Jewelry casting porosity and sand hole solution | Yihui precious metal precision casting improves yield rate

Is it difficult to cure the porosity and sand holes in castings? Yihui's casting solution can help you improve your yield rate. In the precision casting industry of precious metal jewelry, porosity and sand holes are typical defects that production faces for a long time. Once a hole problem is detected in the casting quality inspection, the finished product can only be scrapped or reworked, which not only causes loss of precious metal raw materials, but also delays order delivery and continues to increase production costs. Many workshop technicians repeatedly adjust the melting and casting temperature and pouring speed, and the defects can only be temporarily improved, only to recur after a period of time. At its root, most factories only focus on single point parameter adjustment of molten gold casting, ignoring the hidden dangers buried in the front-end process. The formation mechanisms of pores and sand holes are different, and in order to solve defects in a long-term manner, a systematic casting solution covering the entire process is needed.

01. Distinguish between two types of defects and identify the root cause of the problem

Pores are mainly formed by gas retention inside the casting during the production process. Residual bubbles in wax molds, insufficient exhaust during gypsum mold baking, and insufficient vacuum during the melting and casting stage can cause air to envelop the molten metal, resulting in the formation of internal voids after cooling.

Most sand holes originate from gypsum molds. Unreasonable gypsum ratio, insufficient strength of the mold shell, sand falling off the inner wall of the cavity during the pouring process, gypsum impurities mixed into the metal liquid, forming sand holes on the surface or inside of the casting. Inadequate control over any stage of wax making, mold making, or roasting can lead to sand hole defects.

Casting belongs to a continuous and complete process system, and defects are often caused by the superposition of multiple processes. Simply adjusting parameters at a single point can only treat the symptoms without addressing the root cause.

02. Pre control of the full chain solution to reduce defects and hidden dangers

Yihui is deeply involved in the field of precious metal precision casting equipment, and aims to create a one-stop jewelry casting solution for the pain points of the jewelry casting industry, connecting the entire production chain of wax injection, mold making, baking, and vacuum melting casting.

In the front-end process, use vacuum wax injection equipment to produce dense wax molds, reducing the bubbles that come with the wax molds. At the same time, standardized process guidance is provided to standardize the gypsum ratio, molding operation, and roasting temperature curve, improve the strength of gypsum mold shell, fully discharge the gas inside the mold, reduce the hidden dangers of sand and gas accumulation from the source, and lay a good foundation for subsequent melting and pouring.

03. Core advantages of DVC-III fully automatic vacuum casting machine

Melting and pouring are the core processes that determine the quality of castings. The Yihui DVC-III fully automatic vacuum casting machine is the core tool for the entire solution to overcome porosity and sand holes.

✅ Vacuum sealed melting environment, source suppression of porosity

The whole machine is melted and poured in a vacuum chamber, isolated from air; Optional argon gas protection can reduce the oxidation of precious metals, eliminate gas entrapment in metal liquid, solve the problem of gas entrapment in traditional open melting, and significantly reduce casting porosity.

✅ DSP intermediate frequency digital power supply, precise temperature control, reducing sand holes

Our self-developed DSP intermediate frequency digital power supply has a temperature control accuracy of ± 1%, combined with electromagnetic stirring, ensuring uniform composition of the metal liquid without local overheating. Smooth melt reduces erosion of gypsum mold cavity, minimizes sand loss and sand hole formation, reduces melting loss to 0.02%, and ensures pure casting quality.

✅ Programmable automatic pressure casting, stable batch quality

Support the storage of multiple sets of process formulas, and independently set vacuum, melting, pouring, and pressurization parameters for products such as K gold, foot silver, antique gold, and filigree. Pressure casting achieves smooth filling of molten metal and reduces sand loss caused by mold shell impact; Parameters can be called repeatedly to weaken reliance on manual experience and ensure consistent quality of batch castings.

✅ Intelligent self checking protection to prevent batch defective products

Equipped with a fault diagnosis module, it automatically shuts down and provides a pop-up warning when it detects air leakage or vacuum abnormalities in the steel cup, avoiding the mass production of defective parts such as air holes and sand holes under abnormal working conditions. Multiple protections reduce material loss and production risks.

✅ Wide material adaptability, dual-use for sample production

Single maximum melting capacity of 2.5kg, compatible with gold, K-gold, pure silver, and copper alloys; The formation of filigree, hollow, plain circle, and relief jewelry is stable and the details are well restored, while meeting the needs of small batch sampling and large-scale production.

The entire solution can be coordinated with supporting equipment such as intermediate frequency melting machines and graphite crucibles to meet the production capacity needs of different factories.

04. Dual guarantee of hardware and process services, worry free landing

Good equipment cannot do without supporting processes. Yihui not only provides casting hardware equipment, but also has a professional technical service team. We will customize exclusive process parameters based on the product type and mold conditions of each factory, provide on-site debugging and operation training, investigate hidden problems on the production line, and solve the pain point of many enterprises' "purchasing equipment but unable to keep up with the process".

After many cooperative jewelry factories implemented Yihui's complete casting solution, the incidence of porosity and sand hole defects in castings significantly decreased, precious metal losses were controlled, the yield rate of castings steadily increased, and the pressure of rework and scrap was significantly reduced.

Stability is the core guarantee of production capacity in jewelry casting production. The repeated occurrence of pores and sand holes is essentially due to the shortcomings in the entire production chain. Yihui's one-stop precision casting solution, with dual support of hardware equipment and process technology, controls casting defects from the source, helps jewelry factories reduce scrap and precious metal losses, and achieves stable and efficient production.

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