Yihui Vacuum Casting Equipment | Precision Precious Metal Casting Technology Analysis

In the fields of high-end jewelry, dental orthodontic equipment, and precision cultural and creative jewelry casting, vacuum pressure casting technology is a benchmark production process for achieving ultra-high detail restoration, low porosity, and low oxidation loss in castings. Yihui focuses on the research and production of precious metal precision casting equipment, with a full range of vacuum casting equipment including AVC, DVC, and SVC, covering three levels of scenarios: store sampling, customized studio small-scale production, and large-scale factory production. It can perfectly adapt to special alloy materials such as platinum, K gold, foot silver, and dental copper alloys that are prone to oxidation and require high precision. This article rigorously disassembles the core technology system of Yihui vacuum casting from five dimensions: physical principles of vacuum pressurization, standardized complete process flow, equipment specific process advantages, objective limitations of processes, and key points of production quality control. It can provide professional references for jewelry casting technicians, factory process engineers, and equipment procurement practitioners.

Basic Physical Principles of Vacuum Casting

Core driving force of vacuum casting is negative pressure difference+bi-directional pressurization of inert gas, relying on the pressure difference to drive the complete filling of the metal melt, which is different from the traditional centrifugal casting's rotational centrifugal force forming logic. The entire casting process is divided into three physical stages: vacuum pumping, closed melting, and pressure filling. The entire process is stable and controllable, with strong process repeatability.

Negative pressure exhaust core logic

Seal and place the gypsum casting cylinder that has completed the roasting and wax removal on the pressure bearing workbench of the equipment. The vacuum pump synchronously extracts all the air in the casting cylinder cavity and gypsum pores, creating a stable negative pressure environment of 0.02-0.05MPa. By thoroughly emptying the cavity air, eliminating the air resistance when the molten metal enters the mold, and eliminating air cushion and holding problems, common process defects such as casting cold shut, insufficient pouring, and material shortage can be avoided from the source.

Anti oxidation mechanism of closed melting

Melting chamber of the equipment adopts a fully enclosed structure, and inert protective gases such as argon and nitrogen are automatically introduced before melting, completely isolating oxygen in the air and preventing metal oxidation at high temperatures. Relying on intermediate frequency induction eddy current technology to uniformly melt various precious metals, combined with Yihui's exclusive electromagnetic stirring system, the metal melt forms a uniform mirror rolling effect, achieving full fusion of alloy elements, effectively suppressing the loss of volatile alloy components such as zinc and palladium, greatly reducing the generation of oxide slag, and ensuring high purity of the melt.

Principle of differential pressure pressurization filling

Mold cavity maintains a continuous negative pressure state, and after the crucible flips, the molten metal flows smoothly into the sprue. The equipment synchronously outputs a positive pressure of 0.1-0.2 MPa of inert gas, and uses the pressure difference between the inside and outside to push the molten liquid to penetrate uniformly and uniformly to the smallest grain corners of the mold cavity. Compared to centrifugal casting, there are no issues of rotational eccentricity or uneven force distribution. The overall wall thickness of the casting is uniform and consistent, and complex three-dimensional patterns, multi-layer hollowing, and ultra-fine grain structures can be fully filled and formed in one go.

Exclusive optimization technology for Yihui equipment

Device is equipped with a digital intermediate frequency power supply, and the melting temperature control accuracy can reach ± 1%, accurately adapting to the melting threshold of different precious metals. Adopting Yihui customized segmented vacuum+pressure intelligent program, it can independently match the optimal negative pressure value, pressure duration, and holding time for different materials such as platinum, K-gold, and silver, achieving material specific process adaptation. The equipment is equipped with multiple safety mechanisms such as air leakage self check, over temperature shutdown, and pressure abnormality protection. The parameters of the vacuum system, melting system, and pressurization system are stored digitally and traceable throughout the process. The process stability and repeatability far exceed traditional simple vacuum casting equipment, completely solving the problems of large manual debugging errors and inconsistent batch quality.

Yihui vacuum casting standardized complete process flow (adapted to lost wax method)

Entire process forms a closed-loop standardized seven process, and the equipment touch screen can store hundreds of custom material process formulas. With one click calling and unified operation standards, it greatly reduces the threshold for manual operation and adapts to the needs of standardized mass production and fine sampling.

1. Welding and assembly of wax mold module

Produce standard wax parts based on product drawings, arrange wax trees and main and sub runners reasonably, and add auxiliary internal runners for complex three-dimensional parts, hollow parts, and thin-walled parts. Adapt to the universal specification of 5 "× 16" edgeless steel cylinder for equipment, optimize the flow path of metal melt, balance the filling speed, and structurally avoid problems such as local material shortage and incomplete filling of patterns.

