Method for improving antifriction and anti-climbing performance of sliding guide rail

Abstract

The invention discloses a method for improving antifriction and anti-climbing performance of a sliding guide rail, and belongs to the technical field of lubricating performance enhancement of sliding guide rails and surface treatment of machine tool guide rails. In order to solve the problems that a traditional guide rail is high in friction coefficient and prone to creeping, honeycomb regular hexagon pit microtextures which are arranged in a densest array mode are machined on the surface of a lower guide rail through laser, so that the microtextures form oil storage cavities, and the fluid dynamic pressure effect is generated; meanwhile, the surface of the upper sliding block is coated with an epoxy resin-based self-lubricating coating containing microcapsules, the microcapsules are broken along with friction to release lubricating oil, oil film distribution is perfected, the dry friction phenomenon is reduced, the oil film bearing capacity is improved by combining the fluid dynamic pressure effect brought by microtextures, and the antifriction and anti-creeping performance of the sliding guide rail is remarkably improved through the synergistic effect of the microcapsules and the microtextures. The technology effectively reduces friction coefficient fluctuation, inhibits a creeping phenomenon, prolongs the service life of the guide rail, and is suitable for scenes such as precision machine tools and heavy-load guide devices.

Description

Technical Field

[0001] This invention relates to a technology for improving the friction reduction and anti-climbing performance of sliding guideways. Through machine tool guideway surface treatment technology, laser micromachining, polishing, and the application of a self-lubricating coating are used to form a uniformly distributed hexagonal pit-like microtexture morphology on the surface of the lower guideway of the machine tool. The friction contact surface of the upper slider is coated with an epoxy resin-based coating containing microcapsules. Specifically, this invention relates to the application of pit-like microtexture guideway technology and microcapsule technology in machine tool guideways. Background Technology

[0002] With the advancement of technology, the demand for complex and precision parts has increased significantly, making precision machine tools crucial in the machinery manufacturing industry. As a key component for support and guidance in precision equipment, the sliding guide rail's operational quality directly determines the equipment's motion accuracy, working efficiency, and stability. This is especially critical in scenarios with extremely high precision requirements, such as CNC machine tools, high-speed machining centers, and automated measuring equipment, where the service stability of the sliding guide rail is paramount. However, because the guide rail is often in a boundary lubrication state during start-up, shutdown, or low-speed sliding, traditional guide rail structures are prone to "creeping," where the small displacements of the guide rail slider are discontinuous, resulting in momentary jamming or jumping, severely affecting positioning accuracy and the quality of the machined surface. The "creeping" phenomenon is not only affected by macroscopic factors such as contact materials, load, and lubricant type, but also closely related to the microstructure of the guide rail surface. By machining surface texture and adjusting the microtexture distribution in the friction contact area of ​​the lower guide rail, oil reservoirs and pressure buffer zones can be formed in localized areas, effectively regulating the distribution and flow of lubricating oil, thereby improving the anti-creep performance of the sliding guide rail. The epoxy resin-based self-lubricating coating containing microcapsules releases core lubricating oil as the microcapsules rupture with wear, reducing the dry friction contact area during actual operation of the guide rail and thus improving the low-friction performance of the sliding guide rail. Through the synergistic effect of the texture and the self-lubricating coating, the friction-reducing and anti-creep performance of the sliding guide rail is enhanced.

[0003] Chinese patent CN102678751A discloses a sliding guide rail with micro-pitted oil pockets on the substrate surface. The guide rail substrate has uniformly distributed micro-pitted oil pockets, and then a layer of soft material is bonded to the substrate. Although the lubrication effect of the guide rail is improved, the soft material will undergo plastic deformation under the load of the worktable and slider, which will directly affect the surface quality of the machined parts; furthermore, the adhesion between the soft material and the guide rail substrate material is difficult, and the soft material is prone to detachment.

[0004] Chinese patent CN101117654A uses a guide rail quenching process to improve the wear resistance of the guide rail, but the crawling phenomenon and lubrication performance of the guide rail are not improved, and the overall performance of the machine tool guide rail cannot be improved. Even if the overall performance of the rolling guide rail used in high-precision machine tools is improved, the guide rail has a complex structure, is inconvenient to maintain, has high manufacturing costs, and is not economically viable.

