Inclined-Pixel Projector Scanning for Large-Area Stereolithography
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Solution Overview
Problem
The challenge of increasing the size and area of three-dimensional objects in stereolithography leads to longer manufacturing times and reduced exposure accuracy, necessitating improvements in productivity and stability.
Innovation Solution
A stereolithography apparatus with a projector that inclines its pixels to offset exposure light in a specific pattern, allowing for sequential exposure of strip regions with alternating movements to form joint portions between layers, and a dispenser and sweeper to laminate slurry films with controlled gravity alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size and area of the three-dimensional object are increased, then the productivity and manufacturing capability are improved, but the manufacturing time increases and exposure accuracy deteriorates
Solution Approach 1:
The exposure process is divided into multiple scan lines that are exposed sequentially. Each scan line is exposed independently by moving the projector in the second direction, allowing the large-area object to be manufactured through repeated exposure of segmented regions, thereby maintaining exposure accuracy while handling large objects
Solution Approach 2:
The projector is inclined with respect to the second direction, creating an offset between adjacent pixels in the first direction. This dimensional offset allows the formation of joint portions between adjacent strip regions, enabling seamless stitching of multiple exposed regions while maintaining overall exposure accuracy across the entire large-area object
2Volume of moving object
If the size and area of the three-dimensional object are increased, then the manufacturing capability is improved, but the manufacturing time increases
Solution Approach 1:
The projector alternates between forward movement and backward movement in the second direction with intervening step movements in the first direction, continuously exposing different strip regions without idle time. This continuous scanning exposure process efficiently covers the entire large-area object, reducing total manufacturing time while maintaining exposure quality
Solution Approach 2:
The large object is divided into multiple strip regions that are exposed in parallel through the inclined pixel arrangement. Multiple scan lines can be processed simultaneously or in rapid succession, significantly reducing the total exposure time compared to sequential line-by-line exposure of the entire area
3Area of stationary object
If sequential exposure of multiple strip regions is performed with alternating movements, then large-area objects can be manufactured, but joint portions between regions may affect manufacturing accuracy
Solution Approach 1:
The projector is deliberately inclined at an angle with respect to the second direction, creating an asymmetric offset between adjacent pixels in the first direction. This asymmetric arrangement ensures that joint portions between adjacent strip regions are formed at different in-plane positions across multiple layers, preventing cumulative positioning errors and maintaining manufacturing accuracy at接缝 areas
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 reduces the impact of joint portions on manufacturing accuracy, enabling high-dimensional accuracy and minimizing biased load on the manufacturing table, while ensuring efficient production of large objects.
Implementation Method 1
exposure of a necessary region from above by laser scanning for curing of the resin
Data Source
AI summary
A projector of an exposer is movable in a second direction orthogonal to a first direction in a posture inclined so that center positions of two adjacent pixels are offset in the first direction, is configured to switch ON-OFF states of exposure light each time the projector moves a distance corresponding to the drawing pitch in the second direction, exposes a photo-curable material in a predetermined drawing area sequentially for a plurality of strip regions each extending in the second direction, and forms, in a case where a plurality of layers of the photo-curable material are each exposed while being laminated to obtain a three-dimensional object, a joint portion of two adjacent strip regions of the plurality of strip regions and causes an in-plane position of the joint portion to differ between at least two layers of the plurality of layers.