A guide forming process

Abstract

This invention discloses a guide forming process, the key technical points of which include the following steps: S1, component prefabrication; S2, forming-sintering-shaping process; S3, guide body precision machining; S4, bushing press-fit pretreatment; S5, press-fit and interference dynamic judgment: the pretreated bushing is transported to the press-fit station, and the target interference is set as α0; the servo press is started, and a displacement-pressure dual feedback sensor is integrated at the lower end of the press head; S51, initial press-fit judgment: the press head contacts the upper surface of the bushing and applies a preload Fp. If the actual displacement L1 fed back by the displacement sensor is less than the preset idle stroke L0, it is judged that the workpiece is not placed correctly, and the system alarms immediately; otherwise, the formal press-fit begins; S52, press-fit process monitoring; S53, pressure holding and springback judgment; S6, overall aging vibration; S7, machining grooves; S8, polishing treatment; S9, cleaning and drying; S10, final inspection and packaging; this invention is applicable to the field of guide processing technology.

Description

Technical Field

[0001] This invention relates to a guide processing technology, and more specifically, to a guide processing and forming process. Background Technology

[0002] The guide of an automotive shock absorber is a key component ensuring the stability of piston rod movement, and its performance directly affects the ride comfort and safety of the entire vehicle. In traditional guide manufacturing processes, each component is machined independently and then conventionally press-fitted, lacking full-process precision and stress control. Insufficient machining precision of the guide body and bushings can easily lead to uneven fit clearances after assembly. The press-fitting process lacks dynamic monitoring, often resulting in quality defects due to workpiece misalignment, foreign objects on mating surfaces, or out-of-tolerance dimensional and positional issues. Furthermore, residual stress from press-fitting is difficult to effectively eliminate, affecting the product's service life. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a guide forming process that integrates precision machining, dynamic monitoring, and intelligent control.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a guide forming process, comprising the following steps: S1. Prefabrication of accessories: The guide body and bushing are prepared separately; the guide body blank is prepared by powder metallurgy process: metal powder and binder are mixed according to the preset ratio, cold-pressed into green blank, and the green blank is degreased to obtain a prefabricated body suitable for subsequent sintering; the bushing blank is made of high lead-tin aluminum alloy or copper alloy tubing and rough-machined inside and outside. S2. Forming-Sintering-Shaping Process: The preform to be sintered is sent into the sintering furnace for high-temperature sintering, so that the metal powder is metallurgically bonded to form a dense guide body; then the sintered guide body is shaped and sized, and its external dimensions and form and position tolerances are corrected by mold, and internal stress is initially eliminated. S3. Precision machining of the guide body: The guide body is precision machined according to the design requirements. When the end face of the mounting hole is precision ground, the flatness error of the end face is ensured to be ≤0.01mm. Then the mounting hole is bored, and the hole diameter tolerance is controlled within the range of H7 grade, and the surface roughness Ra≤1.6μm. S4. Bushing press-fit pretreatment: Laser microtexturing is performed on the outer cylindrical surface of the bushing blank to form an array of micro-dimples, thereby increasing the contact surface area and oil storage capacity of the subsequent interference fit; at the same time, the inner hole of the bushing is honed to form a uniform cross-texture on its surface, with the cross-texture angle being 60°±5°. S5. Pressing and Dynamic Interference Determination: The pre-treated bushing is transported to the pressing station, and the target interference is set to α0; the servo press is started, and a displacement-pressure dual feedback sensor is integrated at the lower end of the press head. S51. Initial pressing judgment: When the pressing head contacts the upper surface of the bushing and applies a preload force Fp, if the actual displacement L1 fed back by the displacement sensor is less than the preset empty stroke L0, it is judged that the workpiece is not placed correctly and the system will stop and alarm; otherwise, it will enter the formal pressing process. S52. Pressing process monitoring: The press head presses downwards at a constant speed V, and the data of pressing force F and pressing depth L are collected in real time; a pressing force-displacement curve F(L) is constructed, and the slope of the curve K=dF / dL is calculated; if the fluctuation of the slope K in the pressing depth L∈[2mm,10mm] range exceeds ±15% of the initial slope K0, it is judged that there are foreign objects or the form and position tolerances are out of tolerance on the mating surface, the servo motor reverses and exits the bushing, and jumps to S4 to re-perform surface treatment; S53. Pressure Holding and Springback Judgment: When the pressing depth reaches the set value Ls, hold the pressure for 5s and monitor the pressure decay rate ΔF / Δt during the pressure holding period; if ΔF / Δt>0.5kN / s, it is judged that the pressing is not in place or the elastic modulus of the material is insufficient, and the system marks it as a defective product; if it is qualified, proceed to the next step. S6. Overall aging vibration: Place the assembled guide semi-finished product on the resonance aging table, set the excitation frequency to f, so that the guide body resonates; continue to process in the resonance state for 15min-20min to eliminate the micro residual stress generated by press fitting. S7. Machining grooves: The guide after aging vibration treatment is machined by machining grooves. An annular groove or oil groove is cut at a specified position on the guide body. The groove depth tolerance is controlled within ±0.05mm, and the surface roughness of the groove wall Ra≤3.2μm. S8. Polishing treatment: Polish the surface of the guide after the groove, and use polishing paste to finely polish the end face of the mounting hole and the inner wall of the hole, so that the roughness Ra of the end face of the mounting hole is Ra≤0.8μm and the roughness Ra of the inner wall of the hole is Ra≤0.4μm. S9. Cleaning and Drying: After aging treatment, the guide is put into an ultrasonic cleaner and ultrasonically cleaned with a cleaning solution made of petroleum ether and isopropanol in a volume ratio of 4:1 for 3 minutes. Then, hot nitrogen gas at 120°C is introduced for purging and drying, and the residual moisture content M on the surface is detected by an infrared moisture meter. If M > 50 ppm, the drying time is extended by 30 seconds until M ≤ 50 ppm. S10. Final Inspection and Packaging: After drying, the guide is subjected to a final dimensional inspection. If it passes the inspection, it is sprayed with anti-rust oil and vacuum sealed.

