Method and apparatus for separation of cured resin layer from resin support in additive manufacturing

An additive manufacturing apparatus configured to produce a component layer by layer, the apparatus comprising:

• a support structure;
• a stage positioned opposite the support structure and configured to hold a stacked arrangement of one or more cured layers of a resin;
• one or more actuators operable to move the stage away from the support structure;
• a radiant energy apparatus positioned opposite the stage such that the support structure is positioned between the radiant energy apparatus and the stage;
• a foil that extends between the support structure and the stage;
• a material depositor operable to deposit the resin that is curable onto a build surface that is defined by the foil and positioned such that it faces the stage;
• the radiant energy apparatus being operable to generate and project radiant energy through the support structure and the foil on the resin in a predetermined pattern;
• a foil separation device that is positioned between the stage and the support structure;
• and
• wherein the foil separation device includes a first holddown device and a second holddown device that are configured such that a remaining structure contacts the first holddown device and the second holddown device when the stage is moved away from the support structure, the first holddown device and the second holddown device are positioned a distance from the support structure, the distance being greater than a thickness of the foil and the cured layer.

A method of operating an additive manufacturing apparatus that includes a stage, a support structure, a foil that extends between the stage and the support structure and that defines a build surface, a resin handling assembly, and a foil separation device, the method comprising the steps of:

• performing an additive manufacturing cycle including the following steps:
• depositing an uncured layer of resin onto the build surface such that it defines a resin surface;
• moving the stage such that a working surface contacts the resin surface;
• curing at least a portion of the uncured layer of resin to create a newly cured layer;
• moving the stage and thus, the newly cured layer, away from the support structure;
• and
• operating the foil separation device to separate the newly cured layer from the build surface,
• wherein the foil separation device includes a first holddown device and a second holddown device that are configured such that a remaining structure contacts the first holddown device and the second holddown device when the stage is moved away from the support structure, the first holddown device and the second holddown device are positioned a distance from the support structure, the distance being greater than a thickness of the foil and the cured layer.