3D Printing Extrusion Control via Hydraulic Capacitance
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Solution Overview
Problem
Existing 3D printing technologies face challenges in accurately controlling the extrusion of build materials, leading to over- or under-extrusion issues due to variations in speed and direction of stage motors, which result in undesirable geometric responses and print errors.
Innovation Solution
A system comprising an extrusion assembly with an actuator and controller that uses hydraulic capacitance and resistance values to adjust the input control value, enabling precise control of the output flow to match a target flow, accounting for non-Newtonian characteristics and mechanical interactions within the extrusion assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional extrusion control methods are used, then the system is simple to operate, but extrusion precision deteriorates due to over- or under-extrusion
Solution Approach 1:
The patent implements a feedback control system where the controller continuously monitors the actual extrusion flow rate and compares it with the target flow rate. Based on this feedback, the controller dynamically adjusts the input control value to the actuator to compensate for deviations caused by hydraulic capacitance and resistance variations, thereby maintaining high extrusion precision without excessive system complexity
Solution Approach 2:
The patent changes the control parameter from direct position or speed control to hydraulic parameter control (input control value based on hydraulic capacitance and resistance). By calculating the input control value as a function of hydraulic capacitance, hydraulic resistance, and target flow rate, the system adapts to material and mechanical variations, improving extrusion precision while keeping the control logic manageable
2Productivity
If stage motor speed and direction are varied, then productivity is improved, but extrusion accuracy deteriorates due to geometric responses
Solution Approach 1:
The patent calculates and applies compensation values in advance based on pre-characterized hydraulic capacitance and resistance parameters. Before actual extrusion, the controller determines the appropriate input control value considering the target flow rate and hydraulic properties, allowing the system to maintain geometric accuracy even when operating at high printing speeds with varied stage motor movements
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 effectively mitigates over- and under-extrusion by accurately matching the output flow with the target flow, improving the precision and quality of 3D printed objects by accounting for the complex interactions and characteristics of the build material and extrusion mechanism.
Implementation Method 1
The extrusion head may be configured to heat the build material within a melting zone of the extrusion head prior to extruding an output flow of the build material
Implementation Method 2
The extrusion head may be configured to heat the build material within a melting zone of the extrusion head prior to extruding an output flow of the build material
Data Source
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AI summary
Systems, methods, and apparatus are introduced for controlling an output flow of a build material from an extrusion assembly used for printing a three-dimensional (3D) object. Control of the output flow is based on an input control value that may be a function of a hydraulic capacitance and a hydraulic resistance, representing hydraulic capacitance values and hydraulic resistance values, respectively, associated with the build material, the extrusion assembly, or a combination thereof at one or more locations of the extrusion assembly relative to a melting zone of an extrusion head of the extrusion assembly as well as a target output flow. The input control value enables the output flow to match the target output flow. The hydraulic capacitance and resistance values account for interaction of the build material and a mechanical mechanism of the extrusion assembly driving extrusion of the build material. The hydraulic capacitance and resistance values may depend upon interaction between the build material and mechanics of the extrusion assembly as well as an internal wetted geometry of the extrusion assembly.