Laser marking device and method capable of detecting polyethylene pipeline

Abstract

The invention discloses a detectable polyethylene pipeline laser marking device and method, and relates to the technical field of polyethylene pipeline processing detection. The device comprises a marking table, an arch-shaped frame, transverse and longitudinal limiters, a linkage part, a marker and a distance controller, the transverse and longitudinal limiter comprises a transverse limiting rod and a longitudinal limiting plate, and the linkage component drives the laser head and the longitudinal limiting plate to descend synchronously by utilizing the action of forcing the transverse limiting rod to open when the polyethylene pipeline is pushed in, so that centering and focal length self-adaptive adjustment of the polyethylene pipeline are realized; the marking device utilizes a preheating air curtain to primarily soften the pipe wall, a laser head secondarily melts the pipe wall, then detectable powder is implanted, and a smooth marking belt internally containing metal or magnetic substances is formed on the surface of the polyethylene pipeline. The underground detectability of the polyethylene pipeline is achieved, the functions of profiling marking, product anti-counterfeiting and high-precision positioning are achieved, and the problems that underground detection cannot be achieved and marking quality is unstable in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the technical field of polyethylene pipe processing and inspection, and in particular to a laser marking device and method for detecting polyethylene pipes. Background Technology

[0002] Polyethylene pipes are widely used in urban gas transmission, water supply and drainage, agricultural irrigation and industrial fluid transportation due to their advantages such as corrosion resistance, good flexibility and reliable connection. However, with the continuous expansion of the pipeline network, permanent, clear and traceable identification of the pipelines has become a key link to ensure the safe operation of the pipeline network and realize intelligent management and maintenance.

[0003] Among these, using lasers to make permanent markings on pipe surfaces has become a trend.

[0004] For example, Chinese patent CN204749532U discloses a push-pull type laser marking machine for plastic pipes, which includes a fiber laser, a laser head, an operation touch screen, a bracket, a rotating chuck, casters, a push handle, a control box, a stop block, and a column. The push-pull type laser marking machine for plastic pipes can be operated by hand, can mark plastic pipes of different diameters, can perform online flying laser marking on the plastic pipe production site, and can ensure that the markings on the pipes are perpendicular to or parallel to the axis of the pipes in the plastic pipe storage site.

[0005] However, the laser marking machines used for the aforementioned pipelines still have some shortcomings in actual use: 1. First, polyethylene itself has excellent insulation properties, is non-conductive and non-magnetic, making it difficult to accurately locate buried polyethylene pipelines using traditional detection equipment during subsequent maintenance, repairs, or construction avoidance. Traditional solutions typically involve laying metal tracer wires or warning tapes above the pipeline. However, tracer wires are prone to breakage during backfilling or failure due to corrosion over time, leading to signal interruption. Warning tapes are often buried too shallowly, failing to accurately reflect the pipeline's deeper location, ultimately failing to solve the problem of difficult underground detection.

[0006] 2. Secondly, most existing pipeline laser marking equipment is designed for fixed pipe diameters, resulting in poor versatility. When dealing with polyethylene pipes of different diameters, it is often necessary to manually and cumbersomely adjust the laser focal length and clamping mechanism, and the existing equipment has poor stability in pipe clamping.

[0007] Therefore, based on the above-stated viewpoints, there is still room for improvement in existing laser marking machines for pipelines. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides a laser marking device and method for detecting polyethylene pipes, employing the following technical solution: A laser marking device for detecting polyethylene pipes includes a marking stage and an arched frame at its upper end, with a processing area between the arched frame and the marking stage; within the processing area of ​​the marking stage, there are also: transverse and longitudinal limiters for limiting the polyethylene pipe; and a marking device for laser marking the polyethylene pipe. The transverse and longitudinal limiters include a transverse limit rod for limiting the horizontal direction of the polyethylene pipe and a longitudinal limit plate for limiting the vertical direction of the polyethylene pipe. A linkage component is provided between the transverse limit rod and the longitudinal limit plate, and a preheating air curtain system is also provided on the longitudinal limit plate. The marking device includes a laser head for laser marking the surface of a polyethylene pipe and a powder sprayer distributed circumferentially around the laser head. The laser head is used to melt the pipe surface, and the powder sprayer is used to spray detectable powder into the molten area. When the polyethylene pipe enters the processing area, forcing the lateral limit rod to move outward, the longitudinal limit plate and the marker are driven to move downward synchronously through the linkage component to adapt to different pipe diameters and adjust the focal length.

