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The Effect of Time Variations in the Pure Aluminium Anodization Process Paundra, Fajar; Irfan, Angga; Sidik, M.farhan; Pujiyulianto, Eko; Nurdin, Akhmad
ROTASI Vol 26, No 3 (2024): VOLUME 26, NOMOR 3, JULI 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.3.72-77

Abstract

Aluminium is a white non-ferrous metal and is easily oxidized. In the industrial world, aluminium was chosen because it has the advantages of light density, corrosion resistance, easy fabrication (forged), high thermal and electrical conductivity. However, aluminium also has disadvantages, namely having a low hardness value when compared to steel. Pure aluminum hardness is only around 50 VHN. Therefore anodizing is expected to improve the hardness value of aluminium. This study aims to determine the effect of time variation on the value of changes in mass, hardness, oxide layer thickness, and microstructure. This study used aluminium 1100 with a time variation of 60, 70, 80, and 90 minutes, a concentration of H2SO4 of 10%, a current density of 6 A and a voltage of 20 V. The results of the study using a time variation of 60, 70, 80 and 90 minutes obtained the change in value the smallest mass occurred at 60 minutes of 0.4 g and the largest occurred at 90 minutes of 1.09 g. The smallest hardness value occurred at 60 minutes at 72.8 VHN and the highest occurred at 90 minutes at 86.7 VHN. The lowest layer thickness value occurred at 60 minutes of 7.96 µm and the highest occurred at 90 minutes of 10.79 µm
PENGARUH PENGGUNAAN MAGNET EKSTERNAL DAN VARIASI ARUS PADA PENGELASAN TIG TERHADAP STRUKTUR MIKRO KEKERASAN DAN KEKUATAN TARIK BAJA KARBON RENDAH Paundra, Fajar; Yudanta, Faturrizky Rakha; Muhyi, Abdul; Pujiyulianto, Eko; Syanur, Farid Nanda; Darsono, Febri Budi
SINERGI POLMED: Jurnal Ilmiah Teknik Mesin Vol. 5 No. 2 (2024): Edisi Agustus
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/sinergipolmed.v5i2.1561

Abstract

Medan magnet eksternal dapat meningkatkan kualitas dari hasil pengelasan TIG. Penelitian ini bertujuan untuk mengetahui pengaruh medan magnet eksternal dalam proses pengelasan TIG. Material yang digunakan dalam penelitian ini adalah baja SS400. Proses pengelasan menggunakan TIG (Tungsten Inert Gas)  dengan variasi arus 70 A, 80 A, 90 A, dan 100 A serta menggunakan tambahan 2 magnet eksternal jenis Neodymium. Pengujian hasil pengelasan berupa struktur makro, mikro, uji kekerasan vickers dan uji tarik. Hasil pengujian struktur makro menunjukan beberapa cacat hasil pengelasan seperti Porositas, Incomplete Penetration, Underfill, dan Distorsi. Sedangkan hasil pengujian struktur mikro menunjukan pada base metal terdapat struktur jenis Ferrite dan Pearlite. Bagian HAZ terdapat struktur jenis Ferrite, Pearlite, dan Martensite. Hasil pengujian tarik paling tinggi terdapat pada sambungan pengelasan TIG tanpa menggunakan magnet dengan arus 100 A yaitu sebesar 368,234 MPa. Hasil pengujian kekerasan paling tinggi terdapat pada sambungan pengelasan TIG menggunakan magnet dengan arus 100 A yaitu sebesar 176,712 HVN. Penggunaan magnet eksternal dapat menghasilkan penetrasi besar saat proses pengelasan dan mengahasilkan sambungan las yang baik. Sebaliknya, hal tersebut dapat berakibat buruk terhadap hasil pengelasan jika jarak busur listrik dengan material tidak tepat, dan torch tidak bergerak sesuai pada jalur pengelasan.
Analisis Penggunaan Limbah Resin Coated Sand sebagai Substitusi pada Cetakan Greensand Terhadap Karakteristik Pengecoran Logam Aluminium Nurdin, Akhmad; N, Muhammad Dwi; S, Ardi Bagus; Paundra, Fajar; Muhyi, Abdul; Pujiyulianto, Ekko; K, Putra Andi; N, Fajar Perdana; S, Farid Nanda; D, Febri Budi
Jurnal Rekayasa Energi dan Mekanika Vol 4, No 1 (2024): JREM
Publisher : Institut Teknologi Nasional, Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26760/JREM.v4i1.25

