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In the jewelry manufacturing industry, 3D wax printing machines have gradually replaced traditional manual wax carving and some CNC processes, and have become an important tool in modernized production. Using high-precision jetting technology, wax printers deposit wax materials layer by layer, and rapidly create wax models with fine details and smooth surfaces. Then, these wax models are used for lost-wax casting. As a result, high-quality metal products are produced. In the whole printing process, the most critical materials are red wax and white wax.

Composition and Properties of Red Wax

Red wax is typically used as the primary material for printing the main body of jewelry models. It is made from a combination of synthetic wax, photosensitive wax, and a small amount of resin modifiers. This combination gives red wax sufficient hardness to maintain stability, and show the delicate details of printed shapes in the printing process. More importantly, during high-temperature casting, red wax burns almost completely clean and hardly any residue is left. This character guarantees the purity of metal surface in the lost-wax casting process, and prevents quality problems such as pores or inclusion as well. As a result, red wax is widely used as the main material for creating complicatedly designed jewelry such as rings, earrings and pendants in the jewelry industry. Especially for pieces having intricate structures like openwork and filigree, red wax can perfectly reproduce designers' creation, which makes the finished products are precise and beautiful.

Functions and Properties of White Wax

In contrast, white wax is not directly used in the finished product, but it is specifically used as a support material to assist in the printing process. Its composition typically consists of low-melting-point wax, and sometimes soluble polymers may be added into some formulations, giving it a soft and easily removable nature. During the process of printing, white wax is formed under, inside the walls, or around overhanging parts of the model to support the main red wax model. In this way, even highly complex or overhanging structures can be successfully printed without collapsing or deforming.

Methods for Removing Support Material

Once its supporting role is completed, white wax must be completely removed. This step is typically accomplished through heating to melt the white wax or dissolving it with chemical solvents. And this can ensure the delicate and smooth surface texture of the main model body.

Cooperation of Red Wax and White Wax in Printing

The different roles and cooperation between red wax and white wax form a very stable combination in jewelry 3D printing. Red wax ensures the quality and casting ability of the wax model, while white wax ensures the structural stability and precision during printing. It should be noticed that the adhesion between red and white wax is carefully designed: during printing, it is strong enough to support the model, but it is not so strong that red and white wax are difficult to separate. This balance is important for successful and smooth wax printing.

Storage Conditions for Wax Materials

Both red and white wax have very strict requirements for environmental conditions. They should be stored in an environment which is temperature-controlled, dry, and without direct sunlight. The storage temperature should be between 18-28℃(64-82℉), and the relative humidity should be 40-60%. The wax materials may be softened or deformed in a hot environment, leading to reduced printing accuracy. And the wax materials may absorb moisture in a humid environment, affecting printing stability. In addition, wax materials should be kept in sealed containers to prevent dust or impurities from entering. Otherwise, the printer nozzles may be blocked, or the finished products’ surface may have defects. Wax materials should be handled gently when moving them, as they are brittle and can crack or break if dropped or impacted. 

Factors to Consider When Choosing Wax Materials

When making jewelry, wax models printed by 3D wax printers are used for lost-wax casting. The process is: a wax model is surrounded by a hardened material. And then, when the wax model is baked at high temperatures, the hardness of the shell is fixed, and the wax model inside is melted and vaporized. At last, the hardened shell becomes the mold for molten metal. This process requires wax materials of high quality.
Focus on three key factors in selecting third-party wax:

Ash content: 

Wax materials with low ash or no ash should be chosen to avoid ash or residues inside the mold after burnout. If other wax materials is chosen, thorough cleaning for the mold is needed.

Shrinkage rate: 

Special attention should be paid to the shrinkage coefficient in the technical data. And materials with a low shrinkage coefficient should be chosen to minimize dimensional errors.

Water absorption: 

Wax with low water absorption should be chosen to extend the storage life of materials and wax models.

Frequently Asked Questions (FAQ)

1. Can red wax be used as a support material?

Generally, no. Red wax has high hardness and is difficult to remove, so this makes it easy to damage the main model. Therefore, it is only suitable for printing the main body of the model. Generally, white wax plays a role in supporting structures. 

2. How can white wax residue be avoided?

In the process of removing the supporting wax, it’s important to strictly control the heating temperature to prevent the red wax from softening. Meanwhile, using a compatible cleaning solvent and rinsing thoroughly can effectively reduce white wax residue. If any residue remains, it’s necessary to use a magnifying glass or a microscope to carry out a secondary cleaning.

3. How long can a red wax model be stored?

Generally, red wax models can be stably stored for several months or even over a year, if stored in an environment which is temperature-controlled, dry, and without direct sunlight, and the models are not excessively handled. However, long-time storage may result in slight surface aging, so it’s recommended to cast the wax model as soon as possible.

4. Does the ratio of red wax to white wax affect the final product?

Yes, it can have a certain impact. Lack of support may cause the model to collapse during printing, while excessive support increases cleaning difficulty. Therefore, the red wax-to-white wax ratio should be properly set in accordance with the model’s structure. This is one of the key tasks for automatic optimization of most wax printing software.

5. How can the red wax model be protected during white wax removal?

It’s recommended to heat white wax at a low temperature or gradually dissolve it, and avoid a one-time high-temperature treatment. Meanwhile, when taking out the wax model, it’s recommended to use soft tweezers or specialized tools to avoid scratching the surface.

6. Is red wax suitable for all types of jewelry designs?

It’s very suitable to use red wax to make highly detailed and complex structures. However, when producing very large or thick designs, shrinkage risks may happen during casting. In such cases, it’s necessary to appropriately adjust the model structure or make compensations based on the experience of skilled artisans.