Stereolithography build time estimation based on volumetric calculations

Purpose - Not all the inventors and designers have access to computer-aided design (CAD) software to transform their design or invention into a 3D solid model. Therefore, they cannot submit an STL file to a rapid prototyping (RP) service bureau for a quotation but perhaps only a 2D sketch or drawing. This paper proposes an alternative approach to build time estimation that will enable cost quotations to be issued before 3D CAD has been used. Design/methodology/approach - The study presents a method of calculating build time estimations within a target error limit of 10 per cent of the actual build time of a prototype. This is achieved by using basic volumetric shapes, such as cylinders and cones, added together to represent the model in the 2D sketch. By using this information the build time of the product is then calculated with the aid of models created in a mathematical solving software package. Findings - The development of the build time estimator and its application to several build platforms are described together with an analysis of its performance in comparison with the benchmark software. The estimator was found to meet its target 10 per cent error limit in 80 per cent of the stereolithography builds that were analysed. Research limitations/implications - The estimator method was not able to handle multi-component complex parts builds in a timely manner. There is a trade-off between accuracy and processing time. Practical implications - The output from the estimator can be fed directly into cost quotations to be sent to RP bureau customers at a very early stage in the design process. Originality/value - Unlike all the other build estimators that were encountered, this method works directly from a 2D sketch or drawing rather than a 3D CAD file.