If you have ever seen parts or equipment manufactured on a large scale, you have likely wondered how all those parts are made, and how much time it takes. The standard technology in place is die-casting, a process in which liquid metal is poured into a mold to create the desired part. While this is very helpful and cost-effective, new technology is on the rise to make even more progress in this area of metallurgy: Integrated Die Casting.
What is Integrated Die Casting?
Integrated Die Casting (IDC) is a process in which liquid metal is injected into a mold to create a specific shape, but, once the metal has cooled, it is formed into a whole component, rather than needing to be welded or further manufactured (as is the case with traditional die casting).
This new process is just beginning to be introduced commercially, and it has many different benefits. Because this technology is so new, we will examine the development, process (including materials used), benefits, and finally, the application process in the industry of this new process.
The Development of Integrated Die Casting
In a way, tracing the development of IDC means following in the footsteps of Die Casting itself. The process of die casting dates as far back as the 1800s, and was a vital technology during the era of the printing press. Halfway through the 18th century, the manually operated die casting machine and the linotype machine were created to further speed up the process of publishing using metal letters. But it didn’t stop there.
New Processes and New Materials
Traditionally, both tin and lead were the standard materials used in the die casting process, but at the turn of the 19th century, both aluminum and zinc became new materials to be used (and preferred) in the die casting industry. This was mainly due to two factors. One, these metals were safer than lead and tin for those handling them. Two, both of these materials were stronger than their predecessors, allowing for stronger creations and new applications.
The Present Day
By the 1930s, most of the metals and alloys that we use in the die casting process were introduced, such as copper and magnesium. Moreover, the actual casting process initially started with only low-pressure systems, but with the increase of new technology (and the use of new alloys) high pressure injection systems became the new norm.
Common Materials Used in IDC
As listed above, many different metals have been used for the process of die casting, but nowadays the most commonly used metals are aluminum, zinc, and magnesium, but both copper and brass are used as well. Let’s review the various properties of these metals and how they are used in the industry.
Because of its low mass, aluminum is a great material to work with given that it does not decrease the strength of the part being created, at the expense of more weight being added. Generally speaking, aluminum parts can withstand higher temperatures, and thus have slightly more finishing options than other materials. Moreover, aluminum is quite an easy metal to cast given its properties, and it is a great option if you are looking for a metal that is corrosion resistant–especially when combined with zinc as an alloy. While aluminum does have many benefits, it is important to remember that aluminum and other aluminum-based alloys have a bit higher price point than other products.
Because of the merits mentioned above, aluminum is commonly used in the field of technology. This is because it is highly conducive materially, for both electrical and thermal uses.
One of the greatest benefits of zinc is that it has a low melting point (787.15 F) which means it takes much less energy to melt compared to other metals. Using less energy to prepare the metal for casting means that you not only have fewer overhead costs, but you also are using a metal that has a longer mold life than other metals. Furthermore, zinc is a great metal to customize. It is easily painted or plated, and offers a highly smooth surface to work on, which allows for more options when finishing your product. As a bonus, zinc boasts of high anti-corrosion properties and high thermal conductivity.
In terms of usage, due to its high mold life from its low melting point, zinc is a favorite when it comes to casting various medical supplies such as parts for blood pressure monitors.
While not as common as the other metals listed, both copper and brass are valuable materials to use for the die casting process. Copper offers many benefits as a die-cast metal, such as high hardness levels, good corrosion resistance, strong dimensional stability, and very high conductivity. On the other hand, brass also has very similar properties to copper, but with the added benefit of being both easily polished or plated, as well as having a high-temperature resistance. Moreover, brass is easily mixed with other metals or alloys during the casting process, to make the final product meet as many specifications as possible.
As copper is highly conductive, its major application of it in the industry is the creation of powerlines and household wiring. Moreover, copper is a great material to use in the making of heat sinks for computers and various battery modules.
In terms of the application of brass products, the most common uses are the creation of fittings, water pump parts or components, and various fitting parts. As somewhat of an aside, because brass can easily be polished, the parts created can have much more aesthetic value than other metals, adding more value to the final product.
