Accuracy of the New Method of Alignment of Workpiece Using Structural-Light 3D Scanner

Abstract

This paper presents a new method of aligning workpieces for machining by means of optical measurements followed by the results of verifi cation tests of this method. The overview of modern assessment methods of irregularly shaped blanks are discussed in this study, with particular emphasis on cast iron castings, as well as on problems related to their positioning and fi xing for machining. A fl owchart of the proposed method and its verifi cation results in industrial conditions are also presented. The essence of the method is based on the comparison of two spatial models: a designed workpiece model and the actual model of a casting produced with a coordinate measuring technique. A series of six iron castings were tested. The obtained results indicate that the errors caused by locating amounted to a maximum of 2 mm (average 0.5 mm) and were three times lower than actual machining allowances. This points to the correctness of the developed method and the great potential for its industrial application. Additionally, a method for improving locating accuracy by modifying the shape of the retaining pin is presented.

Study of shape and dimensional accuracy in the production of ductile iron castings using 3D scanning

“…However, the work of the authors [10] is closest to the present contribution. Attention is focused on implementing 3D measurement and scanning methods during the preparation of a casting for machining, which is closely related to the output dimensional and quality control of castings in a cast iron foundry.…”

Guidelines for Accurate Multi-Temporal Model Registration of 3D Scanned Objects

“…In recent decades, there have been rapid advancements in the field of three-dimensional (3D) scanning, with applications in product inspection, reverse engineering, medical research, archeology, and construction of urban environment scenes [ 1 , 2 , 3 , 4 , 5 , 6 ]. Data collected from 3D scanners are used to generate 3D model reconstructions of an object of interest that can be used to evaluate geometric or dimensional object quality [ 4 , 7 ] and to quantify morphological changes [ 8 ], including mechanical wear in biomaterials [ 9 , 10 , 11 ].…”

“…Maximum overlap aligns two 3D models by finding the optimal transformation between features on a reference and target 3D model and is most commonly achieved through Iterative Closest Point (ICP) algorithms [ 7 , 13 ] or variants of ICP [ 14 , 15 ]. These algorithms are generally applied to the entire 3D model geometry, such as when analyzing tolerances in quality part inspection [ 2 ]. However, there are drawbacks to selecting the entire 3D model geometry when detecting changes in localized morphology at multiple timepoints (e.g., mechanical wear and degradation), since these changes can create natural variations between the reference and target 3D models that can skew the mapping functions and cause registration errors [ 8 ].…”

Combining the Technology of Long-Range Laser 3D Scanners and Structured Light Handheld 3D Scanners to Digitize Large-sized Objects

“…Among others, they are applied by reverse engineering [1]. We have been also noticing some attempts to use them in the precise positioning of complex-shaped objects in the working space of a machine tool or welding machine to improve or automate the process [2,3,4]. 3D scanners may also be used to measure people, for instance for medical purposes [5,6].…”