Optimisation of Additive Manufactured Sand Printed Mould Material for Aluminium Castings

The foundry industry provides near net shape metal casting for a wide range of industries, producing components in ferrous and non-ferrous metal castings in a range of sizes from miniature items as small as zips to large castings such as ships' propellers. The sand casting process has changed little over centuries, except for incremental improvement in materials and mechanisation of the process, the fundamental process being that of sand compacted around a pre-manufactured mould pattern which is then removed to cast the metal. For mass production stage this is both efficient and economical, however during development and prototyping production stages the requirement for mould production tooling, the design constrained production method means this stage is often a major bottleneck in new product development. Additive manufacturing has been used to manufacture sand moulds for metal sand casting using laser sintering and sand bonding process without the need for tooling. This research focuses on optimisation of the build parameters for additive manufactured sand print bonded mould tools specifically for automotive aluminium castings. The approach taken in this research is to evaluate characteristics of casting produced and relates to the permeability, dimensional accuracy, tensile and compressive crush strength, density, impact strength and high temperature resistance of the mould tool produced. These properties are required to compare the 3D Sand Printing (3DSP) process to traditional Furan based casting sand mixtures. The automotive turbo charger casing was used to validate the build parameters optimisation process. This research would be of interest to designers and manufacturing engineers wishing to take advantage of the implications of having new design freedom, tool-less manufacturing with short lead times in a wide range of materials using fundamentally tried and tested foundry industry casting techniques. This research has demonstrated 3DSP process has the capability to manufacture sand patterns to permeability, accuracy, tensile and compressive strength comparable to traditional sand casting process.