Process Improvement Using Six Sigma Management Essay
You are tasked with setting up an improvement programme to deliver sustainable business benefit whilst developing a customer-focused continuous improvement culture. A Six Sigma approach is suggested as the basis for the programme. Review the literature and define the key elements of Six Sigma as presently practiced and critique this approach, suggesting how you might modify it (if required) in the circumstances described. Remember to justify any inclusions or omissions and to ground your work in the literature.
Critique a real Six Sigma project of your choosing. Discuss the approach, tools used, data selected and analysed, project management and handling of human factors.
Note that for the purposes of this question ‘statistical process control’ includes all the chart-based techniques covered on the course, including.
Choose any process within your organisation that is subject to statistical control using variable data. For this process:
Describe the quality characteristic(s) that are being controlled and describe the process through which these characteristics were defined.
Using the data collected over a suitable period, discuss the level of control of the process and independently calculate the capability of the process to achieve the quality characteristic(s) of the product or service.
Include in your answer all the data and calculations used to produce your findings.
Critically assess the method of control used and describe improvements, which could be applied to improve the control and subsequent capability of the process studied.
OR
Apply the techniques of SPC (using variable data) to any process within your organisation. In doing so you should address the following issues:
How was the quality characteristic selected and why is it appropriate?
What type of chart was selected to control the process? Explain the choice.
Was the data collection method appropriate?
Is the process capable of achieving the desired outcome?
What factors may contribute to the variability of the process? Categorise these causes into Special or Common.
How would you expect these factors to show up on the chart?
Question 4
Perform a Taguchi experiment (within a DMAIC improvement cycle) on the standard design of paper aeroplane (attached) to optimise a suitable quality characteristic. Analyse the data from the experiment and conclude on the design, predicting the results from your optimised design and confirm that your experiment has been successful. Comment on the results of your confirmation. In doing so;
Explain your choice of quality characteristic.
Define control and noise factors that you would include. Explain your choices.
Prepare an experimental design and carry it out, detailing how it was performed.
Indicate how you analysed the results. What conclusions did you draw? What would you do if the results you expected were not confirmed?
At all stages clearly explain what you did and your reasons for adopting the approach that you did.
Question 5
Lean and Six Sigma are two approaches to business improvement which have increasingly over the years gathered many followers. Traditionally the two approaches have been regarded as separate and, to some degree, antagonistic. Recently, attempts have been made to integrate the two approaches. By reviewing the literature on the origins of Lean and Six Sigma and the current theoretical and practical state of the art consider whether the two approaches are indeed compatible, and how successful the attempts to bring them together have been.
Question 6
Six Sigma ought to be a learning process. Consider the current literature on Six Sigma and your personal experience where relevant, and discuss how Six Sigma can make a contribution to Organizational Learning. Does the current literature on the implementation of Six Sigma support or inhibit it as a mechanism for Organizational Learning? You may focus your answer on either the improvement project level, or the initiative level; clearly state which you are considering in your answer.
Section B: Reflective writing
Write a short reflection on your learning from the PIUSS module. This should be no more than 500 words and should be submitted with the PMA.
Figure 1: Standard aero plane design
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Choose any process within your organisation that is subject to statistical control using variable data. For this process:
Describe the quality characteristic(s) that are being controlled and describe the process through which these characteristics were defined.
Using the data collected over a suitable period, discuss the level of control of the process and independently calculate the capability of the process to achieve the quality characteristic(s) of the product or service.
Include in your answer all the data and calculations used to produce your findings.
Critically assess the method of control used and describe improvements, which could be applied to improve the control and subsequent capability of the process studied.
Introduction
Statistical Process Control (SPC) has its roots back in 1920s. In May 1924 Walter A. Shewhart, who was working for Bell Telephone Laboratories, created the first control chart (CC) which is the most important element of SPC (Trietsch, 1999, p.1). This method was useful during the World War II and after that it was further developed by W.E Deming in Japan (Wetherill and Brown, 1991, p.1).
