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Rifelino
Universitas Negeri Padang

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Analysis of the Effect of Feed Rate, Spindle Speed and Coolant on Surface the Roughness of ST 37 Steel in the Turning Process Rahmatul Fauzan Mulyadi; Syahril; Rifelino; Zainal Abadi
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 2 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/epr1f741

Abstract

Surface roughness is an important parameter in turning processes, as it directly affects the performance and service life of mechanical components. This study aims to examine the influence of feed rate, spindle speed, and coolant application on the estimated surface roughness (Raest) of ST 37 steel under conventional turning conditions. A 2³ full factorial experimental design was employed, involving eight treatment combinations consisting of two feed rate levels (0.040 and 0.100 mm/rev), two spindle speed levels (315 and 400 rpm), and two cooling conditions (with and without coolant). Surface roughness estimation was carried out using digital image analysis with ImageJ software based on optical microscope images. The analysis utilized gray-level intensity distributions, which were then converted into roughness values using an empirical scaling approach. The results indicate that increasing the feed rate led to a rise in Raest ranging from 1.74% to 7.11%, while higher spindle speeds contributed to an increase in surface roughness between 4.54% and 11.91%. In contrast, the use of coolant reduced surface roughness by an average of 9.20%, mainly due to its role in minimizing heat and friction during machining. The optimal parameter combination was obtained at a spindle speed of 315 rpm and a feed rate of 0.040 mm/rev with coolant, producing an Raest value of 1.495 µm, which falls within ISO roughness class N7. Overall, all specimens were classified within ISO N7, indicating a semi-finishing surface quality.
Effect of Rice Husk Ash and Clay Powder as Cooling Media in Post Weld Heat Treatment (PWHT) on The Impact Toughness of SMAW-Welded SS400 Steel Angga Hermawansyah; Zainal Abadi; Delima Yanti Sari; Rifelino
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 2 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/f6gkaq38

Abstract

This study investigates the effect of variations in cooling media during Post Weld Heat Treatment (PWHT) on the impact toughness of low carbon steel SS400. The main problem addressed in this research is how differences in cooling medium characteristics influence the cooling rate, which subsequently affects the impact toughness of welded material. The objective of this study is to determine the effect of using rice husk ash, clay, and air as cooling media on the impact toughness value of SS400 steel. The experimental method was employed by applying PWHT to SMAW-welded specimens, followed by Charpy impact testing to obtain the final deflection angle, which was then converted into impact energy and impact value (HI). The results show that clay cooling medium provides the highest average impact toughness value of 1.175 J/mm², followed by rice husk ash at 1.107 J/mm², while air cooling yields the lowest value of 0.845 J/mm². These differences indicate that the thermal characteristics of the cooling media significantly influence the material’s ability to absorb energy before fracture, which is related to the stability of the cooling rate during the PWHT process. It can be concluded that variations in cooling media affect the impact toughness of SS400 steel, where more stable cooling conditions lead to higher toughness values.
Optimization of Laser Cutting Parameters toward Formation of Dross Defects on Stainless Steel Material Imam Qulugqin Azhim; Rifelino; Syahril; Zainal Abadi
Jurnal Vokasi Mekanika (VoMek) Vol 8 No 3 (2026): Jurnal Vokasi Mekanika
Publisher : Unversitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/w7y55g34

Abstract

Laser cutting technology is widely used in the manufacturing industry because it is able to produce precise and efficient cutting. However, improper setting of cutting parameters can cause the formation of dross defects that reduce the quality of the cut. This research aims to analyze the formation of dross defects and determine the optimal cutting parameters on stainless steel materials with a thickness of 1 mm and a cutting length of 50 mm. The full factorial experimental design is used with three process parameters, namely cutting speed (S), focus point (F), and gas pressure (P). The height of the cutting results is measured and analyzed using the Analysis of Variance (ANOVA) method to evaluate the effect of each parameter on the observed response. The analysis results show that the focus point factor (F) has a significant effect on the dross height with a p-value of 0.029 (<0.05), while cutting speed, gas pressure, and all interactions between factors do not show a statistically significant effect. Contribution analysis shows that the F×P interaction gives the greatest contribution to the dross height variation of 29%, followed by the F factor of 27%. Based on the research results, the combination of optimal parameters to minimize the height of the dross was obtained at the focus point -2 mm, cutting speed 30 m/min, and gas pressure 10 bar. This finding shows that focus point setting is the main factor in controlling dross defects in the laser cutting process of stainless steel materials.