ENGINEERING JOURNAL: VARIASI KEKERASAN PADA BAJA KARBON RENDAH (St37) AKIBAT PERLAKUAN TEMPERING SETELAH PROSES DOUBLE HARDENING

Jurnal REKAYASA Volume 7 Nomor 2 Artikel 3

Mahros Darsin
(Staf Pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)

Ahmad Effan
(Guru SMK Berdikari Jember, Dosen Luar Biasa Jurusan Teknik Mesin Universitas Muhammadiyah Jember)

Agus Setiawan
(Alumni Jurusan Teknik Mesin Universitas Muhammadiyah Jember)

ABSTRACT: Double hardening is the process of hardening after carburizing process, which ended with the process of tempering. The purpose of the double-hardening process is to improve the structure of the skin together at the core. In this study expected to provide information about changes in the strength of steel resulting from the hardening of steel in a double process of hardening. Materials used in this study is low carbon steel ST 37. Solid cylindrical material with a diameter of 25 mm and a length of 20 mm. Media carburizing using wood charcoal plus ± 40% barium carbonate is carried out at 900 oC with holding time for 4 hours, followed by a double-hardening process at 900 oC and 750 oC with the media water coolers, and then ends the process of tempering with the variation of temperature 180 oC, 250 oC, 300 oC. Vickers hardness test method with weights 50 kg. The value of raw material hardness after carburizing process VHN 547.44. The results were subjected to a double process of carburizing hardening with tempering 180°C has a hardness value 542.54 VHN decreased 0.9%. to the control specimens. While the tempering 250 °C produces violence VHN 442.62, down 23.68% against the control specimens. In the tempering temperature 300 oC has the lowest hardness value 385.15 VHN, declining 42.13% of the control specimens. In the double-hardening process, the resulting structure is cementite, pearlite and ferrite. However, the cementite structure tends to decrease, because it ended with tempers. From this research can be concluded that the control specimen hardness value higher than the double-hardening process, because the control specimen just given carburizing process. The process ends with a double hardening tempering process so as not brittle or fragile. The greater the temperature of tempering steel, the hardness will decrease.

Keywords: carburizing, double hardening, tempering, kekerasan.

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ENGINEERING JOURNAL: STUDI EKSPERIMENTAL PENGARUH PEMASANGAN SIRIP

Jurnal REKAYASA Volume 7 Nomor 2 Artikel 2

Muh Nurkoyim Kustanto
(Staf Pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)

ABSTRACT: The Perfect combustion can improve engine performance and save fuel consumption. One of the requirements perfect combustion is a homogeneous mixture of fuel and air when entering the combustion chamber. Air and fuel mixture to become homogeneous in case of turbulence in the mixing. Buffer with fin-shaped flow director is a tool that serves to provide additional mixing time between air and fuel at the same time create a turbulent flow before entering the combustion chamber. In this study the buffer fitted with fins director with different variations. The number of fins variation used in this study are 3, 4, 6, 8 and 10 with a variation of the angle are 45o and 60o. The analysis was conducted on the effective power and torque output and the FC (Fuel Consumption) needed from each variation condition buffer. From the results of testing on the condition of the buffer with 3 fins angled 60o obtain the highest effective power increase 5.92% and increase in the highest torque 2.66%  when compared with the buffer without fins. The lowest FC (Fuel Consumption) in the buffer with 3 fin angle 60 ° when compared with the buffer without any fins at 4000 rpm with a 11.15% difference.

Keywords:homogeneous, turbulent, buffer, fin

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ENGINEERING JOURNAL: ANALISIS PENGARUH KARAKTERISTIK LINGKUNGAN EKSTERNAL TERHADAP KINERJA SEKOLAH DENGAN PENDEKATAN BALANCED SCORECARD

Jurnal REKAYASA Volume 7 Nomor 2 Artikel 1

Robertus Sidartawan
(Staf Pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)

ABSTRACT: This paper presents the analysis of steady state performance of three-phase induction generator with the capacitance itself berpenguatan not balanced and unbalanced load distribution. Using the method of symmetrical components, load three-phase generator The Schools have to anticipate the influence of external environments. Started at SWOT analysis, The schools  take a position to get a competitive advantage. SWOT used to analyse both the external and internal environment.The external analysis consist of the macro and micro analysis. The macro
analysis consist of the power of politics and laws, the power of technology, and the power of culture socials. The purpose of this study was to examine the external macro environment characteristic on organizational performance of  school in balanced scorecard approach. Data for this study were collected from middle schools using a self-administered survey questionnaire. Hypothesis test showed that the power of politics and laws, the power of technology, and the power  of culture socials examined had a significant impact on school performance in balanced scorecard approach.  but partially only the power of technology are significantly influence on schools performance in balanced scorecard approach. but for  the power of  politics and
laws and the power of culture aren’t significantly influence on schools performance in balanced scorecard approach.

