CN105648436A - Laser-cladding forming process and laser-cladding forming device for curvature solid piece - Google Patents

Abstract

The invention discloses a laser cladding forming process and device for a curvature solid part, wherein the laser cladding forming process includes the following steps: S1, setting the initial negative defocus of the laser cladding head, controlling the base material to be located in the Initial negative defocus position; S2, control the cone-shaped focused laser beam, the powder feeding beam inside the laser beam and the collimated gas, coaxial exit; S3, control the attitude of the laser cladding head, along the radial direction of the curvature solid part, Each melt channel layer is overlapped and clad layer by layer from the inside to the outside. Each melt channel layer formed by lap cladding forms a layer of cladding layer. During the lap cladding process of a layer of cladding layer, the laser cladding head The negative defocus amount of is gradually reduced as the lap cladding progresses; S4, repeating steps S2 and S3, until the curvature solid part is completely formed. The laser cladding forming process of curvature solid parts of the present invention is based on hollow laser and laser powder feeding technology, and aims at the problem of inconsistency of inner and outer arc lengths during the lapping process of curvature solid parts to perform unequal-height overlapping.

Description

Laser cladding forming process and device for curvature solid parts

technical field

The invention relates to the technical field of laser cladding, in particular to a laser cladding forming process and device for a curvature solid part.

Background technique

Laser cladding 3D forming has broad development prospects, and can quickly form parts with complex structures. At present, relatively mature laser cladding rapid manufacturing processes include: laser selective melting technology (SLM) and laser metal deposition technology (LMD).

However, the above two forming processes overlap and stack along the horizontal normal direction, making it difficult to form complex parts with overhanging structures. Moreover, when the general laser cladding lapping technology is lapped along the formed surface, it cannot overcome the problem of inconsistent arc lengths of the inner and outer layers for the forming of curvature solid parts.

Specifically, as shown in Figure 1, the general laser cladding process is lapped along the surface of the front layer, and the defocus amount remains unchanged during the lapping process, and the increase in the height of each layer is equal to h. In this way, during the stacking and overlapping process of curvature parts, if the increment of each layer is h, the growth of the outer layer will not reach H, which will lead to defects in the forming of the workpiece.

Therefore, in view of the above problems, it is necessary to propose a further solution.

Contents of the invention

In view of this, the present invention provides a laser cladding forming process and device for a curvature solid part to overcome the deficiencies in the prior art.

In order to achieve the above object, the present invention provides a laser cladding forming process for a curvature solid part, which includes the following steps:

S1. Set the initial negative defocus of the laser cladding head to 3-4 mm, the laser cladding head can emit a ring-cone focused laser beam, and the ring-cone focused laser beam has a corresponding initial negative defocus position, controlling the base material to be located at the initial negative defocus position;

S2. The control ring conically focuses the laser beam, the powder feeding beam inside the laser beam, and the collimated gas between the laser beam and the powder feeding beam. During the cladding process, they always exit coaxially with respect to the surface to be clad of the base material ;

S3. Control the attitude of the laser cladding head, along the radial direction of the solid part of curvature, overlap and clad each melt channel layer by layer from the inside to the outside, and form each weld channel layer formed by lap cladding to form a layer of cladding layer, In the lap cladding process of a cladding layer, the negative defocus of the laser cladding head decreases gradually with the lap cladding progress;

S4. Steps S2 and S3 are repeated until the curvature solid part is completely formed.

As an improvement of the laser cladding forming process of the curvature solid part of the present invention, the laser cladding forming process further includes: pre-processing the base material and the powder used in the powder feeding beam before step S1.

As an improvement of the laser cladding forming process for curvature solid parts of the present invention, the pretreatment specifically includes: using sandpaper to polish the surface of the base material, and removing oil stains with alcohol, and then cleaning with acetone; Place in an oven at a high temperature for 2 hours, and dry to remove moisture.

As an improvement of the laser cladding forming process for curvature solid parts of the present invention, the diameter of the powder feeding beam inside the annular conical focused laser beam is 2mm.

As an improvement of the laser cladding forming process of the curvature solid part of the present invention, in the step S3, when the formed layer of cladding layer is the initial cladding layer, the corresponding laser cladding layer of each weld layer of the initial cladding layer The negative defocus amount of the head is the initial negative defocus; when the formed cladding layer is not the initial cladding layer, the negative defocus amount of the laser cladding head corresponding to the innermost melt channel layer of the corresponding cladding layer is the initial negative defocus amount Negative defocus.

