• Journal of the Korea Safety Management & Science
• /
• v.1 no.1
• /
• pp.123-134
• /
• 1999

There are several models for process quality assurance by quality system (ISO 9000), process capability analysis, acceptance control chart and so on. When a high level process capability has been achieved, it takes a long time to monitor the process shift, so it is sometimes necessary to develop a quicker monitoring system. To achieve a quicker quality assurance model for high-reliability process, this paper presents a model for process quality assurance when the fraction nonconforming is very small. We design an acceptance control chart based on variable quality characteristic and time-censored accelerated testing. The distribution of the characteristics is assumed to be normal or lognormal with a location parameter of the distribution that is a linear function of a stress. The design parameters are sample size, control limits and sample proportions allocated to low stress. These paramaters are obtained under minimization of the relative variance of the MLE of location parameter subject to APL and RPL constraints.

• Proceedings of the Safety Management and Science Conference
• /
• 1999.11a
• /
• pp.247-257
• /
• 1999

There are several models for process quality assurance by quality system(ISO 9000), process capability analysis, acceptance control chart and so on. When a high level process capability has been achieved, it takes a long time to monitor the process shift, so it is sometimes necessary to develop a quicker monitoring system. To achieve a quicker quality assurance model for high-reliability process, this paper presents a model for process quality assurance when the fraction nonconforming is very small. We design an acceptance control chart based on variable quality characteristic and time-censored accelerated testing. The distribution of the characteristics is assumed to be normal of lognormal with a location parameter of the distribution that is a linear function of a stress. The design parameters are sample size, control limits and sample proportions allocated to low stress. These parameters are obtained under minimization of the relative variance of the MLE of location parameter subject to APL and RPL constraints.

• Journal of the Korea Safety Management & Science
• /
• v.15 no.1
• /
• pp.293-301
• /
• 2013

The purpose of this study is to introduce the limit of previously used six sigma quality process evaluation metrics, $Z_{st}$ and $P_{pk}$, and a solution to overcome this drawback by using a metric based on performance evaluation of Z-factor quality innovation. Case analysis on projects from national six sigma contest from 2011 to 2012 is performed and literature review on new drug development HTS (High Throughput Screening) is used to propose innovative performance evaluation metrics. This research shows that experimental study on six sigma evaluation metric, $Z_{st}$ and $P_{pk}$, have no significance difference between industrial type (Manufacturing, Semi-Public Institute, Public Institute) and CTQ type (Product Technology Type CTQ, Process Technology Type CTQ). Following discovery characterize this quality improvement as fixed target type project. As newly developed moving target type of quality innovation performance metric Z-Factor is used for evaluating experimental study, hypothetical analysis suggests that $Z_{st}$ and $P_{pk}$ share different relationship or even show reciprocal relationship. Constraints of the study are relatively small sample size of only 37 projects from past 2 years and conflict on having interview and communication with six sigma quality practitioner for qualitative experimental study. Both moving target type six sigma innovation project and fixed target type improvement project or quality circle enables efficient ways for a better understanding and quality practitioner use by applying quality innovation performance metric. Downside of fixed target type quality performance evaluation metric, $Z_{st}$ and $P_{pk}$, is presented through experimental study. In contrast, advantage of this study is that high throughput requiring product technology, process technology and quantum leap typed innovation effect is evaluated based on precision and accuracy and Z-Factor that enables relative comparison between enterprises is proposed and implemented.

• Journal of Korean Society for Quality Management
• /
• v.30 no.2
• /
• pp.160-180
• /
• 2002

This is an exploratory research to examine the high-speed Internet access service's quality There are relatively scanty studies on telecommunication service quality such as the high-speed Internet access service. It has long been considered that service qualify are composed of process quality and outcome quality. Conducting an empirical research, we proposed that traditional outcome quality should be segmented with technical quality and outcome quality. Outcome quality is related to meeting consumer's needs to seek terminal value. In this paper, we explore to diagnose the well-known SERVQUAL's applicability to telecommunication industry and suggest some strategic and practical implications.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.1
• /
• pp.156-161
• /
• 2013

Recently, there has been a trend in the manufacturing process to focus on the durability of cable lug joint, especially in welding process due to the poor cable lug joint causes many troubles on products and workers during manufacturing process. Therefore development of high quality cable lug joint is important for successful manufacturing process and safety of worker. The Magnetic Pulse Forming(MPF) is one of efficient way to developed a high quality cable lug joint. In MPF, a high strain rate forming process, utilizes a high velocity oblique collision on the workpiece to be formed in required shape. The objective of this paper is to develop of high quality cable lug joint using electromagnetic force. To successfully accomplish this goal, section and electrical contact temperature of developed cable lug joint has been compared with various cable lug joint. Electrical contact temperature of developed cable lug joint by electromagnetic force is lower than manufactured cable lug joint by pressurer and hydraulic pressurer.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.33 no.4
• /
• pp.28-34
• /
• 2001

Korea traditional handmade paper, Hanji, has been known for more than thousand years for its high strength, high whiteness, high gloss, good ink reception and long lasting quality. Main component fiber of the Hanji is called 'Dak', which is the bast fiber of the Korea paper mulberry ($\textit{Broussonetia kazinoki}$). Dak has long fiber length, and high cellulose DP, if processed properly. The quality of Hanji is partly from the superior quality of Dak over wood fiber, and partly from the traditional papermaking process. The traditional papermaking process includes pulping, bleaching, refining, use of natural polymer, and sheet making process. Every traditional process has its special role. Comparisons between the modern papermaking technology and the traditional process were made in this study. The traditional process effectively protected cellulose DP in pulping and bleaching process, protected fiber length in refining process, and developed the high strength in the sheet forming process over the modern papermaking process.

