have an exceptionally low rejection rate of one per thousand. At what sigma level is this process operating?ANS. There is no indication of how many opportunities for defects there are per component, so we will have to assume that the defect rate is 1 per 1000 units produced. Therefore, only 750 defective items (0.001 X 750,000) were produced. To calculate dpmo, we see:dpmo = (1/1000) X 1,000,000 = 1000, which is slightly better than 4.5 sigma with off centering of 1.5 sigma.

5.Broadwork Electronics manufactures 500,000 circuit boards per month. A random sample of 5,000 boards is inspected every week for five characteristics. During a recent week, two defects were found for one characteristic, and one defect each was found for the other four characteristics. If these inspections produced defect counts that were representative of the population, what is the overall sigma level for this Broadwork process? What is the sigma level for the characteristic that showed two defects?

ANS. To calculate the overall dpmo and sigma level, we have:

dpmo = (6/5000) X 1,000,000/5 = 240, which is approximately 5 sigma with off-centering of 1.5 sigma.

But for the one characteristic, we have:

dpmo = (2/5000) X 1,000,000 = 400, which is still good, but somewhat less than 5 sigma with off centering of 1.5 sigma.

A Six Sigma project should be launched to determine root causes for the defects from this one characteristic.6.Outsource Microprocessor Corporation (OMC) sells 1500 specialized computer processing chips each month at a price of $1200 each. Variable costs amount to $1,000,000, and fixed costs are $400,000. Currently the company has a defect rate of 8 percent (which are chips returned by customers, scrapped by OMC, and replaced). Note that the variable costs include the cost of producing the defective chips.

a. What is the hidden cost to the company of making this rate of defectives instead of 1500 good chips each month?

b. Suppose a Six Sigma effort can reduce the defects to a six sigma level (assume for simplicity that the defective rate is essentially zero). What is the impact on profitability?

ANS. In order to produce and sell 1,500 good computer chips, OMC must start 1,500/0.92 = 1,631 chips into production. However, since the variable cost of $1,000,000 includes the cost of making scrap, the unit variable cost is therefore not $1,000,000/ 1,500 = $666.67 but $1,000,000/1,631 = $613.12. Thus the price paid for poor quality, sometimes called the hidden factory, is 131 x $613.12 = $80,319. This additional cost is incurred to make useless products that cant be sold.

If a quality improvement initiative achieves a six sigma defect level, the defective rate is essentially zero. This will remove the variable cost of making the 131 defective units. The table below shows that the $80,319 poor quality cost is eliminated from the variable costs, and the saved money trickles falls to the bottom line to increase profits. Thus, the profit increased to $480,319. The 8% reduction in operational costs produced a 20% increase in profit ($80,319/ $400,000).

Monthly BaselineMonthly Six Sigma Results

Sales1500 X $1200.00 =1800000

Sales1500 X $1200.00 =1800000

Variable Cost1631 X $ 613.12 =1000000

Variable Cost1500 X $ 613.12 = 919682

Contribution margin 800000

Contribution margin880319

Fixed cost

400000

Fixed cost400000

Net Profit

400000

Net Profit480319

Profit margin 0.222

Profit margin

0.267

7. A flowchart for a fast-food drive-through window is shown in Figure 11.25 (see text). Determine the important quality characteristics inherent in this process and suggest possible improvements.

ANS. The important quality characteristics for this drive-through window are: the machinery, materials, methods, and people (manpower). The machinery must work well, e.g. most important is the speaker system by which the order is transmitted and received, the bell and its operating system must work well, the menu sign must be readable and conveniently placed, the order computer/cash register must be working properly to give the total bill, and all the necessary equipment in the food preparation area must also be working properly. The materials used in order taking are few. However, the sign must be kept up-to-date with the latest prices and selection of menu items. The method currently being used is shown on the flowchart, and possible improvements are discussed in the next paragraph. The people who take the order must be trained to be courteous, friendly, accurate, and knowledgeable, or the systems quality will suffer.

Possible improvements to the system might include installation of a second window, so that the order is taken at the first window, money is collected there, and the pickup is made at the second window. A radio transmit/receive unit linking the customer at the sign to the employee wearing a headset could increase the ability of the employee to hear the order and to move around to assemble the order while the customer is driving through. Automatic order entry of standard selections might be built into the menu board with push buttons (similar to an automated teller machine in a drive-through banking operation). This would probably need to be coupled with personal assistance from employees for special orders via a speaker system.

