Stereolithography Optical Group Segmentation for Speed and Precision
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Solution Overview
Problem
Stereolithography machines face limitations in achieving high-definition objects quickly due to issues with irregular edges, uniform light intensity, and prolonged solidification times, particularly in existing optical systems that either lack precision or require extensive mechanical movement.
Innovation Solution
A stereolithography machine incorporating a dual optical sub-group system, where a Digital Light Processing (DLP) projector provides rapid, high-definition exposure for large areas and a galvo head or micro-opto-electro-mechanical system (MOEMS) allows precise, high-definition exposure along continuous trajectories, enabling adaptive control for optimal speed and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a matrix of mirrors (DLP projector) is used to illuminate the entire reference surface simultaneously, then the solidification speed is improved (single exposure per layer), but the manufacturing precision deteriorates (irregular edges and outer surfaces)
Solution Approach 1:
The optical group is divided into two distinct sub-groups: a first optical sub-group (DLP projector with matrix of mirrors) for rapid illumination of large areas, and a second optical sub-group (galvo head or MOEMS) for high-precision scanning of continuous trajectories. This segmentation allows each sub-group to specialize in its strengths, resolving the contradiction between speed and precision.
Solution Approach 2:
Different portions of the reference surface are treated differently based on their requirements: large flat areas are illuminated by the first optical sub-group for speed, while portions requiring high definition (edges, contours, curved surfaces) are processed by the second optical sub-group for precision. This local differentiation resolves the contradiction by applying the appropriate method to each specific area.
2Manufacturing precision
If a galvo head with mechanical mirrors is used to direct the light beam point-by-point, then the manufacturing precision is improved (continuous trajectories and high definition), but the productivity deteriorates (prolonged solidification times)
Solution Approach 1:
The optical group is divided into two distinct sub-groups: a first optical sub-group (DLP projector with matrix of mirrors) for rapid illumination of large areas, and a second optical sub-group (galvo head or MOEMS) for high-precision scanning of continuous trajectories. This segmentation allows each sub-group to specialize in its strengths, resolving the contradiction between speed and precision.
Solution Approach 2:
Different portions of the reference surface are treated differently based on their requirements: large flat areas are illuminated by the first optical sub-group for speed, while portions requiring high definition (edges, contours, curved surfaces) are processed by the second optical sub-group for precision. This local differentiation resolves the contradiction by applying the appropriate method to each specific area.
3Manufacturing precision
If a fixed laser source with mechanical movement device is used, then the manufacturing precision is improved (ability to direct beam anywhere), but the device complexity increases (mechanical components requiring maintenance)
Solution Approach 1:
The patent replaces the mechanical movement device with an optical scanning system using galvanometric mirrors or MOEMS. This substitution eliminates complex mechanical components that require maintenance while maintaining the ability to direct the light beam to any point on the reference surface with high precision through electromagnetic control of mirror angles.
Solution Approach 2:
The second optical sub-group (galvo head or MOEMS) serves multiple functions: it can scan continuous trajectories for high-precision work, it can be integrated with the first optical sub-group in a unified control system, and it provides beam positioning flexibility without mechanical movement. This multi-functionality reduces overall system complexity while maintaining precision capabilities.
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 configuration enables the production of high-definition three-dimensional objects quickly by selectively using either sub-group based on the object's characteristics, balancing execution speed and quality, and reducing maintenance needs.
Implementation Method 1
a first optical sub-group (41) configured to be exposed to a predetermined radiation (RL) so as to instantaneously and integrally project the image of a first predetermined portion to be solidified of a three-dimensional object (O) onto a reference surface (SR)
Implementation Method 2
a second optical sub-group (42) configured to selectively convey the predetermined radiation towards a point of the reference surface (SR) and to move the point so as to progressively expose a second predetermined portion to be solidified of the reference surface (SR)
Implementation Method 3
making three-dimensional objects through a plurality of juxtaposed layers (S), wherein each layer is obtained by selective solidification of a fluid substance (R) in the areas corresponding to the volume of the object to be produced
Data Source
AI summary
A stereolithography machine (1) for making a three-dimensional object (O) that comprises a container (2) for a fluid substance (R), a source (3, 31, 32) of the predetermined radiation (RL, RL1, RL2), an optical group (4) configured to direct the radiation (RL, RL1, RL2) towards a reference surface (SR) of the fluid substance (R), and a control logic unit (5) configured to control the optical group (4) and/or the radiation source (3, 31, 32) so as to expose at least one portion of the reference surface (SR) to the radiation (RL, RL1, RL2). The stereolithography machine provides that the optical group (4) comprises a first optical sub-group (41) configured to be exposed to the radiation (RL, RL1, RL2) so as to instantaneously project the image of a first portion to be solidified onto the reference surface (SR) and a second optical sub-group (42) configured to selectively convey the radiation (RL, RL1, RL2) towards a point of the reference surface (SR) and to move such a point so as to progressively expose a second portion to be solidified of the reference surface (SR).