Fig. 4.

Schematic of “cupping” damage during the printing of a hollow, cup-like feature. (A) During printing, a UV light source (LED) forms a new crosslinked layer of resin flush against the teflon sheet. This design is an inverted bowl shape; supports are not shown for clarity. (B) After a layer is finished printing, the print is peeled away from the teflon sheet, e.g. by pulling the vat down and/or the baseplate up. This process creates a region of suction within the hollow cup feature; the surrounding pressure, now higher than the pressure within piece, may form a stress fracture on the print.