Found 4 Documents

Determination of Operation Condition and Product Dimension Accuracy Optimization of Filament Deposition Modelling on Layer Manufacturing Application Widyanto, Slamet; Tontowi, Alva Edy; Jamasri, Jamasri; Rochardjo, Heru Santoso Budi
Makara Journal of Technology Vol 10, No 2 (2006)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (269.348 KB) | DOI: 10.7454/mst.v10i2.117


Layer manufacturing process has proven as a process that can produce a high complexity mechanical part. Now, Improvement of LM methods continuously conduct that is aimed to increase precessions and efficiency of these processes. Pressure filament deposition modelling is a form of layer manufacturing process that is designed to produce a plastic part with controlling its semisolid phase. In this research, the equipment of filament depositor is designed and tested to make the product filament deposition. With operation condition observation, the optimal temperature and pressure of deposition process was determined. These experiments used PVC as crystalline material and  polypropylene as amorphous material. To optimize this process, the tensile strength and density test were conducted. The shape of tensile test specimens is based on ASTM 638 standard and made in 3 orientations deposition path, namely: in 0 degree, 45 degree and 90 degree from load force axis. To found the most accurate dimension, controlling the time delay, temperature of build part, feeding speed and variation deposition path was conducted. The results of experiments show that the filament deposition method can only be applied for amorphous material in which it has a semisolid phase. From the tensile strength test, the binding strength among filaments is 0.5 kg/mm2, 20% of the tensile strength of filament. And the density of a sample product, which used the filament diameter of 0.8 mm, is 0.7668 g/cm3. Accuracy of product dimension can be increased by: controlling time delay in location where the motion orientation of hopper filament is changed and controlling temperature of build part surface.
Isolasi Nano Selulosa dari Ampas Tebu dengan Proses Blending pada Berbagai Variasi Konsentrasi Saputri, Lestari Hetalasi; Sukmawan, Romi; Rochardjo, Heru Santoso Budi; Rochmadi, Rochmadi
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2018: PROSIDING SNTKK 2018
Publisher : Prosiding Seminar Nasional Teknik Kimia "Kejuangan"

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This research aimed to create nano cellulose from bagasse by simple method and equipment. Nano celllulose were isolated from bagasse in three distinct stages. Initially, the fibers were treated with 5 wt.%  NaOH solution followed by bleaching using 5 wt.% hydrogen peroxide (H2O2) in alkali condition (pH 11) to remove hemicelluloses and lignin. Then, cellulosic fibers were mechanically separated by using kitchen blender to produce nano cellulose. FT-IR analysis demonstrated that the treatments could separate gradually of lignin and hemicelluloses from the fiber. FT-IR analysis also indicated a blending result with concentrate of 0.7 wt.% has the highest crystalline structure. This results were also supported by X-ray analysis. X-ray diffraction studies revealed that Nano-cellulose (0.7 wt %) obtained have higher crystallinity (83.75%). The type of cellulose that was formed is cellulose I, as expected. Finally, It could be told that blending by using kitchen blender might be one of an alternative way to produce a nano cellulose.
The Effects of the Blending Condition on the Morphology, Crystallinity, and Thermal Stability of Cellulose Microfibers Obtained from Bagasse Sukmawan, Romi; Saputri, Lestari Hetalesi; Rochmadi, Rochmadi; Rochardjo, Heru Santoso Budi
Indonesian Journal of Chemistry Vol 19, No 1 (2019)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (468.284 KB) | DOI: 10.22146/ijc.31051


In this study, cellulose microfibers were isolated from bagasse fibers in three stages. Initially, the fibers were treated with 5 wt.% NaOH solution followed by bleaching with 5 wt.% H2O2 in an alkali condition (pH 11) to remove hemicelluloses and lignin. Whole cellulosic fibers were obtained by mechanically separating the fibers using a modified kitchen blender to produce cellulose microfibers. Morphological (Scanning Electron Microscopy (SEM)) and structural analysis of the treated fiber was performed using Fourier Transformed Infrared (FTIR) spectroscopy and X-ray Diffraction (XRD). Morphological characterization identified that the diameter of the fibers varied between 20 nm to 20 µm and the FTIR analysis demonstrated that the treatments resulted in the gradual removal of lignin and hemicelluloses from the fiber. Furthermore, the XRD studies revealed that the combination of the chemical and mechanical treatment is an effective way to increase purity of cellulose (removal of amorphous lignin and hemicellulose) and break down the microfiber into shorter crystalline parts with higher crystallinity (77.25%) than raw bagasse (40.54%). Accordingly, changing the agitation time revealed that the cellulose crystallite size in the sample varied slightly with agitation time by using a blender (3.35 nm). Finally, the higher crystallinity and crystallite size improved the thermal stability of the cellulose microfiber confirming their suitability in the manufacturing biomaterial composites.
Jurnal Teknologi Technoscientia Vol 4 No 1 (2011): Vol 4 No 1 Agustus 2011
Publisher : LPPM IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (370.966 KB)


Generally manufacturing of composite materials is performed using trial and error method.The finite element method show the capability to optimize that process.The efficient formulation for simulating high speed impact usually uses explicit dynamic method. The purpose of this research is modelling impact loading on composite panel using finite element method as a part of preprototyping impact resistant composite material.The process of impact simulation on composite panel using explicit dynamic formulation can be done using commercial application software, that done with variation on impactor velocity (200, 400, 600, 800, 900, and 1000m/s), impactor geometry likes cone and blunt, Elasticity modully of lamina composite materials, the direction of fiber as symmetric cross plies and symmetric angle plies, and the thickness, 4, 6, 10 plies.The result showed that impact simulation on composite panel using this software can be performed well, the influence of impactor velocity shows increased the Von Misses Stress with average value 2.41% (in 200-400m/s), 1.59% (in 400-600m/s), 1.28% (in 600-800 m/s), 1.20% (in 800-1000m/s). Cone A type with the smallest area of contact have the best capability to penetrated compared with B type and blunt type. Symmetric angle plies have better impact resistant compared with symmetric cross plies.