8. The current process for fulfilling a room service request at the Luxmark hotel can be described as follows. After the tray is prepared at the room service station, the server proceeds to the room, knocks on the door, sets up the meal, has the customer sign the check, asks if anything else is needed, and then returns to the room service station.

a. Draw a flowchart that describes this process.

b. From the perspective of creating a high level of customer satisfaction from this experience, what improvements might you suggest to enhance this process? Think creatively!ANS. 8 a. Flowchart

8.b. A number of things could be done to enhance the service experience and make it more memorable for the guest. Broadly, these could be categorized as preparation, performance, and leave-taking.

Preparation steps

Tray layout liner, flower, salt/pepper, silverware, tray card

Food preparation salad, entree, condiments

Performance

Knock (exactly 3 times) and announce Room service.

Warm greeting and self-introduction (use names)

Permission to enter, enter, place tray, give a tour of the meal

Provide weather report and forecast

Request guest to sign check (use name)

Leave-taking

Offer a wake-up call

Ask if anything else is needed; if yes, radio for it

Warm thanks (use name)

Exit room, return to service area

9. Placewrite, Inc., an independent outplacement service, helps unemployed executives find jobs. One of the major activities of the service is preparing resumes. Three word processors work at the service typing resumes and cover letters. Together they handle about 120 individual clients. Turnaround time for typing is expected to be 24 hours. The word-processing operation begins with clients placing work in the assigned word processors bin. When the word processor picks up the work (in batches), it is logged in using a time clock stamp, and the work is typed and printed. After the batch is completed, the word processor returns the documents to the clients bins, logs in the time delivered, and picks up new work. A supervisor tries to balance the workload for the three word processors. Lately, many of the clients have been complaining about errors in their documentsmisspellings, missing lines, wrong formatting, and so on. The supervisor has told the word processors to be more careful, but the errors still persist.

a. Develop a cause-and-effect diagram that might clarify the source of errors.

b. What tools might the supervisor use to study ways to reduce the number of errors?

ANS. The C-E diagram, shown below, for this process analysis can be found in cleaner format in spreadsheet Prob 11-09 on the Premier website for this chapter.

EMPLOYEESPROCESSING METHOD

Experience

Number of clients per processor

Empowerment to contact client

Sequencing of work

Training on the equipmentError check method

Training on how to handle errors in copy

Instruction on resume writing

Format used by clients

Delivery of instructions to processor

CLIENT PROCEDURES

b. The supervisor might use flowcharts, checksheets and Pareto analysis to classify the types of defects and their frequencies. Then, training, crosschecking for errors, and work redesign might be done in order to remove those error causes. Once the process is under control, control charts might be used to hold the gains.

10.

A catalog order-filling process at Cats Catalog Company for personalized printed products for pet owners can be described as follows: Telephone orders are taken over a 12-hour period each day. Orders are collected from each person at the end of the day and checked for errors by the supervisor of the phone department, usually the following morning. The supervisor does not send each one-day batch of orders to the data processing department until after 1:00 p.m. In the next stepdata processingorders are invoiced in the one-day batches. Then they are printed and matched back to the original orders. At this point, if the order is from a new customer, it is sent to the person who did the customer verification and setup of new customer accounts. This process must be completed before the order can be invoiced. The next steporder verification and proofreadingoccurs after invoicing is completed. The orders, with invoices attached, are given to a person who verifies that all required information is present and correct to permit typesetting. If the verifier has any questions, they are checked by computer or by calling the customer. Finally, the completed orders are sent to the typesetting department of the print shop.

a. Develop a flowchart for this process.

b. Identify opportunities for improving the quality of service in this situation.

ANS. See flowchart, below, for the summary of the process at Cats Catalog Company. The most serious problem from the standpoint of customer service is the potential for a 12-hour delay before an order reaches the supervisor for error checking, and another 3-4 hours may be required before entry into the computer. Obviously too much checking and handling of the order occurred, and much of it was many hours after the customer and order information had originally been taken. Suggestions for improvement include: a) processing small batches of orders (perhaps within 1-2 hours, or less); b) building in error checking, perhaps through direct entry of telephone orders into the computer; c) processing information needed for customer verification and setup of new accounts at the time the order is taken; d) having the phone department supervisor simply audit or sample orders for errors; e) developing a computerized method of matching orders and invoices, so that manual verification is not required; generating an exceptions report after step (e), with proofreading required for printing information that cannot be computerized, if order verification and proofreading is a vital step.