Keywords: external environment,  performance, balanced scorecard

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ENGINEERING JOURNAL : STUDI ERGONOMI PERANCANGAN DAN PENGEMBANGAN PRODUK TONGKAT LANSIA DENGAN METODE QUALITY FUNCTION DEPLOYMENT (QFD)

Jurnal REKAYASA Volume 7 Nomor 1 Artikel 09

Yuni Hermawan
(Staf Pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)

ABSTRACT: Like a machine that with age, the elderly also experienced setbacks function (Degradation of function). One of them, reverses the power balance of body, aids the road was to be one right solution. One is the stick. But stick products sold in Indonesia most imported goods, often times these products are not in accordance with the dimensions of the body of Indonesia. It is necessary for the form of product development efforts that may be evaluating the existing products on the market or create new products, to fit the dimensions of the body of Indonesia. In developing a product other than in terms of body dimensions (anthropometry), objective research to study the process of designing and developing products that involve the consumer so that the results of the design process really answer the needs of the customer.Data collection was conducted through a questionnaire and consumer processed Quality Function Deployment method (QFD), so he found some consumers desire. Based on these consumer desires by creating several concept development. Of the various concepts being developed, and then selected a concept based on criteria such as light, strong, comfortable and can be manufactured. While the strength of the framework are analyzed with the help of CATIA V5R14.
Data processing done to produce 17 attributes and consumer desires to create three-rod concept which will be chosen one. Anthropometric data generated through high-stick the maximum is 884.5 mm, weight is 0.83 kg of cane, the handle rod length is 88 mm and diameter of the handle of the stick is ± 30 mm with maximum load on the rod is 53 N. elderly Seen that the greatest stress occurs is still under the stress of the material itself permits. Stress which occurs in the context of 6.47e +006 N/m2 located on the handle of the stick while the minimum stress acting on the order of 1.29e-008th N/m2 on pipe up. The rod can be separated, in a rod that is made is divided into three parts: the head of the stick, cane stalks and cane leg. Injury risk level value obtained was 2, which shows the attitude of the body is accepted (acceptabel) and need not be changed for the long term.

Keywords: stick, QFD, ergonomic, product design and development

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ENGINEERING JOURNAL : PENGARUH SUDUT PENGAPIAN DAN JENIS BENSIN TERHADAP UNJUK KERJA MOTOR BENSIN 4 LANGKAH

Jurnal Rekayasa Vol 6 No 2 Artikel 07

Muh Nurkoyim Kustanto
(Staf pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)

ABSTRACT: The automotive technology growth very fast, the development need an engine performance optimalization. The engine performance influenced one of fuel properties , different octane number can be used by people for the application to improve engine performance. The application of fuel with a higher octane number was able to avoid self-burning or knocking which is decreasing the engine efficiency and cause engine damages. But in other case higher octane number not effect on engine perpormance for some reason. This research was conducted to comparison of using Premium, Pertamax, and Pertamax Plus that used in same engine that is 4 stroke Datsun GWE 80/100 . This research concerned to know an optimum of engine performance and the exhaust gas emission. The variables used in this research are Premium, Pertamax, and Pertamax Plus with engine rotation variation 1500, 2000, 2500, 3000, and 3500 rpm and an ignition timing variation 12,15, and 18 degrees BTDC. The result of research shows that using Premium as an engine fuel was produce an optimum of engine performance compared to Pertamax and Pertamax optimum ignition timing by the used of Premium on 15 degrees BTDC

Keywords: discrete Fourier transform, digital signal processing

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ENGINEERING JOURNAL : PENINGKATAN MUTU HASIL SAMPING PENGGILINGAN PADI MELALUI PENERAPAN ALSINTAN PASCAPANEN

Jurnal Rekayasa Vol 6 No 1 Artikel 11

Ahmad Syuhri
( Staf Pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)

ABSTRACT: Bran is produced from other side the paddy hulling which its exploiting is used for the raw material of food livestock. Bran quality of result of paddy hulling in Indonesia most still not yet fulfilled the standard required by industry of food livestock. To be made by raw material of food livestock, bran need the process screening, so that productivity of raw material of food livestock specially bran become to lower. To overcome the the problems hence require to be made by hammer mill machine for bran produced from the paddy hulling machine. Research to start from phase of mechanism scheme work, machine component planning, fabrication, assembling, and machine examination. Machine use the electromotor with the power 3 HP; rotation 1600 rpm as driver. Rotation of motor by transmission to roller with V-belt. Rough bran to be refined feed into cavity between rotary roller (rotor) and static roller (stator). Result of machine examination can the function, with measurement produced a bran of the size maximal mesh 30 is 83%. With the existence of this hammer mill machine of bran, can improve the quality, productivity, and continuity of raw material of food livestock.

