A machining device and machining method for a guide rod

Abstract

This invention provides a processing apparatus and method for a guide rod, including a laser cladding mechanism for cladding the guide rod and a grinding mechanism for grinding the laser-clad guide rod. The laser cladding mechanism includes a first laser cladding head and a second laser cladding head that move independently. The first laser cladding head first clads a specific length from the middle of the guide rod, and then the second laser cladding head clads in the opposite direction from the starting cladding position of the first laser cladding head. The grinding mechanism includes a digitally displayed tool holder, a drive assembly, and a grinding wheel. The digitally displayed tool holder is supported in the middle of the guide rod. The drive assembly includes a drive rod and several transmission connecting rods. The drive rod drives the transmission connecting rods to rotate, thereby causing the guide rod to rotate, so that the grinding wheel performs cyclic grinding of the laser-clad guide rod in the same direction. This processing apparatus solves the problems of large bending deformation, low processing accuracy, and uneven cladding layer during guide rod cladding.

Description

Technical Field

[0001] This invention relates to the field of guide rod processing, and more specifically, to a guide rod processing apparatus and processing method. Background Technology

[0002] Hydraulic anchor drilling rigs, roadheaders, and other equipment are widely used in tunnel and mine support. The guide rod is a key component that guides and stabilizes the reciprocating directional movement of the hydraulic cylinder during operation. During use, due to the complex environment of deep sea and underground tunnels, and the frequent impacts and eccentric loads, the guide rod is prone to reciprocating wear and corrosion, affecting its normal use. To improve the wear resistance and corrosion resistance of the guide rod, the original process typically involved chrome plating the surface with a thickness of 0.1–0.12 mm. However, the chrome plating layer generally has poor corrosion resistance and a weak physical bond with the base material. Especially under eccentric load conditions, the chrome layer is prone to micro-cracks, leading to plating peeling off over prolonged use.

[0003] In traditional surface treatment processes, laser cladding is a suitable process for improving the wear and corrosion resistance of guide rod surfaces. This process has been widely used in hydraulic support columns, piston rods, jack piston rods, marine engineering cylinder piston rods, and tunnel boring machine cylinder piston rods. The outer diameter of the aforementioned cylinder piston rods is in a similar working environment to the guide rod. The laser cladding process for these cylinder piston rods generally involves: semi-finish turning the outer diameter to the pre-cladding dimensions → laser cladding → grinding the outer diameter to the drawing dimensions... However, when laser cladding is applied to guide rods, the following challenges arise: 1. Guide rods are generally slender rods with a large length-to-diameter ratio, with a rod diameter ≤60mm and a length-to-diameter ratio >25. High straightness requirements are needed during pre-cladding machining, making it difficult to ensure machining accuracy. 2. Uneven temperature distribution during the cladding process of slender guide rods with a large length-to-diameter ratio leads to thermal stress accumulation and deformation over a long period. Axial thermal expansion and bending during the cladding process result in bending deformation of the guide rod, and uneven thickness and poor corrosion resistance of the cladding layer after grinding. 3. High dimensional accuracy is required for slender guide rods with a large length-to-diameter ratio. During grinding, the guide rod is prone to elastic deformation, placing high demands on the grinding machine and grinding fixture. Currently used grinding methods cannot guarantee dimensional accuracy and uniformity of the cladding layer thickness. Summary of the Invention

[0004] To address the problems of large bending deformation, low machining accuracy, and uneven cladding layer during guide rod cladding, the technical solution adopted in this invention is: a guide rod processing device, comprising a laser cladding mechanism for cladding on the guide rod and a grinding mechanism for grinding the laser-clad guide rod.

[0005] The laser cladding mechanism includes a first laser cladding head and a second laser cladding head that move independently. When cladding the rotating guide rod, the first laser cladding head first clads a specific length from the middle of the guide rod, and then the second laser cladding head clads in the opposite direction from the starting cladding position of the first laser cladding head, so as to avoid interference between the two laser cladding heads.

[0006] The grinding mechanism includes a digitally displayed scale tool holder, a drive assembly, and a grinding wheel. The digitally displayed scale tool holder is supported in the middle of the guide rod to counteract the elastic deformation of the guide rod by the grinding wheel and to provide feedback on the grinding status of the guide rod so as to adjust the feed rate of the grinding wheel. The drive assembly includes a drive rod and several transmission connecting rods. The drive rod is used to drive the transmission connecting rods to rotate, thereby driving the guide rod to rotate so that the grinding wheel performs cyclic grinding of the laser-clad guide rod in the same direction.

