die-casting molds need to have a lot of characteristics, and its various structures have requirements, so what are the specific requirements for the runner of the die-casting mold? Let’s take a look together below.
1. The cross-sectional area of the runner should be gradually reduced from the sprue to the inner gate. In order to increase the cross-section, negative pressure will appear when the molten metal flows through, and it is easy to inhale the gas on the parting surface and increase the molten metal. The flowing vortex envelops the air. Generally, the cross section at the exit is 10-30% smaller than that at the entrance.https://lasercutting-service.com
2. The entrance of the runner of cold horizontal mold should generally be located at the position above 2/3 of the inner diameter of the upper part of the pressure chamber to prevent the molten metal in the pressure chamber from entering the runner prematurely under the action of gravity and starting to solidify in advance.
3. The cross-sectional area of the runner should be greater than the cross-sectional area of the inner gate to ensure the speed of the molten metal. The cross-sectional area of the main runner should be greater than the cross-sectional area of each branch runner.https://cncmachining.jp
4. The runner should have a certain length and depth. The purpose of maintaining a certain length is to stabilize the flow and guide. If the depth is not enough, the molten metal will cool down quickly, and if the depth is too deep, the condensation will be too slow, which will affect the productivity and increase the amount of recycled material.
5. Both sides of the bottom of the runner should be rounded to avoid early cracks, and the two sides can be inclined at about 5°. The surface roughness of the runner part is less than or equal to Ra0.4μm