Apparatus for powder bed fusion

An apparatus for powder bed fusion, the apparatus comprising:

• a wall that defines a shaft;
• a powder platform configured to support a powder bed within the shaft and configured to move through the shaft, the powder platform comprising:
• a body;
• a first member that extends toward the wall and away from the body;
• and
• a second member that extends toward the wall and away from the body, wherein the body, the first member, and the second member form a cavity;
• and
• a sealing device that is in a compressed state from an outer perimeter of the sealing device to an inner perimeter of the sealing device such that the outer perimeter contacts the wall and the inner perimeter contacts the powder platform to form a seal between the powder platform and the wall, wherein the sealing device is positioned within the cavity,
• wherein the sealing device comprises:
• a first arm that contacts the first member and is positioned within the cavity;
• a second arm that contacts the wall;
• and
• a base that joins the first arm and the second arm and contacts the second member,
• wherein a portion of the powder bed that is between the first arm and the second arm applies a first force directed toward the powder platform against the first arm and a second force directed toward the wall against the second arm.