Identifikasi Faktor Penyebab Cacat Potong Rangka Besi Menggunakan Fault Tree Analysis di PT. LXX

Abstract

Penelitian ini membahas permasalahan kecacatan pada proses pemotongan rangka besi di PT. LXX yang dilakukan menggunakan mesin plasma cutting. Permasalahan utama yang ditemukan adalah jumlah produk cacat yang masih melebihi standar toleransi perusahaan. Berdasarkan data produksi selama periode pengamatan, persentase kecacatan tercatat rata-rata sebesar 7%, sedangkan batas toleransi perusahaan ditetapkan sebesar 3%. Penelitian dilakukan untuk mengetahui faktor-faktor yang memengaruhi munculnya cacat pemotongan serta menentukan penyebab yang paling dominan. Pengumpulan data dilakukan melalui pengamatan langsung di area produksi, wawancara dengan operator, dokumentasi lapangan, dan penelaahan data produksi perusahaan. Faktor penyebab kemudian dianalisis menggunakan fishbone diagram dan dilanjutkan dengan Fault Tree Analysis untuk menelusuri akar penyebab permasalahan. Hasil analisis menunjukkan bahwa kecacatan dipengaruhi oleh faktor operator, mesin, material, dan metode kerja. Beberapa penyebab yang paling dominan meliputi kondisi nozzle, sistem pendingin mesin, kondisi bahan baku, serta pelaksanaan prosedur kerja di area produksi. Berdasarkan hasil tersebut, disusun beberapa rekomendasi perbaikan yang difokuskan pada perawatan mesin, pengawasan proses kerja, evaluasi prosedur, dan pemeriksaan material sebelum digunakan.

This research focuses on defects occurring in the steel frame cutting process at PT. LXX using a plasma cutting machine. The main issue identified was the defect rate, which remained higher than the company’s acceptable standard. Based on production records, the average defect percentage reached 7%, while the allowable limit was 3%. The purpose of this research was to identify the factors causing cutting defects and determine the most dominant root causes. Data were collected through direct observation, operator interviews, production documentation, and company production records. The identified causes were analyzed using a fishbone diagram and then evaluated further with Fault Tree Analysis. The findings indicate that defects were associated with operator performance, machine condition, raw material quality, and work procedures. The dominant causes included nozzle condition, cooling system performance, material condition, and implementation of production procedures. Based on the analysis, several improvement actions were proposed, including routine machine checking, process monitoring, procedure evaluation, and inspection of materials before production.