JURNAL MESIN TEKNOLOGI
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Analysis of Corrosion Rate Al 7075 Using Seawater and Rainwater Media Using the K2CRO4
Full text linkAluminum is one of the most widely used materials today due to several advantages, including its lightweight nature, relatively high tensile strength, good formability, corrosion resistance, and non-magnetic properties, making it a preferred choice in industries such as aerospace. However, metals, including 7075 aluminum alloy commonly used in the aerospace industry, are still susceptible to corrosion in corrosive environments. One effective method to control corrosion is the use of inhibitors. An inhibitor is a chemical substance that, when added in small amounts to a corrosive environment, can effectively slow down or reduce the corrosion rate. This study investigates the corrosion rate using the potentiodynamic polarization method (Tafel plot) in seawater from Parangtritis Beach and rainwater from Yogyakarta City. The inorganic inhibitor used in this research is K₂CrO₄ with a concentration of 0.3%. The results show that the corrosion rate in seawater without inhibitors (pH 7.34) is 0.027799 mm/yr, while with inhibitors (pH 7.50), it decreases to 0.0053243 mm/yr. Similarly, the corrosion rate in rainwater without inhibitors (pH 6.66) is 0.0021987 mm/yr, while with inhibitors (pH 7.74), it reduces to 0.0017807 mm/yr. These findings demonstrate the effectiveness of K₂CrO₄ inhibitors in minimizing corrosion rates in both seawater and rainwater environments
Optimisation of Air-water Harvester Machine Performance With Variations of Inlet Air Flow Velocities
Full text linkIn the dry season, some parts of Indonesia experience drought and clean water crisis which results in scarcity and difficulty in drinking water. One way to overcome this problem is to present a water-producing device from air called a water harvester machine. The purpose of this study was to examine the effect of the inlet air velocity of 4 m/s, 5 m/s, and 6 m/s on the mass of water produced and the rate of heat transfer. This study was conducted experimentally with R134a refrigerant working fluid, and a 1 PK rotary compressor and centrifugal fan. The results showed that the highest water mass, which was 5.99 kg, was obtained at an air velocity of 6 m/s. The highest heat transfer rate, which was 2080.2 W, was also obtained at a speed of 6 m/s. This can be caused by the high inlet air velocity, the inlet air mass flow rate is also high so that the water vapor content that enters is greater. As a result, the mass of water produced is greater and the rate of heat transfer that occurs is also greater
Analysis of Boiler Efficiency and NPHR With the Use of Sootblower in a 315 MW Coal-fired Power Plant
Full text linkIn the power generation sector, particularly in Indonesia, coal-fired power plants remain a key source of electricity. The Lontar Extension Coal-Fired Steam Power Plant (PLTU) (1x315 MW) is a significant facility that plays a critical role in ensuring a stable electricity supply to the Jakarta area and its surroundings. One of the major operational challenges faced by the plant is managing the ash produced during coal combustion, which leads to slagging and fouling on boiler tube surfaces. These phenomena impair heat transfer efficiency and increase fuel consumption. Given the growing emphasis on operational efficiency and sustainability in the power generation industry, addressing these challenges is of paramount importance. In this research, we conduct a comprehensive analysis of key performance parameters, such as Net Plant Heat Rate (NPHR) and boiler efficiency, at the Lontar Extension PLTU. A particular focus is placed on the use of soot blowers in the Heat Recovery Area (HRA) to mitigate slagging and fouling issues. This study offers unique insights by quantifying the benefits of soot blower operation, which resulted in a 0.71% increase in boiler efficiency and a 33.91 kcal/kWh decrease in NPHR at 100% load, and a 0.63% increase in boiler efficiency and 47.16 kcal/kWh reduction in NPHR at 50% load. Additionally, the soot blowers contributed to increased net power output and reduced coal consumption, highlighting the innovation in boiler cleaning techniques and their significant impact on fuel efficiency
Design and Manufacture of Automatic Collet Clamping Systems for Sprocket-CAM Handling on CNC Lathes
