CN113210868A - Laser welding method for manufacturing double-layer rib clamping structure - Google Patents

Abstract

The invention discloses a laser welding method for manufacturing a double-layered rib structure. For the double-layer sandwich structure, the thickness of the pneumatic skin is 1.2mm, the ribs are 1.2mm, and the reinforcing skin is 1.0mm. The front and back protection fixtures are used, and the ribs and the skin are connected by laser welding technology to complete the double-layer sandwich structure. manufacture. The traditional process of riveting the ribs and the skin separately is improved, the riveting process, rivet manufacturing and corresponding assembly fixtures are omitted, the manufacturing process is simplified, the work efficiency is improved, the bonding strength is increased, and the weight of the components is reduced. The invention proposes that the double beam laser welding technology is used to connect the ribs and the aerodynamic skin, which does not produce a penetration effect and ensures a uniform and smooth aerodynamic surface; and the laser back welding technology is used to connect the ribs and the strengthening skin to improve the bonding strength.

Description

Laser welding method for manufacturing double-layer rib clamping structure

Technical Field

The invention relates to the manufacture of a double-layer reinforcement structure in aviation manufacturing, which respectively adopts single-beam back welding and double-beam laser welding technologies to manufacture a wallboard component of an aircraft, in particular to a laser welding method for manufacturing the double-layer reinforcement structure.

Background

In the field of aviation manufacturing, in order to improve the load ratio of an airplane and ensure the uniformity and smoothness of a pneumatic surface, a large number of riveting technologies are used for connecting skins and ribs to form a wallboard assembly of a titanium alloy double-layer ribbed structure. The double-layer ribbed structure consists of a rib (with the thickness of 1.2mm) positioned in the middle and skins at the upper side and the lower side, the skin with strict appearance requirements and capable of ensuring smooth airflow is called a pneumatic skin (with the thickness of 1.2mm), and the skin at the other side for improving the strength and the rigidity of the component is called a reinforced skin (with the thickness of 1.0 mm). In order to ensure the uniform and smooth appearance of the pneumatic skin, a countersunk rivet is used for connecting the rib and the pneumatic skin, the height difference between the rivet head and the skin is ensured to be within +/-0.3 mm, and the generation of turbulence and vortex is avoided. Because of the riveting technique, the ribs must be "I" or "ユ" shaped with upper and lower wings to facilitate placement of the rivet and via locations. With the requirements of high speed, high loads and high weight reduction of the aircraft, the current riveting techniques are exposed to the following disadvantages, which are not suitable for the manufacture of the current aircraft.

1) When the ribs and the pneumatic skin are riveted with low pneumatic surface quality, the height difference occurs between the top handle surface of the rivet and the pneumatic surface of the pneumatic skin, so that the pneumatic surface of the airplane is uneven and unsmooth, and eddy and turbulent flow phenomena occur, thereby affecting the pneumatic performance of high-speed flight;

2) the auxiliary weight is increased to rivet the ribs and the skin, the upper wing and the lower wing of each rib are accessories, the function of flying is not realized, only rivets and through holes are arranged, the structural weight is greatly increased, and the weight reduction of an airplane is not facilitated;

3) the riveting process with a long production period needs working procedures of hole making, centering, nail dropping, positioning, upsetting and the like, the process flow and intermediate links are increased, fasteners such as countersunk rivets, nail pulling and the like need to be additionally manufactured, the production period is very long, and the efficiency is reduced.

In order to improve the pneumatic performance, reduce the weight and shorten the production period, how to improve the manufacturing technology of the double-layer ribbed structure becomes a key problem for manufacturing the aircraft with large load and high navigational speed.

Disclosure of Invention

The present invention aims at providing a laser welding method for manufacturing a double-layer reinforced structure to solve the above technical problems.

