Jurnal Pendidikan Teknik Mesin starting in 2024 migrates to better secure from various unwanted things, including journal hacking and so on. To submit, the author please visit the new website page of our journal at the link https://journal.unnes.ac.id/journals/jptm MIGRATION OFFICIAL STATEMENT HERE P-ISSN 2503-1759 | E-ISSN 2503-1759 First published in June 2001 and since then it is published biannually in June and December. Contains articles lifted from the results of research on field mechanical engineering and the idea of thinking (conceptual) for the development of education and teaching in the field of Mechanical Engineering, in particular at the Institute of Education Personnel (LPTK) and Vocational High School (SMK). The journal is also a means of communication between professors, teachers, instructors, practitioners in business / industry, as well as other related institutions. JPTM Indexed by: DIMENSION | SINTA | GARUDA | DOAJ
BIOMECHANICAL SENSITIVITY OF A THREE-IMPLANT MANDIBULAR REHABILITATION MODEL UNDER ORTHOTROPIC BONE PROPERTY VARIATIONS: A 3D FINITE ELEMENT STUDY
Achieving clinical effectiveness depends on an awareness of the mechanical features of implanted supported mandibular prosthesis. This study used three-dimensional finite element analysis to assess how sensitive a three-implant mandibular arrangement is to changes in the properties of cortical and cancellous bone. Using Ti-6Al-4V material, implants were shown; the bone was defined with orthotropic linear-elastic properties. Young's modulus and shear modulus were systematically changed by 5–15%. Under a 100 N axial load, biomechanical reactions including von Mises stress, principal strain, and displacement were studied with variation coefficients employed to evaluate their consistency. The results showed that stress had minimal changes while strain, particularly in cortical and cancellous bone, was quite sensitive to changes in material characteristics. Young's modulus had a greater influence than shear modulus, and increasing stiffness reduced total displacement. Still, the three-implant system showed consistent load distribution patterns, which suggested strong biomechanical stability. These findings underline how important bone flexibility is for the dynamics of peri-implant tissue and support the application of strain-related metrics for estimating implant placements.
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COMPARATIVE BIOMECHANICAL ANALYSIS OF POSTERIOR MANDIBULAR PREMOLAR IMPLANTS: EFFECTS OF MATERIAL MODELING, CONTACT CONDITIONS, AND LOADING DIRECTION
Posterior tooth loss in the mandibular region may reduce masticatory performance and compromise biomechanical stability, thereby requiring predictable and well-designed implant rehabilitation strategies. This study evaluates the mechanical behavior of an implant–bone system by considering variations in bone material representation (isotropic and orthotropic models), implant–bone interface conditions (fully bonded and frictional contact), and loading orientations (axial and oblique) through a validated three-dimensional finite element analysis (3D-FEA) framework. A full factorial design comprising eight simulation configurations was implemented to assess 15 biomechanical output parameters, including von Mises stress, principal strain, and displacement across implant components and surrounding cortical and cancellous bone tissues. The results indicate that the biomechanical response of the system is strongly dependent on both structural components and loading context. The orthotropic bone model tends to increase stress and deformation responses under specific conditions, whereas oblique loading generally produces higher peak mechanical responses than axial loading. Furthermore, the influence of contact conditions is not uniform but varies according to material assumptions and loading direction, suggesting that simplified fully bonded interfaces may not fully capture realistic implant–bone interactions. Overall, the findings highlight the importance of incorporating anisotropic bone behavior, realistic interface modeling, and clinically relevant loading directions to improve the accuracy of stress prediction around dental implants. This study provides numerical evidence that may support improved implant design strategies and enhance the reliability of future finite element–based biomechanical investigations.
FIRST MANDIBULAR MOLAR IMPLANT SYSTEM UNDER ORTHOTROPIC BONE VARIATIONS: A FINITE ELEMENT SENSITIVITY ANALYSI
Physiological variability in bone mechanical properties may affect load transfer and biomechanical stability in dental implant systems. However, the influence of orthotropic elastic and shear properties on implant–bone biomechanics remains unclear. This study evaluated the sensitivity and robustness of a mandibular first molar implant system to variations in orthotropic bone properties using finite element analysis. A three-dimensional implant–bone model was analyzed under nine material configurations, including gradual orthotropic variations (±15% of baseline) and independent modifications of the elastic and shear modulus. Biomechanical responses were evaluated using von Mises stress, principal stresses, strains, and displacements. Stress concentrations were primarily located at the implant–abutment connection and crestal cortical bone, indicating the main load-transfer pathways. Increasing directional stiffness reduced peri-implant strain and displacement but increased cortical stress, revealing a trade-off between deformation reduction and local stress concentration. Elastic modulus predominantly influenced global stress redistribution, whereas shear modulus had a greater effect on local deformation and peri-implant stability. Strain and displacement were more sensitive to material variations than stress-based parameters. These findings emphasize the importance of orthotropic material representation for realistic biomechanical assessment of dental implant systems under physiological variations in bone quality.
