Laser Process Head Optical Unit Motion With Symmetric Magnetic Actuators
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Solution Overview
Problem
Existing systems for moving focusing lenses in laser processes face challenges in achieving rapid and precise focusing movements while minimizing torsion moments and ensuring precise alignment.
Innovation Solution
A device with symmetrically arranged magnetic actuators and guides, each with a cylindrical electromagnetic stator and piston, provides balanced thrust without generating torsion moments, using series-connected electro-conductive coils for precise movement control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a galvanometer is used to move the optical unit, then the device complexity is reduced, but the manufacturing precision deteriorates due to inertia and back EMF effects
Solution Approach 1:
The system is divided into two independent control loops: an outer position control loop that receives target position signals and a inner current control loop that directly controls the galvanometer coil current. This segmentation allows the position controller to operate without being affected by galvanometer back EMF and inertia, thereby maintaining positioning precision while using a galvanometer mechanism.
Solution Approach 2:
A current controller is introduced as an intermediary between the position controller and the galvanometer. This current controller generates the coil current based on position error signals and actively compensates for the galvanometer's inertial and back EMF effects, enabling precise positioning despite the galvanometer's inherent limitations.
2Length of moving object
If the scanner is positioned close to the exit face of the laser source, then the length of the optical unit is reduced, but the manufacturing precision deteriorates due to space constraints affecting movement accuracy
Solution Approach 1:
The patent replaces traditional mechanical positioning systems with a dual-loop control system (position control + current control) that electronically compensates for mechanical limitations. This allows the optical unit to be positioned close to the laser source exit face while maintaining precision through active control rather than relying solely on mechanical design.
3Stability of the object's composition
If the optical unit is moved to compensate for beam deviation, then the beam pointing stability is improved, but the speed of response deteriorates due to mechanical movement limitations
Solution Approach 1:
The system implements dynamic control by continuously adjusting the galvanometer coil current based on real-time position error signals from the dual-loop control system. This dynamic current adjustment enables the optical unit to rapidly respond to and compensate for beam deviations, improving both response speed and pointing stability simultaneously.
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
Enables rapid and precise focusing movements with minimal torsion, maintaining optical axis alignment and reducing thermal stress through symmetric actuator configuration and thermal management.
Implementation Method 1
the inertia of the galvanometer and the back EMF generated by rotation of the galvanometer in the presence of a magnetic field
Implementation Method 2
the inertia of the galvanometer and the back EMF generated by rotation of the galvanometer in the presence of a magnetic field
Implementation Method 3
generating a control signal which is proportional to a position error between a target position and a current position of the optical unit
Implementation Method 4
a laser source (202) configured to emit a laser beam (203)
Implementation Method 5
a movable optical unit (204) configured to reflect the laser beam
Data Source
Figure 1
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Figure 3
AI summary
The device comprises a body (3) and an optical unit (5), movable with respect to the body (3) along a translation axis (Z). The optical assembly houses the focusing lens (7) with the optical axis (A- A) of the focusing lens (7) parallel to the translation axis (Z) of the optical unit (5). The optical unit comprises a slide (11) which slides along a linear guide system parallel to the translation axis (Z). The device further comprises a magnetic actuator (23) comprising an electromagnetic stator (25) integral with the body (3) and a magnetic piston (27) constrained to the optical unit (5). The magnetic piston (27) is housed in a seat (24) formed in the electromagnetic stator (25) and movable along a motion axis (B-B) parallel to the translation axis (Z) of the optical unit (5).