[0009] Preferably, several limiting posts are slidably installed on the arched frame. One side of the limiting post extends toward the middle of the arched frame and is connected to the transverse limiting rod. A compression spring is sleeved on the limiting post to drive the transverse limiting rod to always converge toward the middle of the processing area.

[0010] Preferably, a linkage component is provided between the transverse limiting rod and the longitudinal limiting plate. The linkage component includes a linkage bar connected to the top of the transverse limiting rod, a linkage gear rotatably located in the middle of the arch frame, and a lifting gear coaxially mounted on the linkage gear. The two sets of opposing linkage bars are engaged with the upper and lower sides of the linkage gear, so that the two linkage bars move horizontally in opposite directions and drive the linkage gear to rotate together. A lifting bar is installed on the side of the laser head near the lifting gear. The lifting bar slides on the side wall of the arched frame via a guide rail. The lifting bar meshes with the lifting gear and is used to convert the rotational motion of the lifting gear into the vertical lifting motion of the laser head and the longitudinal limiting plate.

[0011] Preferably, the marking device also includes a ceramic spacer wheel that contacts the surface of the polyethylene pipe and a guide post for controlling the floating direction of the laser head; The ceramic fixed-distance wheel is hinged to the rotating bracket, which is hinged to the bottom of the longitudinal limiting plate by a torsion spring. The guide posts are distributed in a rectangular shape on the top of the longitudinal limiting plate, and the laser head slides through several guide posts. A traction spring sleeved on the guide posts is provided between the guide posts and the laser head.

[0012] Preferably, the preheating air curtain system includes air holes opened on the longitudinal limiting plate, an air jet pipe inserted into the air hole, and a pump body on the back side of the air jet pipe for delivering hot air to the air hole, thereby driving the air hole to continuously spray hot air curtain.

[0013] Preferably, one side of the longitudinal limiting plate is also provided with a follow-up rolling plate that presses against the wall of the polyethylene pipe, and the follow-up rolling plate is provided with a follow-up spring telescopic rod that slides through the bottom of the longitudinal limiting plate.

[0014] Preferably, the transverse limiting rod is provided with several diagonal rods at equal intervals, which are used to convert the thrust into a lateral force that forces the transverse limiting rod to open outward when the polyethylene pipe is pushed forward.

[0015] Preferably, the powder sprayer includes a powder box mounted on top of the laser head, a powder spraying pipe connected to one side of the powder box, and a powder outlet connected to the powder spraying pipe and spraying powder.

[0016] Preferably, a working port for laser head engraving is opened in the middle of the longitudinal limiting plate.

[0017] Secondly, this application also provides a method for detecting laser marking on polyethylene pipes, as shown below: S1. Product Placement: Push the polyethylene pipe into the processing area. The polyethylene pipe pushes open the horizontal limit bar, and at the same time, the linkage component drives the longitudinal limit plate and the marker to descend, so as to achieve centering and focusing. S2. Surface preheating: After the longitudinal limiting plate comes into contact with the surface of the polyethylene pipe, hot air is sprayed onto the product surface to clean and soften the area to be marked. S3, Melting and Powder Spraying: Start the laser head to scan and melt the preheated area; simultaneously start the powder sprayer to spray powder into the molten area; S4. Rolling and curing: The polyethylene pipe is extracted, and its surface is squeezed to form a smooth, dense, and detectable marking strip. S5. Product Reset: After the polyethylene pipes are removed, they are collected and each component automatically resets under the action of springs, ready for the next processing.

[0018] In summary, this application includes at least one of the following beneficial technical effects: I. The linkage component of this invention ingeniously transforms the horizontal thrust of the polyethylene pipe into the vertical feed motion of the laser head; when the pipe diameter changes, the lateral opening automatically determines the depth of the laser head descent, thus achieving automatic centering of pipes of different diameters and adaptive adjustment of the laser focal length without manual intervention, greatly improving processing efficiency and equipment versatility.

[0019] II. This invention utilizes laser thermal melting and powder spraying technology. At the instant the laser beam softens the pipe wall, metallic or magnetic detection powder is precisely implanted. The powder is then contained within the pipe wall by the cooling and solidification of the substrate. This allows non-metallic polyethylene pipes to be accurately located by metal detectors even after deep underground burial. Furthermore, through a specific powder formulation, the marking layer also possesses anti-counterfeiting identification capabilities.

