This study investigated the method of continuous improvement of small-medium company production processes through POSCO's QSS(Quick Six Sigma) activities. QSS is a field operation technique that encompasses the advantages of Six Sigma, TPS(Toyota Production System), TQM (Total Quality Management), and IE(Industrial Engineering). Through this, POSCO not only encourages activities centered on related small and medium-sized partners, etc., but is also expected to contribute to the continuous improvement of the company's own production process through QSS activities. In this study, rather than unconditionally carrying out activities according to the needs of large companies, the research is to help the continuous improvement of the actual production process of small and medium-sized enterprises by effectively applying and spreading QSS activities in consideration of the characteristics and environment of the company. For this purpose, empirical research is conducted on the process improvement activities and QSS activities of company Y, which has less than 100 assembly and production quality and inspection processes among SMEs. The changes in the production process improvement of SMEs through the application of the final QSS were investigated through empirical studies.
Six Sigma is a philosophy and systematic methodology for quality improvement. It encourages continuous quality improvement efforts to achieve the ideal goal of 6σ. Sigma(σ) is a statistic representing the standard deviation of the normal distribution, and 6σ level means a level where the tolerance of the specification is six times the standard deviation of the process distribution. In terms of the defective rate, the 6σ level achieves the 0.002 defectives per one million units. However, in the field, the 6σ level is used in the sense of achieving 3.4 defects per one million opportunities, which shows a large gap from the 6σ level in the statistical viewpoint. This is because field practitioners accept a 1.5σ shift of the mean of process when calculating the defective rate under sigma level. It said that the acceptance of 1.5σ shift of the mean is from experience, but there is no research or theoretical explanation to support it logically. Although it is a non-scientific explanation based on experience, considering that there has been no objection to the 1.5σ shift for a long time and it is rather accepted, it is judged that there is a reasonable basis for the 1.5σ shift. Therefore, this study tries to find a reasonable explanation through detective power of control chart via the run-rules to the 1.5σ shift empirically recognized by practitioners.
This study is an empirical study on the relationships among success factors of six sigma(support of top management, education and training, performance-based reward, customer and quality focused thought) on change management activity and business performance. In particular, mediating effect of change management activity on the relationship between success factors of six sigma and business performance is empirically analysed to find causes and impacts among these variables. The study results are as follows: First, there were positive relationships between critical success factors of six sigma(except support of top management) and change management activity. Second, there was also a positive relationship between change management activity and business performance. Third, there were also positive relationships between critical success factors of six sigma and business performance. Finally, change management activity was partial mediating effects on the relationship between critical success factors of six sigma(education and training, performance-based reward, customer and quality focused thought) and business performance. On the other hand, support of top management had no mediating effect on business performance.
The company's most important goal is to generate revenue. Managers want to lower prices, improve quality, and increase productivity. So many innovative activities have been developed. Businesses must perform management innovation. But many companies fail due to the difficulties of innovation. POSCO developed QSS with advantages such as TPS(Toyota Production System), TPM(Total Quality Management), Six Sigma, and IE(Industrial Engineering). The KOREA government spread QSS activities to enterprises. QSS activities are applied to manufacturing companies through training and activities, and basic capacities, maintenance capabilities, and improvement capacities are evaluated before and after the evaluation. An empirical study on BPR of companies through QSS innovation.
This study is an empirical study on the relationships among success factors of six sigma(support of top management, education and training, performance-based reward, customer and quality focused thought), job satisfaction, and quality performance. In particular, mediating effect of job satisfaction on the relationship between success factors of six sigma and quality performance is empirically analysed to find causes and impacts among these variables. A survey was conducted on the employees working in ‘H’ company which is applying six sigma at Ulsan City. The survey questionnaires were sent to 300 people and 216 of them were returned. Data obtained was analyzed with SPSS 18.0. The study results are as follows: First, there were positive relationships between critical success factors of six sigma(except support of top management) and job satisfaction. Second, there was also a positive relationship between job satisfaction and quality performance. Third, there were also positive relationships between critical success factors of six sigma(except support of top management) and quality performance. Finally, job satisfaction were full mediating effects on the relationship between critical success factors of six sigma(education and training, performance-based reward) and quality performance. Critical success factors of six sigma(customer and quality focused thought) had a partial mediating effect on quality performance. On the other hand, support of top management had no mediating effect on quality performance.
This research discusses the characteristics and the implementation strategies for two types of quality metrics to analyze innovation effects in six sigma projects: fixed specification type and moving specification type. Zst, Ppk are quality metrics of fixed specification type that are influenced by predetermined specification. In contrast, the quality metrics of moving specification type such as Strictly Standardized Mean Difference(SSMD), Z-Score, F-Statistic and t-Statistic are independent from predetermined specification. Zst sigma level obtains defective rates of Parts Per Million(PPM) and Defects Per Million Opportunities(DPMO). However, the defective rates between different industrial sectors are incomparable due to their own technological inherence. In order to explore relative method to compare defective rates between different industrial sectors, the ratio of specification and natural tolerance called, Ppk, is used. The drawback of this Ppk metric is that it is highly dependent on the specification. The metrics of F-Statistic and t-Statistic identify innovation effect by comparing before-and-after of accuracy and precision. These statistics are not affected by specification, but affected by type of statistical distribution models and sample size. Hence, statistical significance determined by above two statistics cannot give a same conclusion as practical significance. In conclusion, SSMD and Z-Score are the best quality metrics that are uninfluenced by fixed specification, theoretical distribution model and arbitrary sample size. Those metrics also identify the innovation effects for
before-and-after of accuracy and precision. It is beneficial to use SSMD and Z-Score methods along with popular methods of Zst sigma level and Ppk that are commonly employed in six sigma projects. The case studies from national six sigma contest from 2011 to 2012 are proposed and analyzed to provide the guidelines for the usage of quality metrics for quality practitioners.
