Stereolithography build time estimation based on volumetric calculations

Abstract

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.

Ten challenges in 3D printing

“…Stereolithography, selective laser sintering, and similar technologies are limited by how fast the material in use reacts to the energy source. They also require the build platform be recoated with material after each layer is completed, requiring additional time [34]. Direct deposition processes, like fused deposition modeling, are limited by how quickly the material can be extruded from the print head.…”

A novel decision-making logic for hybrid manufacture of prismatic components based on existing parts

“…It is also somewhat restricted by the capability of the additive process. Due to the majority of engineering parts being prismatic or cylindrical (Campbell et al 2008), the iAtractive process is designed primarily for prismatic part production. However, the increasing customer demands lead to a paradigm shift, which stimulates and increases the needs for customised products with complex structures.…”

“…existing part with final features, with non-final features, and with both final and non-final features. As the iAtractive process is designed primarily for prismatic part manufacture and the majority of engineering parts are prismatic or cylindrical (Campbell et al 2008), this study is focused on prismatic part manufacture. Therefore, six types of features are considered, which are boss, pocket, hole, slot, step and planar face.…”

Transparency Built‐in

“…Commercially available rapid prototyping software packages contain build time estimation functionality (Campbell et al ), as do the machine software suites sold in bundles with additive systems (Ruffo et al ). Offering a framework for the classification of AM build time estimators, Di Angelo and Di Stefano () argue that the existing approaches can be divided into “detailed‐analysis” methods based on knowledge of the inner workings of AM systems and “parametric” methods informed by data on a set of process characteristics such as layer thickness, hatch distance, and laser scan velocity.…”

“…Build time estimation forms the starting point for AM production cost estimation models in the literature (Alexander et al ; Byun and Lee ; Campbell et al ; Ruffo et al ). Ignoring “ill‐structured costs” (Son ) arising from build failure, idleness, and inventory, Ruffo and colleagues () propose an AM costing model viewing the total cost of a build, C Build , as the sum of all direct raw material costs and the indirect costs (equation ).…”