Journal of Technical Education Science

Applying Six Sigma Method to Improve Product Quality of Automatic Water Valves

Khanh Linh Phan — 2026-08-28

This study aims to improve the quality of automatic water valve products by applying the Six Sigma methodology based on the DMAIC (Define – Measure – Analyze – Improve – Control) cycle. The study was conducted at company X, an electronics manufacturing services (EMS) provider specializing in the manufacturing, assembly, and processing of electronic devices and components. The current production status indicates a relatively high defect rate, mainly including functional defects and material-related defects, which directly affect product quality and performance. Prior to improvement, 179 defects were recorded out of 3,560 products, corresponding to a process capability level of 3.89 sigma. The DMAIC approach was applied to identify root causes and implement process improvement solutions, focusing on reducing major defects. The results show that the defect rate decreased from approximately 5.02% to below 4.00%. In addition, the defects per million opportunities (DPMO) were reduced to around 6,210, and the sigma level improved to 4.0.

Factors Influencing Vegan Cosmetics Purchase Intention: An Application of VBN Theory in Gen Z in Ho Chi Minh City

Ngoc-Phuong-Anh Phan — 2026-08-28

This research investigates the impact of three core value orientations - biospheric, altruistic, and egoistic - on the purchase intentions of Generation Z consumers toward vegan cosmetics in Ho Chi Minh City. Grounded in the Value-Belief-Norm (VBN) framework, the study explores the psychological mechanisms driving green consumption. By analyzing 344 valid survey responses utilizing Partial Least Squares Structural Equation Modeling (PLS-SEM), the results indicate that all three personal value dimensions show a positive correlation with the New Ecological Paradigm (NEP), with altruistic value exerting the strongest influence (β = 0.478; p < 0.05). Furthermore, the study examines the sequential mediating roles of awareness of consequences, ascription of responsibility, and personal norms. Within this structural model, personal norms emerge as the primary direct predictor of sustainable purchase intention (β = 0.767; p < 0.05). These findings provide empirical evidence for the theoretical framework of sustainable consumer behavior within the studied context and offer managerial implications for industry stakeholders in developing strategies to promote green consumption in the Vietnamese market.

Applying DMAIC to Improve Product Quality in a Fashion Company A

Thi Dieu Thao Nguyen — 2026-08-28

In an increasingly competitive environment, improving product quality is a key factor for manufacturing enterprises. This study aims to evaluate and improve product quality in a fashion company through the application of the DMAIC cycle, with the objective of reducing defect rates and enhancing process capability. The research is conducted based on the collection and analysis of actual data from the production department for product X, combined with quality control tools such as control charts, Pareto charts, and cause analysis to identify the main sources of defects. The results show that in the initial stage, the production process operated at a Sigma level of 3.181 with a relatively high defect density, in which the main defects included cup bulging, loss of decorative lace effect, and chiffon fabric scratches, accounting for the majority of total defects. Based on these findings, improvement solutions were proposed and implemented. After implementation, the Sigma level increased to 3.404, indicating the effectiveness of the solutions. The findings confirm that the application of DMAIC can enhance product quality and serve as a foundation for continuous improvement in the future.

Case Study Applying Six Sigma to Reduce Defects of DC Recessed LED Downlight

Chinh Le — 2026-08-28

This study applies the DMAIC process to improve the defect rate of DC recessed LED downlights at Company X. The author used quality management tools, including the fishbone diagram, the 5 Whys method, and FMEA analysis, to identify the root causes of major defects. The analysis is based on assessments of the R&D team leader, production team leader, and QA and QC staffs. Analysis results showed that no-light or flickering defects accounted for the highest proportion, 61.67% of the total defects. After analyzing root causes and implementing improvement solutions, such as standardizing welding techniques, adding voltage-testing stations, performing tensile testing, and improving wire-holding jigs, the no-light or flickering defect rate decreased from 9.87% to 3.00%. The Sigma level of the process increased from 3.6 to 4.0, resulting in a more stable and efficient operation. The study confirms the effectiveness of applying the DMAIC method in enhancing production capacity and competitiveness for businesses in the lighting equipment sector.

The Impact of TikTok Live Streaming on the Purchase Intention of Gen Z Consumers: An SOR Model Approach

Thi Hoa Mai Pham — 2026-08-28

This study applies the Stimulus–Organism–Response (SOR) model to examine the factors in TikTok livestream activities that influence the purchase intention of Generation Z consumers in Ho Chi Minh City. A total of 288 valid observations were obtained and analyzed using SmartPLS software to evaluate the measurement and structural equation through the PLS-SEM approach. The results indicate that several characteristics of livestream activities, including interactivity, visual appeal, seller professionalism, and social influence, positively contribute to increasing consumer trust. Among these factors, seller professionalism is identified as having the strongest impact. Consumer trust further exerts a significant influence on purchase intention on TikTok. In addition, product familiarity acts as a moderating variable that strengthens the relationship between trust and consumers’ purchase intention. Based on these findings, the study suggests that sellers should enhance professionalism in livestream activities and provide transparent and comprehensive product information in order to strengthen consumer trust and encourage purchase behavior among Generation Z consumers.

