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Jurnal Vokasi Mekanika
Published by Universitas Negeri Padang
ISSN : 26561697     EISSN : 26562812     DOI : https://doi.org/10.24036/vomek.v4i3
Core Subject : Education, Engineering,
Education Mechanical Engineering
Jurnal Vokasi Mekanika menyambut baik kiriman yang memberikan wawasan tentang isu-isu terkini dan utama yang berkaitan dengan pendidikan kejuruan dan teknologi serta ilmu Keteknikan dalam bidang Teknik Mesin. Jurnal ini menyediakan tempat bagi para peneliti dan praktisi untuk mendiskusikan, mengejar, dan mempromosikan pengetahuan di bidang studi pendidikan teknologi kejuruan dan ilmu Keteknikan dalam bidang Teknik Mesin yang sedang berkembang pada saat sekarang ini. Bahasa naskah ditulis dalam bahasa Indonesia. Harus ada diskusi kritis tentang isu-isu baru dan signifikan dan kontribusi ke bidang terkait. Artikel dapat berasal dari salah satu bidang berikut: Teori, Strategi, Pendekatan, Metode Atau Model Pembelajaran TVET Penerapan dan Pengembangan Media, Modul, Bahan Ajar dan Buku Ajar Manajemen dan Kebijakan TVET Pengembangan Kurikulum TVET Evaluasi Program dan Pembelajaran TVET Penerapan Teknologi Kejuruan Terkait TVET Pengembangan Profesionalitas Guru TVET Energi dan energi terbarukan Sistem produksi dan Manufaktur Rekayasa bahan Teori dan aplikasi dinamika fluida komputasi Ilmu ilmu Teknik Mesin Lainnya.
Arjuna Subject : Teknik (semua kategori) - Teknik Mesin
Articles 437 Documents
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Calculation of High Pressure Heater Efficiency in the Feedwater System of PT PLN IP Teluk Sirih Unit 2 Steam Power Plant Zulvani Adha; Andre Kurniawan; Arwizet K; Yolli Fernanda
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 1 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/v1frxb70

Abstract

PT PLN IP Teluk Sirih is a coal-fired steam power plant that supplies electricity to the West Sumatra region. In steam power plants, the High Pressure Heater (HPH) functions as a heat exchanger that preheats feedwater before entering the boiler by utilizing extraction steam from  turbine. Damage or performance degradation of the HPH can reduce its effectiveness and lifespan, decrease feedwater temperature, increase the required heating in  boiler, raise fuel consumption, and ultimately lower the overall efficiency of the power plant cycle. Therefore, this study aims to determine the efficiency of HPH at PT PLN IP Teluk Sirih Unit 2 in order to support proper maintenance planning and reduce operational costs. The research employs a quantitative method with a descriptive–analytical approach using actual operational data obtained from the Distributed Control System (DCS) of PLTU Teluk Sirih Unit 2. The efficiency of HPH is calculated by comparing the heat released by the steam  and the heat absorbed by the feedwater  or HPH 1 and HPH 2. The variables used include the feedwater inlet temperatures of 192.9 °C for HPH 1 and 141.5 °C for HPH 2. The results show that the efficiency of HPH 1 is 91.26%, while the efficiency of HPH 2 is 88.11%. For HPH 1,  and  are 49,552,500 kJ/h and 54,297,300 kJ/h, respectively, whereas for HPH 2,  and  are 71,613,300 kJ/h and 81,288,480 kJ/h. These results indicate that a higher inlet temperature leads to a greater ratio between  and  , and consequently to a higher HPH efficiency.  
Numerical Simulation of the Effect of Blade Shape on Vertical Axis Wind Turbine Using NACA 0015, NACA 4415, and NACA 7510 Rezki Alhakim; Randi Purnama Putra; Yolli Fernanda; Fitrah Qalbina
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 1 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/8fw5gp43

