Shell making method for deep blind hole of precision casting

Abstract

The invention discloses a shell making method for a deep blind hole of a precision casting. The method comprises the following steps of: making a wax pattern module; coating the module to make a shell; sequentially coating a surface layer, a transition layer, a third layer and a fourth layer; after coating the third layer or fourth layer, performing air drying until the shell is completely dried; stirring silica sol zircon powder slurry and mullite sand according to a mass ratio of 4:(6-6.5) into paste to obtain filling; pouring the filling into the position of the deep blind hole of the casting; then aligning the deep blind hole of the casting with a fan for forced air drying until the deep blind hole of the casting is completely dried; continuously reinforcing according to the casting size until the required layer number of the shell is obtained; and dewaxing to obtain a corresponding shell. The shell making method for a deep blind hole of a precision casting, disclosed by the invention, is simple and convenient to operate, effectively solves the difficulty in shell making for a shell deep blind hole of a precision casting, enhances the strength of the shell at the deep blind hole, greatly reduces the defects of breakage, deviation and the like of the shell at the deep blind hole, realizes an obvious effect and fundamentally guarantees the delivery time of the products for customers.

Description

technical field [0001] The invention belongs to the field of investment precision casting, in particular to a shell-making method for deep blind holes of precision castings. Background technique [0002] At present, the shell-making method for deep blind holes in precision castings is: make two surface layers of slurry sand, use silica sol zircon powder slurry to sprinkle 80-120 mesh zircon sand; two transition layers of slurry sand, use silica sol molybdenum The stone powder slurry is sprinkled with 30-60 mesh mullite sand. Before making the second surface layer and the two transition layers, soak in silica sol to fully wet the module, and dry the deep blind hole of the mold shell against the strong wind of the fan for ≥12 hours. After the mold shell is completely dry, use a surface layer of 80-120 mesh The zircon sand fills the deep blind hole, and the mouth is sealed with mullite powder to prevent the zircon sand poured into the deep blind hole from falling off. This ki...

AI Technical Summary

Problems solved by technology

This kind of shell-making process has poor strength at the deep blind hole of the shell, and the shell has extremely high requirements on the level of dewaxing. It is very easy to cause the shell at the deep blind hole to break from the mouth of the blind hole after dewaxing, and the scrap rate of the shell is as high as 70%. %, seriously affecting product delivery

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