SPC is not simply a tool for monitoring a process and doing corrections when it is necessary (Kear, 1998, p.2). According to E. Deming (1986, p. 340) there are a lot of advantages when a process is under statistical control. Firstly its performance and its cost are predictable. Productivity is at maximum and all the measurements are more accurate. Also, a process can be improved only when is under statistical control (Deming 1994, p. 177).
This paper sets out to apply SPC theories in a process that is taking place in a Greek industry and investigate if that process is under control. This includes the choice of the Quality Characteristic (QC) and appropriate CC as well. In addition, the process capability will be calculated to investigate if the process meets the customer specifications. Additional objectives of that paper is to conduct a brief literature review of SPC regarding how is effectively implemented in order to gain the most positive results. For that reason, there will be an effort to specify all the necessary steps in order to integrate the SPC in a more philosophical approach than simple numbers and calculations of charts.
At the conclusion, there will be a review of the results and proposals for improvement of the current study and further projects as well. Lastly the emotional resistance will be discussed.
It is apparent that the paper is about a manufacturing process. Regarding the importance of statistical control in this type of processes Deming has stated (Deming as cited in Rosato, Rosato, and Rosato, 2000, p.1139):
“But a state of statistical control is not a natural state for a manufacturing process. It is instead an achievement, arrived at by elimination, one by one, by a determined effort, of special causes of excessive variation.”
Regarding the academic part of that paper there was almost now limitations. A lot of previous work have been done in this field. So it was easy to find references and develop ideas. As far as the practical part of that work there was a limitation due to the natural distance of the researcher with the rest of the team. All the communications took place through internet so is was difficult for the researcher to have direct control of the project.
Preparation for the application of SPC
Description of the process
Before describing the quality characteristic, it is useful to describe the product and define the process that is taking place for producing it. In that way the reader can have a more complete view regarding the paper’s effort.
Defining the process is a good base to start a quality control project (Juran and Godfey, 1999, sec.4.11). Mapping the flow of the process was very helpful to realize what was eligible to measurement through all the process and discern some quality characteristics of the product that were important to be controlled.
The industry is producing aerodynamic parts for the cars. Our survey will focus on the roof spoilers which is the major part of the organization’s product range. More precisely to a specific type of roof spoiler that is produced for a vital costumer of the organization. Bellow there is a demonstration of the process.
After 12 – 17 minutes the material is liquidized and the product is ditached from the mould. The mould is prepared for the next turn (5 minutes)
The mixed material is shed in the mould.
(The time and amount is depended from the size of the mould)
Moulds are warmed with water in more than 30 degrees
Polyurethane and isocyanate are mixed (analogy 1: 1.1)
Preparation Step Production Step
The product is immersed in diluter in order to get cleaned from the pasta used in the moulding process
The product is rubbed in order to deduct the flange that has been formed at the link of the two parts of the mould
The whole product is rubbed in pulveriser
The holes are covered with mastic
The product is painted with primary paint
The product is rubbed again so that little holes can be revealed
The mastic is rubbed for smoothing the surface
The product is ready to be packed and stored
The product is painted with primary paint
Figure 1. Production Process
Creation of the SPC team and success factors
People are always afraid of change. It is in human’s nature to be afraid of the new. There are a lot of factors who can cause resistance to change. One of the main ones is the argument (Lientz and Larssen, 2006, p. 157):
“What has been done in the past worked well”
While authors present more factors that lead resistance, there is a focus on this one because it is the most relevant with the current organization. People in that organization operate in the current way for more than twenty years. Their products are successful mainly at Greek market and abroad as well. So why they should learn something new?
