Investment casting vs. die casting are comparable in several ways and it can be challenging to decide which method will work best for a product.
Investment casting creates metal parts with exceptional surface finishes, usually in the 125 RMS range, but requires a new mold to be created for each cycle. Die casting has the most significant economic benefit for non-ferrous parts and large production volumes.
Perhaps you are working on a new part fabrication and do not want to commit to the tooling costs of die casting.
Or maybe you are increasing production and are ready for a cost-effective manufacturing option.
In this article, we do a deep dive comparing investment casting and die casting so you can better understand your production options.
Investment casting is a metalworking process that produces precise parts and components with excellent finishes while also limiting material waste. It is also called precision and lost wax casting. This name comes from the initial steps of the process where a wax pattern is created, then dipped into a ceramic slurry until it hardens. The wax is then melted, leaving a sturdy mold that is used to cast metal parts.
To understand its value in manufacturing, it is important to know the entire casting process and how investment casting differs from die casting.
The entire process starts all over again to cast additional parts.
Die casting is different from investment casting in that it uses a permanent mold or die that does not need to be remade for each casting cycle. This method is considered the most efficient method for producing precise non-ferrous metal parts.
There are two die casting methods called the hot chamber and cold chamber method, but they differ in machinery and metal. Otherwise, the entire casting process is mostly the same.
First, a steel die that contains the pattern for a part is created. These molds are created in two sections, sometimes more, that are mounted on a machine and tightly held together.
Molten metal is then injected into the die where it can cool. The die halves are pulled apart, and the casting is ejected from the mold. The process then repeats itself, which allows manufacturers to create many parts and components in rapid succession.
The casting dies can be simple or have cores and moveable sides, depending on the finished part’s complexity. Dies can withstand up to 150,000 to over 1,000,000 cycles before needing replacement or repairs.
Hot Chamber Method
As we mentioned earlier, die casting follows the same basic steps. Hot chamber die casting is used for metal alloys with low melting points.
In hot chamber machines, metal is heated in a furnace that is attached to the machine and fed into the die via a gooseneck. This is a fast process with cycle times varying from under a second for smaller parts that weigh less than an ounce to thirty seconds for a casting that weighs several pounds.
Cold Chamber Method
The primary difference between cold chamber and hot chamber casting is the location of the furnace. Metals with higher melting points require a strong furnace and more energy to reach a molten state. Those temperatures would erode hot chamber machinery, specifically, the injection components.
Cold chamber machines are constructed with a separate chamber where molten metals are poured. Metal is also heated in a furnace separate from the machinery and either poured into the chamber by hand or automatic ladle. This makes the process less efficient than it’s hot chamber counterpart.
What types of parts can be investment cast?
This is a common question, and its applications are nearly limitless, with many industries utilizing the process.
Which industries benefit from die-cast parts?
As we mentioned before, die casting is the most popular technique used to mass-produce commercial, consumer, and industrial products such as vehicles, construction materials, gears, and heavy machinery.
Its design flexibility and metal options combined with its cost efficiency make it a favorable choice worldwide. With this method, companies and designers can create parts and components specific to their needs with little production time and great accuracy.
When selecting which method is best suited for your unique production, you will want to consider the following variables:
You may also want to consider exploring investment casting vs. sand casting. Like all metalworking processes, each offers benefits and drawbacks but will largely depend on factors like cost, application, and material.
During sand casting, molten metal is poured into a sand mold. Metals such as magnesium, brass, steel, iron, and other non-ferrous metals can be cast.
Molds are created by mixing sand and clay with a binder and then forming a pattern around the final part. The mold is filled with metal, allowed to cool, and the final part is removed. Sand is then reused to create another mold, and the process begins all over again.
With sand casting, several of the same parts can be produced simultaneously, or a range of parts that share a mold can be cast.
Due to the complexity of the mold and preparation required, investment casting tends to be more expensive than sand casting.
Investment casting uses liquid slurry to form the molds, so cast parts can have almost any shape, giving engineers extraordinary freedom in their designs to add intricate features and complex shapes. Sand-cast parts usually must be tapered (with draft angles) or shaped so that they come out of the compacted sand easily and with little friction. It’s also a challenge to sand-cast parts with internal voids or cavities. It requires cores properly shaped and inserted in the mold to form the part’s interior. Several cores may be needed, and it can be time-consuming to form and secure them within each mold.
Sand casting usually cannot produce small and intricate parts that are possible with investment casting. Additionally, investment casting can create hundreds of small parts at once or even a single 1000 pound engine component.
Because of the complexity and number of steps in creating an investment cast most, it can be more expensive than sand casting.
Sand casting offers greater design flexibility because it is relatively simple to change a sand mold. For investment casting, technicians may need to modify or replace a metal pattern or create new wax versions, which is a complicated process.
Final sand cast parts have demarcation lines that require additional processes to remove. Additionally, the rough texture of the sand leaves a rough finish on cast parts. Investment castings are valued for their excellent finish, which requires little to no extra processing.
Choosing the best casting process for your part is not always clear, and there are tradeoffs with each method. Let our team help you understand your options and find the best manufacturing partner to deliver high-quality parts at competitive prices.
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