Method for operating a printhead for a 3D printer and printhead for a 3D printer for carrying out the method

A method (200) for operating a printhead (100) for a 3D printer, wherein the method (200) comprises the following steps:

• filling (210) a cavity (40) with printable material (10) by a feed device (2);
• closing (220) an opening cross-section (21) of a piston bushing (4) by advance of a piston (3) starting from a starting position (3a) in a direction of a nozzle (8) of the printhead (100);
• converting (230) the material from a solid phase (10) via a plastic phase (11) into a liquid phase (12);
• compressing (240) the material (10, 11, 12);
• determining (250) a spring constant of the liquid phase (12);
• print preparation (260) of the liquid phase (12);
• dispensing (270) the liquid phase (12) of the material (10) from the nozzle (8) for printing a three-dimensional component (9);
• returning (280) the piston (3) to the starting position (3a) and
• repeating (290) the steps (210) to (280) until terminating the method (200),
• wherein the determining (250) of a spring constant of the liquid phase (12) comprises the following steps:
• pressure-controlled return (710) from the holding position (3d) after terminating the holding process (640) to a target position (3e), which is reached when a melt pressure (PL) reaches a target pressure (pe),
• determining a pressure difference (720) between a peak pressure (pd) and the target pressure (pe),
• determining a distance (730) between the holding position (3d) and the target position (3e), and
• calculating the spring constant (740) of the liquid phase (12).

A method (200) for operating a printhead (100) for a 3D printer, wherein the method (200) comprises the following steps:

• filling (210) a cavity (40) with printable material (10) by a feed device (2);
• closing (220) an opening cross-section (21) of a piston bushing (4) by advance of a piston (3) starting from a starting position (3a) in a direction of a nozzle (8) of the printhead (100);
• converting (230) the material from a solid phase (10) via a plastic phase (11) into a liquid phase (12);
• compressing (240) the material (10, 11, 12);
• determining (250) a spring constant of the liquid phase (12);
• print preparation (260) of the liquid phase (12);
• dispensing (270) the liquid phase (12) of the material (10) from the nozzle (8) for printing a three-dimensional component (9);
• returning (280) the piston (3) to the starting position (3a) and
• repeating (290) the steps (210) to (280) until terminating the method (200),
• wherein the print preparation (260) of the liquid phase (12) comprises the following steps:
• active decompression (810) of the liquid phase (12) by retracting the piston (3) as a function of the spring constant,
• opening (820) nozzle (8) and
• compressing (830) the liquid phase (12) at a start of printing.