Transforming a variety of metals from simple to complex objects by casting an original pattern is termed lost wax casting. This metal-forming technique is known for decades and widely used in producing ornaments, and dentistry. It is a method of choice for the production of metal parts in engineering and manufacturing due to its high precision.
What is Lost Wax Casting?
Lost wax casting is the process that involves the formation of a duplicate metal sculpture from an original sculpture. This process of casting a single metal object from a wax model is also known as Investment casting. The high precision and accuracy make it an ideal method for manufacturing objects with thin walls, close tolerances, and complex details.
It has been famous in the fine art and manufacturing world for over 6000 years. The metal casting technique is immensely used in agriculture, medical and automotive industries. The process involves pouring molten metal into a mold, once it is made the wax is melted and drained away. Inserting a heat-proof core has a key role in preventing the molten metal from totally filling the mold.
How does it Work?
The lost-wax casting process may fluctuate with the shapes, sizes, metal, industry, and intended application. Creating cast parts from the wax model comes under the direct method.
However, the formation of cast parts from replicas of the original wax model is termed as an indirect method. The direct method eliminates the need for creating a mold and producing a wax pattern.
The general process of metal casting involves the following steps;
You can create a customized design in wax before putting a mold around it. Then use the texturing tools, soldering iron, and heat gun to shape the model. When it comes to shaping the pattern, consider the shrinkage that will occur as the metal cools. The casting equipment employed and the skills of the artists decide the size and complexity of the model.
Plaster and silica are used in combination in the formation of mold which is responsible for giving the mold support and high refractory respectively. Measure each ingredient on a gram scale and mix them with water to give it a consistency of heavy cream.
Inject the molten wax in the rubber molds from a specific design. The pouring of the molten wax into the molds can be done over and over again from replicas of the original design. To remove the wax, the easiest method is heating the short bursts in the microwave.
Mixtures of elements possessing the best mechanical properties are alloys. When it comes to metal casting, ferrous and non-ferrous alloys are top on the list. Alloys differ in their physical and chemical properties which explains why different alloys melt at different temperatures.
The solid alloy is placed in a crucible where it is subjected to heating over an open flame in small segments. A furnace can be used if heating is required for larger amounts of solid alloy.
The molten metal is poured or injected into the mold cavity and allowed to solidify before proceeding to the next step. Great care must be observed when dealing with molten metal. It is essential to ensure the workplace is well-ventilated and the workers dealing with molten metal are wearing protective clothing.
Remove the metal from the mold after ensuring the metal is cooled and solidified enough. After removing the metal, quench the plaster in water to get rid of the mold. The final step involves finishing and polishing your solid metal cast.
Traditionally, this metal-forming process was associated with artisanal handcraft. In the modern world, creators are using the lost wax casting in combination with digital design and 3D printing which helps save time, energy, and cost.
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