EFFECT OF WOOD GRAIN ORIENTATION ON THE BENDING AND IMPACT STRENGTH OF CARBON FIBER–BALSA WOOD SANDWICH COMPOSITES WITH A POLYESTER RESIN MATRIX
The orientation of wood grains significantly determines the mechanical strength of a sandwich composite material where this study aims to analyze the effect of balsa wood grain orientation variations (0°, 30°, 60°, and 90°) as a core material on flexural and impact strength. The materials used in this research consist of a balsa wood core carbon fiber skins, and a polyester resin matrix, fabricated using the vacuum bagging method. The testing procedures include the three-point bending test referring to the ASTM C393 standard, and the drop weight impact test adhering to ASTM D7136. The experimental data were analyzed to evaluate the mechanical strength and failure characteristics resulting from flexural loading and sudden impact. The results indicate that the straight grain orientation (0°) provides a maximum flexural strength of 22.77 MPa and the best impact resistance compared to other grain directions. This study confirms that balsa wood grain orientation has a significant influence on mechanical strength establishing the straight grain as the most optimal configuration for lightweight structural applications that require weight efficiency and high mechanical performance.
APPLICATION OF FLIPPED CLASSROOM AND AI BASED ON IGNASIAN PEDAGOGICAL PARADIGM IN MACHINE MODELING CLASSES
This research develops an innovative learning model in the machine modeling classroom using flipped classroom and generative AI methods and it is based on ignasian pedagogy. This research was held parallel in 2 classes, class B1 using the flipped classroom method and class B2 using conventional methods. This study aims to determine the significance of increasing final scores using the independent t-test in the application of flipped classroom in machine modeling classes with assessment rubrics based on the 4C components, namely competence, conscience, compassion, and commitment. The results of the t-test showed that the final score of class B1 was higher than class B2 even though it was not statistically significant. Although statistically insignificant, qualitative observations show that increased engagement, preparedness, and conceptual mastery among students using the FC–Gen AI–IP model. This study highlights the potential of integrating Gen AI and IP into the flipped classroom framework to enrich learning experiences in CAD-based engineering courses.
THE DETERMINATION OF THE OUTSIDE MOLD DIMENSION FOR OPTIMIZATION OF THE CLAMPING FORCE OF THE PLASTIC INJECTION MACHINE
Injection molding is a popular method that is used to make plastic products due to high productivity, efficiency, and manufacturability. This paper presents the effect of the mold outside dimension on a suitable injection molding machine. It is to capacity in relation to production cost. This research is important as a guide for determining the outer dimensions of the mold to suit the machine being used. The smallest size isn't necessarily the most efficient, as there are minimum dimensions that can be used. The research included calculations for product weight, cycle time, tie bar distance, and minimum mold height. The compatibility between the injection machine used and the mold's outer dimensions is crucial. In this research, the mold height needs to be increased from the previously designed smallest dimensions.
clamping force, injection, machine, mold, plastic
COMPREHENSIVE REVIEW OF THE APPLICATION OF HYBRID NANOFLUIDS (HNF) IN MINIMUM QUANTITY LUBRICATION (MQL) FOR SUSTAINABLE MACHINING
Conventional cutting fluids in machining cause environmental and economic concerns. Minimum Quantity Lubrication (MQL) offers a sustainable alternative but faces cooling and lubrication limitations. Integrating hybrid nanofluids (HNF) into MQL significantly enhances machining performance. This review systematically analyzes HNF-MQL applications in continuous machining, examining improved cooling-lubrication mechanisms, performance outcomes, and sustainability. Results indicate HNF consistently outperforms single nanofluids, reducing cutting force, tool wear, and improving surface quality across various hard-to-machine materials. HNF-MQL also lowers fluid consumption, energy use, and environmental impact. However, challenges like nanoparticle stability, cost, and production scalability hinder widespread adoption. HNF-MQL presents an effective green machining strategy, with future research needed in material optimization, advanced delivery systems, and deeper mechanistic understanding.
