3D Printing Extrudate Flow Control via Thermal Energy Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current 3D printing technologies face challenges in accurately controlling the flow of complex, non-Newtonian polymer-based build materials, which are often filled with inclusions, due to the lack of robust and economical flow sensing technologies, leading to difficulties in ensuring the shape, strength, and surface finish of printed parts.
Innovation Solution
A closed-loop control system that includes an extrusion head, heater, and controller to maintain a setpoint temperature, determine output flow rates based on thermal energy balance, and adjust input flow rates to prevent over- or under-extrusion, using a thermal energy balance that accounts for heat input and output from the extrusion head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If flow sensing technology is implemented to control extrudate flow, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical flow sensing devices with a thermal-based measurement approach. By measuring temperature changes in the extrusion head caused by heat transfer from the extrudate flow, the system determines flow rate without requiring additional mechanical sensors or complex sensing mechanisms, thus improving precision while avoiding increased device complexity
Solution Approach 2:
The patent introduces temperature as an intermediary parameter to indirectly measure extrudate flow rate. Instead of directly measuring flow with complex sensors, the system uses temperature changes in the extrusion head as a mediator that correlates with flow rate, providing a simpler and more economical measurement approach
2Device complexity
If thermal energy balance method is used to determine flow rate, then device complexity is reduced, but measurement precision may worsen
Solution Approach 1:
The patent implements a feedback control system where temperature measurements from the extrusion head are continuously monitored and used to calculate flow rate through thermal energy balance equations. The system uses this feedback information to adjust extrusion parameters in real-time, improving measurement precision while maintaining simple device architecture
Solution Approach 2:
The patent leverages the extrusion head's own thermal characteristics to measure flow rate. The extrusion head's temperature changes due to heat transfer from the extrudate serve as the measurement signal, eliminating the need for separate measurement devices and maintaining precision through the system's inherent thermal properties
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
This solution enables precise control of the extrusion process, preventing over- or under-extrusion and identifying fault conditions, thus ensuring consistent quality and reliability in 3D printing by accurately determining and maintaining the output flow rate.
Implementation Method 1
The heater may be configured to heat the extrusion head at a setpoint temperature to cause the transformation
Implementation Method 2
The controller may be configured to control a duty cycle of the heater, based on temperature of the extrusion head, to maintain the setpoint temperature
Implementation Method 3
A force of the incoming build material may cause extrusion of the flowable build material out from a nozzle of the extrusion head
Data Source
AI summary
An additive manufacturing apparatus, and corresponding method, determine a mass (or volume) output flow rate of extrudate used in three-dimensional (3D) printing, and such determination is insensitive to rheological properties of a material of the extrudate being printed. A thermal energy balance on a liquefying extrusion head enables a load on a heater, used to heat the extrusion head, to be related to the output flow rate of extrudate. Based on the thermal energy balance, the output flow rate may be determined based on a duty cycle of the heater. The output flow rate may be employed to affect the 3D printing to prevent over- or under-extrusion of the extrudate and to identify a fault condition.