Flexible actuation with intrinsic sensing for ram extrusion 3D printing

Conventional actuation mechanisms used in liquid deposition modeling (LDM) technology limit the flow handling capability and the visibility of the printing materials' properties. This work presents a flexible actuation system with intrinsic sensing for a ram extrusion printhead used in LDM technology. A mathematical model is used to design and simulate the printhead. The experimental results demonstrate the system's ability to control the extrusion flow in two modes. The pressure control mode is favorable for the flow in a transient state such as flushing. The volumetric control mode provides a constant printed line width with less than 0.1-mm deviation between each tested material (biogel, chocolate fudge, and silicone sealant). A lower standard deviation for printed lines in the volumetric control mode indicates more precise line printing. The system also incorporates real-time monitoring of extrusion pressure and flow rate. The intrinsic capability to detect printing material properties is validated in both simulation and experiment. It provides valuable insights for further optimization of the printing process. The proposed system offers the advantage of improved pressure and flow control as well as the ability to monitor and respond to the properties of printing material.