DEVELOPMENT OF LEARNING MEDIA TO IMPROVE STUDENT LEARNING OUTCOMES ON PRODUCT BRANDING MATERIALS IN VOCATIONAL HIGH SCHOOLS
The purpose of this study is to analyze the needs of teachers and students for learning media, to determine the feasibility of learning media, and to measure the effectiveness of this learning media on Shiva learning outcomes. This type of research is Research and Development (R&D). With the validation of the research instrument, it is then continued with the research procedure using 10 stages, and quantitative descriptive data analysis techniques. The results of the media feasibility test obtained a percentage of 95% for the media assessment so that the product was categorized as "very feasible", and 93% for the assessment of material experts so that the product was also categorized as "very feasible". Student learning outcomes at n-gain value get an average score of 0.8547, meaning that the increase in student learning outcomes is in the "high" category. The researcher suggested that the use of android-based learning media to improve student learning outcomes on product branding materials could be an alternative and reference for learning media.
IMPLEMENTATION OF NANO COATING CERAMICS TECHNOLOGY IN VOCATIONAL LEARNING TO IMPROVE THE CORROSION RESISTANCE OF AUTOMOTIVE COMPONENTS IN COASTAL AREAS
Coastal flooding creates a highly corrosive environment that damages motorcycle components. This study evaluates the synergistic effects of proper repainting procedures and nano-ceramic coatings on the corrosion resistance of the main standard of motorcycles. Laboratory experiments were conducted using a post-assay-only control group design with four treatments: nanocoating, repainting, a combination of both, and untreated controls. The samples underwent accelerated corrosion testing through immersion for 15 days in a 3.5% NaCl solution. The combined treatment shows superior performance, achieving the lowest corrosion rate (0.15 mm/year), perfect adhesion (0B), and highest hardness (4H). This represents a reduction in corrosion rate of about 91% compared to control. The results significantly show that integrating a multi-layer repainting foundation (primer, surfacer, top layer) with a SiO₂-based nano-ceramic top layer creates a synergistic barrier system. This approach is recommended as a highly effective and practical solution to significantly extend the life of assets and improve operational safety in corrosion-prone areas.
Corrosion Resistance of Mainstand, Nano-Ceramic Coating, Automotive Repainting Procedure, Coating Protection
A REVIEW ON THE POTENTIAL OF INDONESIAN NATURAL FIBERS AS BALLISTIC COMPOSITE MATERIALS
Ballistic composites are key materials in protective applications designed to absorb and dissipate the impact energy of projectiles. Currently, the reliance on synthetic materials such as aramid fibers (Kevlar) and ultra-high molecular weight polyethylene (UHMWPE) faces challenges including high production costs, environmental impact, and import dependency. Indonesia, with its abundant natural fiber resources such as ramie, abaca, bamboo, and sisal, has great potential to develop sustainable and self-reliant ballistic composite materials. This review aims to systematically examine the potential of Indonesian natural fibers as ballistic composite materials by analyzing their mechanical properties, comparing them with ballistic requirements, and identifying key challenges and development strategies. The study concludes that although natural fibers exhibit promising mechanical properties, they face major limitations such as hydrophilic nature and variability in characteristics. However, chemical treatments and surface engineering (such as reinforcement with SiO₂, CNT, or SiC) have been shown to improve fiber–matrix interfacial performance, thereby opening opportunities for the utilization of Indonesian natural fibers in effective and environmentally friendly ballistic composites.
The Effect of Fuel Injection Duration on Exaust Gas Emissions of a 4-Stroke Engine 113.68 CC Using Bioethanol Fuel
In Indonesia, the number of motor vehicles using fuel as an energy source is rising quickly. The government has developed renewable energy to reduce fuel consumption because, according to the Downstream Oil and Gas Regulatory Agency (BPH Migas), the consumption of gasoline-type fuels in 2017 was 1,858,875 L/Quarter. Determining the impact of using bioethanol with different injection times on exhaust gas emissions was the aim of this study. Bioethanol is an environmentally friendly alternative fuel for cars that uses less fuel. It is a renewable energy source made from vegetable sources. Variations in fuel injection duration and exhaust gas emission are the main subjects of this study. With no modifications to compression, the engine operates under standard conditions. A gas analyzer and engine speeds of 1500, 2000, 3000, 4000, and 5000 Rpm were used in the study. According to the study's findings, the amount of CO exhaust gas dropped. At 5000 RPM for 4 ms, the lowest CO in bioethanol fuel is 1.21%. With bioethanol fuel, the amount of HC exhaust gas emissions has dropped. 710 ppm at 3000 Rpm for 4 ms is the lowest HC level. When using bioethanol as fuel, the amount of CO2 emissions rises. The maximum CO2 concentration is 6.50% at 5000 RPM for 4 ms. The maximum amount of O2 emissions from bioethanol fuel is recorded at 1500 RPM for 4 ms.