For that reason there is a necessity to establish a framework that will facilitate the SPC implementation and will eliminate the resistance to change. In that way it will be more possibility to launch a successful project. There are four ingredients (Mason and Antony, 2000; Antony and Taner 2003) for the successful SPC application:
Management issues
Total company commitment
Creating a responsive environment for actions on the processes/ system
Necessary resources for training and education
Engineering skills
Understanding benefits
Gauge capability
Action taken and understanding of processes / systems
Reaction to process changes
Statistical skills
Statistical stability
Capability Correct use of charts
Histograms
Teamwork skills
Understanding benefits and rewards
Brainstorming
Cooperation from all levels
Table 1. Factors for successful implementation of SPC
There is the need to develop that factors so that we can have a successful project. It was decided that there must be launched two meetings before starting the project. The first one was between the general manager and the researcher. The reason why the first meeting was only with the general manager was that every program for improvement should start with the commitment of the top. Without this commitment everything is unstable during the change (Crosby, 1984, p.105). In that meeting the idea was introduced and the commitment from the top was achieved. The general manager agreed to provide all the possible necessary resources for the implementation of SPC. Through that the first factor was fulfilled. Lastly in that meeting there was decided who will participate in the team. The table bellow depicts the form of the team.
Member
Reason
General Manager
Overall inspection of the project. Provide the resources
The researcher
Coordinator of the project
R&D manager
Knowledge about statistics and SPC methods
Marketing and Sales manager
Link with the market. Knowledge about the process and the product (A lot of experience)
Operator of the production machine
Knowledge about the product and the process (A lot of experience)
Employee of the warehouse
Assistant in the project. He will measure the characteristic
Table 2. The SPC team
The team is sufficient to fulfill the second and third factor that were presented above. There were people with engineering skills that knew the process and the product. In addition there were two people who had the necessary statistical knowledge for this project.
The last to be achieved was the last factor. For that reason there was arranged a second meeting, between the members of the team. There the general manager introduced and aligned people towards the vision. This was crucial because there was created a base for achieving teamwork skills.
In addition there were launched some training sessions to everyone in the organizations that will be affected from the implementation of SPC. Despite the fact that there was an open discussion, the employees were free to express their disputes at the end of the sessions by putting notes in a box. The SPC team wanted to know what the disputes were and not argue with the employees.
All these had two aims. On one hand to develop the right skills, as described above, in order to implement successfully the SPC. On the other hand the researcher wanted to tackle the problems that Sheu and Krumwiede (1996) state as the common ones that small organizations encounter during the implementation of SPC.
Problem
Solution
Lack of funds for training
The commitment of the General Management was secured. He allowed three days seminars in the employees
Limited background in SPC
Due to the seminars the necessary background was developed
Unpleasant employees due to previous experiences
In this organization there was no one with previous experience in that subject. So we had to tackle the problem of resistance to the new. This was done through the seminars by letting people express their fears.
Table 3. Common problems of SPC implementation
Here it is interesting enough to refer that there was almost no serious dispute. The main argument, as it was expected to be, was that:
“We do it well why we must change it”
The team, after discussing the employees’ arguments, launched a new meeting where explained to the employees that this project is conducted so that the process can be improved. The main argument of the team was:
“We do not know if we do it well because until now we do not measure it”
After that meeting the employees agreed to take on the challenge and start the project.
Choosing the quality characteristic
This is a crucial step in SPC implementation. Deming (1982, p. 157) asks the managers if they know whether their organization’s processes, according to their QC, are under control. Quality of a product is determined by QC. Controlling them effectively, can give competitive advantage to a manufacturer. So it seems that the choice of the quality characteristics is of major importance (Shewhart, 1980, p. 38)
Juran (1999, sec.2.1) defines as quality on the one hand products with no defects on the other hand product characteristics that meet customers’ requirements. So the choice of the QC is not random. It is important that the controlled QC must address satisfaction to the costumers.
According to that concept it was decided to choose a QC that will be defined by the organization’s customers. Data from a previous costumer survey was used for that reason. In that survey, the organization had asked from some vital few customers to mention their expectations from the roof spoilers. The table bellow demonstrated the six most important costumers’ needs.
Ranking
Description of the need
1
Reliability of the product
2
Security (Aerodynamics)
3
Low price
4
Design
5
Easy installation to the car
6
Low consumption
Table 4. Customer Needs
The next step was to translate these needs into QC. For that reason it was used the House of Quality. This is a tool which is used to translate the customers’ needs (Voice of the costumer) into technical requirements (Voice of the engineer). Moreover, it helps in understanding the relationship between these two (Temponi, Yen and Tiao, 1999).