11.A Six Sigma analyst in Riverside United Bank suspected that errors in counting and manually strapping cash into bundles were related to the number of weeks that employees had been employed on that job. The data found in the C11Data.xls file for Prob. 11-11 on the student Premier website for this chapter were gathered from the process. What do you conclude from your analysis? What do you recommend?

ANS. The scatter diagram shows that the employees accuracy in the strapping department of Riverside United Bank improves for approximately the first 25 weeks. After that, it basically levels off. The differences dont appear to be significant after about 30 weeks. (see spreadsheet Prob11-11.xls for details)

12.The times required for trainees in an electronics course at Elecktronica Tech to assemble a component used in a computer were measured. These are shown in the C11Data.xls file for Prob. 11-12 on the student Premier website for this chapter. Construct a histogram to graphically show the data. What recommendations for improvement would you give the course instructor, based on your findings?

ANS. The histogram indicates that the assembly time for the computer component in the electronics course at Elecktronica Tech is concentrated in the two periods from 9 up to 15 minutes and from 16 up to 20 minutes, which shows a bi-modal distribution. The highest frequency is for 17 minutes, representing the times of 20% of the students. Many students (approximately 50 percent) appear to be slower than the average (15.24 minutes) in the class. If the assembly quality is the same for the slower group as it is for the faster one, then the instructor should attempt to find the root cause, by observing the methods of both groups, as well as testing to see if there are any significant differences in abilities between the groups. Then the techniques of the two groups may be compared and the slower group members times may be reduced. (see Prob11-12.xls for details)

13.The times required to prepare standard-size packages for shipping at Pakman Shipping Company were measured. The packers were divided into two equal groups of 20 people, each, having similar experience in packing. These data are shown in the C11Data.xls file for Prob. 11-13 on the student Premier website for this chapter. Construct a scatter diagram for these data. What recommendations for improvement would you give the section leader, based on your findings?

ANS. The scatter diagram below (see spreadsheet Prob11-13) shows the packing time for a standard size package for Pakman Shipping is lowest for the first group of 20 packers, who average 13.85 minutes. In group 2, packers #22 and 37 are considerably slower than the faster group members, such as #30 and #31. Still, the overall packing time for a standard size package is higher for the second group of 20 packers, who average 18.45 minutes. This suggests that some workers, especially in group 1, are able to perform the task much faster than the norm (mean of 16.15). If the output quality is the same for the faster group, as well as the slower one, then the production coordinator should attempt to find the root cause, by observing the methods of both groups, as well as testing to see if there are any significant differences in abilities between the group members. If the methods used by the first group can be taught to the slower group members, this could increase productivity, reduce cost, and perhaps even improve quality, simultaneously.

14.The data found in the C11Data.xls file for Prob. 11-14 on the student Premier website for this chapter were gathered from a process used to make PrintGear, Inc.s plastic gears for a computer printer. The gears were designed to be 2.75 0.05 centimeters (cm) in diameter. Construct a histogram based on the data given. What can you observe about the shape of the distribution? What would you recommend to the production manager, based on your analysis?

ANS. The histogram on the graph below (see spreadsheet Prob11-14.xls for details) shows that, although the data are fairly uniformly distributed, 18 points are above the upper specification limit of 2.80 cm and 4 points are below the lower specification limit of 2.70 cm. It is likely that the process needs to be improved, with the first step being the removal of any special causes. Also, attention should be given to reducing variation in the process and centering it on the nominal dimension. A control chart would have to be constructed and/or a process capability study performed in order to get a fuller picture of the process.

15.Ace Printing Company realized that they were losing customers and orders due to various delays and errors. In order to get to the root cause of the problem, they decided to track problems that might be contributing to customer dissatisfaction. The list of the problems found in the C11Data.xls file for Prob. 11-15 on the student Premier website for this chapter shows their frequencies of occurrence over a six-month period. What technique might you use to graphically show the causes of customer dissatisfaction? What recommendations could you make to reduce errors and increase customer satisfaction?

