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SMALL-HOLE DRILLING USING DIE SINKER ELECTRICAL DISCHARGE MACHINE Firmanto, Hudiyo; Winarto, Felixtianus Eko Wismo
ROTOR Vol 7, No 1 (2014)
Publisher : ROTOR

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (377.948 KB)

Banyak kesulitan dihadapi pada pemesinan lubang kecil. Terutama jika prosesnya dilakukan dengan proses drilling mekanik. Untuk mengatasi kendala yang dihadapi, proses pemesinan non-tradisional seringkali diterapkan. Tulisan ini melaporkan hasil studi pemesinan lubang kecil (diameter kurang dari 1 mm) menggunakan EDM die sinker. Lubang dibuat pada aluminium dengan ketebalan 3 mm. Kawat tembaga berdiameter kurang dari 1 mm dipergunakan sebagai elektroda. Untuk menghindari keausan elektroda yang berlebihan, pemesinan dilakukan dengan menggunakan parameter yang menghasilkan energi rendah. Pemilihan parameter ini juga dimaksudkan untuk mendapatkan kualitas lubang yang baik. Pengamatan dilakukan terhadap kualitas lubang yang dihasilkan. Selain itu studi juga dilakukan pada pengaruh parameter pemesinan terhadap keausan elektroda dan waktu pemesinan. Hasil studi menunjukkan bahwa lubang dengan diameter kurang dari 1 mm berhasil dibuat dengan mesin EDM die sinker. Waktu yang diperlukan untuk pemesinan berkisar antara 5 â 6 menit. Lubang yang dihasilkan memiliki kebulatan yang relative baik dan permukaan yang tajam. Peningkatan energi pemesinan menambah keausan elektroda dan memperpanjang waktu pemesinan. Â Keywords: EDM, small hole, drilling, electrode wear

Thermal Energy Storage Optimization in Shopping Center Buildings Biyanto, Totok R.; Alhikami, Akhmad F.; Nugroho, Gunawan; Hantoro, Ridho; Bayuaji, Ridho; Firmanto, Hudiyo; Waluyo, Joko; Sonhaji, Agus Imam
Journal of Engineering and Technological Sciences Vol 47, No 5 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

In this research, cooling system optimization using thermal energy storage (TES) in shopping center buildings was investigated. Cooling systems in commercial buildings account for up to 50% of their total energy consumption. This incurs high electricity costs related to the tariffs determined by the Indonesian government with the price during peak hours up to twice higher than during off-peak hours. Considering the problem, shifting the use of electrical load away from peak hours is desirable. This may be achieved by using a cooling system with TES. In a TES system, a chiller produces cold water to provide the required cooling load and saves it to a storage tank. Heat loss in the storage tank has to be considered because greater heat loss requires additional chiller capacity and investment costs. Optimization of the cooling system was done by minimizing the combination of chiller capacity, cooling load and heat loss using simplex linear programming. The results showed that up to 20% electricity cost savings can be achieved for a standalone shopping center building.

Thermal Energy Storage Optimization in Shopping Center Buildings Totok R. Biyanto; Akhmad F. Alhikami; Gunawan Nugroho; Ridho Hantoro; Ridho Bayuaji; Hudiyo Firmanto; Joko Waluyo; Agus Imam Sonhaji
Journal of Engineering and Technological Sciences Vol. 47 No. 5 (2015)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2015.47.5.7

In this research, cooling system optimization using thermal energy storage (TES) in shopping center buildings was investigated. Cooling systems in commercial buildings account for up to 50% of their total energy consumption. This incurs high electricity costs related to the tariffs determined by the Indonesian government with the price during peak hours up to twice higher than during off-peak hours. Considering the problem, shifting the use of electrical load away from peak hours is desirable. This may be achieved by using a cooling system with TES. In a TES system, a chiller produces cold water to provide the required cooling load and saves it to a storage tank. Heat loss in the storage tank has to be considered because greater heat loss requires additional chiller capacity and investment costs. Optimization of the cooling system was done by minimizing the combination of chiller capacity, cooling load and heat loss using simplex linear programming. The results showed that up to 20% electricity cost savings can be achieved for a standalone shopping center building.

