Unveiling the Advanced Lost-Foam White Pattern Process

2026-02-27

The newly adopted lost-foam white pattern technology, also known as expendable pattern casting (EPC), represents a revolutionary advancement in modern foundry practices. Unlike traditional sand casting, this innovative process eliminates the need for sand cores and parting surfaces, enabling one-step molding of complex components with exceptional accuracy . The core workflow of the white pattern process includes four key stages:

Pre-expansion: Expandable polystyrene (EPS) or STMMA beads are heated to 80-100°C in specialized equipment, expanding to form low-density, closed-cell foam particles with a density of 18-25g/L . This step ensures uniform particle size and structural stability for subsequent molding.

Aging Treatment: The pre-expanded beads undergo a controlled aging process in sealed chambers, where air and inert gases are introduced to balance internal and external pressure . This critical phase enhances the beads’ elasticity and shrinkage resistance, ensuring dimensional stability of the final pattern.

Molding & Assembly: The aged beads are injected into precision aluminum molds and reheated with steam, causing secondary expansion to fill the mold cavity completely . The fused beads form a seamless foam pattern (white pattern) that matches the exact shape of the desired casting. Multiple patterns are then assembled into clusters using high-temperature-resistant adhesives.

Refractory Coating & Drying: The foam clusters are coated with a ceramic refractory material via dipping or spraying, forming a 0.5-2mm protective layer . After drying at 40-50°C, the coated patterns are ready for the casting process, where molten metal replaces the vaporized foam to form the final component.

Core Advantages of Lost-Foam White Pattern Technology

Compared to conventional casting methods, Anhui Xinhong’s new process offers distinct competitive edges:

Superior Precision: Achieves dimensional tolerances of CT8-CT10 grade and surface roughness of Ra 6.3-12.5μm, reducing post-machining work by 30-50% .

Cost Efficiency: Dry sand is recyclable at over 90%, while metal utilization rate increases by 10-15% due to optimized gating system design .

Environmental Friendliness: Eliminates wastewater and minimizes dust emissions, with foam vapor treated to meet green manufacturing standards .

Design Flexibility: Capable of producing complex components (e.g., engine blocks, valve bodies) without sand cores, shortening production cycles by 20-30% .

Driving Industry Innovation and Sustainable Development

"The commissioning of the new white pattern molding equipment demonstrates our commitment to technological upgrading and quality improvement," said a representative of Anhui Xinhong Machinery. "By adopting advanced lost-foam technology, we not only enhance production efficiency and product precision but also contribute to the industry’s shift towards green and sustainable manufacturing."

With the new production line in full operation, Anhui Xinhong Machinery is well-positioned to meet the evolving needs of domestic and international clients. The company will continue to invest in R&D and equipment modernization, striving to become a global leader in high-precision casting solutions.

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Unveiling the Advanced Lost-Foam White Pattern Process

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2026-02-27