The needs were written down and the team created four measurable QC that are relevant to that needs. Then they added a factor in the needs regarding their importance. Then next step was to agree at the relevance between QC and costumers’ needs and chose the critical characteristic that will be controlled. This process and its results are depicted bellow on the House of Quality.
Relevance
Quality characteristics that are eligible to measurement
Importance Rating
Time of production
Weight of the product
Volume of the product
High
5
Medium
3
Low
1
Demanded Qualities
Reliability of the product
0,35
1
3
3
Security on the road (Aerodynamics)
0,2
5
3
Low Price
0,15
5
5
5
Design
0,15
1
Easy installation to the car
0,1
1
3
Low consumption
0,5
5
3
Sum
1
0,75
5,4
4,35
Rank
4
1
2
Table 5. House of Quality (Raharlo, Xie, Brombacher, 2010)
As it is apparent the Weight of the product will be the quality characteristic that will be measured. The manager of the organization asked from the team to provide him with a paper that will briefly demonstrate the relevance of that characteristic with the customers’ needs. The table bellow demonstrate the descriptions that were given.
Need
Description
Reliability of the product
Low weight probably means internal hole of the material. This can in combination of high temperature can produce defects of the product
Security (Aerodynamics)
Weight plays important role in stability and balance of the car, especially in high speed
Low price
More weight means more material (cost of material)
Less weight means less material which is disposed through the stage of processing (rubbing) – (work cost)
Design
No meaningful relevance
Easy installation to the car
Over-weight product can create problems in the installation especially if the installer has little experience.
Low consumption
Over-weight can increase fuel consumption especially in high speeds
Table 6. Relevance of QC and Customer Needs
It is crucial to mention that until now the team seems to enjoy the SPC project and take that as a positive experience. The resistance to change at this stage is almost zero.
SPC implementation
Deciding the charts and the data collection process
In the literature there have been developed a variety of SPC charts. For the purposes of that paper the Individual and Moving Range (X/MR) charts will be used. The reason that forced the team to chose these charts is mainly due to the nature of the production process.
According to Wheeler and Chambers (1990, p. 217) there are two types of data, periodical and regular. In the current process the data is periodical (20 minutes for each product to be prepared). The authors suggest that X/MR charts are the best choice for monitoring periodical data. This is for two reasons:
1.
In that type of data it is not effective to wait for a subgroup to be created. It needs a lot of time
2.
An increase of the subgroup’s size in a periodical data means that the subgroup needs more time to be created. This doesn’t guarantee homogeneity of the samples
Table 7. Attributes of Periodical Data
Chan, Tse and Yim (2003) based on some arguments regarding the low sensitivity of X/MR charts in respect to the usual Xbar charts conduct a theoretical survey and prove that individual charts have some advantages under certain conditions. Stapenhurst (2005, p. 270) argue that individual measurement the X-chart is much more sensitive that the Xbar- chart.
So from that we can conclude that despite the limitations that lead to use the X/MR chart, these charts are providing reliable information concerning the process’s statistical control.
As far as the data collection is concerned, reasonably assuming from the previous every product that will be produced it will be used for the construction of the charts. For that reason it was asked from the warehouse employ to measure the products before store them and collect the data in a sheet.
Juran and Godfrey (1999, p. 45.11) support that for a trial run of the chart the observations must be at least 20. For that research it was decided to take into consideration two days production. This results to 26 measurements, 13 each day.
