KR-20260063896-A - Method for polishing metal surfaces using laser pulse width control

KR20260063896AKR 20260063896 AKR20260063896 AKR 20260063896AKR-20260063896-A

Abstract

The method for polishing a metal surface through laser pulse width control of the present invention is a method for polishing a metal surface using a laser, and may include the step of setting laser conditions including the power of the laser irradiated according to the metal and the FWTM (Full width at tenth maximum) pulse width, and the step of polishing the metal surface by irradiating the laser adjusted to the set conditions onto the metal surface.

Inventors

김영국
조현호
김준호
정지훈
김대욱
차병철

Assignees

한국생산기술연구원

Dates

Publication Date: 20260507
Application Date: 20241031

Claims (7)

As a method of polishing a metal surface using a laser, A step of setting laser conditions including the power of the laser irradiated according to the metal and the FWTM (Full width at tenth maximum) pulse width; and A method for polishing a metal surface through laser pulse width control, comprising the step of polishing the metal surface by irradiating the metal surface with a laser adjusted to the above-set conditions.
In paragraph 1, A method for polishing a metal surface through laser pulse width control, wherein a crater formed by irradiating a single laser pulse onto the metal surface has a center height that increases as the FWTM pulse width increases.
In paragraph 1, A method for polishing a metal surface through laser pulse width control, wherein the surface polished by irradiating a continuous laser pulse onto the metal surface has a surface roughness (Ra) that decreases as the FWTM pulse width increases.
In paragraph 1, The step of setting the above laser conditions is, (a) a step of irradiating the metal surface with a single laser pulse to determine the range of laser power and FWTM pulse width; (b) a step of irradiating the metal surface with a continuous laser pulse to determine the range of laser power and FWTM pulse width; and (c) A method for polishing a metal surface through laser pulse width control, comprising the step of setting the overlapping range of the laser power and FWTM pulse width ranges identified in steps (a) and (b) above as the laser condition.
In paragraph 4, The step of (a) irradiating a single laser pulse to determine the range of laser power and FWTM pulse width is, A method for polishing a metal surface through laser pulse width control, wherein the center height of a crater formed on the metal surface by irradiating the single laser pulse is -1 to 1 μm, and the sum of the hole region (- value) and peak region (+ value) of the crater is -20 μm or more.
In paragraph 4, The step of determining the range of laser power and FWTM pulse width by irradiating (b) continuous laser pulses above is: A step of patterning the metal surface by irradiating the above continuous laser pulses; and A method for polishing a metal surface through laser pulse width control, which checks the surface roughness (Ra) of the patterned metal surface and identifies a range of laser power and FWTM pulse widths that have a surface roughness (Ra) lower than before laser irradiation.
In paragraph 1, A method for polishing a metal surface through laser pulse width control, wherein the metal is an aluminum alloy, the laser power is 130 to 150 W, and the FWTM pulse width is 600 ns or more, and the surface roughness (Ra) is 0.4 μm or less.

Description

Method for polishing metal surfaces using laser pulse width control The present invention relates to a method for polishing a metal surface using a laser, and more particularly to a method for polishing a metal surface through laser pulse width control, which controls the shape of a crater when processing a metal surface by adjusting the FWTM (Full width at tenth maximum) pulse width of the laser and controls the surface roughness when polishing the metal surface. When using chemicals and slurries for conventional metal surface polishing, manual sanding is required, and there are difficulties in polishing fine areas. On the other hand, lasers do not use abrasives or chemicals and can process complex shapes. In particular, laser surface polishing is suitable for automated equipment in processes such as 3D printing and can manufacture localized shapes ranging from mm to square meters. Laser polishing requires one process, whereas machine surface polishing requires one to three processes. Laser polishing requires less labor but has a high equipment cost, whereas machine surface polishing requires less equipment but has a high labor cost. When comparing lasers for metal surface polishing to mechanical surface polishing, the application of lasers in industrial settings has become a reality due to rising labor costs and reduced laser equipment prices. Laser surface polishing enables non-contact surface strengthening as needed, and allows for partial processing and polishing of complex shapes. Therefore, laser polishing technology for metal surfaces can be used for removing tool marks from mold surfaces or polishing the surfaces of 3D printed parts. Surface polishing is essential because tool marks from machining molds are transferred to injection-molded parts, and 3D printed parts require polishing due to their rough surfaces; thus, surface polishing technology that is advantageous for future automation can be applied. When lasers are applied to surface polishing, U-shaped craters are formed when the laser is incident on the metal surface. Consequently, there is a problem in that there are limitations to improving surface roughness after polishing. Therefore, research on a laser-based metal surface polishing method is necessary to solve the aforementioned problem. FIG. 1 is a conceptual diagram showing a metal surface flattening model using a laser according to one embodiment of the present invention. Figure 2 is a graph showing a normalized intensity curve. FIG. 3 is a graph showing the laser power over time of a laser used according to one embodiment of the present invention. FIG. 4 is a 2D, 3D image and shape profile of a crater according to the FWTM pulse width according to one embodiment of the present invention. FIG. 5 is a crater shape profile irradiated with a laser having a pulse width of 286 ns according to one embodiment of the present invention. FIG. 6 is a crater shape profile irradiated with a laser having an FWTM pulse width of 2020 ns according to one embodiment of the present invention. FIG. 7 is a crater image irradiated with lasers having FWTM pulse widths of 286 ns and 2020 ns with laser powers of 200 W and 140 W according to one embodiment of the present invention. FIG. 8 is a graph showing the crater center height according to the FWTM pulse width at 60~100% laser power according to one embodiment of the present invention. FIG. 9 is a graph showing the total crater area according to the FWTM pulse width at 60~100% laser power according to one embodiment of the present invention. FIG. 10 is a conceptual diagram of surface patterning by continuous laser pulses according to one embodiment of the present invention. FIG. 11 is a graph showing the crater surface roughness according to the FWTM pulse width at 60~100% laser power according to one embodiment of the present invention. FIG. 12 is an image showing the surface roughness before and after laser surface processing according to one embodiment of the present invention. Specific embodiments of the present invention will be described in detail below with reference to the drawings. However, the concept of the present invention is not limited to the presented embodiments. Those skilled in the art who understand the concept of the present invention may easily propose other inventions that are inferior or other embodiments included within the scope of the concept of the present invention by adding, changing, or deleting other components within the same scope of the concept, and such are also to be considered to be included within the scope of the concept of the present invention. Additionally, components with the same function within the scope of the same concept appearing in the drawings of each embodiment are described using the same reference numeral. A method for polishing a metal surface through laser pulse width control according to the present invention may include the step of setting laser conditions including the power of the laser irradia