Full text linkA proper clamping system reduces clamping time, enhances process repeatability, and increases flexibility in product replacement, significantly improving a company's competitiveness in terms of time and cost. The chamfering process for the KN-00XX series sprocket-cam product at PT. Toshin Prima Fine Blanking faced challenges due to the absence of a clamping device capable of quickly, securely, and automatically accommodating the contour clamping process while ensuring a long service life. To address this, optimizing existing spare parts, such as collets and pneumatic mechanisms, was essential to minimize manufacturing costs. This research aimed to design and evaluate a chuck tool that reduces product installation time and optimizes component stock to lower manufacturing costs. The study applied the VDI 2221-QFD method, where VDI 2221 identified functional requirements and user needs, while QFD assessed these needs and prioritized them for cost-effective design. Finite Element Analysis (FEA) was used to evaluate the design's strength and performance. The resulting pneumatic collet clamping design showed an actual von Mises stress value of 1,044,029 kN/m², safely below the maximum allowable value of 1,080,000 kN/m². FEA analysis indicated a collet displacement of 0.37 mm, close to the actual measured value of 0.42 mm, meeting clamping requirements. The estimated manufacturing cost of the pneumatic collet clamping system was Rp. 1,472,769. Actual trials demonstrated an average cycle time of 9.8 seconds, confirming that the pneumatic collet clamping design is safe, efficient, and fulfills specified requirements
Repair of Wire Feeder Gears in a 1300-Watt MIG Welding Machine Using Reverse Engineering Technology
No full textMaterial failure is a common occurrence in components subjected to continuous loads, often due to fatigue. In the MIG 1300-watt welding machine, the wire feeder gear transmission process continuously distributes energy, leading to eventual material failure. This failure disrupts the transmission of rotation to the feeder shaft, causing the wire exiting the torch to slip. To address this issue, reverse engineering technology is applied using computer-aided design (CAD), finite element analysis (FEA) assisted by computer-aided engineering (CAE), and computer-aided manufacturing (CAM), culminating in the production of prototypes with 3D printing technology. This research aims to repair the wire feeder gears by leveraging reverse engineering technology, which includes redrawing the gears and implementing developmental modifications using CAD/CAM tools. These modifications are then analyzed through FEA with CAE assistance, and the final prototype is produced using an Anet A8 V2 3D printer with Poly Lactic Acid (PLA) material
Analysis of the Use of Fine Filters on Lubricating Oil Content With Contaminant Tests in Diesel Engines
Full text linkLubricating oil is a critical component in the operation of diesel engines, functioning to reduce wear and dissipate heat generated by friction in moving engine components. Compared to gasoline engines, diesel engines produce higher levels of carbon during combustion, necessitating the use of lubricating oil filters to remove combustion residues. Additionally, fine filters are employed to minimize contaminants present in the lubricating oil. This study aims to analyze the contaminant levels in different states of lubricating oil: new, unused oil; oil used for 500 hours without a fine filter; oil used for 500 hours with a CJC fine filter; and oil used for 1,336.5 hours with a CJC fine filter. The testing methods employed were ASTM D5185-18 and ASTM E2412-10, with all analyses conducted at the PT Petrolab Services Laboratory. The results demonstrate that the use of a CJC fine filter significantly reduces contaminants, with sodium levels at 1 ppm, silicon levels at 7 ppm, and Fuel Dilution, Water Content, and Glycol levels consistently at 0%
Characterization of Catalytic Converter Made from Chrome-Plated Copper Plate Catalyst for Gasoline Motors
Full text linkThis study characterizes copper (Cu) and chrome-plated copper (Cu-Cr) catalyst materials used in catalytic converters for gasoline engines. The objective is to investigate morphological and compositional changes resulting from exhaust gas emission testing. Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDX) was employed for microstructural analysis of the catalyst materials. The research examines morphological changes in Cu and Cu-Cr catalysts before and after exhaust gas emission testing, along with elemental composition alterations. Results indicate that exhaust gas exposure significantly alters the morphology and composition of both catalyst types. Morphologically, Cu catalyst particles originally flat with fine grains exhibited rougher, uneven surfaces with random grain formations and porosity post-testing. Similarly, Cu-Cr catalyst surfaces transformed from smooth to uneven, marked by darkened spots. Compositionally, Cu catalysts initially consisting of five elements (Cu 82.92%, O 5.96%, C 10.22%, Cl 0.60%, Si 0.29%) changed to include eight elements (Cu 70.65%, O 12.89%, C 12.85%, Cl 0.66%, Si 0.27%, N 1.74%, Al 0.27%, S 0.67%). Cu-Cr catalysts initially composed of three elements (Ni 87.65%, Cr 10.50%, C 1.85%) evolved to five elements (Ni 86.01%, Cr 6.56%, O 5.70%, O 1.42%, S 0.71%). These findings underscore the transformative effects of exhaust gas exposure on catalyst materials, influencing both their morphology and elemental composition, crucial for enhancing catalytic converter performance and durability in automotive applications
