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Abstrak :
Penelitian ini bertujuan untuk mengetahui perbedaan nilai kekasaran permukaan lempeng resin akrilik polimerisasi panas dengan serat dan tanpa serat. Penelitian menggunakan 32 spesimen dengan 16 spesimen untuk masing-masing kelompok. Nilai kekasaran permukaan (Ra) diukur dengan menggunakan Surface Roughness Tester pada 5 tempat berbeda dengan masing-masing panjang evaluasi 7,5 mm. Hasil penelitian ini menunjukkan bahwa tidak terdapat perbedaan bermakna antara nilai rata-rata kekasaran permukaan resin akrilik polimerisasi panas dengan serat dan tanpa serat. ......The aim of this study was to determine the difference of surface roughness value of veined and non-veined heat-cured acrylic resin. Thirty two specimens of acrylic resin were used in this study with 16 specimens of each group. Surface roughness value (Ra) was measured using Surface Roughness Tester at 5 different places with each 7,5 mm of evaluation length. The result of this study showed that there was no significant difference between the mean of surface roughness value of veined and non-veined heat-cured acrylic resin.

Abstrak :
Engineering merupakan ilmu yang mempelajari proses merekayasa pembuatan suatu produk sehingga mempunyai fungsi yang bermanfaat sesuai dengan desain yang dirancang. Dalam pembuatan suatu produk pasti menemukan kendala ? kendala tertentu sehingga harus dilakukan analisa kembali dalam menemukan jalan keluar untuk menyelesaikan kendala ? kendala yang ditemui. Salah satu kendala yang sering ditemui dalam proses pembuatan suatu produk adalah adanya efek secara fisik kepada benda kerja yang dilakukan proses permesinan seperti panas maupun tegangan yang dapat mengakibatkan kerusakan pada benda kerja. Peneliti ? peneliti sebelumnya telah melakukan riset jangka panjang dan menemukan salah satu cara yang dapat dijadikan solusi dalam proses permesinan. Alternatif yang ditemukan adalah penggunaan bakteri yang digunakan sebagai cutting tool dalam proses permesinan. Beberapa keunggulan yang dimiliki oleh proses biomachining adalah ramah lingkungan, tidak terjadi thermal damage pada permukaan benda kerja serta hemat energi. Dalam peneltian sebelumnya telah dilakukan proses kareakterisasi terhadap material nickel dimana terdapat pertambahan kedalaman permesinan seiring dengan bertambahnya waktu proses biomachining, sehingga pada penelitian kali ini peneliti akan melakukan variasi waktu yang lebih lama dan optimalisasi kondisi temperatur lingkungan proses biomachining pada suhu 330C, selain itu bentuk pola yang akan digunakan pada proses biomachining berbentuk lingkaran dengan tujuan untuk melakukan rekayasa dari bentuk microneedle, microneedle merupakakan jarum dalam bentuk micro yang biasa digunakan sebagai alat uji kesehatan dan proses pemberian vaksinasi pada manusia . Proses rekayasa microneedle bermula dari pembuatan pola lingkaran dengan ukuran 3mm hingga kecil 400μm dimana akan dilakukan perbandingan kontur dan sufrace roughness dari setiap hasil lingkaran yang terbentuk pada proses biomachining. ...... Engineering is a knowledge that studies about makings a product which has usefull function according to design . In makings a product must find some problem that has to be reviewed back by re-analysis to find a way out or find the solution. One of constraint which often been found when creating product is physicall effect when processing engineering machinery that create hot condition and also tension who can damage the object. Previous researcher have research in long time and they found several ways which can be the solution in engineering process. One of the famous alternative is biomachining which used bacteria that is utilized as cutting tool in machinery process. Some reason which had by biomachining process are environmentally-friendly, there were not happening thermal damage on object surface and energy saving. In previous the researcher did characterisation process to significant nickel characteristic where the result was the depth of material is increased proporsional to increased condition of biomachining time , so this time the researcher will increased time variation and optimalize the condition of temperature in biomachining process which is 33 0 C, on the other side researcher will make a new pattern form that will be used on biomachining process, that new form is a circle that will be used as a microneedle mask, microneedle is several needle which shaped in micro that is different to the ordinary one, microneedle was being utilized as tool for vaccination application on human .Microneedle enineering started from making several pattern with size 3mm until 400μm, until then researcher will do contour and surface roughness comparison of each model which is the result from biomachining process.

