CN103341689B - Restrain the apparatus and method suppressing high power laser light deep penetration welding photo plasma - Google Patents

Abstract

The invention discloses a device for constraining and suppressing photoinduced plasma of high-power laser deep penetration welding, which comprises a cooling copper block, a floating air curtain and a positioning component. The cooling copper block consists of two axisymmetric parts, with an arc-shaped surface facing the weld side, and the cooling copper block is cooled by circulating water; the bottom of the cooling copper block is equipped with a floating air curtain, which evenly ejects a certain flow of inert gas; positioning The component is used to fix the restraint structure on the laser welding working head, and keep the relative position of the restraining structure and the laser welding working head fixed. At the same time, a method for confining and suppressing photoinduced plasma of high-power laser deep penetration welding is disclosed. The device and method of the present invention suppress the three-dimensional expansion of photoinduced plasma during high-power laser welding, reduce the fluctuation amplitude of photoinduced plasma, thereby obtaining a stable welding process and good weld shape, and can be widely used in High power laser deep penetration welding field.

Description

Apparatus and method for confinement and suppression of photoinduced plasma in high-power laser deep penetration welding

technical field

The invention relates to the technical field of laser welding, in particular to a device and method for suppressing photoinduced plasma during laser deep penetration welding.

Background technique

Photoinduced plasma is an important physical phenomenon in the process of high-power laser deep penetration welding. If the plasma is not suppressed or suppressed insufficiently, it will seriously affect the welding process. At present, the control methods of photoinduced plasma are as follows:

1. The auxiliary gas purges the laser incident place through the coaxial or side nozzle. This method has a certain purging effect, but usually helium is used as the auxiliary gas, which is very expensive. In order to improve the purging effect of the auxiliary gas, there are literatures and patents on the design and optimization of the nozzle structure, which has a certain effect on solid-state laser and low-power carbon dioxide laser welding, but the effect is not significant in the process of high-power carbon dioxide laser welding , because as the laser power increases, the amount of metal vapor ejected from the keyhole increases, and the plasma above the keyhole expands rapidly and presents the characteristics of violent fluctuations. Although the specially designed nozzle helps to suppress the plasma, there is a certain distance between the side-blowing gas nozzle and the plasma, and the suppression effect is not substantially enhanced. At present, in the actual high-power laser welding process, the violent expansion of the plasma is generally suppressed by increasing the side-blown gas flow rate, but too high a side-blown gas flow rate will easily cause disturbance of the molten pool, which is not easy to stabilize the keyhole and form the weld seam.

2. Using the electromagnetic characteristics of photoplasma, try to dilute the electron density on the laser incident path by adding an auxiliary electric field or magnetic field, so as to reduce the absorption of incident laser energy by photoplasma. The effect of this method is not very significant, although relevant literature has been involved, but no detailed introduction and in-depth analysis have been carried out.

3. Utilize the device to make the welding area a near-vacuum environment, and the photo-induced plasma diffuses and disappears rapidly in the vacuum environment, but this method is difficult to implement in practical applications, and thus is greatly limited.

It can be seen that there is currently no effective suppression method for the photoinduced plasma in the high-power laser deep penetration welding process, it is difficult to ensure the stability of the welding process, and ultimately it is impossible to obtain uniform and ideal penetration. Therefore, those skilled in the art are committed to providing a device and method for effectively suppressing photoplasma during high-power laser deep penetration welding.

Contents of the invention

In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to provide a device and method for suppressing photoplasma during laser deep penetration welding.

In order to achieve the above purpose, a device for restraining and suppressing photoinduced plasma in high-power laser deep penetration welding is provided, which is characterized in that: it includes a cooling copper block, a floating air curtain and a positioning component; the cooling copper block includes two parts, left and right, respectively along the welding The cooling copper block is placed on both sides of the welding seam in the seam direction, and the cooling copper block is provided with an arc-shaped surface facing the welding seam; the floating air curtain is provided under the cooling copper block; the positioning component is provided above the cooling copper block.

Further, the left and right parts of the cooling copper block are axisymmetric.

Further, the cooling copper block is provided with a cooling water inlet and a water outlet.

Further, there is a gap between adjacent sliders of the floating air curtain.

Further, each of the floating blocks is provided with an independent spring.

