CN116372396B - Laser drilling and boring hole-making method for carbon fiber composite material - Google Patents

Abstract

The present invention discloses a method for laser drilling and boring of carbon fiber composite materials. First, a high-energy laser is used to drill holes in CFRP at high speed, and then a low-energy short-pulse laser is used to finish the edge of the hole to remove rough edge burrs, sawtooth ripples and heat-affected zones. The method of the present invention takes into account both the high efficiency of "drilling" and the high quality of "boring", improves the quality of the section, and realizes high-quality and high-efficiency hole making of CFRP.

Description

A method for laser drilling and boring holes in carbon fiber composite materials

Technical Field

The invention relates to a method for opening holes in a carbon fiber composite material (CFRP).

Background technique

Carbon fiber composites (CFRP) have excellent thermal properties such as good fatigue resistance, high specific strength, and good heat resistance, and have been widely used in the fields of aviation and aerospace. As the main load-bearing component, the mechanical connection between CFRP plates requires a large number of assembly holes. However, with the continuous improvement of the lightweight requirements for high-end equipment in the fields of aviation and aerospace, the mechanical properties of the raw materials of CFRP components have been greatly improved. Traditional mechanical hole making has many hole making processes, burrs around the holes, and interlayer tearing, which affect the fatigue performance and service life of CFRP. With the development of laser manufacturing technology, laser processing has obvious advantages in CFRP hole making, such as less fiber damage, less interlayer tearing, and a high degree of automation. However, laser hole making still faces the problems of difficult control of the heat affected zone and low efficiency.

Summary of the invention

Purpose of the invention: In view of the above-mentioned prior art, a method for laser drilling and boring of carbon fiber composite materials is proposed to achieve high-quality and high-efficiency hole making of CFRP.

Technical solution: A method for laser drilling and boring of carbon fiber composite materials, comprising: the first step of using high-energy laser beam high-speed rotary cutting technology to quickly drill holes on CFRP; the second step of using low-energy laser beam finishing technology to bore the hole wall to improve the quality of the hole wall.

Furthermore, in the first step, the high-speed rotary cutting technology is that the laser beam rotates and cuts along the edge of the hole under the action of the scanning galvanometer, and the laser beam spins at high speed, the spinning radius is r, the spinning step length is d, and the cutting aperture is R.

Furthermore, the spin radius r is set to (0.1-0.5)×h, h is a preset depth of the drilling hole, and the spin step length d is set to (0.5-0.9)×r.

Furthermore, the high-energy laser beam is a millisecond, nanosecond, picosecond or femtosecond laser with a power greater than 30W, a wavelength of 1064nm, 532nm or 355nm, and a laser beam peeling speed greater than or equal to 2000mm/s.

Furthermore, the laser beam finishing technology in the second step is to perform high-speed scanning of the laser beam along the hole wall after drilling in the first step to remove the serrated lines and heat-affected zone generated on the hole wall in the first step. The width of the laser scanning filling in the second step is consistent with the height of the serrated corrugations, which is Δd. The inner diameter and outer diameter of the scanning circle are R1 and R2, respectively, and the three satisfy Δd=R2-R1.

Furthermore, the number n of filling lines within the filling width Δd is determined by the spot diameter D after the laser beam is focused, and the three satisfy 2×Δd＝(n+1)×D.

Furthermore, the low-energy laser beam is a nanosecond, picosecond or femtosecond laser with a power less than 15 W, a wavelength of 1064 nm, 532 nm or 355 nm, and a scanning speed of the laser beam is greater than or equal to 2000 mm/s.

Beneficial effects: In order to achieve high-quality and high-efficiency hole making in CFRP, the present invention proposes a method for laser drilling and boring of carbon fiber composite materials, which takes into account both the high efficiency of "drilling" and the high quality of "boring". First, high-energy laser is used to drill holes in CFRP at high speed, and then low-energy short-pulse laser is used to finish the edge of the hole, remove rough edge burrs, sawtooth ripples and heat-affected zones, and improve the quality of the section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a CFRP laser hole making method according to the present invention;

FIG2 is a diagram showing the evolution of the pore wall morphology in the method of the present invention;

FIG. 3 is a hole pattern diagram in the embodiment.

Detailed ways

The present invention will be further explained below in conjunction with the accompanying drawings.