[0020] Third, the present invention sets up auxiliary processing mechanisms before and after marking: before marking, a preheating air curtain system is used to remove moisture and oil stains from the pipe wall and pre-soften the surface to improve the powder fusion; after marking, a follow-up rolling plate is used to press the semi-molten area in real time, which not only compacts the powder into the inside of the pipe wall, but also smooths the weld beads and burrs, forming a flat and smooth permanent marking band, avoiding stress concentration caused by surface roughness. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a first-view structural diagram of the main body of the invention.

[0023] Figure 2 This is a second-view structural diagram of the main body of the invention.

[0024] Figure 3 This is a first-view structural diagram of the arched frame, the horizontal and vertical limiters, and the marking device of the present invention.

[0025] Figure 4 This is a second-view structural diagram of the arched frame, horizontal and vertical limiters, and marking device of the present invention.

[0026] Figure 5 This is a schematic diagram of the structure between the linkage component, the lateral limiting rod, and the longitudinal limiting plate of the present invention.

[0027] Figure 6 This is a schematic diagram of the structure of the marking device of the present invention.

[0028] Figure 7 This is a schematic diagram of the structure between the marking device and the powder sprayer of the present invention.

[0029] Figure 8 This is a schematic diagram of the preheating air curtain system of the present invention.

[0030] Figure 9 This is a schematic diagram of the distance controller of the present invention.

[0031] Figure 10 This is a flowchart of the laser marking method for detecting polyethylene pipes according to the present invention.

[0032] Explanation of reference numerals in the attached diagram: 1. Marking stage; 2. Arched frame; 3. Horizontal and vertical limiters; 4. Marker; 5. Distance controller; 30. Horizontal limit rod; 31. Vertical limit plate; 40. Laser head; 41. Ceramic spacer wheel; 42. Guide post; 43. Traction spring; 20. Limiting post; 21. Compression spring; 6. Linkage component; 61. Linkage bar; 62. Linkage gear; 63. Lifting gear; 64. Lifting bar; 50. Extension plate; 5 1. Limiting slide; 52. Reference plate; 53. Adjustment knob; 54. Traction rope; 55. Reset spring; 7. Internal engraving device; 70. Telescopic positioning column; 71. Second laser head; 8. Preheating air curtain system; 80. Air hole; 81. Air jet pipe; 82. Pump body; 310. Follow-up rolling plate; 311. Follow-up spring telescopic rod; 45. Powder sprayer; 450. Powder box; 451. Powder spraying pipe; 452. Powder outlet; 300. Inclined rod. Detailed Implementation

[0033] The following combination Figures 1-10 This application will be described in further detail.

[0034] The present invention aims to address the deficiencies in the prior art and provides a detectable polyethylene pipe laser marking device that can automatically adapt to polyethylene pipes 10 of different diameters, achieve high-precision laser marking, and has the function of adding auxiliary detection materials. It can realize automatic centering and adaptive adjustment of polyethylene pipes 10, ensuring marking quality and detection performance.

[0035] Example 1: Reference Figure 1 As shown, a laser marking device for detecting polyethylene pipes includes a marking platform 1 for supporting the polyethylene pipe 10. The marking platform 1 not only supports the heavy polyethylene pipe 10, but also serves as the mounting base for all precision motion mechanisms. An arched frame 2 is installed above the marking platform 1. The arched frame 2 has an inverted U-shaped structure and spans across both sides of the marking platform 1, forming a rectangular processing area together with the surface of the marking platform 1. The processing area is the core area where the polyethylene pipe 10 passes through and is inspected and marked.

[0036] Let's look again. Figure 1 As shown, in order to ensure that the pipeline can maintain a stable state after entering the processing area, three sets of components with different functions are also set in the processing area: the first is the horizontal and vertical limiters 3 responsible for spatial geometric constraints on the pipeline; the second is the marking device 4 that performs the actual marking task; and the third is the distance controller 5 that precisely controls the marking start point and length.

[0037] The three parts work together to automatically transform a polyethylene pipe 10 with bending and ellipticity errors into a workpiece with precise positioning and controllable surface condition, which facilitates subsequent rapid laser marking.

[0038] When a polyethylene pipe 10 is pushed along the marking table 1 to the processing area below the arch frame 2, the horizontal and vertical limiters 3 will first trigger to clamp the polyethylene pipe 10 in multiple directions to ensure the stability of its processing position.

[0039] Reference Figure 2 and Figure 3 As shown, the horizontal and vertical limiters 3 include a horizontal limit rod 30 that limits the polyethylene pipe 10 in the horizontal direction and a vertical limit plate 31 that limits the polyethylene pipe 10 in the vertical direction.

