Introduction to the method of aluminum alloy die casting to solve casting porosity
Method to solve casting porosity
First analyze the reasons for the formation of stomata, and then take corresponding measures.
(1) Choose dry and clean alloy materials.
(2) Do not overheat or degas the melt under control.
(3) Reasonably choose the die casting process parameters, especially the injection speed. The starting point for speed-regulating high-speed machining.
(4) Sequential filling helps to discharge the cavity gas. Pouring I: 1, and the runner has sufficient length. It should be 50 ram, which is conducive to the smooth flow of alloy liquid and gas discharge.
The thickness and direction of I:1 can be changed, and overflow grooves and exhaust grooves are set at the holes. The sum of the cross-sectional area of the overflow product is not less than 60% of the sum of the cross-sectional area of the gate part, otherwise the slag discharge effect will be poor.
(5) Choose good performance paint and spray volume control.
Choose the right die casting machine
Die-casting machine is the key equipment for die-casting production, and its performance objectively determines the quality of die-casting parts. The correct choice of die-casting machine is essential to ensure product quality, improve production efficiency and reduce production costs. The performance of the die casting machine depends on two aspects.
Sufficient clamping force: to prevent the flow pressure of the molten metal from reaching high peaks, and to prevent flashing and flying materials.
Sufficient injection capacity: to ensure that the stand casting process will not cause overheating or a large amount of overflow of the mold, and at the same time ensure that the machine has enough capacity to transport enough molten metal and fill the cavity as required to accelerate the speed in a short time.
Design of Die Casting Mould Runner
Because the zinc alloy must fill the cavity in a short time, the design and manufacturing of the die-casting mold and its runner system are much higher than that of the plastic mold.
The runner system guides the metal solution to fill the cavity in some way. It plays an important role in the flow direction of the metal liquid, pressure transmission, filling time, exhaust conditions and mold temperature distribution.
It is also an important factor that determines the quality of die castings.
The design principle of the die-casting mold runner system should be summarized from the gooseneck to the gate to avoid sharp corners, and the runner surface should be smooth to reduce resistance and maintain the flow rate of the liquid zinc alloy.