CN106338337A - Apparatus for carrying out on-line monitoring on punching quality during laser punching and monitoring method thereof - Google Patents

Abstract

The invention discloses an apparatus for carrying out on-line monitoring on a punching quality during laser punching and a monitoring method thereof. The apparatus is composed of a pulse laser, a beam shaping system, a workpiece, a high-sensitivity microphone, an oscilloscope, data lines and an industrial personal computer. The industrial personal computer is connected with the pulse laser and the oscilloscope by data lines respectively; the high-sensitivity microphone is connected with the oscilloscope by a data line; and the pulse laser faces the beam shaping system. When the pulse laser works, a laser beam emitted by the pulse laser is shaped by the beam shaping system and radiates the workpiece. According to the invention, counting of the laser pulse number needed by the punching process is carried out; and the counted laser pulse number is compared with a standard sample, thereby realizing real-time monitoring of the punching quality. With the apparatus and method, the punching quality can be determined; the cost is low; and the precision is high.

Description

Device and monitoring method for online monitoring of drilling quality in laser drilling

technical field

The invention relates to the technical field of laser processing, in particular to a device for online monitoring of drilling quality in laser drilling and a monitoring method thereof.

Background technique

Laser drilling technology is one of the earliest application technologies of laser in the field of material processing. Compared with other drilling methods, laser drilling has significant advantages such as large hole depth-to-diameter ratio, no contact, no tool loss, fast processing speed, small surface deformation, and can process various materials. It can well meet the needs of modern industrial products. Processing requirements are widely used in key components of high-precision cutting-edge products such as aerospace, electronic instruments, and medical equipment. For example, laser processing technology is used to process up to 104 cooling holes on aero-engines.

During the laser drilling process, the high-energy pulsed laser is focused on the surface of the workpiece to heat, melt or even vaporize the material, and then the molten material is extruded out of the hole under the joint action of the recoil pressure of the rapid expansion of the metal vapor and the pressure of the high-pressure auxiliary gas. , the subsequent pulsed laser continues the above process, and the material is continuously removed until a blind hole or a through hole is formed.

When laser drilling a thick workpiece, changing the laser drilling parameters such as laser power, laser frequency, laser pulse width, spot size, defocus, drilling time, auxiliary gas, etc. will affect the quality of laser drilling , Improper punching parameters will lead to irregular hole diameters, and even drum-shaped deformed holes and other defects. However, for the evaluation of the quality of laser drilling, the conventional method is usually to cut the hole for inspection, which is obviously not suitable for inspection of industrial products. Therefore, online monitoring of the drilling quality is necessary.

Contents of the invention

The purpose of the present invention is to provide a device for online monitoring of the drilling quality in laser drilling and a monitoring method thereof. By obtaining the characteristics of the voiceprint in the drilling process and analyzing and comparing them, the entire laser drilling process can be monitored and evaluated. Punch quality.

A technical solution of the present invention is: a device for online monitoring of drilling quality in laser drilling, including a pulse laser, a beam shaping system, a workpiece, a high-sensitivity microphone, an oscilloscope, a data line, and an industrial computer. The industrial computer passes The data lines are respectively connected to the pulse laser and the oscilloscope, the high-sensitivity microphone is connected to the oscilloscope through the data line, and the pulse laser is facing the beam shaping system. When the pulse laser is working, the laser beam emitted by the pulse laser is radiated after being shaped by the beam shaping system. to the workpiece.

Another technical solution of the present invention is: a method for online monitoring of drilling quality in laser drilling, comprising the following steps:

Step 1: Obtain optimized laser drilling process parameters, obtain process parameters with high drilling efficiency, good hole section quality, and meet processing requirements, and use the optimized drilling parameters to perform laser drilling on the workpiece until the hole is pierced. The audio signal of the whole drilling process is obtained through a high-sensitivity microphone, and these audio signals are transmitted to the oscilloscope through the data line. After the audio signal is filtered by the oscilloscope, the voiceprint characteristics of the laser drilling process are obtained, and the voiceprint characteristics are stored in the industrial computer. middle;

Step 2: Repeat step 1 to obtain 10 groups of voiceprint samples, count the number of laser pulses required to perforate each hole through the voiceprint samples, remove the highest pulse number and the lowest pulse number in the count, and take the remaining 8 groups The average number N of laser pulses required for voiceprint samples.

Step 3: Use the optimized laser drilling parameters obtained in step 1 to perform laser drilling on the workpiece, and obtain the audio signal of the entire drilling process through a high-sensitivity microphone, and transmit these audio signals to the oscilloscope through the data line, and the audio signal passes through the oscilloscope After filtering, the voiceprint characteristics of the entire laser drilling process are obtained, and the number of laser pulses required to punch through the hole is counted N1 through the voiceprint sample. If ξ1*N≤N1≤ξ2*N, the quality of the hole is judged Qualified, otherwise, it is judged that the quality of the hole is unqualified, where ξ1 and ξ2 are quality coefficients, 0.95<ξ1<1, 1<ξ2<1.1. The thickness is different, the material of the workpiece is different, and the quality factor is also different.