Abstrak :
ABSTRAK
Penelitian ini bertujuan untuk menganalisis pengaruh perendaman resin komposit nanohybrid dalam obat kumur mengandung etanol dengan waktu berbeda terhadap kekasaran permukaan. Dua puluh empat spesimen resin komposit nanohybrid dibagi menjadi 4 kelompok perendaman: obat kumur etanol 17 dan 26,9 selama 1,5 jam dan 3 jam. Kekasaran permukaan diukur menggunakan surface roughness tester Mitutoyo SJ301. Berdasarkan analisis statistik uji one-way ANOVA dan uji Tukey.

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ABSTRACT
The aim of this study was to analyze the effect of ethanol containing mouthwash with different concentration and duration of immersion on the surface roughness of nanohybrid composite resin. Twenty four specimens of nanoybrid composite resin were divided into 4 groups of immersion 17 ethanol containing mouthwash, and 26,9 ethanol containing mouthwash for 1,5 hours and 3 hours. Surface roughness was measured using SJ301 Mitutoyo surface roughness tester. Statistical analysis of one way ANOVA and Tukey test.

Abstrak :

Di pekerjaan ini, pembelajaran mengenai efek kekasaran permukaan (Ra) terhadap umur kelelahan perpaduan Aluminum 7075-T6 dilakukan. Berdasarkan pekerjaan sebelumnya,  umur kelelahan adalah fungsi dari kekasaran permukaan material/spesimen. Semakin kasar permukaan spesimen, semakin menurun umur kelelahannya. Sebaliknya, semakin halus permukaan specimen maka umur kelelahannya meningkat. Dalam kasus ini, kekasaran (Ra) hanya didapat dari proses machining. Selanjutnya, dibuatlah suatu faktor koreksi yang merupakan perbandingan dari umur kelelahan specimen dengan nilai Ra tertentu terhadap umur kelelahan specimen ideal. Kemudian, digambarkan sebuah kurva nilai faktor koreksi sebagai fungsi dari Ra. Simulasi keausan dengan menggunakan perangkat lunak komersil telah dilakukan untuk memprediksi umur kelelahan pada kondisi ideal. Kemudian, umur kelelahan untuk spesimen dengen berbagai kondisi kekasaran dapat diestimasi dengan factor koreksi yang didapat dari atas. Dapat disimpulkan bahwa kurva yang menunjukan hubungan Ra dengan faktor koreksi dapat digunakan untuk memprediksi umur kelelahan secara efisien saat simulasi.

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In this work, the effect of surface roughness to the fatigue life of 7075-T6 Aluminum Alloy were studied. The objective is to estimate values of surface factor correction of 7075-T6 Aluminum Alloy and its fatigue life using the obtained correction factors. Based on previous research, a function of fatigue life in terms of surface roughness were obtained. As the surface roughness increases, fatigue life decreases and vice versa. In this case, the Ra value were obtained from machining process only. First, an estimated surface factor correction was obtained as the fatigue limit ratio of specimen with certain Ra value to specimen having ideal surface condition. Then, a function of surface factor correction in terms of Ra were generated. After that, a fatigue simulation was conducted using commercial software to predict fatigue life at the ideal surface condition. Finally, fatigue life for various value of Ra can be estimated using the correction factors obtained. It was concluded that the function of surface factor correction in terms of Ra was applicable to estimate the fatigue life efficiently during simulation.

