Lost wax casting process

Lost wax casting is an advanced casting technology used in many fields thanks to the outstanding advantages it brings. However, not many people clearly understand the lost wax casting process. So let's learn about the lost wax casting process and the necessary equipment for each process with VISC through the article below.

The lost wax casting process can vary depending on the industry and application, but it generally includes the following steps:

• Wax modeling stage
• Steps to create the mold shell: dotting paste and sanding zirconium powder
• Drying and wax release process
• Casting stage
• Post-casting stage

1. Wax modeling and mold making stage

1.1. Create wax models:

• At this stage, the designer will create the design and shape the wax model using texturing tools, soldering irons and heat guns. Hollow out your wax model if possible.
• When shaping the sample, it is necessary to ensure any expected shrinkage as the metal cools. Patterns can also be closed with channels to allow molten metal to flow into the mold. This is especially important if the design contains small intricate details that may not be filled with metal during the casting process.

1.2. Mold making stage

• Creating a mold: After being designed, the wax model will be cast and polished to create the "master" model. The main model used to make wax molds is rubber or uses a combination of plaster and silica.
• Wax pattern production: Wax, in a semi-liquid state, is injected or poured into a mold to form a wax pattern, which is adjusted to allow contraction. This process can be repeated as many times as necessary depending on the number of parts to be molded.
• Assembling the wax pattern: The wax patterns are connected to create a tree-like structure with a hanging stem, providing a path for the molten wax to flow out and the molten metal to later fill the cavity. Once completed, the wax tree will be hung on a shelf.

1.3. Technological equipment for wax modeling process

Equipment for the wax modeling and mold making process provided by VISC includes:

2. Mold shell creation stage: cover with Zirconium paste and sand

The wax sample is washed, then dipped in paste and covered with Zirconium powder sand. This process is repeated 2-3 times until the highest quality wax shell is created.

Equipment for mold shell making process

3. Drying and wax release stage

To perform this step, the wax mold is dried naturally and then placed in a wax release machine. Here, under high temperature, the wax layer melts and evaporates. Then the mold continues to be removed from steam and remaining wax.

Wax drying and draining line equipment

4. Casting stage

The molten mold is further heated in a furnace to reduce the temperature difference with the molten metal. The metal is melted and then poured into a mold, using gravity or vacuum pressure to pull the metal into the cavity.

Casting equipment

5. Processing stage after casting

• Demolition: After the molten metal cools, the mold is transferred to the shell breaker, then moved to the cleaning stage. The stubs are cut off and recycled, while the molded parts are cleaned to remove signs of the molding process.
• Finishing: Cast parts are filed, ground, machined or sandblasted to achieve the final shape and surface finish. When necessary, molded parts are also heat treated to enhance the mechanical properties of the material.

Equipment for post-casting processing

Hopefully, the information provided by VISC from the above article has helped you clearly understand the lost wax casting process and the necessary equipment. If you need advice or learn more about flow molding technology, please contact us.

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VIETNAM INDUSTRIAL SERVICES AND SOLUTIONS JOINT STOCK COMPANY

Office Address: B4-12 Vinhomes Gardenia, Ham Nghi, Cau Dien, Nam Tu Liem, Hanoi.

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