The working principle of the present invention is as follows: use pulsed laser to punch holes in workpieces with larger thickness. For workpieces with the same thickness, when the punching quality is stable, the number of laser pulses required is basically the same. If the number of laser pulses exceeds a certain value or is less than a certain value, it is considered that there is a problem in the drilling process. If the number of laser pulses required for drilling is too small, it is likely that the drilling process ends early due to the blasting. However, the hole diameter will be very large, and the punching quality does not meet the requirements; if the number of laser pulses required for punching holes is too large, it is likely that the molten metal cannot be discharged smoothly during the punching process, which will cause "drum holes", " The occurrence of defective holes such as crooked holes.

The advantages of the present invention are: the present invention can monitor the perforation quality in real time by counting the number of laser pulses required in the perforation process and comparing it with the standard sample; using the present invention to determine the perforation quality has low cost and high precision .

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment:

Fig. 1 is a schematic diagram of the structure of the present invention.

Among them: 1 pulse laser; 2 laser beam; 3 beam shaping system; 4 workpiece; 5 high-sensitivity microphone; 6 oscilloscope; 7 data line; 8 industrial computer.

detailed description

An embodiment of a device for online monitoring of drilling quality in laser drilling: as shown in Figure 1, it includes a pulsed laser 1, a beam shaping system 3, a workpiece 4, a high-sensitivity microphone 5, an oscilloscope 6, a data line 7 and an industrial control machine 8, the industrial computer 8 is respectively connected to the pulse laser 1 and the oscilloscope 6 through the data line 7, the high-sensitivity microphone 5 is connected to the oscilloscope 6 through the data line 7, the pulse laser 1 is facing the beam shaping system 3, and the pulse When the laser 1 is working, the laser beam 2 emitted by the pulsed laser 1 is irradiated to the workpiece 4 after being shaped by the beam shaping system 3 . The invention can quickly and effectively detect the laser drilling quality, and can be applied to online detection of the laser drilling quality.

A specific embodiment of a method for online monitoring of drilling quality in laser drilling:

In this embodiment, the workpiece 4 is made of TC4 titanium alloy with a thickness of 3 mm; the technical parameters of the pulse laser 1 are as follows: the pulse width is adjustable from 100 ns to 500 ms, the maximum repetition rate is 10 MHz, the maximum power is 400 W, and the light intensity distribution is Gaussian. The goal of this embodiment is to obtain a through hole with a diameter of 200 μm on the TC4 titanium alloy workpiece 4. For a 3 mm thick TC4 titanium alloy, the quality coefficients ξ1=0.99 and ξ2=1.02.

Implement the concrete steps of the present invention as follows:

Step 1: The optimized laser drilling parameters are as follows: the pulse width is 100 μs, the repetition frequency is 2000 Hz, the power is 400 W, and oxygen is assisted. Use these parameters to perform laser drilling on the TC4 titanium alloy workpiece 4 until the hole is pierced. The microphone 5 acquires the audio signals of the entire drilling process, and transmits these audio signals to the oscilloscope 6 through the data line 7. After the audio signals are filtered by the oscilloscope 6, the voiceprint characteristics of the laser drilling process are obtained, and the voiceprint characteristics are stored in the industrial control system. Machine 8.

Step 2: Repeat step 1 to obtain 10 groups of voiceprint samples, and count the number of laser pulses required to penetrate each hole through the voiceprint samples. The pulses required for these 10 groups of voiceprint samples to penetrate TC4 titanium alloy workpiece 4 The numbers are: 7085, 7114, 7093, 7155, 7095, 7091, 7056, 7107, 7102, 7097, remove the highest pulse number 7155 and the lowest pulse number 7056 in the count, and take the remaining 8 groups of voiceprint samples. The average value of the number of pulses is 7098, and the qualified range of punching quality is 7027-7240.

Step 3: Using a pulse width of 100 μs, a repetition frequency of 2000 Hz, a power of 400 W, and oxygen assistance, laser drilling is performed on the TC4 titanium alloy workpiece 4, and the audio signals of the entire drilling process are obtained through the high-sensitivity microphone 5, and these audio signals are The audio signal is transmitted to the oscilloscope 6 through the data line 7. After the audio signal is filtered by the oscilloscope 6, the voiceprint characteristics of the entire laser drilling process are obtained, and the number of laser pulses required to punch through the hole is counted through the voiceprint sample, and the hole is punched. The required number of pulses is 7147, and if it is between 7027 and 7240, it can be considered that the quality of the hole is qualified. After the cut hole inspection, the quality of the hole meets the requirements.

A second specific embodiment of a method for online monitoring of drilling quality in laser drilling:

In this embodiment, the workpiece 4 is made of TC4 titanium alloy with a thickness of 3 mm; the technical parameters of the pulse laser 1 are as follows: the pulse width is adjustable from 100 ns to 500 ms, the maximum repetition rate is 10 MHz, the maximum power is 400 W, and the light intensity distribution is Gaussian. The goal of this embodiment is to obtain a through hole with a diameter of 200 μm on the TC4 titanium alloy workpiece 4. For a 3 mm thick TC4 titanium alloy, the quality coefficients ξ1=0.99 and ξ2=1.02.

