Sigit Tri Wicaksono

Internal geometry effect of structured PLA materials manufactured by dropplet-based 3D printer on its mechanical properties

Rapid Prototyping (RP) technologies, the manufacturing technology with less time consuming including high precission and complicated structure of products, are now become high demanding technologies. Those technologies can be base on top-down or bottom-up approaches. One of the bottom-up approach of RP technology is 3D printing machine. In this research, we have succeed to apply the droplet-based 3D printer to make the structured PLA (Polylactic Acid) materials with different internal geometry structures. The internal geometry used are triangle and honeycomb structure with different size of each symmetry axis of 4.5 mm and 9 mm and the thickness varied of 1 mm and 2 mm as well. The mechanical properties of those structures including tensile and bending stregth are evaluated by using tensile and flexural test respectively. Test results show that the best performance obtained by measuring its tensile and flexural strength is the sampel with triangle geometry of 9 mm geometrical size and 2 mm of thickness. T...

Study on mechanical and physical properties of composite materials with recycled PET as fillers for paving block application

Base on Sidoarjo’s goverment data, there was more than 4000 metric ton perday of waste that has been accumulated during 2016. More than 10 percent from overall waste is plastics. In accordance with the Indonesia government regulation, “Indonesia clean from waste” by 2020 through 3R (Reduce, Reuse and Recycle) program, we have been focusing research on how to reduce the accumulation of the plastics waste in Sidoarjo by processing it become a new product. In this research, we have made the plastic waste of PET bottle as additional fillers or agregates of composite material for construction application as a paving block. The composition of PET plastic used as fillers is vary from 0, 10, 20, 30, 40 and 50% from total volume of agregates. The ratio of cement binder to sands agregate is 1:3. The specimens were characterized its mechanical and physical properties by using flexural testing, compressive testing, density and water absorbance measurement. The results show that the mechanical (flexural and compressive) properties of composite materials is increased significantly by increasing PET fillers up to 20%, however it was decreased when PET content more than 20%. But, both the density and water absobance of specimens are decreased by increasing of PET fillers.Base on Sidoarjo’s goverment data, there was more than 4000 metric ton perday of waste that has been accumulated during 2016. More than 10 percent from overall waste is plastics. In accordance with the Indonesia government regulation, “Indonesia clean from waste” by 2020 through 3R (Reduce, Reuse and Recycle) program, we have been focusing research on how to reduce the accumulation of the plastics waste in Sidoarjo by processing it become a new product. In this research, we have made the plastic waste of PET bottle as additional fillers or agregates of composite material for construction application as a paving block. The composition of PET plastic used as fillers is vary from 0, 10, 20, 30, 40 and 50% from total volume of agregates. The ratio of cement binder to sands agregate is 1:3. The specimens were characterized its mechanical and physical properties by using flexural testing, compressive testing, density and water absorbance measurement. The results show that the mechanical (flexural and compressiv...

Studi Pengaruh Penambahan Binder Thermoplastic LDPE dan PET Terhadap Sifat Mekanik Komposit Partikulat untuk Aplikasi Material Bangunan

Sampah plastik telah lama menjadi permasalahan kota-kota besar, tidak hanya di Indonesia namun juga di dunia. Sampah plastik sangat sulit untuk teruraikan secara alami. Plastik banyak digunakan di seluruh dunia karena memiliki beberapa keunggulan sifat di antaranya adalah ketahanan korosi yang baik, berat yang ringan, flexibel, dan isolator panas dan listrik yang baik. Tujuan penelitian ini adalah membuat material komposit dengan binder thermoplastic dari sampah plastik LDPE dan PET yang biasa ditemukan dalam bungkus makanan dan botol air mineral serta agregrat pasir yang memenuhi kriteria untuk aplikasi material bangunan. Pengujian yang dilakukan meliputi SEM, FTIR, kompresi, bending, absorbability, dan densitas. Penambahan binder thermoplastik cenderung meningkatkan sifat mekanik material komposit. Didapatkan Kekuatan kompresi maksimal sebesar 15,68 MPa pada komposit dengan komposisi binder sebesar 45%. Komposit yang dihasilkan memenuhi kriteria untuk beton ringan struktural dan paving block jenis C dan D.

