History of Investment Casting

There have been comparable manufacturing techniques for over 5,000 years. Pure beeswax patterns were used to cast softer metals like copper and gold. Archaeologists have uncovered interesting artefacts, jewellery, and idols from those eras.

As people became more adept at working with metals, they experimented with different techniques for casting metal. It gained popularity in the late 19th century when dental crowns were made with it.

But World War II was the event that made this approach widely known. A casting technique was necessary for military use to reliably, precisely, and robustly produce parts. As a result, work over those years improved the method currently referred to as investment casting.

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Finding out what is meant by investment casting is the aim. What precisely is the “investment” casting cost, then? In the past, the word “invested” meant to be “clothed” or “surrounded.”  An investment casting shell is produced around a wax design using ceramic, plaster, or plastic. To manufacture the casting, metal is poured into the body after the wax design is melted and removed in a furnace.

The Importance of Investment Casting in Today’s Industries

It can create precise, complex, high-quality components; investment casting is essential to many modern businesses. Here are a few main justifications for the significance of investment casting:

  • Complex geometries and detailed designs:Using investment casting, items with intricate detailing and complex shapes that would be challenging or impossible to do with conventional casting techniques can be created. This is especially helpful for sectors like aerospace and medicine, where intricate geometries are frequently needed for components.
  • Great precision and accuracy:Investment casting can create components with extremely tight tolerances and great dimensional consistency and accuracy. Time and resources are saved because there is no longer a need for additional machining or finishing.
  • Material versatility:Different metals and alloys, such as steel, stainless steel, aluminium, brass, bronze, and other superalloys, can be employed with investment casting. Because of this, it can be used in various industries, each with unique material needs.
  • Outstanding surface finish:Investment cast components typically have a superior surface finish. This lessens the need for extra surface treatment or finishing procedures while enhancing the component’s visual appeal.
  • Cost-effectiveness for small batch production:Investment casting can be expensive to set up initially but more affordable for small to medium production volumes, particularly when making complicated components.
  • Versatility in size and weight:Investment casting provides excellent versatility in the size and weight of the components that may be produced. Parts ranging in size from a few grammes to several hundred kilogrammes can be made.

What is die casting?

While die casting parts involves higher initial costs compared to some casting methods, it tends to result in lower per-unit costs for high-volume production. Other advantages of die casting include smooth surface finishes, corrosion resistance, the ability to produce complex shapes and durable products, and a reduced need for some secondary machining processes. The two types of die casting machines are cold chamber die casting and hot chamber die casting machines.

The die casting process

The die casting process involves multiple steps. Here’s a step-by-step look at the die casting process:
    1. A steel mold must be made into two (or more) sections to allow for the removal of castings.
    2. This mold can produce thousands of castings quickly in succession.
    3. After being securely mounted into the machine, the sections are arranged with one stationary section (fixed die half). At the same time, the other section can move (injector die half).
    4. These two halves are clamped together by the machine – thus, beginning the casting cycle.
    5. The die cavity is injected with a molten metal, which then rapidly solidifies.
    6. Once the die halves are pulled apart, the casting is ejected.
Die casting dies can be designed to be simple or complex, can possess moveable slides, cores, or other sections, depending on the casting’s complexity.

Is die casting right for your product?

Die casting may not be the perfect solution for every project. One of the disadvantages of die casting is that it has a high mold cost. At The Federal Group, we offer a wide range of metal casting services, including:
  • Investment casting
  • Rapid prototype casting
  • Sand casting
  • Lost foam casting
  • Lost wax casting
  • Centrifugal casting
  • Permanent mold casting
Some projects may also benefit from metal stamping or forging instead of die casting. The choice depends on a variety of factors, including the size, mechanical properties, and geometry of the part.

What is the difference between the hot chamber and cold chamber die casting process?

We employ two types of die casting machines. Depending on the material and timeframe, we may use a hot chamber machine or a cold chamber machine. Both the hot chamber process and cold chamber process each have their own unique characteristics.

Hot chamber die casting process

Hot chamber die casting relies on a piston to force the molten metal into the dies. The hot chamber machine has a built-in furnace to heat the metal. The hydraulic-powered piston then forces the metal into the die at a fast pace with a typical cycle lasting just about 15 minutes.

Hot chamber die casting provides an efficient solution for tin, zinc, and alloys with lower melting points.

Cold chamber die casting process

Cold chamber die casting include an extra step in the process. Instead of a built-in furnace, these cold chamber machines require a separate furnace to melt the metal.

The molten metal is transferred to the cold chamber machine using an injection cylinder. The cylinder extrudes the metal into the die using a piston. The additional step of transferring the molten metal increases the production cycle of cold chamber die casting.