ANS. It is obvious from the table and Pareto chart below that the first two categories, accounting for 64.3% of the errors, need improvement. See spreadsheet Prob. 11-15 for more detail

ACE PRINTING COMPANY

QUALITY ERRORS AND PERCENTAGES

PercentCumulative % Frequency

Setup delays35.00%35.00%245

No press time29.29%64.29%205

No paper11.43%75.71%80

Design delays10.00%85.71%70

Order info error5.57%91.29%39

Cust. chg, delays5.00%96.29%35

Lost order3.71%100.00%26

Total700

16.In an AcmeWidget, Inc. process, the production rate (parts/hour) was thought to affect the number of defectives found during a subsequent inspection. To test this theory, the production rate was varied and the numbers of defects were collected for the same batch sizes. The results can be found in the C11Data.xls file for Prob. 11-16 on the student Premier website for this chapter. Construct a scatter diagram for these data. What conclusions can you reach?

ANS. The scatter diagram (see spreadsheet Prob11-16.xls for details) for the AcmeWidget process, shows an interesting, and counter-intuitive result. As the production rate increases, the defect rate increases, then decreases. This could be because of the "learning curve" effect in that as operators become more skilled and familiar with the process and production runs are longer, the defect rate can be improved.

17.The number of defects found in 25 samples of 100 Gamma Candy Company lemon drops taken on a daily basis from a production line over a five-week period is given in the C11Data.xls file for Prob. 11-17 on the student Premier website for this chapter. Plot these data on a run chart, computing the average value (center line), but ignoring the control limits. Do you suspect that any special causes are present? Why?

ANS. The scatter diagram on the graph below (see spreadsheet Prob11-17.xls for details) shows that samples 11 and 12 were extremely distant from the average of 5.21. It is likely that an assignable cause was present. Other than that, the process appears to be stable, without excessive variations or trends up or down.

18.Analysis of customer complaints at DOT.COM Apparel Company revealed errors in five categories, such as billing, shipping, etc. Data can be found in the C11Data.xls file for Prob. 11-18 on the student Premier website for this chapter. Construct a Pareto diagram for these data. What conclusions can you reach?

ANS. From the Pareto diagram, below (and spreadsheet Prob11-18.xls), we can conclude that 54.2% of the problems are with electronic charge errors and another 25.1% are due to shipping errors, for a total in the top two categories of 79.3 %. These categories should be improved first.

DOT.COM APPAREL HOUSE

QUALITY ERRORS AND PERCENTAGES

PercentCumulative %Frequency

Electronic charge errors54.20%54.20%5420

Shipping errors25.10%79.30%2510

Billing errors7.95%87.25%795

Delivery errors6.95%94.20%695

Long delays5.80%100.00%580

Total10000

19.A pharmaceutical company that manufactures individual syringes is conducting a process capability study (see Chapter 13). The data shown in the C11Data.xls file for Prob. 11-19 on the student Premier website for this chapter represent the lengths of 35 consecutive samples. Plot these data on a run chart. Do the data appear to come from a stable system so that a process capability study may be conducted appropriately?

ANS. The data on the syringes, shown in the graph below (further details can be found in spreadsheet Prob11-19.xls) show a suspicious pattern that indicates that the process may be unstable. Ten values, from samples 20 to 29 are alternating above and below the average, indicating that some instability may be found in the system, if it is carefully investigated.

20.The Monterey Fiesta Mexican Restaurant is trying to determine whether sales of its popular Pan Con Mucho Sabor breadsticks are correlated with the sales of margaritas. It has data on sales of breadstick baskets and margaritas for 25 weeks, shown in the C11Data.xls file for Prob. 11-20 on the student Premier website for this chapter. Use the correlation utility, along with a scatter diagram, in Microsoft Excel to analyze these data. What do they indicate?

ANS. It can be seen on the correlation matrix (see Prob11-20.xls for details) that breadstick orders are highly correlated with numbers of margaritas. There is a 0.968 correlation coefficient. The scatter diagram also shows a consistent pattern, as well.

Correlation Matrix

WeekOrdersMargaritas

Week1

Orders0.0711021

Margaritas-0.062910.9680711

Answers to Projects, Etc.1. This project is designed to help the student to find how Six Sigma is viewed by various interested parties and reflected on their websites. Dont be surprised to see lack of agreement on concepts and definitions on the three sites.