[0005] The present invention is further configured such that: the guide body includes a body portion in the shape of a stepped shaft and a mounting hole opened on the body portion; the bushing is press-fitted into the mounting hole.

[0006] The invention is further configured such that: the opening of the mounting hole is chamfered, the chamfer angle is 15°-45°, for guiding the bushing during press fitting in S5; and the inner wall of the mounting hole has a spiral micro-texture after finishing, the spiral direction of the micro-texture is opposite to the rotation direction of the guide during operation, for increasing the adhesion of the lubricating oil film.

[0007] The invention is further configured such that: at least one annular oil storage groove is formed on the outer circular surface of the bushing, the cross-section of the annular oil storage groove is rectangular or arc-shaped, the groove depth is 0.2mm-0.5mm, and the groove width is 1.0mm-2.0mm; and several micro-pore channels connecting the annular oil storage groove and the inner hole are also provided in the wall thickness direction of the bushing, the micro-pore diameter is 0.1mm-0.3mm.

[0008] The present invention is further configured such that: in the dynamic determination of pressing and interference in S5, a temperature compensation mechanism is introduced: a thermocouple is embedded inside the pressing mold to monitor the instantaneous temperature rise ΔT of the pressing interface in real time; the temperature rise threshold is set to ΔTmax=15℃; if ΔT>ΔTmax is detected, it is determined that excessive frictional heat generation has caused material softening or adhesive wear, and the system immediately reduces the pressing speed V to 60% of the original speed and turns on the circulating coolant built into the mold for forced cooling. After ΔT falls back below ΔTmax, the pressing speed is restored to the original speed V to continue pressing.

[0009] The present invention is further configured such that: in the press-fitting process monitoring of S52, a segmented variable pressure control strategy is adopted: the pressing depth is divided into three segments, namely the inlet segment 0-L1, the interference segment L1-L2, and the final segment L2-Ls; in the inlet segment, low pressure P1 is used to press in at low speed V1, mainly for guiding purposes; when entering the interference segment, the system automatically switches to high pressure P2 and presses in at high speed V2 to improve production efficiency; when approaching 2mm before the final segment, the system switches to low pressure P1 and presses in at low speed V1 to prevent impact overload; if the actual pressure value in any segment deviates from the set pressure value by more than ±10%, it is determined that the segment is abnormal and the material return and refitting procedure is executed.

[0010] The present invention is further configured such that: in the overall aging vibration of S6, the excitation frequency f is not a fixed value, but adopts a frequency sweep mode: starting from 50Hz, the frequency is swept upward at a rate of 0.5Hz / s until the first natural frequency fn of the guide body is found; the frequency fn is locked for resonance aging processing; at the same time, during the processing, the vibration acceleration a is monitored by an acceleration sensor. If the peak fluctuation of a exceeds ±5%, the excitation force is dynamically adjusted to maintain the stability of the resonance state.