SURFACE QUALITY AND CORROSION RESISTANCE OF 316L STAINLESS STEEL ELECTROPOLISHED USING PHOSPHORIC – SULFURIC ACIDS Firmanto, Hudiyo; Arief, Budhyantoro
Jurnal Rekayasa Mesin Vol. 14 No. 3 (2023)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/jrm.v14i3.1333

Electropolishing is an electrochemical surface finishing technique. It is commonly applied to equipment that requires a gleaming finish. This surface property is frequently required in 316L stainless steel (SS) medical implants. Electropolishing removes a thin layer from the metal's surface through electrochemical processes. This results in a very clean, smooth, and bright metal surface. The process parameters, such as electrolyte solution, electrical current, and electropolishing time, influence surface roughness and glossiness. The dissolution of metallic ions during the process may also affect the corrosion resistance of the treated material in addition to producing a shiny surface. This study investigated the surface glossiness, surface roughness, and corrosion of electropolished 316L SS. Electropolishing experiments on 316 SS were carried out using various H3PO4 (50%) and H2SO4 (32%) electrolyte solution compositions. The influences of electrolyte solution composition, electric current, and electropolishing time were studied. The results showed that increasing the H2SO4 content of the mixture and electropolishing the 316L SS for a longer period of time improved the surface roughness and glossiness. Under 10 Amp electric currents, the best surface glossiness was discovered. A corrosion test revealed that the electropolishing produced a Cr and Ni-rich layer that improved the corrosion resistance of the samples.

SURFACE QUALITY AND CORROSION RESISTANCE OF 316L STAINLESS STEEL ELECTROPOLISHED USING PHOSPHORIC – SULFURIC ACIDS Firmanto, Hudiyo; Arief, Budhyantoro
Jurnal Rekayasa Mesin Vol. 14 No. 3 (2023)
Publisher : Jurusan Teknik Mesin, Fakultas Teknik, Universitas Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/jrm.v14i3.1333

Electropolishing is an electrochemical surface finishing technique. It is commonly applied to equipment that requires a gleaming finish. This surface property is frequently required in 316L stainless steel (SS) medical implants. Electropolishing removes a thin layer from the metal's surface through electrochemical processes. This results in a very clean, smooth, and bright metal surface. The process parameters, such as electrolyte solution, electrical current, and electropolishing time, influence surface roughness and glossiness. The dissolution of metallic ions during the process may also affect the corrosion resistance of the treated material in addition to producing a shiny surface. This study investigated the surface glossiness, surface roughness, and corrosion of electropolished 316L SS. Electropolishing experiments on 316 SS were carried out using various H3PO4 (50%) and H2SO4 (32%) electrolyte solution compositions. The influences of electrolyte solution composition, electric current, and electropolishing time were studied. The results showed that increasing the H2SO4 content of the mixture and electropolishing the 316L SS for a longer period of time improved the surface roughness and glossiness. Under 10 Amp electric currents, the best surface glossiness was discovered. A corrosion test revealed that the electropolishing produced a Cr and Ni-rich layer that improved the corrosion resistance of the samples.

Rotary friction welding of 304 stainless steel: parametric study, mechanical properties, and microstructure of the joint Firmanto, Hudiyo; Candra, Susila; Hadiyat, Mochammad Arbi
Jurnal Polimesin Vol 22, No 2 (2024): April
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v22i2.4978

In the rotary friction welding process, the selection of process parameters affects the friction, heat generation, and joint formation. These factors collectively cause microstructural changes that determine the mechanical properties of the joint. Therefore, the process parameters, microstructure, and mechanical properties were interconnected during rotary friction welding. This study examined the influence of process parameters on their correlation with microstructure and mechanical properties in the rotary friction welding of 304 SS. A 3×4 full factorial experimental design was used to evaluate the effects of the process parameters on the microstructure and strength of 304 SS joints produced through rotary friction welding. An accurate evaluation of joint strength was performed using the notch tensile test technique. The joint with the highest strength was achieved by applying a combination of friction pressure and friction time at 55 bars and 3 seconds, respectively, resulting in a welding efficiency of 103.6%. A very low friction time (i.e., 5 s) produced a weak joint, which should be avoided. The welding process created three distinct structural zones in the joint: a joint structure finer than the parent metal structure, a partially deformed structure, and a heat-affected zone with deformation. Hardness tests of the joints showed a high hardness in the deformed structure. The formed structure contributes to the resulting joint strength.

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