Manufaktur dan Uji Kinerja Proses Vacuum Forming Untuk Bahan Polymethyl Methacrylate (PMMA)

AbstrakMesin pembuat kemasan yang sederhana dan murah dengan kinerja yang memadai diperlukan untuk meningkatkan nilai ekonomis produk industri rumah tangga (UKM). Penelitian ini bertujuan untuk membuat dan menguji kinerja mesin vakum forming pada bahan Polymethylmetacrylate (PMMA).Tahapan dalam pembuatan mesin ini adalah studi rancangan, manufaktur bagian mesin, cetakan, perakitan dan uji coba kinerja. Cetakan dibuat dari bahan kayu jati berukuran 140 mm x 210 mm x 15 mm. Pengujian kinerja mesin dilakukan dengan memanaskan lembaran plastik PMMA tebal 0.25 mm pada variasi waktu pemanasan 15, 20 dan 25 detik dan waktu vakum 5, 10 dan 15 detik, menggunakan pemanas 100 watt dan tekanan vakum maksimum 12 kPa. Dimensi dan geometri produk dibandingkan dengan cetakan dan dievaluasi dengan pengukuran linier serta pengamatan visual.Hasil pengujian menunjukkan bahwa kombinasi waktu pemanasan 15 detik dan waktu vakum 5 detik menghasilkan produk dengan radius yang besar pada bagian dasar. Kombinasi waktu pemanasan 20 detik dan waktu vakum 10 detik dapat memperkecil ukuran radius. Hasil cetakan yang mendekati bentuk cetakan diperoleh dengan parameter suhu pemanasan 105 ℃, waktu pemanasan 25 detik dan waktu vakum 15 detik.AbstractA simple and inexpensive packaging machine with adequate performance is needed to increase economic added value of the smal scale industries. This study aims to manufacture and to evaluate the performance of customized vacuum forming machine on Polymethylmetacrylate (PMMA)l. Manufacturing of components and molds, assembly and performance testing have been carried out to build the machine. The mold was made of teak wood with the dimension of 140 mm x 210 mm x 15 mm. Machine performance testing was done by heating a 0.25 mm thick PMMA sheet with heating time variation of 15, 20 and 25 second and vacuum time of 5, 10 and 15 second, respectively. The heating power was 100 watts and the maximum vacuum pressure was 12 kPa. Product quality were compared with mold by linear measurements and visual observations.The processing parameter of 15 second heating time and 5 second vacuum time produced a specimen with a large radius at the bottom. The combination of 20 second heating time and 10 second vacuum time reduced the size of the radius. The best product can be obtained with a heating temperature of 105 ℃, heating time of 25 second and a vacuum time of 15 second.

Physical Characteristics of ZnO nanorods synthesized by low power DC thermal plasma

Study on synthesis and characterization of ZnO nanorods are reported. Low power DC thermal plasma was successfully employed to fabricate these ZnO nanorods. Several testing were conducted including X-ray fluorescence (XRF), particle size analyzer (PSA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The diameter of resulted ZnO nanorods varies from 43 nm to 200 nm which can be seen from SEM images and its length varies from 160 nm to 1000 nm. These nanopowders are in rod shape as can be seen clearly from TEM images. The XRD data shows a sharp peak at 36.21o which indicates a good crystal growth and agrees well with the standard data (JCPDS card no. 36-1451). Effects of electrical current variations of 20, 25 and 30 Ampereere to the size of ZnO nanorods are also indicated from aspect ratio of about 8.27, 8.44 and 8.81 respectively. The ultraviolet (UV) absorption test results show that the ZnO nanorods can absorb UV with the absorbance ranges are about 300 nm and 340 nm wave lengths as well as the peak is at the wave length of 311 nm. Photoluminescence test confirm that the ZnO spectra are in blue emission with the optimum excitation wavelength of 240 nm. It can be concluded that this method is well proven in synthesizing ZnO nanorods having perfect single crystalline size, high purity compound, UV-block ability and good luminescence characteristics by spending low electrical power

Perancangan Polybag Knockdown Dengan Material Polyethylene Terephthalate (PET)

