Phase change ink printing system utilizing a composite waveform

A method of manufacturing a three-dimensional (3D) article comprising:

• providing a 3D printing system including:
• a build plate coupled to a vertical movement mechanism;
• a drop on demand piezo (DODP) printhead, the DODP printhead including an array of piezoelectric (piezo) actuators;
• a horizontal movement mechanism configured to impart relative lateral motion between the DODP printhead and the build plate;
• a supply coupled to the DODP printhead containing a phase change ink;
• operating the supply and the DODP printhead to maintain a liquid state of the phase change ink;
• operating the vertical movement mechanism to position an upper surface at a build plane;
• operating the horizontal movement mechanism to impart a scanning motion of the printhead with respect to the upper surface;
• concurrent with operating the horizontal movement mechanism, operating the array of piezo actuators to deliver ink drops to pixel locations upon the upper surface, for individual ones of the array of piezo actuators and individual ones of the ink drops:
• applying a secondary waveform to the piezo actuator including a secondary positive voltage pulse having a maximum magnitude (VSP) followed by a negative voltage pulse having a maximum magnitude (VSN);
• applying a primary waveform to the piezo actuator including a primary positive voltage pulse having a maximum magnitude (VPP) followed by a primary negative voltage pulse having a maximum magnitude (VPN);
• VPP>VSP and VPN>VSN;
• further operating the vertical movement mechanism, the horizontal movement mechanism, the supply, and the printhead to complete fabrication of the 3D article in a layer-by-layer manner.

A three-dimensional (3D) printing system for manufacturing a 3D article comprising:

• a build plate coupled to a vertical movement mechanism;
• a drop on demand piezo (DODP) printhead, the DODP printhead including an array of piezoelectric (piezo) actuators;
• a horizontal movement mechanism configured to impart relative lateral motion between the DODP printhead and the build plate;
• a supply coupled to the DODP printhead and containing a phase change ink;
• a controller programmed to:
• operate the supply and the DODP printhead to maintain a liquid state of the phase change ink;
• operate the vertical movement mechanism to position an upper surface at a build plane;
• operate the horizontal movement mechanism to impart a scanning motion of the printhead with respect to the upper surface;
• concurrent with operating the horizontal movement mechanism, operate the array of piezo actuators to deliver ink drops to pixel locations upon the upper surface, for individual ones of the array of piezo actuators and individual ones of the ink drops:
• select between and operating in one of two operating modes including:
• a nominal ejection mode in which a primary waveform is applied to the piezo actuator including a primary positive voltage pulse having a maximum magnitude (VPP) followed by a primary negative voltage pulse having a maximum magnitude (VPN), the piezo actuator in response ejecting a primary ink drop having a primary drop volume magnitude (VOLP);
• a composite ejection mode in which a composite waveform is applied to the piezo actuator including a secondary waveform followed by a primary waveform, the secondary waveform including a secondary positive voltage pulse having a maximum magnitude (VSP) followed by a negative voltage pulse having a maximum magnitude (VSN), the composite waveform ejecting a secondary ink drop having a secondary drop volume magnitude (VOLS) followed by the primary ink drop to form a composite ink drop having a composite ink drop volume magnitude that is at least at least 150% of the primary drop volume magnitude (VOLP);
• VPP>VSP and VPN>VSN;
• further operating the vertical movement mechanism, the horizontal movement mechanism, the supply, and the printhead to complete fabrication of the 3D article in a layer-by-layer manner.