Kasem Bundit Engineering Journal

การปรับปรุงกระบวนการผลิตชิ้นส่วน U-RIB ANGLE: กรณีศึกษาบริษัทผลิตอุปกรณ์เครื่องมือทางการเกษตร A

Tue, 28 Apr 2026 00:00:00 +0700

The research aims to improve the production process of U-Rib angle parts of hallow discs by applied the principles of work-study, Cause and Effect Diagram in data collection, and problem analysis. From the study production process of U-Rib angle parts, the steps are: 1) cutting steel sheets and forming them initially with laser cutting, 2) bending them into a U shape, 3) drafting the workpiece design using a fixture layout, 4) cutting excess materials according to the layout using the fixture layout, and 5) welding assembly them with other parts. From these production steps, there are excessive processes, namely the workpiece layout with the fixture layout and cutting excess materials, which results from the incorrect size by the laser cutting process along with low-quality bending. Addressing these issues, the ECRS principle was applied to eliminate unnecessary work steps. This was achieved by first utilizing sheet metal drawing principles to determine the correct blank size prior to laser cutting, and subsequently by improving the bending process through the design and implementation of a Rolla V Die. As a result of improving the production process, the number of production steps was reduced from 13 steps to 8 steps, and the production time decreased from 7 minutes 11 seconds to 5 minutes 35 seconds, a reduction of 1 minute 36 seconds. This represents a 22.25% reduction in production process time and a reduction in scrap materials loss by 0.23 kg/piece or 5.64 percent loss reduction, Costing around 1,380 bath/month at a capacity of 200 pieces/month.

การอบแห้งขมิ้นชัน (Curcuma longa L.) ด้วยเทคนิคไมโครเวฟ-สุญญากาศ: ผลของกำลังไมโครเวฟและความดันที่มีต่อจลนพลศาสตร์การอบแห้ง

ณัฐภัค อิ่มเอิบ, จิรวัฒน์ สิตรานนท์, กิตติศักดิ์ วิธินันทกิตต์ — Tue, 28 Apr 2026 00:00:00 +0700

This research studies the drying of turmeric (Curcuma longa L.) using microwave-vacuum drying techniques. Key aspects investigated include drying kinetics, drying rate, effective moisture diffusion coefficient, specific energy consumption, color change, and empirical modeling. Drying processes were performed using 800 W microwave power at atmospheric pressure, and at microwave power of 600, 700, and 800 W at absolute pressures is 20 and 30 kPa. Experimental results showed that increasing microwave power and decreasing absolute pressure resulted in higher drying rates and effective moisture diffusion coefficients with reduced specific energy consumption. Decreasing absolute pressure also resulted in lower overall color difference compared to drying under atmospheric pressure. Furthermore, the Mildilli empirical model provided the best prediction for turmeric drying, exhibiting the highest R2 value (0.99995) and the lowest RMSE value (0.00323).

ปัจจัยที่กำหนดการตัดสินใจเลือกใช้แรงงานต่างด้าวของผู้รับเหมาในงานก่อสร้างภาคเอกชน: กรณีศึกษาแรงงานพม่าและกัมพูชา

เทวกุล จันท์ขามป้อม, วรรธนะ ประภาภรณ์ — Tue, 28 Apr 2026 00:00:00 +0700

This study analyzes the hierarchical structure of factors influencing contractors’ decisions to employ migrant workers in Thailand’s private construction sector, with particular emphasis on Myanmar and Cambodian labor. A quantitative research approach was employed using a questionnaire survey of 216 engineers, contractors, and site supervisors involved in private construction projects in Bangkok and its metropolitan areas. The data were analyzed using second-order confirmatory factor analysis (CFA) in AMOS. The results indicate that the proposed decision-making model fits the empirical data well and that contractors’ decisions can be explained by five key dimensions: employment, laws, labor costs, labor characteristics, and economic conditions. Employment-related factors exert the most decisive influence, followed by legal, cost, labor characteristic, and economic factors. The findings suggest that contractors’ decisions are not driven solely by labor costs but reflect a multidimensional decision-making process that integrates labor flexibility, legal compliance, and project efficiency. This study provides empirical evidence on the structural roles of employment and legal factors and offers practical insights for migrant labor management in Thailand’s private construction sector.

การพัฒนาอุปกรณ์จับยึดเพื่อลดเวลาในกระบวนการกัดยางกันกระแทกคัปปลิ้ง

ณัฐภัทร กาญจนเรืองรอง, ศรินยา ประทีปชนะชัย — Tue, 28 Apr 2026 00:00:00 +0700

This research aims to develop a jig and fixture to shorten machine setup time in the CNC milling process of rubber coupling components made from polytetrafluoroethylene (PTFE). Due to the high slipperiness and flexibility of the material, conventional manual clamping and positioning resulted in long setup time and high variability. The study applied work and time study techniques, including left–right hand chart analysis, direct time measurement, Westinghouse performance rating, and standard time calculation. The ECRS principle was employed to identify non–value-added activities, particularly in tool setup and workpiece reference positioning. Based on the analysis, a new jig and fixture made from MC Nylon was designed to provide a fixed reference position and minimize reliance on operator skill. After improvement, the number of production steps was reduced from 10 to 9, and the total cycle time declined from 1,151.05 seconds to 956.43 seconds, representing a 16.9% improvement. The non–value-added time of the left hand dropped by 16.3%, while the CNC machining time remained unchanged. The research results indicate that the developed workpiece fixture can effectively shorten machine setup time, improve the consistency of workpiece positioning, and mitigate variability caused by human operations. As a result, the production process becomes more continuous and operates with higher efficiency.