Abstrak :
Material Ti6Al4V sangat umum digunakan sebagai Biomaterial karena memiliki karakteristik yang mendukung sebagai Biomaterial. Namun, sejumlah kecil kadar aluminium (Al), vanadium (V), dan Titanium (Ti) dapat terlepas sehingga dapat berdampak bagi tubuh manusia. Penelitian ini bertujuan untuk mengevaluasi stabilitas lapisan oksida pada permukaan implan Ti-6Al-4V yang diberikan pembebanan mekanis berupa bending sesuai dengan kontur wajah manusia. Preparasi Ti-6Al-4V dilakukan hingga permukaan tampak seperti mirror-like dan bersih dari unsur pengotor. Proses pembebanan mekanis menggunakan metode 3-point bending dengan variasi strain 0,01586, 0,016022, 0,015916. Sampel kemudian akan diimersi dalam larutan HBSS selama 21 hari dan 28 hari. Pengaruh strain terhadap kekasaran permukaan pasca imersi diidentifikasi melalui pengujian Surfcom, pengamatan morfologi dan karakterisasi unsur pada permukaan lapisan TiO2 sebelum dan sesudah proses imersi dengan larutan HBSS dengan SEM-EDS dan OM. Hasil penelitian memerlihatkan bahwa semakin tinggi pembebanan yang diberikan akan semakin berpengaruh terhadap ketidakstabilan lapisan pasif titanium oksida. Selain itu, ditemukan microcrack pada lapisan oksida pada tiap variasi strain yang diberikan. Hasil pengujian imersi menunjukkan bahwa microcrack yang terdapat pada lapisan oksida menjadi tempat utama terdepositnya komponen HBSS. Selain itu, terjadi peristiwa stress corrosion cracking pada lapisan oksida di permukaan yang dibuktikan dengan perubahan warna oksida pada permukaan Ti-6Al-4V. ......Ti6Al4V material is commonly used as a biomaterial due to its supportive characteristics for biomedical applications. However, a small amount of aluminum (Al), vanadium (V), and titanium (Ti) can be released, which can have implications for the human body. This study aims to evaluate the stability of the oxide layer on the surface of Ti-6Al-4V implants subjected to mechanical loading in the form of bending according to the contour of the human face. The Ti-6Al-4V specimens were prepared until the surface appeared mirror-like and free from impurities. Mechanical loading was applied using the 3-point bending method with strain variations of 0.01586, 0.016022, and 0.015916. Subsequently, the samples were immersed in HBSS solution for 21 and 28 days. The effect of strain on the surface roughness after immersion was identified through Surfcom testing, morphology observations, and elemental characterization of the TiO2 layer using SEM-EDS and OM. The results showed that higher applied loading had a greater impact on the instability of the titanium oxide passive layer. Additionally, microcracks were found in the oxide layer for each strain variation applied. The immersion test revealed that microcracks served as primary sites for the deposition of HBSS components. Furthermore, stress corrosion cracking occurred in the oxide layer on the Ti-6Al-4V surface, which was evidenced by changes in the oxide coloration on the surface.

Abstrak :
Surface roughness plays an important role in product quality. In this study effects of cutting speed workpiece hardness, feed rate and depth of cut on surface roughness in the finish hard turning of DF-3 hardened steel were experimentally investigated Cubic boron nitrite inserts and ceramics with through - hardened DF-3 steel bars were used Four factor-two level fractional experiments were conducted and statistical analysis of variance was performed During hard turning experiments, roughness of the machined surface was measured. This study shows that the effects of workpiece hardness, depth of cut, feed rate and cutting speed on surface roughness are statistically significant. The ejects of two factor interactions of the cutting speed and the workpiece hardness, the cutting speed and the feed rate, and the cutting speed and depth of cut are also appeared to be important. Especially, CBN suitable for high or tow cutting speed because on the 55.4 to 59.6 HRC hardness range resulted in better surface roughness.

Abstrak :
This research was done to investigate influence of the base metal surface roughness on the BAg-8 spreading behavior and to get a proper surface roughness number for large area brazing. The filler metal was melted at 830o C for 15 minutes on a S50C surface for with various roughness levels. After solidified, the spreading area was observed and characterized in macro and micro scale. The results show that physically the filler spreading consists of two kinds of spreading forms: true and apparent filler spreading with composition of the both being almost same; 77% Ag and 23% Cu. For some roughness numbers, irregularities in uniformity of the heating and cooling process on the filler and dissolving of contaminant into the molten filler caused the true spreading that tend to separate became several parts and tend to flow out from initial placement. Increasing of the surface roughness tends to increase the capillarity effect and to decrease imbalance in the surface tension. Optimum surface roughness was obtained at Rz = 0.92. At this number, the ratio, as well as fitness of the true spreading with initial condition, was at the maximum. During the application process, this condition is predicted as being able to prevent or avoid weaknesses in the joint, thereby increasing the joint strength and its appearance quality.

