Lost Wax Casting is also termed as 'investment casting,' 'precision casting' or 'cire-perdue.' It is a widespread process of metal casting that has been used for a long time. It is the process by which any metal can be created or formed in a shape using a wax model. It radiates an initial model or design to make things in various metals, such as silver, gold, bronze, stainless and carbon steel, nickel, cobalt, aluminum, copper, or brass. In this process, liquid metal is streamed into a mold created from a wax model. Low Wax Casting is used as an industrial method in engineering and manufacturing to assemble accurate metal pieces. This process is now being used in Jewelry design. In Rananjay Exports, the Lost wax process in gemstone jewelry manufacturing is used for making the best jewelry designs.
Investment casting or Lost Wax Casting is a metal-forming procedure that has been in use for over 6,000 years. Artifacts such as sculptures and furniture made with lost wax casting have been found in Egypt, Nicaragua, Vietnam, Israel, Mediterranean, Nigeria, and the Indus Valley. The oldest and famed lost wax-cast object, an idol or talisman, was created in the Indus Valley, which is around 6,000 years old.
It is mainly used nowadays to produce dentistry, jewelry, inlays and onlays, knee and hip implants, automotive, rail, mining, aerospace, and other art forms. Around the world, in regions such as Pakistan, Egypt, East and South Asia, Africa, Greece, Europe, etc., entities made via this method have been found.
Process Of Lost Wax Casting
Firstly, there are numerous equipment and materials used in this process. Some safety types of equipment must be worn while performing this process. The material and equipment used in the process of Lost Wax Casting are Safety gear: protective glasses and leather gloves; Wax: microcrystalline, paraffin, or beeswax; heat gun and texturing tools; casting metal; gram scale; volumetric flask for water, vacuum chamber, kiln for burnout, crucible, flux, torch, etc. Without using these types of equipment and materials, it will become hazardous.
Models can be created of either the wax model itself (direct method) or a wax copy of a non-wax model (indirect method). The process used in investment casting, or precision casting, is as follows:
Creating A Model:-
Creating a model starts with an artist or mold-maker who uses materials like wax, clay, or other similar substances to craft an original design. The wax model is then shaped using a soldering iron, texturing tools, and a heat gun. It's important to note that the size and complexity of the wax model are limited by the wax carver's skill and the casting equipment's capacity. Designs may also need to be improved by the disorder to allow the molten metal to flow into the mold. This is especially crucial if your method includes small, intricate elements that may not fill with metal during the casting process.
Making a Mold:-
After constructing a model, the next step is to make a mold around it. The rigid exterior mold is usually made of fiberglass or plaster and supports a soft inner mold made of polyurethane rubber, silicone, or latex. This internal mold helps to imitate the shape of the actual model. If there are any lengthy, narrow extensions on the model, they are often removed and molded individually. Sometimes, several molds are needed to recreate the original model, especially for enormous models.
A mold is first created to make a wax miniature of an object. Once the mold is ready, molten wax is poured into it and stirred around until it covers its internal surface evenly. This procedure can be repeated multiple times to form the actual design. Alternatively, the entire mold can be filled with molten wax and left to cool until a desired thickness has started on the exterior of the mold. Then, the rest of the wax is poured out, the mold is turned upside down, and the layer of wax is allowed to cool and harden.
Removing the hollow wax model from the original mold is a crucial step. It must be done with utmost care to avoid any damage. If the mold is durable enough, it can be used repeatedly to make multiple copies of the sculpture. One method to remove the wax is to heat it in short bursts in a microwave until it completely drips into a small container. On the other hand, the wax can be burned out in a kiln.
Firstly, the wax model is given its final shape by rubbing it with a heated metal tool. Any imperfections are smoothed by dressing the mold, making it look like the original. Wax pieces molded independently can be heated and joined together to form the final product. Foundries often use registration marks to indicate the exact placement of separate wax pieces.