[0040] Several limiting posts 20 are slidably mounted on the arched frame 2. One side of each limiting post 20 extends toward the center of the arched frame 2 and connects to a transverse limiting rod 30. A compression spring 21 is fitted onto each limiting post 20 to keep the transverse limiting rod 30 centered and compressed. The compression spring 21 is always in a pre-compressed state, and the elastic force it generates is transmitted to the transverse limiting rod 30 through the limiting posts 20, forcing the two opposing transverse limiting rods 30 to always converge toward the center line of the processing area.

[0041] Several diagonal braces 300 are provided at equal intervals on the transverse limiting rod 30.

[0042] Specifically, during the pushing process, the polyethylene pipe 10 first contacts the inclined bar 300 on the transverse limiting bar 30, and then applies an external force to the transverse limiting bar 30, forcing the transverse limiting bar 30 to move to both sides until the polyethylene pipe 10 passes through the transverse limiting bar 30. Then, under the elastic force of the compression spring 21, the transverse limiting bar 30 abuts against both sides of the polyethylene pipe 10, providing clamping force to the polyethylene pipe 10 and achieving horizontal transverse limiting of the polyethylene pipe 10.

[0043] When the polyethylene pipe 10 is inserted between the two transverse limiting rods 30, the outer wall of the polyethylene pipe 10 will squeeze the transverse limiting rods 30, forcing them to overcome the resistance of the compression spring 21 and move outward. Since the compression springs 21 on the left and right sides are the same and the mechanical structure is symmetrical, it is ensured that the left and right clamping forces on the polyethylene pipe 10 are balanced regardless of the diameter of the polyethylene pipe 10.

[0044] After the polyethylene pipe 10 achieves horizontal lateral limitation during the pushing process, it can also achieve vertical limitation.

[0045] Reference Figure 4 and Figure 5 As shown, a linkage component 6 is provided between the transverse limiting rod 30 and the longitudinal limiting plate 31. The linkage component 6 includes an arched frame 2 installed on the marking table 1, a linkage bar 61 connected to the top of the transverse limiting rod 30, and a linkage gear 62 rotatably connected to the middle of the arched frame 2.

[0046] The linkage bars 61 on the two sets of transverse limiting rods 30 are both engaged with the linkage gear 62, and the two linkage bars 61 are located on the upper and lower sides of the linkage gear 62. The linkage gear 62 is also coaxially mounted with a lifting gear 63 rotatably mounted on the arch frame 2. A lifting bar 64 is installed on the side of the laser head 40 near the lifting gear 63. The lifting bar 64 is slidably mounted on the side wall of the arch frame 2 through the guide rail, and the lifting bar 64 is engaged with the lifting gear 63.

[0047] The working process is as follows: When the polyethylene pipe 10 is pushed, it forces the lateral limiting rods 30 on both sides to open outward, and at the same time drives the horizontal linkage bar 61 to move outward. Since the two linkage bars 61 are respectively engaged at the upper and lower ends of the linkage gear 62, their horizontal opposite movements will jointly drive the middle linkage gear 62 to generate rotational motion.

[0048] While the linkage gear 62 rotates, it controls the coaxial lifting gear 63 to move synchronously. The lifting gear 63 meshes with the lifting bar 64. Therefore, when the lifting gear 63 rotates, it controls the lifting bar 64 and the laser head 40 to move downwards towards the polyethylene pipe 10 synchronously. While the laser head 40 moves downwards, it controls the longitudinal limiting plate 31 to move downwards synchronously through the guide column 42.

[0049] At this time, the ceramic spacer wheel 41 at the bottom of the longitudinal limiting plate 31 first contacts the surface of the polyethylene pipe 10. After the ceramic spacer wheel 41 at the bottom of the longitudinal limiting plate 31 contacts the surface of the polyethylene pipe 10, as the laser head 40 continues to move downward, the traction spring 43 will be squeezed. At this time, the greater the force of the ceramic spacer wheel 41 and the longitudinal limiting plate 31 against the surface of the polyethylene pipe 10, the more the polyethylene pipe 10 will be longitudinally limited.

[0050] Once the polyethylene pipe 10 is restricted in both the horizontal and vertical directions, the marking device 4 can begin to work.

[0051] Reference Figure 6 and Figure 7 As shown, the marking device 4 includes a laser head 40 for laser marking the surface of the polyethylene pipe 10, a ceramic spacer wheel 41 that contacts the surface of the polyethylene pipe 10, and a guide post 42 for controlling the floating direction of the laser head 40.

