Beam Director with Horizontal Axis Rotation
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Solution Overview
Problem
Conventional 3D printers with beam directors that rotate about a vertical axis require a second reflector to redirect the beam onto the work surface, leading to issues like increasing distances between light rays, beam energy absorption, and distortion as the beam moves away from the center, resulting in uneven energy distribution and beam shape changes.
Innovation Solution
A beam director with a rotating reflector aligned parallel to the work surface, using a light source and an actuator to maintain a constant angle, combined with correction methods such as f-theta lenses, Pulse Wide Modulation (PWM), Pulse Amplitude Modulation (PAM), or their combination to compensate for the tangent factor, ensuring equal distances and energy distribution across the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a reflector rotates about a vertical axis to scan the beam, then the beam can cover the work surface, but the distance between light rays increases and beam energy distribution becomes uneven
Solution Approach 1:
The patent inverts the conventional vertical axis rotation to horizontal axis rotation. The reflector rotates about a horizontal axis that is perpendicular to the beam direction and parallel to the work surface, which reverses the scanning geometry and eliminates the tangent factor effect that causes non-uniform energy distribution.
Solution Approach 2:
The patent changes the rotational axis orientation from vertical to horizontal, and positions the light source at a specific height above the work surface. This parameter change transforms the beam path geometry so that the beam remains perpendicular to the work surface throughout rotation, maintaining uniform energy distribution.
2Ease of operation
If a second reflector is added to redirect the beam onto the work surface, then the beam can be properly directed, but the device complexity increases
Solution Approach 1:
The patent extracts the second reflector from the system by repositioning the first reflector's rotation axis to be horizontal. This single reflector configuration replaces the conventional two-reflector system, simplifying the device while maintaining beam direction control capability.
Solution Approach 2:
The single reflector in the patent performs multiple functions: it scans the beam across the work surface and simultaneously maintains proper beam orientation perpendicular to the surface, eliminating the need for a separate second reflector that would be required in conventional vertical-axis systems.
3Area of stationary object
If the beam moves away from the center of the work surface, then the scanning area increases, but beam distortion and energy absorption increase
Solution Approach 1:
By inverting the rotation axis from vertical to horizontal, the patent eliminates the geometric distortion that occurs at the edges of the scanning area in conventional systems. The beam remains perpendicular to the work surface at all positions, preventing distortion and maintaining consistent quality across the entire scanning area.
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
The solution maintains consistent beam distances and energy distribution across the work surface, correcting for the tangent factor and preventing beam distortion, thereby ensuring uniform printing quality.
Implementation Method 1
a reflector configured to receive the beam of light from the light source along a rotational axis of the reflector for reflecting the beam onto a work surface at a constant angle to the rotational axis
Data Source
AI summary
A beam director, typically comprises a first mirror rotating about a longitudinal axis, with a reflective surface at an acute angle to the longitudinal axis, which enables a laser beam to be transmitted along the longitudinal axis and redirected onto a work surface, which is typically perpendicular to the longitudinal axis. A second stationary arcuate mirror segment may be used to reflect the beam along an arcuate path on the work surface. Previous beam director systems can be improved or simplified by: 1) elimination of the second mirror with a 90° reflection to the work surface; 2) fixing the Tangent factor when drawing/rendering/sintering/cutting using f-theta like lens; and 3) fixing the Tangent factor by controlling the amount and/or the duration of energy.