Aluminum Alloy casting requirements:
The density of the foam model should be small and precision casting. Under the premise of ensuring the quality of foam surface quality alloy castings and retaining the strength of the casting model, the foam should be made as light as possible to reduce the amount of gas generated during pouring.
The foam model must be dried before coating, and each batch of foam model should currently check the weight change during the process of drying the casting parts, and make a change curve of the baking weight, only when the weight no longer changes. coating.
The gating system, especially the sprue and runner, should not be coated so that the gas generated during pouring can be quickly charged.
A baffle is placed on the casting face of the sprue cup, which can block the molten steel returned from the precision casting so that it cannot splash out and endanger the on-site operation workers.
It is best not to paint the cast parts of the paint at one time. Once it is finished, the paint will thicken the coat, and the paint is easy to crack. It should be two to three layers. The overall thickness of the coat should be controlled at about 1mm. The principle of controlling the coating thickness is that the coating should be as thin as possible on the premise that the casting does not stick to the sand so that the gas can be discharged through the coating as soon as possible.
After each layer of paint must be dried, it can be used for the next round of brushing or sculpting. If the coating is not dried, molten steel will produce a lot of gas when pouring, causing back spray, and the other coating Did not dry out, poor permeability of paint, gas can’t be discharged in time, easy to make the castings have pores, slag hole. Re-injection is a common phenomenon in lost foam casting. When the back-injection is severe, it may endanger the caster's personal safety castings and must be valued.