[0052] The ceramic spacer wheel 41 is hinged to the rotating bracket, which is hinged to the bottom of the longitudinal limiting plate 31 by a torsion spring. The guide posts 42 are rectangularly distributed on the top of the longitudinal limiting plate 31, and the laser head 40 slides through several guide posts 42. A traction spring 43 is provided between the guide posts 42 and the laser head 40 and is sleeved on the guide posts 42.

[0053] The laser head 40 is also equipped with a powder sprayer 45 in the circumferential direction.

[0054] The longitudinal limiting plate 31 rests against the surface of the polyethylene pipe 10 mainly by the ceramic spacer wheel 41, which can float and buffer through the rotating bracket.

[0055] During operation, due to the pressure of the traction spring 43, the ceramic spacer wheel 41 always rolls in close contact with the surface of the polyethylene pipe 10; if the wall of the polyethylene pipe 10 bulges locally, the ceramic spacer wheel 41 is lifted up, causing the entire laser head 40 to float upward along the guide post 42; if the wall of the polyethylene pipe 10 is concave, the traction spring 43 will press the laser head 40 to sink accordingly.

[0056] The ceramic material ensures that even in the high heat radiation area of ​​the laser, the ceramic spacer wheel 41 will not undergo thermal deformation or stick to the molten plastic, ensuring that the laser focus always falls precisely on the surface of the polyethylene pipe 10, thus guaranteeing that the thickness and depth of the engraved lines are uniform.

[0057] Reference Figure 8 As shown, another major highlight of this application is the realization of the detection function. A preheating air curtain system 8 is integrated on the longitudinal limiting plate 31. The system includes air holes 80 opened on the plate, an inserted jet pipe 81, and a pump body 82 at the rear end (existing known equipment); the pump body 82 is a constant temperature hot air generator, and the hot air curtain continuously sprays for 0.5-2 seconds, raising the surface temperature of the polyethylene pipe wall to 105-120 degrees, reaching a thermoplastic softening state but not melting.

[0058] Before or during marking, the pump 82 is activated, and heated air is delivered to the air hole 80 through the jet pipe 81 to form a continuously jetting hot air curtain. This hot air acts directly on the surface of the pipe that will be laser-marked. The preheating has two functions: first, to remove moisture and oil from the surface of the pipe to prevent the laser energy from being absorbed or scattered; second, to soften the skin of the polyethylene pipe 10 in advance so that it enters a thermoplastic state.

[0059] Immediately afterwards, the powder sprayer 45 arranged around the laser head 40 begins to work. The powder sprayer 45 is loaded with special metal powder or magnetic powder (detectable material). When the laser beam irradiates the softened polyethylene pipe wall 10 and instantly generates a high-temperature molten pool, the powder sprayer 45 accurately sprays a small amount of detection powder into the molten pool.

[0060] Since the surface of the polyethylene pipe 10 has been preheated and is in a molten state, the powder can easily fuse with the polyethylene matrix. Once the molten polyethylene matrix solidifies, it can contain the sprayed powder and make it integrate with the polyethylene pipe 10. In this way, no matter how deep the pipe is buried, the location of the polyethylene pipe 10 and its underground depth can be determined by detecting the powder through a detector.

[0061] Furthermore, it can also prevent counterfeiting because the powder sprayed is a specific powder. Therefore, by directly testing the powder, the authenticity of the polyethylene pipe 10 can be determined based on the powder composition ratio and the amount of powder, which effectively improves the anti-counterfeiting measures.

[0062] Reference Figure 7 and Figure 8 As shown, the powder sprayer 45 includes a powder box 450 mounted on the top of the laser head 40, a powder spraying pipe 451 connected to one side of the powder box 450, and a powder outlet 452 connected to the powder spraying pipe and spraying powder.

[0063] The powder box 450 stores powder and can deliver the powder through the powder spraying pipe 451 to the powder outlet 452, so that it can be sprayed onto the surface of the molten polyethylene pipe 10 at a constant density.

[0064] The detectable powder is a mixture of carbonyl iron powder with an average particle size of 1-10 micrometers and nano-sized silica, wherein the carbonyl iron powder accounts for 85%-95% and the silica as a dispersant accounts for 5%-15%; the powder with this ratio can be uniformly dispersed and coated in the molten state of polyethylene matrix, and after cooling, it forms a marking band with strong magnetic responsiveness.

