Additive Manufacturing Optical Pickup Head for High Resolution
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Solution Overview
Problem
Current vat photo-polymerization processes in additive manufacturing are limited by the optical resolution of light sources, restricting the structural precision of the final products due to scanning distance, spot size, and depth of focus limitations.
Innovation Solution
An additive manufacturing apparatus featuring a vat, a lifting platform, a linear conveying module, and an optical pickup head with a focusing unit including a laser source, objective lens, and collimator lens, which allows for high optical resolution by scanning the laser beam in a two-dimensional plane and using multiple laser beams to cure liquid resin, and a detecting unit to correct for vibrations and maintain focus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a laser beam is used to scan and cure liquid resin point-by-point, then structural detail can be achieved, but the scanning distance, spot size, and depth of focus cannot be effectively reduced due to optical resolution limitations
Solution Approach 1:
The patent transitions from point-by-point scanning in a single plane to multi-layer scanning in three-dimensional space. The optical pickup head scans multiple layers of the resin vat simultaneously by moving along the Z-axis while maintaining focused laser beams at different depths, effectively adding a dimensional aspect to overcome optical resolution limitations.
Solution Approach 2:
The patent divides the curing process into multiple discrete layers along the Z-axis. Instead of attempting to cure the entire volume at once or scanning point-by-point in a single plane, the system segments the resin vat into multiple focal layers, curing each layer with optimized laser parameters while maintaining high optical resolution at each segment.
2Productivity
If a projector is used to cure entire layers at once, then processing speed improves, but optical diffraction limits the structural resolution of the solid object
Solution Approach 1:
The patent combines the advantages of both scanning and projection methods by implementing multi-layer simultaneous scanning. The optical pickup head moves along the Z-axis to access multiple focal planes, enabling parallel processing of multiple layers while maintaining the high precision of laser scanning at each layer, thus achieving both speed and resolution.
Solution Approach 2:
The system dynamically adjusts the focal position of the laser beam along the Z-axis to match the depth of different resin layers. By continuously varying the focus depth in sync with the lifting platform's movement, the system maintains optimal optical resolution throughout the entire build volume while processing multiple layers efficiently.
3Manufacturing precision
If the lifting platform moves vertically away from the vat, then layers can be built cumulatively, but maintaining focus and scanning precision becomes more difficult over distance
Solution Approach 1:
The patent incorporates a detecting unit that monitors the position of the lifting platform and provides feedback to the control system. This feedback mechanism enables real-time adjustment of the optical pickup head's position and the laser beam's focal point, compensating for the increasing scanning distance and maintaining consistent focus and precision throughout the building process.
Solution Approach 2:
The system dynamically adjusts the focal length and position of the objective lens to compensate for the changing distance between the optical pickup head and the resin surface as the lifting platform moves upward. This dynamic focusing ensures that the laser beam remains sharply focused on each layer regardless of the vertical displacement.
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 the structural resolution of the produced solid objects by achieving higher optical resolution and precision, allowing for more detailed and accurate three-dimensional structures compared to conventional methods.
Implementation Method 1
a laser beam performs stereo-lithography on the resin by scanning the resin point-by-point to cure a layer of the resin
Implementation Method 2
at least one first objective lens spaced apart from the first laser source, and a first collimator lens. The first collimator lens is disposed between the first laser source and the at least one first objective lens, such that the laser beam passes through the first collimator lens and the at least one first objective lens to strike the liquid resin
Data Source
AI summary
An additive manufacturing apparatus is adapted to produce a solid object from a liquid resin and includes a vat, a lifting platform, an optical pickup head, and a planar scanning module mounted with the optical pickup head and operable to move the optical pickup head on a two-dimensional plane. The optical pickup head includes a focusing unit that has a first laser source for producing a laser beam, at least one first objective lens, and a first collimator lens disposed between the first laser source and the at least one first objective lens, such that the laser beam passes through the first collimator lens and the at least one first objective lens to strike and cure the liquid resin during movement of the lifting platform away from the vat.