Precipitation Hardening Formation in Mg6Zn0.5Y Alloy as an Engine Block Application

Magnesium alloys have been widely applied in the automotive world cars or motorcycles and aircraft engines. This is because the weight of the magnesium itself is very lightweight and have high strength. And magnesium alloys have good thermal conductivity, high elastic modulus and good mechanical properties. Magnesium in engineering applications is usually in the mix with elements such as Al, Ag, Mn, Zn, Si, Zr and RE (rare element). Magnesium alloys with zinc are mostly found and used. This research has been carried out precipitation hardening treatment-Mg alloy-0.5Y 6Zn using variable temperature 150oC, 175oC and 200oC with a holding time of 12 hours, 24 hours and 36 hours. The results show microstructure formed is αMg, MgZn, and Mg3Zn6Y (i-Phase). The formation of precipitates during the process of aging raise hardness values up to 75.8 BHN. Aging treatment reduces the thermal resistance of the alloy Mg-6Zn-0.5%Y.

Pengaruh Variasi Komposisi dan Ukuran Filler Serat Tebu Terhadap Morfologi dan Sifat Mekanik Komposit SBR/Serat Tebu

Pengembangan airless tyre sangat penting untuk kendaraan militer untuk meminimalisir resiko fatal dari kegagalan ban konvensional. Sehingga penelitian ini dilakukan untuk menjadi studi awal terkait komposit SBR/Serat Tebu untuk aplikasi flexible spokes untuk airless tyre pada kendaraan militer. Penelitian ini bertujuan untuk mengidentifikasi efek dari penambahan komposisi dan ukuran serat tebu pada sifat mekanik dan morfologi komposit SBR/Serat Tebu. Variasi komposisi yang digunakan adalah 2,5; 5; 7,5; dan 10% dari berat dan variasi ukuran yang digunakan adalah 140, 112, dan 80μ. Komposit dikarakterisasi menggunakan FTIR, morfologi dari komposit diamati menggunakan SEM. Temperatur degradasi, kekerasan, dan kekuatan tarik diamati dengan TGA, durometer hardness shore A, dan mesin tensile . Diamati pula kemampuan serap air dari komposit. Hasil pengujian menunjukkan bahwa penambahan serat tebu hingga 2,5% akan meningkatkan sifat mekanik sementara penambahan lebih lanjut akan menurunkan sifat mekanik dari komposit. Kemudian hasil pengujian juga menunjukkan bahwa penggunaan serat tebu dengan ukuran yang semakin kecil akan semakin meningkatkan sifat mekanik dari komposit.

Deposition of Titanium Aluminium Nitride Thin Layer on High Speed Steel Substrate by Radio Frequency Sputtering

High Speed Steel (HSS) has been widely used in manufacturing industry as one of cutting tool materials because of its good mechanical properties yet with a low price. However, since this material has a low thermal resistance property, it will limit its application when used in dry cutting process. Several methods have been used to improve the cutting performance of HSS in dry cutting. One of them was by growing a thin layer of hard coating on the contact surface of the cutting tool material. In this research, Titanium Aluminium Nitride layer were deposited on AISI M41 High Speed Steel substrate by using Radio Frequency (RF) Sputtering method. The aims of this study were to analyze the effect of variations of Aluminium surface area ratios (10, 20, 30, and 40 %) on the Titanium target and also to analyze the effect of deposition time (15, 30, and 45 minutes) on the composition, phase characterization and morphology of the thin layer that formed. The formation of TiAlN and AlN crystalline compounds were observed by X-Ray Diffraction method. A dense layer with a thickness range from 1.4 to 5.2 µm was observed by using a Scanning Electron Microscopy. It was known that the deposition time affect the thickness and also the roughness of the layer. The topography images by Atomic Force Microscopy showed that the deposition time of 45 minutes produce the finest layer with the surface roughness of 10.8 nm.