Analisa dan Rancangan Keandalan Mesin Thresher Menggunakan Metode Overall Equipment effectiveness, Failure Mode and Effect Analysis dan Fault Tree Analysis

Abstract

Mesin thresher berbentuk horizontal dengan panjang silinder 400 cm, diameter 200 cm dengan kisi-kisi 5 cm sebagai alat pemipil tandan buah sawit dengan cara memutar drum thresher sehingga tandan buah sawit terpipil dan digunakan pada pabrik pengolahan kelapa sawit. Sejauh yang didapat kajian mengenai analisa kekuatan dan tegangan pada arm thresher (penyangga drum thresher) bahwa kegagalan pada thresher terjadi karena kesalahan pada proses pabrikasi dan operasional yang tidak sesuai standar. Sehingga untuk mengetahui tingkat keefektifan dan keandalan dari mesin thresher dianalisa dengan metode Overall Equipment Effectifeness (OEE). Mengkaji tingkat resiko kegagalan komponen pada mesin thresher digunakan metode Failure mode and effect analysis (FMEA) sehingga didapatkan nilai risk priority number (RPN) yang tertinggi pada komponen sebagai penyebab dominan kegagalan yaitu komponen drum thresher, stripper, elektro motor plummer block bearing automatic feeder dan V-belt, untuk menentukan pengaruh kerusakan yang terjadi antar komponen dilakukan uji ANOVA dimana diketahui drum thresher, stripper, elektro motor dan V-belt memiliki nilai varian signifikan terhadap pengaruh terjadinya kegagalan sementara automatic feeder dan plummer block bearing cenderung memiliki pengaruh yang sama terhadap terjadinya kerusakan mesin thresher. Fault tree analysis (FTA) digunakan sebagai analisa perpaduan korelasi fungsi sistem dan kegagalan komponen sehingga dapat diidentifikasi level peluang kegagalan system. Berdasarkan analisa reliability sistem >60% dan dengan jam operasional yang optimal setiap komponen dilakukan pemeliharaan yang terjadwal adalah: 50 jam operasional dilakukan inspeksi pada drum thresher dan stripper, 100 jam opersional dilakukan inspeksi elektro motor, 150 jam dilakukan inspeksi pada automatic feeder, 250 jam dilakukan inspeksi pada V-belt dan 800 jam dilakukan inspeksi pada plummer block bearing. Dengan adanya kajian ini dapat dirancang pencegahan sehingga mengurangi peluang terjadinya breakdown.

Machine thresher is horizontal with a length of 400 cm cylinder, diameter 200 cm by 5 cm grating as palm fruit bunches sheller tool by rotating drum thresher that loosen palm fruit bunches and used in palm oil mills. As far as the study of the analysis obtained on strength and arm thresher (buffer drum threshers) that the failure of the thresher occur because of errors in the manufacturing process and operations that do not fit the standard. So as to determine the level of effectiveness and reliability of the machine thresher analyzed by Effectifeness Overall Equipment (OEE). Assessing the level of risk of component failure on the machine thresher used methods Failure mode and effects analysis (FMEA) to obtain the value of risk priority number (RPN) were highest in the component as the dominant cause of failure is a component drum thresher, stripper, electro motors plummer block bearing, automatic feeder and V-belt, to determine the effect of the damage that occurs between the components performed ANOVA test which is known drum thresher, stripper, electro motors and V-belt has a variance significantly to influence the occurrence of a failure while the automatic feeder and plummer block bearing tend to have the same effect on the occurrence of machine thresher damage. Fault tree analysis (FTA) is used as a blend correlation analysis system function and failure of components in order to identify the level of probability of failure system. Based on the analysis of reliability system > 60% and the operating hours are optimized every component do maintenance scheduled are: 50 operating hours inspection on drums thresher and stripper,100 hours operational inspection of electrical motors, 150-hour inspection on the automatic feeder, 250 hours carried out inspections at the V-belt and 800 hour inspections at the plummer block bearing. With the existence of this study can be designed prevention, thereby reducing the chances of a breakdown.