壳模, also referred to commonly as shell molding, is comparatively a new casting technique, developed in Germany in the 1940s.
It’s a type of metal casting process that involves pouring molten metal(ferrous or non-ferrous) or alloy into sand and resin which is further heated and shaped to build a mold.
Shell mold casting offers improved surface finish and higher precision compared to other metal casting methods, and suitable for small parts that require complex shapes and high dimensional accuracy.
Shell mold casting is applied to various industries such as aerospace, 医疗的, 和汽车工业.
It is especially popular in the automotive industry and is often employed to manufacture camshafts, 变速箱, 曲轴, 气缸盖, bearing housings, lever arms, and valve bodies.
Two matching metal pattern halves—typically machined from steel or iron—are produced to the exact geometry of the desired casting (plus allowances for shrinkage and shell thickness).
Each pattern half is heated (≈180–250 °C), lightly sprayed with a release agent, then dipped into a “dump box” containing fine sand coated in a thermosetting resin.
The hot pattern cures a uniform shell layer (6–12 mm thick) as excess sand is shaken off.
The two cured shell halves are carefully stripped from their patterns.
If internal cavities are required, resin‐bonded sand cores are placed inside one shell half.
The cope (top) and drag (bottom) shells are then clamped together in a flask, and the gating system (浇道, 跑步者, vents) is attached.
Molten metal or alloy (例如, 铁, 钢, 铝) is heated to its liquidus temperature and poured by gravity into the sprue.
The metal fills the shell cavity, replicating fine details and thin sections.
The thin, ceramic‐like shell conducts heat away rapidly.
After an appropriate cooling interval—often just a few minutes at ambient temperature—the metal has solidified into a robust casting.
The flask is opened and the shell fragments are broken away to free the casting.
The part is then freed of any gating or core material and undergoes any required trimming, 磨削, or surface finishing before inspection.
Shell molding accommodates most ferrous and non-ferrous alloys, 例如:
| Alloy Family | 典型的成绩 | Key Properties & Applications |
|---|---|---|
| Gray Iron | ASTM A48 Class 20–40 | Excellent machinability & vibration damping; used for engine blocks, 外壳. |
| 球墨铸铁 | ASTM A536 60-40-18, 65-45-12 | Higher strength & toughness than gray iron; ideal for gears, 曲轴, 阀门. |
| 碳钢 | 美国钢铁协会 1018, 1020, 1045 | Good strength and weldability; used for shafts, 括号, 结构件. |
| 合金钢 | 4140, 4340, H13 | Enhanced hardness, 韧性, 和耐磨性; used in dies, 工装, 重型机械. |
| 不锈钢 | 304, 316, 17-4PH值, 2205 (复式) | Corrosion resistance and strength; used in chemical, 食物, 医疗的, and marine parts. |
| 铝合金 | A356, A357, ADC12 | 轻的, good fluidity; used for automotive brackets, 外壳, aerospace fittings. |
| 铜合金 | C905 (锡青铜), C836 (铝青铜), C230 (Cartridge Brass) | Excellent wear and corrosion resistance; 用于轴承, 衬套, 船用五金件. |
| 镍基合金 | 铬镍铁合金 625, Hastelloy C276 | Outstanding high-temperature strength and corrosion resistance; used in aero-engines, 化学加工. |
| 镁合金 | AZ91D, AM60 | 非常轻巧; used in electronics housings and automotive components. |
| 锌合金 | 负载 3, 负载 5 | Low melting point and excellent detail reproduction; used for small, 复杂的零件 (hardware, 配件). |
1. Proprietary Resin‐Sand Formulations
2. High-Speed, Automated Shell Production
3. Expert Pattern & Tooling Design
4. Broad Alloy Capability
5. Tight Dimensional Control
6. Lean, Green Operations
7. Comprehensive Quality Assurance
8. Dedicated Technical Support
| 行业 | Typical Shell Mold Castings | Typical Products |
|---|---|---|
| 汽车 | Camshaft and crankshaft housings, gearbox and transmission cases, 气缸盖, bearing carriers, and linkage arms—benefit from tight tolerances and fine surface finish, reducing or eliminating post-machining. |  |
