Distinctiveness of Initial Preform Properties in Renovation

• Main Authors: V. M. Yaroslavtsev, N. A. Yaroslavtseva
• Format: Article
• Language: Russian
• Published: MGTU im. N.È. Baumana 2015-01-01
• Series: Nauka i Obrazovanie
• Subjects: renovation; individuality properties; preform; life cycle; heredity life cycle; the initial preform; technological heredity; the anisotropy of the properties; the intensity of the cutting process
• Online Access: http://technomag.edu.ru/jour/article/view/308

<p>Technologies of renovation form a special group of resource-and energy saving technological processes as they are, by definition, already aimed either at increasing resource of the objects satisfying needs of the society life support and practical activities in different spheres, or at extension of their life cycle including a reuse of material from which they are made. Renovation is used where there is a material object, which does not meet requirements of standard or technical documentation.</p><p>A characteristic feature of the renovation technologies is lack of procedure for a choice of the preform as in all cases an initial preform is the renovation object itself. Thus each object, acting as an initial preform, has the exclusively individual properties, including technological ones.</p><p>Distinctiveness of renovation object properties is correlated, first of all, with the personified conditions of formation and (or) change of condition of their properties in time at all stages of life cycle (production – transportation – warehousing – operation) starting with a preform material when manufacturing under all types of loadings (technological and operational). As a result each object forms its "history" of loading and damages and, therefore, its information base which has to consider the phenomenon of “heredity of life cycle”. The term "heredity of life cycle" characterizes information support of object at any moment under review, including both information of technological inheritance, and data of operational heredity.</p><p>As a result at every moment of time we have a product with a set of new, uncertain properties caused by the phenomena of heredity of life cycle. These properties are individual for each object to be renovated, which changed its status for the status of initial preform for different types of renovation technologies. This is one of the most important distinctions of renovation technology from the technology used to manufacture a new product where the initial condition of material to produce the same-named details differs within the narrow standards-set limits.</p><p>Technological process of renovation has to ensure restoration of all properties necessary to provide the subsequent operation and demanded work resource of the technical object turned to be an initial preform. The object, which is off-specifications and off-technical regulatory documents, in this case is a carrier of the hereditary information of life cycle, that it have saved up by the time of renovation. This information represents basic data to make decisions on possibility and efficiency of carrying out renovation works, defining their amounts, selecting technological methods of processing, their rational sequence, and means of technological support of the product quality.</p><p>In this regard technological support of quality and work-related properties of the renovated objects directly depends on the knowledge of those properties of initial preform which will be imparted from one technological operation to the other at all stages of the route technology. Thus it is important to take into consideration that a product processed by each previous method with a complex of its output characteristics and properties is the preform for the subsequent method and itself conveys effect of the life cycle heredity of a product by the time under consideration. For example, the available results of pilot studies show that the strain structural anisotropy of material occurring after processing by pressure, rolling in particular, results in strain anisotropy of cutting process.</p><p>Thus strain anisotropy of the main component of the cutting force Pz , can be of ~ 8-10%. Thus, high heterogeneity of properties of renovated objects with the same name, purpose, and application demands an individual approach to each of them, i.e. the corresponding correction of operation conditions, fast readjustment of technological system, and change of other processing conditions.</p>