[0005] Studies by Ren N and Zhu D et al. have shown that the distribution, orientation, length ratio, and shape of microtextures significantly affect lubrication performance. Experimental studies by Wang Wenzhong et al. have demonstrated that the depth, area ratio, and size of micropores have a significant impact on friction performance, while research by Shen Dian et al. indicates that the spacing of micropits is also an important influencing factor. Therefore, proposing a microtexture type with good technical effects is of great significance for improving the working performance of guideways.

[0006] Chinese patent CN117563521A discloses a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule and its preparation method. This microcapsule possesses excellent density and tribological properties, achieving lubrication and friction reduction effects, and can provide guidance for the application of microcapsule self-lubricating coatings in sliding guide rail applications.

[0007] Among various microtextural morphologies, the traditionally used circular pits, rectangular grooves, and triangular grooves, while achieving some lubrication improvement in experiments, suffer from low effective oil capacity per unit area due to limitations in their arrangement. Furthermore, the oil film continuity in the sliding direction is insufficient, making it difficult to maintain stable dynamic pressure under complex loading and variable speed conditions. Meanwhile, research also indicates that, under the same pit duty cycle, hexagonal morphologies with longer geometrical contact sides are more conducive to shear zone formation and uniform lubricant diffusion, thereby improving overall dynamic pressure performance. Currently, there is no research on applying microcapsule self-lubricating coatings to sliding guides; however, numerous experimental studies have shown that microcapsule self-lubricating coatings have good friction-reducing properties.

[0008] It is evident that existing technologies and research need to be further developed and improved in the synergistic application of microtexture technology and microcapsule technology to enhance the friction reduction and anti-creep performance of sliding guide rails. Summary of the Invention

[0009] This invention addresses the issues of high friction coefficient, easy wear, and creeping phenomena on the working surface of guide rails. It proposes a technology that improves the friction reduction and anti-creep performance of sliding guide rails based on the synergistic effect of regular hexagonal pit microtexture and epoxy resin-based microcapsule self-lubricating coating.

[0010] The technical solution adopted in this invention is as follows: a regular hexagonal pit microtextured guide rail and an epoxy resin-based microcapsule self-lubricating coating, wherein regular hexagonal pit microtextures are regularly constructed on the working surface of the lower guide rail, such as... Figure 1 As shown, the pits are arranged in a honeycomb array, and an epoxy resin-based microcapsule self-lubricating coating is applied to the working surface of the upper guide rail slider.

[0011] In the above scheme, the circumcircle diameter of each regular hexagonal pit is d=100μm, the depth is h=10μm, the morphological spacing is L=273μm, and the corresponding texture area occupancy rate is 10.06%. Figure 2 As shown. The area occupancy rate is the ratio of the sum of the areas of the micro-dimples to the area of ​​the guide rail surface occupied by the micro-dimple texture distribution.

[0012] The use of microtextures of the above dimensions is beneficial for improving the oil film's resistance and maintaining a high dynamic pressure effect.

[0013] In the above scheme, the microcapsules account for 10% of the mass fraction of the epoxy resin-based coating, the wall material is polysulfone, and the core material is lubricating oil. Figure 4 As shown.

[0014] By using microcapsules with the above-mentioned content, while ensuring the tensile and compressive mechanical properties of the coating, good self-lubricating properties can be maintained, effectively reducing the friction coefficient and wear rate of the guide rail.

[0015] The specific steps to implement the present invention include the following: Step 1: Design the microtexture morphology of the guide rail surface, select the micro-dimple texture shape, and determine the area occupancy rate of the regular hexagonal micro-dimples. The area occupancy rate is the ratio of the sum of the areas of the micro-dimples to the area of ​​the guide rail surface occupied by the micro-dimple texture distribution.

[0016] Step 2: The guide rail surface undergoes a pretreatment grinding process to ensure that the surface roughness and geometric tolerances meet the requirements of laser micro-machining.

[0017] Step 3: Clean the surface of the guide rail with acetone and wipe it with a dry cotton cloth until it is shiny and dust-free, removing surface dust and oil.

