Reverse engineering for additive manufacturing

Abstract

Additive manufacturing is dependent on three-dimensional (3D) data to produce and inspect parts fabricated by the additive manufacturing process. Reverse engineering provides methods to generate the required 3D data. 3D data is generated by making a series of measurements and reducing that information into a 3D model of some nature. In the simplest form, a scale and a computer-aided design (CAD) software program can be used to measure features and then reproduce them as a 3D CAD model. However, many objects are very complex and would require a significant number of measurements and interpretations to produce a well-defined 3D model. Manual measurement of complex items can result in inconsistent results from part to part or operator to operator. So, a more robust and repeatable method to measure parts is desirable. Metrology is the science of measurement, defined by the International Bureau of Measures as “the science of measurement, embracing both experimental and theoretical determinations at any level of uncertainty in any field of science and technolgoy” (What is metrology? BIPM. Retrieved 01 Dec 2011. (2004)). The manufacturing industry uses the term “metrology” to describe the generic group of devices used to make measurements. There is a wide array of metrology devices and associated software to support both reverse engineering and inspection of parts. Metrology devices are selected based on the application requirements, like desired data accuracy, data density, contact measurements verses noncontact measurements, part size, part surface properties, and part access. Likewise, reverse engineering software is selected based on the application needs, like operator skills and the level of automation desired. This chapter will provide insight into fundamental considerations for metrology and software to support both inspection and reverse engineering of additive manufactured parts.