Measurment of pressure and deformation of LFC patterns in dry sand molds

摘要

The vibratory compaction of dry sands is one of the principal procedures for the lost foam casting (LFC) process. The sand fills all internal pattern cavities and packs tightly around the coated and dried foam patterns to provide support. The pressure produced during vibration is deemed important, since its uneven distribution may result in undesirable deformation of the foam pattern. Pattern deformation affects the dimensional precision and accuracy of the castings. In this paper, a specially designed sensor is used to measure the sand pressure in the mold. The pressure produced by dry sands is defined as vertical-downward pressure, vertical-upward pressure, and horizontal pressure. The experimental results of the pressure in different directions, and the effects of main influence factors, such as vibrating direction, vibrating time, vibrating dimensions, sand types, are illustrated. Meanwhile, a laboratory study of the mechanical characteristics and deformation of the foam patterns is undertaken. The aim of the research is to obtain the information needed to understand the LFC process in detail and advise foundry production.