3D Printer Force Sensing for Surface Probing and Extrusion Error Detection
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Solution Overview
Problem
Existing 3D printing technologies face challenges in accurately printing on non-flat or uneven surfaces and detecting extrusion errors, such as clogging or material depletion, due to the soft and sensitive nature of biological materials used in additive manufacturing.
Innovation Solution
A 3D printer equipped with a force sensing system that allows for print surface probing and error detection, using sensors like load cells or optical sensors to determine the Z-position and orientation of the print bed, and a control element to record and adjust for surface irregularities and extrusion issues, enabling closed-loop printing and calibration for stable surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If force sensing sensors are integrated into the 3D printer system, then extrusion error detection and print surface probing capabilities are improved, but device complexity increases
Solution Approach 1:
The force sensing system is designed to perform multiple functions: it detects extrusion errors by monitoring unexpected forces during material deposition, probes print surface topography by measuring contact forces at different Z-positions, and provides feedback for closed-loop printing control. This multi-functionality approach consolidates what could be separate systems into a unified sensor framework, improving reliability while managing complexity through functional integration.
Solution Approach 2:
The force sensing sensors provide real-time feedback during the printing process. The control element continuously monitors force readings and compares them against expected values to detect extrusion errors. The system also uses force feedback to determine print surface Z-positions and adjusts extrusion parameters accordingly, creating a closed-loop control system that enhances reliability through continuous monitoring and correction.
2Adaptability or versatility
If print surface probing is implemented to print on non-flat surfaces, then adaptability to different surface conditions is improved, but manufacturing precision requirements increase
Solution Approach 1:
Before actual printing begins, the system performs a probing phase where the extrusion element or sensor tool-head touches the print surface at multiple predetermined positions to map the topography. This preliminary action creates a digital model of the surface geometry, allowing the printing path and Z-positions to be pre-adjusted. By performing this surface characterization beforehand, the system adapts to non-flat surfaces without requiring high precision during the main printing process, as the compensation has already been planned.
Solution Approach 2:
The system addresses surface irregularities by introducing Z-dimensional adjustments based on XY plane probing data. Instead of trying to maintain perfect contact in a single plane, the system varies the Z-position of the extrusion element according to the measured surface topography, effectively printing on a virtual flat plane that accounts for underlying surface variations.
3Reliability
If closed loop printing with force sensing is used to detect extrusion errors, then printing reliability is improved, but use of energy increases
Solution Approach 1:
The force sensing system operates periodically rather than continuously at full capacity. During normal printing, force monitoring occurs at regular intervals corresponding to extrusion events or at key path points. Surface probing is performed as discrete periodic measurements before printing or between layers. This periodic operation reduces energy consumption compared to continuous high-resolution sensing while maintaining sufficient reliability for error detection through strategically timed measurements.
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 allows for precise printing on any stable surface, detects extrusion errors in real-time, and ensures accurate deposition of biological materials, preventing defects and ensuring consistent construct quality.
Implementation Method 1
at least one sensor arranged to sense a force applied to the print bed by the extrusion element, or vice versa
Implementation Method 2
the force sensing sensor arranged at the print bed comprises a scale
Data Source
AI summary
The present disclosure relates to a 3D printer (1) for 3D printing of a construct. The 3D printer (1) has a print bed (2). The 3D printer further comprises at least one actuating tool head (3) with an extrusion element (4), wherein the extrusion element and the print bed are movable in relation to each other. The 3D printer also comprises at least one sensor (5) arranged to sense a force applied to the print bed (2) by the extrusion element (4), or vice versa. The 3D printer additionally comprises a control element (7) arranged to detect when the sensed force exceeds a predetermined value and to record a position of the print bed or extrusion element related to the detection that the predetermined value is exceeded. The present disclosure also relates to corresponding methods and computer programs.