Sheet substrate retention device for securing a sheet substrate to a vacuum platen in an additive manufacturing system

A method of forming a 3D part using an extrusion-based additive manufacturing system, the method comprising:

• retaining a sheet substrate on a support surface of a vacuum platen using a retention device, the retention device comprising:
• a first frame portion having first and second opposing ends;
• a second frame portion extending substantially orthogonally from the first end;
• a third frame portion extending substantially orthogonally from the second end;
• a front wall extending between the second and third frame portions, wherein the front wall is configured to extend along a front side of the platen and below the support surface when the retention device is in the lowered position;
• and
• spaced apart slots extending between a top surface of the front wall and the second and third frame portions, the spaced apart slots being configured to receive the sheet substrate when the retention device is in a receiving position relative to the platen, in which the top surface of the front wall is above the support surface of the platen;
• applying a vacuum to the support surface;
• and
• forming the 3D part on the sheet substrate including extruding part and/or support material onto the sheet substrate using at least one print head.

An extrusion-based additive manufacturing system for forming 3D parts comprising:

• a vacuum platen;
• a gantry configured to move the platen along a vertical axis;
• at least one print head configured to extrude part and/or support material onto a support surface of the platen;
• a retention device including a frame configured to press two or more edge portions of a disposable sheet substrate against the support surface of the platen when the retention device is in a lowered position relative to the platen;
• and
• at least one stop member;
• the retention device configured to engage the at least one stop member when the gantry positions the platen in an engagement position along the vertical axis;
• the retention device is configured to be disengaged from the at least one stop member and placed in the lowered position when the gantry positions the platen above the engagement position;
• and
• the retention device is configured to be moved to a raised position when the gantry positions the platen below the engagement position, when the retention device is in the raised position, portions of the frame are displaced from the support surface a greater distance than when the retention device is in the lowered position.