Analysis of the Performance of Moisture Reduction Rate in a Horizontal Mill Type Coffee Dryer Using a Suction Blower
Full text linkCoffee, originating in the 9th century Ethiopia and later expanding across North Africa and tropical regions globally, remains a crucial commodity. Indonesia, recognized for its robust coffee industry, ranks third worldwide in production, contributing 8% of the global supply. However, the drying process poses challenges to Indonesian farmers due to traditional methods and variable weather conditions. This research aims to evaluate a coffee dryer utilizing forced convection with a suction blower to optimize drying parameters for coffee beans. The study employs a horizontal mill dryer with a heated drum for drying experiments. Results demonstrate that the dryer effectively reduces the moisture content of post-harvest coffee cherries to 2%. In the initial test, 20 kg of coffee dried over 7.5 hours at 75℃ decreased from 61.66% to 5.3% moisture, while a subsequent test with 17 kg dried over 4 hours reduced from 36% to 2% moisture content. The findings conclude that the suction blower-equipped dryer meets Indonesian National Standards (SNI), achieving the requisite 12% moisture content for post-harvest coffee
Thermal Efficiency Analysis on Box Dryer Equipment in the Chemical Industry
Full text linkBox dryers are widely utilized in the chemical processing, food, and agricultural industries for drying purposes. The efficiency of these dryers significantly impacts energy utilization. Low thermal efficiency suggests inefficient heat utilization compared to the energy required for drying. Therefore, analyzing thermal efficiency is crucial to optimize energy usage, enhance drying effectiveness, and identify avenues for improvement. This study employs a direct method to assess the thermal efficiency of a box dryer. Data from observations, operational parameters, and literature form the basis for calculating thermal efficiency. Results indicate thermal efficiency ranging from 89.00% to 92.00%, with a drying feed mass rate of 77–91 kg/hour over six hours of operation. These findings classify the box dryer equipment as highly efficient. The industry maintains this efficiency through periodic maintenance schedules and optimization of drying conditions. This research provides a foundational analysis of box dryer performance, aiming to streamline the drying process and minimize energy consumption. The outcomes contribute to ongoing efforts in industrial sectors to enhance operational sustainability and economic viability
Enhanced Performance of the Gorlov Hydrokinetic Turbine through Blade Profile Modification
Full text linkThe Gorlov turbine is a widely used hydrokinetic turbine for household-scale hydroelectric power generation, known for its superior performance compared to other turbine types. Despite its high efficiency, the Gorlov turbine has a significant drawback: it cannot operate effectively at low water speeds due to its blade design, which relies solely on lift force. This study aims to address this limitation by modifying the blade profile to harness drag force in addition to lift force. The modified blade profile retains the original crescent shape while enhancing its design. For data validation, two models were created: the conventional Gorlov turbine and a modified version. Laboratory-scale tests were conducted using a water pump to simulate flow in an artificial channel, with water speeds ranging from 0.185 m/s to 0.225 m/s. Correlation regression analysis was employed to evaluate the experimental results and strengthen the reliability of the findings. The results indicate a correlation between changes in water flow speed and increases in turbine rotation, turbine torque, torque coefficient, and power coefficient. Specifically, the conventional Gorlov turbine exhibited an average torque of 0.014 Nm, a torque coefficient of 0.0209, and a power coefficient of 0.32. In contrast, the modified Gorlov turbine demonstrated an average torque of 0.016 Nm, a torque coefficient of 0.239, and a power coefficient of 0.308