The main advantage of cold chamber die casting is the ability to work with a wider range of metals. Metals with a high melting point require the use of a separate furnace, which is not an option with hot chamber systems.

Cold chamber die casting is best suited for working with materials like brass, steel, copper, nickel, iron, and occasionally aluminum.

What is the difference between sand casting and die casting?

While die casting relies on high pressure to force the liquid metal into the mold, sand casting involves pouring molten metal into a sand mold.

The sand casting process includes a mixture of sand and clay pressed into boxes called flasks. The model part is placed in the mixture, creating a mold. The molten metal is poured into the mold to create the desired shape.

When the metal cools, the sand is blasted away. Our sand casting process produces high-quality parts with minimal porosity and defects compared to die casting. Sand castings are also suitable for a wider range of materials.

While we offer alloy die casting services, die castings do not work with all materials. Sand castings can be made from various ferrous metals and non-ferrous alloys. However, sand casting is a more exhaustive process.

If you have a short timetable for your product development cycle, die casting is the preferred manufacturing process. Our die casting services include fast turnaround for most projects.

What is the difference between investment casting and die casting?

Investment casting is another casting process offered at The Federal Group. With our investment casting services, we create wax patterns from a master die. The wax patterns are coated in a ceramic material that eventually hardens. The wax is then melted, leaving an empty ceramic mold. This process allows for very intricate designs and greater precision compared to die casting parts. While investment casting requires less tooling, the price per unit is often higher. It is also a more time-consuming process. In the end, die casting is the preferred choice for a wide range of applications. It remains one of the most efficient casting processes, especially for high-volume production runs. Depending on your specific project, little to no machining is required.

What is the vacuum die casting process?

Vacuum die casting is a unique version of the die casting process. In conventional die casting, molten metal is injected into a mold under high pressure.

In vacuum die casting, a vacuum is applied to the die cavity before or during the injection of molten metal. This process offers several advantages, primarily in reducing the presence of gas porosity in the final die cast parts.

Does die cast metal rust?

Ferrous metals such as carbon steel, alloy steel, and stainless steel all can rust because they contain iron. It’s possible to die cast these metals, but due to their propensity to rust, it’s quite uncommon.

Non-ferrous metals, such as aluminum and copper, contain only trace amounts of iron, at most. Therefore, they don’t rust. But they can corrode, a factor that’s primarily dependent on the given working environment.

High-pressure die casting & gravity casting

At The Federal Group, we also offer high-pressure die casting and gravity casting based on the requirements of the project or the properties of the components.

Gravity casting is typically used for heavy products and high-volume production runs. It relies on gravity to allow the melted metal to naturally flow into the mold cavity. Compared to sand casting, this process is better suited for projects that require thin walls or a smooth surface.

Along with gravity casting machines, we have several types of high-pressure die casting machines including 600-ton, 800-ton, and 1200-ton machines. These machines allow for fast turnaround, thanks to shorter casting cycles.

Die casting machines

We have a versatile line-up of high-pressure die casting equipment:
  • 600 Ton die casting machine
  • 800 Ton die casting machine
  • 1200 Ton die casting machine
These machines have excellent process repeatability and are capable of very quickly making parts with thin walls. Ideal for automation, our high pressure machines have short casting cycles that will optimize your production capabilities and will produce parts that are beyond your expectations. The requirements of your components will dictate which die casting machine is the best solution for you.

Die casting materials

Die casting usually uses non-ferrous alloy material because it has a high dimensional stability. The four most commonly used alloys for die casting are:
  1. Aluminum
  2. Magnesium alloys
  3. Zinc
  4. Copper
The choice of die castings materials is influenced by several factors such as density, melting point, strength, resistance to corrosion, and cost. The material influences the type of machine used too.

Which metals work best for die casting?

Of course, like with other metal fabrication processes, die cast parts will only be as good as the molten metal being used in their production. The source metals will impact the overall quality, durability, and aesthetic appearance of the finished product. As such, this blog will explore the various metals involved in the die casting process.

Aluminum casting

Aluminum is one of the most popular metals used in die casting. Aluminum is a very lightweight metal, so it’s great for creating lightweight parts without sacrificing strength. Aluminum parts can also withstand higher operating temperatures and have more finishing options.

Despite being pricier options, aluminum and aluminum-zinc alloys are definitely worth the cost in industrial applications. They are incredibly corrosion-resistant materials that contribute to an extended lifespan and improved safety. Furthermore, the strength, hardness, and weight ratios are unparalleled.