Presentation of the data and construction of the control charts
The next step was to measure the QC. This took place at the end of the process (Figure 1) before the product was packed. The table bellow presents:
The weight of each product: (X)
The “positive” difference between two consecutive measurements:
(MR = │Xn – X n-1│)
The average of X : ( )
The average of MR: ()
Table of data
*All the results are in grammes
n
X (Day 1)
MR
n
X (Day 2)
1
1625
–
14
1633
2
1622
3
15
1613
3
1630
8
16
1623
4
1622
8
17
1630
5
1648
26
18
1638
6
1625
23
19
1629
7
1642
17
20
1633
8
1624
18
21
1632
9
1637
13
22
1648
10
1622
15
23
1639
11
1634
12
24
1642
12
1625
9
25
1626
13
1627
2
26
1615
Average
1630.15
Table 8. Quality Characteristic measurements and Moving Range
The next step is to calculate the control limits for both the X and the MR chart (Wheeler and Chambers 1990, p. 48). The calculations below present the equations that were used and the results as well.
Element
Type
Result
Upper Control Limit of X-chart
UCLx= Xbar+ (A2*MRbar)
1659.31
Lower Control Limit of X-chart
LCLx= Xbar- (A2*MRbar)
1601.00
Upper Control Limit of MR-chart
UCLMR = D4 * MRbar
35.81
Lower Control Limit of MR-chart
–
Table 9. Calculations for the limits
For these calculations we need two constants (May, G.S., Spanos, C.J., 2006, 440):
A2
2.660
D4
3.267
Table 10. Constants used for the calculations
Now all the necessary elements have been calculated. The next step is to construct the two charts which are depicted bellow.
Figure 2. X/MR chart for the process
Investigation of the results
Control Level
Now that the control charts have been created the next step is to realize if there are any special causes who produce variation. Western electric company has created some rules for “reading” a control chart. Wheeler and Chambers (1990, p. 96) propose the following four rules for investigating a chart.
Rule
Description
1
A lack of control is indicted whenever a single point falls outside the (three-sigma) control limits
2
A lack of control is indicated whenever at least two out of three successive values fall on the same side of, and more than two sigma units away from, the central line
3
A lack of control is indicated whenever at least four out of five successive valuesfall on the same side of, and more than one sigma unit away from, the central line
4
A lack of control is indicated whenever at least eight successive values fall on the same side of the central line.
Table 11. Western Electric Rules
While there are more than these four rules, like Western Electric Company’s patterns (Fournier, Rupin, Bigerelle, Najjar and Lost, 2006), Wheeler and Chambers argue that these four rules are enough. Also, they propose to start with the rule 1 and 4 and if there is the need for further investigation and more sensitivity implement the other two. Moreover they suggest that for investigating the MR chart, only the first rule should be used (Wheeler and Chambers, 1992, p. 217)
Someone can argue that more rules provide the ability to detect a special cause easier. This is far away from the truth. Deming (1994, p. 174) supports that there are two types of mistakes that can take place while someone interprets a control chart:
1.
To react to an outcome as if it came from special cause, when actually it came from common causes of variation
2.
To treat an outcome as if it came from common causes of variation, when actually it came from special cause
Table 12. Two types of mistakes
There is no case to eliminate both of these mistakes. This two mistake are interrelated and when someone tries to face the one of them at the same time increases the possibilities for the other to happen. This is what happening when someone adds more rules. The possibility of the first mistake to happen increases. On the other hand if someone deducts rules the possibility of the second mistake increases.
Under the concept that we cannot eliminate both of this mistakes, it can be assumed that the number of the rules that will be used are a decision making process. On the one hand there is the ability to reduce the number of rules and let more special causes treated as common. This will have as a result worst quality. On the other hand someone can increase the number of rules. Simultaneously, the possibility to have a false-alarm is increased. This will increase “tampering”. Tampering is when changes are taking place in a process that is under control. Despite the fact that there is the possibility for some of that changes to be right, the most of them is by chance and wrong. Also, tampering can have negative affection in performance. For example there is the cost of the change and psychological pressure to employees (Stapenhurst, 2005, p. 11).
Under that concept of thinking the team had to take a decision for the number of rules that will be used. It was decided to take into consideration the four rules that Wheeler and Chambers propose. The decisions are depicted in the table below.
Rules
Way of Using them
1 and 4
Strict rules that will definitely indicate a necessity for changes.
