Study of SLA Printing Parameters Affecting the Dimensional Accuracy of the Pattern and Casting in Rapid Investment Casting

Abstract

Dimensional accuracy and geometric characteristics of the manufactured parts bear significant importance in product assembly. In Rapid Investment Casting, these characteristics can be affected by the printing parameters of the Additive Manufacturing method used in the pattern production process. Stereolithography is one of the important AM techniques mostly exploited in RIC due to its accuracy, smooth surface, and precision. However, the effect of SLA printing parameters on the dimensional accuracy and geometric characteristics have not been studied thoroughly. This study considers an experimental approach to study the effect of SLA printing parameters such as layer thickness, build angle, support structure density, and support touchpoint size on the dimensional accuracy and geometrical characteristics of the Castable Wax printed patterns and the Al cast parts. Taguchi’s Design of Experiment was used to define the number of experimental runs. SolidCast simulation was used to design the orientation of casting feeder to achieve directional solidification. Coordinate Measuring Machine measurements of deviations in the printed and cast parts were analyzed using the “Smaller-the-better” scheme in the two-step optimization method of Taguchi experiments. Build angle and Layer thickness were identified to be the first and the second most impactful parameters, respectively, affecting both the dimensional and geometric accuracy of Castable Wax patterns and Al cast parts, with optimal values of 0 deg and 0.25 μm, respectively. Both printed and cast parts had twice as many deviations in geometry as in dimensions. The sphere roundness and angularity were found to be the most and least accurate geometric characteristics, respectively. The dimensions in the Z direction were more accurate than in the X-Y directions, showing the smallest size deviations for height measurements and large deviations in the length, width, and diameter of the hole.

Recent Developments in Additive Manufacturing of Conductive Polymer Composites

“…[26] Other methods working with photosensitive resins are digital light processing (DLP), liquid crystal display (LCD), multijet printing (MJP), two-photon polymerization (2TPP), continuous liquid interface production (CLIP), etc., using different strategies to illuminate the liquid resin at defined positions. [27] Although these photopolymerization methods can usually create much finer structures than FDM, especially in case of 2TPP, they nevertheless may have problems with dimensional accuracy [28,29] and aging. [30,31] Powder-bed methods can work with polymers, metals, or even polymer/metal hybrid objects.…”

Tolerance analysis and design optimization of additively manufactured mechanical structure for a Raman spectrometer system

“…It is important to note that geometric properties of the measured specimen model may result in significant distortions and printing errors in the z-direction. In contrast to the test geometry used in this paper, Badanova et al 19 and Singh et al 20 propose different sample geometries with which they measure. Therefore, the deviation range in the z direction is determined according to the measurement results of Badanova and Singh, where the sample size is between 2.5 mm and 7 mm.…”

Uniform and graded bio-inspired gyroid lattice: Effects of post-curing and print orientation on mechanical property

“…These machine parameters can be maintained using slicer software. According to previous literature, average-to-high laser exposure time gives better polymerization, resulting in a better finish surfac, 46 and the default exposure time in the Chitubox software 1.8.1 is 6 s. However, a 7 s exposure time has been selected for better printing and overcoming the raft issue on the build plate. It is recommended to raise the bottom exposure time by 8 to 12 times compared to the standard layer cure time.…”