Oscillating Exposure Mask for Uniform Curing in 3D Printing
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Solution Overview
Problem
Existing methods for producing three-dimensional objects by layer-by-layer solidification using radiation exposure masks face challenges such as inhomogeneous light intensity distribution, uneven hardening depth across different cross-sectional areas, and insufficient green body hardness, particularly affecting filigree structures, which can lead to incomplete formation and reduced surface quality.
Innovation Solution
The method involves oscillating the exposure mask relative to the construction plane during exposure, using a single digital exposure mask with a 2-bit bitmap that assigns 'transparent' and 'non-transparent' bit values to control radiation intensity, and employing exposure textures with specific patterns to ensure uniform energy input and edge smoothing, thereby eliminating the need for multiple exposures and gray value control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single exposure mask is used for layer-wise solidification, then the manufacturing process is simplified and productivity is improved, but the light intensity distribution becomes inhomogeneous leading to uneven curing depth
Solution Approach 1:
The patent applies dynamics by oscillating the exposure mask relative to the construction plane during the exposure process. This dynamic movement transforms the static mask into a moving component that continuously varies the exposure pattern, thereby homogenizing the light intensity distribution across different cross-sectional areas and achieving uniform curing depth while maintaining single-mask productivity
Solution Approach 2:
The oscillation of the exposure mask during exposure represents periodic action. The mask moves back and forth in a regular pattern, creating periodic variations in the exposure geometry that average out the intensity differences across the build plane, resulting in homogeneous curing throughout the layer
2Manufacturing precision
If gray value control or multiple exposures are used to achieve uniform curing depth, then curing uniformity is improved, but the exposure time per layer increases significantly
Solution Approach 1:
Instead of using multiple static masks or gray value control that require sequential processing, the patent employs a single mask that oscillates dynamically during exposure. This approach achieves uniform curing in a single continuous exposure cycle, eliminating the time penalty associated with multiple exposures or iterative gray value adjustments
3Strength
If the radiation intensity is increased to improve green body hardness, then the hardness is improved, but delicate structures may break off due to excessive force
Solution Approach 1:
The oscillating mask creates spatially varying exposure patterns that adapt to local structure requirements. Delicate structures receive appropriately reduced intensity through the oscillation effect, while more robust areas receive sufficient energy for proper hardening, thereby achieving uniform green body hardness without causing damage to sensitive features
Solution Approach 2:
The periodic oscillation of the mask during exposure distributes the radiation energy more evenly across the structure. This periodic modulation prevents localized energy concentration that could cause excessive stress on delicate structures, while still delivering adequate total energy for achieving the required green body hardness
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 results in a more uniform and stable hardening depth, improved surface quality, and reduced manufacturing time, as it allows for the production of three-dimensional objects with smoother edges and precise dimensions using a single exposure mask, while maintaining the stability of both large and filigree structures.
Implementation Method 1
a radiation source (18) for generating the radiation... layer-by-layer solidification of a material (16) that can be solidified under the influence of radiation
Data Source
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AI summary
The invention relates to a method for producing a three-dimensional object (12) by solidifying layer by layer a material (16) that can be solidified by the action of radiation (14) using exposure masks (28), wherein at least one, preferably a single digital exposure mask is generated for forming each object layer to be solidified of the object (12) in a construction plane (22), by means of which exposure mask the radiation is projected selectively into the construction plane. According to the invention, the method is improved in that three-dimensional objects having an improved, smoother surface can be produced simply by exposing the construction plane (22) in an oscillating manner during an exposure time. The invention also relates to an improved exposure mask generation device and an improved device for producing a three-dimensional object.