[0011] The present invention is further configured such that: the bushing press-fit pretreatment in S4 also includes a post-treatment step of laser microtexturing treatment: after the laser processing is completed, the micro-pit structure is subjected to low-pressure shot peening treatment with glass beads with a particle size of 0.05mm to remove the molten recast layer at the edge of the micro-pit; then the bushing is immersed in a nano-additive solution containing molybdenum disulfide, and the nano-additive is filled into the micro-pit and micro-pore channels by ultrasonic vibration, and then dried and cured at 80°C to form a solid lubricating film on the outer surface of the bushing.

[0012] The beneficial effects of this invention are: 1. Compared with existing technologies, the guide forming process of this invention significantly improves the finished product quality and reliability of the guide through precision machining and intelligent closed-loop control throughout the entire process. In the S3 precision machining stage, the flatness of the end face and the tolerance of the hole diameter are strictly controlled to ensure the high precision of the assembly datum, laying the foundation for subsequent press fitting. The displacement-pressure dual feedback sensor introduced in S5 constructs the press fitting force-displacement curve F(L), realizing dynamic monitoring of the press fitting process. By calculating the slope K and setting the fluctuation threshold, the system can accurately identify foreign objects or out-of-tolerance form and position on the mating surface, and immediately trigger reverse reversal and rework, avoiding the hidden damage caused by traditional rigid press fitting. Combined with the pressure decay rate monitoring in the holding pressure stage, it effectively eliminates scrap caused by improper press fitting or material defects. In addition, S9 uses a mixed solvent with a specific ratio for ultrasonic cleaning and hot nitrogen drying, combined with real-time monitoring by an infrared moisture meter, to ensure good cleanliness and dryness.

[0013] 2. In the guide molding process of this invention, the stepped shaft-shaped body design and the matching of the mounting holes not only optimize the structural strength but also facilitate precise positioning on automated production lines. By pressing the bushing into the preset mounting holes, modular manufacturing is achieved, which is beneficial for controlling the machining accuracy of key friction pairs. This structural design, combined with subsequent precision machining processes, enables the mounting holes to achieve H7 tolerance and Ra≤1.6μm surface quality after precision boring, ensuring the perpendicularity and coaxiality of the bushing during pressing. This structural design is closely integrated with the dynamic judgment logic in S5, allowing the displacement sensor data during the pressing process to accurately reflect the feed state of the bushing, rather than being affected by body deformation. The overall design reduces the machining difficulty, and the structural optimization enables intelligent monitoring of the assembly process, ensuring the stability and service life of the guide under high load conditions.

[0014] 3. In this invention, the 15°-45° chamfer at the mounting hole serves as a geometric guide for press-fitting, effectively reducing the risk of off-center loading in the initial stage of press-fitting. Combined with the dynamic judgment in S5, it reduces the scrap rate caused by "toothing" or jamming. The spiral micro-texture formed after the precision machining of the inner wall of the mounting hole has a spiral direction opposite to the rotation direction during operation. This precision machining feature utilizes the hydrodynamic effect, which can significantly increase the adhesion and load-bearing capacity of the lubricating oil film and prevent dry friction under boundary lubrication. This texture structure complements the micro-texturing treatment of the bushing in S4, jointly constructing an efficient oil storage and hydrodynamic lubrication system. Transforming the traditional smooth hole wall into a precision surface with hydrodynamic function greatly improves the wear resistance and anti-galling ability of the guide under high-speed rotation. Attached Figure Description

[0015] Figure 1 This is a flowchart of the process for manufacturing the guide of the present invention. Detailed Implementation

[0016] Reference Figure 1 The embodiments of the guide forming process of the present invention will be further described.

[0017] For ease of explanation, spatial relative terms such as “up,” “down,” “left,” and “right” are used in the embodiments to describe the relationship of one element or feature shown in the figures relative to another element or feature. It should be understood that, in addition to the orientations shown in the figures, spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figures is inverted, an element described as being “down” of other elements or features would be positioned “up” of those other elements or features. Therefore, the exemplary term “down” can encompass both up and down orientations. The device may be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0018] Moreover, relational terms such as “first” and “second” are used merely to distinguish one component from another that has the same name, without necessarily requiring or implying any such actual relationship or order between the components.