During the Covid-19 pandemic, the need for food was one of the problems faced by the government. The government urges the public to do independent food planting using polybag planting media as one solution to overcome this problem. However, single-use polybags can increase the amount of plastic waste, which is still unresolved. This study aims to design the value of the knockdown polybag product and gain strength from the knockdown product design. Knockdown Polybag product design using the VDI 2222 method (Verein Deutscher Ingenieure / German Engineers Association). This method helps facilitate designing products and learning for beginners and can optimize the productivity of designers to find the most optimal and efficient problems. After determining the method used, the next step is planning, conceptualizing, designing, and completing knockdown polybag products. The result of the design concept from the VDI 2222 method is an alternative overall function (AFK) 2 which has a square cross-section, is cones-shaped to facilitate plant transfer applications on agricultural land, and uses a hook locking model, which is flexible, and easy to assemble and disassemble. The product design of knockdown polybags has been obtained to meet the needs according to those on the market. Therefore, knockdown polybags can be produced and used to make planting more accessible and reduce costs for farmers

Analisis Pengujian Tarik dan Sebaran unsur pada Pengelasan Aluminium – Mild Steel menggunakan Metode Cold Metal

The technology that has been developed in recent years is the production of fusion welded plates between two different materials, for example, steel with other materials such as aluminum. Combining the two materials, aluminum and mild steel, will undoubtedly produce a material connection with good properties, for example, in a vehicle car frame. However, these two materials have different melting points, mild steel has a high melting point, and aluminum has a low melting point in the inner layer. This research aims to determine the welding results and the microstructure between aluminum plates and mild steel. The Cold Metal Transfer (CMT) welding process provides a potential method for joining dissimilar metals. In this study, various 4 mm thick aluminum alloys (Al 1100) were joined to 4 mm thick mild steel (SPHC) by CMT welding technology. It was concluded that combining aluminum alloys with mild steel using the cold metal transfer method was feasible. The optimum process variable for welding aluminum-mild steel dimensions 250 mm × 100 mm × 4 mm can be obtained with ER70S-6 wire, ArCO2 shielding gas, wire feed speed 13 m/min, and welding speed e8 mm/s.The tensile strength of the joint first increases and then decreases as the welding current increases, the highest tensile strength can reach 73.35 MPa

SINTESIS MATERIAL SEMIKONDUKTOR ZnO DIDOPING Cu UNTUK MODUL TERMOELEKTRIK BERBASIS MATERIAL ZnO

Pembuatan material semikonduktor zinc oxide (ZnO) didoping copper (Cu) bertujuan mendapatkan material semikonduktor tipe-p ZnO1-xCuxO yang baik untuk modul termoelektrik telah berhasil dibuat. Material zinc nitrate tetrahydrate dan copper nitrate trihydrate merupakan material awal yang kemudian digabungkan melalui proses percampuran serbuk dalam larutan dengan kadar Cu yang bervariasi 0%, 2%, 4%, 6% dan 8% mol. Selanjutnya, larutan tersebut dikeringkan, dikalsinasi dan dikompaksi menjadi bentuk pellet. Pellet tersebut disintering dengan temperatur 1300oC. Hasil pengujian karakteristik ZnxCu1-xO menunjukkan material dengan kandungan Cu 2% mol dan pengujian pada temperatur operasional 450oC menghasilkan nilai figure of merit yang terbesar yaitu 0,55 karena memiliki nilai hole carrier concentration yang paling optimal dengan nilai konduktivitas listrik 3514 S/m, konduktivitas termal 1,56 W/mK, dan koefisien seebeck 615,3 μV/K. Besarnya kandungan material doping mempengaruhi besarnya nilai karakteristik dari material semikonduktor ZnxCu1-xO untuk modul termoelektrik. Kata Kunci: Material Semikonduktor Tipe-p, Termoelektrik Material Oksida, ZnO doping C