Abstract

Energy is a resource that can be used to perform various tasks, including fuel, electricity, mechanical energy, and heat. With technological advances and global economic development, the demand for electricity will continue to increase. This drives various research efforts towards alternative energy sources, ranging from the development of existing tools to the creation of new innovations. Wind turbines work by utilizing the kinetic energy of the wind flow to rotate the blades, which are then converted into electrical energy through a generator system. The purpose of this study is to analyze the effect of curvature shape on the Lift Coefficient (Cl), Drag Coefficient (Cd), and Power Coefficient (Cp) of vertical axis wind turbine blades. Simulations were carried out in 3D using ANSYS Fluent software and the SST turbulence model, with wind speeds ranging from 4 to 7 m/s. The aerodynamic profiles analyzed were NACA 0015, NACA 4415, and NACA 7510. Aerodynamic simulations of vertical axis wind turbines were carried out using a steady-state approach with a multi-reference frame (MRF) rotation model to obtain the average aerodynamic characteristics of the rotor. The simulation results show that NACA 4415 produces the best Cl value with relatively controlled Cd, while NACA 0015 shows the worst aerodynamic performance. NACA 7510 produces the highest Cp value at all wind speed variations, despite low Cl and high Cd values, indicating that the drag mechanism dominates torque generation at low speeds.
Analysis of the Effect of Feed Rate, Spindle Speed and Coolant on Surface the Roughness of ST 37 Steel in the Turning Process Rahmatul Fauzan Mulyadi; Syahril; Rifelino; Zainal Abadi
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 2 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/epr1f741

Abstract

Surface roughness is an important parameter in turning processes, as it directly affects the performance and service life of mechanical components. This study aims to examine the influence of feed rate, spindle speed, and coolant application on the estimated surface roughness (Raest) of ST 37 steel under conventional turning conditions. A 2³ full factorial experimental design was employed, involving eight treatment combinations consisting of two feed rate levels (0.040 and 0.100 mm/rev), two spindle speed levels (315 and 400 rpm), and two cooling conditions (with and without coolant). Surface roughness estimation was carried out using digital image analysis with ImageJ software based on optical microscope images. The analysis utilized gray-level intensity distributions, which were then converted into roughness values using an empirical scaling approach. The results indicate that increasing the feed rate led to a rise in Raest ranging from 1.74% to 7.11%, while higher spindle speeds contributed to an increase in surface roughness between 4.54% and 11.91%. In contrast, the use of coolant reduced surface roughness by an average of 9.20%, mainly due to its role in minimizing heat and friction during machining. The optimal parameter combination was obtained at a spindle speed of 315 rpm and a feed rate of 0.040 mm/rev with coolant, producing an Raest value of 1.495 µm, which falls within ISO roughness class N7. Overall, all specimens were classified within ISO N7, indicating a semi-finishing surface quality.
Effect of Rice Husk Ash and Clay Powder as Cooling Media in Post Weld Heat Treatment (PWHT) on The Impact Toughness of SMAW-Welded SS400 Steel Angga Hermawansyah; Zainal Abadi; Delima Yanti Sari; Rifelino
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 2 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/f6gkaq38

Abstract

This study investigates the effect of variations in cooling media during Post Weld Heat Treatment (PWHT) on the impact toughness of low carbon steel SS400. The main problem addressed in this research is how differences in cooling medium characteristics influence the cooling rate, which subsequently affects the impact toughness of welded material. The objective of this study is to determine the effect of using rice husk ash, clay, and air as cooling media on the impact toughness value of SS400 steel. The experimental method was employed by applying PWHT to SMAW-welded specimens, followed by Charpy impact testing to obtain the final deflection angle, which was then converted into impact energy and impact value (HI). The results show that clay cooling medium provides the highest average impact toughness value of 1.175 J/mm², followed by rice husk ash at 1.107 J/mm², while air cooling yields the lowest value of 0.845 J/mm². These differences indicate that the thermal characteristics of the cooling media significantly influence the material’s ability to absorb energy before fracture, which is related to the stability of the cooling rate during the PWHT process. It can be concluded that variations in cooling media affect the impact toughness of SS400 steel, where more stable cooling conditions lead to higher toughness values.
Analysis Of The Effect Of Penstock Diameter Variation And Nozzle Flow Velocity On Pelton Turbine Performance Using Computational Fluid Dynamics (CFD) Revaldo Nur Hidayat; Randi Purnama Putra; Yolli Fernanda; Fitrah Qalbina
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 2 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/18k9e415

