Thai Industrial Engineering Network Journal

Die Build-Up Generation and Improvement in a Case of Polypropylene Film Extrusion Process

2025-04-24T13:07:30+07:00

Die build-up is a persistent issue in plastic film extrusion, causing surface defects, product inconsistencies, and increased machine downtime. The use of Polymer Processing Aids (PPAs) is used in industry to reduce Die build-up. The aim of this study is to investigate the effect of PPA to reduce DBU during polypropylene (PP) cast film extrusion. In a first step, four different PP formulations with three manufacturing conditions are evaluated in order to get DBU. Then, in a second step, reduction of DBU is performed using the formulation with the highest DBU tendency with 1 phr and 3 phr PPA additives. Experimental results, observed over 30 minutes, indicate that the incorporation of 3 phr PPA significantly reduces DBU, improves film surface quality, and reduces the need for frequent equipment cleaning. The findings demonstrate the potential of PPA as a practical solution to enhance extrusion process stability and operational efficiency.

Biological Properties of White Portland Cement and the Effects of Nano-Silica on Its Mechanical Strength for Bone Substitute Applications

2025-04-23T14:21:24+07:00

White Portland Cement (WPC) is a ceramic material primarily composed of tricalcium silicate and dicalcium silicate, with a ferric oxide content of less than 0.5%. This composition makes it suitable for medical applications, particularly in orthopedic and dental surgery. This study focuses on developing composite material by incorporating nano-silica into WPC to enhance its mechanical and biological properties. The primary objective is to evaluate the biocompatibility and mechanical performance of the material through in vitro testing, including immersion in simulated body fluid (SBF) and cytotoxicity assessment on osteoblast cells. The results indicate that WPC exhibits both osteoinductive and osteoconductive properties, as evidenced by hydroxyapatite formation on its surface after 28 days of immersion in SBF. Cytotoxicity testing revealed that higher material concentrations reduced cell viability due to the release of calcium hydroxide (Ca(OH)₂), which may increase alkalinity beyond biocompatible levels. Regarding mechanical properties, the addition of nano-silica at 1%, 2%, and 3% significantly enhanced the material’s compressive strength. The highest compressive strength, 58.12 MPa, was observed at a 3% nano-silica concentration, attributed to structural reinforcement, reduced porosity, and increased formation of calcium silicate hydrate (C-S-H) gel, a key component in improving mechanical strength. These findings demonstrate that the development of a WPC-nano-silica composite enhances both mechanical and biological properties, highlighting its potential as a bone substitute material for medical applications.

Study of Calcium Phosphate Cement Derived from Chicken Eggshells for Injectable Bone Repair Applications

2025-04-23T10:33:00+07:00

This study presents the use of chicken eggshells as a key raw material in the synthesis of tetracalcium phosphate (TTCP), a major component of calcium phosphate cement (CPC). The research focuses on the application of CPC in an injectable form using 3D printing technology, aiming to simulate real-world medical applications. The results demonstrate that the powder-to-liquid (P/L) ratio significantly influences both the injectability and compressive strength of the CPC. P/L ratios of 1:0.46 and 1:0.48 g/mL achieved maximum compressive strengths of 4.63 and 5.58 MPa, respectively. Although these values are lower than the standard for trabecular bone, they indicate promising potential for further development. The synthesis of TTCP from chicken eggshells not only reduces production costs but also promotes sustainable use of natural resources. These findings highlight the opportunity to enhance the material's mechanical and biological properties, such as incorporating osteogenic stimulants, to improve its suitability for clinical applications, including bone repair and tissue regeneration. This research represents an important step forward in the development of biomedical materials that address both medical and environmental conservation needs in the future.

Enhancing the Durability of Springs for Car Seat Production

2025-04-23T19:43:07+07:00

The production of the A-model car seat began in 2020, and it must undergo an Endurance Test, which simulates repeated sitting and standing to evaluate its strength and lifespan. The seat must not sustain damage before the expected durability period at 500,000 cycles. However, in 2024, failures were detected in the zig-zag spring, a critical component of the seat. A thorough analysis identified multiple potential causes of the issue, and an in-depth investigation revealed that the primary cause was insufficient stress-relief annealing. This resulted in residual stress within the zig-zag spring, leading to premature failure during testing. To resolve this problem, the stress-relief annealing process was improved by increasing the heating duration from 15 minutes to 20 minutes at a temperature of 300 °C. This adjustment allowed the internal structure of the spring to release residual stress more effectively. Post-modification testing confirmed that the zig-zag spring successfully passed the endurance test without further damage.