STUDI EKSPERIMENTAL PENGGERAK MULA TERMOAKUSTIK PISTON AIR DENGAN DIAMETER SELANG OSILASI 1 INCI

Penggerak mula termoakustik adalah salah satu renewable energy yang mengubah energy panas menjadi energi gas dan suara sehingga dapat menggerakkan air. Fenomena ini sangat menarik untuk diteliti. Penelitian ini akan menyajikan sebuah model penggerak mula termoakustik sehingga menghasilkan daya dan efisiensi energi yang cukup tinggi. Model ini terdiri dari  bagian pendingin, regenerator dari steelwool dengan panjang 60mm, tabung resonator dan bagian osilasi berupa selang transparan dengan diameter 1 inci. Energi mekaniknya berupa gerak osilasi fluida zat cair dalam hal ini air yang berada di dalam selang yang sudah dibuat sedemikian rupa sehingga membentuk profil U. Penelitian ini dilakukan menggunakan tabung resonator yang ukuran tabung outside 15,7 x 70 mm, outside 20 x 90 mm, dan outside 25,2 x 100 mm. Model dengan ukuran tabung resonator outside 25,2 x 100 mm menghasilkan daya terbesar sebesar 0,226 watt dan efisiensi energi terbesar sebesar 0,279 %. Semakin besar dimensi tabung resonator, daya dan efisiensi yang dihasilkan akan semakin besar. Kata kunci: renewable energy, penggerak mula termoakustik, tabung resonato

Pengaruh Sudut Kemiringan Tool Friction Stir Welding terhadap Sifat Mekanik dan Struktur Mikro pada Sambungan Plat AA5083

 AbstrakPenelitian ini bertujuan untuk mempelajari pengaruh sudut kemiringan tool pada proses friction stir welding (FSW) terhadap sifat mekanik dan struktur mikro sambungan las pelat aluminium sheet 5083. Pengelasan menggunakan mesin milling dan material welding tool dari jenis Bohler K100 dengan kekerasan 59HRc. Proses pengelasan ini memiliki kecepatan putar spindle 1125 rpm, kecepatan pengelasan 30 mm/menit, dan kedalaman pembenaman tool 3,9 mm. Variasi sudut kemiringan tool terdiri dari 1°, 2°, 3° dan 4°.  Pengujian spesimen  dengan uji tarik, uji tekuk, uji kekerasan dan pengamatan secara makro dan mikro. Hasil penelitian menunjukan kekuatan tarik tertinggi (312,5MPa ) pada sudut kemiringan 3°. Kekuatan tekuk uji face bending tertinggi (655,1MPa ) dan root bending tertinggi (651,8MPa ) pada sudut kemiringan 2°. Daerah retreating side rata-rata mempunyai kekerasan yang lebih tinggi dibanding advancing side. Sudut kemiringan tool sampai 3° meningkatkan kekuatan tarik dan di atas sudut tersebut membuat kekuatan tarik menurun, sedangkan nilai  kekuatan tekuk optimal terjadi pada sudut 2°. Pada foto mikro, semakin besar sudut kemiringan tool membuat ukuran butir pada daerah HAZ semakin besar tetapi tidak terlalu berpengaruh terhadap nugget.AbstractThis research aims to study he effect of tool tilt angle of friction stir welding (FSW) process on the microstructure and mechanical properties of 5083 aluminum plate weld joints. The welding used a milling machine and welding tool material is from the Bohler K100 type possessing 59HRc hardness. This welding used spindle rotational speed of 1125 rpm, welding speed of 30 mm/minute, and tool immersion depth of 3.9 mm. The variations  of tool tilt angle are 1°, 2°, 3° and 4°. The specimens were tested tension, bending, hardness, as well as macron and microstructure observations. The results showed the highest tensile strength (312.5MPa) was obtained at a slope of 3°. The highest bending strength of the face bending test (655,1MPa) and the highest root bending (651,8MPa)are at a slope angle of 2°. The average retreating side area has higher hardness than the advancing side does. The increase of tilt angle up to 3° increases the tensile strength and futher increase makes tensile strength decrease, while the optimum buckling strength obtained at an angle of 2°. Photo micrograph shows that the larger the angle of the tool makes the grain size in the HAZ area coarser but not too influential on the nugget