Keywords : bran, mesh, design, quality, productivity

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ENGINEERING JOURNAL : ANALISIS SIFAT MEKANIK BIOKOMPOSIT LAMINAT SERAT SABUT KELAPA DENGAN RESIN POLIESTER

Jurnal Rekayasa Vol 6 No 1 Artikel 06

Sumarji
(Staf Pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)


ABSTRACT: Coconut coir is result from other side from coconut fruit. Exploiting of coconut coir in this time still very less, evaluated of economic value and also its added value. From technological facet of coconut coir can be exploited upon which composite fiber. This research is executed with a purpose to (a) make laminated composite of coconut coir fiber in the place of synthetic fiber, and (b) test and determine the mechanic properties of laminated composite for the materials engineering. Laminated composites made with combinations of coconut coir fiber and matrix of resin polyester with direction oriented fiber 0o / 90o. Influence of variation of the checked is volume faction of fiber and time treatment of fiber in alkali solution (NaOH) with concentration 5%. Examination mechanical properties of laminated composites done with tensile test which relate ASTM D 638 and test of bending which relate of ASTM C 393 standard. Result of research, the ultimate tensile strength equal to 11,019 MPa at laminated composites with volume faction of fiber equal 12%, and is time of treatment of NaOH 2 hour. The ultimate bending strength equal to 44,640 MPa at laminated composite with volume faction fiber equal 12%, and is time of treatment of NaOH 6 hour. From fracture surface that happened is brittle fracture. Result of micro structure observation happened fiber pull out accompanied with delaminating.

Keywords : coconut coir fiber, laminated composite, mechanic properties.


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ENGINEERING JOURNAL : OPTIMASI KEBULATAN PADA PROSES DRILLING DENGAN VARIASI PARAMETER PEMOTONGAN DAN PAHAT MODIFIKASI

Jurnal Rekayasa Vol 6 No 1 Artikel 05

Yuni Hermawan
(Staf Pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)

ABSTRACT: The quality of product by drilling process depend on the cutting condition, like cutting speed, feeding and dept of cut. In research done to determine the value of parameters process cutting in order to minimize roundness. Parameters process which is taken in this research are cutting speed, feeding and dept of cut. The research using analysis of Varian (ANOVA) and respon surface methodology with approaching the smaller is better. Both of these analysis use to determine the value of parameters process above. The combination of parameter process value which is produce optimal response on tool modified are cutting speed 15 m/min, feeding 0.125 mm/cyc and dept of cut 8.48 mm . These parameter values wil produce roundness 64.74 µm.

Keywords : drilling proceses, roundness and tool modified

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ENGINEERING JOURNAL : PENGEMBANGAN ALSIN PENANAM SISTIM INJEKSI DUA, EMPAT DAN ENAM BARIS UNTUK MENANAM JAGUNG ATAU KEDELAI PADA LAHAN KERING/TEGALAN

Jurnal Rekayasa Vol 5 No 2 Artikel 09

R. Koekoeh Koentjoro Wibowo
( Staf Pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)


ABSTRACT: To pursue goals growth of maize national production and soy, precise technological innovation utilize to plant soy or maize is needed at this time. Composite seed of maize can yield around four to five ton per hectare, whereas seed of hybrid can yield more than seven ton per hectare. While to improve soy crop productivity equal to 3 ton per hectare, there are needed by the effort in various areas. Precise adjustment of technology utilize will assist to improve maize productivity or soy. This research aim to develop seed cultivator of injection systems a one row line become two rows , four rows and six rows to plant soy or maize. Making of roll metering is designed in such a manner till to release maize seed or soy which according to on condition that enough agronomy arranged wide narrow hole him to release seed. The seed cultivator can work to penetrate farm by force ground with minimum mean 489.7 kPa. Pursuant to from result analyzed economical, operating expenses to plant lowest soy or maize among third appliance it is by using seed cultivator of six rows injection systems for soy or maize, that is per the hectare of Rp. 23,402 .

Keywords : penanam injeksi 2,4, dan 6 baris

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ENGINEERING JOURNAL : SIMULASI PENGENDALIAN AKTIF TERHADAP SILINDER SIRKULAR TUNGGAL DENGAN PEMANASAN PERMUKAAN SILINDER PADA FLUKS PANAS TETAP

Jurnal Rekayasa Vol 5 No 2 Artikel 08

Muh Nurkoyim Kustanto
( Staf Pengajar Jurusan Teknik Mesin, Fakultas Teknik, Universitas Jember)

ABSTRACT: Active flow control is one methode to reduce drag coefficient of immersed body through fluid flow. One of active control could be done by warm-up the surface of cylinder. Numerical simulation used ANSYS 11.0 software. Modelling done by warm-up the cylinder surface that place orthogonal and move pass through with 30 m/s velocity and air temperature 200C. Air flow modelled as external flow at pressure 1 atm. The cylinder heated by 3 methode, that is heating all over cylinder surface, half of front cylinder surface dan half of rear cylinder surface. The cylinder without surface heating used as comparation. The cylinder heating by constan flux 500, 750 and 1000 w/m2 successively. The result show that heating cylinder at rear the drag coefficient raise average 0.09%. On the heating all over cylinder surface drag coefficient raise average 0,1 %. at simulation range. On the heating half front cylinder surface raise of drag coefficient happened about 0,19 % at simulation range.

Keywords : Active flow controll, Cylinder surface heating, drag coefficient..

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