Expert Maintenance System for Life Cycle Assessment of Heavy Machinery

Abstract

The paper provides a brief overview of the research areas of heavy machinery through maintenance models. It is not meant to be a complete review of maintenance models but rather as an informative introduction to important maintenance models. The paper is concerned with the basic preventive maintenance policies arising in the context of heavy machinery maintenance. The investigation in this paper relates mainly to develop preventive replacement model and fault tree analysis for the horizontal boring machine and to reduce the down-time of the machine. Simple but practically important preventive maintenance optimization models, which involve age replacement and block replacement, are reviewed in the framework of the expert maintenance policy. The study was carried out in a mechanical workshop of an engineering construction company in a private sector. There are different machines and hand tools such as Bending machine, CNC Profile cutting machine, vertical turning and boring, horizontal turning and Boring, Gear hobbling machine, Lathe machine, Milling Machine, Plano miller, Planner machine, Grinding Machine, Press, Shearing Machine, hammers and area repair shops equipments. Since the concern was on machining of construction equipment so the study was concentrated on Horizontal & Vertical Turing and Boring. The study was carried out with the following objectives - To develop the methodology for maintenance policies in a job order shop industry due to ill maintenance and to apply fault tree analysis for the development of maintenance policies and expert system. The paper also analyzes the facts of a case study in order to find optimal cost of repair/replacement for finite horizon replacement model when preventive maintenance is imperfect. The maintenance technique used for the analysis of this case study is simple and is based on the statistical calculation of total down time, mean time to repair, mean time between failure and fault tree analysis. Based on these studies an expert system is developed. Financial impact of these studies are also taken into consideration.