Because of user's apathy and carelessness, it is difficult to keep the public places (such as school practical rooms) clean. In this study, we presented a six sigma project to improve the level of cleanliness of a university laboratory. We applied the DMAIC (define, measure, analyze, improve, and control) procedure which is the general methodology of the six sigma project. In the process of DMAIC, we listened to the VOC, quantified the level of cleanliness as the level of sigma, and performed various activities to improve user's consciousness level. As a result of the project execution, cleanliness satisfaction has been increased about more than three times. It is expected that results of the proposed case study can be applied to other public places. Also, this study showed the academy campus can be used as a good place for the practical six sigma education.
This paper aims to propose a new steps of hypothesis testing using analysis process and improvement process in the six sigma DMAIC. The six sigma implementation models proposed in this paper consist of six steps. The first step is to establish a research hypothesis by specification directionality and FBP(Falsibility By Popper). The second step is to translate the research hypothesis such as RHAT(Research Hypothesis Absent Type) and RHPT(Research Hypothesis Present Type) into statistical hypothesis such as H0(Null Hypothesis) and H1(Alternative Hypothesis). The third step is to implement statistical hypothesis testing by PBC(Proof By Contradiction) and proper sample size. The fourth step is to interpret the result of statistical hypothesis test. The fifth step is to establish the best conditions of product and process conditions by experimental optimization and interval estimation. The sixth step is to draw a conclusion by considering practical significance and statistical significance. Important for both quality practitioners and academicians, case analysis on six sigma projects with implementation guidelines are provided.
To maximize the operational efficiency of production and operations systems, Six Sigma and Lean Production System have been widely used. The main focus of Six Sigma is reducing variations, whereas that of Lean Production System is eliminating losses. To take advantage of the two approaches Six Sigma and Lean Production System was integrated into Lean Six Sigma, and the integrated approach has been used in recent years. In the implementation of Lean Six Sigma, the problems under consideration have often physical or technical contradictions which are difficult to be solved by conventional methods. To solve such contradictions TRIZ is useful in many cases. In this thesis, it is considered that how TRIZ can be applied to Lean Six Sigma. An integrated road-map of Lean Six Sigma and TRIZ is suggested and some cases are reviewed.
The case company has driven the six sigma innovation programme companywide for the last seven years without any stop in spite of the CEO change. There was neither any benchmark nor the sufficient number of internal experts during the initial stage of driv
This paper presents a six sigma application case study for an automobile PCSV manufacturing process using rolled throughput yield improvement activity. Hidden factor and first yield concept is introduced and DMAIC procedure is implemented to maximize the first pass yield. The result of the six sigma project amounts to the reduction of failure cost of 0.1 billion won per year in the PCSV manufacturing process. This paper can benefit six sigma practitioners in some ways.
In this study, we took the census of the project satisfaction level of the employees who have participated in Six Sigma projects. We divided and measured the project satisfaction by the steps of performing the project (team building, execution, ownership
The purpose of the study was to apply and to expand the six sigma to reduce waiting times for computed tomography (CT) examination which manipulated by the department of radiology. It was preceded by DMAIC (Define, Measure, Analyze, Improve, and Control). In the stage of definition, it wereselected for total 5 critical to quality (CTQ), which were the kindness, the waiting time, the examination explanation, the waiting day and the waiting stand environment, that increased the reserved time of CT examination. In the stage of measurement, the number of examinations and of reservation waiting days performed and resulted in final CTQ(Y) which measured each 1.68 and 1.85 sigma. In the stage of analysis, the examination concentrated on morning time, non-scheduled examination of the day, the delayed time of booking, frequent telephone contacting and equipment malfunction were determined as variable key causes. In the stage of improvement, it were performed with expansion of the examination in the morning time, integration of laboratories that used to in each steps, developing the ability of simultaneous booking schedule for the multiple examinations, developing program of examination request, and the customer management team operations. For the control, the number of examinations and reserved waiting days were measured each 3.14 and 1.13 sigma.
Recently, China's economic development has been accelerated by its WTO entry and hosting Bejing Summer Olympic, so on. Many Chinese companies are facing more global competition, while they are growing faster. Therefore, in order to win the battle in the global market, they should improve their efficiency by implementing various management innovation tools such as 6 sigma. 6 sigma is a well-known methodology to improving management efficiency and has been implemented by many global companies. While a large body of research in the field of 6 sigma has been conducted and known in many countries such as USA, Japan, EU, and Korea, Chinese research papers on 6 sigma are still unknown. In this paper, we search, review and summarize the Chinese research papers. Based on this review, we propose the right direction of the 6 sigma research in China.
The paper proposes the misuse types of statistical quality tools according to the kind of data and the number of population in DMAIC process of six sigma. The result presented in this paper can be extended to the QC story 15 steps of QC circle. The study also provides the improvement methods about control chart, measurement system analysis, statistical difference, and practical equivalence.
This paper presents a six sigma project for improving customer satisfaction of a franchise store. The project follows a disciplined process of five macro phase : define, measure, analyze, improve, and control(DMAIC). Due to the limitation of existing methodologies, numerous difficulties arise during the six sigma application to transactional processes. This paper expected to be helpful to service industry in which is very difficult to measure and implement.
Six Sigma is widely recognized as a process improvement methodology. In these days, many organizations today are considering how to choose six sigma project. Th is study is to provide six sigma project selection criteria by comparing public corporate with