[0018] Step 3: A diode-pumped YAG laser is used. The laser processing parameters are: laser wavelength 532nm or 1064nm, defocusing amount [-1.2, 1.2]mm, pulse width 0.5ms, pulse frequency 1-10kHz, and laser energy density 10 4 -10 6 W / cm 2 The auxiliary gas is nitrogen, and the blowing angle of the auxiliary gas is 0°-60° with the normal of the workpiece.

[0019] Step 4, post-processing of laser micro-machining: polishing is performed on the guide rail surface to remove a small amount of slag generated during laser processing of micro-pits, resulting in an array of micro-pit morphology. The polishing process parameters are: resin as binder, green carbonized material, soft abrasive strips with a particle size of 1500#, pressure of 0.8-1.0MPa, and time of 10-25s.

[0020] Step 5: After polishing, scrape the surface of the lower guide rail until it meets the requirements. When the surface roughness parameter Ra≤0.1μm, and the straightness and flatness are both ≤0.01μm, the scraping can be stopped, and the surface processing of the lower guide rail is completed.

[0021] Step 6: Clean the working surface of the slider. The working surface of the slider to be formed must not be affected by oil, grease, dust, rust, or protective paint. Clean the working surface multiple times before coating. Use acetone to clean before coating, and then use compressed air to clean the forming surface to ensure that the coating can better adhere to the working surface.

[0022] Step 7: Roughen the working surface of the slider. The guide rail forming surface needs to be roughened by rough planing, rough turning, wire cutting and other processing methods to make the forming surface rougher, increase the adhesion of the coating and make it easier to apply the coating material.

[0023] Step 8: Seal the boundary of the working surface of the slider to be formed. Depending on the characteristics of the workpiece, the main sealing methods are metal boundary sealing and rubber sealing. Sometimes, soft tape is also used for sealing.

[0024] Step 9: Position the slider to be formed by fixing the cleaned guide surface with screws or clamps. This ensures a uniform coating thickness and prevents uneven coating thickness caused by pressure generated during the process.

[0025] Step 10: Prepare the coating material by uniformly preparing the epoxy resin-based coating and microcapsules in a certain proportion to obtain a usable coating material.

[0026] Step 11, spray release agent: spray release agent on the surface of the molding die or on the surface where the coating may overflow.

[0027] Step 12, Coating: Apply coating material to the roughened and cleaned slider surface.

[0028] Step 13, molding: Press the molding mold cover onto the slider contact surface. After the guide rail coating is cured, the molding mold can be easily peeled off from the guide rail coating to obtain a slider with coating.

[0029] Step 14: Post-demolding processing and cleaning. Polish the coated surface of the demolded slider to ensure that the surface roughness, flatness, and straightness meet the requirements. Then clean the slider surface with acetone and wipe it with a dry cotton cloth until it is shiny and dust-free, removing surface dust and oil.

[0030] This invention also provides a method for reducing the surface friction coefficient of a microtextured guide rail or for extending the service life of a microtextured guide rail. This method uses the aforementioned microtextured guide rail, with lubricant filled into the microtexture.

[0031] The lubricating oil is 32# guide rail lubricating oil.

[0032] Through the above technical solution, the guide rail can store lubricating oil inside the recesses during actual operation. During sliding, shear stress drives the microcapsules to rupture, achieving dynamic release and distribution of the oil, thereby establishing a stable fluid lubricating oil film. Compared to traditional untextured or uncoated surfaces, this invention can achieve higher dynamic pressure response over a wider speed range, significantly reducing friction coefficient fluctuations and creep amplitude. Furthermore, the recess array also has a certain debris collection function, helping to keep the contact surface clean and extend the service life of the guide rail.

[0033] This invention not only takes into account both tribological functionality and load-bearing capacity requirements in its structural design, but also fully considers manufacturing feasibility and engineering applicability. It is applicable to various precision linear guides, heavy-duty guide devices, and high-speed dynamic platforms. It is an effective way to solve the current problem of friction and vibration control of sliding guides and has broad application prospects and promotion value. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a guide rail structure with microtexture.

[0035] In this diagram, 1 represents the upper guide rail slider, 2 represents the lower guide rail, and 3 represents the microtexture on the guide rail.

