RU16347U1 - GATE-VENTILATION SYSTEM FOR PRESSURE CASTING - Google Patents

Abstract

A sprue-ventilation system for injection molding, comprising a sprue sleeve connected to an annular collector for metal, on the outer contour of which there are feeders connecting it to the forming cavities, characterized in that at a distance of not more than 10 thicknesses of the casting wall from the edge of the forming cavity ring air collector connected to the forming cavity by one continuous ventilation duct and to the atmosphere by deep air ducts of square section, total area which are equal to or greater than the total area of the gas outlet from the forming cavity S = P · h, where S is the area of the gas outlet; P is the perimeter of the casting; h is the depth of the ventilation ducts.

Description

Casting and ventilation system for injection molding The solution relates to foundry, in particular to injection molding of metals and alloys.

Known gate-ventilation system for injection molding, which contains an annular collector for metal, on the outer contour of which there are feeders connecting it to the forming cavities, and washers communicating with the forming cavities through the connecting channels and to the atmosphere through the ventilation channels. In addition, the system has additional washers located along the inner contour of the annular collector and connected to the atmosphere (AS USSR No. 1770057, class B 225017/00, 1992).

The disadvantage of this gate-ventilation system is that not all of the perimeter of the casting is used to exhaust gases, but only part of it, since the ventilation ducts are made in the form of slots adjacent to the washer and the presence of additional washers along the inner circuit of the collector increases the metal consumption. As a prototype, an external sprue-ventilation system containing a sprue bushing connected to an annular collector for metal is considered, along the outer contour of which there are feeders connecting it to the forming cavities connected to the washers, from which air and gases are removed through ventilation ducts made in the form of thin wide slots with a depth of b.can.O.C5 2000114097

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MKL6V22D 17/00

0.3 MM in the cavity of the connector, having an outlet to the atmosphere. (Injection molding. M.B. Becker., M.L. Zaslavsky, Yu.F. Ignatenko et al. - 3rd ed., Moscow: Mashinostroenie, 1990.p. 74-75.76, 80).

The disadvantage of this gate-ventilation system is the possibility of gas capture by the pressed metal due to the low efficiency of ventilation through the ventilation channels due to their shallow depth and long extent. The disadvantage is that not all of the perimeter of the casting is used to exhaust gases, but only a small part of it, since the ventilation ducts are made in the form of separate slots adjacent either to the washer or, in its absence, to the casting itself.

The task to be solved is the improvement of the gate-ventilation system to improve the quality of castings.

EFFECT: improved ventilation of the mold and reduction of marriage by gas porosity.

This technical result is achieved by the fact that in a gate-injection system for injection molding containing a gate, connected to an annular collector for metal, on the outer contour of which there are feeders connecting it to the forming cavities, at a distance of not more than 10 thicknesses of the casting wall from the edge of the forming the cavity is made of an annular air collector connected to the forming cavity by one continuous ventilation duct and with the atmosphere by ventilation ducts, the total area dv is equal to or greater than the total area of drainage

gas from the forming cavity. The maximum possible area of gas removal is equal to ROTL ven.can, where SOTB is the area of gas removal, ROTL is the perimeter of the casting, bven.can is the depth of the ventilation duct. This allows you to increase the area of gas exit from the casting to a maximum value, and provides better ventilation for castings of complex configuration. This system can be successfully used for injection molding in multi-cavity molds.

The drawings show a gate-ventilation system for injection molding (Fig. 1 - multi-cavity mold, Fig. 2 - single-cavity mold).

The sprue-ventilation system for injection molding contains a sprue sleeve 1 connected by a feeder 2 to a casting (single-socket) or an annular collector 3 for metal (multi-socket). On the outside of the annular collector 3 for metal, there are feeders 2 and forming cavities 4. The annular air collector 5 is connected to the casting or the outer edge of the sprue collector (multi-hole) by a continuous ventilation duct 6, the depth of which of the bend.can is 0.05 0.3 mm depending on the alloy . The air manifold 5 communicates with the atmosphere through ventilation ducts 7 of rectangular or square cross section. The depth of these channels is equal to the depth of the collector. The number of channels is determined based on the technical and technological conditions for the design of the mold. To ensure efficient operation of the ring air manifold, it should be as close as possible

to the forming cavity. The minimum distance is determined from the condition of the wall strength between the air collector and the forming cavity at the working temperature of the casting of the alloy, and at a distance of more than 10 thicknesses of the casting wall due to the large length of the continuous ventilation duct and the hydraulic resistance forces arising in it, the use of an annular air collector loses the smele, since air removal becomes difficult.

Gate-ventilation system for injection molding works as follows.

In the process of pressing liquid metal through the sprue sleeve 1 and the feeder 2 enters the annular collector 3 for metal. At the initial moment of filling this collector 3 with liquid metal, part of the gases is removed through the ventilation duct 6 to the air collector 5 and then released into the atmosphere through the ventilation ducts 7. After the annular collector 3 for metal is completely filled with the melt through the feeders 2, the metal enters the forming cavities 4 and their filling. At this stage, the gases, as before, through the ventilation channel 6 enter the air manifold 5 and are discharged into the atmosphere through the ventilation channels 7.

The proposed solution reduces the possibility of mixing gas with the melt in the annular collector for metal and ensures its removal into the atmosphere throughout the entire filling time of the casting, which improves the quality of castings by reducing gas porosity.

Claims (1)

A sprue-ventilation system for injection molding, containing a sprue sleeve connected to an annular collector for metal, on the outer contour of which there are feeders connecting it to the forming cavities, characterized in that at a distance of not more than 10 thicknesses of the casting wall from the edge of the forming cavity ring air collector connected to the forming cavity by one continuous ventilation duct and to the atmosphere by deep air ducts of square section, total area l which is equal to or greater than the total area of the gas outlet from the forming cavity
_Holes S = P · h _{ven.kan exc,}
where S _otv - the area of exhaust gases;
P _ex - perimeter of the casting;
h _ven.kan - the depth of the ventilation ducts.