[0019] Figure 1 The guide forming process shown includes the following steps: S1. Prefabrication of accessories: The guide body and bushing are prepared separately; the guide body blank is prepared by powder metallurgy process: metal powder and binder are mixed according to the preset ratio, cold-pressed into green blank, and the green blank is degreased to obtain a prefabricated body suitable for subsequent sintering; the bushing blank is made of high lead-tin aluminum alloy or copper alloy tubing and rough-machined inside and outside. S2. Forming-Sintering-Shaping Process: The preform to be sintered is sent into the sintering furnace for high-temperature sintering, so that the metal powder is metallurgically bonded to form a dense guide body; then the sintered guide body is shaped and sized, and its external dimensions and form and position tolerances are corrected by mold, and internal stress is initially eliminated. S3. Precision machining of the guide body: The guide body is precision machined according to the design requirements. When the end face of the mounting hole is precision ground, the flatness error of the end face is ensured to be ≤0.01mm. Then the mounting hole is bored, and the hole diameter tolerance is controlled within the range of H7 grade, and the surface roughness Ra≤1.6μm. S4. Bushing press-fit pretreatment: Laser microtexturing is performed on the outer cylindrical surface of the bushing blank to form an array of micro-dimples, thereby increasing the contact surface area and oil storage capacity of the subsequent interference fit; at the same time, the inner hole of the bushing is honed to form a uniform cross-texture on its surface, with the cross-texture angle being 60°±5°. S5. Pressing and Dynamic Interference Determination: The pre-treated bushing is transported to the pressing station, and the target interference is set to α0; the servo press is started, and a displacement-pressure dual feedback sensor is integrated at the lower end of the press head. S51. Initial pressing judgment: When the pressing head contacts the upper surface of the bushing and applies a preload force Fp, if the actual displacement L1 fed back by the displacement sensor is less than the preset empty stroke L0, it is judged that the workpiece is not placed correctly and the system will stop and alarm; otherwise, it will enter the formal pressing process. S52. Pressing process monitoring: The press head presses downwards at a constant speed V, and the data of pressing force F and pressing depth L are collected in real time; a pressing force-displacement curve F(L) is constructed, and the slope of the curve K=dF / dL is calculated; if the fluctuation of the slope K in the pressing depth L∈[2mm,10mm] range exceeds ±15% of the initial slope K0, it is judged that there are foreign objects or the form and position tolerances are out of tolerance on the mating surface, the servo motor reverses and exits the bushing, and jumps to S4 to re-perform surface treatment; S53. Pressure Holding and Springback Judgment: When the pressing depth reaches the set value Ls, hold the pressure for 5s and monitor the pressure decay rate ΔF / Δt during the pressure holding period; if ΔF / Δt>0.5kN / s, it is judged that the pressing is not in place or the elastic modulus of the material is insufficient, and the system marks it as a defective product; if it is qualified, proceed to the next step. S6. Overall aging vibration: Place the assembled guide semi-finished product on the resonance aging table, set the excitation frequency to f, so that the guide body resonates; continue to process in the resonance state for 15min-20min to eliminate the micro residual stress generated by press fitting. S7. Machining grooves: The guide after aging vibration treatment is machined by machining grooves. An annular groove or oil groove is cut at a specified position on the guide body. The groove depth tolerance is controlled within ±0.05mm, and the surface roughness of the groove wall Ra≤3.2μm. S8. Polishing treatment: Polish the surface of the guide after the groove, and use polishing paste to finely polish the end face of the mounting hole and the inner wall of the hole, so that the roughness Ra of the end face of the mounting hole is Ra≤0.8μm and the roughness Ra of the inner wall of the hole is Ra≤0.4μm. S9. Cleaning and Drying: After aging treatment, the guide is put into an ultrasonic cleaner and ultrasonically cleaned with a cleaning solution made of petroleum ether and isopropanol in a volume ratio of 4:1 for 3 minutes. Then, hot nitrogen gas at 120°C is introduced for purging and drying, and the residual moisture content M on the surface is detected by an infrared moisture meter. If M > 50 ppm, the drying time is extended by 30 seconds until M ≤ 50 ppm. S10. Final inspection and packaging: After drying, the guide is subjected to a final dimensional inspection. If it passes the inspection, it is sprayed with anti-rust oil and vacuum-sealed. Through precision machining and intelligent closed-loop control throughout the entire process, the finished product quality and reliability of the guide are significantly improved. In the S3 precision machining stage, the flatness of the end face and the tolerance of the hole diameter are strictly controlled to ensure the high precision of the assembly datum, laying the foundation for subsequent press-fitting. The displacement-pressure dual feedback sensor introduced in S5 constructs the press-fitting force-displacement curve F(L), realizing dynamic monitoring of the press-fitting process. By calculating the slope K and setting the fluctuation threshold, the system can accurately identify foreign objects or out-of-tolerance form and position on the mating surface, and immediately trigger reverse reversal and rework, avoiding the hidden damage caused by traditional rigid press-fitting. Combined with the pressure decay rate monitoring in the holding pressure stage, the scrap caused by improper press-fitting or material defects is effectively eliminated. In addition, S9 uses a mixed solvent with a specific ratio for ultrasonic cleaning and hot nitrogen drying, combined with real-time monitoring by an infrared moisture meter, to ensure good cleanliness and dryness.