Simultaneously, it provides a method for confinement and suppression of high-power laser deep penetration welding photoinduced plasma, which is characterized in that it comprises the following steps:

(a) The left and right parts of the cooling copper block having an arc-shaped surface are placed along the weld seam direction, and the arc-shaped surface faces the weld seam;

(b) The floating air curtain ejects inert gas evenly;

(c) Connect the cooling copper block to the laser welding working head with a positioning component.

Further, the inert gas is argon.

Further, the flow rate of argon is set to 10 L/min.

Further, the distance between the left and right parts of the cooling copper block can be manually adjusted according to the process parameters of laser welding, and kept constant during the welding process.

Compared with the prior art, the device and method of the present invention have the following beneficial effects: Adopting the present invention can suppress the diffusion and expansion of photoinduced plasma in the process of high-power laser welding, effectively restrain the size of photoinduced plasma, and weaken the fluctuation range of plasma , so as to obtain a stable welding process and good weld shape, which can be widely used in the field of high-power laser welding.

The idea, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of the present invention.

Description of drawings

Fig. 1 is a structural diagram of the device of the present invention;

Fig. 2 is a structural diagram of the cooling copper block of the present invention;

Fig. 3 is not adopted the photoplasma intensity figure of this method;

Figure 4 is a graph of the photoplasma intensity using the method.

Detailed ways

Below the embodiment of the present invention is described in detail, present embodiment implements under the premise of technical solution of the present invention, has provided detailed embodiment and specific operation process, but protection scope of the present invention is not limited to following embodiment.

Example

As shown in Figure 1, this embodiment includes: cooling copper block 1, cooling water interface 2, height adjustment rod 3, floating air curtain 4, lateral distance adjustment rod 5, air curtain air pipe interface 6, moving ball 7, casing 8, side Blow pipe 9, spring 10, workpiece 11.

The cooling copper block 1 is divided into axisymmetric left and right parts, which are respectively placed on the left and right sides of the welding seam along the welding seam direction of the workpiece 11. The surfaces of the left and right parts of the cooling copper block 1 facing the welding seam are both arranged in an arc shape. Cooling copper block height 15mm. The front end of the left half of the cooling copper block 1 is connected to the cooling water interface 2, and the rear end is also connected to the cooling water interface. The cooling water flows through the left half of the cooling copper block 1, and the circulation of cooling water is realized through the external cooling water tank. Similar to the left half of the cooling copper block 1, the front and rear ends of the right half of the cooling copper block 1 also have a cooling water interface. The distance between the upper end surfaces of the left and right parts of the cooling copper block 1 is 3mm, and the left and right parts are connected by a transverse distance adjustment rod 5, which can ensure that the distance between the left and right parts of the cooling copper block 1 is maintained during the welding process. Constant, the distance between the left and right parts of the cooling copper block 1 can be adjusted before welding according to the laser welding process parameters.

Eight independent floating blocks are arranged under each part of the left and right parts of the cooling copper block 1, and an independent spring 10 is arranged above each floating block, so that the floating block contacts the surface of the workpiece 11. There is a small gap between two adjacent floating blocks, and the height can be adjusted independently, thereby ensuring that each floating block is attached to the surface of the workpiece 11 . Moving ball 7 is installed on the bottom surface of the floating block. The radius of the moving ball 7 is 1mm, and the height of the protruding floating block is 0.3mm. The moving ball 7 is used to reduce the resistance of the floating block moving on the workpiece 11 surface. There is a vertical bronchus in the middle of each floating block, and each bronchus communicates with the main air pipe above the cooling copper block, and one end of the main air pipe is provided with an air curtain air pipe interface 6 . Each floating block is provided with 3 gas injection ports facing the welding seam, and each gas injection port is equipped with a conical cover, and each conical cover has 6 small holes. Spray evenly. Each small hole on each floating block all ejects gas, constitutes floating air curtain 4.

The restraint structure is mainly composed of a cooling copper block 1 and a floating air curtain 4 . The positioning components include a height adjusting rod 3, a sleeve 8 and a connecting rod. The casing 8 matching the outer diameter of the side blowing air pipe 9 is closely connected with the side blowing air pipe 9 through fastening screws. The height adjustment rod 3 fixes the relative position of the cooling copper block 1 and forms a certain downward force on it. The positioning component is used to fix the restraint structure on the laser welding head, move together with the laser welding head during the welding process, and keep the relative position of the restraint structure and the laser welding head fixed.