Preventive maintenance design to reduce work order volume using FMEA: A Case Study A System Development Company

2025-04-25T10:45:59+07:00

The objective of this study is to lower the average rate of ticket jamming orders at BTS automatic doors that restrict passengers from leaving the station. These issues were evaluated and prioritized for response utilizing the principles of failure and impact analysis, as well as risk prioritization. Prior to the upgrade, it was discovered that the preventive maintenance plan did not identify the details of the inspection methods for the sensors and rollers, which were the primary causes of ticket jamming issues. In addition, there was no firm deadline for the job. This study implemented a weekly preventive maintenance plan that required maintenance people to work at four to five stations per day. Personnel were assigned to inspect the sensors using visual control methods, as well as inspect the rollers at the screws that hold the upper and lower rollers, in accordance with the defined work processes. The findings revealed that the average rate of ticket jamming orders at automatic doors at BTS stations was lowered from 2.49 to 0.48 orders per day, or 80.72% of the orders. The remaining ticket jamming orders at automatic doors were the result of software faults.

Reducing the Lead Time for Raw Material in the Store Department

2025-04-25T13:50:54+07:00

The case study company aims to reduce the amount of raw materials in stock to support the expansion of production capacity in 2026 due to limited production space. One method is to reduce the time to deliver raw materials to the production department. The main objective is to improve the raw material delivery process to be faster and to support the increase in production capacity. The researchers used the DMAIC Six Sigma principle as the main tool to analyze and solve problems that occur in the process. It was found that there were 11 types of raw materials, divided into 2 periods, from weighing to quality inspection in the system, with an average time of 2,605 minutes, and checking the test results in the database until the raw materials are produced, with an average time of 1,670 minutes. The total raw material delivery time is 4,275 minutes, resulting in having to wait for raw materials in the production process. From the analysis using the Prioritize Matrix tool and the fishbone chart, it was found that the main cause of the delay in raw material delivery is the lack of a standard cycle time for tearing the red part of the QMP document in the raw material warehouse department. Therefore, this research has improved the appropriate work process and arranged a standard cycle time for checking the quality of raw materials. After the improvement, the total material delivery time can be reduced by 1,472 minutes compared to the original working time (4275 minutes), or 34.5% of the time before the improvement. This results in increased efficiency in the material delivery process, reduced material preparation in the warehouse, reduced workload, and increased convenience for employees.

Optimizing Plant Layout Design and Selection via SLP and AHP: A Case Study of Namwa Community Enterprise, Chiang Rai Province

2026-01-19T11:03:44+07:00

This research aims to design and select an optimal plant layout for the Namwa Community Enterprise by integrating Systematic Layout Planning (SLP) with the Analytic Hierarchy Process (AHP). The primary focus is to eliminate production wastes and prevent cross-contamination in accordance with Good Manufacturing Practice (GMP) standards. The methodology commenced with a material flow and activity relationship analysis using an Activity Relationship Chart (ARC) to develop three alternative plant layouts. Subsequently, the AHP technique was employed to determine the importance weights of
the eight types of production waste. Expert evaluations indicated that the top three critical factors were:
1) Defects (22.60%), 2) Inventory (21.57%), and 3) Inappropriate Processing (17.49%). The results demonstrated that Layout Alternative 3 was the most suitable option, achieving the lowest weighted waste score of 1.00, compared to 1.30 and 1.48 for Alternatives 1 and 2, respectively. The selected layout completely eliminated both backtracking and cross-contamination risk points, representing a 100% reduction for both indicators. These findings contribute to enhancing production efficiency and
the competitive advantages of agricultural businesses in Chiang Rai province sustainably.

Reduction of Production Waste in High-Density Polyethylene (HDPE) Water Bottle Manufacturing by Recycling Plastic Scraps

2025-10-20T11:02:04+07:00

This study aimed to reduce waste in the production process of high-density polyethylene (HDPE) water bottles by reusing plastic scraps generated during manufacturing. In the existing production system, plastic waste resulted in an average material loss of more than 110,000 THB per month. To address this issue, a prototype plastic grinder was designed and developed to process HDPE scraps for reuse. The recycled plastic was then mixed with virgin HDPE grade A pellets at different ratios of 1:1, 2:1, and 1:2. The mixtures were subsequently processed using the blow molding technique to produce 20-liter water bottles. Tensile test specimens were prepared according to ASTM D638 Type IV and tested using a Universal Testing Machine (UTM). Five specimens were prepared for each mixing ratio, and each experiment was repeated five times. The results were analyzed using mean values and standard deviations.

The experimental results indicated that the mixing ratios of 1:1 and 2:1 produced tensile strength values within the standard range of HDPE materials (20–31 MPa). Among the tested ratios, the 1:1 ratio was identified as the most suitable, as it maintained the mechanical properties of the product without compromising material strength. The results demonstrate that incorporating recycled HDPE at proportions up to 50% can reduce production waste by approximately 50% and decrease raw material losses from about 110,000 THB to approximately 55,000 THB per month. These findings highlight the potential of recycling plastic scraps to improve resource efficiency and support sustainable plastic manufacturing in industrial applications.

