cover
Contact Name
Lovely Son
Contact Email
lovelyson@eng.unand.ac.id
Phone
+6281213552846
Journal Mail Official
metal@eng.unand.ac.id
Editorial Address
Kampus Limau Manis, Jurusan Teknik Mesin, Fakultas Teknik, Universitas Andalas
Location
Kota padang,
Sumatera barat
INDONESIA
METAL : Jurnal Sistem Mekanik dan Termal
Published by Universitas Andalas
ISSN : 25981137     EISSN : 25974483     DOI : -
METAL: Jurnal Sistem Mekanik dan Termal translated as METAL: Journal of Systems in Mechanical and Thermal is a scholarly peer-reviewed journal published by Mechanical Engineering Department of Engineering Faculty at Universitas Andalas, Padang, Indonesia. The journal focused on the mechanics and thermal aspects of the mechanical engineering area, and accepted articles are in these subjects: Energy - Renewable energy - Green industry - Energy conversion Mechanical System Engineering - Solid body mechanics - Machine construction - Vibration and control - Mechatronics - Tribology Production System Manufacturing engineering - Product design and development - Production technology - Production logistics and transportation Materials Engineering - Material technology - Nanotechnology
Articles 143 Documents
The Manufacturing Process of Aluminum Hammer Molding using CNC 3 Axis for Waste Plastic in the Injection Molding Machine H, Hendra; Reski Septiana; Dio Restu Putra Ardhika; Hernadewita; Rahmayetty; Rispandi; Hermiyetti; Gusri Akhyar
METAL: Jurnal Sistem Mekanik dan Termal Vol. 9 No. 2 (2025): Jurnal Sistem Mekanik dan Termal (METAL)
Publisher : Department of Mechanical Engineering, Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/metal.9.2.139-145.2025

Abstract

A process called injection molding involves cooling molten plastic after it has been injected into a mold to create a finished product. Polypropylene (PP) and polyethylene terephthalate (PETE), two basic ingredients used in plastic, are melted into a liquid and then injected into a mold. tests pertaining to the geometry of the molded product's shape and the mold's resistance at 150 °C. The mold material used in this study is aluminum 6061, and the techniques used are modeling and experimentation. The 6061-aluminum material has good temperature resistance and yields dimensional results, thickness, and shape that are almost identical to the design developed based on geometry features, which makes it suitable for use in the plastic injection process, according to the test findings.
Optimizing R&D to Enhance Local Content (TKDN) in Electric Motor Components for National Industry Independence herman, pudimirama; Hendra; Hamdan Akbar Notonegoro; Reski Septiana; Rispandi
METAL: Jurnal Sistem Mekanik dan Termal Vol. 9 No. 2 (2025): Jurnal Sistem Mekanik dan Termal (METAL)
Publisher : Department of Mechanical Engineering, Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/metal.9.2.158-165.2025

Abstract

The electric motor industry in Indonesia is a strategic sector that plays a vital role in supporting national economic development. However, challenges in improving competitiveness—particularly regarding the use of local components—remain a major obstacle. Therefore, strengthening the Domestic Component Level (TKDN) is essential as an effort to increase industrial self-reliance, strengthen the local economy, and reduce dependence on imports [1].This study aims to calculate and analyze the TKDN component level of electric motor products and evaluate its impact on the development of local industries and national economic growth. Furthermore, the study seeks to provide strategic recommendations for sustainably increasing TKDN in the future. The research methods include literature review, regulatory analysis, and the collection and analysis of primary data from relevant industry stakeholders. This research adopts a case study approach focused on the automotive sector, with emphasis on actual conditions in Indonesia, referring to Government Regulation No. 28 of 2024. The expected outcomes include: (1) a documented TKDN component level calculation, and (2) policy recommendations for enhancing TKDN that support the development of local technology. It is expected that the results of this study will encourage national industrial independence, expand employment opportunities, and enhance the global competitiveness of locally produced goods.
Bolted Joint Loosening Analysis Due to Structural Vibrations using Short-Time Fourier Transform and Wavelet Transform Rahmatsyah Maksum Ramsi; Meifal Rusli; Feblil Huda
METAL: Jurnal Sistem Mekanik dan Termal Vol. 9 No. 2 (2025): Jurnal Sistem Mekanik dan Termal (METAL)
Publisher : Department of Mechanical Engineering, Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/metal.9.2.130-138.2025

Abstract

This research investigates the influence of bolt loosening on the dynamic behavior of a steel beam structure under continuous vibration excitation for 30 minutes. Bolted joints play a critical role in maintaining structural integrity; however, loosening caused by vibration remains one of the most common failure mechanisms in mechanical structures. To capture the effect of bolt loosening, acceleration responses were analyzed using time-domain inspection, Fast Fourier Transform (FFT), Short-Time Fourier Transform (STFT), and Continuous Wavelet Transform (CWT). The experimental setup involved controlled vibration excitation applied to a steel beam with bolted connections, and response signals were recorded at different stages of loosening progression. The time-domain analysis showed a gradual reduction in acceleration amplitude as bolt tightness decreased, indicating energy dissipation and stiffness loss. FFT provided an overview of frequency content but lacked sensitivity to localized variations. STFT and CWT enabled a more detailed examination of the time-frequency domain, revealing a loss of high-frequency components and significant redistribution of energy patterns during the loosening process. Both methods successfully identified shifts in natural frequencies and variations in response amplitude. Especially, CWT exhibited superior resolution in detecting early-stage loosening compared to STFT, making it more effective for practical monitoring applications. These results highlight the potential of time-frequency analysis as a diagnostic tool for vibration-based Structural Health Monitoring (SHM) systems. Early detection of bolt loosening through non-destructive vibration analysis can improve safety, reduce maintenance costs, and extend the service life of mechanical structures.