Laser Machining Piercing Process Cooling
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Solution Overview
Problem
The existing laser machining method disclosed in Patent Literature 1 does not effectively inhibit self-burning during irradiation and has lower piercing efficiency and longer machining time due to difficulties in discharging molten metal and changes in machining point height during the piercing process.
Innovation Solution
A laser machining method involving a first piercing process forming a non-through hole, a cooling process, and a second piercing process to complete the hole, with controlled laser beam output, focal position, and side gas blow pressure settings to inhibit self-burning and enhance piercing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high output laser beam irradiation is performed to reduce piercing time, then piercing speed is improved, but self-burning occurs during irradiation
Solution Approach 1:
The piercing process is divided into multiple stages: a first piercing process forming a non-through hole, a cooling process, and a second piercing process completing the hole. This segmentation allows high-power irradiation to be used in the first process without causing self-burning, while the cooling process prevents self-burning before the second process begins.
Solution Approach 2:
The cooling process is performed as a preliminary action before the second piercing process. By cooling the workpiece between the first and second piercing processes, self-burning is prevented from occurring during subsequent high-power irradiation, enabling faster and safer piercing.
2Productivity
If continuous high-power irradiation is used to maintain piercing efficiency, then machining time is reduced, but molten metal discharge becomes difficult and machining point height changes
Solution Approach 1:
The laser irradiation is applied periodically with on-off cycles. The laser beam is irradiated during the first piercing process, then stopped during the cooling process, and re-irradiated during the second piercing process. This periodic action allows molten metal to be cooled and discharged between irradiation cycles, preventing discharge difficulties and machining point height changes.
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 method effectively inhibits self-burning and reduces the time required for piercing by optimizing laser beam parameters and side gas management throughout the machining process.
Implementation Method 1
forming a piercing hole by irradiating a workpiece with a laser beam
Implementation Method 2
forms the piercing hole in a short period of time by performing piercing that includes a first process of irradiating a workpiece with a beam
Implementation Method 3
cooling process of cooling the workpiece
Implementation Method 4
inhibits the oxidation/combustion reaction during piercing
Data Source
AI summary
A laser machining method includes a first piercing process of forming a non-through piercing hole extending from a top surface to a central portion of a workpiece; a workpiece cooling process; a second piercing process of making the piercing hole pierce to a bottom surface of the workpiece; and a workpiece cutting process. The second piercing process includes performing piercing by irradiating the workpiece with a laser beam while changing the output of the laser beam from a second output value to a third output value, which is smaller than the first output value and larger than the second output value, the focal position from a first in-focus position to a second in-focus position having a larger in-focus amount than the first in-focus position, and the depth of focus from a second depth deeper than a first depth to a third depth deeper than the second depth.