[0020] The guide body includes a stepped shaft-shaped body portion and a mounting hole formed on the body portion; the bushing is press-fitted into the mounting hole; The stepped shaft-shaped body design, combined with the mounting holes, not only optimizes structural strength but also facilitates precise positioning on automated production lines. Modular manufacturing is achieved by pressing the bushing into the pre-set mounting holes, which helps control the machining accuracy of key friction pairs. This structural design, coupled with subsequent precision machining processes, ensures that the mounting holes achieve H7 tolerance and Ra≤1.6μm surface quality after precision boring, guaranteeing the perpendicularity and coaxiality of the bushing during pressing. This structural design, closely integrated with the dynamic judgment logic in S5, ensures that the displacement sensor data during pressing accurately reflects the bushing's feed state, rather than being affected by body deformation. The overall design reduces machining difficulty, and structural optimization enables intelligent monitoring of the assembly process, ensuring the stability and service life of the guide under high-load conditions.

[0021] The mounting hole has a chamfer at the opening, with an angle of 15°-45°, which is used to guide the bushing during press-fitting in S5; and the inner wall of the mounting hole has a spiral micro-texture after finishing, with the spiral direction of the micro-texture opposite to the rotation direction of the guide during operation, which is used to increase the adhesion of the lubricating oil film. The 15°-45° chamfer at the mounting hole serves as a geometric guide for press-fitting, effectively reducing the risk of off-center loading in the initial stage of press-fitting. Combined with the dynamic judgment of S5, it reduces the scrap rate caused by "toothing" or jamming. The spiral micro-texture formed after the precision machining of the inner wall of the mounting hole has a spiral direction opposite to the rotation direction during operation. This precision machining feature utilizes the hydrodynamic effect, which can significantly increase the adhesion and load-bearing capacity of the lubricating oil film and prevent dry friction under boundary lubrication. This texture structure complements the micro-textured treatment of the bushing in S4, jointly constructing an efficient oil storage and hydrodynamic lubrication system. Transforming the traditional smooth hole wall into a precision surface with hydrodynamic function greatly improves the wear resistance and anti-galling ability of the guide under high-speed rotation.

[0022] At least one annular oil storage groove is formed on the outer circular surface of the bushing. The cross-section of the annular oil storage groove is rectangular or arc-shaped, with a groove depth of 0.2mm-0.5mm and a groove width of 1.0mm-2.0mm. Furthermore, several micro-pore channels connecting the annular oil storage groove and the inner hole are provided in the wall thickness direction of the bushing. The micro-pore diameter is 0.1mm-0.3mm. Through meticulous design of the bushing structure, lubrication and heat dissipation functions are enhanced. The annular oil reservoir on the outer circumference of the bushing and the microporous channels on the wall thickness constitute a three-dimensional oil-gas microcirculation system. During the press-fitting process, the microporous channels can serve as exhaust channels, reducing the air compression resistance in the enclosed space and making the press-fitting curve smoother, facilitating the accurate analysis of the slope K in step S52. Under working conditions, the lubricating oil stored in the annular oil reservoir can continuously permeate to the inner hole surface through the microporous channels, achieving self-lubrication and significantly reducing the coefficient of friction. This structural design, combined with the laser microtexturing treatment in S4, greatly increases the specific surface area of ​​the interference fit and improves the connection strength. At the same time, the microporous structure can absorb wear particles, avoiding scratches on the mating surfaces. This effectively solves the problems of easy burning and difficult maintenance of traditional bushings and extends the oil change cycle.

