ASSESSMENT OF THE EFFICIENCY OF USING BLIND FEEDERS OF VARIOUS GEOMETRY BASED ON MATHEMATICAL SIMULATION RESULTS

A short analysis of existing methods for reducing the feeders’ volume is carried out. Their advantages and disadvantages are singled out. The area of application of optimization methods of the feeders’ form is substantiated with the purpose of increasing the casting yield. The actual location of shrinkage defects in variously designed feeders is considered. The patterns of location and shape of shrinkage cavity are shown depending on the shape of the feeder upper section. This allowed to distinguish four groups of feeders and noted the differences in the effectiveness of their work. To clarify the mechanism of shrinkage defects formation in feeders with a different form of the upper section and to estimate the effectiveness of their work, it is proposed to use methods of mathematical modeling. The appropriateness of using mathematical modeling methods is emphasized, by means of the pos­sibility of idealizing external influencing factors on thermal processes in the form that is difficult to achieve in real conditions of foundry pro­duction. The SOLIDCast application is used as the modeling means. The initial and boundary conditions for mathematical modeling were identical for all types of feeders. The results of the shrinkage cavities prediction are presented as isosurfaces diagrams, the sizes were used for estimation of the feeders work efficiency. The method of estima­tion of variously designed feeders’ effectiveness is proposed on the basis of mathematical modeling results. Characteristics of shrinkage defects location in feeders’ volume are proposed to use for estima­tion of feeder’s effectiveness. Its calculation for the feeders of equal size but having differently designed top part is shown. The introduced efficiency index has a good adjustment with geometric module (ratio between volume and surface of feeder). Increasing feeder’s geometric module increases its thermal efficiency. It is shown that the use of a notch allows to increase feeder’s efficiency. The explanation of mecha­nism of notch thermal behavior and its influence on shrinkage defects location is offered on the basis of analysis of isothermal lines in feed­ers’ cross section. Recommendations towards maximization of casting yield are substantiated due to the change in feeder top part design. The opportunity of increasing of casting yield up to 4% and reducing casting defects by optimization feeder’s upper section shape is shown.