ANALYSIS OF MECHANICAL CHARACTERISTICS OF TOOTH BUCKET EXCAVATOR BASED ON DIFFERENT GRADE LEVELS
The purpose of this study is to comprehend the microstructure and hardness value of three distinct tooth bucket manufacturers. Three manufacturers' excavator tooth buckets—Canada Grade, China Grade A, and China Grade C—are compared for their mechanical characteristics. Among the tests are the Vickers method for measuring hardness, optical microscopy for examining microstructure, and chemical composition analysis. According to the results, the primary elements in all three specimens—carbon, silicon, manganese, and chromium—meet the DIN Grade 25CrMo4 standard. The martensite phase, which gives the Canada product its hardness and resistance to deformation, dominates its microstructure. The China Grade C product, on the other hand, has a more prominent ferrite phase, which raises ductility while decreasing hardness. China Grade C (570.24 HVN) had the highest hardness test value, followed by China Grade A (517.67 HVN) and Canada (468.09 HVN). This demonstrates that while Canada excels at withstanding heavy loads without damage, China Grade C is better suited for applications needing high wear resistance. Users of heavy machinery can use this study as a scientific guide when choosing bucket nails based on operational requirements, including material toughness and wear.
tooth bucket, vickers hardness, microstructure, martensite phase, ferrite phase.
Effect of Implant Diameter on Biomechanical Response of Straight Multi-Unit Abutments in Mandibular All-on-3: A 3D Finite Element Study
This study evaluates the biomechanical performance of varying implant fixture diameters in mandibular edentulous rehabilitation using the All-on-3 concept with straight multi-unit abutments. A three-dimensional finite element model of a mandible segment was constructed and subjected to static occlusal loading conditions derived from clinical bite force data. Three Brånemark-type implants with diameters of 3.75 mm, 4.0 mm, and 5.0 mm were analyzed using ANSYS Workbench to assess von Mises stress, equivalent strain, and factor of safety (FOS) in abutment and screw components. The results revealed that increasing the fixture diameter to 5.0 mm reduced von Mises stress by 12.8- 15.0% in abutments and 17-44.3% in screws across anterior and posterior positions. Similarly, strain decreased by up to 11.1% in abutments and 45.0% in screws. The highest FOS (37.48 for abutment, 25.09 for screw) was recorded at the 5.0 mm diameter, confirming enhanced safety margins. However, posterior implants experienced stress transfer from abutment to screw components as diameter increased, particularly due to local stiffness mismatch and cantilever effects. While all configurations remained below Ti-6Al-4V yield strength, the posterior 3.75 mm setup yielded the lowest FOS (1.45), suggesting a higher mechanical risk. These findings emphasize the need for careful diameter selection in posterior All-on-3 designs.
Finite element analysis, All-on-3, mandibular edentulous, full-arch prosthesis, implant diameter, biomechanical.
THREE-DIMENSIONAL FEA OF FIXTURE DIAMETER INFLUENCE ON ABUTMENT AND SCREW IN ANTERIOR MAXILLA BRIDGES
Numerical simulation-based biomechanical evaluation was used to analyze the effect of implant diameter variation on stress and strain on the abutment and screw using the Finite Element Method (FEM). Modeling was performed based on CBCT data and simulated in ANSYS Workbench 2023 R1. Three implant diameters were tested (3.75 mm, 4.3 mm, and 5.0 mm), each subjected to a force of 204.1 N at a 45° angle to mimic anterior functional conditions. The 4.3 mm diameter produced the highest stress on the abutment (213.62 MPa), while the 5.0 mm diameter showed the lowest stress (192.5 MPa) and minimum strain (0.00178). The 5.0 mm diameter also reduced the load on the screw, indicating a more stable load distribution. Therefore, this diameter is recommended as the optimal biomechanical configuration for anterior implant bridges, while considering anatomical limitations.
