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Development of non-contact methods for measuring the outside geometry of AM parts

Additive manufacturing is rapidly growing with more and more industries incorporating it in their manufacturing processes. However, before it can be widely adopted in the manufacturing industry, purpose built metrology systems must be designed to ensure tight tolerances and traceability are provided. The aim will be to develop an optical metrology system for measuring the complex outside form of AM parts.


Patrick Bointon


Prof Richard Leach


Metrology is an important tool for manufacturing as it provides the necessary feedback for process control and post-process troubleshooting. Without fast and accurate metrology, setting up production procedures and maintaining production tolerances to minimise scrap parts is not possible. Metrology is especially important in the field of additive manufacturing (AM), where, in order to scale up production, multiple machines are used on the same manufacturing floor.

Each machine can be considered as being an independent manufacturing process or manufacturing line that needs process feedback in order to achieve tight tolerances on the products being manufactured and allow comparability. In order to further the metrology measurement field and aid the continued progression of AM, a new and more flexible system needs to be developed. This is due to the limitations of current measurement systems, such as: lack of flexibility; struggle to cope with high slope angles, surface reflectivity problems and time of measurement vs performance/accuracy trade-off.

Based on current research trends and recent publications, optical methods (Coded Structured Light, CSL) show considerable promise and so the aim of the PhD will be to develop and utilise CSL techniques in a new system for measuring the complex geometries on additive manufactured parts. This will require optical instrument R&D and an investigation of existing commercial measurement systems currently in use.

Comparisons with contact techniques will be carried out. The new system will be aimed at being capable of measurement volumes of a cube of up to 750 mm sides to accuracies approaching 5 µm. A number of industrial case study components will be measured using the techniques to demonstrate their performance with different geometries, materials and surface textures.


Image source

“Structured-light 3D surface imaging: a tutorial”

Jason Geng - Maryland 20852, USA (

IEEE Intelligent Transportation System Society, 11001 Sugarbush Terrace, Rockville,

Published March 31, 2011 (Doc. ID 134160)

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