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Analisis Pengaruh Kedalaman Pemakanan terhadap Getaran dan Kekasaran Permukaan dalam Proses Pembubutan Baja AISI 4140 Mudjijanto, Mudjijanto; Achmadi, Ali; Agustino, Agil
SIMETRIS Vol 19 No 1 (2025): SIMETRIS
Publisher : Sekolah Tinggi Teknologi Ronggolawe Cepu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51901/simetris.v19i1.543

Abstract

This research was conducted to evaluate the effect of varying depth of cut on vibration levels and surface roughness during the turning process of AISI 4140 steel. The experiments were carried out using a lathe machine equipped with a carbide cutting tool, a spindle speed of 265 rpm, and a feed rate of 0.1 mm/rev. The depth of cut was varied at 0.5 mm, 1 mm, and 1.5 mm. Experimental results indicated that increasing the depth of cut significantly influenced the rise in vibration and surface roughness values. At a depth of 0.5 mm, the recorded vibration was 0.4 mm/s with a surface roughness (Ra) of 4.074 µm. Meanwhile, at depths of 1 mm and 1.5 mm, vibration increased to 1.1 mm/s and 1.8 mm/s, with surface roughness values of 4.216 µm and 5.758 µm, respectively. These findings suggest that greater depths of cut lead to higher cutting forces, which in turn elevate both vibration and surface roughness. Therefore, selecting appropriate machining parameters is crucial to achieving optimal surface quality in turning processes
CIPP-BASED EVALUATION OF ONE-MONTH TAHFIDZ PROGRAM: INSIGHTS FROM YAYASAN KARANTINA TAHFIZ AL-QUR’AN IN WEST JAVA Achmadi, Ali; Ernawati, Ernawati; Ghani, Abdul Rahman A.; Giyanti, Giyanti
World Psychology Vol. 4 No. 2 (2025)
Publisher : Sekolah Tinggi Agama Islam Al-Hikmah Pariangan Batusangkar, West Sumatra, Indonesia.

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55849/wp.v4i2.1049

Abstract

This research evaluates One-Month Tahfidz Program at Yayasan karantina Tahfidz Nasional (YKTN) in West Java using CIPP Model. Data were collected through observations, interviews, and document study. The findings show that the program vision dan mission are relevant to Muslim society needs, offering opportunities for participants from diverse background. Input such as facilities and qualified instructors are adequate, though pedagogical skills require improvement. The process evaluation highlights the effectiveness of Yadain method and intensive scheduling, yet some participants face fatigue and differing learning styles. Product evaluation indicates significant outcomes: 30% of participants completed 30 Juz, while most achieved 15–25 Juz with an error rate of 2–4% and retention of 96–98%. Overall, the program is effective, but requires follow-up mechanisms to maintain long-term memorization.