This study aims to analyzed the effect of male-female chamfer configuration in a rotary friction welding of alumunium 6061. The male-female chamfer configuration tend to make an inner chamfer and outer chamfer shape between two connected materials. The chamfer angle analyzed varies in 300, 450, and 600 where the friction time also varies in 1 and 2 minute. The results shows that the tensile strength increased along with smaller chamfer angle and longer friction time. The largest tensile strength of 33.92 kgf / mm2 was obtained in the variation B30. The smallest tensile strength of 12.20 kgf/mm2 gained in specimen A60. Smaller chamfer angle leads to a larger friction areas which caused the welding contact areas also wider. The male-female chamfer method slopely increase the contact area by 78%, 33% and 12% than normal circle profile.

The vehicle is one of basic needs for supporting mobility of people. Comfort and safety are demanded in every vehicle, especially in its suspension system. The existing suspension systems can’t maximize comfort and safety because it is still hydraulic and pneumatic based, without magnetic system. The purposes of the analysis is building magnetic suspension system with variations at the amount of coil and analyzing absorbing time. The methods of the analysis are determining concept, making the designs, determining components specification, making device block diagram, making wiring diagrams, making the device, taking the absorbing time datas, and the analyzing the data. The results of the analysis are the amount of coil is straight compared to the magnetic force and absorbing time. The most significant solenoid is the one which has 900 coils and has absorbing time at 9.6 seconds.

Telah banyak diteliti metode stophole untuk menghambat pertumbuhan retak pada bahan logam, namun belum ada penelitian tentang metode stophole ini untuk menghambat retak pada bahan komposit. Penelitian ini mengguankan komposit epoxy dan serat kaca dengan katalis epoxy hardener (polyaminoamide), arah serat yang digunakan adalah serat acak, lapisan komposit terdiri dari 4 lapis,  dengan komposisi 30% serat, 69.7% resin, dan 0,3% katalis digunakan. Spesimen uji menggunakan CTS sesuai standar pengujian ASTM E 647 dengan retak awal sepanjang 20 mm dengan variasi diameter lubang stophole 2mm, 3mm, 4mm, dan 5mm serta jarak lubang dan retak 5mm, 10mm, dan 15mm. Hasilnya didapatkan jarak lubang yang paling optimum yang menyebabkan tegangan tarik tertinggi terletak pada jarak 10mm dari ujung retak, dan diameter optimumnya adalah 5mm dengan kekuatan tarik maksimum 22.74 Mpa, lebih tinggi daripada kekuatan tarik maksimum tanpa stophole (13.3 Mpa). Sehingga dapat disimpulkan adanya variasi stophole mempengaruhi tegangan tarik maksimum komposit epoxi serat gelas, karena pada ujung retak dan sisi lubang terdapat pemusatan tegangan, dan juga perbedaan mode patahan.

Metal cutting process (cutting process) is to cut metal to get the shape and size and quality of the planned cutting surface. The metal cutting process is carried out with special tools, according to the type of cutting process. So the tools for one process cannot be used in another process, even for similar processes, the tools cannot be exchanged if the cutting plans are not the same. Lathe process is a machining process to produce cylindrical machine parts which are carried out using a Lathe. Its basic form can be defined as the machining process of the outer surface of cylindrical or flat lathe objects. Polyvinyl Chloride, commonly abbreviated as PVC, is the third-order thermoplastic polymer in terms of total usage in the world, after Polyethylene (PE) and Polypropylene (PP). Worldwide, more than 50% of PVC produced is used in construction. PVC is produced by polymerizing vinyl chloride monomers (CH2 = CHCl). Because 57% of its mass is chlorine, PVC is the polymer that uses the lowest petroleum feedstock among other polymers. This research follows up the selection of configuration of the lathe machining process using plastic work pieces. In this study, Maximat V13 lathe and PVC type plastic were used. The variation of machining processes are spindle rotation (320, 540, and 900 rpm), feeding speed (0.07, 0.14, and 0.28), the use of tool types (carbide and HSS) and cooling (without cooling, coolant, and oil). So, with this research, it is expected that the optimal parameters in determining the configuration of the lathe machining process on a PVC work piece to produce a good turning surface can be achieved