THERMAL PERFORMANCE OF A PHOTOVOLTAIC-THERMAL SOLAR DRYER INTEGRATED WITH HIGH-POROSITY STEEL MESH

Tue, 28 Apr 2026 00:00:00 +0700

The growing global demand for sustainable, cost-effective drying technologies has driven significant advancements in solar drying systems. This study experimentally evaluated the performance of a solar dryer integrated with porous materials for drying kaffir lime leaves under tropical climatic conditions in Thailand to enhance thermal efficiency and drying effectiveness. The dryer incorporated a 150 Watt photovoltaic-thermal (PVT) panel, a double-pass solar collector, and porous materials with a porosity of 0.97 onto the absorber plate. Experiments were conducted at air velocities of 0.07, 0.09, and 0.10 m/s to investigate drying kinetics, including moisture ratio (MR), drying rate (DR), and specific energy consumption (SEC). The results revealed that moisture removal occurred primarily during the falling-rate period, governed by internal diffusion. The integration of porous materials enhanced drying performance, with DR improving by approximately 45-50% and SEC decreasing by 30-33% compared to the case without porous materials. Statistical analyses using two-way ANOVA confirmed significant effects of air velocity (p < 0.05) and porous materials (p < 0.01), with porous materials identified as the dominant factor. Overall, the solar dryer incorporated with porous materials demonstrated faster drying, greater thermal stability, and improved energy efficiency.

อิทธิพลของความแข็งแรงเดิมของมวลรวมคอนกรีตรีไซเคิล และระดับการทดแทนต่อกำลังอัด การต้านทานการขัดสี และการแทรกซึมคลอไรด์ของคอนกรีต

ทวีศักดิ์ ทองขวัญ, นันทชัย ชูศิลป์, จุฑามาศ ลักษณะกิจ, เปรมณัช ชุมพร้อม — Tue, 28 Apr 2026 00:00:00 +0700

This study examines the effect of the original strength of RCA recycled concrete aggregates and the level of coarse aggregate substitution to the mechanical properties and durability of concrete. Using RCA from 2 sources: 1RCA with a compressive strength of 20-25 N/mm² and 2RCA with compressive strength of 40-45 N/mm². Concrete was evaluated compressive strength BS EN 12390, abrasion resistance ASTM C 944 and chloride ion penetration ASTM C 1202. The test results showed that the mortar texture adhering to the RCA aggregate surface caused high porosity and water absorption. The compressive strength of 2RCA concrete provides a compressive strength value higher than 1RCA by 1-7%, indicating the influence of the quality of the recycled concrete at the source. Under a constant water-cement ratio. Compression tends to increase as RCA substitution levels increase. Abrasion resistance is better when RCA is used. Concrete based on 2RCA provides a loss value due to abrasion that is 5-27% lower than 1RCA. Chloride ion penetration resistance performs better according to RCA substitution levels and is in the moderate to low range. All studies show that the performance of RCA-based concrete is determined by the quality of the source concrete and the level of substitution. At least 50% of the concrete aggregates can be recycled without adversely affecting compressive strength, abrasion resistance, and chloride ion penetration.

REPRESENTATIVE-DAY DISCRETE-EVENT SIMULATION TO REDUCE OVERTIME IN OUTBOUND WAREHOUSE DOCKING

Pachira Na nan, Thammawit Prasert, Peerapong Pakawanich — Tue, 28 Apr 2026 00:00:00 +0700

Overtime in outbound warehouse docking operations is a persistent logistics challenge, yet existing studies rarely address realistic labor calendars, zoning constraints, heterogeneous truck-type processes, or extreme congestion days. This study develops a data-driven, minute-resolution discrete-event simulation (DES) in Python to evaluate five dispatching and bay-sharing policies (S0–S4) at a Thai beverage manufacturer. Operational data from 235 working days covering four truck types (EXP, MAN, CAN, BOT) across 19 bays were used to calibrate the model. A hybrid scenario-reduction approach-combining tail-based extreme-day retention and Ward's hierarchical clustering-compressed the dataset to 40 representative days (including 16 extreme days), reducing computational effort by 83% while preserving workload fidelity (NRMSE = 0.070; Pearson r = 0.873). A total of 200 DES runs (40 days × 5 policies) were conducted, with all improvements confirmed statistically significant (paired t-test, p < 0.001). FIFO dispatching with BOT-to-CAN bay sharing (S1) proved most robust, reducing weighted-average overtime by 43.34% (from 112.94 to 63.99 min/day) with the lowest truck waiting times. While S2 achieved slightly lower absolute overtime (62.79 min/day), it redistributed delays under peak conditions rather than relieving congestion. Sensitivity analysis identified a 90-minute end-of-shift activation window as optimal. S1 is recommended as the operational default, deployable via gate-level queue management without optimization infrastructure. The proposed DES framework offers an efficient, tail-aware platform for evidence-based dock policy evaluation before real-world implementation.