As a metal used in die casting, magnesium offers many benefits. Firstly, it is the lightest metal used in the industry, making it the metal with the best strength to weight ratio. Secondly, many magnesium alloys have excellent fluidity, and greater casting ability when applied over other metals such as copper and aluminum. Finally, because magnesium has a high tolerance for hydrogen porosity (a defect that can happen during the casting process in which voids are created in the cast due to high levels of hydrogen gas being present) it is a great material to use to ensure that the various die pieces you create are sturdy for an extended period.
Given its ability to shield against Radio Frequency Interference (RFI) and Electromagnetic Interference (EMI), magnesium is a great choice when it comes to choosing a metal for medical and lab equipment, as it is unaffected by various types of interference.
The Integrated Die Casting Process
Before examining each step of the die casting process, it is important to clarify two different types of casting: hot chamber and cold chamber. With hot chamber casting, after the metal or alloy is sufficiently melted, it is immediately injected into the die (the mold used to create the desired part) using a hydraulic system. On the other hand, cold chamber casting involves scooping the molten material into a cold chamber before injection. While there are some differences between the two procedures, they involve the same injection process but at different temperatures.
With a basic understanding of the major industrial casting types defined, let’s take a look at the overall casting process. Keep in mind that these steps may vary depending on what method of casting you decide to use.
Step 1: Preparing the Die (mold)
In preparing to create the desired product, the die or mold will be lubricated using a type of release spray. This allows for the part to be released easily instead of possibly sticking in the die. The mold can have one or more cavities, and this depends on the character of the final products. When the cost of one injection is fixed, the more cavities there are, the lower the average costs of final products will be.
Step 2: Clamping
At this stage, the two halves of the die are compressed together by a machine that determines the necessary amount of force to be used. These two halves are fixed on the die casting machine during this process.
Step 3: Injection & Cooling
The molten metal is injected into the die using a hydraulic pump, at a specified pressure, as to not damage the product. After the die has been filled, it is then cooled to a certain temperature to prepare for ejection. Once the product is sufficiently cooled, the solidified metal will have a shape similar (if not identical) to the die you used.
Step 4: Ejection of the Product
The die is unclamped, and the two halves are separated. Then an ejection mechanism pushes out the mold carefully. This process must be monitored heavily to ensure the product is not damaged.
Step 5: Trimming & Finishing
In the final stage, excess metal from the die is trimmed off and the final product is trimmed and finished to ensure very high quality. After special surface treatment such as powder coating， plastic coating, oxidation, polishing, plating, and so on, now your desired part is ready for use!
At this point, you may be wondering, “how does Integrated Die Casting differ from the standard casting process?” This is a fair question. To put it simply, the IDC process involves creating a large, singular piece where the standard process would have created multiple pieces that would have had to be welded or manufactured together. Let’s now turn to the various benefits of this process.
What are the Benefits?
One of the major benefits of using IDC is the mitigation of manufacturing costs by reducing the number of separate parts needed to be made, as well as the various steps to attach them to form the desired product.
A second point is the reduction of C02 emissions and the increase of energy productivity by at least 50% as noted in a study from the U.S. Department of Energy. This is mostly because IDC can replace the traditional multi-piece method by creating a singular, strong product that does not need to be welded or stamped.
As a case in point, Tesla adopted this technology for the manufacturing of the rear frame of their Model Y vehicle. Originally it was stamped and welded using 70 different parts, which took around one to two hours to complete. Using the IDC method, this process now only takes a total of 45 minutes, and 300 fewer robots to complete the procedure. Talk about a reduction of costs!
Where is IDC Being Used?
So far, the major application of Integrated Die Casting technology has been in the automotive industry. Major car manufacturers such as Tesla and NIO have used this process to create more lightweight and stronger components for their vehicles, most notably with their subframes, and other components. The use of this technology in the automotive industry is very different from the traditional stamping and welding procedure and has realized many different benefits, such as the ones listed above, with many more to come in the future.
Integrated Die Casting Technology is a procedure that can revolutionize the auto industry, as well as many other sectors. It is worth keeping an eye on.