Pre-foaming method for lost foam casting

Abstract

The invention belongs to the technical field of die manufacturing and in particular relates to a pre-foaming method for lost foam casting. The pre-foaming method for lost foam casting is completed bymatching with a lost foam casting pre-foaming device. The pre-foaming method specifically comprises the following steps of S1, drying foam beads: starting a driving motor and a rotating motor, electrifying a heating wire, and feeding the pre-foamed foam beads by a feeding disc to a drying shell through a first feed inlet to be dried; S2, filtering the foam beads: feeding the foam beads dried by the drying mechanism through a filtering mechanism to collect fine fragments attached to the surfaces of the foam beads by the filtering mechanism; and S3, separating the foam beads: feeding the foam beads filtered by the filtering mechanism into a separating mechanism to separate the foam beads in stages by the separating mechanism according to volume. The pre-foaming method for lost foam casting can be used for removing the fine fragments attached to the surfaces of the foam beads and drying the foam beads fully and separating the foam beads in three stages, so that the integral strength of lost foam is improved.

Description

technical field [0001] The invention belongs to the technical field of mold manufacturing, and in particular relates to a pre-foaming method for lost foam casting. Background technique [0002] Lost foam casting, also known as solid casting, is to bond and combine foam models similar in size and shape to castings to form a model cluster. After brushing with refractory paint and drying, it is buried in dry quartz sand for vibration molding, and poured under negative pressure. A new casting method in which the model is vaporized, the liquid metal occupies the position of the model, solidifies and cools to form a casting. In lost foam casting, the manufacture of foam models is a very critical issue. Expandable beads must be pre-foamed before foam molding. Pre-foaming is a key process that determines the density and formability of the model. A low-boiling hydrocarbon is added to the foam beads as a blowing agent. Under the condition of heating and pressure, the blowing agent ...

AI Technical Summary

Problems solved by technology

In actual production, it is found that this method has the following problems: (1) fine chips will be produced during the pre-expansion process of the foam beads, and the chips adhere to the surface of the foam beads and are formed during aging and secondary foaming. During the process, it is filled between adjacent foam beads, resulting in the loss of the overall strength of the lost foam; (2) the volume of the foam beads is different after pre-expansion, and the direct aging and secondary foaming will lead to the loss of each part of the lost foam. There are differences in the strength of some parts, and variability during transportation and storage; (3) The surface temperature of the foam beads is high after the pre-expansion process, and the moisture in the air will form a thin water film on the surface of the foam beads. It will also affect the overall strength of the lost foam

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