A systematic approach for an accuracy level using rapid prototyping technologies

Nowadays there has emerged a series of rapid prototyping processes with great potential, and designers and engineers need to know the accuracy performance of these processes to compare and select the best solution. There is a significant lack of published data related to rapid prototyping processes and feature accuracy. This research was conducted to minimize this gap and provide much needed accuracy in terms of dimensional and geometric information. The methodology includes the summarization of previous studies and definition of a benchmarking part that is composed of elementary shapes representative of different features most likely to be found in a final product. The benchmarking part was controlled in terms of dimensional accuracy, geometric precision and freeform deviation. The sources of errors controlled by the final user were analysed, like Standard Tessellation Language (STL) file format resolution and build direction. Four custom rapid prototyping processes have been used and compared: stereolithography, selective laser sintering, fused deposition modelling and three-dimensional printer. Computer numerically controlled machining has been used as an alternative prototyping process in this study as a standard to compare costs and accuracy. This work assessed measures that can be used to quantify the accuracy performance for a given part so that the choices for prototyping can be made based on scientific knowledge and best working practices. These results are very useful for designing products to be prototyped or manufactured through direct methods. The results can be used to improve the functionality of prototypes and the decision process through the best systematic approach.