Another clear advantage of molten aluminum is that – plainly – it’s easy to cast. Its electrical and thermal conductivity properties are optimal. These characteristics make aluminum an excellent option in the production of components for computing, energy management, and other tech fields.

Because of these many benefits, aluminum casting is very popular in the production of things like industrial components, automobile parts, tech products, aerospace products, and much more.

Image Above: Aluminum die cast housing manufactured by The Federal Group, USA.

Zinc die casting

In addition to aluminum, zinc is another very popular metal used in die casting. Zinc is typically used for casting products for the automotive and medical supply industries.

When items are being customized for aesthetic purposes, zinc castings tend to be the best choice. The material can be plated or painted depending on the need. It also offers a smooth surface to work on. Zinc allows fabricators to produce components capable of custom aesthetic quality as well as strict and narrow tolerances for shapes morphology

Zinc has a low melting point, which means it requires less energy for production. The low melting point also helps to extend the mold life which is another pivotal factor in zinc’s value as a molten metal.

Finally, zinc’s corrosion resistance levels are impressive, and it has heightened thermal conductivity. Thus, this material is durable, hard, and stable.

Magnesium die casting

Magnesium is another metal that is commonly used in die casting. Magnesium is the easiest metal to machine, it offers an excellent strength-to-weight ratio, and it is the lightest alloy commonly die cast.

Magnesium alloys have a variety of unique characteristics like excellent fluidity, less susceptibility to hydrogen porosity, and better castability over other cast metals such as aluminum and copper. Magnesium also offers EMI and RFI shielding properties which makes it perfect for connectors and electrical housings.

Magnesium is used in a wide range of applications. Since it’s Aside from connectors and electrical housings, magnesium is also often used to produce medical and laboratory equipment because it provides protection against interfering signals.

Magnesium is also 75% lighter than steel with no significant loss of strength. This makes it a much better material for thin-walled, complex net shape castings. It also offers greater dimensional stability.

Magnesium castings can meet tight tolerances that would be difficult or impossible to achieve with steel.

Die Casting Dies

Die casting dies, also known as molds or tooling, are critical components in the die casting process. These dies are typically made using several key steps and consist of various components. Here’s an overview of how die casting dies are made and their main components:

Die Block Preparation

A large, solid block of the chosen die material is prepared, and it is typically milled, drilled, and machined to create the basic die shape.

Cavity and Core Inserts

The die is divided into two die halves or components: the die cavity and the core. The die cavity is the negative shape of the part to be cast, while the core is the positive shape. These components are precisely machined and are often made separately to allow for easy maintenance and replacement.

Ejector Die System

The ejector die system is designed to remove the cast part from the die once it has solidified. It typically includes ejector pins, ejector plates, and a mechanism to push the part out of the die.

The Federal Group’s die casting capabilities

The Federal Group utilizes both traditional and cutting-edge die casting processes to produce parts that are reliable, high strength, and accurate for use across a multitude of industries and components. We use both gravity casting and high pressure casting to manufacture parts based on product requirements.

Before a part can be formed the metal is melted in either of our two high-volume furnaces: Our 10,000 lb and 20,000 lb furnaces are precisely controlled to heat a given metal to ideal working temperatures.

Historically, gravity casting was the first form of casting and is still used today for heavier products or products that are to be made in medium to high volumes. It utilizes gravity to allow the molten metal to flow throughout the mold cavity.

This process is capable of creating thinner walls with a smoother surface than is possible with sand casting. Gravity casting is highly repeatable and steel pins and inserts can even be cast into a part.

Decades of die casting experience

Why choose The Federal Group for your custom metal fabrication and custom die casting needs? For the past forty years, we have produced high-quality custom metal products and developed a large network of partners around the world to source the best materials. We deliver fast solutions at competitive prices and pride ourselves on our:
  • Quality management processes
  • Collaboration and innovation
  • Decades of manufacturing expertise
  • Solutions for a variety of industries
Our quality management system ensures that your parts meet the standards of your industry. We offer a production part approval process (PPAP) and pre-production quality planning. Our production techniques also involve in-process controls. Along with these steps, we collaborate with you from the beginning to help eliminate issues during the design phase. Our engineers work with you to create more efficient, high strength, cast parts and components. These solutions are available for businesses in every industry. We regularly work with clients in the automotive, aerospace, agricultural, construction, and telecommunications industries.

Start a die casting project today

Whether your project requires complex shapes, multiple components, high dimensional accuracy, or corrosion resistance, we have the best casting method for you. The Federal Group USA has been a leader in the die casting industry for more than 40 years. To learn more about our custom die casting processes or to receive a quote for your project, contact us today.

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