2.This project will take significant time to develop, but can pay tremendous dividends in learning how to use the DMAIC process and some useful quality tools for problem solving and improvement. This would be a good term project for one or more students.

3. This project is designed to help the student to find which Six Sigma or lean techniques are used in businesses to improve their processes. Results will vary, but often are related to the quality focus in the firm. Most companies now track some output measures. Some Pareto charts and control charts may be found in many firms. Dont expect to see cause-an-effect diagrams, scatter diagrams, correlation and regression, or experimental design, except in the most sophisticated quality-minded organizations (for example, those with a Six Sigma program.)4. Results will vary. A flowchart for exams should be prepared, based on the steps that each student takes.

5. See the diagrams for a and b, below. The C-E diagram for c will be similar.

Answers to Case QuestionsCase - LT, Inc.

1. There are a number of steps that could be taken to improve the process. The Six Sigma team involved in this study recommended, and then carried out, the following improvement steps. They included:

Replaced the existing batch and queue system with a flow system. Customer orders were processed one at a time as they arrived. Individuals in each step were trained to do all activities in that step. Automated the billing system and encouraged customers to submit orders via the internet. Trained order processing employees to take data correctly, verify data for accuracy and completeness, and look for special terms. Created a system in which data was only entered once and transmitted electronically, with passwords to limit access.

Developed standard formats with built-in internal checks and fl ags to alert users about incomplete data, incorrect part numbers and faulty descriptions.

Trained shipping personnel to communicate with the billing department in a timely manner regarding partial shipments and returned goods.

Sent invoices only after receiving confirmation from shipping personnel that orders were sent.

Printed the name and phone number of the customers contact person, due dates and discounts on invoices to avoid runaround experienced by customers. Highlighting payment due dates and available discounts minimized customer calls and shrunk collection intervals.

Simplified the chaotic pricing structure and computerized it. Any deviations from the posted prices were immediately communicated to the necessary parties.

Suggested blanket agreements be negotiated and invoices sent on a monthly basis via the internet when possible. The free time that resulted would be used for training, to pursue value adding activities and to perform further kaizens.

2. Final actions development of metrics and next stepsThe Six Sigma team developed a set of relevant performance measurements to track the efficiency and effectiveness of the billing process. The metrics selected were: Total number of billing documents processed divided by the number processed per day.

Lead time to process customer order.

Cycle time to prepare a customer bill.

Average amount in accounts receivable divided by average number of sales.

Percentage of accounts received past due.

Sum of the dollar amount in accounts receivable, multiplied by the number of days since the sale, divided by the total number of days.

Percentage of erroneous bills.

Average time to correct an erroneous bill.

Number of billing complaints.

Average time to resolve billing complaints.

The team was fully aware of the powerful nature of working in cells and the success of just-in-time in manufacturing. For the next level of improvement, the Six Sigma team suggested that LT consolidate all activities into one cell manned by a team of personnel from sales (covering order taking, order preparation, order pricing and data processing), accounting (covering credit check, sales tax and billing) and shipping. The cells would be located in the shipping area, and cell personnel would take full responsibility for all activities from order taking through invoicing. Throughout the improvement project, the team communicated with LT management and received managements support.

Case Janson Medical Clinic

Analysis of the patient complaint data reveals that the three top complaint categories are wait for doctor, ease of appointment, and ease of phoning. All three of these are complicated to handle because of the nature of the business. It does appear that the telephone process is overly complex. The lack of empowerment of receptionists appears to be part of the problem. In addition there seems to be little telephone automation and no easy way of handling routine calls. This might be improved by providing routine phone options, such as ask about appointment date, ask about making an appointment, and billing questions. See Pareto charts, cause-effect diagram, and flowcharts, below. Also see spreadsheet C11JansonCase in the instructor materials for more details.