[0036] Figure 2 This is a schematic diagram of the microtexture morphology of the regular hexagonal recesses on the lower guide rail.

[0037] Among them, 2 is the lower guide rail, and 3 is the microtexture on the guide rail.

[0038] Figure 3 This is a schematic diagram of the densest arrangement of the hexagonal recessed micro-textured honeycomb structure on the lower guide rail.

[0039] Among them, 3 represents the hexagonal pit microtexture on the guide rail.

[0040] Figure 4 This is a schematic diagram of the microcapsule structure.

[0041] Figure 5 This is a schematic diagram of the surface structure of the slider after surface roughening treatment.

[0042] Figure 6 This is a diagram of a rectangular guide rail with a microtextured morphology of regular hexagonal pits.

[0043] Among them, 4 is the upper guide rail slider of the rectangular guide rail, and 5 is the lower guide rail of the rectangular guide rail.

[0044] Figure 7 A diagram of a triangular guide rail with a microtextured morphology of regular hexagonal pits.

[0045] Among them, 6 is the upper guide rail slider of the triangular guide rail, and 7 is the lower guide rail of the rectangular guide rail.

[0046] Figure 8 A diagram of a dovetail-shaped guide rail with a microtextured morphology of regular hexagonal pits.

[0047] Among them, 8 is the upper guide rail slider of the dovetail-shaped guide rail, and 9 is the lower guide rail of the rectangular guide rail.

[0048] Figure 9 The diagram shows the test results for the frictional properties and anti-creep performance of the microtextured guide rail. Detailed Implementation

[0049] The following description uses a precision gantry lathe guide rail as an example to illustrate the specific implementation of the present invention.

[0050] The laser processing equipment uses a diode-pumped YAG laser.

[0051] Precision gantry lathe guide rail, guide rail material HT200, guide rail type is rectangular sliding guide rail. Example

[0052] The steps are as follows: Step 1, for a precision gantry lathe, the guide rail type is a rectangular sliding guide rail, such as... Figure 6 As shown. The microtexture morphology consists of regular hexagonal pits. Specific microtexture parameters are: circumcircle diameter of the regular hexagonal pit texture is d = 100 μm, depth is h = 10 μm, morphology spacing is L = 273 μm, and the corresponding texture area occupancy is 10.06%, arranged in a honeycomb-like dense pattern, as shown. Figure 3 As shown.

[0053] Step 2: Before laser micromachining, the guide rail surface needs to undergo a pre-treatment process, which involves grinding to ensure that the guide rail surface meets the requirements of laser micromachining.

[0054] Step 3: A diode-pumped YAG laser is used. The laser processing parameters are: laser wavelength 532nm or 1064nm, defocusing amount [-1.2, 1.2]mm, pulse width 0.5ms, pulse frequency 1-10kHz, and laser energy density 10 4 -10 6 W / cm 2 The auxiliary gas is nitrogen, and the blowing angle of the auxiliary gas is 0°-60° with the normal of the workpiece.

[0055] Step 4, post-processing of laser micro-machining: polishing is performed on the guide rail surface to remove a small amount of slag generated during laser processing of micro-pits, resulting in an array of micro-pit morphology. The polishing process parameters are: resin as binder, green carbonized material, soft abrasive strips with a particle size of 1500#, pressure of 0.8-1.0MPa, and time of 10-25s.

[0056] Step 5: After polishing, scrape the surface of the lower guide rail until it meets the requirements. When the surface roughness parameter Ra≤0.1μm, and the straightness and flatness are both ≤0.01μm, the scraping can be stopped, and the surface processing of the lower guide rail is completed.

[0057] Step 6: Clean the working surface of the slider. The working surface of the slider to be formed must not be affected by oil, grease, dust, rust, or protective paint. Clean the working surface multiple times before coating. Use acetone to clean before coating, and then use compressed air to clean the forming surface to ensure that the coating can better adhere to the working surface.

[0058] Step 7: Roughen the working surface of the slider. The guide rail forming surface needs to be roughened by methods such as rough planing, rough turning, and wire cutting to create a relatively rough forming surface. Figure 5 As shown.