In order to achieve the purpose, the invention adopts the following technical scheme: a laser welding method for manufacturing a double-layer ribbed structure, comprising the steps of:

step 1), manufacturing a component;

manufacturing the pneumatic skin and the reinforced skin according to the conventional method, and replacing an I-shaped rib or an ユ -shaped rib with an I-shaped rib;

step 2), double-beam welding;

assembling I-shaped ribs and a pneumatic skin according to the position layout of the ribs on the skin, adopting front and back protection measures, adopting a double-beam laser welding method, welding the ribs and the pneumatic skin together from two sides of the ribs, adjusting welding parameters in the welding process, ensuring the penetration depth of the skin to be between 0.5mm and 0.8mm, and ensuring that the pneumatic surface of the pneumatic skin is free from welding leakage and is uniform and smooth;

step 3), correcting ribs;

correcting the shape of the ribs by adopting an orthopedic method, and ensuring that the ribs are vertical to the surface of the pneumatic skin;

step 4), generating a rib curve equation;

generating a curve equation of each rib by using a laser welding head and a scanning laser beam and using a teaching or programming method, and moving a cursor according to the curve equation under the condition that the defocusing amount is not changed to ensure that the laser cursor moves along the center of the upper edge of the I-shaped rib;

step 5), installing a reinforcing skin;

assembling the reinforcing skin to an early-stage welding part according to the position relation and part of the ribs and the reinforcing skin, and completing positioning;

step 6), laser beam back welding;

according to the thickness (1.0mm) of the reinforced skin, the reference value (+1.0mm) of the height direction of the laser welding head is increased, a rib curve equation is used as track guidance, back welding parameters are called, welding of the ribs and the reinforced skin is completed, and the fusion depth of the ribs is guaranteed to be 1.8 mm-2.5 mm.

Compared with the prior art, the invention has the following advantages: 1) the section shape of the rib is improved, the upper wing and the lower wing of the rib are eliminated, and an I-shaped section is adopted. Because the I-shaped section with the smallest area is adopted, the sectional area of the rib is reduced, the weight of the rib and the structure is further reduced, and the effect of reducing weight is achieved. 2) The rib and the skin are connected by adopting a laser welding technology, so that the working efficiency is improved, and the process links are simplified. 3) The pneumatic skin and the ribs are connected by using a double-beam welding technology, so that the surface quality and smoothness of a pneumatic surface are ensured, and high-speed flight is facilitated.

Drawings

FIG. 1 is a schematic view of a riveted double-layer ribbed structural joint;

FIG. 2 is a schematic view of a riveted double-layer ribbed structure;

FIG. 3 is a schematic manufacturing flow diagram of a riveting flow;

FIG. 4 is a schematic view of a joint for dual beam laser welding;

FIG. 5 is a schematic view of a double-layer rib structure by laser beam back welding;

FIG. 6 laser weld joint schematic

Fig. 7 is a schematic view of a laser welding process.

In the figure: the method comprises the following steps of 1, pneumatic covering, 2, reinforcing covering, 3 ribs, 4 countersunk rivets, 5 nails, 6 back welding laser beam directions, 7 back welding seams, 8 double-beam welding seams, 9 pneumatic surfaces, 10 double-beam laser beams, 11 'I' -shaped ribs, 12 scanning laser beams, 13 welding laser beams and 14 laser welding joints.

Detailed Description

The invention is explained in further detail below with reference to the figures and the specific embodiments.

FIG. 1 is a view showing a form of a joint connected by a riveting method; firstly, holes are formed in the designated positions of the pneumatic skin 1 and the ribs 3, and positioning is carried out; secondly, the pneumatic skin 1 and the ribs 3 are riveted together by using the countersunk rivets 4, so that the pneumatic surface 9 of the pneumatic skin is smooth and flat. Finally, holes are made in the reinforcing skin 2, and the reinforcing skin 2 and the ribs 3 are assembled using draw nails 5. When riveting is used, the ribs must be of "I" or "ユ" cross-section, as shown in FIG. 2 for "ユ" cross-section. Fig. 3 shows a plurality of rib assemblies completed by adopting a riveting method, the weight increasing effect is particularly obvious when the riveting technology is adopted, the manufacturing period is long, the efficiency is low, and the uniformity and the smoothness of a pneumatic surface cannot be ensured.