The specific steps of implementing this embodiment are as follows:

Step 1, the optimized laser drilling parameters are as follows: the pulse width is 100 μs, the repetition frequency is 2000 Hz, the power is 400 W, and oxygen is assisted. Use these parameters to perform laser drilling on the TC4 titanium alloy workpiece 4 until the hole is pierced. The microphone 5 acquires the audio signals of the entire drilling process, and transmits these audio signals to the oscilloscope 6 through the data line 7. After the audio signals are filtered by the oscilloscope 6, the voiceprint characteristics of the laser drilling process are obtained, and the voiceprint characteristics are stored in the industrial control system. Machine 8.

Step 2, repeat step 1 to obtain 10 groups of voiceprint samples, count the number of laser pulses required to penetrate each hole through the voiceprint samples, and the pulses required for these 10 groups of voiceprint samples to penetrate TC4 titanium alloy workpiece 4 The numbers are: 7085, 7114, 7093, 7155, 7095, 7091, 7056, 7107, 7102, 7097, remove the highest pulse number 7155 and the lowest pulse number 7056 in the count, and take the remaining 8 groups of voiceprint samples. The average value of the number of pulses is 7098, and the qualified range of punching quality is 7027-7240.

Step 3: Using a pulse width of 100 μs, a repetition frequency of 2000 Hz, a power of 400 W, and oxygen assistance, laser drilling is performed on the TC4 titanium alloy workpiece 4, and the audio signals of the entire drilling process are obtained through the high-sensitivity microphone 5, and these audio signals are The audio signal is transmitted to the oscilloscope 6 through the data line 7. After the audio signal is filtered by the oscilloscope 6, the voiceprint characteristics of the entire laser drilling process are obtained, and the number of laser pulses required to punch through the hole is counted through the voiceprint sample, and the hole is punched. The required number of pulses is 7347. If the number of pulses is outside 7027~7240, it is considered that the quality of the hole is unqualified. After the hole inspection, it is found that the hole has a "crooked hole" defect.

To sum up, the present invention can quickly and effectively detect the quality of laser drilling, and solves the problem of difficulty in detecting the quality of holes in laser drilling.

The above are only specific application examples of the present invention, and do not constitute any limitation to the protection scope of the present invention. In addition to the above-mentioned embodiments, the present invention can also have other embodiments. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims (3)

1. in a kind of laser boring on-line monitoring drilling quality device it is characterised in that: include pulse laser (1), light beam Orthopedic systems (3), workpiece (4), high sensitivity microphone (5), oscillograph (6), data wire (7) and industrial computer (8), described industry control Machine (8) is connected with pulse laser (1) and oscillograph (6) respectively by data wire (7), and described high sensitivity microphone (5) is led to Cross data wire (7) to be connected with oscillograph (6), described pulse laser (1) is just to beam shaping system (3), pulse laser (1) During work, laser beam (2) that pulse laser (1) sends after beam shaping system (3) shaping irradiation to workpiece (4).

2. in a kind of laser boring on-line monitoring drilling quality method, comprise the following steps:

Step one: obtain the laser boring technological parameter optimizing, obtain perforating efficiency height, pore cross section quality is good, meeting processing will The technological parameter asked, and using the downhole parameter optimizing, laser boring is carried out to workpiece (4), until this hole is punched, by Gao Ling Sensitivity microphone (5) obtains the audio signal of whole drill process, and these audio signals are transferred to by data wire (7) show Ripple device (6), audio signal, after oscillograph (6) filtering, obtains the vocal print feature of laser drilling process, vocal print feature is stored in In industrial computer (8)；

Step 2: repeat step one, obtain 10 groups of vocal print samples, by vocal print sample to the laser pulse punched needed for each hole Number is counted, and removes highest umber of pulse and minimum umber of pulse in counting, takes the laser pulse needed for remaining 8 groups of vocal print samples The mean value n of number.

Step 3: laser boring is carried out to workpiece (4) using the optimization laser boring parameter obtaining in step one, by highly sensitive Degree microphone (5) obtains the audio signal of whole drill process, and these audio signals are transferred to oscillography by data wire (7) Device (6), audio signal, after oscillograph (6) filtering, obtains the vocal print feature of whole laser drilling process, by vocal print sample pair Punch the laser pulse number needed for this hole to carry out counting n1, if ξ is 1*n≤n1≤ξ 2*n, judge the up-to-standard of this hole, and no Then, then judge the off quality of this hole, wherein, ξ 1 and ξ 2 is quality coefficient.

3. in a kind of laser boring according to claim 2 on-line monitoring drilling quality method it is characterised in that: above-mentioned In step 3,0.95 < ξ 1 < 1,1 < ξ 2 < 1.1.