Lithography Additive Manufacturing Light Engine Synchronization
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Solution Overview
Problem
Current lithography-based additive manufacturing techniques face challenges in achieving high surface quality, small feature resolution, and thermo-mechanical material properties, particularly with large building areas and photopolymers that have low reactivity and high viscosity, leading to accuracy limitations and instability in the printing process.
Innovation Solution
A device and method that enable precise manufacturing of 3D structures with a light engine and material transport unit, allowing relative movement between the light engine and building platform, synchronized by a linear encoder for accurate exposure control, and using a flexible carrier film with adjustable tension and heating to manage resin viscosity and composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If vat-based stereolithography with large resin vats is used to achieve large building areas, then the building area is increased, but manufacturing precision deteriorates due to optical limitations and timing constraints of laser scanning systems
Solution Approach 1:
The patent divides the large building area into multiple smaller exposure fields that can be processed sequentially. The light source scans across the resin surface in a controlled manner, exposing one region at a time according to a predetermined pattern. This segmentation allows the system to maintain high precision for each small region while achieving large overall building area through systematic progression across multiple fields.
Solution Approach 2:
The patent employs a dynamic scanning light source that moves across the resin surface rather than using a static large-format light system. The light source is scanned across the resin in a controlled manner, allowing the system to adapt to different building area sizes while maintaining consistent exposure parameters and timing for each local region, thereby preserving manufacturing precision.
2Measurement precision
If thin resin layers are generated between submerged structure and free surface to achieve high surface quality, then surface quality is improved, but manufacturing precision deteriorates due to viscosity and surface tension phenomena of the resin
Solution Approach 1:
The patent applies a preliminary coating of photopolymer resin onto the building platform before the actual printing process begins. This preliminary layer serves as a stable base that defines the initial surface quality and provides a reference plane. By preparing this foundational layer in advance with controlled thickness and uniformity, the system establishes a precise starting point that improves subsequent layer deposition accuracy despite resin viscosity and surface tension effects.
3Quantity of substance
If photopolymer resin is stored in large vats for extended periods, then material availability is improved, but reliability deteriorates due to chemical instability and degradation of the resin
Solution Approach 1:
The patent extracts and removes the resin from the bulk vat storage environment and applies it directly to the building platform in a controlled, limited quantity. By taking the resin out of the large-volume storage condition and using it immediately in a controlled application process, the system minimizes exposure to degradation factors while maintaining process stability. This approach allows the system to work with smaller, more stable quantities of resin that do not suffer from long-term chemical instability.
4Strength
If photopolymer resin with low reactivity and high viscosity is used to achieve excellent thermo-mechanical properties, then material performance is improved, but ease of manufacture deteriorates due to processing difficulties
Solution Approach 1:
The patent changes the physical parameters of the photopolymer resin by controlling the exposure conditions and environmental factors during the printing process. By adjusting parameters such as temperature, humidity, and exposure time, the system modifies the resin's viscosity and reactivity temporarily, enabling it to be processed more easily while maintaining its excellent thermo-mechanical properties in the final cured structure. The controlled environment compensates for the resin's inherent low reactivity and high viscosity.
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 allows for high accuracy, large building platform capabilities, and stable processing of lowly cross-linked photopolymer networks with strong secondary bonds, achieving excellent thermo-mechanical properties and process scalability without significant parameter changes.
Implementation Method 1
Different light sources are typically used in order to induce photopolymerization of the liquid photopolymer resin layer
Implementation Method 2
By precisely heating such a material supporting element, even photopolymer formulations of various viscosities (e.g., high viscous photopolymer formulations) can be processed
Data Source
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AI summary
A device for the lithography-based additive manufacturing of three-dimensional structures, comprises a building platform defining a building plane, a light engine designed for the dynamic patterning of light in an exposure field of said light engine, a material transport unit comprising a first drive means for transporting a material layer across the exposure field, second drive means for causing relative movement of the light engine and the building platform along a displacement path extending parallel to the building plane, a linear encoder for sensing a position and/or a velocity of the light engine relative to the building platform, control means configured to adjust the feeding rate of a pattern data feeding means based on the position or the velocity sensed by the linear encoder.