2 and 3
Supplementary rules that will indicate further investigation of the process control.
Table 13. Decision for the Control rules
So the first step is to investigate the variation in the Moving range chart. It is apparent that the MR chart is under statistical control because no point is out of the control limits.
As far as the X-chart is concerned in order to investigate its control level is necessary to re-produce the chart with depicting every sigma limit.
So we must calculate the value of 1-sigma (Standard Deviation):
6σ = UCLx – LCLx ó σ = ó σ ó σ = 9,72
Consequently we have:
Figure 3. X-chart with all Sigma levels depicted
It seems that the process is under control.
Rules 1 and 4:
No point is out of the Control Limits
No eight consecutive values are in the same side of the chart
Supplementary rules 2 and 3:
No two out of three successive values are on the same side and more than 2-sigma
No four out of five successive values are on the same side and more than 1 sigma
It is important to refer that the team was really excited with the results. All the members were satisfied that the process was under control.
Process capability
Up to that stage the chart has proved that the process is under statistical control. This means that the process’s performance is predictable for the immediate future (Deming, 1994, p. 174). But this is not enough. Process stability does not imply that the process is capable to meet the product specifications (Antony and Taner, 2003).
For that reason there have been developed various indexes that measure the process capability. These indexes can be calculated only for stable processes because performance of unstable processes is unpredictable. Wheeler and Chambers (1992, p. 130) state that “little can be said” for the capability of unstable processes.
These indexes have played an important role in the economic life of organizations. They provide evidence regarding the process ability to meet its production tolerance. Reasonably can be assumed that the tolerance can be set up by the customers of the organization. So in a way they measure the capability of the process to achieve its customers requirements (Wu, Pearn, Kotz, 2009).
While there have been developed a lot of indexes, the two that are the most widely used are the Cp and Cpk (Chang, Wu, 2008). The equations for that two indexes are:
Where, (USL, LSL) are the Total Tolerance or Specification width. The Cp index investigates the process’s variation in relevance with the width of the specification limits. Its drawback is that it doesn’t take into consideration the mean of the process but only the spread. This means that it is possible to have a good value of Cp and yet do not meet the customers’ requirements. To face this drawback the Cpk index was developed. This index takes into consideration both the process mean and the variation. The value of the Cp should be at least more than 1 in order to have capable process. (Oakland, 2008, p.257).
According to Oakland (2008, p. 264) a Cpk value more than one is not enough. The processes are unstable and a lot of factors can shift their performance. So there should be higher value in order to say that the process is capable to address the necessary results. His proposal of a good Cpk value is more than 1.67.
Lastly he states that if the difference between Cp and Cpk is zero this means that the process is on center (Oakland, 2008, p.263). This is depicted in the next equation (Stoumbos, 2002):
Cpk = (1 – k)*Cp
Where k is a figure used in Japan to express the distance between the average of the Process and the Nominal Value of the Specification limits. From this it can be assumed that an organizations should aim for a Cpk value equal to the Cp one.
In that project the team has decided to use these two indexes in order to measure the process’s capability. For that reason there was asked from a main customer to provide feedback regarding the tolerance limits that it perceives as qualitative.
The results where:
USL
1660
Nominal Value
1630
LSL
1600
Table 14. Customer’s Requirements (Tolerance Limits)
According to that Tolerance Limits and the Control Limits that were presented above we have the bellow results:
Cp
1.03
Cpk
1.02
Cpkl
1.03
Cpku
1.02
Table 15. Results of Process Capability Indexes
In order to Understand what this values tell us we should present the data in an Histogram.
Figure 4. Capability Analysis
If we take into consideration the theory that was developed above. We can say that the process is barely capable to meet the customers’ specifications. This is because their indexes (Cp and Cpk) are little higher than one. This may demonstrates capability but not stable capability. A positive result that emerged of this measurement is that the difference of Cp and Cpk is almost 0 (k = 0.009709) which shows that the process is on center.
