Method for maintaining uniform light spot on laser cladding processing surface and laser cladding processing head

Abstract

The present invention provides a method for maintaining a uniform light spot on a laser cladding processing surface and a laser cladding processing head, wherein a deviated lens is provided, the deviated lens is a focusing lens, and then a QBH output head is installed on the left side of the deviated lens, and a processing workpiece is on the right side; the QBH output head and the processing workpiece are both located on a straight line where a line segment after the focus on both sides of the deviated lens is connected; wherein the distance L between the QBH output head and the deviated lens is ≤ D / tgθ, and is greater than the distance from the focus of the deviated lens to the deviated lens, wherein D is the lens aperture, and θ is the divergence angle of the QBH output laser. In the present invention, since the light spot on the workpiece surface is still a flat-top light spot, during the cladding process, the powder is heated evenly, the processing defects are small, and only slight polishing is required to meet the processing requirements, thereby improving the processing quality and precision while ensuring the processing efficiency, and greatly reducing the cost of processing consumables.

Description

Technical Field

[0001] The invention relates to the field of laser processing, and in particular to a method for maintaining light spot homogenization on a laser cladding processing surface and a laser cladding processing head. Technical Background

[0002] In the machinery industry, hydraulic shafts often fail due to surface wear after being used for a period of time. Laser cladding is currently one of the most economical and effective repair methods, which can restore the surface to meet the precision requirements of size, wear resistance, hardness, corrosion resistance, etc.

[0003] In the prior art, Figure 1 As shown, the main components of the cladding head include: a QBH output head 1, a collimating lens 2 and a focusing lens 3. The light spot emitted from the QBH is a homogenized light spot (flat-top light spot). If it is placed at the focus of the collimating lens, the light spot will form parallel light after passing through the collimating lens and form an image at a distance. The parallel light is then focused by the focusing lens so that the image of the light spot is formed at the focus of the focusing lens. In order to improve the processing efficiency, the processing workpiece 4 is usually placed at a position deviating from the focus by a certain distance (the focus is between the lens and the workpiece) by adjusting the position of the focusing lens to increase the area of ​​the light spot acting on the workpiece surface. However, after the defocusing process, the output light spot has an unclear image on the workpiece surface, and the image of the light spot no longer has the characteristics of flat-top homogenization. As shown in FIG. Figure 2 The figure shows the exit light spot of the existing cladding head. The focus is the clear imaging point of the optical fiber exit light spot, so its energy curve is a flat-top uniform distribution, such as Figure 3 The same beam configuration is unchanged, but the test spot formed no longer maintains a flat-top curve distribution. This results in uneven heating of the powder during the cladding process, causing the cladding surface to fluctuate, resulting in low cladding accuracy and even cracks.

[0004] In actual processing, if the cladding accuracy is low, the thickness required for grinding is relatively large. For example, if a 0.5mm cladding layer is required, it is often necessary to first spray a cladding layer with a thickness of about 1.2mm, and then grind off 0.7mm of thickness to remove the defective parts, so that the cladding layer after polishing is uniform and defect-free. This process will cause great waste of raw materials and increase processing costs. Summary of the invention

[0005] The purpose of the present invention is to provide an improved method for maintaining a homogenous light spot on a laser cladding processing surface and a laser cladding processing head in view of the deficiencies existing in the above-mentioned background technology.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] A method for maintaining a uniform light spot on a laser cladding processing surface comprises: setting a deviating lens, the deviating lens being a focusing lens, and then installing a QBH output head on the left side of the deviating lens, and a processing workpiece on the right side; the QBH output head and the processing workpiece are both located on a straight line where a line segment after connecting the focal points on both sides of the deviating lens is located; wherein the distance L between the QBH output head and the deviating lens is less than or equal to D / tgθ, and is greater than the distance from the focus of the deviating lens to the deviating lens, wherein D is the clear aperture of the deviating lens (5), and θ is the divergence angle of the QBH output laser; the processing workpiece is located between the point where the laser output by the QBH output head is focused and the deviating lens, so that the light spot of the laser output by the QBH output head falls on the processing workpiece.

[0008] A further improvement is to adjust the size of the light spot falling on the workpiece by adjusting the position of the deviation lens.

