Diagnostics of crack formation in castings using the logic of plausible reasoning

摘要

Purpose: Cold cracks are the defect often encountered in castings. Quick diagnosis of the cause of crack formation enables preventing the formation of other cracks in the next casting process and enables also, as far as it is possible, a repair of the existing defect. In this task expert systems are a very useful tool. Design/methodology/approach: Standard of Casting Defects elaborated in Poland, Atlas of Casting Defects elaborated in France, and a Review of Casting Defects elaborated in the Czech Republic. These sources are the knowledge compendium of casting defects. Basing on such information, serving as a defect description, the cause of the defect formation and the way of preventing it have been created as formalisms which enable an inference to be carried out, the aim of which is to establish the cause of the defect. Findings: The use of LPR (the Logic of Plausible Reasoning) in the representation of knowledge about casting defects introduces a new quality, allowing to take into consideration the specific characteristics of this knowledge such as: uncertainty, definitions hierarchy, the possibility of introducing the diagnostics ranking. In consequence, the diagnostic process becomes more flexible and may be better adjusted to the real technological process conditions. Practical implications: The efficiency of an expert system diagnosis depends on the data entered previously and on the way in which the knowledge is represented. Originality/value: In this article various representations of the knowledge have been presented by means of the logic of plausible reasoning.