Preventive Maintenance untuk Reduksi Downtime Mesin Straightener di PT Krakatau Baja Konstruksi

Abstract

Abstract. Smooth production processes are essential for manufacturing companies to maintain stable and sustainable operations. Machine reliability is a critical factor influencing production performance; therefore, an effective maintenance strategy is required to minimize downtime and unplanned maintenance costs. This study aims to reduce downtime, improve machine reliability, and lower maintenance costs through the implementation of a preventive maintenance strategy on the Straightener machine at PT Krakatau Baja Konstruksi. A quantitative research method was employed using the Straightener machine as the research object. Secondary data consisting of machine failure history and repair time records were analyzed using statistical methods, including the index of fit to determine the failure time distribution and the calculation of Mean Time to Failure (MTTF). The results indicate that the hydraulic cylinder follows a Weibull distribution with an MTTF of 1,075.461 hours, while the straightening roll follows a Lognormal distribution with an MTTF of 853.450 hours. The implementation of preventive maintenance with an optimal maintenance interval of 297 hours significantly reduced maintenance costs from IDR 16,358,433,569 to IDR 2,881,529,598, increased machine reliability to approximately 95%, and substantially reduced downtime compared to the existing maintenance system.

Abstrak. Kelancaran proses produksi merupakan faktor penting dalam menjaga keberlanjutan operasi perusahaan manufaktur. Keandalan mesin menjadi salah satu penentu utama kinerja produksi, sehingga diperlukan strategi pemeliharaan yang efektif untuk meminimalkan downtime dan biaya pemeliharaan tidak terencana. Penelitian ini bertujuan untuk meningkatkan keandalan mesin serta menurunkan downtime dan biaya pemeliharaan melalui penerapan strategi preventive maintenance pada mesin Straightener di PT Krakatau Baja Konstruksi. Metode penelitian kuantitatif digunakan dengan memanfaatkan data sekunder berupa riwayat kerusakan dan waktu perbaikan mesin. Data dianalisis menggunakan metode statistik, termasuk index of fit untuk menentukan distribusi waktu kerusakan serta perhitungan Mean Time to Failure (MTTF). Hasil analisis menunjukkan bahwa silinder hidrolik mengikuti distribusi Weibull dengan MTTF sebesar 1.075,461 jam, sedangkan rol pelurus mengikuti distribusi Lognormal dengan MTTF sebesar 853,450 jam. Penerapan preventive maintenance dengan interval perawatan optimal 297 jam mampu menurunkan biaya pemeliharaan secara signifikan dari Rp 16.358.433.569 menjadi Rp 2.881.529.598, meningkatkan keandalan mesin hingga sekitar 95%, serta mengurangi downtime secara signifikan dibandingkan dengan sistem pemeliharaan sebelumnya.