[0007] Based on the above, one end of the guide rod is provided with several bolt holes for connection with the transmission connecting rod, and the transmission connecting rod is connected to the guide rod by connecting bolts.

[0008] Beneficial effects: By opening bolt holes at one end of the tool holder, the transmission connecting rod can be detachably connected to the tool holder. Furthermore, multiple transmission connecting rods can evenly transmit the rotational driving force to the guide rod, avoiding vibration or deformation of the guide rod during rotary grinding, thereby improving grinding accuracy.

[0009] Based on the above, the laser cladding mechanism and the grinding mechanism each use a separate pair of centers to rotate and clamp the guide rod.

[0010] Beneficial effects: The laser cladding mechanism and the grinding mechanism in this invention are two independent mechanisms. The guide rod needs to be clamped on the laser cladding mechanism for laser cladding first, and then disassembled and clamped on the grinding mechanism for grinding, thereby avoiding interference between the laser cladding head and the grinding wheel.

[0011] Based on the above, the guide rod has a center hole at each end that is used to cooperate with the tip.

[0012] The present invention also provides a method for processing a guide rod using the above-described processing apparatus, comprising the following steps:

[0013] The diameter of the quenched and tempered bar stock is ΦD1+3mm, and the length is 6m to 10m. The continuous quenching and tempering production line is used to complete the quenching and high-temperature tempering of the bar stock. The heat treatment hardness requirement is 240HBW to 280HBW.

[0014] Straightening is performed on the quenched and tempered curved bar stock using a roller straightener;

[0015] The precision stripping process involves turning and grinding the bar stock to the required dimensions using a round steel stripping machine. Straightness 0.05 / 100mm, roundness <0.05mm, resulting in high-precision round steel stripping steel;

[0016] Precision sawing is achieved using a fully automatic high-speed metal circular saw. Metal bar stock, sawn to a length of (L+4) mm, where L is the total length of the finished guide rod and ΦD1 is the diameter of the finished guide rod;

[0017] The flat-end milling machine is used to mill the left and right end faces of the guide rod to the total length L, and center holes are drilled on the left and right end faces of the guide rod respectively.

[0018] Milling and drilling are performed with the outer circle of the guide rod as the reference. Mill and drill the bottom hole and thread of the 3×M12 threaded hole on the right end to ensure that the effective length of the thread is ≥30mm.

[0019] The center holes at both ends of the top guide rod are machined, and the chamfers at both ends are machined.

[0020] The center holes at both ends of the outer circle cladding top are preheated with high-frequency induction heating in the middle part of the guide rod, with a preheating section of not less than 200mm and a preheating temperature of 100℃ to 200℃. Two laser cladding heads are used to clad the guide rod. During cladding, the first laser cladding head first clads a specific length from the middle of the guide rod, and then the second laser cladding head clads from the starting cladding position of the first laser cladding head in the opposite direction to avoid interference between the two laser cladding heads and ensure that the outer circle dimension of the bar after cladding is greater than or equal to Φ(D1+0.6)mm.

[0021] The center holes at both ends of the grinding top guide rod are ground, and a digital display scale tool holder is installed in the middle. The outer diameter of the guide rod is rough ground and fine ground using a grinding mechanism. Roughness Ra0.8;

[0022] The center holes at both ends of the top guide rod are precision machined, and the two ends of the guide rod are chamfered to ensure that the roughness of the chamfers at both ends is Ra1.6;

[0023] Using the outer circle of guide rod ΦD1 as a reference, mill and drill the M24 threaded bottom hole and thread, ensuring that the effective thread length is ≥50mm, and chamfer the hole opening;

[0024] Polish the center hole on the right end of the guide rod and chamfer the left end, then polish the outer circle of the guide rod to the desired depth. Ensure a surface roughness of Ra 0.4.

[0025] This invention has significant substantive features and remarkable progress compared to the prior art. Specifically, the guide rod processing device and processing method provided by this invention have the following advantages:

[0026] 1. High-precision round steel stripping is used to ensure straightness of 0.05 / 100mm before cladding. During the turning and grinding process of this round steel stripping machine, the axial clamping deformation during CNC lathe processing is avoided through the drive mechanism and clamping mechanism, resulting in less processing stress. Furthermore, semi-finish turning is no longer required before cladding, thus improving processing efficiency.