2. Powder filling, mold embedding, and vibration curing

Using specialized precision cast gypsum for uniform infusion and complete wrapping of wax tree modules, coupled with a matching vibration table for high-frequency vibration, to thoroughly remove any air bubbles inside the gypsum. After the infusion is completed, let it stand at room temperature for 6-12 hours to ensure that the gypsum is completely hardened and dense, avoiding defects such as pitting and sand holes on the surface of the casting caused by loose gypsum and large pores.

3. Segmented gradient roasting for wax removal

Adopting a three-stage gradient heating roasting process: the liquid wax material is melted and discharged in the low temperature stage, residual carbonaceous impurities are completely decomposed in the medium temperature stage, and the gypsum cavity is sintered and hardened in the high temperature stage to ensure smooth and dense cavity. Strictly control the temperature at which the casting tube is taken out of the furnace to avoid sudden cooling of the high-temperature cavity and premature solidification of the molten metal entering the mold, ensuring the integrity of the filling process.

4. Sealed vacuum inert melting

Place precious metal raw materials into the equipment's built-in intermediate frequency crucible, seal the chamber and vacuum it, then fill it with argon gas to create an inert protective atmosphere. Accurate temperature control melting of different materials: Platinum 1700-1800 ℃, 18K gold 1100-1200 ℃, 925 silver 980-1050 ℃. By using electromagnetic stirring technology, we can eliminate alloy segregation and uneven composition, and ensure the purity and absence of floating slag in the melt, thereby guaranteeing the quality of castings from the melting process.

5. Integrated negative pressure pressurization filling

Lock the sealed casting cylinder, start the preset process program with one click, and the equipment automatically completes the entire process operation: first evacuate the mold cavity with vacuum, then the crucible automatically flips and pours the material, and synchronously apply inert gas pressure to assist in filling. The molten liquid flows smoothly, without splashing or eccentricity, completely filling all fine patterns and micro cavities, and achieving a high degree of detail restoration in the finished product.

6. Sealed slow cooling and shaping

After the filling is completed, the cavity is sealed and slowly cooled down to effectively release the internal stress of the casting, greatly reducing the risk of cracking and deformation of large, thin-walled, and complex hollow parts. The small casting tube adopts a natural slow cooling mode, and industrial production models are equipped with a water cooling auxiliary system, effectively shortening the production cycle of a single batch and improving production efficiency.

7. Post cleaning treatment and quality inspection

After roasting and cooling, the gypsum is crushed and the metal casting tree is taken out. There is no large area of impurity enrichment in the sprue area, and only a small amount of sprue waste can be recycled and remelted, with a low material loss rate. After simple post-processing such as sandblasting, grinding, and polishing, the quality inspection of castings can be completed. The occurrence rate of defects such as porosity, pitting, cold insulation, and deformation is significantly reduced, and the yield rate is significantly improved.

Technological advantages and applicable scenarios

Relying on the three core advantages of negative pressure exhaust, sealed oxidation prevention, and uniform pressure difference filling, vacuum pressure casting has become the preferred process for high-end precision precious metal castings. Yihui vacuum casting equipment has been upgraded through three core technologies: digital intermediate frequency precise temperature control, segmented intelligent vacuum pressurization program, and fully automatic safety protection system. It specifically solves the industry pain points of unstable vacuum degree, high metal oxidation loss, poor batch process repeatability, and low yield rate in traditional simple vacuum machines.

During the production process, precise matching of the three core parameters of vacuum degree, pressurization pressure, and melting temperature, combined with standardized roasting, mold embedding, and wax removal processes, can stably produce high-purity, high detail, and low loss precision precious metal castings. The equipment is widely suitable for high-quality and high-precision production scenarios such as high-end jewelry customization studios, platinum precision casting dedicated factories, dental precision alloy manufacturing, and mass production of high-end cultural and creative jewelry.

Yihui Casting Technology Co., Ltd. was established in 2003. After more than 20 years of accumulation, Yihui has now developed into a national high-tech enterprise that integrates research and development, production, sales, consulting, installation, and training of lost wax casting equipment, and provides one-stop solutions for metal casting. Yihui Casting Technology products include metal casting equipment, casting wax, graphite products, quartz products, etc., which are exported to Southeast Asia, the Middle East, Europe, America and other regions. The company has its own R&D team, which independently develops and produces automated vacuum die-casting machines, G20 vacuum bead scattering machines, and intelligent system D3 vacuum pressure casting machines, breaking the industry's long-standing dependence on imported high-performance jewelry equipment.

For more information about Yihui Casting Technology Co., Ltd., please visit our official website or contact our team.

website: www.yihuicasting.com      email : info@yihuicasting.com     whatsapp : +86-13802830498