As an improvement of the laser cladding forming process of the curvature solid part of the present invention, the step S3 specifically includes:

S31. Establish a spatial coordinate system, and set the coordinate values XP[1]-XP[m] of the innermost melt channel layer in each cladding layer;

S32. When cladding each cladding layer, control the laser cladding head to move to the coordinate value position of XP[n], and scan a single track along the z-axis direction, where 1<n<m;

S33. After scanning, control the laser cladding head to return to the coordinate value position of XP[n], control the attitude of the laser cladding head, and move outward along the radial direction of the solid part to the coordinates corresponding to the next melt channel layer At the value position, scan a single track along the z-axis direction;

S34. Step S33 is repeated until the corresponding cladding layer is completely formed.

As an improvement of the laser cladding forming process of the curvature solid part of the present invention, in the step S33, when controlling the attitude of the laser cladding head, the single rotation angle of the innermost cladding nozzle along the radial direction of the curvature solid part is θ;

Among them, θ=h/r, in the formula, h is the lifting amount of the innermost accumulation, and r is the radius of curvature of the innermost arc.

As an improvement of the laser cladding forming process for curvature solid parts of the present invention, in the step S3, the scanning speed of the conical focused laser beam is 6-8mm/s, and the powder supply rate of the powder feeding beam is 7-9g/min , the pressure of the collimated gas is 0.02MPa.

In order to achieve the above purpose, the present invention also provides a laser cladding forming device for curved solid parts, which includes: a high-power laser system, a robot system, a powder feeder, an internal optical powder feeding cladding head, and a collimated gas delivery system.

Compared with the prior art, the beneficial effect of the present invention is that the laser cladding forming process of the curvature solid parts is based on the hollow laser and the optical internal powder feeding technology, and it is aimed at the inconsistency of the inner and outer arc lengths in the lapping process of the curvature solid parts. Problem performing unequal-height lap joints. Furthermore, in the lap cladding process of unequal heights along the radial direction, the defocus amount gradually decreases as the lap cladding proceeds, which overcomes the problem of inconsistency of inner and outer arc lengths in the process of forming curved solid parts, effectively The quality of the curvature entity is guaranteed.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments described in the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Figure 1 is a schematic diagram of the existing laser cladding process for laser cladding and lapping of curvature solid parts;

Fig. 2 is a graph showing the change curve of the layer height and defocus of the hollow laser cladding head;

Fig. 3 is the schematic diagram of the laser cladding forming process of the curvature solid part of the present invention;

Fig. 4 is a principle diagram of a specific embodiment of the laser cladding forming process of a curvature solid part according to the present invention.

detailed description

In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described The embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

The laser cladding forming process of curvature solid parts of the present invention is based on the principle of self-adaptive overlapping of unequal heights, which can automatically adapt to the required growth height according to the difference in arc length at different curvature radii.

Specifically, the unequal-height overlapping adaptive principle is as follows:

The change curve of the layer height and defocus of the hollow laser cladding head is shown in Figure 2. When the negative defocus is greater than 1.5mm (the negative defocus is the absolute value of the working position), the height of the single layer decreases with the increase of the defocus. While the defocusing amount of the cladding head gradually decreases from the inside to the outside, the growth amount gradually increases. It can be seen from Figure 2 that the self-healing interval of the cladding nozzle in this experiment is -1.5mm to -5.5mm. Due to the need to maintain a certain safety distance between the cladding nozzle and the molten pool, there is no test in the range where the negative defocus is greater than 5.5mm. In order to ensure that the inner and outer arc differences are within the self-adaptive range during the forming process, the formula (1) should be satisfied, namely:

(R-r)θ≤δh...(1);

is the absolute value of the difference between the height of the working point and the maximum height of a single track, where R is the curvature radius of the outermost arc, r is the radius of curvature of the innermost arc, θ is a single rotation angle, and δh is the working defocus amount of the inner and outer arcs The height difference of the corresponding single layer below.

In the actual experiment process, the height of the single layer is the dependent variable, and the defocus amount is the independent variable, so the success of the experiment depends on the change of the defocus amount. Approximately, it is considered that the layer degree is directly proportional to the change of the defocus amount, and the single-channel layer height data with the defocus amount between 1.5m and 5.5mm are used for straight line fitting, and the slope of the line is K. So the formula (1) is modified as:

(R-r)θ≤KΔ...(2);

Among them, Δ is the absolute value (mm) of the working defocus difference between the inner and outer layers of the arc. r and R are the inner and outer radius of the arc respectively (mm), and θ is the single rotation angle (radian).

