Laser Powder Bed Control for Layer Height and Focus Accuracy
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Solution Overview
Problem
Existing additive processing devices face accuracy issues due to errors in layer height recognition, leading to a shift in the focal position of the laser beam, which decreases modeling accuracy over time.
Innovation Solution
An additive processing device that includes a laser head, a drive unit, a recognition unit, an estimation unit, and a control unit to recognize the height of the workpiece at multiple locations, estimate the surface shape, and adjust the stacking amount for each layer to maintain uniformity, ensuring the laser beam's focal position remains consistent with the workpiece surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the laser head moves by a fixed amount corresponding to layer thickness, then the processing speed is maintained, but the focal position shifts away from the workpiece surface due to height errors, decreasing modeling accuracy
Solution Approach 1:
The patent implements a feedback mechanism where the recognition unit continuously detects the actual height of the workpiece surface, and the control unit adjusts the laser head's movement amount based on this detected height. This closed-loop feedback system ensures the focal position remains consistent with the workpiece surface, resolving the contradiction between maintaining fixed-speed processing and ensuring focal position accuracy.
Solution Approach 2:
The patent makes the laser head's movement amount dynamic rather than fixed. The drive unit adjusts the movement distance in real-time based on the detected workpiece height variations, allowing the system to adapt to surface irregularities and maintain optimal focal positioning throughout the additive manufacturing process.
2Productivity
If the laser head moves by a fixed amount for each layer, then the processing efficiency is maintained, but height errors accumulate over layers, causing focal position shift and reduced modeling accuracy
Solution Approach 1:
The feedback mechanism detects height errors in real-time during layer formation and compensates for them by adjusting subsequent layer deposition parameters. This prevents error accumulation while maintaining continuous processing, thus preserving both productivity and modeling accuracy throughout the manufacturing process.
Solution Approach 2:
The recognition unit detects the workpiece height before the laser head completes the next layer deposition. This preliminary detection allows the control unit to pre-adjust the movement amount for the upcoming layer, preventing height errors from accumulating and ensuring consistent focal positioning throughout the process.
3Manufacturing precision
If height recognition is performed less frequently, then the processing speed is maintained, but the error correction capability is reduced, decreasing modeling accuracy
Solution Approach 1:
The patent implements periodic height recognition at strategically determined intervals during layer formation. This periodic measurement approach provides sufficient data for error correction while minimizing the time lost to measurements, balancing modeling accuracy requirements with processing efficiency.
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 enhances modeling accuracy by maintaining a consistent focal position, reducing errors and improving the uniformity of the workpiece height, resulting in better additive manufacturing outcomes compared to conventional methods.
Implementation Method 1
a laser head configured to supply the powder material to the workpiece and irradiate the workpiece with a laser beam
Implementation Method 2
the portion of the workpiece irradiated with the laser beam melts. When the powder material is supplied to the melted portion, the powder material melts and solidifies
Data Source
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AI summary
There is provided an additive processing device that models a workpiece by melting a supplied powder material and forming layers of the melted powder material. The additive processing device includes a laser head configured to supply the powder material to the workpiece and irradiate the workpiece with a laser beam, a drive unit configured to drive the laser head, a recognition unit configured to recognize a height of the workpiece in a laminating direction at a plurality of locations while the laser head is forming a predetermined N-th layer (N being a natural number) of the workpiece, an estimation unit configured to estimate a surface shape of the N-th layer of the workpiece based on the recognized heights at the plurality of locations, and a control unit configured to control the laser head and the drive unit. The control unit is configured to recognize, based on the estimated surface shape, a low location at which the height of the workpiece in the laminating direction is lower than at another location, and set a stacking amount higher at the low location than at the other location in modeling of a N+l-th layer.