[0023] In the pressing and interference dynamic determination of S5, a temperature compensation mechanism is also introduced: a thermocouple is embedded inside the pressing mold to monitor the instantaneous temperature rise ΔT of the pressing interface in real time; the temperature rise threshold is set to ΔTmax=15℃; if ΔT>ΔTmax is detected, it is determined that excessive frictional heat generation has caused material softening or adhesive wear, and the system immediately reduces the pressing speed V to 60% of the original speed and turns on the circulating coolant built into the mold for forced cooling. After ΔT falls back below ΔTmax, the pressing speed is restored to the original speed V to continue pressing. By embedding thermocouples within the mold and capturing the instantaneous temperature rise ΔT at the press-fit interface in real time, the system can sensitively detect frictional heat generated by excessive interference fit or abnormal friction coefficient. When ΔT exceeds the 15℃ threshold, it is determined that the material may soften or experience adhesive wear, and the system immediately implements a combined control strategy of deceleration and forced cooling. This dynamic intervention not only prevents dimensional distortion of the guide body due to thermal expansion but also avoids the bushing losing its mechanical properties due to high-temperature annealing. This mechanism complements the press-fit force monitoring of S52, forming a "force-heat" dual closed-loop control. Compared to single pressure monitoring, temperature compensation better reflects the true physical state of the material interface, demonstrating the advantages of multi-physical quantity fusion diagnosis in intelligent manufacturing. This ensures that under high-speed production, each product can be assembled under optimal thermo-force coupling parameters, eliminating potential thermal failure hazards.

[0024] In the press-fitting process monitoring of S52, a segmented variable pressure control strategy is adopted: the pressing depth is divided into three segments, namely the inlet segment 0-L1, the interference segment L1-L2, and the final segment L2-Ls; in the inlet segment, low pressure P1 is used to press in at low speed V1, mainly for guiding purposes; when entering the interference segment, the system automatically switches to high pressure P2 and presses in at high speed V2 to improve production efficiency; when approaching 2mm before the final segment, the system switches to low pressure P1 and presses in at low speed V1 to prevent impact overload; if the actual pressure value in any segment deviates from the set pressure value by more than ±10%, it is determined that the fit of that segment is abnormal, and the material return and refitting procedure is executed; L1 and L2 are automatically calculated by the system based on the bushing inlet chamfer length and the interference fit segment length; By adopting a segmented variable pressure control strategy, high-precision and flexible control of the pressing process is achieved, balancing efficiency and quality. The pressing depth is scientifically divided into three stages: introduction, interference fit, and final position. Different pressure and speed parameters are matched to the mechanical characteristics of each stage. The low pressure and low speed of the introduction stage ensures smooth bushing placement and eliminates impact. The high pressure and high speed of the interference fit stage fully utilize the equipment efficiency and shorten non-value-added time. The deceleration and buffering of the final position stage effectively prevents the "bumping" effect and protects the precision-machined mounting hole end face. The system compares the pressure deviation of each stage in real time. Once it exceeds ±10%, it is judged as abnormal and the material is returned. This dynamic fault-tolerance mechanism greatly improves the robustness of the process. This strategy, combined with the idle stroke judgment of S51 and the slope analysis of S52, constructs a multi-dimensional pressing quality firewall, transforming the pressing process from a rough "push to the bottom" to a precise "apply force as needed", significantly improving the consistency of the interference fit and the reliability of the connection.

[0025] In the overall aging vibration of S6, the excitation frequency f is not a fixed value, but adopts a frequency sweep mode: starting from 50Hz, the frequency is swept upward at a rate of 0.5Hz / s until the first natural frequency fn of the guide body is found; the frequency fn is locked for resonance aging treatment; at the same time, during the treatment, the vibration acceleration a is monitored by an acceleration sensor. If the peak fluctuation of a exceeds ±5%, the excitation force is dynamically adjusted to maintain the stability of the resonance state. Through intelligent frequency sweep resonance technology, residual stress is precisely eliminated; it abandons the drawbacks of traditional fixed-frequency vibration, sweeping the frequency from 50Hz at a rate of 0.5Hz / s until the first natural frequency fn of the guide body is accurately captured, ensuring maximum energy transfer; locking fn for resonance aging can specifically release the microscopic residual stress generated during the pressing process, preventing the workpiece from deforming due to stress release during subsequent use; with real-time monitoring by an acceleration sensor, the system can dynamically fine-tune the excitation force to offset the effects of material damping changes and maintain the stability of the resonance peak; this dual closed-loop control based on frequency tracking and amplitude feedback is more energy-efficient, environmentally friendly, and highly efficient than manual aging or thermal aging; it ensures the stability of the internal structure of the guide, improves the long-term retention of dimensional accuracy, and demonstrates the ability to intelligently perceive and adaptively control physical field parameters in the later stages of precision manufacturing.