[0027] 2. The dual-head laser cladding equipment performs cladding on the outer circle of the guide rod, improving cladding efficiency by more than 80%. It optimizes the cladding path by adopting a collaborative cladding method from the middle to the left and right ends, reducing bending caused by thermal deformation and ensuring a high yield and uniform thickness of the cladding layer. At the same time, preheating before cladding also reduces thermal stress and deformation.

[0028] 3. The grinding processing device of this invention ensures one-time grinding and avoids grinding the step at the tool connection point by turning around. The digital display scale and tool holder ensure the stability of the grinding process and provide precise feedback to adjust the grinding parameters, ensuring that the tolerance, straightness and roundness of the finished guide rod meet the requirements of the drawing.

[0029] 4. Optimize the processing technology. Before cladding, mill and drill 3×M12 threads on the right end. During grinding, the drive mechanism in the grinding device drives the guide rod to rotate, ensuring that it is ground in one go. After cladding and grinding of the M24 thread on the left end, mill and drill to ensure that the reference is consistent during cladding and grinding. Both are center holes at the left and right ends, ensuring the uniformity of the cladding layer thickness, thereby ensuring the corrosion resistance of the guide rod.

[0030] Therefore, the processing apparatus and processing method for guide rods provided by the present invention can solve the defects of low processing accuracy and uneven cladding layer encountered when using laser cladding to improve the corrosion resistance of guide rods. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a guide rod processing device and a guide rod assembly structure.

[0032] Figure 2 This is a schematic diagram of the finished guide rod dimensions in a processing device and method for providing a guide rod.

[0033] Figure 3 This is a right-side view of the structural diagram of a guide rod finished product in a guide rod processing device and processing method.

[0034] Figure 4 This is a schematic diagram of the left-hand side of a guide rod finished product in a guide rod processing device and processing method.

[0035] Figure 5 This is a schematic diagram of the dimensions and structure of the guide rod before cladding in a processing device and method for providing a guide rod.

[0036] Figure 6This is a schematic diagram of the dimensional structure of the guide rod in the cladding state during the processing of a guide rod, provided by a processing device and processing method.

[0037] Figure 7 This document describes the initial appearance of a guide rod subjected to an acidic salt spray test, obtained through a processing device and method.

[0038] Figure 8 This is a diagram showing the appearance of a guide rod after a 7-day acid salt spray test, produced by a processing device and method for the guide rod.

[0039] Figure 9 This is a diagram showing the appearance of a guide rod after 30 days of acidic salt spray testing, produced by a processing device and method for the guide rod.

[0040] In the figure: 1. Machine tool spindle; 2. Transmission connecting rod; 3. Left center hole; 4. Grinding center; 5. Drive rod; 6. Connecting bolt; 7. Coating layer; 8. Guide rod; 9. Digital display scale tool holder; 10. Right center hole; 11. Second laser cladding head; 12. First laser cladding head; 13. Cladding center. Detailed Implementation

[0041] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0042] Example 1

[0043] This embodiment provides a guide rod processing device, such as... Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, it includes a laser cladding mechanism for cladding on the guide rod 8, and a grinding mechanism for grinding the guide rod after laser cladding.

[0044] The laser cladding mechanism includes a first laser cladding head 12 and a second laser cladding head 11 that move independently. When cladding the rotating guide rod 8, the first laser cladding head 12 first clads 50mm from the middle of the guide rod, and then the second laser cladding head 11 clads from the starting cladding position of the first laser cladding head 12 in the opposite direction to avoid interference between the two laser cladding heads.

[0045] The grinding mechanism includes a digitally displayed graduated tool holder 9, a drive assembly, and a grinding wheel. The digitally displayed graduated tool holder 9 is supported in the middle of the guide rod 8, used to counteract the elastic deformation of the guide rod 8 by the grinding wheel, and to provide feedback on the grinding status of the guide rod 8 so as to adjust the feed rate of the grinding wheel. The drive assembly includes a drive rod 5 and several transmission connecting rods 2. The drive rod 5 is used to drive the transmission connecting rods 2 to rotate, thereby driving the guide rod 8 to rotate, so that the grinding wheel performs cyclic grinding of the laser-clad guide rod 8 in the same direction.

[0046] Specifically, one end of the guide rod 8 has several bolt holes for connection with the transmission connecting rod 2, and the transmission connecting rod 2 is connected to the guide rod 8 by connecting bolts 6. The drive rod 5 is connected to the machine tool spindle 1.