Biomechanical Evaluation of Implant Angulation on the First Mandibular Premolar: A 3D Finite Element Study
The design and orientation of dental implant connections play a critical role in biomechanical success, particularly in the posterior mandibular region, which is subjected to high occlusal loads. This study aims to evaluate the effect of varying abutment angulations (0°, 15°, and 25°) on stress distribution, strain, and safety factor in a reverse-buttress implant system using the Finite Element Analysis (FEA) approach. A 3D implant model was simulated within an idealized bone block using ANSYS software, applying a physiological static load of 240 N. The results showed that increasing abutment angulation significantly elevated both maximum stress and strain, particularly in the screw component, which experienced a peak stress of 455.89 MPa at 15°. The safety factor, calculated based on the yield strength of titanium grade 5 (880 MPa), decreased from 14.18 (0° abutment) to 2.94 (25° abutment). Although all configurations remained within safe limits (>1.5), the axial (0°) configuration demonstrated the most stable load distribution and the highest safety margin. This study underscores the importance of considering abutment angulation in implant planning and supports the use of safety factor–based FEA as a predictive tool for assessing implant structural safety.
FIXTURE DIAMETER INFLUENCE ON BIOMECHANICAL PERFORMANCE OF DENTAL IMPLANT ABUTMENT AND SCREW: A 3D FEA STUDY
Dental implant stability hinges on fixture design, particularly diameter, influencing biomechanical performance. This study evaluates the impact of fixture diameter on von Mises stress, strain, and factor of safety in the abutment and screw of posterior dental implants using finite element analysis. A three-dimensional model of a mandibular first molar implant was developed with fixture diameters of 3.75, 4.0, and 5.0 millimeters, using Ti-6Al-4V and static loading simulating maximum voluntary clenching (177.38 N). Results show that the 5.0-millimeter diameter with a wider abutment reduces stress by 23.7 percent in the abutment and 33.9 percent in the screw, strain by 23.7 and 33.1 percent, respectively, and improves factor of safety, compared to 3.75 millimeters. The 5.0-millimeter diameter optimizes biomechanical stability, enhancing long-term implant success in posterior mandibular applications.
FINITE ELEMENT STUDY ON ANGULATED ABUTMENTS IN MAXILLARY POSTERIOR DENTAL IMPLANTS
Dental implants in the posterior maxilla often require angulated abutments due to anatomical limitations. However, increased abutment angulation may influence stress distribution and compromise mechanical integrity. This study aimed to evaluate the biomechanical behavior of implant components with 15°, 17°, and 20° abutment angulations using three-dimensional finite element analysis (FEA). A static vertical load of 276 N was applied to a D4-type bone block model. Results showed that higher abutment angles led to increased von Mises stress and strain, particularly on the abutment U-profile and the screw head. Despite the rising stress, all configurations maintained safety factors above 1.5. These findings indicate that angled abutments up to 20° are mechanically safe under axial loading conditions, supporting their use in clinically challenging posterior maxillary regions.
THE EFFECT OF IMPLANT DIAMETER ON STRESS, STRAIN, AND SAFETY FACTOR IN SCREWS AND ABUTMENTS BASED ON FEA
The loss of anterior teeth has a significant impact on masticatory function and facial aesthetics, making dental implants a widely used rehabilitative solution. The success of implants is greatly influenced by geometric design, particularly the diameter of the fixture, which plays a role in distributing load. This study aims to analyze the influence of variations in implant diameter on stress distribution, strain, and safety factor in the screw and abutment areas using a three-dimensional Finite Element Analysis (FEA) approach. Three implant models with fixture diameters of 3.75 mm, 4.00 mm, and 5.00 mm were simulated using a vertical physiological load of 130.5 ± 73.6 N, assuming Ti-6Al-4V material and orthotropic properties of the mandibular bone. The results showed that Model 2 (4.00 mm diameter) had the most balanced stress distribution and the highest safety factor value at the abutment (12.251), while Model 3 exhibited the lowest stress and strain at the screw. Model 1 had the lowest biomechanical performance with the highest stress and strain and the lowest abutment safety factor (10.611). It can be concluded that variations in fixture diameter significantly affect the mechanical performance of the implant system, and a diameter of 4.00 mm is recommended as the most optimal design to support long-term strength and stability.
Application of MULTIMEDIA Powerpoint Assisted Learning to Improve Learning Outcomes of Knowledge of the function of Fracture Machine Parts
The purpose of the research conducted to determine the effect of using PowerPoint multimedia on improving student learning outcomes in the subject of milling machine parts at SMK IPT Karangpanas. The background of this research is based on poor student learning outcomes, which are below the Graduation Threshold Value (KKM). Before conducting research, the feasibility of media and material was tested by experts with a percentage of 83% so that the material and media were suitable for use. The method used is quantitative experimental research with a two-group pre-test and post-test experimental model. Samples from two XI classes were taken randomly, with one experimental class and the other as a control class. Data were collected through questions in the form of pretest and posttest, and analysed using normality test, paired sample t-test, independent sample t-test, and N-Gain analysis. Results showed a significant improvement in learning outcomes in the experimental class compared to the control class, with a higher mean posttest score. The independent sample t-test showed significance <0.001, and the mean N-Gain of 0.4713 was classified as moderate. Thus, the use of PowerPoint multimedia was proven effective in improving students' learning outcomes.
