Aluminum Die Casting Mold Runner Design


Release Time:

2022-09-29

Normal die-casting production first depends on the correct position setting and shape and size of the runner system. When producing die-casting parts with large weight, great difference in wall thickness, complex shape, and strict requirements on tissue compactness, surface quality and process quality, pouring These design parameters of the channel need to be carefully designed. In any case, it is impossible to compensate for the impact of the improper setting of the runner system on the quality of the die-casting products by improving other die-casting parameters.

Normal die-casting production first depends on the correct position setting and shape and size of the runner system. When producing die-casting parts with large weight, great difference in wall thickness, complex shape, and strict requirements on tissue compactness, surface quality and process quality, pouring These design parameters of the channel need to be carefully designed. In any case, it is impossible to compensate for the impact of the improper setting of the runner system on the quality of the die-casting products by improving other die-casting parameters.

The general process of designing a mold runner system
Before the design of the die-casting mold runner system, it is necessary to fully analyze the structure of the casting and the various requirements of the customer, and determine that these requirements are basically met. The general process of designing the runner system is:
a) Select the location of the gate;
b) Consider directing the direction of metal flow;
c) Divide the number of strands of the gate;
d) Set the shape and size of the sprue;
e) Determine the cross-sectional area of the gate.

Die casting mold sprue design considerations:
(1) The position and effect of the ingate on the casting should be subject to the selected solidification sequence or feeding method. For castings that require simultaneous solidification, the ingate should be opened at the thin-walled part of the casting, and the number should be scattered on multiple sides to avoid local overheating of the sand mold near the inflow; for castings that require sequential solidification, the ingate should be opened at the thick wall. If there is a riser, so that the inflow is passed through the riser, the feeding effect of the riser can be improved; for castings with complex structures, the principle of combining sequential solidification and simultaneous solidification is often used to arrange the ingate, that is, for each supplementary In the shrinkage area, the ingates are set according to the principle of sequential solidification, while for the entire casting, multiple ingates are used to disperse the mold according to the principle of simultaneous solidification. In this way, not only can the thick and large parts of the casting be fully fed to avoid shrinkage cavities and shrinkage, but also the casting stress and deformation of the casting can be reduced; When metal is introduced, cold iron should be used to accelerate the solidification at the thick wall, and feeders should be added for shrinkage.
(2) The direction of the inner sprue should not be aimed at the fine sand core, mold wall, cold iron and core support, and if necessary, use tangential introduction. However, it should be noted that the introduction of tangents will cause the rotary motion of the metal in the mold, which is suitable for circular castings with roughness requirements on the outer surface. When the inner surface of the cylindrical casting is strictly required, the rotation of the molten metal should be avoided to prevent the slag from accumulating on the inner surface of the casting.
(3) The ingate should be as thin as possible. The benefits of thin runners are sufficient: reducing the suction area of the runner, which is beneficial to the slag blocking of the runner; reducing the cleaning workload; the runner is thinner than the wall thickness of the casting, and it is not easy to damage the casting when the runner is removed; The thin inner runner can make full use of the graphite expansion of the casting itself to obtain a compact casting. The width and length of the inner runner of ductile iron castings are 4 times its thickness.
(4) For thin-walled castings, the gating system with multiple gates can be used to realize feeding. At this time, the size of the gates should meet the requirements of the riser neck.
(5) Inner runners should not be opened in parts that require high casting quality to prevent coarse metallographic structure. For pipes that require pressure resistance and leakage prevention, the ingate is usually opened at the flange to prevent shrinkage at the pipe wall; the ingate is opened on the processing surface, which is beneficial to the appearance of the casting.
(6) In order to make the molten metal fill the mold quickly and smoothly, which is beneficial to exhaust and slag removal, the metal flow direction in each ingate should be consistent to prevent excessive turbulence caused by collision of the molten metal in the mold and disordered flow direction.
(7) Jinjing sets up the inner sprue on the parting surface to make the shape convenient.
(8) For alloy castings with large shrinkage and easy to form cracks, the setting of the inner runner should not hinder the shrinkage of the casting as much as possible.