[0059] Step 8: Seal the boundary of the working surface of the slider to be formed. Depending on the characteristics of the workpiece, the main sealing methods are metal boundary sealing and rubber sealing. Sometimes, soft tape is also used for sealing.

[0060] Step 9: Position the slider to be formed by fixing the cleaned guide surface with screws or clamps. This ensures a uniform coating thickness and prevents uneven coating thickness caused by pressure generated during the process.

[0061] Step 10: Prepare the coating material by uniformly preparing the epoxy resin-based coating and microcapsules in a certain proportion to obtain a usable coating material.

[0062] Step 11, spray release agent: spray release agent on the surface of the molding die or on the surface where the coating may overflow.

[0063] Step 12, Coating: Apply coating material to the roughened and cleaned slider surface.

[0064] Step 13, molding: Press the molding mold cover onto the slider contact surface. After the guide rail coating is cured, the molding mold can be easily peeled off from the guide rail coating to obtain a slider with coating.

[0065] Step 14: Post-demolding processing and cleaning. Polish the coated surface of the demolded slider to ensure that the surface roughness, flatness, and straightness meet the requirements. Then clean the slider surface with acetone and wipe it with a dry cotton cloth until it is shiny and dust-free, removing surface dust and oil. Example

[0066] Example 2, as Figure 7 As shown, the regular hexagonal recessed microtexture of the present invention is applied to the lower guide rail 7 of the triangular guide rail, and 6 corresponds to the guide rail slider of the triangular guide rail. Example

[0067] Example 3, as Figure 8 As shown, the regular hexagonal recessed microtexture of the present invention is applied to the lower guide rail 9 of the dovetail-shaped guide rail, and 8 corresponds to the guide rail slider of the dovetail-shaped guide rail.

[0068] The above examples are merely illustrative of the present invention and are not intended to limit the invention. Any modifications or alterations made to the present invention should be within the scope of protection of the present invention.

[0069] Comparative Example 1; Comparative Example 1: The guide rail is made of HT200 cast iron. The surface of the lower guide rail is free of microtexture. The upper guide rail slider is coated with an epoxy resin coating that does not contain microcapsules. The lubricating medium is 32# lubricating oil, which is denoted as 0%wt-no-texture group.

[0070] Performance testing; Taking a rectangular guide rail as an example, the microtexture and coating using the above parameters are denoted as the 10%wt-10.06% microtexture group. Under the same test conditions, the friction performance and anti-creep performance of the microtextured guide rail were tested experimentally, and the results are as follows. Figure 9 As shown: The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A structure for improving the friction reduction and anti-climbing performance of a sliding guide rail, characterized in that, A honeycomb-shaped array of regular hexagonal pits is machined on the working surface of the lower guide rail of the sliding guide rail, while an epoxy resin-based self-lubricating coating containing microcapsules is coated on the working surface of the upper guide rail slider.

2. The sliding guide rail friction reduction and anti-climb performance improvement structure according to claim 1, characterized in that, The circumscribed circle of the regular hexagonal pit microtexture has a diameter of 100 μm, a depth of 10 μm, and a morphological spacing of 273 μm. It adopts the densest honeycomb arrangement, and the texture area occupies 10.06%. The area occupancy rate is the ratio of the sum of the areas of the micropits to the area of ​​the guide rail surface occupied by the micropit texture distribution.

3. The sliding guide rail friction reduction and anti-climb performance improvement structure according to claim 1, characterized in that, The hexagonal pit microtexture is polished and then scraped to the required precision, with a surface roughness parameter Ra≤0.1μm, and straightness and flatness both≤0.01μm.

4. The sliding guide rail friction reduction and anti-climb performance improvement structure according to claim 1, characterized in that, The self-lubricating coating contains 10% microcapsules by mass, with the wall material of the microcapsules being polysulfone and the core material being lubricating oil.

5. A method for reducing the surface friction coefficient of a sliding guide rail, characterized in that, This method employs the sliding guide rail with microtexture as described in claim 1, wherein the microtexture is filled with lubricant.

6. The method for reducing the surface friction coefficient of a composite guide rail as described in claim 5, characterized in that, The lubricant is 32# guide rail lubricating oil.

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