[0026] The pre-treatment of bushing pressing in S4 also includes a post-treatment process for laser microtexturing: after laser processing, the micro-pit structure is shot-peened with glass beads with a particle size of 0.05 mm to remove the molten recast layer at the edge of the micro-pit; then the bushing is immersed in a nano-additive solution containing molybdenum disulfide, and ultrasonic vibration is used to fill the micro-pits and micro-pore channels with the nano-additive, and then dried and cured at 80°C to form a solid lubricating film on the outer surface of the bushing. By employing laser post-processing and solid lubricant film curing technology, the bushing's fit performance and wear resistance life are significantly improved. After laser microtexturing, low-pressure shot peening is performed, using 0.05mm glass beads to remove the molten recast layer at the edges of micro-pits, restoring the activity of the metal matrix and ensuring the adhesion of subsequent coatings. Subsequently, the bushing is immersed in a nano-additive solution containing molybdenum disulfide and subjected to ultrasonic vibration, forcing the nanoparticles to fill the micro-pits and micropore channels. After drying and curing, a strong solid lubricant film is formed. This film provides excellent friction reduction and reduces ΔT temperature rise during the initial pressing stage. During service life, it serves as a secondary lubricant source, continuously releasing lubricant.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any ordinary changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A guide machining forming process characterized by: Includes the following steps: S1. Prefabrication of accessories: The guide body and bushing are prepared separately; the guide body blank is prepared by powder metallurgy process: metal powder and binder are mixed according to the preset ratio, cold-pressed into green blank, and the green blank is degreased to obtain a prefabricated body suitable for subsequent sintering; the bushing blank is made of high lead-tin aluminum alloy or copper alloy tubing and rough-machined inside and outside. S2. Forming-Sintering-Shaping Process: The preform to be sintered is sent into the sintering furnace for high-temperature sintering, so that the metal powder is metallurgically bonded to form a dense guide body; then the sintered guide body is shaped and sized, and its external dimensions and form and position tolerances are corrected by mold, and internal stress is initially eliminated. S3. Precision machining of the guide body: The guide body is precision machined according to the design requirements. When the end face of the mounting hole is precision ground, the flatness error of the end face is ensured to be ≤0.01mm. Then the mounting hole is bored, and the hole diameter tolerance is controlled within the range of H7 grade, and the surface roughness Ra≤1.6μm. S4. Bushing press-fit pretreatment: Laser microtexturing is performed on the outer cylindrical surface of the bushing blank to form an array of micro-dimples, thereby increasing the contact surface area and oil storage capacity of the subsequent interference fit; at the same time, the inner hole of the bushing is honed to form a uniform cross-texture on its surface, with the cross-texture angle being 60°±5°. S5. Pressing and dynamic determination of interference: The pre-treated bushing is transported to the pressing station, and the target interference is set as α0. Start the servo press and integrate a displacement-pressure dual feedback sensor at the lower end of the press head; S51. Initial pressing judgment: When the pressing head contacts the upper surface of the bushing and applies a preload force Fp, if the actual displacement L1 fed back by the displacement sensor is less than the preset empty stroke L0, it is judged that the workpiece is not placed correctly and the system will stop and alarm; otherwise, it will enter the formal pressing process. S52. Pressing process monitoring: The press head presses downwards at a constant speed V, and the data of pressing force F and pressing depth L are collected in real time; a pressing force-displacement curve F(L) is constructed, and the slope of the curve K=dF / dL is calculated; if the fluctuation of the slope K in the pressing depth L∈[2mm,10mm] range exceeds ±15% of the initial slope K0, it is judged that there are foreign objects or the form and position tolerances are out of tolerance on the mating surface, the servo motor reverses and exits the bushing, and jumps to S4 to re-perform surface treatment; S53. Pressure Holding and Springback Judgment: When the pressing depth reaches the set value Ls, hold the pressure for 5s and monitor the pressure decay rate ΔF / Δt during the pressure holding period; if ΔF / Δt>0.5kN / s, it is judged that the pressing is not in place or the elastic modulus of the material is insufficient, and the system marks it as a defective product; if it is qualified, proceed to the next step. S6. Overall aging vibration: Place the assembled guide semi-finished product on the resonance aging table, set the excitation frequency to f, so that the guide body resonates; continue to process in the resonance state for 15min-20min to eliminate the micro residual stress generated by press fitting. S7. Machining grooves: The guide after aging vibration treatment is machined by machining grooves. An annular groove or oil groove is cut at a specified position on the guide body. The groove depth tolerance is controlled within ±0.05mm, and the surface roughness of the groove wall Ra≤3.2μm. S8. Polishing treatment: Polish the surface of the guide after the groove, and use polishing paste to finely polish the end face of the mounting hole and the inner wall of the hole, so that the roughness Ra of the end face of the mounting hole is Ra≤0.8μm and the roughness Ra of the inner wall of the hole is Ra≤0.4μm. S9. Cleaning and Drying: After aging treatment, the guide is put into an ultrasonic cleaner and ultrasonically cleaned with a cleaning solution made of petroleum ether and isopropanol in a volume ratio of 4:1 for 3 minutes. Then, hot nitrogen gas at 120°C is introduced for purging and drying, and the residual moisture content M on the surface is detected by an infrared moisture meter. If M > 50 ppm, the drying time is extended by 30 seconds until M ≤ 50 ppm. S10. Final Inspection and Packaging: After drying, the guide is subjected to a final dimensional inspection. If it passes the inspection, it is sprayed with anti-rust oil and vacuum sealed.

