<p>From what I understand, UV curing of resin prints works by starting a chemical reaction that hardens the resin permanently.</p>

<p>Also, a curing step after print is needed to speed up the print and also to reduce the curing during print, which would cure resin beyond the current layer.</p>

<p>However, what is the transmissivity of UV light in partially cured prints? If I print a more massive object, or if I use an opaque resin, how deep will the object harden properly? Absorption is always exponential, meaning that it decreases quickly with depth.</p>

<p>Depending on the resin, how thick prints can be effectively cured? This information is not provided with the resin, which I actually would expect from reputable manufacturers.</p>

[{'answer_id': 13657, 'author': 'R.. GitHub STOP HELPING ICE', 'author_id': 11157, 'author_profile': 'https://3dprinting.stackexchange.com/users/11157', 'pm_score': 0, 'selected': False, 'text': '<p>In terms of Cura\'s model for showing overhangs, I\'m nearly sure it\'s just the ratio - rise over run, or rather run over rise. And indeed that\'s what makes sense mathematically:</p>\n\n<p>At least some portion of the wall extrusion in layer N+1 needs to sit on top of the corresponding wall extrusion in layer N. For a given 3D surface slope, the "run" - the distance the cross-section moves from one layer to the next, which needs to be bounded by some fraction of the line width - varies proportionally to the "rise" - the layer height.</p>\n'}, {'answer_id': 13659, 'author': 'FarO', 'author_id': 2338, 'author_profile': 'https://3dprinting.stackexchange.com/users/2338', 'pm_score': 1, 'selected': False, 'text': "<p>A wide line works if there is something below it to squeeze the filament against, but if you don't have a full layer below it, it will stay thinner and it will droop. I would not use extreme ratios on overhangs. Still, do a parametric test: a overhang tower (a compact one) at different line widths and layer heights. If you test 3 layer heights and 3 line widths, it's only 9 short prints.</p>\n<p>However, as you can see in filament reviews, different materials behave differently. I think there is no <em>a priori</em> optimal value.</p>\n"}, {'answer_id': 13875, 'author': 'woneill1701', 'author_id': 21453, 'author_profile': 'https://3dprinting.stackexchange.com/users/21453', 'pm_score': 1, 'selected': False, 'text': '<p>Cura high-lights overhangs in red if the printer would end up printing completely into thin air. </p>\n\n<p>If your overhang is angled instead of being a purely vertical-to-horizontal transition, a much thinner layer height can increase the chances that enough of the prior layer exists to support the next layer being printed. </p>\n\n<p>Basically, the thinner the layer (within reason), the greater the allowable angle of overhang that is safe to print.</p>\n'}]
['https://3dprinting.stackexchange.com/questions/13660', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/2338/']