Rotating Polygon Mirror for Uniform Energy Distribution in Additive Manufacturing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In additive manufacturing, existing energy delivery systems often result in non-uniform energy distribution across layers due to acceleration and deceleration of reflective members, leading to inconsistent surface quality and increased post-processing requirements.
Innovation Solution
A rotatable reflective member with multiple facets, in conjunction with a light source and actuator, delivers energy uniformly across layers by continuously sweeping a light beam along a path with minimal acceleration and deceleration, ensuring consistent energy distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional energy delivery systems use reflective members that accelerate and decelerate to position the light beam, then the system can deliver energy to different locations, but the energy distribution becomes non-uniform and surface quality deteriorates
Solution Approach 1:
The patent applies continuous rotation of the polygonal mirror to sweep the light beam across the build platform without acceleration and deceleration cycles. The mirror rotates continuously at constant velocity, and the light beam is modulated on and off to create the desired pattern, eliminating the start-stop motion that causes non-uniform energy distribution and surface quality issues.
Solution Approach 2:
The patent uses periodic modulation of the light source in synchronization with the rotating polygonal mirror facets to deliver energy at specific locations. As each facet passes through the light beam path, the light is selectively activated to deposit energy at the corresponding location, creating a periodic energy delivery pattern that ensures uniformity.
2Area of stationary object
If reflective members frequently change direction to cover the entire build area, then complete coverage is achieved, but acceleration and deceleration increase processing time
Solution Approach 1:
The polygonal mirror rotates continuously without stopping or reversing direction, maintaining constant angular velocity throughout the scanning process. This eliminates acceleration and deceleration time at each position change, allowing the system to cover the entire build platform area while maximizing processing throughput.
Solution Approach 2:
The system dynamically sweeps the light beam across the build platform by rotating the polygonal mirror, creating continuous motion coverage. The mirror's rotation dynamically positions different facets to scan various regions of the build platform, achieving complete area coverage through continuous dynamic motion rather than static positioning.
3Manufacturing precision
If the light beam is delivered in a raster pattern with frequent direction changes, then complete layer coverage is achieved, but surface deformations increase due to non-uniform energy delivery
Solution Approach 1:
The continuous rotation of the polygonal mirror ensures that the light beam sweeps across each layer with uniform velocity, delivering consistent energy distribution across the entire layer. This eliminates the acceleration and deceleration-induced non-uniformity that causes surface deformations, while the selective light modulation ensures complete layer coverage through the raster pattern.
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 enhances the uniformity of energy delivery, reducing surface deformations and the need for post-processing, resulting in improved surface quality and increased throughput.
Implementation Method 1
a reflective member that has a plurality of reflective facets. The reflective member is positioned in a path of the light beam to receive the light beam and redirect the light beam toward the top surface of the platform
Implementation Method 2
a light source to emit a light beam... The light source may be a laser configured to emit the light beam toward the reflective member
Implementation Method 3
deliver energy to an uppermost layer of the layers of feed material to fuse the feed material
Data Source
AI summary
An additive manufacturing apparatus includes a platform, a dispenser to dispense a plurality of layers of feed material on a top surface of the platform, and an energy delivery assembly. The energy delivery assembly includes a light source to emit one or more light beams, a first reflective member having a plurality of reflective facets, and at least one second reflective member. The first reflective member is rotatable such that sequential facets sweep the light beam sequentially along a path on the uppermost layer. The at least one second reflective member is movable such that the at least one second reflective surface is repositionable to receive at least one of the at least one light beam and redirect the at least one of at least one light beam along a two-dimensional path on the uppermost layer.