Investment Casting Advantages and Disadvantages

When it comes to manufacturing, every part should meet its precise specs for the final item. Many processes can be used to make unique components to a product. Investment casting is one such unique technique and one that stands out due to several reasons.

Investment casting is an essential metal casting process with specific process parameters than other metal casting processes, including expandable mold casting and sand casting. This article explains the general investment casting process, focusing on the advantages and disadvantages of investment casting. Additionally, the article will explain why investment casting is used in industries today.

What is investment casting?

In a nutshell, investment casting is a complex precision casting technique that uses replication of wax patterns to produce near-net-shape and more detailed products. It is also known as lost wax casting.

Also known as precision casting or lost wax casting, investment casting processes produce high accuracies and dimensions. The process is used in many industrial processes. In the investment casting process, molten metal is poured into the mold, found after the solidification process. Additionally, a metal like steel is used to make patterns used to develop objects with clear surface finish and accurate dimensions.

The final casting process requires a master mold obtained from different acids, such as silicates. After getting the final casting product, the master mold is heated until it melts before cooling down. The cooled mold offers the final product.

Applications

What makes the investment casting process such a popular technique? The process is excellent for making prototypes and products. Investment casting technique is widely applied in various industries, such as the automotive and manufacturing sectors.

Different applications of the investment casting process depend on the metal used. In most cases, the best results are achieved if the company uses refractory metals with high melting points. Investment casting is used in making jewelry, computer parts, turbine blades, and aerospace components.

The Investment Casting Process

The investment casting process applies superfluous patterns designed from investment wax. The entire process can be described as follows:

  • Wax patterns are primarily designed through injection molding technology. This technology involves injecting wax into a prefabricated die with similar cavity geometry as the desired cast item.
  • After making the wax patterns, they are attached to a gating system. The gating system is a set of channels used to direct the molten metal to the mold cavity.
  • The next phase is called shell building. In this stage, the wax assembly is deep into the refractory ceramic slurry to harden the mixture then dry it. The process is done repeatedly to form a solid ceramic shell that is between 6mm and 9mm thick.
  • The dewax stage follows the shell-building phase. During the dewax phase, the assembly is heated in an autoclave. The wax is mainly melted out in this stage. The process is followed by burning the remaining wax in a furnace.
  • The mold goes through preheating to 1000°C. At this stage, the mold would be ready to be filled with molten metal.
  • The casting phase is a traditional process that involves pouring the molten metal into a shell. The gating system is used to direct the metal into the shell.
  • After solidification, the shell is broken. The casting is then cut away from the sprue and gates.
  • The finishing stage is completed through sandblasting and machining.

Advantages and Disadvantages of Investment Casting

So what are the pros and cons of the investment casting process? Here, we list some of the known advantages and disadvantages of investment casting.

Advantages of Investment Casting

  • Investment casting is suitable for crafting small, complex geometric items with intricate features in a single mold.
  • Investment casting is a highly versatile technique. The process can be used to combine many wax patterns to produce one unique mold. Additionally, the process allows you to configure components that cannot be made using machines. This property makes it a better alternative to weldments.
  • The most notable benefit of the investment casting process is that it produces parts with precise dimensions and smooth finishes. Shells are formed around consistent patterns. This ensures no parting line is left behind, resulting in a smooth finish. Accordingly, a post-process can be used for a more refined finish.

Other advantages of investment casting include:

  • The material is reusable: Engineers can reuse the wax to make other patterns. The mold can also be reused due to its material strength.
  • High tolerance: The investment casting process has a .003″ tolerance. This is tighter than many casting techniques, such as die-casting.
  • Design capabilities: Engineers can easily incorporate markers, such as product logos and numbers, into the final product.
  • Easy to cast highly intricate components
  • It can be used to cast almost every metal
  • Utilizes metals effectively
  • The process does not pose risks to the environment

Disadvantages of investment casting

Despite having numerous advantages, the investment casting process has its drawbacks.

  • The most notable disadvantage of the lost-wax castingtechnique is that it is a bit costly, especially in short-term projects. The high-cost results from the use of specialized tools, refractories, and binders. Accordingly, many operations are needed to make a mold, while the labor required is also high. The occasional defects also add to the overall cost of the process. However, overall, investment casting is less costly compared to using machining processes to make similar parts.
  • Another disadvantage of investment castingis the size limit. Only a few designers can create large parts using investment casting. This makes it for clients looking to fabricate bulky parts.
  • Investment casting is suitable for casting small intricate parts. Components exceeding 75 pounds may require other casting techniques.
  • Additionally, investment casting shells cannot be smaller than 1.6 mm deeper. You may want to look for an alternative casting method if your casting design requires a core that does not fit into the above dimensions.
  • The investment casting process is more complex compared to other casting techniques. The process requires specialized equipment and preparations.

Other disadvantages of investment casting include:

  • Object requiring cores may not be easy to cast
  • You cannot make a hole smaller than1.6mm or deeper than 1.5 times the diameter.
  • The entire production cycle is longer compared to other casting methods
  • The quality management system is complicated due to many factors affecting the overall mold quality

Take-Home

From the details above, investment casting has proved to be a more advantageous process of making new products at minimal raw material usage and low cost. If you require any casting production, contact us, and we will sort you out with the most precise products.

Category: Blog