What is the relationship between the quality of die castings and the mould?

2019-06-05 14:35:59

Die is the main tool of die casting, so we should pay attention to make the whole structure of the die and the parts of the die reasonable, easy to manufacture, easy to use, safe and reliable when planning the die.


In order to make the die-casting die not deformed, the liquid metal in the die can move steadily, the die-casting can be cooled evenly, and the die-casting can be fully automatic without fault. In addition, suitable die materials should be selected reasonably according to the production batch and raw material condition.


Next, I will talk about how to ensure the quality of Hangfeng metal die casting.


First, the structure of the die should be reasonable, and the structure of the die parts should also be reasonable.


From the strength point of view, the die parts are planned to be all good, durable, not easy to damage in operation, not easy to deform. But if the shape of the die castings is messy and the parts of the die are messy, it will make the die processing difficult and the processing accuracy is not high. If the die parts are made into combination type, the processing is greatly simplified, and high processing accuracy can be easily obtained, thus high quality die castings can be obtained.


Resolution of Cavity Number


In deciding the number of cavity, we should consider the ability of equipment, the difficulty of die processing, the batch size of production, the accuracy requirements of castings, etc.


3. Planning of gating system


The pouring system is not only the channel for filling the die-casting mould with liquid metal, but also plays a regulating role in the transfer of melting liquid velocity and pressure, exhaust conditions and thermal stability of the die-casting mould. Therefore, the planning of casting system must analyze the structural characteristics, technical requirements, alloy types and characteristics of castings, and also consider the type and characteristics of die casting machines, so as to plan a reasonable casting system.


4. Exhaust System Planning


The die should have a sufficient overflow range of overflow slots and exhaust passages, which is very important to ensure product quality.


5. Mold Temperature


Temperature of die casting die is an important factor affecting the quality of castings. Improper die temperature not only affects the surface and inner quality of die castings, but also affects the dimensional accuracy of castings and even the deformation of castings, which makes the die casting die crack, makes the surface of castings form mesh burrs that are difficult to eradicate, and affects the appearance quality of die castings. Taking aluminium alloy as an example, the alloy temperature is poured into the casting mould at 670-710 degrees. In the long-term production practice, it is concluded that the optimum temperature of the die should be controlled at 40% of the pouring mould temperature and 230-280 degrees of the aluminium die-casting mould temperature. The temperature of the die in this range is conducive to obtaining high-quality and high-yield castings.


Dies generally do not need gas or electric heating, but choose preheating cooling device. These devices use oil as the medium to preheat and cool the mould as required.


6. Resolution on the Scale of Formed Parts


When calculating the dimension of die-casting parts, the shrinkage rate of die-casting materials should be in line with the actual situation, otherwise the products produced will be unqualified.


7.Resolution on orientation of typing surface


The orientation of parting surface will affect die processing, exhaust, product demoulding and so on. Usually, the parting surface will leave a trace on the product, which will affect the surface quality and scale accuracy of the product. Therefore, when planning the orientation of parting surface, besides taking into account the problems of product demoulding, die processing, exhaust and so on, the orientation of parting surface can be placed where the product surface quality requirements are not high or the scale accuracy is not high.


8. Mould cannot be deformed


Often because of the unreasonable structure of the die or the improper selection of the die information, the die is cracked and deformed in operation, which leads to the unqualified product. Therefore, appropriate measures must be taken to ensure the quality of the product in the planning.