The feel of 3D prints

Abstract

Since the expiration of the FDM printing patent by Stratasys in 2009, Fused Deposition Modeling(FDM) printing has taken a large step towards accessible consumer 3D printing. Also, more knowledge is sought in the process of FDM printing and optimizing quality as the layer by layer deposition inevitable results in poor surface quality. This study covered the surface quality of FDM printing by both objective and perceptual exploration. In the objective investigation the influence of build plate orientation, layer height, printing temperature, printing speed, cooling fans, angle orientation from horizontal plane, line width, material type and material color have been assessed with samples produced by the Ultimaker 3 3D printer. With an optical scanner build internally by Ultimaker, the surface roughness was calculated and statistically processed. Via screening and correlation experiments it was found that layer height and angle orientation from horizontal plane were most significantly influencing the surface roughness for both upward and downward facing surfaces. Other investigated parameters were found insignificant. The optical non-contact type of measurement has been compared with contact type measurement in a control experiment. For this the same trends in roughness values were visible for both types of measurements however contact type measurements resulted in lower surface roughness values.
The perceptual exploration of the study investigated the Point of Subjective Equality(PSE) and Just Noticeable Difference(JND) for the most significant surface roughness influencing parameters from the objective investigation. This experiment was done with the use of a new designed haptic apparatus. Participants of this experiment were capable to distinguish samples from each other in terms of different roughness values and detect small changes in fine-textures.
Combining the objective and perception data has led to a design of a 3D printable model which is an attempt in standardizing surface roughness in FDM printing. Inspired by currently available industrial surface roughness comparators, this design gives users of FDM printing the ability to explore and learn more about the topic of surface quality.