Improving the Reliability of the LED Bulb Measurement System

Nguyen Khoa Tran — 2026-08-28

This study addresses deviations in optical parameters and inconsistencies in the light-quality control process for LED Bulb products at Center X of Corporation Y. It aims to identify the root causes of measurement errors and develop a standardized measurement system to improve the accuracy and reliability of product data prior to shipment. To achieve this objective, the study employed Pareto analysis to determine the most critical defect categories and measurement system analysis to isolate major sources of variation within the existing process. The results indicated that errors related to luminous flux and correlated color temperature accounted for 83.23% of total nonconformities, highlighting these factors as the dominant quality issues. In addition, the initial overall variation of the measurement system was 35.51%, exceeding the acceptable threshold specified in the AIAG Measurement Systems Analysis (MSA) guidelines and indicating a serious limitation in measurement capability. To address this issue, Poka-Yoke error-proofing was introduced through fixed-position markers on the lamp-holder mounting rod, along with the standardization of operating procedures. Following implementation, the overall variation index of the measurement system was reduced to below 10%. These findings demonstrate that standardizing measurement capability can establish a reliable data foundation for product quality assurance and support research and development in sustainable lighting technologies.

The Impact of Key Opinion Consumer (KOC) Credibility Components on Gen Z's Purchase Intention on TikTok Shop in Ho Chi Minh City

Thi Kim Hong Nguyen — 2026-08-28

The study investigates the relationship between KOC source credibility and Gen Z’s purchase intention on TikTok Shop in Ho Chi Minh City, demonstrating that the dimensions of KOC credibility exert indirect effects on purchase intention through FOMO. Grounded in the Source Credibility Model, the research investigates four key dimensions, including expertise, trustworthiness, attractiveness, and similarity. A quantitative approach was employed, using 272 valid responses collected from Gen Z users (born between 1997 and 2012) who are currently living or studying in Ho Chi Minh City. The data were analyzed using SPSS and AMOS through techniques such as Cronbach’s Alpha, EFA, CFA, SEM and Bootstrap for mediation testing. The results indicate that all four dimensions of KOC credibility have positive and statistically significant effects on FOMO, with trustworthiness (β = 0.418) exerting the strongest influence. Furthermore, FOMO (β = 0.652) is found to have the most substantial impact on purchase intention and serves as a key mediating mechanism linking KOC credibility to Gen Z’s consumer behavior.

The Impact of AI Chatbots on the Purchase Intention of Gen Z in Ho Chi Minh City

Uyen Truong Thi Thao — 2026-08-28

As AI Chatbots are increasingly adopted in e-commerce, examining the impact of AI Chatbot characteristics on Gen Z consumers’ purchase intention in Ho Chi Minh City has become essential. This study investigates the factors influencing Gen Z’s purchase intention in Ho Chi Minh City by integrating the Stimulus–Organism–Response (SOR) model. The stimuli from AI Chatbots include information quality, service quality, perceived usefulness, interactivity, and anthropomorphism. Data were collected from 290 valid questionnaires and analyzed using the Partial Least Squares Structural Equation Modeling (PLS-SEM) approach. The results indicate that all five factors positively influence users’ attitudes toward AI Chatbots (p < 0.05), with anthropomorphism having the strongest effect (β = 0.251). Users’ attitudes play a mediating role and significantly enhance purchase intention (β = 0.625; p < 0.001). These findings highlight that Gen Z prefers chatbots with more human-like and socially engaging communication styles rather than mechanical responses. This study contributes to extending the SOR framework by identifying AI Chatbot characteristics as important stimuli and clarifying the mediating role of attitude in driving purchase intention. Furthermore, the study provides practical implications for businesses to optimize chatbot functionalities by developing natural communication styles and enhancing perceived value to encourage consumer purchasing behavior.

Measures for Self-Help Skills Education for 5–6-Year-Old Preschool Children Based on a Child-Centered Approach

Pham Thi My Nu — 2026-08-28

Educating 5–6-year-old preschool children in self-help skills based on a child-centered approach provides them with opportunities to experience, explore, and practice these skills through participation in diverse daily activities that match their individual needs and interests. This article aims to propose measures for self-help skills education for 5–6-year-old preschool children based on the child-centered approach, in line with children’s developmental characteristics and the current requirements for innovation in preschool education. This article employs information gathering and document analysis methods to identify the characteristics of 5–6-year-old preschool children, the child-centered approach, self-help skills of 5–6-year-old preschool children and self-help skills education for this age group. The article also proposes five measures for educating self-help skills through a child-centered approach and illustrates their application in preschool educational practice. The findings contribute to establishing a scientific foundation for designing and implementing self-help skills educational activities for 5–6-year-old preschool children based on the child-centered approach in preschool institutions.

Designing a Lesson Plan Oriented Toward Developing Problem-Solving Competency for Fourth-Grade Students in Mathematics Teaching

Hong Thuy Nguyen Thi — 2026-08-28

Developing problem-solving competency in teaching is an important requirement of the 2018 General Education Curriculum in Vietnam. This paper presents a study on designing and validating a lesson plan oriented toward developing problem-solving competency for fourth-grade students in Mathematics. The study employed a qualitative approach, combining theoretical analysis and teacher interviews. The study developed a framework of problem-solving competency indicators consisting of five components: understanding the problem, making a plan, carrying out the plan, checking the result, and adjusting the solution. Based on this framework, the paper illustrates a lesson plan in which learning activities are linked to competency indicators and observable evidence. The interview results show that teachers considered the indicator framework and lesson plan initially appropriate, clear, and feasible. They also suggested standardizing guiding questions, adding checkpoints for collecting evidence, assigning roles in group activities, and linking learning games with checking, explaining, and revising solutions. The study contributes to concretizing competency-based teaching in Grade 4 Mathematics. However, it has not measured the experimental impact of the lesson plan on students’ progress.