Therefore, when the value of θ is constant, the maximum wall thickness S of the formable part can be obtained according to the formula (2), namely:

S=R-r≤KΔ/θ...(3).

Among them, r and R are the inner and outer arc radii of the arc (mm), K is the slope of the straight line, Δ is the absolute value of the working defocus difference between the inner and outer layers of the arc (mm), and θ is the single rotation angle (radian).

As shown in FIG. 3 , based on the above-mentioned adaptive principle of unequal-height overlapping, the technical solution of the laser cladding forming process for curvature solid parts of the present invention will be described in detail below.

The laser cladding forming process for curvature solid parts of the present invention includes the following steps S1-S4:

S1. Set the initial negative defocus of the laser cladding head to 3-4 mm, the laser cladding head can emit a ring-cone focused laser beam, and the ring-cone focused laser beam has a corresponding initial negative defocus position, The control matrix material is located at said initial negative defocus position.

Wherein, there is a powder feeding beam inside the annular conical focused laser beam, and there is a collimating gas between the annular conical focused laser beam and the powder feeding beam, and the annular conical focused laser beam, powder feeding beam, and collimating gas Keep the coaxial setting. Preferably, the diameter of the powder feed beam is 2mm.

Further, in the laser cladding forming process, before step S1, it also includes: performing pre-treatment on the base material and the powder used in the powder feeding beam. Specifically, the pre-treatment specifically includes: using sandpaper to polish the surface of the base material, removing oil stains with alcohol, and then cleaning with acetone; placing the used powder in an oven at 200 degrees for 2 hours, and drying to remove moisture.

S2. The control ring conically focuses the laser beam, the powder feeding beam inside the laser beam, and the collimated gas between the laser beam and the powder feeding beam. During the cladding process, they always exit coaxially with respect to the surface to be clad of the base material .

S3. Control the attitude of the laser cladding head, along the radial direction of the solid part of curvature, overlap and clad each melt channel layer by layer from the inside to the outside, and form each weld channel layer formed by lap cladding to form a layer of cladding layer, During the lap cladding process of one cladding layer, the negative defocus of the laser cladding head decreases gradually with the progress of lap cladding.

Specifically, during the unequal-height lap cladding process of the laser cladding head, the negative defocus of the laser cladding head gradually decreases. Wherein, when the formed cladding layer is an initial cladding layer, the negative defocusing amount of the laser cladding head corresponding to each melt channel layer of the initial cladding layer is the initial negative defocusing. When the formed cladding layer is not the initial cladding layer, the negative defocus amount of the laser cladding head corresponding to the innermost melt channel layer of the corresponding cladding layer is the initial negative defocus.

As shown in FIG. 4 , based on the above-mentioned zoom adjustment method, the step S3 specifically includes S31-S34:

S31. Establish a spatial coordinate system, and set the coordinate values XP[1]˜XP[m] of the innermost melt channel layer in each cladding layer.

S32. When cladding each cladding layer, control the laser cladding head to move to the coordinate value position of XP[n], and scan a single track along the z-axis direction, where 1<n<m.

That is, XP[n] is the coordinate value of the innermost melt channel layer in the cladding layer for cladding.

S33. After scanning, control the laser cladding head to return to the coordinate value position of XP[n], control the attitude of the laser cladding head, and move outward along the radial direction of the solid part to the coordinates corresponding to the next melt channel layer At the value position, scan a single track along the z-axis direction.

Wherein, when controlling the attitude of the laser cladding head, the single rotation angle of the innermost cladding nozzle along the radial direction of the curvature solid part is θ. Among them, θ=h/r, in the formula, h is the lifting amount of the innermost accumulation, and r is the radius of curvature of the innermost arc.

S34. Step S33 is repeated until the corresponding cladding layer is completely formed.

In addition, in the step S3, the scanning speed of the conical focused laser beam is 6-8 mm/s, the powder feeding rate of the powder feeding beam is 7-9 g/min, and the pressure of the collimated gas is 0.02 MPa.

S4. Steps S2 and S3 are repeated until the curvature solid part is completely formed.

The present invention also provides a laser cladding forming device for curvature solid parts, which includes: a high-power laser system, a robot system, a powder feeder, an internal optical powder feeding cladding head, and a collimated gas delivery system.

Among them, the high-power laser system is used to provide laser light; the robot system is used to control the movement of the optical powder feeding cladding head; the powder feeder is used for optical powder feeding; the optical powder feeding cladding head It is used to form an annular conical focused laser beam with a powder feeding beam inside; the collimated gas delivery system is used to provide collimated gas between the annular conical focused laser beam and the powder feeding beam.