This fixing method is suitable for the way that the workpiece remains still during welding and the welding is completed by moving the laser head; for some special occasions where the workpiece moves, other structures should be assisted to realize the movement of the restraint structure during the welding process. The position relative to the laser incident point during the welding process.

The welding process of the workpiece is as follows: the laser is incident perpendicular to the workpiece 11, the moving welding speed of the laser head is set to 1m/min, and the cooling copper block 1 with a circular arc surface confines and cools the photoplasma outside the keyhole The floating air curtain 4 forms a compressed air flow close to the upper surface of the workpiece to avoid the rapid expansion of metal vapor after escaping from the keyhole; by increasing the flow velocity of the air flow in the side blowing pipe 9, the static pressure of the side blowing gas on the workpiece surface is increased to enhance Sweeping and suppressing ability of side-blowing gas to photoplasma. During the welding process, the cooling copper block 1 is provided with circulating cooling water through an external cooling water tank; the side blowing gas is a mixture of helium and argon, and the flow rate is 20L/min; the floating air curtain 4 uses pure argon gas, and the flow rate is 10L/min.

The high-power laser referred to in the present invention refers to a laser with a power greater than 6kW. As the laser power increases, the distance between the left and right parts of the cooling copper block 1 should gradually increase, and the principle of increasing the spacing by 1mm for every 2kW increase can be adopted; as the laser power increases, the height of the cooling copper block 1 can also be increased. However, the influence of this parameter on the suppression effect is not very significant.

In order to effectively suppress the photoinduced plasma in the process of high-power laser deep penetration welding, the present invention provides a method for controlling the photoinduced plasma of laser deep penetration welding by using the confinement method. The method uses a pair of specially designed cooling copper blocks The photoplasma outside the hole is mechanically confined and cooled. The arc shape of the cooling copper block 1 facing the welding seam has a significant restraint effect on the metal vapor and photoplasma ejected from the keyhole, and the horizontal and vertical expansion of the photoplasma is hindered and cooled. In addition, the arc-shaped structure of the cooling copper block 1 not only provides a good compression effect, but also helps to increase the lateral flow velocity of the side-blown gas and increase the static pressure of the side-blown gas on the surface of the workpiece, thereby strengthening the effect of the side-blown gas on the photoinduced Plasma purging and suppression ability, obtain the suppression of photoinduced plasma size and fluctuation amplitude, in order to achieve a stable welding process.

Fig. 3 is a diagram of photoplasma intensity without using this method, and Fig. 4 is a diagram of photoplasma intensity using this method. Comparing Fig. 3 and Fig. 4, it can be seen that after adopting the method, the intensity and fluctuation range of the photoinduced plasma are suppressed, and the present invention has achieved obvious beneficial effects.

The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and changes according to the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection defined by the claims.

Claims (6)

1. restrain and suppress the photic isoionic device of high power laser light deep penetration welding, it is characterized in that: comprise cooling copper billet, float gas curtain and positioning element; Described cooling copper billet comprises two parts in left and right, and be placed on weld seam both sides along bead direction respectively, described cooling copper billet is provided with arcwall face towards weld seam; Be provided with described floating gas curtain below described cooling copper billet, between the adjacent floating motion block of described floating gas curtain, there is gap; Described positioning element is provided with above described cooling copper billet.

2. as claimed in claim 1 restraining suppresses the photic isoionic device of high power laser light deep penetration welding, and two, the left and right part of wherein said cooling copper billet axisymmetricly.

3. as claimed in claim 1 restraining suppresses the photic isoionic device of high power laser light deep penetration welding, and wherein said cooling copper billet is provided with cooling water intake and delivery port.

4. as claimed in claim 1 restraining suppresses the photic isoionic device of high power laser light deep penetration welding, and wherein each described rocker piece is furnished with independently spring.

5. the photic isoionic method of contained suppression high power laser light deep penetration welding using device as claimed in claim 1 to carry out, is characterized in that, comprise the following steps:

A two, left and right part that () has the described cooling copper billet of arcwall face is placed along bead direction, and arcwall face is towards weld seam;

B () described floating gas curtain evenly sprays the argon gas that flow velocity is 10L/min;

C described cooling copper billet is connected on laser welding head with positioning element by ().

6. as claimed in claim 5 restraining suppresses the photic isoionic method of high power laser light deep penetration welding, the spacing of two parts in left and right of wherein said cooling copper billet can carry out manual adjustments according to the technological parameter of laser weld, and keeps constant in welding process.