Design and Development of a Semi-Automatic Robusta Coffee Bean Sorting Machine with Optimal Operating Conditions Determined by Response Surface Methodology

2026-04-30T15:27:12+07:00

Hin Chang Si Coffee community enterprise, Khon Kaen, Thailand faced a production bottleneck in coffee bean sorting (3.04 kg/h vs. target 100 kg/day). A semi-automatic Robusta coffee bean sorting machine was designed and developed comprising seven subsystems: electrical control, power transmission, bean storage, suction conveying, air-blowing impurity removal, a three-tier rotating sieve (apertures 7.5, 6.5, and 5.2 mm per TAS 5700-2561), and discharge. FEM verified structural integrity (σmax=33.73 MPa, FoS=18). Optimal conditions were determined via RSM-BBD with three factors: suction time X₁(10-20 s), air-blowing velocity X₂ (6.08-10.09 m/s), and drum speed X₃ (10-20 rpm). The quadratic model (R²=0.9989) revealed X₃ as dominant (β₃=-4.092, p<0.001), consistent with Residence Time theory; X₂ as secondary (β₂=-0.751, p<0.001); X₁ non-significant (p=1.000). The global optimum at X₁ =15 s, X₂=6.08 m/s and X₃=10 rpm yielded η=99.35%, throughput 38.49 kg/h (12.66× baseline, +1,166.12%), contamination ≤4%, conforming to TAS 5700-2561.

Classification and Management of Spare Parts Inventory: Case Study of Automotive Part Industry

2026-03-12T15:00:11+07:00

Spare parts inventory management is a complex and crucial task that can affect the cost and effectiveness of the production processes. The objective of this research is to propose a classification method and spare parts inventory management policy of an electric vehicle battery manufacturer in order to solve the problem of high inventory costs and shortages of spare parts when needed. This research focuses on integrating ABC analysis with VED analysis aided by Analytical Hierarchy Process (AHP) techniques in criticality assessment and grouping of spare parts according to their priority level. The research collected data on spare parts available in the database between 2021 and 2023, which totaled 1200 items, and selected 115 moving spare parts for study, equivalent to a total expenditure of 2,093,415 baht. AHP-aided VED analysis identified 3 criteria for evaluating the criticality of spare parts: 1) significance to production, 2) type of spare parts, and 3) ordering lead time. Using ABC-VED matrix, spare parts were classified into 3 classes according to their importance from highest to lowest. Classes 1, 2, and 3 accounted for 12.17, 50.44, and 37.39 percent of spare parts, representing 65.12, 26.77, and 8.11 percent of the total expenditure value, respectively. The research proposed the reorder point Max-Min method for managing spare parts inventory for class 1 and 2 whereas order as required policy should be used for class 3 spare parts. This research is beneficial to the case study company, which is an automotive parts manufacturer, by significantly improving the efficiency of parts inventory management and machine maintenance systems.

Problem-Solving Engineering Design for Reducing Time in the Process of Cutting Cassava Logs

2025-10-20T11:02:21+07:00

The production of cassava stem cuttings for replanting directly influences cultivation efficiency. Manual cutting processes present limitations in processing time, accuracy, and operational performance. This study aims to reduce processing time and enhance cutting efficiency by applying Engineering Design principles integrated with the ECRS concept to analyze and improve the workflow. The existing method was evaluated through a time study under actual operating conditions. Normal and standard times were determined using the Westinghouse System of Rating. A prototype cutting machine was then designed, developed, and experimentally tested. The results show that cutting time decreased from 332.20 seconds to 21.91 seconds per cycle, representing a 93.40% reduction. The findings confirm the effectiveness of engineering-based process improvement in enhancing productivity in agricultural production systems.

Application of an Artificial Intelligence Agent with RAG Technique to Reduce Diagnostic Time in Corrective Maintenance: A Case Study of an Air Conditioning Manufacturing Plant

2026-03-11T10:06:12+07:00

This research aims to enhance the efficiency of the corrective maintenance process in the air conditioning manufacturing industry, focusing on reducing waste in the diagnostic phase (Mean Time to Diagnose: MTTD). Based on a case study of the MC-01 machine, which experienced a maximum accumulated downtime of 362.81 hours per year, root cause analysis revealed that 36.58% of the total repair time delay was attributed to limitations in retrieving historical repair data from the Computerized Maintenance Management System (CMMS). The existing system lacked a standardized structure, making data difficult to reuse. This research developed an intelligent maintenance assistant system via the LINE Official Account application by integrating an Artificial Intelligence (AI) Agent with the Retrieval-Augmented Generation (RAG) technique and a Large Language Model (LLM) through the n8n automation system, acting as a mobile knowledge base for on-site technicians. The performance evaluation demonstrated that the system accurately supports decision-making and provides precise repair guidelines, resulting in a statistically significant reduction in MTTD by 46.77% at a 0.05 significance level. Furthermore, this system serves as a crucial tool that enables maintenance technicians of all levels to perform their tasks rapidly and efficiently in accordance with established standards.

