Development of precision spray forming for rapid tooling

The aim of the work is to improve the capability of the precision spray forming (PSF) rapid tooling process so that it can be extended to various applications. This work comprises the upgrading of the current spray-forming machine from single atomizer to twin atomizers, so that the capability is much improved in terms of insert size and complexity. As a result, the insert size is increased from about 200 mm to 400 mm in diameter, and the process is more reliable to make complex structures. Know-how is accumulated for making large and/or complex inserts with controllable surface and internal soundness. A process of spray forming conformal cooling channels in die inserts or other components used at elevated temperatures is also developed and various mould inserts are spray formed. In this paper the plant modification is described. It is shown that the twin atomizers are more reliable in spray forming small inserts of about 200 mm in diameter and of high complexity than the single atomizer system. Spray forming of disc type inserts up to 400 mm diameter is demonstrated. Influence of deposition temperature and substrate moving speed, as well as the treatment of the ceramic mould surface is determined and the technical measures to prevent surface defects related to large insert spray forming are specified.