Abstract

The performance of a Pelton turbine in micro-hydropower plants is influenced by penstock design and fluid flow conditions. Variations in penstock diameter can lead to changes in head loss, flow velocity, and energy transfer efficiency. This study aims to analyze the effect of penstock diameter variation and nozzle flow velocity on Pelton turbine performance under different head conditions using the Computational Fluid Dynamics (CFD) method.Simulations were conducted using penstock diameters of 4 inches, 5 inches, and 6 inches with ANSYS software. The results show that the respective head losses are 0.010 m, 0.006 m, and 0.0028 m, indicating that larger diameters reduce friction losses in the flow. The corresponding nozzle velocities are 8.90 m/s, 9.08 m/s, and 8.64 m/s, with the highest value observed at the 5-inch diameter due to the balance between flow rate and energy losses. The resulting torque values are 2.13 Nm, 2.55 Nm, and 2.60 Nm, while the rotor rotational speeds are 150.87 W, 189.07 W, and 194.90 W. The effective power generated is 65.59 W, 80.21 W, and 77.79 W, with efficiencies of 43.77%, 42.44%, and 39.95%, respectively. The results indicate that a 5-inch penstock diameter provides the most optimal performance, as it achieves the best balance between head loss, flow distribution, and fluid energy transfer.
The Analysis of Diameter Expansion and Connection Angle Variations Effects In Hyropower Penstock Pipe Bend on Pressure Drop Using Computational Fluid Dynamics Simulation Agung Widodo; Dony Hidayat Al-Janan; Aldias Bahatmaka
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 2 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/wb52b413

Abstract

Pipe bends in hydropower penstock systems effected pressure drop due to changes in fluid flow direction. Pressure drop in piping systems can decrease overall system efficiency. This study aims to analyze the effect of diameter expansion variations (1.25D and 1.5D) and connector angle variations (10o–90o) on pressure drop in 90o pipe bends using Computational Fluid Dynamics (CFD) simulation. The study employed an experimental approach based on ANSYS Fluent 2019 R3 simulation with 13 design variations, an inlet velocity of 7 m/s, water as the fluid, and the k- realizable turbulence model. Simulation results showed that the 1.25D design with a 10o connector angle produced the lowest pressure drop of 1,094.350 Pa, which is 47.7% lower than the standard 1D design with a pressure drop value of 2,090.634 Pa. Design 1.5D with a 90o connector angle yielded the highest pressure drop of 21,355.714 Pa, an increase of 921.51% from the standard 1D design. Increasing the connector angle consistently raised pressure drop in a non-linear pattern across both diameter variations. The 1.25D+10o design proved most optimal by combining effective flow velocity reduction with a gradual geometric transition, thereby minimizing flow separation and turbulence. These findings are expected to contribute to the optimization of hydropower penstock pipe design to improve overall flow system efficiency.
Data-Driven Analysis of Machining Parameters Affecting Surface Roughness (Ra) in CNC Turning of Al6061 Using OLS Method Dimas Ardiansyah Halim; Arbey, S; Rio Evandi; Tosa Susilo; Joko Suparno
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 2 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/e9fjmj14

Abstract

This study aims to analyze the effect of machining parameters on surface roughness (Ra) in the CNC turning process of Aluminum 6061 using the Ordinary Least Squares (OLS) approach. The investigated parameters include cutting speed (v), feed rate (f), nose radius (r), and spindle speed (n). The experimental design was developed using a Central Composite Design (CCD) with five coded levels (+2, +1, 0, ?1, ?2). The machining process was carried out on a CNC GSK 980TDi lathe using CCMT inserts with nose radii of 0.2 mm, 0.4 mm, and 0.8 mm, while the surface roughness was measured using a Mahr Marsurf M300 tester with an accuracy of 0.076 µm. Experimental data were analyzed using the OLS method to determine the most dominant parameters affecting Ra. The results show a coefficient of determination (R²) of 0.932 and an adjusted R² of 0.868, indicating that the regression model provides an excellent level of fit. The nose radius (r) and spindle speed (n) were found to be the most significant factors influencing surface roughness, exhibiting opposite effects. This data-driven approach demonstrates the effectiveness of the OLS method in identifying critical machining parameters in CNC turning processes.
The Influence of Problem Base Learning Model on Improving Psychomotor Abilities of Automotive Engineering Ilham Yuliady; Zulfadli Fadli; Rahmadani; Yogi Dian Alfana; Erik Fernandes
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 1 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/29ry5075