Abstrak :
Peningkatan kekasaran permukaan dilakukan dengan membentuk lapisan porous oksida melalui anodisasi pada material Screw Dental Implant (Zr-Ti)-5Al. Material As-cast dibuat menggunakan Single Arc Melting Furnace 3000°C. Variasi unsur Ti dilakukan untuk mendapatkan sifat mekanik dan ketahanan korosi yang baik. Ti berperan sebagai ? stabilizer, semakin banyak Ti pada paduan ukuran butir yang lebih besar. XRD menunjukkan bahwa Al berperan sebagai solid solution strengthening dan membentuk fasa Zr3Al, EDS menunjukan peningkatan %berat unsur Al sebagai senyawa intermetalik. Micro Hardness Vickers menunjukkan bahwa nilai tertinggi tercapai pada SP-1 dengan nilai 637,94HV. Mofrologi permukaan memiliki kekasaran sebesar 200nm. Kekasaran permukaan yang rendah menghasilkan laju korosi yang rendah, laju korosi terendah dihasilkan SP-3 sebesar 14,336x10-5mpy (outstanding). Anodisasi dilakukan pada temperatur 25°C, 1 jam, larutan NaF 0,5M, 15V dan 1,25mA. Terbentuk lapisan dengan ketebalan rata-rata 124,075µm. Pemeriksaan AFM menunjukkan peningkatan kekasaran menjadi 0,8µm lapisan terdiri dari senyawa ZrO2, TiO, dan Al2O3. SP-1 yang telah mengalami anodisasi menunjukkan laju korosi yang semakin rendah 10,821x10-9mpy. ......The increase in surface roughness was carried out by forming a porous oxide layer through anodization on the Screw Dental Implant (Zr-Ti)-5Al material. As-cast material is made using a Single Arc Melting Furnace 3000°C. Variation of the Ti element was carried out to obtain good mechanical properties and corrosion resistance. Ti acts as a ? stabilizer, the more Ti in the larger grain size alloys. XRD shows that Al acts as a solid solution strengthening and forms the Zr3Al phase, EDS shows an increase in the weight % of elemental Al as an intermetallic compound. Micro Hardness Vickers shows that the highest value is achieved in SP-1 with a value of 637.94HV. The surface morphology has a roughness of 200nm. Low surface roughness results in a low corrosion rate, the lowest corrosion rate is produced by SP-3 of 14,336x10-5mpy (outstanding). Anodization was carried out at 25°C, 1 hour, 0.5M NaF solution, 15V and 1.25mA. A layer is formed with an average thickness of 124.075µm. AFM examination showed an increase in roughness to 0.8µm the layer consisting of ZrO2, TiO, and Al2O3 compounds. SP-1 which has undergone anodization shows a lower corrosion rate of 10,821x10-9mpy.