A method for laser drilling and boring of carbon fiber composite materials comprises the following specific steps:

Step 1: As shown in Figure 1a, a through hole is made in CFRP by laser. The thickness of CFRP material is h = 5mm. The radius of the hole to be processed R = 5mm is set by scanning galvanometer, and the parameters of high-energy laser beam high-speed rotary cutting are: spin radius r = 1mm, spin step d = 0.5mm, scan times 200 times, and rotary cutting speed 2000mm/s. The laser wavelength used for rotary drilling is 532nm, the laser power is 35w, and the pulse width and frequency are 1μs and 60KHz respectively.

Step 2: Start the laser processing system and use a high-power density laser beam to irradiate the drilling area defined on the surface of the carbon fiber composite material, so that the carbon fiber composite material is rapidly heated to the vaporization temperature and evaporates to form holes. The carbon fiber composite material is initially pierced. At this time, the hole wall has serrated lines and a heat-affected zone, as shown in Figure 2a and Figure 3a, where the height of the serrated lines is Δd=0.2mm, and the size of the heat-affected zone is about 179.5μm, which is specifically determined by the self-selected radius r and the spin step d of the laser beam high-speed rotary cutting.

Step 3: As shown in b of Figure 1, the path and process parameters of laser boring are set by scanning galvanometer, the inner diameter of the scanning circle R1 = 4.9mm, the outer diameter of the scanning circle R2 = 5.1mm, the width of scanning filling Δd = 0.2mm, the spot diameter after laser focusing D = 20μm, and the number of filling lines n = 19. The number of scans is set to 200 times, and the scanning speed is 3000mm/s. The laser wavelength is 532nm, the power is 15w, and the pulse width and frequency are set to 100ns and 35KHz respectively.

Step 4: Start the laser processing system, and the laser beam scans along the hole wall at high speed to quickly remove the serrations and heat-affected zone of the hole wall, forming a smooth hole wall without ripples and heat-affected zones, as shown in Figure 2b and Figure 3b, and the hole wall roughness reaches Ra = 3.838μm.

In the above embodiments, the high-energy laser beam can also select a millisecond, nanosecond, picosecond, or femtosecond laser with a power greater than 30W, and a wavelength of 1064nm, 532nm, or 355nm. The low-energy laser beam can also select a nanosecond, picosecond, or femtosecond laser with a power less than 15W, and a wavelength of 1064nm, 532nm, or 355nm. In step 1, the spin radius r and the spin step d can be set according to the thickness h of the composite material, and the spin radius r is set to (0.1-0.5)×h, and the spin step d is set to (0.5-0.9)×r.

The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims (4)

1. A method for laser drilling and boring of carbon fiber composite materials, characterized in that it comprises: a first step of using high-energy laser beam high-speed rotary cutting technology to quickly drill holes on CFRP; a second step of using low-energy laser beam finishing technology to bore the hole wall to improve the quality of the hole wall; in the second step, the laser beam finishing technology is to perform high-speed scanning of the laser beam along the hole wall after drilling in the first step, and the width of the laser scanning filling in the second step is the height Δd of the toothed lines generated on the hole wall in the first step, the inner diameter and the outer diameter of the scanning circle are R1 and R2 respectively, and the three satisfy Δd=R2-R1; the number of filling lines n within the filling width Δd is determined by the spot diameter D after the laser beam is focused, and the three satisfy 2×Δd=(n+1)×D; the low-energy laser beam is a nanosecond, picosecond, or femtosecond laser with a power less than 15W, a wavelength of 1064nm, 532nm, or 355nm, and a scanning speed of the laser beam is greater than or equal to 2000mm/s. 2. A method for laser drilling and boring holes in carbon fiber composite materials according to claim 1, characterized in that in the first step, the high-speed rotary cutting technology is that the laser beam rotates and cuts along the edge of the hole under the action of a scanning galvanometer, and the laser beam spins at high speed, the spinning radius is r, the spinning step length is d, and the cutting aperture is R. 3. A carbon fiber composite material laser drilling and boring method according to claim 2, characterized in that the spin radius r is set to (0.1~0.5)×h, h is the preset depth of the drilling, and the spin step d is set to (0.5~0.9)×r. 4. A method for laser drilling and boring of carbon fiber composite materials according to claim 2, characterized in that the high-energy laser beam is a millisecond, nanosecond, picosecond, or femtosecond laser with a power greater than 30 W, a wavelength of 1064 nm, 532 nm, or 355 nm, and a laser beam peeling speed greater than or equal to 2000 mm/s.