[0047] The laser cladding mechanism and the grinding mechanism each employ a separate pair of centers to rotate and clamp the guide rod. Specifically, these can be referred to as a pair of grinding centers 4 and a pair of cladding centers 13. The guide rod has central holes at both ends that mate with the centers. Specifically, these can be referred to as a left central hole 3 and a right central hole 10.

[0048] This embodiment also provides a method for processing a guide rod, including the following steps:

[0049] The diameter of the quenched and tempered bar stock is ΦD1+3mm, and the length is 6m to 10m. The continuous quenching and tempering production line is used to complete the quenching and high-temperature tempering of the bar stock. The heat treatment hardness requirement is 240HBW to 280HBW.

[0050] Straightening is performed on the quenched and tempered curved bar stock using a roller straightener;

[0051] The precision stripping process involves turning and grinding the bar stock to the required dimensions using a round steel stripping machine. Straightness 0.05 / 100mm, roundness <0.05mm;

[0052] Precision sawing is achieved using a fully automatic high-speed metal circular saw. Metal bar stock, sawn to a length of (L+4) mm, where L is the total length of the finished guide rod and ΦD1 is the diameter of the finished guide rod;

[0053] The flat-end milling machine is used to mill the left and right end faces of the bar stock to a total length L, and B2 center holes are drilled on the left and right end faces of the bar stock, respectively, and are denoted as left center hole 3 and right center hole 10.

[0054] Milling and drilling are performed with the outer diameter of the bar stock as the reference. The right end of the 3×M12 threaded bottom hole and thread are milled and drilled to ensure that the effective length of the thread is ≥30mm.

[0055] The B2 center holes at both ends of the top bar stock are precision machined, and 4×15° chamfers are machined at both ends.

[0056] The center holes at both ends of the outer circle cladding top are preheated with high-frequency induction heating in the middle part of the bar stock, with a preheating section of not less than 200mm and a preheating temperature of 100℃ to 200℃. Two laser cladding heads are used to clad the guide rod. During cladding, one laser cladding head first clads 40mm to 60mm of the guide rod from the middle, and then the other laser cladding head clads in the opposite direction from the starting cladding position of the first laser cladding head to avoid interference between the two laser cladding heads and ensure that the outer circle dimension of the bar stock after cladding is greater than or equal to Φ(D1+0.6)mm.

[0057] The grinding head has B2 center holes at both ends, and a digital display scale and tool holder are installed in the middle. The grinding mechanism is used for rough grinding and fine grinding of the outer diameter of the bar stock. Roughness Ra0.8;

[0058] The center holes at both ends of the top are precision machined, and the two ends are chamfered at 4×15° with a surface roughness of Ra1.6.

[0059] Using the outer circle of ΦD1 as a reference, mill and drill the M24 threaded bottom hole and thread, ensuring that the effective thread length is ≥50mm, and the hole opening is chamfered at 1.5×30°;

[0060] Polish the right end of the B2 center hole and the left end of the 1.5×30° chamfer, and polish the outer circle of the guide rod to the desired depth. Roughness Ra0.4.

[0061] Detection

[0062] The guide rod obtained by this invention was tested, and the test results are shown in Table 1. Figure 7 , Figure 8 and Figure 9 As shown in Table 1, the thickness of the cladding layer at different locations was measured using a high-precision coating thickness gauge. Table 1 shows that the guide rod produced by this invention exhibits a relatively uniform cladding layer.

[0063] Table 1. Measurement of cladding layer thickness uniformity (high-precision coating thickness gauge)

[0064] 0-degree angle 63.4μm 65.1μm 60.1μm 90-degree angle 63.3μm 62.0μm 61.0μm 180-degree angle 63.9μm 64.5μm 63.5μm 270-degree angle 61.8μm 64.3μm 62.0μm

[0065] Meanwhile, according to GB / T / 10125-1997 Artificial Atmosphere Corrosion Test - Salt Spray Test, and according to GB / T 6461-2002 Rating of Samples and Specimens After Corrosion Test of Metals and Other Inorganic Coatings on Metal Substrates, the guide rod prepared by the invention was tested. During the test, distilled water or deionized water was used; the pH value of the solution was adjusted to 3.1-3.3 using 0.5 ml / L glacial acetic acid; the temperature inside the salt spray chamber was 35℃±2℃; and the settling velocity was 1.5 ml / L per 80 cm³. 2The flow rate was 1 mL / h to 2 mL / h. The appearance of the guide rod at the beginning of the experiment, on day 7, and day 30 were as follows: Figure 7 , Figure 8 and Figure 9 As shown.