The Use of E-Modules to Enhance Students’ Cognitive Achievement in Understanding Milling Machine Components
Penelitian ini bertujuan untuk mengembangkan dan mengevaluasi keefektifan e-modul interaktif sebagai media pembelajaran untuk meningkatkan hasil belajar kognitif siswa pada pokok bahasan komponen mesin frais. Penelitian ini menggunakan metode Research and Development (R&D) dengan model pengembangan 4D (Define, Design, Develop, dan Disseminate). Subjek penelitian adalah siswa kelas XI Program Studi Teknik Pemesinan SMK Negeri 5 Semarang. Instrumen pengumpulan data meliputi soal pretest dan posttest, lembar validasi ahli materi dan media, serta angket respon siswa. Hasil validasi menunjukkan bahwa e-modul sangat layak digunakan dalam proses pembelajaran. Hasil uji coba menunjukkan adanya peningkatan hasil belajar siswa yang signifikan setelah menggunakan e-modul, dibuktikan dengan selisih skor pretest dan posttest yang dianalisis menggunakan uji-t. Rata-rata skor N-Gain menunjukkan adanya peningkatan yang cukup. Selain itu, respon siswa terhadap penggunaan e-modul tergolong sangat positif. Oleh karena itu, e-modul dianggap efektif sebagai media pembelajaran interaktif untuk meningkatkan pemahaman siswa tentang komponen mesin frais. Penelitian ini merekomendasikan penggunaan e-modul sebagai alternatif inovatif dalam pembelajaran berbasis teknologi dalam pendidikan kejuruan.
module, milling machine, cognitive learning, instructional media development, R&D
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UTILIZING E-MODULES TO ENHANCE STUDENTS’ ACHIEVEMENT IN UNDERSTANDING SMAW WELDING DEFECT ANALYSIS AT SMK N 5 SEMARANG
Understanding welding defect analysis is a crucial competency in vocational welding education, especially in ensuring the quality and safety of welding outcomes. However, many students struggle to master this material due to the lack of interactive and adaptive learning media. This study aims to develop and implement an electronic module (e-module) to enhance student learning outcomes in Shielded Metal Arc Welding (SMAW) defect analysis at SMK N 5 Semarang. The research uses a Research and Development (R&D) approach based on the 4D model: Define, Design, Develop, and Disseminate. A one-group pre-test post-test design was used, involving 33 Grade XI Mechanical Engineering 2 students. The e-module was validated by experts and classified as "Valid" in terms of content, media, and assessments. Students' average scores increased from 40.61 in the pre-test to 78.64 in the post-test. Statistical analysis using the Wilcoxon Signed-Rank Test and paired t-test showed a significant difference (p < 0.001). The average N-Gain score was 0.63, indicating a moderate improvement. The results confirm that the e-module is both feasible and effective. It enhances students’ conceptual understanding and supports independent, technology-based learning aligned with the characteristics of digital-native learners.
ANALYSIS OF THE APPLICATION OF GAME BASE LEARNING IN VOCATIONAL EDUCATION OF LATHE MACHINING
This article examines the implementation of the Game-Based Learning (GBL) model in lathe machining education at vocational high schools (SMK). Lathe machining is a manufacturing process that produces cylindrical machine components using a lathe, in which the workpiece rotates and is subjected to a single-point cutting tool aligned with the workpiece axis. To improve the quality of lathe machining education, an effective instructional model such as Game-Based Learning is needed. This research applies a Systematic Literature Review (SLR) approach to identify and analyze six relevant studies published between 2020 and 2025 based on inclusion criteria. The findings show that GBL has a positive impact on increasing students’ learning motivation, engagement, and learning outcomes in lathe machining practice. The study concludes that GBL is an effective solution for practice-based learning in vocational education and recommends its wider adoption in technical vocational training.
