1. Understanding of pre-release density:

For example: STMMA-2# material, we suggest a specific gravity of 19~21g/l. It is that the pre-develop density of any casting should be controlled within this range; the pre-develop density should be reasonably selected according to the structure of different castings the wall thickness of different castings. The upper lower limits of the pre-sending density are sometimes even lower when thick parts lifting feeding. For EPS beads: when the thinnest wall thickness of the casting is ≥7mm, the density of the beads cannot be higher than 20g/l;

2. Quality requirements:

No matter what kind of beads are used, make sure that the pre-issued beads are smooth moisturized. The size of the pre-issued beads is uniform the density fluctuation is small. The density of the produced shape must be basically the same everywhere; in general, the appearance The mass ratio to the casting is about 1:300. (Generally, it is determined according to the size of the casting, the wall thickness, the specifications of the beads the material of the beads).

3. Control of step density:

We require a density step of ±1g/L on the same model. To control this technical index well, we must first conduct in-depth research analysis on the mold the feeding system method; first, consider the mold air plug hole Size position, then consider the position quantity of the feeding port, finally choose the feeding system feeding method. Finally, it is necessary to control the influence of human factors.