How To Improve The Production Quality Of Aluminum Alloy Die Castings

2018-04-08 14:15

In the casting process of aluminum alloy die casting, due to various factors, some defects may occur. Therefore, we need to learn and understand some of its relevant knowledge, know the causes of prob

In the casting process of aluminum alloy die casting, due to various factors, some defects may occur. Therefore, we need to learn and understand some of its relevant knowledge, know the causes of problems and solutions, reduce the scrap rate of aluminum die castings, and improve the quality of aluminum alloy die castings.
    Question one: How much is the roughness of aluminum alloy die castings? Aluminum alloy die castings have higher silicon content and often have small pores and crevices on the surface. In order to obtain a high decorative appearance, mechanical polishing is required. Due to the low hardness of the aluminum alloy, the mechanical polishing wheel should be soft and have a certain degree of elasticity so as to avoid deformation of the corners of the parts during mechanical polishing. The pretreatment mainly includes organic solvent degreasing, alkali etching, acid etching, and immersing in H.S.F liquid. The surface roughness of the aluminum alloy die casting molding process is generally Ra3.2~6.3; the die casting size tolerance is selected according to the national standard GBT1804-M, and the tolerance level is generally selected according to 5 levels.
    Problem 2: The deformation of aluminum alloy die castings The main stress of aluminum alloy die castings is relatively large. Placing it for a while will cause deformation due to stress release. Should be post-processing post-processing. How to solve: 1. Improve the casting structure and increase the thickness of the inner wall of the mold 2. Increase the cooling time and reduce the mold temperature 3. Position adjustment of the mold, ensure the balance of the ejector and ensure the balance 4. Clear the mold 5. Control the die casting mold temperature is reasonable, Ensure that the overall temperature of the chamber is almost balanced
    Question 3: What is the natural shrinkage rate of aluminum alloy die casting? Generally speaking, the shrinkage rate of your product should be between 0.55% and 0.65%. However, the shrinkage of aluminum alloy die casting still has a problem of body shrinkage. , It has a lot to do with the nominal size of the product's inspection reference to the position of the measured shape (the overall slender part needs special attention). The pore size shrinkage is generally between 0.3-0.4%; the dimensional shrinkage at the position is 0.6%.
    Question 4: Why is the surface of aluminum alloy die casting after shot blasting, what causes it, and how to solve it? The shot blasting of aluminum alloy die casting is to make the casting further compacted, usually about 3 kilograms force per square centimeter. If the casting itself has quality problems in the process of processing, it will produce peeling phenomenon in the shot blasting pressure in real time. This is not the same as the concept of aluminum alloy die-casting, this point should be separated. General aluminum alloy die casting surface shot after the reasons for the emergence of the following points: 1, mold or injection chamber (melting cup) is not clean; 2, injection pressure is not enough, (also need to pay attention to the dynamic model of injection (3) There is a problem with the gating system, and there is a turbulent flow of the alloy liquid into the cavity; (4) The problem of mold temperature; (5) The splash of molten metal is serious.


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