| Aerospace & Defense | Actuator brackets, fuel-system fittings, small turbine stator segments, control-surface hinges, and structural brackets—leveraging weight-sensitive, high-precision parts where repeatability and fatigue resistance are critical. |  |
| 医疗设备 | Surgical instrument handles and housings, implant-fixture bushings, orthopedic bracketry, and fluid-control valves—requiring complex internal passages, biocompatible alloys, and sterilizable finishes. |  |
| Industrial Valves & Pumps | Precision valve bodies, 叶轮, volutes, and pump housings cast in stainless or duplex stainless steels—resisting corrosive media while maintaining exacting dimensional requirements for reliable sealing and flow control. |  |
| Oil & Gas / 石油化工 | Chemical-service fittings, filter housings, manifold blocks, and instrumentation flanges—taking advantage of exotic alloys (例如, 铬镍铁合金, 哈氏合金) with minimal surface porosity and high dimensional fidelity. |  |
| Consumer & Decorative | Ornamental door handles, 照明灯具, sculpture components, and architectural accents—shell-cast in brass, 青铜, or aluminum to capture fine textures and crisp edges. |  |
| Renewable Energy & Power Generation | Small hydraulic turbine nozzles, control-valve bodies, and generator accessory brackets—benefiting from rapid turnaround and the ability to cast heat-resistant alloys with tight wall-thickness control. |  |
| Same side of parting line: | ± .020 for 1st 3″ | Add ± .003 / inch over 3″ |
| Across parting line: | ± .030 for 1st 3″ | ± .003 / inch over 3″ |
| Draft: | Typically 1° | Certain applications at 0° draft. |
| Typical Finish Stock: | .060″ maximum | |
| Hole size cast into part: | DIAMETER | DEPTH |
| Less than 0.5″ | Equal to diameter | |
| 0.5″ – 1.0″ | Equal to 1.5 times diameter | |
| Greater than 1.0″ | Equal to 2 times diameter |
Shell mold casting is a precision sand-based process in which a heated metal pattern is coated with fine, resin-bonded sand to form thin “shell” halves. Once cured and assembled, these shells serve as the mold into which molten metal is poured.
Almost any alloy is suitable—including gray and ductile irons, carbon and alloy steels, 不锈钢, 铝合金, copper-based alloys, and even nickel-based superalloys—thanks to the shell’s heat resistance.
Typical dimensional tolerances reach ±0.3 mm per 100 毫米, and surface finishes are in the Ra 3–6 µm range. This precision often eliminates or minimizes secondary machining.
Shell molding excels at small to medium components (from a few grams up to about 50 公斤). Shell halves larger than this become difficult to handle and may crack under their own weight.
Each shell half cures in roughly 10–30 seconds on automated dip-and-shake equipment. This quick turnaround supports fast prototyping and moderate production volumes.
Intricate details—thin walls (down to 1.5 毫米), 底切, fine ribs, and internal passages—are readily achieved. Cores can be inserted for complex internal cavities.
Select shell molding when your parts require small- to medium-size, 高维精度, fine surface quality, and complex detail.
| 标准 | 砂型铸造 | 壳型铸造 | 熔模铸造 |
|---|---|---|---|
| 模具材质 | 绿沙 (二氧化硅 + 黏土) | 树脂键入的细砂壳 | 陶瓷外壳 (浸入浆料的蜡图案) |
| 模具成本 | 非常低 | 缓和 (加热图案 + 树脂砂) | 高的 (蜡工具 + 多个外壳倾角) |
| 霉菌再利用 | 不 (沙子破碎, 但是沙子是可以回收的) | 不 (每个外壳一次性, 沙子可回收) | 不 (每个陶瓷外壳一次性) |
| 零件尺寸范围 | 很小至很大 (> 几吨) | 小到中等 (最多约50公斤) | 非常小至小 (通常 < 10 公斤) |
| 尺寸公差 | ± 0.5 毫米 100 毫米 | ±0.25–0.35毫米 100 毫米 | ±0.15–0.25毫米 100 毫米 |
| 表面处理 (拉) | 6–12 µm | 3–6 µm | 1–2 µm |
| 壁厚 | ≥ 6 毫米 | ≥1.5–2毫米 | ≥ 1 毫米 |
| 复杂 & 细节 | 缓和 (内部功能所需的核心) | 高的 (薄壁, 很容易实现的精美功能) | 非常高 (底切, 复杂的几何形状) |
| 周期 | 慢的 (模具准备, 摇晃) | 快速地 (贝壳在几秒钟内固化) | 最慢 (多涂层和脱水步骤) |
| 产量 | 低到中 | 低到中 | 低到中 (100–1,000零件) |
| 典型的合金 | 铁, 钢, 铝, 青铜, ETC. | 铁, 钢, 防锈的, 铝, 铜合金 | 防锈的, 超级合金, 青铜, 铝 |
| 后处理需求 | 通常加工和表面清理 | 最小加工; 光完成 | 最小加工; 通常准备最终形状 |
| 最好的 | 大的, 重的, 成本敏感零件 | 精密小/中零件中等量 | 极其复杂, 薄壁, 高准确零件 |
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