Multi-Laser Heating for Fiber Thermoplastic Weld Uniformity
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Solution Overview
Problem
The existing additive manufacturing systems face challenges in producing quality welds when fabricating articles using fiber-reinforced thermoplastic feedstock, as the laser heating method fails to account for the varying geometry and thermal properties of the workpiece, leading to inconsistent heating and poor weld quality.
Innovation Solution
The use of two or four dedicated lasers, one for heating the feedstock and one or two for heating the workpiece, respectively, allows for independent control of heating parameters, including power adjustment and beam steering, to ensure precise temperature management and consistent welding, even on complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single laser is used to heat both feedstock and workpiece, then the device complexity is reduced, but the manufacturing precision and weld quality deteriorate due to inability to independently control heating parameters
Solution Approach 1:
The heating system is segmented into multiple independent laser units: one laser dedicated to heating the feedstock and one or two lasers dedicated to heating the workpiece. This segmentation allows independent control of heating parameters for each component, enabling precise temperature management and consistent weld quality without requiring a single complex laser system.
2Power
If laser power is increased to ensure adequate heating, then the heating effectiveness improves, but the risk of overheating and material damage increases
Solution Approach 1:
Different laser units are allocated different power levels according to the specific heating requirements of each component. The feedstock heating laser and workpiece heating lasers operate at independently optimized power levels, ensuring adequate heating effectiveness for each component while preventing overheating and material damage through localized power control.
Solution Approach 2:
The system dynamically adjusts laser heating parameters including power, beam steering, and exposure time to match the varying thermal properties and geometry of the workpiece and feedstock. This parameter optimization ensures adequate heating while preventing overheating damage.
3Power
If the laser beam is focused on a small area to achieve high heating intensity, then the heating efficiency improves, but the heating uniformity across the entire component deteriorates
Solution Approach 1:
The system uses multiple laser units positioned at different locations and angles to heat different areas of the feedstock and workpiece simultaneously. This multi-dimensional approach distributes the high-intensity heating across the entire component surface, maintaining both heating efficiency and temperature uniformity.
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 approach enhances the quality of welds by ensuring each segment of feedstock and portion of the workpiece is properly heated and tamped, reducing defects and improving the overall manufacturing process efficiency.
Implementation Method 1
When the temperature of a thermoplastic filament is below its resin softening point, the filament is long, thin, stiff, and not sticky—like a dry spaghetti noodle. In contrast, when the temperature of the filament is above its resin softening point but below its melting point, the filament is long, thin, flexible, and sticky—like a wet spaghetti noodle.
Data Source
AI summary
An additive manufacturing system is disclosed that comprises two or more lasers for precisely heating a fiber-reinforced thermoplastic feedstock and a fiber-reinforced thermoplastic workpiece in preparation for depositing and tamping the feedstock onto the workpiece. The system employs feedforward, a variety of sensors, and feedback to ensure that the feedstock and workpiece are properly heated.