JTRM (Jurnal Teknologi dan Rekayasa Manufaktur)

Experimental Study of Retrofitting R-134a to R-600a on Cold Handling Unit System Performance

Listya Utari — 2026-04-29

The refrigeration industry continues to grow amid global challenges related to the environmental impact of refrigerant use. One of the commonly used refrigerants today is R-134a, but this refrigerant has a global warming potential (GWP) of 1430. As an alternative, R-600a is considered because it has a very low GWP of only 3, and has good compatibility with R-134a-based systems. This study aims to analyze the performance of the refrigeration system after retrofitting from R-134a to R-600a. Tests were conducted at two condensing temperature variations: 33.29°C and 35.29°C. The results show that at 33.29°C, COP increased by 30%, efficiency increased by 12%, and electricity consumption decreased by 32%. At 35.29°C, COP increased by 22%, efficiency by 6%, and electricity consumption decreased by 30%. In addition, R-600a requires only 50% of the refrigerant mass compared to R-134a. A temperature of 33.29°C was considered the optimal condition with the best performance and faster cooling time. These results support the potential of R-600a as an environmentally friendly alternative refrigerant.

Perancangan Mesin Angkat Sampah dengan Sistem Ladder Hoist untuk Aliran Sungai Kecil Berbasis Metode VDI 2222

Dafa Raihan Putra Hamdani — 2026-04-29

Permasalahan pencemaran sungai akibat penumpukan sampah, khususnya di aliran sungai kecil perkotaan seperti di Kota Bandung, masih menjadi isu lingkungan yang signifikan. Aktivitas pengangkutan sampah yang selama ini dilakukan secara manual dinilai kurang efisien karena membutuhkan tenaga besar, waktu lama, dan rentan membahayakan petugas. Untuk menjawab permasalahan ini, dilakukan perancangan mesin angkat sampah dengan sistem ladder hoist menggunakan pendekatan metode VDI 2222. Tahapan perancangan meliputi identifikasi masalah, pengumpulan data lapangan melalui observasi dan wawancara, pengembangan konsep fungsi dan subfungsi, evaluasi alternatif, serta analisis konstruksi dan perhitungan teknis. Mesin dirancang memiliki kapasitas angkut maksimal 140 kg, mampu mengangkat 2–4 karung sampah per siklus, dan dapat digunakan pada sungai dengan tinggi tebing 2–5 meter. Sistem pengangkat menggunakan motor listrik DC berbasis aki dan struktur rangka galvanis yang dapat dibongkar pasang secara modular. Hasil akhir dari perancangan menunjukkan bahwa mesin ini dapat meningkatkan efisiensi proses pengangkatan sampah hingga lebih dari 2 kali lipat dibandingkan metode manual, serta dapat direalisasikan menggunakan komponen lokal yang tersedia di dalam negeri. Dengan desain yang ringkas, portabel, dan berbasis sistem mekanis sederhana, mesin ini diharapkan menjadi solusi aplikatif dalam mendukung kegiatan pembersihan sungai secara berkelanjutan.

Redesign of the Supra Motorcycle Drum Brake Using Reverse Engineering Method with Von Mises Analysis

Hanandira Wistikhirana — 2026-04-29

This study presents a redesign of the drum brake system on a Honda Supra motorcycle using a reverse engineering approach. Innovation was carried out by utilizing aluminum alloy as the brake shoe material to reduce weight and enhance corrosion resistance. In addition, a Non-Asbestos Organic (NAO) brake lining was applied, known for its high friction performance and excellent wear resistance. Design modifications include increasing the rib thickness of the brake shoe to reduce stress concentration and adding a chamfered surface to the brake lining, with a thickness of 5 mm. Structural strength was evaluated through Finite Element Analysis (FEA), using von Mises stress as the performance indicator. The results indicate that the redesigned structure and material successfully reduce stress concentration.

Perancangan Drilling Jig Fixture untuk Flange Drum Spinner di PT. Melu Bangun Wiweka

Meri Rahmi — 2026-04-29

The tire manufacturing process involves a critical building stage using a drum spinner machine, which requires a flange to connect the drum and frame at PT. Melu Bangun Wiweka experienced frequent misalignment issues due to the manual drilling of flange holes. To solve this, a drilling jig fixture was developed to ensure accurate hole placement. Made from SS400, a material known for its good machinability under manual conditions, the fixture measures 303 × 400 × 500 mm. Its implementation significantly reduced drilling time from 21.67 minutes to 8.17 minutes. The estimated manufacturing cost of the fixture is IDR 12,097,097. By using this fixture, the company can save approximately IDR 6,436,000 per month when producing 1,000 units. A cost analysis reveals that the (BEP) is reached at 1,879 units, with each unit priced at IDR 17,807. This innovation improves efficiency, ensures precision, and offers significant cost savings in the long term.

Design of Regenerative Braking Control for Autonomous Trams Using The System Identification Method

Azarya Pramayudo — 2026-04-29

Trams are transportation vehicles that fall under the category of Light Rail Vehicles (LRV), operating in urban areas and connecting different regions within a large metropolitan environment. Tram tracks differ from conventional railways, as they typically consist of dedicated lanes located on or adjacent to roadways, often with specific barriers in place. This condition presents a new challenge, as autonomous trams must be able to adapt to this dynamic environment. This study aims to develop a control system that considers passenger comfort, particularly during braking or deceleration in specific situations and conditions. The System Identification method is chosen to analyze the system's real response to a given input, with the identification results used to design the controller. The identification results and control design were then tested using MATLAB to evaluate the performance of the designed control system in providing a comfortable deceleration experience for passengers. The design results indicate that the control system can regulate torque variations while maintaining acceleration and its rate of change within safe limits.