2. A process for forming a stent according to claim 1 wherein, The guide body includes a stepped shaft-shaped body portion and a mounting hole formed on the body portion; the bushing is press-fitted into the mounting hole.

3. A process for forming a stent according to claim 2 wherein, The mounting hole has a chamfer at the opening, with an angle of 15°-45°, which is used to guide the bushing during press-fitting in S5; and the inner wall of the mounting hole has a spiral micro-texture after finishing, with the spiral direction of the micro-texture opposite to the rotation direction of the guide during operation, which is used to increase the adhesion of the lubricating oil film.

4. A process for forming a stent according to claim 1 wherein, At least one annular oil storage groove is formed on the outer circular surface of the bushing. The cross-section of the annular oil storage groove is rectangular or arc-shaped, with a groove depth of 0.2mm-0.5mm and a groove width of 1.0mm-2.0mm. Furthermore, several micro-pore channels connecting the annular oil storage groove and the inner hole are provided in the wall thickness direction of the bushing. The diameter of the micropores is 0.1mm-0.3mm.

5. The guide forming process according to claim 1, characterized in that, In the pressing and interference dynamic determination of S5, a temperature compensation mechanism is also introduced: a thermocouple is embedded inside the pressing mold to monitor the instantaneous temperature rise ΔT of the pressing interface in real time; the temperature rise threshold is set to ΔTmax=15℃; if ΔT>ΔTmax is detected, it is determined that excessive frictional heat generation has caused material softening or adhesive wear, and the system immediately reduces the pressing speed V to 60% of the original speed and turns on the circulating coolant built into the mold for forced cooling. After ΔT falls back below ΔTmax, the pressing speed is restored to the original speed V to continue pressing.

6. A process for forming a stent according to claim 1 wherein, In the press-fitting process monitoring of S52, a segmented variable pressure control strategy is adopted: the pressing depth is divided into three segments, namely the inlet segment 0-L1, the interference segment L1-L2, and the final segment L2-Ls; in the inlet segment, low pressure P1 is used to press in at low speed V1, mainly for guiding purposes; when entering the interference segment, the system automatically switches to high pressure P2 and presses in at high speed V2 to improve production efficiency; when approaching 2mm before the final segment, the system switches to low pressure P1 and presses in at low speed V1 to prevent impact overload; if the actual pressure value in any segment deviates from the set pressure value by more than ±10%, it is determined that the segment is abnormal and the material return and refitting procedure is executed.

7. A process for forming a stent according to claim 1 wherein, In the overall aging vibration of S6, the excitation frequency f is not a fixed value, but adopts a frequency sweep mode: starting from 50Hz, the frequency is swept upward at a rate of 0.5Hz / s until the first natural frequency fn of the guide body is found; the frequency fn is locked for resonance aging treatment; at the same time, during the treatment, the vibration acceleration a is monitored by an acceleration sensor. If the peak fluctuation of a exceeds ±5%, the excitation force is dynamically adjusted to maintain the stability of the resonance state.

8. A stent forming process as in claim 1, wherein, The pre-treatment of bushing pressing in S4 also includes a post-treatment process for laser microtexturing: after laser processing, the micro-pit structure is shot-peened with glass beads with a particle size of 0.05 mm to remove the molten recast layer at the edge of the micro-pit; then the bushing is immersed in a nano-additive solution containing molybdenum disulfide, and ultrasonic vibration is used to fill the micro-pits and micro-pore channels with the nano-additive, and then dried and cured at 80°C to form a solid lubricating film on the outer surface of the bushing.

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