Curing characteristics of acrylic photopolymer used in stereolithography process

Abstract

Rapid prototypes formed using stereolithography (SL) method have to undergo post‐curing to increase their strength and rigidity. This study attempts to reduce, if not eliminate, post‐cure distortion by characterising curing behaviours. Curing (both heat and UV initiated) characteristics of an acrylic‐based photopolymer under actual fabrication conditions were studied using Raman spectroscopy as well as differential scanning calorimetry (DSC) and differential scanning photo‐calorimetry (DSP). Specimens of single photopolymer lines were created using a SL machine. Raman spectroscopy was used to quantify the curing percentage at different areas on the cross‐section of these lines. Curing percentages before and after post‐curing were also obtained from the experiments. Difference in percentage of post‐curing gave an indication of the distortions faced. It was found that uncured and partially cured resins trapped within the photopolymer resulted in inhomogeneity of curing in the specimens causing shrinkage and distortion.

3D printing method of multi piezo head using a photopolymer resin

“…In practical fabrication, if the average exposure is below Ec, no resin is cured, otherwise if the average exposure falls into the range Ec<Eav<2Ec, the resulting prototypes have not sufficient mechanical strength [3,4]. Fig.…”

Composite rapid prototyping: overcoming the drawback of poor mechanical properties

“…These inaccuracies are further magnified during the post-curing stage. During the last few years, an overwhelming amount of research has been carried out to understand and to improve both the process and the photopolymer [7][8][9][10][11][12][13][14][15]. All these have been carried out with an aim of achieving prototypes of higher accuracy.…”

Over-Curing Reduction of Parts Fabricated by the Solid Laser-Diode Plotter Rapid Prototyping System using the Taguchi Method

“…More than half of the RP systems in the world are stereolithography machines. Most of the research concentrates on stereolithography because of its publicity [1][2][3][4]. The capital cost of a stereolithography machine is very high because of the high-power laser and the associated control devices [5].…”