Cooling system design of four components in the HPDC gating system
The use of die-casting molds in high-temperature and high-pressure is extremely harsh and can easily affect the surface quality of the castings and the producing life of the molds. Therefore, the correct cooling system design has a great impact on production efficiency, casting quality, and mold life.
It is understood that the cooling water opening method means that the cooling water should be turned off before the mold is produced, and then preheated, and after the preheating reaches a certain temperature, the temperature of several molds in the die-casting is integrated and the cooling is started. The cooling water is gradually separated by several produce cycles. The valve is opened to the specified opening degree. In the production, the cooling intensity of the cooling system should be adjusted separately by adjusting the opening degree of the valve core, and the thermal balance of the mold can be achieved by spraying.
Therefore, the cooling system of the four components of the gating system are introduced as follows:
The use of the shot sleeve is beneficial to ensure the coaxiality of the punch movement, avoiding the influence of different axes caused by manufacturing errors of the shot sleeve and the sprue bushing, thereby reducing the phenomenon of card punching and effectively improving the punching Head life.
2. Pluger connecting rod and pluger
The cooling method of pluger connecting rods and pluger (in order to reduce costs, the pluger connecting rods are repeatedly used, and some are added with the pluger connecting bushing), that is, the cooling water enters and exits from the connection between the injection connecting rod and the die casting machine. To achieve a good use effect, generally adopt the forced cooling method of inserted copper tube (iron tube is easy to rust), to ensure that the cooling water with low temperature reaches the injection punch first, with heat, to achieve the cooling effect.
The sprue bushing is the first place to contact the aluminum liquid in the die casting mold, and also the place with the highest temperature. In the production, it is very easy to cause flash and strain due to the improper fit clearance between the pluger and the sprue bushing, which makes a large amount of punch consumption a big problem for many die casting manufacturers. Therefore, whether the mold forming part needs cooling water or not, the sprue bushing should be set in the fitting section Cooling water.
4. Mold forming part
(1) Jet cooling: It is suitable for deep cavity molds and cores of separate parts, and only a few deep cavities or separate cores are drawn at the molding part, which is common in die castings. Wrapped aluminum liquid can easily cause the mold to overheat, causing sticky mold strain, thermal cracks, etc. At this time, the deep cavity mold through-point cooling water is required for forced (copper pipe) cooling to ensure that the cooling water is cooled in and out.
(2) Water lines: It is suitable for the structure where the molding part is generally not deep, and it is not necessary to cool a certain part separately, only the entire molding part needs to continuously take away the mold heat. According to the structural characteristics of the mold forming part, in some cases, even if cooling water is not required in other parts, the lower and lower parts of the moving and static mold kernels are the first to contact the aluminum liquid, which is usually an overheated place and needs to be cooled.
（3）Mixed use of water line and jet cooling: many moving and lining cores and line forming parts are generally not deep but partially too deep. At this time, water lines and jet coolings are required to be used together, which is relatively common. To facilitate the control of water line and jet cooling, the cooling water can be set separately according to the structure, or the secondary cooling water can be set together.