Investment casting wax materials are constantly innovating, promoting the upgrade of precision manufacturing.
Recently, with the increasing requirements of the manufacturing industry for the quality and production efficiency of precision castings, the field of investment casting wax materials has ushered in many new developments. Investment casting is an advanced near-net molding process, and the performance of wax materials is directly related to the accuracy, surface quality and production stability of castings. At present, different types of investment casting waxes are accelerating innovation in the direction of high performance, environmental protection and customization.
There are currently a variety of investment casting waxes to choose from. The type of wax depends on a variety of factors, including fluidity, whether the wax can be recycled, dimensional consistency, surface finish, and application requirements. The following are several types of waxes, including filled model wax, non-filled model wax, runner wax, water-soluble wax and sticky wax.
Filled model wax
Filled model wax is a type of investment casting wax with added fillers. These fillers can provide certain properties to castings to ensure their strength, dimensional stability, low thermal expansion rate and minimal shrinkage. The types of fillers used in filled model waxes vary by supplier, but some common fillers may include bisphenol A (BPA), organic fillers, terephthalic acid, and cross-linked polystyrene.
Filled model waxes can be used for both small and large wax pattern production. Two major advantages of these waxes are their low thermal expansion and minimal shrinkage. They do not require a wax coolant to be placed in the pattern cavity to prevent shrinkage as the wax solidifies.
This type of wax is often used when you want tighter dimensional control over the part or assembly being manufactured and need to use a wide range of injection temperatures. Due to the addition of fillers, some wax may remain in the ceramic shell after the dewaxing process because the wax takes longer to burn out. The recovery and reuse of filled model waxes may vary depending on the density of the filler material.
Unfilled wax patterns
Unfilled wax patterns, or unfilled wax pattern mixes, have less filler material. These wax patterns have stable mechanical and thermal properties. They are typically used for small to medium-sized wax patterns with complex geometries and well-defined contours. Unfilled wax patterns have excellent flow properties.
The main advantage of unfilled wax patterns is their high surface quality. As a result, ceramic molds have fewer cracks and defects. In addition, it can be completely dewaxed from the ceramic shell for recycling.
Care must be taken when using unfilled wax patterns in the investment casting process. Due to the slower solidification rate, the surface of the pattern may sink. In addition, depending on the temperature of the wax pattern, the cross-section of the pattern may shrink undesirably. Depending on the part configuration, a wax pattern coolant may be required to avoid material shrinkage.
Runner wax patterns
Investment casting companies use runner wax pattern mixtures when superior mechanical strength and lower viscosity are required. This wax has a lower melting point than pattern wax. Therefore, during the dewaxing process, the wax flows completely out of the ceramic mold without the need to use higher temperatures.
The advantages of runner wax are its good weld strength and minimal thermal expansion coefficient. Workers can handle the wax without worrying about the part breaking in the ceramic mold. The wax pattern needs to be immersed in water and stored until it is completely solidified.
Water-soluble wax
Some parts and components require complex and precise internal designs. Therefore, precise cores must be set inside the wax pattern. To create these cores, water-soluble wax is required. Once the core is complete, it is placed in the wax mold, and then the model wax is injected into the mold. When the wax mold cools, the model is placed in a water and acid bath to dissolve the water-soluble core inside the wax mold.
Sticky wax
Sticky waxes are often used in installation and finishing processes. These waxes help to bond different model waxes together, or are used to assemble gates. The wax helps to form a strong bond with the parts, allowing them to withstand the operations of workers when making ceramic shells.
Looking to the future, investment casting wax materials will continue to innovate and develop around green environmental protection, high-performance customization, intelligent production adaptation and other directions, injecting strong momentum into the precision casting industry's move towards digitalization, intelligence, and greening, and supporting more products in more fields to achieve performance leaps and manufacturing upgrades.