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Journal : REKAYASA

Analisis Material Efoxy EF150K Terhadap Temperatur dan Kelembaman Tinggi Pada Komponen Charger Mobil Listrik Shieddieque, Apang Djafar; Abdulah, Amri; Rajab, Dede Ardi; Jatira, Jatira; Rag, Yoon Jung; Kil, Sohn Chang; Kurnia, Tata
Rekayasa Vol 14, No 2: Agustus 2021
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v14i2.10244

Abstract

Electric cars have now been made and developed by famous car manufacturers outside of Indonesia. Of course electric cars have batteries that must be recharge. Inside the electric car charger there is a controller which is one of the components, which is an epoxy coated capacitor. The faster the charger, the higher the temperature will be, to deal with this problem, it is necessary to increase the performance of the capacitor to increase the temperature and humidity resistance. Then from this explanation the researchers will test the EF150K epoxy coating on the Disc Ceramic Capacitor (DCC), by using epoxy coating thickness testing by using 3 samples the results obtained are on average 0.8 mm, Pressure Cycle Test (PCT) using 20 samples with  conditions temp: 121 °C, p: 2 bar for 48 hour, obtained average capacities and insulance resistance before PCT testing C: 2155,4pF, IR: 141540Ω and after C: 2238,2 pF, IR: 147140 Ω, and humidity test using 20 sample with condition 95% RH, temp: 40°C for 504h obtained average capacities and insulance resistance before humidity test C: 2.157,89 pF, IR: 119560 Ω and after C: 2.233,63 pF, IR: 123160 Ω. The use of EF150K epoxy is very well used as a DCC capacitor coating, because the coating is resistant to temperatures up to 121 ° C with a pressure of 2 bar, and withstands temperatures up to 40 °C with 95% RH. 
Pengaruh Variasi Campuran Bentonit Terhadap Karakteristik Pasir Cetak Untuk Proses Sand Casting Apang Djafar Shieddieque; Ismail Putra Nugraha; Mochammad Iqbal Zaenal Muttahar; Ghany Heryana
Rekayasa Vol 15, No 3: Desember 2022
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v15i3.16194

Abstract

The casting process is widely used because it has the advantage of being able to make products with small dimensions to very large dimensions, the use of materials is more efficient, the casting products can be directly used. However, in the casting process, the main triggers for the formation of defects are the nature of the mold, low permeability, low molding compressive strength, low sintering point, unsuitable sand grain distribution, so research is needed to obtain the right type of molding sand as a sand mold in metal casting. The only type of additive is bentonite. Bentonite can absorb water and expands between 8-15 times and remains dispersed in water for a certain period of time. This study aims to examine the effect of a mixture of variations of local bentonite and Australian bentonite on the characteristics of the molding sand for the sand casting process. The tests carried out are in the form of size distribution testing, X-Ray Diffraction, water content testing, compressive strength, and permeability measurements. Bentonite was varied into 5 variations of the mixture with a difference of 20% in each mixture. The results of the large size distribution of silica sand grains were 37.6 GFN. The results of XRD testing of local bentonite showed a higher content of calcium compounds and Australian bentonite contained higher sodium compounds. The largest water content test value is 5.825%. The largest compressive strength test value is 2.7 Kgf /cm2.
Pengaruh Variasi Holding Time pada Proses Single Stage Aging Terhadap Kekerasan dan Mikrostruktur pada Material Paduan Al-Si-Cu-Fe Shieddieque, Apang Djafar; Kuswandi, Rendi
Rekayasa Vol 18, No 1: April 2025
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v18i1.26678

Abstract

The Al-Si-Cu aluminum alloy is the most commonly used alloy for household appliances, aircraft materials, automotive, marine vessels, construction, and more. However, cast aluminum alloys still exhibit low mechanical properties, necessitating additional processes to enhance their strength. One method of strengthening aluminum is by varying the composition and/or heat treatment process. The aim of this research is to investigate the effect of aging time variation on the microstructure and hardness of the Al-Si-Cu-Fe alloy. The heat treatment processes conducted in this study include solid solution treatment (T=540°C and t=5 hours) and various single-stage aging treatments (T=155°C and t=4, 5, and 6 hours). Mechanical properties of the aluminum alloy were evaluated through metallographic observations and Brinell hardness testing. Microstructural observations indicate changes in the Silicon microstructure from the As cast sample, which exhibits dendrites, to the formation of AlSi and AlFeSi phases after aging treatment. With longer aging treatments, larger and more dispersed precipitate grains are formed. The variation in holding time has different effects on hardness, with the highest hardness obtained at a holding time of 4 hours during artificial aging, resulting in 71.57 BHN. However, increasing the holding time tends to decrease hardness due to the growth of larger precipitate phases.