Abstrak :
Biomachining merupakan salah satu proses alternatif dalam fabrikasi mikro. Beberapa keunggulan yang dimiliki dalam proses biomachining adalah ramah lingkungan, tidak terjadi thermal damage pada permukaan benda kerja, dan efisien energi. Dalam penelitian biomachining multi-axis sebelumnya inklinator sudah dikembangkan dengan menggunakan konsep sendi peluru pada fixture sehingga memiliki dua sumbu rotasi dan sudut inklinasi dapat dilakukan ke segala arah. Telah dilakukan percobaan biomachining pada permukaan benda kerja tembaga dimana tiap - tiap posisi diberi sudut inklinasi 20° dan 40°. Percobaan dilakukan dalam waktu 6 jam untuk tiap - tiap posisi inklinasi. Pada penelitian kali ini proses yang sama dilakukan pada benda kerja nikel. Percobaan dilakukan dengan temperatur ruangan 23 - 25°C. Tujuan dilakukan penelitian ini adalah untuk melihat karakterisasi dan bentuk profil permukaan dari benda kerja nikel dengan perlakuan inklinasi sudut yang berbeda. Selain itu penelitian ini juga bertujuan untuk melihat perbandingan surface roughness dan bentuk profil permukaan dari benda kerja nikel dan tembaga yang telah melalui proses biomachining dengan sudut inklinasi yang sama. Berdasarkan hasil pengukuran didapatkan nilai material removal rate (MRR) dari benda kerja nikel dengan perlakuan inklinasi 20° dan 40° sebesar 0,102 mm3/jam dan 0,129 mm3/jam. Tingkat kekasaran yang paling rendah adalah nikel 40o dengan nilai rata-rata Ra 1,76 ± 0.31 µm dan diikuti oleh nikel 20o dengan nilai rata-rata Ra 2,41± 0.39 µm. Nilai rata-rata tingkat kekasaran benda kerja tembaga yang didapat dari penelitian sebelumnya lebih besar dibandingkan dengan benda kerja nikel. Dari hasil perbandingan dengan penelitian sebelumnya menunjukkan bahwa benda kerja tembaga memiliki kedalaman permukaan lebih besar dibanding dengan benda kerja nikel. ...... Biomachining is one of the alternatives in the micro fabrication process. The advantages of biomachining is environmentally friendly, no effect of thermal damage on the workpiece surface, and energy efficient. Previously, the study of multi-axis biomachining inklinator have been developed using the concept of joint bullets on his desk so that it has two axes of rotation and the angle of inclination which can be done in any direction. Biomachining experiments have been conducted on the surface of the copper workpiece where each position given the angles of inclination of 20° and 40°. Experiments performed within 6 hours for each position of inclination. In the present study, the same process carried out on nickel workpiece. The experiments were performed with room temperature 23-25°C. The purpose of this study is to look at characterization and profile shape of nickel with different inclination angles . In addition , this study aimed to compare the surface roughness and the shape of the workpiece surface profile nickel and copper that has been through the process biomachining with the same angle of inclination . Based on the results, the value of material removal rate ( MRR ) from nickel workpiece with inclination angle 20° and 40° are 0.102 mm3/hour and 0.129 mm3/hour . The lowest level of roughness (Ra) is nickel 40o with an average value 1.76 ± 0.31 µm and followed by nickel 20o with an average value 2.41 ± 0.39 µm. Average roughness of the copper samples were obtained from previous studies is greater than the nickel workpiece. From the comparison with previous research showing that copper workpiece surface has a depth greater than the nickel workpiece.

Abstrak :
Latar Belakang: Perawatan restorasi resin komposit nanofilled dan nanohybrid memerlukan prosedur pemolesan untuk mengurangi tingkat kekasaran permukaan sehingga permukaan halus dan mengkilap. Tujuan: Membandingkan kekasaran permukaan resin komposit nanofilled dan nanohybrid setelah pemolesan menggunakan teknik multiple-step. Metode: 40 spesimen resin komposit yang dibagi ke dalam 2 kelompok 20 spesimen nanofilled Filtek Z350XT A dan 20 spesimen nanohybrid Filtek Z250XT B dipersiapkan kemudian dipoles. Setelah direndam dalam saliva buatan selama 24 jam, tingkat kekasaran permukaan diukur dengan surface roughness tester. Hasil: Hasil rerata tingkat kekasaran permukaan beserta standar deviasi kelompok A adalah 0,0967 m 0,0174 sedangkan kelompok B adalah 0,1217 m 0,0244. Secara statistik p=0,05 terdapat perbedaan signifikan antara kedua kelompok. Kesimpulan: Dapat disimpulkan bahwa tingkat kekasaran permukaan resin komposit nanofilled setelah pemolesan dengan teknik multiple-step lebih baik dibandingkan dengan nanohybrid. ...... Background: Restorative treatment using nanofilled and nanohybrid composite should be finished and polished to reduce surface roughness and create smoother surface of the composite. Objective: To compare the surface roughness nanofilled and nanohybrid composite resin after polishing using multi step technique. Method: 40 composite resin specimens were divided into 2 groups 20 nanofilled specimens Filtek Z350XT A and 20 nanohybrid specimens Filtek Z250XT B was prepared and then polished. After immersion in artificial saliva for 24 hours, the surface roughness is measured with a surface roughness tester. ResultL The mean surface roughness results along with standard deviation of group A is 0,0967 m 0,0174 while group B is 0,1217 m 0,0244. Statistically with p 0.05 , there are significant differences between each group. Conclusion: Surface roughness of nanofilled composite resin after polishing with multiple step technique is better than nanohybrid.