3D Printer Nozzle Tip Calibration Using Eddy Current Sensing
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Solution Overview
Problem
Existing 3D printing technologies face challenges in accurately locating the tip orifice of a nozzle, especially when swapping print heads, leading to errors in extrusion and layer formation due to deviations in nozzle and tip orifice positions.
Innovation Solution
An induction sensing method using an eddy current sensor to determine the center of the nozzle tip surface and an optical sensor to locate the inner diameter of the tip orifice, followed by XYZ compensation to adjust toolpaths for precise nozzle alignment, enabling fast and accurate calibration of nozzle positions during tool changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mechanical positioning methods are used for nozzle tip calibration, then the calibration process is simple, but the positioning accuracy is insufficient (greater than 15 µm error in xy plane)
Solution Approach 1:
The patent replaces mechanical positioning methods with electromagnetic sensing methods. Specifically, it uses eddy current sensors to detect the position of the nozzle tip surface and optical sensors to detect the tip orifice location. This substitution enables sub-15 µm positioning accuracy by eliminating mechanical measurement errors and providing non-contact, high-precision electromagnetic field-based detection.
Solution Approach 2:
The patent introduces electromagnetic fields as intermediaries between the measurement system and the nozzle tip. Eddy current sensors generate electromagnetic fields that interact with the conductive nozzle tip surface to determine its position, while optical sensors use light fields to detect the tip orifice. These intermediary fields enable precise measurement without direct mechanical contact.
2Productivity
If manual calibration procedures are used for tool changes, then the system is easy to operate, but the calibration time is excessive and productivity is reduced
Solution Approach 1:
The patent performs preliminary calibration of the nozzle tip position and tip orifice location using electromagnetic and optical sensors before actual printing begins. The system pre-determines the relationship between the nozzle tip surface position (detected by eddy current sensor) and the tip orifice position (detected by optical sensor), storing this calibration data for rapid tool changes. This preliminary action eliminates the need for time-consuming manual calibration during production.
Solution Approach 2:
The calibration system performs automatic self-calibration using the eddy current sensor and optical sensor to detect nozzle tip characteristics and compute position compensation values without human intervention. The system automatically processes the detected signals, calculates the tip orifice location relative to the nozzle tip surface, and updates the positioning data, enabling rapid tool changes while maintaining high precision.
3Manufacturing precision
If nozzle tip position is not accurately located, then the system structure remains simple, but printing errors occur and manufacturing precision deteriorates
Solution Approach 1:
The patent replaces simple mechanical positioning with electromagnetic sensing systems. Eddy current sensors provide non-contact measurement of the nozzle tip surface position with sub-15 µm accuracy, and optical sensors detect the tip orifice location. This substitution eliminates mechanical measurement errors and provides the precision needed for accurate layer formation and material deposition.
Solution Approach 2:
The system uses eddy current sensors to continuously monitor the nozzle tip position and provides feedback for real-time compensation. The sensor detects changes in the electromagnetic field caused by the nozzle tip position, and this feedback is used to adjust the positioning system and maintain manufacturing precision during printing operations.
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
Ensures accurate and repeatable nozzle positioning with less than 15 µm accuracy in the xy plane and 10 µm in the z direction, minimizing printing errors and ensuring consistent layer formation and material deposition.
Implementation Method 1
moving the metal nozzle over the eddy current sensor in a predetermined motion path above the eddy current sensor while the eddy current sensor remains stationary and samples the magnitude of inductance in a generated inductive field
Implementation Method 2
the eddy current sensor remains stationary and samples the magnitude of inductance in a generated inductive field
Data Source
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AI summary
An induction sensing method for identifying the center of a tip surface of a nozzle (604) of print head of a 3D printer includes providing an eddy current sensor (610) in a fixed position and providing a metal nozzle (604) with a tip orifice in a main body and a tip surface about the tip orifice. The method includes moving the metal nozzle (604) over the eddy current sensor (610) in a predetermined motion path above the eddy current sensor (610) while the eddy current sensor remains stationary and samples the magnitude of inductance in a generated inductive field, thereby generating a curve representing the inductive field. The method includes identifying a maximum amplitude of the curve to identify the center of the tip surface.