THE EFFECTIVENESS OF LEARNING MEDIA BASED ON YOUTUBE VIDEO TUTORIALS ON STUDENT LEARNING OUTCOMES PER WELDING PRACTICE
This study aims to analyze the effectiveness of YouTube-based video tutorial learning media in improving students' cognitive learning outcomes in Shielded Metal Arc Welding SMAW practice at SMK Negeri 4 Semarang. The background of this research is based on the limited use of contextual and engaging instructional media in vocational education, which leads to low conceptual understanding and applied skills among students. The research employed a quasi-experimental method with a pretest-posttest control group design. The sample consisted of 60 tenth-grade students from the Mechanical Engineering Expertise Program, selected through purposive sampling and divided into two groups: an experimental group that used YouTube-based instructional videos and a control group that applied conventional lecture methods. The research instrument comprised 20 validated multiple-choice questions. Data was analyzed using the Shapiro-Wilk normality test, Levene's homogeneity test, independent t-test, and N-Gain analysis to assess learning improvement. The results indicated a significant difference between the experimental and control groups p< 0.001, with the experimental group achieving an average post-test score of 84.50 and an N-Gain of 0.6100 high category. In contrast, the control group scored an average of 75.33 with an N-Gain of 0.4155 medium category. These findings suggest that using YouTube video tutorials as instructional media effectively enhances students' learning outcomes in welding practice while also creating a more contextual, visual, and student-centred learning process suited to the learning styles of vocational students.
DEVELOPMENT OF MOTORCYCLE TUNE UP TUTORIAL VIDEO MEDIA FOR GRADE X STUDENTS OF MOTORCYCLE TECHNIQUE AND BUSINESS EXPERTISE COMPETENCY AT SMK MUHAMMADIYAH BAWANG
This study aims to develop learning media in the form of a video tutorial on motorcycle tune-up practices for class X students of Motorcycle Engineering and Business Expertise at SMK Muhammadiyah Bawang. The method used is research and development (R&D) by adapting the Borg & Gall model to the final product trial stage. Data collection was carried out through observation, interviews, expert validation questionnaires, student response questionnaires, and practical skills tests. The results of the study showed that the video tutorial media developed obtained the category "feasible" to "very feasible" from the material and media aspects, and received a positive response from students. The use of video tutorials has proven effective in improving students' understanding of concepts and practical skills, as well as supporting student-based learning approaches. This study contributes to the development of digital-based learning media in vocational education environments.
THE IMPACT OF QUALITY, VISIONARY, AND ENTREPRENEURIAL LEADERSHIP OF VOCATIONAL SCHOOL PRINCIPALS ON THE SUCCESS OF SCHOOL MANAGEMENT
This study investigates the influence of school principals’ leadership styles, specifically quality leadership, visionary leadership, and entrepreneurial leadership, on the success of school management in Vocational Schools specialising in Technology and Engineering in Yogyakarta. Employing a descriptive quantitative approach with an ex-post facto design, data were gathered from 282 teachers selected through cluster sampling and stratified random sampling across 16 Vocational schools of various accreditation levels. The results reveal significant positive influences of quality leadership (31.5%), visionary leadership (11.1%), and entrepreneurial leadership (35.7%) on school management success. Simultaneously, the combined leadership styles contributed 37.3% to the variance in management success. These findings highlight the importance of multifaceted leadership in improving educational outcomes and suggest the need for policy reinforcement to support effective school governance.
school leadership, quality leadership, visionary leadership, entrepreneurial leadership, school management.
ANALYSIS OF EXHAUST EMISSIONS, NOISE, AND PERFORMANCE OF A 110CC MOTORCYCLE USING A PERFORATED-CLOSE CONICAL SILENCER MUFFLER
This paper analyzes the exhaust emission, noise, and performance of 110cc motorcycles experimentally through PCCS exhausts compared to standard exhausts. This study adopts an experimental method involving three tests: exhaust emission testing based on the SNI 09-7118.1-2005 standard, noise measurement using the static test procedure according to the UN-R 41-04 standard, and performance evaluation conducted with an inertial dynamometer. Implementing the PCCS exhaust system on a 110 cc automatic motorcycle positively impacts exhaust emissions, noise levels, and engine performance. Compared to the standard exhaust, the PCCS significantly reduces CO and HC emissions by 78.99% and 55.99%, respectively, while maintaining noise levels within regulatory limits in urban conditions. In terms of performance, the PCCS delivers higher torque and power output, particularly in the 3500–5500 RPM range, which aligns with typical riding conditions. These improvements are attributed to the system’s efficient exhaust flow and reduced backpressure. The PCCS exhaust presents a promising solution for enhancing environmental sustainability, performance, and rider comfort in small-displacement motorcycles.
