1. Consider the issue of wall thickness; large differences in thickness can affect filling.
2. Consider the demolding issue, which is very important in actual die-casting; problems often arise in reality, and this is much worse than injection molding demolding, so attention should be paid to the angle of draft and the calculation of demolding forces for movable and fixed molds. Generally, the draft angle is between 1 to 3 degrees; for easier demolding, the exterior draft angle is smaller than the interior draft angle, with the exterior draft at 1 degree and the interior draft at about 2 to 3 degrees.
3. In the design phase, consider the issues related to mold design; if there are multiple core pulling positions, try to place them on both sides, avoiding the lower core pull as it may cause problems over time.
4. Some die-cast components may have special appearance requirements, such as oil spraying or powder spraying; in this case, the structure should avoid important appearance locations to facilitate the setup of the sprue overflow trough.
5. Try to avoid structures that lead to complex mold designs, such as using multiple core pulls or spiral cores when not necessary.
6. For parts requiring surface processing, be careful to leave adequate processing allowances in the design; it cannot be too much, or the processing personnel will complain and expose internal air pockets; it cannot be too little either; otherwise, after rough positioning, if the black scale hasn’t been removed yet, you'll have to wait to spark the molds again. The allowance should ideally not exceed 0.8mm, as this allows the processed surface to be free of visible air pockets due to the hard layer protection.
7. Also, pay attention to material selection: whether to use ADC12 or A380, depending on specific requirements.
8. Aluminum alloys have no elasticity; to achieve snap-fit, they must be paired with plastic.
9. Generally, deep holes cannot be made! During mold opening, only small holes can be drilled, then further processing is required!
10. For thin-walled parts, they cannot be too thin, and reinforcing ribs must be applied to increase bending resistance! Since aluminum castings are processed around 800 degrees Celsius, the mold life is generally short; for motor housings, the life expectancy is only around 80K cycles before it’s done!
1. The design of die-cast parts is similar to that of plastic parts; some design conventions for plastic parts also apply to die-cast parts.
2. For aluminum alloys, the temperatures and pressures on the mold are much greater than those for plastic, thus requiring very strict correctness in design. Even with excellent mold materials, once welding occurs, the mold has almost no lifespan. Zinc alloy is similar to plastic and has a relatively good mold life.
3. There should be no recessed sharp corners to avoid mold breakage.
4. Although the precision of die-cast parts is relatively high, it is still less than that of plastic; moreover, the demolding force is greater than that of plastic, so the structure should not be too complex. If necessary, complex parts should be decomposed into two or more parts.
5. Thread holes in aluminum alloys usually only have conical pits in the mold, with post-processing adopted. A post-processing allowance of 0.3mm is generally left for areas requiring strict tolerances.
6. Die-casting of aluminum alloys is prone to air pockets, which must be considered for appearance.
It is very difficult to anodize the surface of aluminum alloy die-castings (including silicon), and they generally turn black after a longer period of time.