[0009] As a further improvement, the deviating lens is a convex lens, or a group of two or more convex lenses fixed together, or a concave reflector equivalent to a convex lens.

[0010] A laser cladding processing head comprises a deviated lens, which is a focusing lens. A QBH output head is installed on the left side of the deviated lens, and the QBH output head is located on a straight line where a line segment after the foci on both sides of the deviated lens are connected is located; wherein a distance L between the QBH output head and the deviated lens is less than or equal to D / tgθ, and is greater than a distance from the focus of the deviated lens to the deviated lens; the deviated lens is connected to a moving mechanism; and the QBH output head is installed on a cladding head body.

[0011] As a further improvement, the moving mechanism includes a translation guide cylinder fixedly connected to the cladding head body, the translation guide cylinder is formed with symmetrically arranged long guide grooves, an inner cylinder is slidably connected inside the translation guide cylinder, and the inner cylinder is connected to a slider passing through the long guide groove; the outer peripheral axis of the translation guide cylinder is connected to a rotating cylinder, and a spiral slideway is formed on the rotating cylinder for the slider to pass through, and the deviated lens is fixed in the inner cylinder.

[0012] As a further improvement, the rotating cylinder is fixedly connected to an outer cylinder, and the outer cylinder covers the rotating cylinder.

[0013] As a further improvement, a water cooling ring pipe is installed on the cladding head body.

[0014] The above solution of the present invention has the following beneficial effects:

[0015] 1. Since the light spot on the workpiece surface is still a flat-top spot, the powder is heated evenly during the cladding process, and the processing defects are small. Only slight polishing or no polishing is required to meet the processing requirements. Therefore, while ensuring the processing efficiency, the processing quality and accuracy are improved, and the cost of processing consumables is greatly reduced.

[0016] 2. The present invention facilitates the adjustment of the size of the light spot according to needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the working principle of the existing cladding head;

[0018] Figure 2 The energy distribution diagram of the light spot output by the existing cladding head at the focal position;

[0019] Figure 3 This is a distribution diagram of the light spot energy after the existing cladding head leaves the focus in actual use;

[0020] Figure 4 It is a working schematic diagram of the cladding head of the present invention;

[0021] Figure 5 It is a structural schematic diagram of the cladding head of the present invention;

[0022] Figure 6 It is a structural schematic diagram of the spiral slide. DETAILED DESCRIPTION

[0023] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Embodiment 1:

[0025] The light spot emitted from the QBH is originally a uniform flat-top energy distribution light spot. Therefore, as long as the light spot can be clearly imaged on the workpiece surface, the uniformity of the light spot can be maintained, while improving the processing efficiency and reducing processing defects, thereby reducing the processing cost. Therefore, the solution of the present invention is as follows. Figure 2 A method for maintaining a homogenous light spot on a laser cladding processing surface is shown, wherein A is the focus of the lens, and QBH is placed at a position B that is a certain distance away from the focus of the lens (the distance between QBH and the lens is greater than the focus). After the light emitted from the light spot at QBH is converged by the lens, it will no longer be parallel light, but will converge at point C. The workpiece is placed between point C and the lens by adjustment. At this time, the light spot formed on the workpiece has a larger diameter on the one hand, which is convenient for cladding processing, and on the other hand, it can still maintain clear imaging of the light spot, that is, the light spot on the workpiece surface can still maintain the homogenization characteristics at this time.

[0026] The distance L between the QBH output head and the lens is less than or equal to D / tgθ, where D is the lens aperture and θ is the divergence angle of the QBH output laser. The number of lenses is greater than or equal to 1.

