SBIR Phase I: Development of a Metal Aggregate Rapid Tooling Process for Casting Aluminum Alloys

该小型企业创新第一阶段研究项目旨在开发一种新型快速模具材料，用于低成本生产小批量和原型铸件。这种快速模具材料提供了容易的造型典型的砂造型，但在性质和性能的金属永久模具。模具包括具有硅酸盐粘合剂的金属骨料，热处理以实现适当的硬度和尺寸稳定性。该项目将解决以下问题：（1）复杂模具的制造;（2）模具材料的特性;（3）分析用该模具生产的铸件的尺寸精度和表面粗糙度;（4）确定铝铸件在模具中凝固期间的冷却速率;（5）评估模具的耐热疲劳性和耐久性;（6）评估模具的寿命。（6）用这种方法制造快速模具的交货时间的确定;在这些模具中制造的铸件预计冷却得更快，从而导致更高的极限强度、延展性和延伸率。此外，由于更细的枝晶臂间距，预期在热处理期间更短的均匀化时间。这些特性使这种材料不仅对快速模具有吸引力，而且对砂型铸造中的轮廓冷铁也有吸引力。这些将被用来增加局部提取的热量从凝固铝，从而提高机械性能的关键部分的casting.The更广泛的（商业）的影响，从这个项目将是一个金属集料模具技术，适合自己的快速和廉价的成型模具原型开发铸件。该模具在金属型铸造工艺中具有潜在的应用，如重力永久型、低压压铸和注射成型塑料部件。金属骨料最明显的商业应用是在小体积、高强度铝铸件的模具中。作为永久性模具，金属骨料模具提供整体通风，无需机械制造通风孔，从而节省时间和成本。金属聚集体材料的另一个潜在应用是制造用于砂型铸造的成形冷铁。作为可模制材料，金属聚集体适合图案以形成导热模具，否则不容易实现。该公司的主要产品是铝叶轮的过程中，利用永久和砂模的组合。在铸造过程中被永久型捕获的型芯气体是产生缺陷的主要原因，导致废品率超过5%。耐用、可渗透的工具可以大大降低工具成本，从而更快地实现叶轮创新，从而实现更节能的制冷设计。

This Small Business Innovation Phase I Research project aims to develop a novel rapid tooling material for inexpensive production of low volume and prototype castings. This rapid tooling material offers the ease of molding typical to sand molding yet is comparable in properties and performance to metallic permanent molds. The mold comprises a metallic aggregate with a silicate binder, thermally processed to achieve appropriate hardness and dimensional stability. The project will address the following: (1) manufacturing of a complex mold; (2) characterization of the mold material; (3) analysis of the dimensional accuracy and surface roughness of castings produced with this mold; (4) determination of the cooling rates during solidification of aluminum cast in the mold; (5) evaluation of the thermal fatigue resistance and durability of the mold; (6) determination of the lead time to fabricate rapid tooling by this method; Castings made in these molds are expected to cool faster resulting in higher ultimate strength, ductility and elongation. In addition, because of the finer dendrite arm spacing, a shorter homogenization time during heat-treating is anticipated. These attributes make this material attractive not only for rapid tooling but also for contoured chills in sand casting. These would be used to increase local extraction of heat from solidifying aluminum, thereby improving mechanical properties in critical sections of the casting.The broader (commercial) impact from this project would be a metallic aggregate mold technique that lends itself to rapid and inexpensive forming of molds for prototype development castings. The mold so produced has potential applications in metal mold casting processes such as gravity permanent mold, low pressure and die-casting and injection molded plastic parts. The most apparent commercial application for the metal aggregate is in molds for low volume, high strength aluminum castings. Used as a permanent mold the metal aggregate mold provides integral venting, eliminating the need for mechanically created vents thus saving time and cost. Another potential application of the metal aggregate material is in manufacturing of shaped chills for sand casting. As a moldable material the metal aggregate fits the pattern to form a thermally conductive mold otherwise not readily achievable. The company's principal product is aluminum impellers made by a process, which utilizes a combination of permanent and sand molds. Core gases trapped by the permanent mold during the casting process are a major cause of defects, resulting in scrap rates in excess of five percent. A durable, permeable tool could substantially reduce that tooling cost, leading to more rapid implementation of impeller innovations, hence more energy efficient refrigeration designs.