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All Journal DINAMIKA Jurnal Ilmiah Teknik Mesin International Journal of Engineering, Science and Information Technology Jurnal Sains dan Teknologi
Harjuma Harjuma
Akademi Teknik Soroako
Aerospace Engineering Agriculture, Biological Sciences & Forestry Astronomy Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Dentistry Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Engineering Health Professions Industrial & Manufacturing Engineering Library & Information Science Materials Science & Nanotechnology Mathematics Mechanical Engineering Medicine & Pharmacology Nursing Physics Public Health Social Sciences Transportation Veterinary

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ANALISIS PENGARUH VARIASI TEMPERATUR BAJA AISI 1018 TERHADAP KEKERASAN DENGAN METODE JOMINY TEST Harjuma Harjuma; Simon Parekke
Dinamika : Jurnal Ilmiah Teknik Mesin Vol 10, No 2 (2019)
Publisher : Jurusan Teknik Mesin, Universitas Halu Oleo

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (153.329 KB) | DOI: 10.33772/djitm.v10i2.6954

Abstract

Hardenability of steel is an important guide to determine the pattern of heat behavior and the nature of the material to be heat-treated in the production of components. One way to determine steel hardenability is by using Jominy test method. This study aims to determine the hardness of the AISI 1018 steel by varying temperature in heat treatment. Hardness test was conducted using the Rockwell method (HRA) by varying the heating temperature to 700 °C, 800 °C and 900 °C. The material used was AISI 1018 steel and water as a cooling medium. The standard for making specimens refers to the ASTM A 255 Jominy Test with the following dimension: length of specimen 101.6 mm x diameter of specimen 25.4 mm. Electric heating furnace was used to heat the specimen according to the desired temperature. After a 15-minute holding time, the specimen was then cooled in clean water as cooling medium using Jominy test apparatus. Each specimen was cooled by spraying clean water onto it for 10 minutes. The results showed that the maximum hardness value occurred at the end of the specimen closest to the center of the spray and that the hardness decreased as the distance from the tip of the specimen increased. The results also showed that the higher the given heating temperature, the higher the hardness value of the specimens. However, the increase in temperature does not have a significant effect. This was probably the result of improper selection of materials where the heat treatment requires that the specimen contains more than 0,3% carbon. The specimen was too long on the air when released from the furnace. Hardness of test results obtained at temperature at a heating temperature of 700 ° C the average hardness value was 48.72 kg / mm2, at a temperature heating of 800 ° C the average hardness value was 47.44 kg / mm2 and at a heating temperature of 900 ° C the average hardness value was 48.12 kg/mm2. 
Prototype Perkakas Mekanik Berbasis Benda Kerja Praktik Mahasiswa Abdul Tahir; Edi Rande Padang; Harjuma Harjuma; Fitriana Firdaus
INSOLOGI: Jurnal Sains dan Teknologi Vol. 2 No. 1 (2023): Februari 2023
Publisher : Yayasan Literasi Sains Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55123/insologi.v2i1.1655

Abstract

The learning process for vocational higher education applies a composition of 30 percent theory and 70 percent practice. A larger composition of practical learning will guarantee an increase in the quality of students' expertise, because in practical learning students practice in workshops that produce workpieces in the form of products that have economic value. Workpieces are made by manufacturing processes using industrial-based machines such as lathes, milling machines, drills, grinders, and others. Practical work in the workshop is carried out for one week or the equivalent of 38 hours. The quality of the workpiece is also a parameter for student assessment which will become one of the semester graduation requirements so as to produce quality students in their fields. However, there are problems in practicum activities in the vocational field that are most experienced by almost all vocational education institutions, namely workpiece waste. Vaccination education managers must think about how to optimize or utilize work objects resulting from student practice. Not a few students' work is ignored or thrown away and not utilized. This is the background of this research. This study aims to make mechanical device products that have economic value by utilizing students' work. The product manufacturing method begins with data collection, planning and drawing, the manufacturing process, assembling, and testing. From the results of the tool making, 4 types of prototype products were obtained, namely table vise, bending tools, C clamps, mini press tools. From the four products made, it can be concluded that the tool manufacturing process went according to plan and optimal results were obtained.
Development of Plastic Shredder Technology to Support Plastic Waste Reduction Harjuma Harjuma; Abdul Tahir; Sirama Sirama; Aswar Aswar
International Journal of Engineering, Science and Information Technology Vol 5, No 1 (2025)
Publisher : Malikussaleh University, Aceh, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52088/ijesty.v5i1.643

Abstract

The plastic waste problem in Indonesia has reached a severe level. Data from the National Waste Management Information System shows that Indonesia produces around 17 million tons of plastic waste yearly. However, only approximately 66.47% of this plastic waste undergoes recycling, with the remainder ending up in landfills or polluting the sea. This condition places Indonesia in second place in the world after China in terms of the amount of plastic waste produced, making it a country with a plastic waste emergency. This article discusses the development of plastic recycling machine technology as a solution to overcome the plastic waste problem in Indonesia. With a production of around 17 million tons of plastic waste per year, Indonesia faces significant challenges in plastic waste management. Low efficiency often constrains the effectiveness of plastic recycling as a solution. Therefore, this study aims to design and improve the efficiency of a plastic shredder machine. This machine uses specially designed rotating blade technology to produce high-precision plastic flakes. Additionally, we have updated the transmission system to reduce vibration and implemented other innovations to enhance the machine's capacity to shred various types of plastic. We expect this machine to decrease greenhouse gas emissions from the recycling process and lower operational costs. This study shows that the developed plastic shredder machine can work effectively and efficiently, meeting the research objectives of producing plastic flakes quickly. Thus, we expect this machine to significantly reduce plastic waste in Indonesia and support environmental conservation efforts.
Co-Authors Aswar Aswar Edi Rande Padang Fitriana Firdaus Simon Parekke Sirama Sirama Tahir, Abdul