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"In cases of end-milling removal rate, depth of cut, cutting velocity and feedrate were taken into account as important factors affecting machining quality, tool fracture, tool wear and so on. Generally cutting conditions were determined on the basis of field experiences and many researches about cutting force acquisition by using dynamometer and tool shape design have been actively achieved, however quantitative data of the important influential factors for cutting conditions cannot be actually suggested. In this study axial depth of cut and radial depth of cut were taken into account as design factors among cutting conditions such as spindle RPM, feedrate, axial depth of cut and radial depth of cut by using a 3-axis micro machining system. Choosing width of machining errors as a criterion for machining quality, an approximate model was established by using "Response Surface Design". A relationship between design factors and response values was realized and cutting conditions of micro end-milling processes were optimized by using an optimization program called VisualDOC"

"[Penelitian kali ini adalah berfokus pada penguatan matriks guna mendukung sifat optimum material komposit. Penguatan matriks dilakukan dengan penambahan Al-5Ti-1B dan Al-15Sr sebagai pemodifikasi matriks serta penambahan Mg sebanyak 10 wt% sebagai agen pembasahan pada komposit. Penambahan unsur modifikasi, seperti Al-5Ti-1B bertujuan sebagai agen penghalus butir dan Al-15Sr sebagai pemodifikasi dari senyawa fasa kedua yang terbentuk pada matriks paduan aluminium. Komposit pada penelitian kali ini mencapai sifat optimum pada penambahan Ti dan Sr menjadi 0.031 wt% dan 0.06 wt%. Kehadiran unsur Ti dan Sr yang ditambahkan dalam paduan matriks menghasilkan bentuk dendrit yangterfragmentasi menjadi globular yang halus dengan dispersi fasa yang diduga adalah Mg2Si dalam morfologi chinese script yang bertransformasi menjadi fibrous kecil dan halus. Selain itu juga tidak ditemukannya fasa berbentukjarum atau platelet yang tajam yang berkontribusi terhadap deteorisasi dan penggetasan, seperti Al3Fe dalam paduan ini. Struktur yang dimiliki oleh komposit ini dianggap menjadi struktur yang baik untuk menunjang karakteristik matriks. Hal ini dipercaya sebagai alasan tingginya nilaikekuatan tarik serta keuletan yang dimiliki material. Lalu, permukaan patahan pada komposit ini juga menunjukkan kombiinasi dari patah ulet dan getas.

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The research is focused on the strengthening process of the matrix to give an outstanding characteristic of composite material. Strengthening the matrix is done by modification of Al-5Ti-1B dan Al-15Sr addition with 10 wt% Mg addition as the wetting agent. Addition of Al-5Ti-1B acts as grain refinement agent which provide more nucleating siteand restrict the growth of grains and

Al-15Sr acts as modifiers of the morphology of the second phase particles. The optimization of the composite characteristics is also followed by the maintenance of the casting process which is followed by degassing process.

After the casting process is done, the examination of mechanical properties, chemical composition and examination of the microstructure will be held. The optimum composition of the composite in this research is on the addition of Ti and Sr to be 0.031 wt% dan 0.06 wt%. These elements added to matrix give the fragmented dendritic-like structure of the (Al) as the matrix with the second phases, Mg2Si dispersed in the matrix have the fine morphology also. Then, there is observed no deteoriation morphology of phases like Al3Fe which is used to be needle like or platelet like. This morphology structure is considered to the best and wanted structure to the matrix and will give optimum characteristics. It is considered that this morphology of the composite is the reason of achieving highest UTS along with increasing in

ductility. In the observation of the fractograph, it is found that the mode of fracture is categorized to be the combination of ductile and brittle fracture mode., The research is focused on the strengthening process of the matrix to give an

outstanding characteristic of composite material. Strengthening the matrix is

done by modification of Al-5Ti-1B dan Al-15Sr addition with 10 wt% Mg

addition as the wetting agent. Addition of Al-5Ti-1B acts as grain refinement

agent which provide more nucleating siteand restrict the growth of grains and

Al-15Sr acts as modifiers of the morphology of the second phase particles.

The optimization of the composite characteristics is also followed by the

maintenance of the casting process which is followed by degassing process.

After the casting process is done, the examination of mechanical properties,

chemical composition and examination of the microstructure will be held.

The optimum composition of the composite in this research is on the addition

of Ti and Sr to be 0.031 wt% dan 0.06 wt%. These elements added to matrix

give the fragmented dendritic-like structure of the (Al) as the matrix with the

second phases, Mg2Si dispersed in the matrix have the fine morphology also.

Then, there is observed no deteoriation morphology of phases like Al3Fe

which is used to be needle like or platelet like. This morphology structure is

considered to the best and wanted structure to the matrix and will give

optimum characteristics. It is considered that this morphology of the

composite is the reason of achieving highest UTS along with increasing in

ductility. In the observation of the fractograph, it is found that the mode of

fracture is categorized to be the combination of ductile and brittle fracture

mode.]"