The next step in the process is spruing the wax. The sprue, which is also made of wax, acts as a channel for the molten bronze to flow into the mold. The spruing process is carefully planned and usually starts at the top of the wax copy with a wax "cup." Wax cylinders attach the cup to different points on the wax copy. The sprue does not need to be hollow because it will be melted out later.
Dipping Wax in Slurry
The process of creating a ceramic mold involves immersing a wax mold copy into a mixture of silica slurry and dry crystalline silica, also known as grit. This combination forms a ceramic shell mold that is half an inch thick, with thicker shells required for larger pieces. The entire structure is coated with this ceramic shell, except for the inside of the cup. The cup's flat top is the piece's base during the process. Furthermore, the core of the mold is filled with fire-proof material.
Hardening The Silica
To harden silica, the piece is placed inside a kiln. The heat inside the kiln sets the silica to create a shell while the wax melts and is lost. After this process, all that remains is the shell with space, which was earlier occupied by wax. Recovering and reusing the melted wax is possible, but it is often burned up. Now, the original artwork is reduced to negative space inside the hardened ceramic shell, along with the feeder, vent tubes, and cup, which are also hollow.
Testing with Water
After allowing the ceramic shell to cool down, checking whether the water flows smoothly through the vent and feeder tubes is crucial. If there are any leaks or cracks, the mold-makers can fix them by using thick refractory paste. The cracks or leaks can be patched with the same paste. One can drill holes into the shell and then restore them to check the thickness.
Pouring Molten Metal
It's finally time for the pour, but before that, the shell must be heated to eliminate any moisture. This is also necessary to ensure it is hot enough to pour the melted bronze since a cold surface will break due to the temperature difference. The metal is dissolved in a crucible inside a furnace and poured carefully into the shell. The shell must be hot to avoid shattering due to temperature differences. After pouring, the filled shells are allowed to cool down.
A hammer releases the casting to remove the shell, and the sprues are cut off. Afterward, the artist works on the casting to remove any details resulting from the casting process. This step is crucial to ensure the sculpture looks like the original model. The sprues, which are also carefully recreated in metal, are cut off, and the material is then reused in another casting.
Give Finishing To Your Piece:-
When working with solid metal casts, it's essential to take the necessary steps to finish the piece properly. One of the first things you should do is to scrub away any excess mold material in water, which will help to reveal the proper form of the casting. You may need to break off the casting gates with clippers for smaller objects, while larger pieces may require an angle grinder. Once the excess material is removed, you can polish or patina the metalwork to give it color and dimension and achieve the desired finish.
So, the above written is the complete steps of the process to be followed in the Lost Wax Casting. Moving ahead to the end of the content, we must know the significance of Lost Wax Casting in the Jewelry industry.
Lost Wax Casting in the Jewelry Industry
The lost wax process can be used with any material that can burn, melt, or evaporate, leaving a mold cavity. Jewelry casting is an ancient art that has been around for thousands of years. It involves melting and pouring metal into stone, plaster, sand, or cuttlefish bone cavities. Skilled artisans then remove the castings from their encasement and shape them into beautiful adornments.
Regarding small parts and jewelry, the casting methods differ slightly from those used for sculptures. A wax model can be obtained by injecting it into a rubber mold or customizing it through carving. The wax or waxes are then sprued and fused onto a rubber base called a "sprue base." Most sprue bases have a circular rim that grips the standard-sized flask, holding it in place. Refractory plaster is composite and flows into the flask. It is then allowed to harden and burn out, as outlined above. Casting is usually done straight from the kiln by centrifugal or vacuum casting.
Rananjay Exports is one of the leading wholesale gemstone jewelry manufacturers and suppliers. One can find Alphabet Jewelry, Casting Jewelry, Custom Jewelry, Handmade Jewelry, Designer Jewelry, and Gemstone Jewelry in one place. The company is an OEM Jewelry and ODM jewelry manufacturer. They also use the Lost wax process in their gemstone jewelry. Rananjay Exports is the best company that provides you with jewelry according to your wants and demand at wholesale price. So, if you want jewelry produced with authenticity and using the ancient process of Lost Wax Casting, you must check out the Rananjay Exports website.