Quantifying quality of 3D printed clay objects using a 3D structured light scanning system
Abstract Three dimensional (3D) printing, or additive manufacturing, has been increasingly used in many fields, including the medicine, food, sensing, metal, automotive, and construction industries. Regardless of its growing applications, there are few of methods, guidelines, and specifications for measuring and quantifying the qualities of 3D printed objects. This is particularly so for objects those are too small, too large, and/or too fragile to be handled manually. In this study, for the first time, a non contact, and non destructive measurement method, a 3D structured light scanning system (3D SLSS) was employed for evaluating the printing qualities of clay objects with different levels of visual defects (e.g. roughness and distortion) 3D scanned images of these clay samples were developed using 3D SLSS. Then, they were sliced along their sides (perpendicular to the base) to generate a number of two dimensional (2D) plots, from which various parameters (e.g. sample total height [Htotal] outer diameter [DMouter] layer thickness [TL] layer width, (WL] surface angle [Sa] semi cross sectional area [XA] and surface roughness [R] were measured. These measurements were then compared with the designed values. The percentages of the differences between the measured and designed values were used to develop a diagnosed area of deficiency, by which the overall qualities of the printed samples were quantified. The results illustrated that all the printed samples exhibited certain differences between their measured and designed values, even for those that appeared well printed. Compared with the designed object, the printed samples generally had reduced total height, diameter, and layer thickness; increased layer width; measurable distortion; and visible surface roughness. Many of these were largely because the freshly printed clay deformed under the weight of the layers above. The distortion angle and area are two necessary parameters for quantifying the degree of distortion of a printed sample. The diagnosed area of deficiency can well describe the overall qualities of the printed samples. 3D SLSS is a relatively simple, fast, and inexpensive characterization method. Moreover, it can be conveniently extended to various industries for quality control of diverse 3D printing products.