Vacuum Assisted Casting of Aluminum 6060 Alloy using Rapid Prototyping Pattern

Abstract

The manufacturing of parts in aerospace and medical industries is most critical where materials of the part plays important role. The material composition of part decides the performance of part during the operation. The casting process is the only manufacturing process where innovative parts having non-linear geometries can be manufactured using rapid prototyping (RP) pattern. The CAD part can be directly converted into pattern (physical part) without human intervention and tooling using rapid prototyping and the design engineer is free from constraint from manufacturing. In this paper, the manufacturing of orthopedic implant using casting process is discussed where pattern is fabricated using rapid prototyping. Use of simulation software in casting viz. AutoCAST makes the otherwise complex process of casting much simpler and efficient. The medical implants are manufactured using the biocompatible metals like SS 316L, Co- Cr alloy. The Titanium is most preferred metals in medical implants as it is more biocompatible than SS 316 L and Co- Cr Alloy. The stress shielding effect is also not observed in Titanium made implant because of low modulus of elasticity compared to SS 316L and Co-Cr alloy. One of the major issues in the casting of medical implant is oxidation of metal during melting and pouring. The vacuum assisted casting is the only solution while using casting as the process of manufacturing for medical implant. The authors of the paper carried out the casting of part using vacuum for aluminum alloy 6060. The work will be further extended to biocompatible metals. The in-house induction furnace, having capacity of 5 kg is modified for meting and pouring unit in vacuum. The 500 LPM double stage direct drive rotary high vacuum pump is used for creating vacuum. The bottom pouring arrangement is used for pouring the molten metal in mould. The trial is successfully carried out for casting the part with and without vacuum. The result of as cast part using vacuum is very much promising compared to as cast part without vacuum. The biocompatible materials will be used for casting with vacuum which will help in designing the patient specific medical implants.