"Di era modern ini, material komposit telah banyak digunakan dalam berbagai keperluan industri, termasuk otomotif, aviasi, hingga kebutuhan struktural. Penggunaan material komposit dinilai memiliki beberapa keuntungan dibandingkan dengan material konvensional seperti logam dan kayu, terutama karena sifatnya yang memiliki nilai strength to weight ratio yang tinggi, tahan terhadap temperatur tinggi, dan sifatnya yang bisa dimodifikasi sesuai dengan kebutuhan. Salah satu kelemahan dari material komposit adalah rendahnya ketahanan material terhadap beban impak yang relatif besar, terlebih lagi jika pembebanan impak tersebut dilakukan secara berulang untuk jumlah siklus yang cukup banyak. Saat ini belum ada standar, baik untuk prosedur maupun rancangan alat uji, yang membahas tentang pengujian impak dan fatik secara sekaligus untuk suatu spesimen material komposit. Oleh karena itu, perancangan alat uji impak dan fatik dalam kecepatan rendah dilakukan untuk memperoleh energi impak dalam jangkauan 1 hingga 10 Joule dengan jumlah siklus sebanyak 12000 siklus setiap satu jam. Dari perhitungan perancangan sistem linear, diperoleh besar kecepatan impaktor saat menumbuk material harus mencapai 1,87 m/s, yang bisa diperoleh dengan radius crank throw sebesar 110 mm.

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In this modern era, composite materials are oftenly used for a lot of industrial needs, including automotive, aviation, and structural. Composite materials are used for their advantages instead of using conventional materials, such as steel ana wood, mainly because of their mechanical properties having high strength-to-weight ratio, high temperature resistance, and modifiable for any different needs. Composite materials have one considerable weakness, they have low resistance to relatively high impact loads. Moreover, a cyclic impact load for a long duration would have worse effect to the material. There are no standards for both testing procedures and testing machine design for composite material based impact and fatigue testing in a single machine. For that reason, an impact-fatigue testing machine is designed to provide impact energy in a range of 1 to 10 Joules with 12000 cycles every hour. From design calculation of the linear system, the impactor needs to collide with the specimen in 1,87 m/s velocity, which can be produced with a 110-mm crank throw radius."

"Pada penelitian ini dilakukan proses fabrikasi komposit Mg-Al-Sr sebagai matriks dengan penambahan penguat nano-SiC melalui metode pengecoran aduk. Penambahan fraksi volume penguat nano-SiC bervariasi yaitu sebesar 0.05 ; 0.10 ; 0.15 ; 0.20 , dn 0.25. Jika dibandingkan dengan paduan Mg-Al-Sr, penambahan partikel nano ke dalam matriks logam mampu meningkatkan sifat mekanik komposit yang dihasilkan. Penambahan fraksi volume nano-SiC sebesar 0.15 menghasilkan nilai kekerasan, harga impak, dan ketahanan aus paling optimum, serta disitribusi senyawa intermetalik yang terdispersi homogen di dalam struktur mikro. Hal ini disebabkan oleh semakin banyak penguat nano-SiC yang ditambahkan, maka aglomerasi cenderung meningkat sehingga proses penguatan menjadi kurang efektif. Karakterisasi komposit yang dilakukan adalah pengujian komposisi menggunakan OES, EDX, dan XRD; pengamatan struktur mikro menggunakan OM dan SEM; serta pengujian berupa pengujian kekerasan, impak, dan aus.

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Magnesium composite with Mg Al Sr as the matrix reinforced by nano SiC particles have successfully fabricated by stir casting process. Addition of nano SiC into magnesium matrix varies by 0.05 0.10 0.15 0.20 and 0.25 in volume fraction. Compared with Mg Al Sr alloy, addition of nano particles into matrix improves mechanical properties of composites. It is observed that the optimum composition of nano SiC is 0.15 Vf which have the highest hardness value, impact toughness, and resistance to abrasion. It is also abserved that addition 0.15 Vf nano SiC modify the microstructure of composite by dispersing the intermetallic compound. The addition of Vf nano SiC could have tendency to agglomerate and strengthening mechanism is not effectively occurred. The result of chemical characterization using OES, EDX, XRD, metalloghraphy using OM and SEM, mechanical testing using hardness, impact, and abrasive testing."

"ABSTRAKPenulisan ini membahas mengenai perancangan desain motor BLDC 12 slot dan 8 pole dengan kapasitas 40 kW menggunakan material komposit, dalam hal ini Somaloy, pada inti motor. Penelitian berfungsi untuk melihat pengaruh perubahan diameter stator, panjang stack, diameter rotor, ketebalan magnet, jumlah lilitan dan material yang digunakan untuk melihat perbandingan performa berdasarkan keluaran torsi, daya keluaran, dan faktor daya pada motor. Hasil penelitian didapatkan bahwa keluaran nilai torsi pada material Somaloy sebesar 97.9 Nm, daya keluaran mencapai 41 Nm, dan faktor daya sebesar 0.72. Simulasi tersebut menunjukan penggunaan bahan komposit pada inti motor mampu menghasilkan keluaran berupa torsi, daya keluaran, dan faktor daya yang cukup baik. Simulasi motor menggunakan software Finite Element Method FEM.

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ABSTRACTThis research discusses about the design of BLDC motor 12 slots and 8 poles with a capacity of 40 kW using composite material, in this case is Somaloy, at its core. The research functioned to see the effect of stator diameter change, stack length, rotor diameter, magnet thickness, number of turns, and material used to see performance comparison based on torque output, output power, and power factor. The results obtained that the output value of torque on Somaloy material is 97.9 Nm, output power is 41 Nm, and power factor is 0.72. The simulation results show that the use of composite materials on the motor core is capable of producing good output such as torque output, output power, and power factor. Simulation software motor using Finite Element Method FEM."