Stereolithography cure modelling and simulation

In situ monitoring of mechanical properties during photopolymerization with particle tracking microrheology

“…Beer's law predicts the exponential decay of the amount of photons delivered to the sample with increasing thickness of the absorbing medium, thus limiting the initiation reactions of free-radical photopolymerization at greater penetration depth. For E4PETeA, at 5.0 wt% DMPA 63% of the light penetrates to the bottom of a 100 mm thick sample [4], while at 0.25 wt% almost 100% of the incident light reaches the bottom; nevertheless, the gelation variations for the 0.25 wt% samples are significant.…”

“…Current techniques are apparently not sensitive enough to accurately determine all rate constants in the reaction pathway, as is shown by the discrepancies between experimental results and model predictions. Although the parameters used in the acrylate photopolymerization model have previously been shown to provide reasonable agreement with the differential photocalorimetry (DPC) and stereolithography part shape measurements [4], the more stringent comparison with microrheology data over a wide range of initiator concentrations reveals the limitations of this model. Studies are currently underway to understand which model parameters may be relatively insensitive to the methods currently used to parameterize the photopolymerization model and which can be better estimated by additional fitting of the model to the microrheology data.…”

“…Studies are currently underway to understand which model parameters may be relatively insensitive to the methods currently used to parameterize the photopolymerization model and which can be better estimated by additional fitting of the model to the microrheology data. Work is also in progress as mentioned previously to model the effect of oxygen quenching observed experimentally in the microrheology experiments by parameterizing the quenching mechanisms in the existing radical photopolymerization model [4].…”

“…In the case of SL, there is significant interest in developing processes and materials that result in higher throughput, better spatial resolution, and improved surface finishes. Making such improvements would be greatly aided by quantitatively accurate models that can capture the behavior of photopolymer resins during polymerization, and during the last decade several research groups have made significant strides forward [1][2][3][4][5][6][7][8]. One of the main problems with model development is the need for experimental validation and refinement, which is still problematic with existing techniques.…”

Resource-Efficient Process Chains to Manufacture Patient-Specific Prosthetic Fingers

“…The recoating blade then deposits a new layer of resin to be solidified. The layers bond together and this process is repeated until the part is complete as stated by Jacobs [19], and Tang [20].…”