Perbaikan Sistem Perawatan Mesin di PT Gold Coin Indonesia - Medan Mill

Abstract

PT Gold Coin Indonesia Medan-Mill is a company which operates in cattle fodder industry. Its production process often faces obstacles, and one of them is machine breakdown which causes the incidence of downtime of 11.21% or 43.05 hours each month from 2014 until October, 2015. The improvement of machine maintenance can be done to decrease this downtime. Therefore, the title of this research is “Improvement in the System of Machine Maintenance at PT Gold Coin Indonesia – Medan Mill.” Some factors which cause downtime to be high in the company were obtained from the distributed questionnaires. The highest coefficient correlation was found in the 2nd The proposed maintenance system is the schedule for changing spare parts according to the calculation of Total Minimum Downtime. Based on the historical data, it was found that Hammer Mill machine had the highest frequency of damage. The proposed changing interval for Hammer Mill critical component was Beater PCD 80 mm (5x50x150xØ17mm) 288 hours, Screen 695x1120x3DxØ3mm 320 hours, Screen 695x1120x3DxØ8mm) 416 hours, and Hammer Bolt 700-2D 480 hours. factor: the company strategy (decision to change, procurement system, inventory management, and maintenance policy). Maintenance system in this company applies corrective maintenance and preventive maintenance. However, in this maintenance system, the company management only changes damaged components without paying attention to its reliability. Besides that, spare parts should be optimally available in order to support the proposed maintenance system. The result of the calculation of optimal Q for the component of Beater PCD 80 mm (5x50x150xØ17mm) was 1122 units, Screen 695x1120x3DxØ8mm was 22 units, Screen 695x1120x3DxØ8mm was 21 units, and Hammer Bolt 700-2D was 23 units. Meanwhile, the number of the available safeguards for Beater PCD 80mm (5x50x150xØ17mm) component was 75 units, Screen 695x1120x3DxØ3mm was 1 unit, Screen 695x1120x3DxØ8mm was 1 unit, and Hammer Bolt 700-2D was 2 units. The implementation of the proposed maintenance system had significant decrease in downtime of 29,97% and the increase in reliability value of 37,05%.

PT Gold Coin Indonesia Medan – Mill merupakan perusahaan yang bergerak dalam industri pakan ternak. Proses produksi pada perusahaan ini sering mengalami kendala seperti adanya kerusakan mesin. Hal ini mengakibatkan terjadinya downtime dengan rata-rata per bulan yang terjadi tahun 2014 sampai Oktober 2015 sebesar 11,21% atau 43,05 jam. Perbaikan sistem perawatan mesin dapat dilakukan untuk mengurangi downtime tersebut.Oleh karena itu, penulis mengambil judul penelitian “Perbaikan Sistem Perawatan Mesin di PT Gold Coin Indonesia – Medan Mill”. Faktor-faktor yang mengakibatkan tingginya downtime pada perusahaan diperoleh dari kuesioner yang telah disebarkan.Koefisien korelasi tertinggi terdapat pada faktor ke-2 yaitu strategi perusahaan (keputusan penggantian, sistem pengadaan, manajemen inventori dan kebijakan maintenance).Sistem perawatan (maintenance) yang berjalan pada perusahaan ini menerapkan metode corrective maintenance dan preventive maintenance.Namun, pada sistem perawatan yang berjalan ini, pihak perusahaan hanya mengganti komponen yang rusak tanpa memperhatikan keandalannya. Sistem perawatan usulan yang diberikan yaitu jadwal penggantian spare part berdasarkan perhitungan Total Minimum Downtime (TMD).Berdasarkan data historis diperoleh mesin Hammer Mill yang mempunyai frekuensi kerusakan paling tinggi. Interval penggantian yang diusulkan untuk komponen kritis Hammer Mill yaitu Beater PCD 80mm (5x50x150xØ17mm) 288 jam, Screen 695x1120x3DxØ3mm 320 jam, Screen 695x1120x3DxØ8mm 416 jam dan Hammer Bolt 700-2D 480 jam. Selain itu, untuk mendukung sistem perawatan yang diusulkan maka diperlukan persediaan spare part yang optimal. Hasil perhitungan diperoleh Q optimal untuk komponen Beater PCD 80mm (5x50x150xØ17mm) sebanyak 1122 unit, Screen 695x1120x3DxØ3mm sebanyak 22 unit, Screen 695x1120x3DxØ8mm sebanyak 21 unit dan Hammer Bolt 700-2D sebanyak 23 unit. Sedangkan jumlah persediaan pengaman diperoleh untuk komponen Beater PCD 80mm (5x50x150xØ17mm) sebanyak 75 unit, Screen 695x1120x3DxØ3mm sebanyak 1 unit, Screen 695x1120x3DxØ8mm sebanyak 1 unit dan Hammer Bolt 700-2D sebanyak 2 unit. Dengan menerapkan sistem perawatan usulan terjadi penurunan downtime pada perusahaan yang cukup signifikan sebesar 29,97% dan peningkatan nilai keandalan (reliability) sebesar 37,05%.