Abstract

Automotive education as a field of vocational education emphasizes the development of psychomotor skills through authentic and industry oriented practical learning. However, practical instruction in automotive workshops is often dominated by conventional teacher centered approaches, resulting in limited student engagement and suboptimal skill development. This study aims to analyze the effect of the Problem Based Learning (PBL) model on improving the psychomotor skills of automotive engineering students in practical learning. A quasi experimental method with a pretest–posttest control group design was employed. The research sample consisted of two classes of automotive engineering students from the 2025 cohort, selected using purposive sampling as the experimental and control groups. Psychomotor skill data were collected using a performance-based assessment instrument covering work procedure accuracy, tool operation skills, occupational safety, and the quality of practical outcomes. Data analysis was conducted using descriptive statistics and an independent t-test with a significance level of a = 0.05. The results indicate that students who participated in Problem Based Learning achieved higher average psychomotor skill scores than those who received conventional instruction. Hypothesis testing confirmed a statistically significant difference between the two groups (t_calculated > t_table). These findings demonstrate that Problem-Based Learning is effective in enhancing students’ psychomotor skills through contextual problem-solving activities, active learning engagement, and meaningful hands-on practice. This study provides empirical evidence supporting the implementation of problem-based instructional models in automotive vocational education and offers practical implications for improving the quality of practice-based learning aligned with industry competency demands.
Analysis of MIG Welding Parameters on the Welding Quality of Apron Feeders in the BINS Workshop Unit of PT. XYZ Aldo Alfattah Sudjono; Nadry Heroza; Randi Purnama Putra; Purwantono
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 1 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/x5p06b82

Abstract

This study examines the effect of MIG Welding parameter variations on the quality of Welded joints in apron feeder components at the BINS Workshop Unit of PT. XYZ. The issue raised is that variations in Welding practices in workshops can cause visual defects and reduce the reliability of heavy-duty components. The objectives of this study are to identify the variations in MIG parameters applied in the field, analyze the quality of Welds based on visual inspection, and determine the most suitable parameters to be adopted for Welding components as a whole. The Method used was a field experiment with a qualitative descriptive approach: Welding was performed on SS400 plate joints (10 mm–6 mm and 4 mm–6 mm) using ER70S-6 wire and CO2 shielding gas with two sets of parameters (wire feed speed 7 m/s vs. 5 m/s), and the results were analyzed through standard visual inspection. The results showed different characteristics: parameters with a higher wire feed produced deeper penetration and wider beads (more suitable for thick plates), while parameters with a lower wire feed provided process stability and a fairly good visual appearance, which was chosen for overall Welding (voltage = 20–22 V; wire feed = 5 m/min). Although the process was generally effective, visual defects such as spatter, porosity/pin hole, cold lap, stop-start, and surface concavity were detected. The study recommends parameter control, machine maintenance, and operator competency improvement to minimize defects and increase joint reliability.
Improving the Competence of Agricultural Machinery Maintenance Training Participants Using the Practical Demonstration Method Wanda Afnison; Purwantono; Dieter Rahmadiawan; Anna Niska Fauza; Donny Fernandez; Elviza Yeni Putri; Ilham Yuliady
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 1 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/s80mh082

Abstract

This training activity was conducted for a group of farmers in Saureinu Village, Mentawai Islands Regency. Based on the team's observation data, we found that many farmers in Saureinu Village still do not understand how to maintain agricultural machinery. As a result, many agricultural machines in Saureinu Village are damaged and cannot be used, thereby reducing farmer productivity. Through this activity, training on agricultural machinery maintenance was provided to the Saureinu village farmer group using the Practical Demonstration method. The Practical Demonstration method was considered appropriate for participants who had diverse backgrounds and no prior understanding of machinery. Based on the team's assessment at the beginning and end of the activity, there was an increase in the participants' knowledge and competence related to the material provided. In the theory session, participants' knowledge increased by 52%, and in the practice session, participants' competence increased by 40%. Participants' mastery of each sub-topic increased by 35-40%. Based on the conversion of scores to assessment categories, this activity was able to improve participants' competencies from poor to good. This improvement is expected to enable the Saureinu Village farmer group to maintain the agricultural machinery they use and maintain stable agricultural productivity.

Page 43 of 44 | Total Record : 437

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