Investment casting is one of the best casting options for creating intricate parts. The manufacturing process makes use of a wax pattern coated with a refractory ceramic material, which is allowed to dry and harden. The wax is melted out and leaves an internal cavity to shape the final product’s geometry.
The application of investment casting is broad due to its unique benefits such as automotive, aerospace, power generation, military firearm, food, oil and gas, commercial, and energy industries. All these industries make use of metals manufactured with investment casting.
The technique is called investment casting because the workpieces are created around a shelled casting, which will be removed once the workpieces are poured into the mold. There are several steps involved in designing and creating the desired objects. Well, in this reading, we’ll explore what investment casting is, its applications, diagrams, advantages, disadvantages, and how it works.
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What is Investment Casting?
Investment casting, which is also known as “lost wax” casting, is a method of the precision casting process to manufacture small complicated parts, using almost all alloys. The process uses the replication of wax patterns to create parts. The term lost-wax casting is the modern way of describing the investment casting process.
The manufacturing techniques has been used in various forms for the last 5,000 years. Beewax was earlier used to form patterns necessary for the casting process. However, investment casting make use of more advanced waxes, refractory materials and specialist alloys used for the pattern.
Investment casting are highly in demand due to their ability produce components with accuaracy, repeatability, versatility, and variety of metals and high-performance alloy can be used.
Related: What is Die Casting? its Diagram & How it Works
Applications of Investment Casting
In the early stage, it was used by ancient Chinese and Egyptian culture to create artwork. Not until the development of the jet turbine engine at the end of world war II. Investment casting became an enabling technology in most industries today, their applications. The casting technique is of high demand due to strength and precision. It is popular in many industries including,
- Aerospace and defense
- Power generation
- Military
- Marine
- Automotive
- Oil and gas
- Space exploration
- Medical / orthopedics
- Agriculture
- Construction
- Commercial and consumer products.
Diagram of Investment Casting
How Does Investment Casting Works?
Investment casting involves creating a desired object through several steps, including creating a wax pattern, arranging the patterns in multiple wax patterns, and creating a gate device for metal or material to pass through. The tree-like arrangement of the wax patterns allows for multiple items in a single set.
A shelled casting is then added to the tree, dipped in ceramic slurry and fine sand. The mold is allowed to dry before proceeding to handle the casting stress. The wax is removed by heating it in an oven or steam, and the mold is placed upside down to allow liquid wax to flow out, creating new wax patterns.
Molten metal is poured into the shell, and the material remains in the casting until it cools and solidifies. The shelled casting is removed, leaving the original tree. The objects are carefully cut off, and imperfections are inspected for. These can be sanded, coated, smoothed, or machined to achieve the desired object. Learn more about investment casting and its process.
Things to Considered When Choosing this Casting Process
It is important to know the things it can offer before choosing it. these factors will lead to a succession of the production if the job truly suits the casting process. factors consider include:
Tooling cost: it is important to know and calculate the tooling cost before choosing any casting process. for example, casting items of low quantity in investment casting will be more expensive. So, it should be considered when pursuing a long impression. Payment for castings should be considered when determining if this casting offers greater values.
Size limitations: suitability for producing small parts. Big parts should not be performed on this process, unlike sand casting that is suitable for large parts. Items with small size and intricate shape should be done during this casting process.
Very small structures: this process is suitable for making thin-walled applications. However, the presence of cores can be difficult and challenging. Core typically cannot be smaller than 1/16 (1.6mm) and deeper than 1.5x diameter.
Timing: time to produce items should also be considered in investment casting. the multi-step way is more time-consuming.
Advantages of Investment Casting
Below are the benefits of investment casting:
High-Quality Finish: Investment casting can produce part 99.5% precisely while maintaining an excellent surface finish. This greatly reduced the need for additional surface finishing.
Complex Shape: With investement casting complex items can be produce. Majority of the items produce on this casting technique are often rejected by other casting methods.
Tight Tolerances: Investment casting produce parts accurately with tighter tolerance, which is why they are called precision casting.
Material Diversity: With investment casting, it is possible to cast almost any kinds of metals and alloys of varying melting points. for instance, aluminum, steel, cobalt, brass, etc.
Material Recycling: The mold material can be recycled and reuse for the next casting cycle. This will help save cost and time.
Related: What is Evaporative Pattern Casting (EPC)? Diagram & How it Works
Disadvantages of Investment Casting
Below are the limtations of investment casting:
Complex Process: Investment casting is a very complex process and will require a skilful perform to perform it.
High Cost: The process will cost must which why it is often done when casting are needed in bulk. It not suitable for casting needed in small quantity.
Time Consuming: Investment casting involve a lot of steps, making each casting cycle longer to accomplish.