1.The data, for the Pareto Diagram, in order, from highest complaint level to lowest are:

Wait for doctor

13

Ease of appointment

12

Ease of phoning

10

Convenient hours

7

Courtesy of receptionist

7

Friendliness of phone receptionist 7

Responsive care via phone

5

Comfortable waiting

4

Physician listens

3

Respectful physician

2

Explanation of condition/treatment 2

Confidence in physicians ability 1

Time to register

1

Respect of nurses

0

Wait for doctor13

Ease of appointment12

Ease of phoning10

Convenient hours 7

Courtesy of receptionist 7

Friendliness of phone receptionist 5

Responsive care via phone 5

Comfortable waiting 4

Physician listens 3

Respectful physician 2

Explanation of condition/treatment 2

Confidence in physicians ability 1

Time to register 1

Respect of nurses 0

2. For the top three sources of patient dissatisfaction, the following C-E diagram shows some possible causes. Note that the answering method is closely related to the difficulty that patients experience in quickly and easily obtaining appointments. The C-E diagram, shown below, for this process analysis can be found in cleaner format in spreadsheet JansonCase.xls on the website for this chapter.

TELEPHONE ANSWERING METHODTELEPHONE EQUIPMENT

Lack of receptionist empowerment

Number of phone lines

Number of receptionists

Lack of telephone automation

Routine calls - same as emergencies

Inability to reach busy secretaries

Lack of refreshments in waiting area Excessive waiting time

Lengthy check-in process Magazines out of date or unappealing

No information on length of wait

No TV in waiting area

WAITING

3Below are flowcharts that address some of the problems being experienced with the current call answering and check-in process at the clinic.

Proposed Patient Registration Process

Answers to Case QuestionsReadilunch Restaurant

1. What Carol has, here, is a mess. She must sort out the demand pattern, the effects of time and day, if any, and the reasons for customer dissatisfaction. Note that the analysis presented here is not necessarily the only one for this complex set of data and issues*.

The average number of available tables is slightly less than 3.5. Although the scatter diagram on the graph below (see C11Readi1.xls on the instructor website for more details and graphs) shows that the utilization of tables is the highest from 11:30 - 12:15, the results, are somewhat difficult to sort out.

Scatter diagrams (in C11Read1.xls, not shown here) for Mon. -Tues. versus the one for Wed. - Fri. show some interesting differences. The Tuesday and Friday patterns are similar to each other in that tables appear to fill up earlier, and especially on Friday, seem to stay filled longer. These two days appear to differ from other days of the week and should be investigated further.

2. Analysis of the checksheet data on Complaints by Time may be done by looking at totals and constructing line graphs to try to discover patterns (see graph below and spreadsheet C11Readi2.xls on the instructor website). Nothing jumps out of these views of the data, although complaints about the long table wait peaks at 12:30. The total complaints remain high all the way from 12:30 until 2:00 p.m.

3. Pareto analyses of the complaints by category are much more revealing than the line graph shown above. This chart shows that long table waits and long lines are the two top causes. However these may both be related to inefficient service (cause 3).

Another Pareto diagram (in C11readi2.xls, not shown here) shows that there are more complaints on Monday and fewest on Wednesday, although the totals are not significantly different by day.4. Based on the Pareto analysis it appears that the long wait for tables is the most critical problem. Carol should investigate expanding the restaurant. If that is not feasible, she should at least consider the number of tables and their arrangement. She might also investigate a system for taking reservations during peak periods.

Since inefficient service (the third highest cause) may contribute to slow turnover of tables, she should consider ways to improve methods, including having wait people learn how to move customers along in a friendly way, and having bussers trained to quickly and efficiently clear tables.

To alleviate the problem of the long checkout line, Carol should also consider either adding another cash register, or perhaps placing the register at an exit door in such a way as to not conflict with customers who are entering.

If you come up with an alternate interpretation that you like better than this one, please forward it to Bill Lindsay ([email protected]). If we use it in the next edition, we will acknowledge your contribution.

Bonus CasesCase - Implementing Six Sigma at GE-Fanuc

1. Jack Welch borrowed the initial vision of applying the six sigma probability concept to operations at GE from Larry Bossidy, the CEO of Allied Signal Corporation, who had initially borrowed it from Motorola. Welchs vision was to deploy the methods and approach down to the operating levels where it could be applied to numerous processes. Thus, he specified that employees be trained in its science and methodology so that they would be able to improve efficiency and reduce variation in internal operations. This was done, more than 100,000 people were trained, and over $1 Billion has been saved since it was implemented.