[0065] Looking back Figure 7 As shown, in order to prevent uneven weld beads or burrs from appearing on the surface of the molten polyethylene pipe 10, a follower rolling plate 310 that can move up and down is specially installed on one side of the longitudinal limiting plate 31; the follower rolling plate 310 is provided with a follower spring telescopic rod 311 that slides through the bottom of the longitudinal limiting plate 31; the compression and extension of the spring telescopic rod 311 can control the follower rolling plate 310 to fit against the surface of the polyethylene pipe 10.

[0066] The follow-up compaction plate 310 can extrude the semi-molten area where the marking and powder have been implanted. After the polyethylene pipe 10 is laser-marked, it is removed. During this process, the follow-up compaction plate 310 compacts the powder into the interior of the polyethylene pipe 10 wall. After cooling, a smooth, flat, permanent marking strip containing metallic magnetic material is formed on the surface of the polyethylene pipe 10. This marking strip is not only visible but also easily detected by ground metal detectors, thus achieving the purpose of detection.

[0067] Example 2: Based on Example 1, in order to accurately control the position of the marking, this application also proposes a distance controller 5.

[0068] Reference Figure 9As shown, the distance controller 5 includes an extension plate 50 that is slidably mounted on the marking stage 1. The marking stage 1 also has a limiting groove 51 for the extension plate 50 to slide. A reference plate 52 is integrally mounted on one side of the extension plate 50 for the polyethylene pipe 10 to abut against for reference adjustment.

[0069] The marking stage 1 is also equipped with a rotatable adjustment knob 53, and a traction rope 54 is installed on the reference plate 52. The traction rope 54 slides through the marking stage 1 from the reference plate 52 and extends in the direction of the adjustment knob 53. The traction rope 54 is wound around the adjustment knob 53. A reset spring 55 is also provided between the extension plate 50 and the marking stage 1.

[0070] On the surface of the marking stage 1, a parallel limiting groove 51 is provided, in which an extension plate 50 is slidably installed. A reference plate 52 is integrally cast on one side of the extension plate 50. This reference plate 52 acts as a physical stop on the end face of the polyethylene pipe 10. When the operator places the pipe, he presses one end of the pipe against the reference plate 52, which determines the zero point of machining.

[0071] To adjust the position of this zero point relative to the laser head 40, a distance adjustment knob 53 is provided on the marking stage 1 and is connected to the reference plate 52 via a high-strength traction rope 54.

[0072] Rotating the adjustment knob 53 will release the traction rope 54 to a specified length. When the polyethylene pipe 10 is pushed into the processing area, it will squeeze and push the reference plate 52 to move within the limiting groove 51. After the reference plate 52 has moved a specified distance, the traction rope 54 will be tightened and cannot move. At this time, the pushing action of the polyethylene pipe 10 is completed. The position of the polyethylene pipe 10 directly below the laser head 40 is the area that needs to be marked.

[0073] To facilitate resetting, a reset spring 55 is connected between the extension plate 50 and the marking stage 1. When the polyethylene pipe 10 is removed, the tension of the reset spring 55 will automatically pull the extension plate 50 back to its initial position.

[0074] Example 3: In addition to marking the outer wall, the marking requirements for the inner wall of the pipe were also taken into account. A telescopic positioning post 70 was snapped into the middle of the reference plate 52, and a small second laser head 71 was installed at the end of the telescopic positioning post 70.

[0075] When the polyethylene pipe 10 rests on the reference plate 52, the telescopic positioning post 70 extends into the polyethylene pipe 10. According to the set program, the second laser head 71 can engrave the factory number, batch number, or anti-counterfeiting code on the inner wall of the polyethylene pipe 10. This provides double insurance for the full life cycle traceability of the polyethylene pipe 10. Even if the outer wall is severely worn, the markings on the inner wall remain intact.

[0076] In addition, refer to Figure 10 As shown, this application also provides a method for detecting laser marking on polyethylene pipes, as follows: During operation: Step 1: First, according to the specifications and marking position requirements of the polyethylene pipe 10 to be processed, the staff uses the distance controller 5 to adjust the zero point, and by rotating the distance adjustment knob 53 to wind the traction rope 54, the extension plate 50 and the reference plate 52 are moved in the limiting slide groove 51 of the marking table 1 to set the relative distance between the end face of the polyethylene pipe 10 and the laser head 40.

