ZAMAK die casting, or zinc die casting is also a process similar to that of other materials. Foundries must ensure precise and efficient production to ensure high-quality outcomes. Starting from designing to surface treatment, each step needs professional work. Here is a step-by-step guide to the ZAMAK die-casting process.
Step #1 Design and Making of Die
ZAMAK die casting begins by designing the final part and mold or die. This step is the most crucial part since it mainly determines everything.
First, engineers from the foundry create the 3D model of the final part to be cast. They simulate it on various CAD software. Most of the time, they develop prototypes for testing and change the design if necessary. After making a few rapid prototypes, they finalize the casting part.
Next, they design the mold or die for the process. Similarly, they create 3D models and develop a few prototypes. During this, they consider many essential parameters.
(1) The Injection type plays a crucial role in die-casting ZAMAK alloys. Because they have a low melting point, the injection system must be hot enough to keep the metal liquid.
(2) The number of cavities is another critical parameter here. Engineers arrange these cavities for the best results.
(3) The parting system typically designs how the two halves of the die will look. The parting line is crucial for the quality of the final part and is also necessary for the finishing and trimming processes.
(4) The ejector system generally releases the part from the mold. Its design should be accurate so it doesn’t damage the final part.
(5) Engineers also carefully arrange the cooling system for the whole process. An appropriate cooling system prevents many casting defects.
(6) Finally, choosing a suitable material for the mold is also important here. High-quality tool steels are usually used for this job. Popular tool steels are H13, SKD61, 8407, and 8418.
Step #2 Preparing ZAMAK alloy
Once the mold is ready, engineers install it with the machine. Next, they prepare the ZAMAK alloy. Various techniques are used to refine the ZAMAK alloy. Some popular methods are thermal refining, chemical reaction, electrolytic refining, and zone refining.
The method melts the ZAMAK alloy in a furnace to give it a liquid form. A proper temperature is controlled in this case, ensuring the alloy melts evenly. Engineers usually remove the impurities during this step.
After refining, the process keeps the molten metal in the injection chamber. Once again, the temperature is controlled correctly here. In addition, proper sealing is also necessary. This controlled environment is crucial for preventing contaminations.
Step #3 Injecting the Molten ZAMAK into the Die
Injecting the molten ZAMAK alloy into the die is critical in the die-casting process. Engineers usually prepare and keep the molten metal in the injection chamber in the previous step. Indeed, this chamber is well-sealed and controlled.
The injection device uses a plunger or piston to push the molten metal into the die. In this case, a certain pressure is necessary. Note that, based on this pressure rating, the type of die-casting may vary. However, the pressure forces the molten metal to reach every mold corner, filling the cavity.
FYI: Proper injection technique is crucial for high-quality castings. In addition, it also ensures a smooth and even surface finish. Therefore, when designing a mold, the injection channel must be well-planned.
Step #4 Cooling and Solidifying the Die Casting ZAMAK Parts
Once the molten ZAMAK alloys fill the die, cooling begins immediately. Since the mold is made of high-quality tool steel, it quickly draws heat away from the molten metal. However, the mold has a rapid cooling system helps cool and solidify the molten ZAMAK parts.
Different types of cooling systems can be used in various situations. Water and air cooling is the most popular in this case. These systems offer consistent cooling rates. You know, this even cooling is extremely necessary for high-quality ZAMAK parts.
FYI: A proper cooling system is always necessary for consistent solidification. It also helps in preventing many casting defects.
Step #5 Ejecting the Solidified ZAMAK Die-Casting Part
Once the ZAMAK alloy has solidified, it must be removed from the die. This step is typically called ejection. FYI: An appropriate ejection ensures the part’s quality and integrity.
An ejector pin typically does this work. These pins help push the part out of the mold. (1) The die opens. (2) It separates into two halves. (3) the ejector pin activates. (4) They push against the casting. It gently forces it out of the die.
The operator does it very carefully. It is evident that too much force can damage the part. Therefore, properly aligning the ejector pin avoids marks or dents on the final part.
Step #6 Finishing & Trimming
After ejection, the part usually comes with an extra part that needs trimming. These excess parts are also called flashes. These flashes generally hamper the performance of the die-cast ZAMAK parts.
Foundries use different trimming machines based on different situations. Grinding or polishing machines help a lot here. Some small-scale foundries may do it manually. However, various surface treatments are implemented on ZAMAK die-casting parts for further finishing.
Step #7 Surface Treatment
As mentioned in the previous step, you can give a surface a premium look using various methods. Different surface treatment methods are used for varying application needs.
Surface treatment is the final step of the ZAMAK die-casting method. It mainly improves the aesthetics of the metal parts.
Zinc plating is one of the most common methods here. This process typically involves coating ZAMAK parts with another metal. Black Nickel electroplating, chrome, and zinc are popular plating materials.
Another widely used method is painting. Painting generally adds color and extra protection. Although painting is not as effective as other methods, it is cheap and easy. You can do it either by spray paint or powder coating. Note that powder coating is generally more durable and resistant to chipping.
Anodizing is another effective technique, though it is less famous than plating. It increases surface hardness and corrosion resistance, for example some zamak 3 or zamak 5 die casting that use gold anodizing finish for some funiture components.
There are other surface methods as well. However, each method described above has its unique advantages and limitations. The choice mainly depends on your project needs and budget.