Abstract

Resin Coated Sand atau RCS  salah satu jenis cetakan yang digunakan untuk proses pengecoran logam dan menghasilkan limbah yang mengandung resin. Sebagian besar limbah RCS  masih dapat  didaur ulang, karena masih mengandung pasir silika dan berukuran lebih kecil dibandingkan pasir silika untuk cetakan greensand. Cetakan greensand terdiri dari pasir silika dengan pengikat merupakan cetakan pasir yang sering digunakan pada industri pengecoran logam. Penelitian ini bertujuan untuk mengetahui bagaimana pengaruh penambahan limbah pasir RCS pada cetakan greensand terhadap karakteristik kekerasan dan struktur mikro pada peleburan ulang aluminium-silikon. Penelitian ini dilaksanakan untuk mendapatkan data pada komposisi limbah cetakan pasir RCS dengan presentase 0%, 20%, dan 40% terhadap pasir baru grendsand, sedangkan material logam aluminium yang digunakan pada penelitian ini mengunakan limbah sepatu rem tromol sepeda motor. Hasil pengecoran logam didapat spesimen logam aluminium yang diuji kekerasan dan metalografi. Pada penambahan RCS 20% menunjukkan nilai kekerasan yang cenderung sama pada penambahan 0%, namun nilai kekerasan akan naik 2,4 kali pada penambahan RCS 40%. Berdasarkan pengujian metalografi penambahan RCS 40% menunjukkan struktur fasa Si yang cenderung lebih meluas dibandingkan pada penambahan 0% dan 20%.
Simulation Study of Pin-Type Heatsinks on Convection Heat Transfer Characteristics in Electronic Devices Chaniago, Noverto Zhorif; Alfian, Devia Gahana Cindi; Syaukani, Muhammad; Pujiyulianto, Eko; Nurullah, Fajar Perdana; Silitonga, Dicky Januarizky
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.47-53

Abstract

Electronic components are components that require an optimal design in order to provide good heat release performance. The heat sink component is a relevant solution to help cool an electronic component by flowing heat energy into the environment either naturally or forcibly with the help of a fan. The purpose of this study is to determine the effect of material type on heat sink temperature distribution, determine the phenomenon of velocity boundary layer and thermal boundary layer that occurs in each heat sink variation, determine the effect of design shape and pin arrangement on pressure drop, determine the best design according to the final results of the study. This research uses 6 variations of design shape, 2 variations of arrangement (inline and staggered), and 3 types of materials (Aluminum, Copper, and Iron). The method used in this research is a simulation method with three stages of process, namely, pre processing, processing, and post processing. The results showed that copper material is the best in conducting heat with a temperature drop of 98.5% from the base temperature. The inline arrangement obtained a lower pressure drop than the staggered arrangement and the best design was obtained by fillet square perforation with an inline arrangement.
Pengembangan Mesin Pencacah Plastik Skala Rumah Tangga dari Desain Precious Plastic Project Saefudin, Deny Bayu; Ikaningsih, Manty Aldilani; Karmiati, Besse Titing; Nurdini, Lulu; Pujiyulianto, Eko
Jurnal Pendidikan dan Teknologi Indonesia Vol 5 No 10 (2025): JPTI - Oktober 2025
Publisher : CV Infinite Corporation