When the double-layer rib clamping structure is manufactured by using a laser welding method, the I-shaped or ユ -shaped section rib is changed into the I-shaped section rib, so that the effect of reducing weight is achieved. Firstly, installing a pneumatic skin 1 and an I-shaped rib 11, welding the pneumatic skin 1 and the I-shaped rib 11 by using a double-beam laser beam 10, forming a double-beam welding seam 8 as shown in figure 4, selecting reasonable welding parameters, ensuring that the penetration depth of the pneumatic skin is 0.5-0.8 mm, and ensuring that a pneumatic surface 9 is uniform and smooth. The reinforcing skin 2 and the "I" shaped ribs 11 are assembled and welded using a laser beam back welding technique in the back welding laser beam direction 6 to form a back weld 7, as shown in fig. 5. The laser welding parameters are adjusted to ensure that the longitudinal penetration of the I-shaped ribs 11 is 1.8 mm-2.5 mm, as shown in FIG. 6.

The double-layer rib clamping structure manufactured by laser welding saves the working procedures of hole making on the pneumatic skin, the reinforcing skin and the ribs and also saves the manufacturing procedures of riveting and riveting. When the back welding is adopted, the I-shaped ribs 11 are shielded by the reinforcing skin 2 and are invisible, and the welding cannot be directly carried out. In order to ensure that the back welding laser beam can be accurately positioned, the scanning laser beam 12 is used for accurately positioning the shape of the I-shaped rib 11 to form a path equation of the welding laser head 14. After the reinforcing skin 2 is installed, the laser welding head 14 is lifted by 1.0mm, then the walking is carried out according to the path equation, and the welding laser beam is used for welding to complete the assembly manufacturing, as shown in fig. 7.

The invention adopts I-shaped ribs and laser welding technology, and achieves the purposes of reducing weight, improving efficiency, changing air inlet surface and the like. The cross section of the I-shaped or ユ -shaped rib at the early stage is changed into an I-shaped cross section, the appearance structure of the rib is improved, wing plates above and below the rib are eliminated, the weight of the rib is reduced, and the purpose of reducing weight is achieved. The rib and the skin are connected by adopting the method of single-beam back welding and double-beam laser welding to manufacture the double-layer rib clamping structure, so that the rivet manufacturing process and the preparation work in the early riveting stage are saved, the production efficiency is improved, and the generation flow is simplified. The rib and the pneumatic skin are connected by using a double-beam laser welding technology, the weld penetration is 0.5-0.8 mm, the pneumatic skin with the penetration depth of 1.2mm is ensured, the smoothness of a pneumatic surface is ensured, and the phenomena of vortex and turbulence are eliminated.

The foregoing is a preferred embodiment of the present invention, and it will be apparent to those skilled in the art that variations, modifications, substitutions and alterations can be made in the embodiment without departing from the principles and spirit of the invention.

Claims (1)

1. A laser welding method for manufacturing a double-layer reinforced structure is characterized by comprising the following steps:

step 1), manufacturing a component;

manufacturing the pneumatic skin and the reinforced skin according to the conventional method, and replacing an I-shaped rib or an ユ -shaped rib with an I-shaped rib;

step 2), double-beam welding;

assembling I-shaped ribs and a pneumatic skin according to the position layout of the ribs on the skin, adopting front and back protection measures, adopting a double-beam laser welding method, welding the ribs and the pneumatic skin together from two sides of the ribs, adjusting welding parameters in the welding process, ensuring the penetration depth of the skin to be between 0.5mm and 0.8mm, and ensuring that the pneumatic surface of the pneumatic skin is free from welding leakage and is uniform and smooth;

step 3), correcting ribs;

correcting the shape of the ribs by adopting an orthopedic method, and ensuring that the ribs are vertical to the surface of the pneumatic skin;

step 4), generating a rib curve equation;

generating a curve equation of each rib by using a laser welding head and a scanning laser beam and using a teaching or programming method, and moving a cursor according to the curve equation under the condition that the defocusing amount is not changed to ensure that the laser cursor moves along the center of the upper edge of the I-shaped rib;

step 5), installing a reinforcing skin;

assembling the reinforcing skin to an early-stage welding part according to the position relation and part of the ribs and the reinforcing skin, and completing positioning;

step 6), laser beam back welding;

according to the thickness (1.0mm) of the reinforced skin, the reference value (+1.0mm) of the height direction of the laser welding head is increased, a rib curve equation is used as track guidance, back welding parameters are called, welding of the ribs and the reinforced skin is completed, and the fusion depth of the ribs is guaranteed to be 1.8 mm-2.5 mm.

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