• Journal of the Korean Society for Precision Engineering
• /
• v.11 no.2
• /
• pp.189-196
• /
• 1994

Quality assurance in the process of manufacturing high strengh bolt sets used in the frictional joints of structures in one of important concern to users as well as to manufactures. In case of occurrences of either defective or low-quality products, even if they are quite rare, some systematic means of localizing the cause-characteristics and matching to corresponding production process is necessary. Control chart of torque factor is the primary indicatir in finding defectiveness of the products. Use of correlation diagrams ofnhardness of the bolt set presents in part a way of screening the cause. Retest data of the bolt set provide additional ideas of localizing the cause, for which theoretical background is presented in this regard. A process-characteristics matrix relating the causes of low quality to the corresponding process of manufacturing, which is of prime importance for the feedback control of production, is also proposed. Finally general features of control to assure quality of the set is described.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.9
• /
• pp.128-133
• /
• 2020

This study was conducted to demonstrate the manufacturing process for producing high-quality solar salt. The design criteria of the manufacturing process, which was studied in a previous study, was applied to an actual manufacturing system to evaluate its performance. The design factors applied were the drying air temperature and the temperature of the washing water. They were 100℃ or less and 10℃ or less, respectively. Two standards were applied to the process performance evaluation. Standard (I) was the international food standard for solar salt, and standard (II) was the quality standard for high-quality solar salt production. The main quality evaluation items were the moisture content and salinity, and the color characteristics were also measured (p<0.05). The manufacturing process of solar salt consisted of five steps, and the quality change was measured for each step. The measured quality was appropriate to the standard (I) from the third-step process. In addition, the quality of the high-quality solar salt was suitable for the standard (II) from the fourth-step process. Therefore, the performance of the proposed solar salt production process met international standards. The improvements in the production of high-quality solar salt will improve international competitiveness in the future.

• KSTLE International Journal
• /
• v.3 no.1
• /
• pp.30-37
• /
• 2002

There have been significant improvements in base oil quality in order to satisfy recent market needs. In particular requirements of passenger car motor oils have been leading the trend. Now, high quality base oils such as VHVI base oils and PAOs are to be formulated in order to meet the tight volatility specifications. The severe hydrocracking, hydro-isomerized dewaxing and hydro-finishing process with noble-metal based catalysts (named UCO lube process) developed by SK corporation has been introduced as one of economic hydroprocessing routes to produce high quality VHVI base oils and food grade white mineral oils from fuels hydrocracker residue. Product quality of UCO lube process is similar to PAO in. general performances and therefore provides satisfactory performance far all straightforward applications in general lubricants. However, when applied to specialty lubricants like transformer oils, spray oils and coning oils, severely hydrocracked base oils are known to have various compatibility problems with gas or surfactants formulated in them. These problems are related to the difference in their composition; inherent high paraffin contents and lack of dissolving ability, Fortunately, it was found that excellent specialty lubricants could be made by carefully selecting and formulating adequate additives and/or aromatic compounds. Moreover, these specialties with high quality VHVI base oils ofter various advantages over conventional base oil based products.

• Corrosion Science and Technology
• /
• v.23 no.2
• /
• pp.131-138
• /
• 2024

This paper introduces Primetals Technologies' Through-Process Optimization (TPO) Services and Through-Process Quality Control (TPQC) System, which integrate domain knowledge, software, and automation expertise to assist steel producers in achieving operational excellence. TPQC collects high-resolution process and product data from the entire production route, providing visualizations and facilitating quality assurance. It also enables the application of artificial intelligence techniques to optimize processes, accelerate steel grade development, and enhance product quality. The main objective of TPO is to grow and digitize operational know-how, increase profitability, and better meet customer needs. The paper describes the contribution of these systems to achieving operational excellence, with a focus on quality assurance. Transparent and traceable production data is used for manual and automatic quality evaluation, resulting in product quality status and guiding the product disposition process. Deviation management is supported by rule-based and AI-based assistants, along with monitoring, alarming, and reporting functions ensuring early recognition of deviations. Embedded root cause proposals and their corrective and compensatory actions facilitate decision support to maintain product quality. Quality indicators and predictive quality models further enhance the efficiency of the quality assurance process. Utilizing the quality assurance software package, TPQC acts as a "one-truth" platform for product quality key players.