2. Direct labor savings occur when a position can be eliminated from a department (for example, if a dryer operator is no longer needed because a dryer is removed). Labor cost avoidance savings are really indirect savings because only part of the workers duties are eliminated, thus freeing him/her to be used for other productive duties. If there are no other duties to be performed the worker must still be retained and paid for remaining tasks, even though not fully productive.

3.The calculation can be verified by taking 1/7703 X 1,000,000 = 129.8 or 130 dpmo.

4. The improvement started with a feeling that the step of testing the boards after running them through a high temperature oven was unnecessary. However, to verify that feeling required application of GEs systematic DMAIC problem-solving approach of defining, measuring, analyzing, improving, and controlling the process. After carefully defining the problem, Splauns team (measured) collected information on costs, and test failures at each point; analyzed what the impact of the testing was, improved the operation, and monitored (controlled) it to ensure that there were no unintended effects on quality. Future teams that hear of this successful project can be assured of coming up with useful results on their projects if they carefully follow the DMIAC steps, as Splauns team did.Case - National Furniture

The process used by National Furniture for special orders appears to have numerous points where orders can be misrouted or can go wrong. The C-E diagram and process map, shown below, for this process analysis can be found in cleaner format in spreadsheet NatFurnCase.xls on the instructors website for this chapter.

1.Below is the process map for the current process. 2.Below is the cause-effect diagram for why orders go wrong. Although it is not shown, or discussed in the case, it seems obvious that things could go wrong in the manager approval stage, or the front office for the store. The office manager or store manager probably related the information to the case writer!

3.The process map shows the steps in the process, while the cause-effect diagram shows where things can and do go wrong. The two can be used to improve the process. For example, the manager could check the form for completeness before giving the associate approval to process the order. The office manager could provide a clear label on the bin where the form is to be placed for processing, so that it is virtually mistakeproof. A Re-FAX stamp could be placed on orders that were resubmitted after more information was obtained. The office manager could help on follow-up for customer information by having a logbook that lists follow-ups to be done by order number and due dates for order delivery.

National Furniture Store

C-E Diagram for Special Order Errors

SALES ASSOCIATE ORDER PREPARATION

Lack of complete information from customer

Incorrect FAX bin

Lack of additional customer info to office

No request for office to re-FAX order

Lost or misplaced order

Wrong merchandise ordered

Store not notified when order is due there

REGIONAL OFFICE

ORDER PROCESSING

National Furniture Store

Current Special Order Process

No

Yes

Case - Welz Business Machines

For the Welz Business Machines case problem, a comprehensive analysis is required. The data and Pareto diagram, shown below, for this process analysis can be found in cleaner format in spreadsheet WelzCase.xls on the instructors website for this chapter.

Parts a. & b. See the cause and effect and Pareto diagrams, below.

c. The cause and effect diagram and the Pareto analysis help to determine where the problem of long telephone waiting may lie and point the way to some possible solutions. First, the Pareto diagram shows that the two major categories that account for most of the customer problems are no operator (operators short-staffed) and no receiver (receiving party not present). These reasons account for 73.1% of the customer complaints about long waits. The causes for these problems for phone service representatives seem to be that peak periods are not well staffed and there is no lunch break coverage. For the "no receiver" category, the sales representatives who are frequently out of the office seem to have no "back up" people who stay to receive calls.

Possible solutions are to bring in extra phone representatives for peak morning and afternoon periods, and either "stagger" lunch breaks or bring in extra representatives, then. The sales representatives, and/or their supervisors, should attempt to develop cross-training, so that everyone in the office is equally well-trained, sales representatives should be scheduled to be "on call" in the office at certain times, and communications should be set up in such a way that phone reps and sales reps work to coordinate customer service and communications, perhaps even giving the phone reps pager access to reach sales reps in the field. (See the welzcase.xls spreadsheet for further details.)

WELZ BUSINESS MACHINES

TELEPHONE WAITING TIME REASONS

AND PERCENTAGES

PercentCumulative %Frequency

No operator51.34%51.34%172

No call rcvr.21.79%73.13%73

No understnd.18.21%91.34%61

Customer5.67%97.01%19

Other2.99%100.00%10

Total335

Prepare tray

Take tray to room

Knock, saying Room service

Enter

Set up meal

Request signature on check

Return to service area

Ask if anything else is needed

Patient dissatisfaction

Nurse gets chart and calls patient

Papers embedded in chart form

Receptionist pages nurse

Signature taken, if needed