China Shell Mold Casting Foundry
Simis Shell Mold Casting Foundry
Shell Mold Casting Factory Introduction
SIMIS Shell Molding Foundry specializes in the production of high-precision, small to medium-sized metal components using the shell mold casting (Resin Coated Sand Casting) technology.Our advanced equipment and stable process control deliver high dimensional accuracy, superior surface quality, and efficient production, making shell mold casting ideal for high-accuracy, medium-volume needs.
Resin-Coated Sand Production: Our line features automatic control over temperature and resin ratio, ensuring consistent sand quality.
Shell Forming: We use specialized Shell Mold Forming Machines with heated metal tooling, which allows for fast curing and high mold repeatability.
Melting: Multiple Medium-Frequency Induction Furnaces (500 kg, 1 t, 2 t) handle various steel/iron.
Pouring: Automatic Pouring Systems provide precise control over temperature and flow, complex mold filling.
Casting Weight: 0.5 kg – 100 kg
Maximum Dimensions: up to 800 mm × 600 mm × 400 mm
Surface Roughness: Ra 3.2 – 12.5 μm
Dimensional Accuracy: CT6 – CT8
Wall Thickness (Min): 3.0 mm – 5.0 mm
OEM Custom Shell Mold Casting Parts
Simis Shell Mold Casting Process
Shell Mold Casting Process Overview
Shell mold casting is a high-precision method that creates a hard, thin shell mold using specialized coated sand and heat. Molten metal is then poured into this shell to produce complex, high-precision, small to medium-sized castings.
The shell mold casting process offers high mold dimensional accuracy, excellent surface quality, and strong consistency. It is ideal for mass-producing parts with strict requirements, such as valve bodies, pump housings, and mechanical components, and is widely used in the automotive, machinery, and engineering sectors.
1. Mold Design and Manufacturing
A metal pattern (usually cast iron or steel) is produced based on the required casting design. This pattern dictates the final mold cavity shape.
2. Coated Sand Preparation
Coated sand is prepared by mixing quartz sand with a thermoplastic or thermosetting resin. This mixture provides superior fluidity and molding properties.
3. Heating the Metal Pattern
The metal pattern is preheated evenly to a specified temperature (typically 250–350°C). This consistent heat is critical for curing the sand shell effectively.
4. Sand Filling and Curing
The coated sand is injected into the heated pattern, filling the cavity via vibration or gravity. The sand quickly softens and cures upon contact, forming a hard shell of uniform thickness. Excess uncured sand is removed by flipping the pattern.
5. Shell Demolding
Once the shell is cured, the pattern's parting surface is opened, and the formed sand shell mold is carefully removed.
6. Shell Assembly and Bonding
The upper and lower shell halves are bonded together using adhesive or heat, ensuring a tight, leak-free closure. If needed, prefabricated sand cores are placed inside the mold cavity before assembly.
7. Mold Preparation and Pouring
The assembled shell mold is secured on a pouring platform or in a flask to prevent movement. Molten metal (such as steel, iron, or aluminum) is then injected through the designed runner system.
8. Cooling and Demolding
After the molten metal solidifies, the shell mold is broken away to remove the casting. The shell becomes brittle during cooling, making it easy to fracture and remove.
9. Casting Cleaning and Post-Processing
Residual sand and surface oxide scale are removed via shot blasting or sand blasting. The pouring system (gates and risers) is cut off, and the casting undergoes final grinding, finishing, and size inspection.
Available Materials for Simis Shell Mold Casting Foundry
What metal parts can be cast in Simis Shell mold casting factory？
Shell mold casting is a precision sand casting process that uses resin-coated sand to form thin, rigid shell molds with improved dimensional accuracy and surface finish compared to conventional sand casting. The process is particularly suitable for ferrous alloys with good castability and moderate pouring temperatures, where consistent quality, smooth surfaces, and higher production efficiency are required. Due to limitations in mold refractoriness and gas permeability, Simis shell molding is primarily applied to gray iron, ductile iron,Low-Alloy Cast Iron and selected carbon and low-alloy steels, typically for small to medium-sized components produced in medium to high volumes.
| Material Category | Why It Is Suitable for Shell Molding | Simis shell mold casting Foundry Typical Applications | Simis shell molding FoundryCommon Grades |
| Gray Iron | Excellent fluidity and low solidification shrinkage allow gray iron to fill thin shell molds reliably. The flake graphite structure reduces internal stress, while shell molds provide improved surface finish and dimensional consistency compared to green sand | Engine components, housings, brake parts, valve bodies, pump casings | ASTM A48 Class 30/35/40, EN-GJL-250, EN-GJL-300 |
| Alloy Cast Iron | Alloying elements (Cu, Ni, Cr, Mo, W) improve strength, wear resistance, and corrosion resistance. Shell molding provides better surface finish and dimensional accuracy than conventional sand casting. Low-alloy grades are easier to process, while high-alloy grades can be used for small to medium-sized parts, but require careful mold design and process control due to higher melting temperature, shrinkage, and gas sensitivity | Automotive structural parts, valve and pump bodies, machinery housings, wear-resistant liners, small high-performance components | Low-alloy Cast Iron: EN-GJL / EN-GJS; High-alloy Cast Iron: ASTM A532 Class I/II, Ni-Resist ASTM A439, EN-GJN-Ni series |
| Ductile Iron | Controlled spheroidization combined with improved mold rigidity enables shell molding to produce ductile iron components with stable nodularity and good surface quality. The process supports tighter tolerances than conventional sand casting for medium-sized, repeatable parts | Automotive components, bearing housings, brackets, hydraulic components | ASTM A536 65-45-12, EN-GJS-500-7 |
| Carbon Steel | For carbon steels with moderate pouring temperatures, shell molds provide adequate refractoriness and improved surface finish. Shell molding is suitable for relatively simple geometries where dimensional repeatability and reduced machining are required | Valve components, pipe fittings, flanges, mechanical parts | ASTM A216 WCB |
| Low-Alloy Steel | Selected low-alloy cast steels can be produced using shell molding when alloy content and part size are controlled. The rigid shell mold helps maintain dimensional accuracy, though careful gating and feeding are required to manage shrinkage | Valve bodies, brackets, machinery components | ASTM A217 WC6 (limited application) |