Reasonably assumed the process is on target and in order to improve it, there must be a reduction of variation.
Review of the project
The last meeting of the team was to standardize and review the results and develop future plans regarding the process. Also it was an opportunity to share feelings and discuss this new experience.
It was interesting enough that people faced that as a challenge and not as a drudgery. When they were asked to declare why it was a positive experience for them they stated that:
Member
Reason
General Manager
Excited that the organization knows where to focus for improvement
The researcher
Excited that carried out this project
R&D manager
Ready for the next step. Implemented and developed leadership skills. Show a good opportunity for improvement
Marketing and Sales manager
He can sell by knowing that the product can barely meet the customers specification and that it will be further improved
Operator of the production machine
Learned more about “his process”. He is ready for the improvement phase.
Employee of the warehouse
Happy because he contributed to the organization’s project
Table 15. Team members’ feelings
For the current condition it was agreed that when there is production for the specific roof spoiler is taking place, a sheet for recording the weight measurement will be provided to the warehouse employee. Then they will be checked according to the diagram and the appropriate decisions will be taken.
As far as the future plans is concerned the team agreed that there is the need to pay more effort on that process. Despite the fact that it is barely capable it should be improved. This can be done by two ways and only when the process is under control (Deming, 1994, p.177):
Narrower variation
Move the average to the optimum
Both
In our example the process is stable and on target so it is crucial to investigate the sources of variation and reduce them as much as possible. Everyone was eager to participate in the next project for reducing the variation.
Discussion – Conclusion
Is SPC simple calculations of various indexes and constructions of charts? Is there the need for something more? Does employees’ psychology affect the results of an SPC project? How an organization can gain the most of the SPC implementation? This paper tries to give an answer in all that questions which seems to be of major importance not only for the academics but also for entrepreneurs.
This paper investigated the level control of a Greek industry’s process. This process was under control. In addition, while the process was capable to meet customers requirements it was proved that there is area for improvement.
Also is was proved that the SPC is not a simple process of calculations. There is the need of a more complete framework. First there must be commitment and creation of the team. In that level we saw that the problems which can occur from employees resistance to the new must be faced. The creation of a family and warm atmosphere, where every problem will be discussed is vital in that stage. In addition, Leaders should unite people launch meetings to educate, motivate and guide them, and let them express their feelings. After all that there must be a “customer focus” decision of the quality characteristic. The House of quality proved to be enough for that stage.
All the previous will allow the team to enter to the main part of the SPC. In that stage the reasonable choice of the chart is taking place. Inn that stage there should be a carefull decision of the control chart that will be used. Also, the number of rules used for measuring the control level is a decision that the organization should take very carefully. Lastly it is important to know if we meet costumer’s specifications so it is important to measure process capability.
Conclusions can be made by the review step as well. Despite the fact that the process, which was considered as “effective and efficient” before this project, proved to need improvements, employees wasn’t affected and still had positive psychology. This facilitated to the standardization of the SPC implementation achievements. Also, the team members were ready for the next project.
Despite the effort to produce a complete work there are some drawbacks in this approach. Firstly we used the X/MR chart. This decision was because the organization had an order of a certain product which provided us with enough measurements. But the main case is not that. Due to the small Greek economy the orders are small and the samples are not sufficient for plotting an X/MR chart. Further research should investigate the process by using charts for small runs ( ). Also, in that work variation of the measurement process wasn’t taken into consideration. Another improvement is to investigate the process capability with more indexes. Distance between researcher and the team was a problem but the technology reduced its affection. It would be a better choice the next project conducted with face to face communications.
Up to that stage we just prepared the team and measured the process. As it was proved there is the need for improvement. So further research can take place in that area. Probably the next step should be to launch a holistic six sigma project in order to improve this process.
SPC should not be treated as a concrete tool. This is because people are part of an SPC project and they affect its success. So in order to achieve the most of an SPC project the correct calculations are not enough. Managing people is crucial. The equations will provide better results only if people who choose and use them are motivated for being creative and aligned with the System’s aim.
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