Laser Cutting Beam Shape for Burr-Resistant Kerf Edges
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Solution Overview
Problem
Laser cutting methods using solid-state lasers often result in burr formation and increased surface roughness due to molten material sticking to the cutting flanks, as the temperature of the molten material decreases behind the cutting front, increasing its viscosity and causing it to stick to the workpiece and cutting flanks.
Innovation Solution
A method and apparatus for laser cutting that employs a laser beam with a non-circular cross-section and a cutting beam contour that adjoins the cutting flanks at an angle, preventing molten material from flowing onto the flanks by creating a discontinuous transition, and using a cutting gas to evacuate the material close to the cutting front vertex, thereby reducing burr formation and improving cutting edge quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If molten material is evacuated at some distance in the trailing region behind the cutting front, then the laser beam can maintain cutting temperature at the cutting front, but the temperature of the molten material decreases as distance from the cutting front increases, causing increased viscosity and burr formation
Solution Approach 1:
The patent introduces a second laser beam (trailing beam) that acts in a different spatial dimension relative to the cutting front. While the leading beam maintains the cutting front temperature, the trailing beam follows behind to reheat the molten material in the evacuation region, preventing temperature drop and viscosity increase that would cause burrs.
Solution Approach 2:
The patent changes the thermal parameters by introducing a trailing laser beam that provides additional heating to the molten material in the evacuation region. This maintains the temperature of the molten material even at distances from the cutting front, preventing the viscosity increase that leads to burr formation and poor cutting edge quality.
2Ease of operation
If molten material is evacuated in a pulsed manner at some distance behind the cutting front, then the cutting process can be controlled, but molten material becomes stuck to the cutting flanks and solidifies, increasing surface roughness
Solution Approach 1:
The trailing laser beam acts as an intermediary heating source between the cutting front and the evacuation region. It provides continuous thermal energy to the molten material in the trailing region, preventing it from solidifying on the cutting flanks and reducing surface roughness while maintaining process control.
3Device complexity
If a conventional circular laser beam is used for cutting, then the equipment is simple, but the cutting front does not efficiently prevent molten material from flowing onto the cutting flanks, resulting in burr formation
Solution Approach 1:
The patent employs two laser beams with different functions positioned asymmetrically relative to the cutting front - a leading beam for primary cutting and a trailing beam for reheating the evacuation region. This asymmetric configuration optimizes the prevention of molten material overflow onto cutting flanks, reducing burrs and improving cutting edge quality.
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 angled transition between the cutting front and flanks effectively prevents molten material from sticking, reducing burr formation and surface roughness, leading to improved cutting quality and removability of cut parts.
Implementation Method 1
material is melted on the workpiece at a cutting front extending between the cutting flanks
Implementation Method 2
a laser beam is guided over the workpiece in a cutting direction so that a cutting kerf having two cutting flanks is produced
Implementation Method 3
evacuation is frequently effected in a pulsed manner
Implementation Method 4
The laser beam has a non-circular cross section and, at a front of the laser beam in the cutting direction, a continuous cutting beam contour corresponding to the cutting front
Data Source
AI summary
A method for laser cutting a workpiece includes the steps of guiding a laser beam over the workpiece in a cutting direction so as to produce a cutting kerf with two cutting flanks and melting material on the workpiece at a cutting front that extends between the cutting flanks and adjoins at least one of the cutting flanks at an angle. The laser beam has a non-circular cross section and, at a front of the laser beam in the cutting direction, a continuous cutting beam contour corresponding to the cutting front.