Print Head Pressure Coupler for Additive Manufacturing Flow Control
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Solution Overview
Problem
Existing additive manufacturing systems lack effective methods for actively measuring the pressure of thixotropic materials at the point of dispensing, which is crucial for fine-tuning dispensing characteristics and preventing issues like spreading or clogging.
Innovation Solution
A system comprising an interchangeable pressure coupler and a print head that includes a pressure sensor, allowing for real-time measurement of pressure at the nozzle outlet. This data can be used in a feedback control loop to adjust the dispensing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If downward force is applied to reduce viscosity for dispensing, then material flows more readily, but traces spread and resolution deteriorates
Solution Approach 1:
The patent applies dynamic control of the downward force on the piston, adjusting it in real-time based on feedback from pressure sensors. The force is increased during initial dispensing to overcome viscosity, then reduced or modulated during trace formation to prevent spreading, thereby maintaining both flow and resolution
Solution Approach 2:
Pressure sensors positioned at the nozzle outlet provide real-time feedback on material pressure and flow characteristics. This feedback is fed back to the control system, which dynamically adjusts the downward force on the piston to optimize both dispensing flow and trace resolution throughout the printing process
2Productivity
If downward force is applied to increase flow rate, then dispensing speed improves, but pressure control precision deteriorates
Solution Approach 1:
The system dynamically adjusts the downward force on the piston based on real-time pressure feedback. During high-speed dispensing, the force is modulated to maintain consistent pressure despite increased flow demands, ensuring both productivity and pressure control precision are maintained throughout the printing process
3Manufacturing precision
If pressure is increased to prevent spreading, then trace resolution improves, but material flow becomes restricted
Solution Approach 1:
The downward force on the piston is applied in periodic pulses or cycles rather than continuously. During the dispensing phase, force is applied to maintain flow; during the pause or trace formation phase, force is reduced or removed to allow pressure buildup that prevents spreading, thereby achieving both resolution and flow rate through periodic modulation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise control over the dispensing of thixotropic materials, reducing unwanted spreading and clogging, and improving the overall resolution and reliability of additive manufacturing processes.
Implementation Method 1
A membrane constructed of an inert elastomer is embedded within the body. The membrane is contiguous with, and forms a region of, the channel such that material flowing through the channel imparts a force on the membrane in a substantially perpendicular direction to the direction of material flow.
Implementation Method 2
The thixotropic nature of PTF pastes cause their viscosity to change with respect to an applied shear force. When a substantially downward force, F, is applied on enclosed thixotropic materials during dispensing, the shear component of the force can decrease the viscosity of the materials.
Data Source
AI summary
Provided is a print head, a system and method for pressure measurements and continuous control of a flowable material in a flow path. The system includes a pressure coupler comprising a body having a channel through the longitudinal center of the body, the channel spanning between a first opening and a second opening. The pressure coupler includes a membrane embedded in the body, wherein the membrane is contiguous with, and forms a region of, the channel. Material flowing through the channel imparts a force on the membrane, and the force is transferred from the membrane to a pressure sensor adjacent to the pressure coupler. The pressure coupler and sensor may be included in a print head, whereby the pressure of a flowable material is measured during dispensing from the print head. The pressure measurements are used for continuous feedback flow control of the flowable material through the flow path.