[0077] Step Two: Subsequently, the polyethylene pipe 10 is pushed into the marking platform 1 until the end of the polyethylene pipe 10 rests against the reference plate 52, completing the physical positioning for mechanical processing. At this point, if there is a need for internal wall marking, the internal engraver 7 located in the middle of the reference plate 52 extends into the polyethylene pipe 10 through the telescopic positioning post 70, and uses the second laser head 71 to simultaneously engrave the factory number or anti-counterfeiting code on the inner wall of the pipe. If not, the second laser head 71 is disassembled.

[0078] Step 3: When the polyethylene pipe 10 is pushed into the processing area below the arched frame 2, the outer wall of the polyethylene pipe 10 first contacts and squeezes the inclined bar 300 on the transverse limiting rod 30, forcing the two transverse limiting rods 30 to overcome the resistance of the compression spring 21 and open outward. The horizontal automatic centering of the polyethylene pipe 10 is achieved by using the restoring force of the compression spring 21.

[0079] Step 4: At the same time, the outward movement of the lateral limiting rod 30 drives the linkage gear 62 to rotate through the linkage bar 61, which in turn drives the coaxial lifting gear 63 to rotate synchronously. The lifting gear 63 meshes with the lifting bar 64 on the side of the laser head 40, driving the laser head 40 and the longitudinal limiting plate 31 to automatically descend. When the ceramic spacer wheel 41 at the bottom of the longitudinal limiting plate 31 contacts the surface of the polyethylene pipe 10, the laser head 40 completes the adaptive adjustment of the focal length for different pipe diameters and longitudinal limiting.

[0080] Step 5: The preheating air curtain system 8 integrated on the longitudinal limiting plate 31 is started. The pump body 82 sprays heated air out of the air hole 80 through the jet pipe 81 to form a hot air curtain. This air curtain acts directly on the area to be marked, removing moisture and oil from the surface of the pipe on the one hand, and softening the polyethylene skin in advance to make it enter the thermoplastic state, preparing it for powder implantation.

[0081] Step Six: The ceramic spacer wheel 41 rolls in close contact with the surface of the polyethylene pipe 10. Relying on the tension of the traction spring 43 and the hinge structure of the rotating bracket, the laser head 40 can float up and down with the unevenness of the surface of the polyethylene pipe 10 to achieve contour-following motion and ensure that the laser focus always falls accurately on the surface of the pipe wall.

[0082] Step 7: Subsequently, the laser head 40 begins to operate for laser marking. During the marking process, the laser head 40 irradiates the softened polyethylene pipe wall 10, instantly generating a high-temperature molten pool. Immediately afterwards, the powder sprayer 45 arranged around the laser head 40 precisely sprays metal powder or magnetic powder (detectable material) and melts it into the molten pool, using the molten matrix to encapsulate the powder.

[0083] Step 8: As the polyethylene pipe 10 moves, the follow-up rolling plate 310 located on one side of the longitudinal limiting plate 31 rolls the area that has just been marked and is in a semi-molten state, compacting the detection powder into the inside of the pipe wall and smoothing out any weld beads or burrs that may be generated; after cooling, a smooth and flat permanent marking band is formed on the surface of the polyethylene pipe 10, containing a permanent marking band that can be detected by the detector, thus completing the marking and detection function implantation.

[0084] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A laser marking device for detectable polyethylene pipe, characterized by: The arch-shaped frame (2) and the marking table (1) are provided with a processing area between them; The marking table (1) is further provided with: A horizontal and vertical positioner (3) for limiting the polyethylene pipeline; A marker (4) for laser marking the polyethylene pipeline; The horizontal and vertical positioner (3) comprises a horizontal limiting rod (30) for limiting the polyethylene pipeline horizontally and a vertical limiting plate (31) for limiting the polyethylene pipeline vertically, and a linkage component (6) is arranged between the horizontal limiting rod (30) and the vertical limiting plate (31); The vertical limiting plate (31) is further provided with a preheating air curtain system (8); The marker (4) comprises a laser head (40) and a powder sprayer (45) mounted on the laser head (40), the laser head (40) is used for melting the surface of the pipeline, and the powder sprayer (45) is used for spraying detectable powder to the melting area; When the polyethylene pipeline enters the processing area and forces the horizontal limiting rod (30) to move outward, the linkage component (6) drives the vertical limiting plate (31) and the marker (4) to move downward synchronously to adapt to different pipe diameters and adjust the focal length.

