In the process of die casting, the die often meets the problems of the pouring system, the overflow system, the transverse runner, the gate and overflow tank

1. pouring system and overflow system

The pressure chamber diameter size should be based on the ratio of the pressure and the pressure chamber full of degree to selected, at the same time, the diameter of the gate set deviation should be less than the appropriate pressure chamber diameter deviation amplifying wire, thereby avoiding punch card death or wear serious problems caused by the gate set and pressure chamber wall thickness of different diameter shaft. Not too thin and the gate of. The length of the gate sleeve shall generally be less than the ejection stroke of the ram punch so that the paint is removed from the chamber.

The pressure chamber and the gate of the inner hole in the heat treatment after grinding, then along the axial direction of grinding, the surface roughness is less than or equal to Ra0.2 M.

The concave cavity of the diverter and the forming coating, the concave depth is equal to the depth of the runner, the diameter of which is matched with the inner diameter of the gate sleeve, and has a slope of 5 degrees along the direction of the demoulding. When the sprue is used, the filling capacity of the press chamber can be increased by shortening the volume of the effective length of the press chamber.

2. requirements for the transverse runner of the mold

(1) the entrance of the cold horizontal mold runner should be located at the upper part of the upper part of the pressure chamber at least 2/3, so as to avoid premature entry of the molten metal into the transverse runner under the action of gravity.

The cross-sectional area of the runner from the straight runner up to the gate should decrease gradually, to expand in cross section, there will be a negative pressure metal liquid flows through inhalation, easy parting surface gas, increase the liquid metal flow in eddy current in gas. The general outlet section is smaller than the entrance 10-30%.

The transverse runner shall have a certain length and depth. The purpose of maintaining a certain length is to stabilize the flow and guide the flow. If the depth is not enough, the metal liquid cooling fast, too deep, because of condensation is too slow, not only affects productivity and increase the amount of recycled material. The cross sectional area of the runner shall be greater than the cross sectional area of the gate so as to ensure the speed of metal liquid entering. The cross-sectional area of the main runner shall be greater than the cross sectional area of each branch.

The bottom runner should be made of rounded sides to avoid early cracks, and the two sides can make a slope of about 5 degrees. The surface roughness of the parts of the runner is less than or equal to Ra0.4 M.

3. gate

Once the metal liquid is inserted, the parting surface should not be closed immediately, and the overflow tank and the exhaust tank shall not be positively impacted. The flow direction of metal liquid into the mold as far as possible along the cast rib ribs and heat sink, from the thick wall to the thin wall filled.

When selecting the gate location, make the liquid metal flow as short as possible. When multiple gates are used, it is necessary to prevent a couple of molten metals from entering into the mold and to impact each other, resulting in defects such as eddy current, inclusion and oxidation.

The inner gate of the thin-wall parts should be suitably smaller to ensure the necessary filling speed, and the gate shall be easy to be removed without casting defects (meat).

4. overflow tank

Overflow tank is easy to remove from the casting, and try not to damage the casting body.

When overflow slot is set on overflow tank, the location of overflow port should be paid attention to, so as to avoid premature blocking of exhaust tank and make the exhaust tank not working.

No overflow port shall be opened on the same overflow channel or a wide and thick overflow port shall be opened so as to prevent the cold liquid, slag, gas and paint from flowing back into the cavity in the overflow tank, thus causing casting defects.