[0027] Example 2

[0028] On the basis of Example 1, a laser cladding head is designed, including a deviated lens 5, which is a focusing lens. A QBH output head 1 is installed on the left side of the deviated lens 5, and the QBH output head 1 is located on the straight line where the line segment after the focus on both sides of the deviated lens 5 is connected; wherein the distance L1 between the QBH output head 1 and the deviated lens 5 is less than or equal to D / tgθ, and is greater than the distance from the focus of the deviated lens 5 to the deviated lens 5; the deviated lens 5 is connected with a moving mechanism, and the QBH output head 1 is installed on the cladding head body 14. The moving mechanism includes a translation guide cylinder 6 fixedly connected to the cladding head body 14, and a symmetrically arranged long guide groove 7 is formed on the translation guide cylinder 6, and an inner cylinder 8 is slidably connected in the translation guide cylinder 6, and the inner cylinder 8 is connected to a slider 9 passing through the long guide groove 7; the outer peripheral axis of the translation guide cylinder 6 is connected to a rotating cylinder 10, and a spiral slideway 11 for the slider 9 to pass through is formed on the rotating cylinder 10; the deviated lens 5 is fixed in the inner cylinder 8.

[0029] The rotating cylinder 10 is fixedly connected to an outer cylinder 12 , and the outer cylinder 12 covers the rotating cylinder 10 .

[0030] The cladding head body 14 is a hollow cylindrical structure with openings at both ends. The upper and lower ends of the inner cavity of the cladding head body are connected cylindrical cavities and conical cavities respectively. The lower end opening of the cladding head body is smaller than the upper end. The cladding head body is provided with a powder channel 15, a protective gas channel 16 and a water cooling ring pipe 13.

[0031] When in use, the rotating outer cylinder 12 drives the rotating cylinder 10 to rotate, and the spiral slideway 11 thereon drives the slider 9 to move left and right along the long guide groove 7, so as to adjust the position of the deviation from the lens 5.

[0032] The above is 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 principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for maintaining a uniform light spot on a laser cladding surface, characterized in that: The method comprises the following steps: setting a deviating lens (5), wherein the deviating lens (5) is a focusing lens, and then installing a QBH output head (1) on the left side of the deviating lens (5), and a processing workpiece (4) on the right side; the QBH output head (1) and the processing workpiece (4) are both located on a straight line where a line segment after connecting the focal points on both sides of the deviating lens (5) is located; wherein a distance L1 between the QBH output head (1) and the deviating lens (5) is less than or equal to D / tgθ, and is greater than a distance from the focus of the deviating lens (5) to the deviating lens (5), wherein D is the distance between the deviating lens (5) and the processing workpiece (4). ) is a clear aperture, θ is a divergence angle of the laser output by the QBH; the processing workpiece (4) is located between the point where the laser output by the QBH output head (1) is focused and the deviation lens (5), so that the light spot of the laser output by the QBH output head (1) is clearly imaged on the processing workpiece (4); the size of the light spot clearly imaged on the processing workpiece (4) is adjusted by adjusting the position of the deviation lens (5); the deviation lens (5) is a convex lens, or a group of two or more convex lenses fixed together, or a concave reflector equivalent to a convex lens.

2. A laser cladding processing head, characterized in that: The invention comprises the following components: a deviated lens (5), the deviated lens (5) being a focusing lens, a QBH output head (1) being installed on the left side of the deviated lens (5), the QBH output head (1) being located on a straight line where a line segment after the focal points on both sides of the deviated lens (5) are connected is located; wherein a distance L1 between the QBH output head (1) and the deviated lens (5) is less than or equal to D / tgθ, and is greater than a distance from the focal point of the deviated lens (5) to the deviated lens (5); wherein D is a clear aperture of the deviated lens (5), and θ is a divergence angle of the QBH output laser; the deviated lens (5) is connected to a moving mechanism; the QBH output head (1) is installed on a cladding head body (14); the moving mechanism comprises a translation guide fixedly connected to the cladding head body (14); The translation guide cylinder (6) is provided with a symmetrically arranged long guide groove (7); an inner cylinder (8) is slidably connected inside the translation guide cylinder (6); the inner cylinder (8) is connected with a slider (9) passing through the long guide groove (7); a rotating cylinder (10) is connected to the outer circumference of the translation guide cylinder (6); a spiral slideway (11) is formed on the rotating cylinder (10) for the slider (9) to pass through; a deviation lens (5) is fixed in the inner cylinder (8); an outer cylinder (12) is fixedly connected to the rotating cylinder (10), and the outer cylinder (12) covers the rotating cylinder (10); a water-cooling ring pipe (13) is installed on the cladding head body (14); and an annular powder feeding compression channel (15) and a protective gas channel (16) are formed on the cladding head body (14).

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