Laser Beam Vibration for High-Speed Stainless Steel Sheet Cutting
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Solution Overview
Problem
Laser machining of stainless steel sheet metal with a thickness of 3 mm or more using a 1 µm laser beam often results in narrow kerf widths, leading to machining defects due to insufficient molten metal discharge, and increasing laser power is not energy-efficient.
Innovation Solution
A laser machining apparatus and method that vibrates the laser beam in a parallel direction with the cutting advancing direction, using a specific amplitude range and frequency to maintain molten metal viscosity and facilitate efficient discharge, allowing for high-speed cutting without defocusing the beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the laser beam is focused to a narrow kerf width, then the beam energy concentration is improved, but the molten metal discharge becomes insufficient causing machining defects
Solution Approach 1:
The patent applies beam vibration in the parallel direction to periodically modulate the energy distribution within the kerf. This vibration prevents excessive heat accumulation that would increase molten metal viscosity, thereby maintaining discharge capability while preserving narrow kerf width and high energy concentration.
Solution Approach 2:
The laser beam applies periodic action through controlled vibration at specific frequencies. This periodic modulation of energy input prevents continuous heat buildup, maintaining molten metal流动性 (fluidity) and ensuring consistent discharge throughout the cutting process.
2Reliability
If the focus point is defocused to widen the kerf width, then the molten metal discharge is improved, but the energy density decreases reducing cutting velocity
Solution Approach 1:
Instead of defocusing the beam to widen the kerf, the patent vibrates the focused beam in the parallel direction. This maintains the high energy density of the focused beam while preventing excessive heat accumulation, thus preserving both cutting velocity and molten metal discharge capability.
Solution Approach 2:
The patent changes the temporal parameter of energy input by introducing vibration frequency and amplitude. This allows the system to maintain high energy density through focused beams while controlling heat accumulation through periodic modulation, achieving both high productivity and reliable discharge.
3Productivity
If the laser power is increased to increase cutting velocity, then the productivity is improved, but the energy consumption increases which is not preferable
Solution Approach 1:
The patent uses beam vibration to optimize the utilization of existing laser power. By preventing excessive heat accumulation and maintaining molten metal fluidity, the system achieves high cutting velocity without needing to increase power input, thereby improving productivity while controlling energy consumption.
Solution Approach 2:
The patent implements feedback control by monitoring cutting conditions and adjusting vibration parameters accordingly. This ensures optimal energy utilization by adapting the vibration frequency and amplitude to maintain efficient cutting throughout the process, maximizing productivity per unit of energy consumed.
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 high-speed cutting of stainless steel with good surface quality by maintaining low molten metal viscosity and efficient discharge, even at thicker plate thicknesses, without the need for increased laser power.
Implementation Method 1
a laser oscillator emitting a laser beam in a band of 1 µm... the sheet metal is irradiated with the laser beam... the laser beam with which the sheet metal is irradiated
Implementation Method 2
a beam vibrating mechanism configured to vibrate the laser beam in a parallel direction with a cutting advancing direction of the sheet metal... vibrating the laser beam in a parallel direction with a cutting advancing direction of the sheet metal within a kerf width of the sheet metal
Data Source
Figure 1
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AI summary
A machining head (35) emits a laser beam for cutting sheet metal (W) of stainless steel. A moving mechanism moves the machining head (35) relatively to a surface of the sheet metal (W). A beam vibrating mechanism vibrates a laser beam in a parallel direction with a cutting advancing direction of the sheet metal (W). In a machining condition database (70), a single specific vibration frequency at which cutting of the sheet metal (W) is possible is set to a maximum moving velocity at which cutting of the sheet metal (W) is possible, and a plurality of vibration frequencies from a maximum frequency to a minimum frequency at which cutting of the sheet metal (W) is possible are set to a moving velocity more than or equal to a minimum moving velocity and less than the maximum moving velocity at which cutting of the sheet metal (W) is possible. An NC device (50) controls the beam vibrating mechanism to vibrate the laser beam at a vibration frequency set in the machining condition database (70).