Laser Powder Deposition Control for Layer Height Uniformity
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Solution Overview
Problem
Existing additive processing devices face accuracy issues due to errors in layer height recognition, leading to decreased modeling accuracy as the focal position of the laser beam shifts away from the workpiece surface, causing uneven layer formation.
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 ensure uniform height by increasing the stacking amount at lower locations, thereby maintaining the focal position on the workpiece surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
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 causing modeling accuracy to decrease
Solution Approach 1:
The patent implements a feedback mechanism where the recognition unit continuously monitors the actual workpiece surface height, and the control unit adjusts the laser head movement amount based on this feedback to maintain the focal position on the workpiece surface, resolving the contradiction between fixed-speed processing and accuracy maintenance
Solution Approach 2:
The system transitions from static fixed-step movement to dynamic adaptive movement by continuously adjusting the laser head displacement based on real-time surface height measurements, allowing the focal position to remain on the workpiece surface despite variations in layer height
2Manufacturing precision
If the laser head moves less to maintain focal position, then modeling accuracy is improved, but the productivity decreases due to frequent position adjustments
Solution Approach 1:
The patent maintains continuous useful action by performing height recognition and adjustment operations during the layer formation process itself, rather than interrupting the process for separate measurement and adjustment steps, thus minimizing impact on overall processing speed
3Manufacturing precision
If height recognition is performed frequently to maintain accuracy, then modeling precision is improved, but the measurement time and processing overhead increase
Solution Approach 1:
The system employs periodic height recognition at strategically selected positions during layer formation, balancing the need for accuracy information with the time cost of measurements, rather than continuous measurement at every point
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, resulting in more uniform workpiece height and improved additive manufacturing efficiency.
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
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+1-th layer.