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52436/1.jpti.1416

Abstract

Sampah plastik rumah tangga terus meningkat, namun sistem pengelolaan daur ulang masih terbatas dan belum efisien. Kondisi ini menyebabkan akumulasi sampah plastik yang berdampak negatif terhadap lingkungan dan kesehatan masyarakat. Penelitian ini bertujuan untuk mengembangkan mesin pencacah plastik skala rumah tangga yang terjangkau, dan mudah dioperasikan sebagai solusi teknologi tepat guna dalam pengelolaan sampah. Desain mesin ini dikembangkan berdasarkan rancangan acuan dari Precious Plastic Project yang digagas oleh One Army, dan dimodifikasi sesuai ketersediaan material lokal dan kebutuhan pengguna di Indonesia. Tahapan pengembangan rancangan dimulai dari studi literatur rancangan mesin pencacah plastik, modifikasi rancangan dengan bantuan perangkat lunak Autodesk Inventor, proses fabrikasi dan perakitan komponen, serta uji fungsi dan kinerja mesin. Mesin ini terdiri dari rangka baja ringan berbentuk square tube berukuran 30 x 30 x 1 mm, sistem penggerak motor gear 180 W dengan speed controller, shredder box bertipe single shaft dengan cutter bermaterial Hardox 450, serta hopper dari plat baja. Hasil pengujian menunjukkan mesin berfungsi optimal, mampu mereduksi plastik menjadi cacahan berukuran sekitar 1 cm dengan kapasitas 5-8 kg/jam. Pengembangan ini menunjukkan efisiensi energi yang baik dan struktur yang kuat, menjadikannya solusi praktis dan ramah lingkungan untuk mendukung pengelolaan sampah plastik di lingkup rumah tangga.
Analysis of Hardness Test and Microstructure Test of R.54 Type Railway Rail with Variations in Heat Treatment Cooling Media Oktavia, Amelia; Tabitha, Adinda Kanaya; Drajat, Bambang; Pujiyulianto, Eko
Journal of Engineering and Scientific Research Vol. 7 No. 2 (2025)
Publisher : Faculty of Engineering, Universitas Lampung Jl. Soemantri Brojonegoro No.1 Bandar Lampung, Indonesia 35141

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jesr.v7i2.175

Abstract

Rail steel R.54 is a steel that is included in high carbon steel. Rail steel R.54 has a carbon element of 0.60-0.80% allowing the hardening process to be carried out with appropriate heat treatment . This type of research is an experimental laboratory study. The study aims to determine the effect of variations in cooling media on the observation of microstructure and hardness values in the hardening process of rail steel R.54. The Vickers method with a load of 500 gf is one of the important aspects in hardness testing. The results showed that the hardness value without heat treatment was 383.93 HV and the hardness value after heat treatment with three variations of cooling media, namely soapy water of 669.13 HV, 35% table salt (NaCl) of 689.14 HV, and new oil of 835.50 HV. The three cooling media can be concluded that the highest level of steel hardness is achieved in specimens that are hardened and cooled with new oil cooling media. The viscosity of new oil affects the hardness level of R-54 rail steel. The hardness level of R-54 rail steel will increase along with the increasing viscosity of the oil that is inserted into the cooling medium of R-54 rail steel after the quenching process. The results of observations of the microstructure of R-54 rail steel samples show that there is a phase change without heat treatment that is formed is ferrite and pearlite to form ferrite , austenite and martensite phases due to the heating process of austenite which is cooled rapidly in the cooling medium.
Modified Zeolite-Based Composite as Urea Slow-Release Fertilizer – A Mini Review Siti Mahmudha; Taranipa Marfitania; Muhammad Idris; Sulwiyatul Kamariyah Sani; Pina Budiarti Pratiwi; Eko Pujiyulianto
Sustainable in Energy Science and Technology Vol. 1 No. 1 (2025): Sustainable in Energy and Science Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i1.2579

Abstract

Urea is the most commonly used nitrogen fertilizer in agriculture due to its high nitrogen content and low cost. However, its efficiency is often below 50% because of nitrogen losses through leaching, volatilization, and surface runoff. To reduce these losses and improve fertilizer efficiency, slow-release fertilizers (SRFs) using modified zeolite-based composites have been developed. Zeolite is a porous aluminosilicate mineral with excellent ion exchange and adsorption properties, making it a good carrier for urea. However, natural zeolite has limitations, such as impurities and low surface area, which can be improved through modification techniques like acid–base treatments (dealumination and desilication), surfactant modification, and combination with organic or inorganic materials. These modifications improve pore size, surface area, and nutrient-holding capacity, allowing for a slower and more controlled release of nitrogen. This mini review discusses recent studies on the preparation, characterization, and performance of modified zeolite composites for urea delivery, showing their potential to reduce environmental impact and increase nutrient use efficiency in agriculture.