[0066] According to GB / T / 10125-1997 "Artificial Atmosphere Corrosion Test - Salt Spray Test" standard, the stainless steel powder sample with high-speed laser cladding on the guide rod showed no red rust on the surface after 30 days of acidic salt spray test, meeting the level 10 requirements in GB / T 6461-2002 "Rating of Specimens and Test Pieces with Metallic and Other Inorganic Coatings on Metallic Substrates after Corrosion Test".

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for processing a guide rod, comprising the following steps: tempering: the diameter of the rod is ΦD1+3mm, and the length is 6m to 10m, and the rod is quenched and high-temperature tempered by a continuous tempering production line, and the heat treatment hardness is required to be 240HBW to 280HBW; straightening: the curved rod after tempering is straightened by a roller straightening machine; Precision skiving: turning and grinding the bar to size using a round steel skiving machine 0.05 / 100 mm, roundness < 0.05 mm; Fixed-length sawing: using full-automatic high-speed metal circular sawing machine to accurately saw Metal bar, sawing length (L+4) mm, wherein L is the total length of the finished guide rod, and ΦD1 is the diameter of the finished guide rod; flat end milling: the left end face and the right end face of the guide rod are milled by a flat end milling equipment to the total length L, and a center hole is punched in the left end face and the right end face of the guide rod respectively; milling and drilling: the right end 3×M12 threaded bottom hole and thread are milled and drilled with the outer circle of the guide rod as a reference, and the effective length of the thread is ensured to be greater than or equal to 30mm; finishing turning: the center holes at both ends of the guide rod are turned, and the chamfers at both ends are turned; outer circle cladding: the center holes at both ends of the guide rod are turned, the middle part of the guide rod is preheated by high-frequency induction heating, the preheating section is not less than 200mm, the preheating temperature is 100℃ to 200℃, the guide rod is cladded by two laser cladding heads, when cladding, the first laser cladding head clads a specific length from the middle of the guide rod first, then the second laser cladding head clads from the starting cladding position of the first laser cladding head in the opposite direction, so as to avoid the interference of the two laser cladding heads, and ensure that the outer circle size of the rod after cladding is greater than or equal to Φ(D1+0.6)mm; Grinding: the center hole of both ends of the top guide rod is ground, the digital scale follow-up tool rest is installed in the middle, the outer circle of the guide rod is coarsely ground and finely ground by the grinding mechanism , roughness Ra 0.8; finishing turning: the center holes at both ends of the guide rod are turned, the chamfers at both ends of the guide rod are turned, and the roughness of the chamfers at both ends is ensured to be Ra1.6; milling and drilling: the M24 threaded bottom hole and thread are milled and drilled with the ΦD1 outer circle of the guide rod as a reference, and the effective length of the thread is ensured greater than or equal to 50mm, and the hole chamfer is ensured; Polish: the center hole at the right end of the top guide rod and the chamfer at the left end, polish the outer circle of the guide rod to , ensure roughness Ra0.

4.

2. A method of machining a guide bar according to claim 1, characterized in that: a laser cladding mechanism for cladding on the guide rod, and a grinding mechanism for grinding the guide rod after laser cladding; the grinding mechanism comprises a digital display scale follow-up tool rest, a driving assembly and a grinding wheel, the digital display scale follow-up tool rest is supported at the middle part of the guide rod, and is used for offsetting the elastic deformation of the grinding wheel to the guide rod, and feeding back the grinding condition of the guide rod, so as to adjust the feed amount of the grinding wheel; the driving assembly comprises a driving rod and a plurality of transmission connecting rods; the driving rod is used for rotating the transmission connecting rods by driving, and then driving the guide rod to rotate, so that the grinding wheel circularly and integrally grinds the guide rod after laser cladding in the same direction.

3. A method of machining a guide bar according to claim 2, characterized in that: One end of the guide rod is provided with a plurality of bolt holes connected with the transmission connecting rods, and the transmission connecting rods are connected with the guide rod through connecting bolts.

4. A method of machining a guide bar according to claim 2 or 3, characterized in that: The laser cladding mechanism and the grinding mechanism respectively use a pair of separate centers to rotate and clamp the guide rod.

5. A method of machining a guide bar according to claim 4, characterized in that: The guide rod is provided with a center hole at each end for cooperation with the center.

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