To sum up, the laser cladding forming process of curvature solid parts of the present invention is based on hollow laser and optical internal powder feeding technology, and aims at the problem of inconsistency of inner and outer arc lengths during the lapping process of curvature solid parts. Furthermore, in the lap cladding process of unequal heights along the radial direction, the defocus amount gradually decreases as the lap cladding proceeds, which overcomes the problem of inconsistency of inner and outer arc lengths in the process of forming curved solid parts, effectively The quality of the curvature entity is guaranteed.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only includes an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (9)

1. a curvature physical member laser cladding forming technique, it is characterised in that, described laser cladding forming technique comprises the steps:

The original negative out of focus of S1, setting laser cladding head is 3-4mm, and described laser melting coating head can launch ring taper laser focusing bundle, and described ring taper laser focusing harness has corresponding original negative out of focus position, and control body material is positioned at described original negative out of focus position;

S2, gate ring taper laser focusing bundle, the powder feeding bundle of laser beam inside and the collimation gas between laser beam and powder feeding bundle, in cladding process, all the time relatively body material treat the coaxial outgoing in cladding surface;

The attitude of S3, control laser melting coating head, along the radius direction of curvature physical member, from-inner-to-outer is by each molten channel layer of layer laser overlapping cladding, the each molten channel layer that laser overlapping cladding is formed forms one layer of cladding layer, in the laser overlapping cladding process of one layer of cladding layer, the negative defocusing amount of laser melting coating head carries out with laser overlapping cladding and reduces gradually;

S4, repeating step S2 and S3, be shaped completely to curvature physical member.

2. curvature physical member laser cladding forming technique according to claim 1, it is characterised in that, in described laser cladding forming technique, also comprised before step S1: the powder that body material and powder feeding bundle use is carried out pre-treatment.

3. curvature physical member laser cladding forming technique according to claim 2, it is characterised in that, described pre-treatment specifically comprises: adopt sand paper to be polished on the surface of body material, and with after alcohol wipe oil, then clean with acetone; The powder used is placed 2h in the baking oven of 200 degree, dries and remove moisture.

4. curvature physical member laser cladding forming technique according to claim 1, it is characterised in that, the diameter of the inner powder feeding bundle of described ring taper laser focusing bundle is 2mm.

5. curvature physical member laser cladding forming technique according to claim 1, it is characterized in that, in described step S3, when the one layer of cladding layer formed is initial cladding layer, the negative defocusing amount of the laser melting coating head that each molten channel layer of initial cladding layer is corresponding is original negative out of focus; When the one layer of cladding layer formed and during non-initial cladding layer, the negative defocusing amount of the laser melting coating head that the molten channel layer in inner side of corresponding cladding layer is corresponding is original negative out of focus.

6. curvature physical member laser cladding forming technique according to claim 1, it is characterised in that, described step S3 specifically comprises:

S31, set up volume coordinate system, coordinate figure XP [the 1]��XP [m] of the molten channel layer in inner side is set in described each cladding layer;

When S32, every layer of cladding layer cladding, control laser melting coating head moves to the coordinate figure position of XP [n], scans single track along the z-axis direction, wherein, and 1 < n < m;

S33, scanned, control laser melting coating head is back to the coordinate figure position of XP [n], and the attitude of control laser melting coating head, and the radius direction along physical member, outwards move to the coordinate figure position that next molten channel layer is corresponding, scan single track along the z-axis direction;

S34, repeating step S33, be shaped completely to corresponding cladding layer.

7. curvature physical member laser cladding forming technique according to claim 6, it is characterised in that, in described step S33, when controlling the attitude of laser melting coating head, innermost layer cladding shower nozzle is �� along single corner of the normal direction in the radius direction of curvature physical member;

Wherein, ��=h/r, in formula, h is that lifting amount is piled up in inner side, and r is most inner arc radius-of-curvature.

8. curvature physical member laser cladding forming technique according to claim 1, it is characterised in that, in described step S3, the sweep velocity of ring taper laser focusing bundle is 6-8mm/s, and the confession powder rate of powder feeding bundle is 7-9g/min, and the air pressure of collimation gas is 0.02MPa.

9. a curvature physical member laser cladding forming device, it is characterised in that, described curvature physical member laser cladding forming device comprises: high powered laser system, robot system, powder feeder, inner-light powder-supplying cladding head, collimation gas delivery system.