2. The detectable polyethylene pipe laser marking device of claim 1, wherein: A plurality of limiting columns (20) are slidably arranged on the arch-shaped frame (2), one side of the limiting column (20) extends to the middle of the arch-shaped frame (2) and is connected with the horizontal limiting rod (30), and an extrusion spring (21) is sleeved on the limiting column (20) to always gather the horizontal limiting rod (30) to the middle of the processing area.

3. The detectable polyethylene pipe laser marking device of claim 1, wherein: A linkage component (6) is arranged between the horizontal limiting rod (30) and the vertical limiting plate (31), the linkage component (6) comprises a linkage strip (61) connected with the top of the horizontal limiting rod (30), a linkage gear (62) rotatably arranged in the middle of the arch-shaped frame (2), and a lifting gear (63) coaxially arranged on the linkage gear (62); The two groups of oppositely arranged linkage strips (61) are engaged on the upper and lower sides of the linkage gear (62), so that the two linkage strips (61) move horizontally and reversely to jointly drive the linkage gear (62) to rotate; The laser head (40) is installed with a lifting strip (64) on the side close to the lifting gear (63), the lifting strip (64) slides on the side wall of the arch-shaped frame (2) through a guide rail, the lifting strip (64) is engaged with the lifting gear (63), and is used for converting the rotating movement of the lifting gear (63) into the vertical lifting movement of the laser head (40) and the vertical limiting plate (31).

4. The detectable polyethylene pipe laser marking device of claim 1, wherein: The marker (4) further comprises a ceramic fixed-distance wheel (41) in contact with the surface of the polyethylene pipeline and a guide column (42) for controlling the floating direction of the laser head (40); The ceramic fixed-distance wheel (41) is hinged to a rotating support, the rotating support is hinged to the bottom of the vertical limiting plate (31) through a torsional spring, the guide column (42) is distributed in a rectangular shape on the top of the vertical limiting plate (31), the laser head (40) slides through the guide column (42), and a traction spring (43) is sleeved on the guide column (42) between the laser head (40) and the guide column (42).

5. The detectable polyethylene pipe laser marking device of claim 1, wherein: The preheating air curtain system (8) comprises air holes (80) formed on a longitudinal limiting plate (31), and a jet pipe (81) is inserted into the air holes (80), and a pump body (82) for delivering hot air to the air holes (80) is arranged on the back side of the jet pipe (81), so that the air holes (80) continuously spray hot air curtain.

6. The detectable polyethylene pipe laser marking device of claim 1, wherein: The longitudinal limiting plate (31) is further provided with a follow-up rolling plate (310) for pressing the pipe wall of the polyethylene pipe, and the follow-up rolling plate (310) is provided with a follow-up spring telescopic rod (311) slidingly arranged at the bottom of the longitudinal limiting plate (31).

7. The detectable polyethylene pipe laser marking device of claim 1, wherein: The transverse limiting rod (30) is provided with a plurality of inclined rods (300) at equal intervals, which are used to convert the pushing force into lateral force for forcing the transverse limiting rod (30) to open outward when the polyethylene pipe is pushed.

8. The detectable polyethylene pipe laser marking device of claim 1, wherein: The powder sprayer (45) comprises a powder box (400) mounted on the top of the laser head (40), a powder spraying pipe (401) connected with one side of the powder box (400), and a powder outlet (402) connected with the powder spraying pipe and used for spraying powder.

9. The detectable polyethylene pipe laser marking device of claim 1, wherein: A working port is formed in the middle of the longitudinal limiting plate (31) for laser head (40) marking.

10. A method for laser marking a detectable polyethylene pipe using the laser marking device for a detectable polyethylene pipe according to any one of claims 1 to 9, characterized in that: The method is as follows: S1, product placement: the polyethylene pipe is pushed into the processing area, the polyethylene pipe pushes away the transverse limiting rod (30), and the linkage component (6) drives the longitudinal limiting plate (31) and the marker (4) to descend, realizing centering and focusing; S2, surface preheating: after the longitudinal limiting plate (31) contacts the surface of the polyethylene pipe, hot air is sprayed to the surface of the product to clean and soften the area to be marked; S3, melt powder spraying: start the laser head (40) to scan and melt the preheated area; simultaneously start the powder sprayer (45) to spray powder into the melted area; S4, rolling and solidification: after the polyethylene pipe is pulled out, the surface of the pipe is extruded to form a smooth and dense detectable marking belt; S5, product reset: after the polyethylene pipe is moved out, it is uniformly collected, and each component is automatically reset under the action of the spring, ready for the next processing.

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