ENHANCING STUDENT CREATIVITY IN CNC COURSES THROUGH MARKETPLACE-BASED TEACHING FACTORY: A CLASSROOM ACTION RESEARCH
The rapid transformation brought by Industry 4.0 and Society 5.0 demands vocational education to produce graduates who are not only technically competent but also creative and entrepreneurial. This study aims to enhance student creativity in CNC (Computerized Numerical Control) learning by implementing a marketplace-based Teaching Factory model. Using a Classroom Action Research (CAR) design, the study involved 20 students of the Mechanical Engineering Education Program over two learning cycles. Each cycle included planning, implementation, observation, and reflection stages. The results showed significant improvements across four assessed aspects: technical skills (from 74.1 to 86.6), product design (from 75.1 to 87.9), marketing (from 73.5 to 86.5), and reflective learning (from 78.2 to 91.0). The marketing aspect experienced the highest gain, indicating that digital marketplaces provide an effective platform for practical entrepreneurial learning. This study concludes that integrating marketplace platforms into Teaching Factory learning can significantly foster creativity and entrepreneurial skills in vocational students.
DESIGN OF DRYER FOR SMALL FARMERS BASED ON THE STUDY OF ERGONOMICS THERMAL ENGINEERING APPLICATION
Ergonomics thermal engineering combines the principles of thermal engineering and ergonomics to design systems and products that optimize energy and resources, improve worker thermal comfort, and reduce thermal stress and fatigue. Small farmers still dry post-harvest food under direct sunlight in open areas. This process produces less than optimal drying thermal temperatures, which impacts long drying times, and dried food is susceptible to dust and animal faeces exposure. In addition, exposure to sunlight on workers causes additional workloads that affect fatigue. This can be overcome by utilizing solar collectors through dryer design based on anthropometric data of workers as users. The dryer was designed through an ergonomics thermal engineering study. Based on anthropometric data and percentile calculations, dimensions were obtained for the dryer design, such as the bottom shelf with a height from the floor of 66.88 cm based on the knuckle, the top shelf height of 123.8 cm from the floor based on standing eye height, and the height of the drying room air chimney from the floor is 177.59 cm based on the height of the upper reach. To avoid new problems with the dryer application, a table was designed as a workaid with a height of 84.31 cm based on the height of the standing elbow. Applying the principles of ergonomics thermal engineering can create systems and products that are more comfortable, safe, and efficient for workers.
EFFECT OF WELDING CURRENT ON LOW CARBON STEEL CHARACTERISTICS IN SMAW CLADDING PROCESS
The electric current magnitude is a fundamental parameter that directly affects penetration characteristics and weld bead geometry. This study analyzes the effect of current variations on physical and mechanical properties in the cladding process using the Shielded Metal Arc Welding (SMAW) method. The materials used are low-carbon steel and HV-600 electrodes with a diameter of 3.2 mm. The SMAW method was applied with current variations of 100 A, 120 A, 140 A, and 160 A. The tests carried out were NDT liquid penetrant, macro structure, micro structure and Vickers hardness. The results indicate a positive correlation between increasing current and hardness values in the weld area, with the highest hardness recorded at 665.803 HVN at 160 A and the lowest at 515.143 HVN at 100 A. Meanwhile, in the Heat Affected Zone (HAZ), a non-linear pattern was observed, with a maximum hardness of 263.237 HVN at 120 A and a minimum of 219.110 HVN at 140 A. Microstructural analysis revealed the formation of ferrite, pearlite, bainite, and martensite phases in the weld area, providing insights into optimizing welding parameters to enhance the mechanical properties of low-carbon steel cladding.
ERGO-MECHANICAL APPLICATIONS IN SMALL-SCALE SMAW WELDING TABLE DESIGN
SMAW (shielded metal arc welding) is widely used in almost all types of welding work, including small industries. In small industries, workers doing SMAW welding work are generally done by squatting. This work posture causes musculoskeletal complaints in workers as a result of unnatural work postures. To overcome this is done through ergo-mechanical applications to create aids in the form of welding tables. Ergonomically based on worker anthropometric data, while mechanically with the selection of strong, lightweight, and affordable materials in terms of cost. The results of testing the welding table design based on ergo-mechanical applications provided a decrease in musculoskeletal disorders in workers. Workers' musculoskeletal disorders can be reduced by 24.61%. From the moderate category, an average of 51.6, to the light category, with an average of 38.9. The ergo-mechanical application will produce work tools that are comfortable for workers to use and meet technical standards related to specifications as a description of the technical characteristics of a work tool.
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