Improving the Spare Parts Inventory Management: A Case Study of Sankampaengmotorgroup

2025-08-15T11:49:03+07:00

This research aims to reduce the time required for searching and retrieving spare parts by improving the inventory management system. The study was conducted as a case study at Sankampang Motorgroup, whose business involves construction contracting and the maintenance of electrical and mechanical equipment. As a result, a large volume of spare parts must be stocked to support operational continuity. However, the existing inventory management system lacked efficiency, leading to delays in searching for and issuing spare parts. In this study, industrial engineering and logistics tools were applied to improve warehouse operations. The root causes of the problems were first analyzed using a fishbone diagram, which revealed that process-related and material-related factors had the greatest impact on operational performance. Inventory data on spare parts withdrawals over a one-year period were then collected and analyzed using ABC analysis to classify items according to their level of importance. The results showed that 18 items were classified as Group A, 46 items as Group B, and 106 items as Group C. The ABC classification results were subsequently integrated with warehouse layout design and visual control techniques to optimize the arrangement and storage of materials according to their usage frequency and importance. The results indicated that the average time required to retrieve spare parts before improvement was 21.20 minutes, whereas after implementation it was reduced to 12.15 minutes. This represents a reduction of 9.45 minutes, or 44.06%. The findings demonstrate that the application of ABC analysis in combination with warehouse layout redesign and visual control can significantly reduce search time and enhance the operational efficiency of the spare parts warehouse.

Development of a Prototype for Container Forming from Local Natural

2026-01-26T13:59:33+07:00

This research focuses on the study and design of an innovative forming process for producing containers made from natural materials. The aim was to design containers made from teak and tropical almond leaves. The design and construction of a forming machine studied the forming of food containers and the bonding process. A prototype forming machine was designed and built using a pneumatics compression system, an aluminum mold (23 × 15 × 5 cm; W × L × H). Heat is supplied through flat-plate resistive heaters and Thermocouple control. Forming tests were conducted at temperatures of 120°c, 130°c, and 150°c to examine forming quality, bonding behavior, and shape accuracy. The results show that teak-leaf containers reached the best forming quality at 150°c using three leaves, requiring a forming time of 120 seconds. Indian-almond containers required six leaves and a forming time of 190 seconds. Under these conditions, the containers showed good strength, proper adhesion, and acceptable shape consistency. The prototype machine used an average of 1.716 kW of power, resulting in a monthly electricity cost of about 1,029.6 THB. Overall, the findings indicate that the prototype thermoforming machine is practical and has potential for use in community-based production or commercial applications.

Work Time Reduction through Maintenance Process Improvement of Split-Type Air Conditioners

2026-03-24T11:14:15+07:00

This research aims to achieve work time reduction through maintenance process improvement of split-type air conditioners. The study analyzed the cleaning and maintenance procedures of the evaporator coil using a Flow Process Chart to identify non-value-added activities, redundancies, and time-consuming tasks based on industrial engineering principles. The analytical results were then applied to improve the maintenance process through the implementation of a semi-automatic air conditioner cleaning machine.

The results showed that after the process improvement, the average operating time was reduced from 121 minutes and 5 seconds to 84 minutes and 25 seconds, representing a work time reduction of 36 minutes and 40 seconds. In addition, the improved process reduced unnecessary steps, enhanced operational convenience and safety, and lowered the workload of maintenance personnel. The findings indicate that maintenance process improvement is an effective approach for achieving significant work time reduction in split-type air conditioner maintenance tasks.

Development of a Real-Time Digital Inventory Management System for a Jewelry Manufacturing Company

2026-05-31T14:19:18+07:00

The case study jewelry manufacturing company experienced inventory management problems following organizational restructuring, which reduced the number of accounting staff and limited the ability to maintain complete inventory records. As a result, inventory data lacked accuracy and negatively affected purchasing planning efficiency. This research aimed to develop a real-time digital inventory management system for a jewelry manufacturing company by integrating Microsoft Excel, Google Sheets, and Google Data Studio with ABC Analysis to prioritize critical materials and improve inventory control efficiency. The developed system provided real-time dashboard visualization of inventory status, material withdrawal, and purchasing information, thereby reducing redundant tasks and improving data accessibility. The system was implemented and tested within the company for one month. The results showed that the average data recording time was reduced from 117.07 minutes to 14.04 minutes, representing an 88% reduction. In addition, the employee satisfaction evaluation indicated the highest level of satisfaction. The findings demonstrate that the application of low-cost digital tools integrated with ABC Analysis can significantly enhance inventory management efficiency and is particularly suitable for small and medium-sized enterprises.