On-line dressing method of grinding wheel and lead screw processing device

Abstract

This application relates to the field of high-precision planetary roller screw machining technology, and particularly to an online dressing method for grinding wheels and a screw machining device. The dressing method includes the step of inversely calculating the wear amount of the grinding wheel based on the change in the pitch diameter of the screw sample, including: real-time detection of the pitch diameter D1 of the screw sample; when the pitch diameter error value ΔD between D1 and the reference pitch diameter D2 of the screw sample exceeds a predetermined pitch diameter error threshold, then ΔR... max = (ΔD × tanθ) / 2; where ΔR max d is the maximum radius of the grinding wheel. (X) =d0+η×(ΔR) max -ΔR (X) ); where d (X) This invention relates to an online dressing method and lead screw processing device for grinding wheels, which aims to adjust the dressing depth at various axial positions of the grinding wheel. This method solves the problem of over-dressing / under-dressing caused by the inability of traditional online dressing methods to dynamically adapt to the wear gradient of the grinding wheel.

Description

Technical Field

[0001] This application relates to the field of high-precision planetary roller screw machining technology, and in particular to an online dressing method for grinding wheels and a screw machining device. Background Technology

[0002] The machining accuracy requirements for thin-walled deep-hole planetary roller screws used in military or humanoid robots are extremely high, and must be controlled at least within ±1μm.

[0003] In the existing machining process of thin-walled deep-hole planetary roller screws, the grinding wheel is used for machining. During machining, the grinding wheel is dressed in real time. However, the traditional method of online dressing of grinding wheels has the following problems:

[0004] Traditional online dressing methods for grinding wheels have a coarse control quantity, relying on fixed parameters for dressing and failing to dynamically adapt to the wear gradient of the grinding wheel, resulting in over-dressing or under-dressing. Summary of the Invention

[0005] The purpose of this application is to provide an online dressing method for grinding wheels and a lead screw machining device, thereby solving the problems of over-dressing / under-dressing caused by the coarse control quantity of traditional online dressing methods for grinding wheels, which rely on fixed parameters for dressing and cannot dynamically adapt to the wear gradient of the grinding wheel.

[0006] According to a first aspect of this application, an online dressing method for a grinding wheel is provided, wherein the grinding wheel is used to process a lead screw sample, and the grinding wheel can be dressed by a dressing wheel while processing the lead screw sample.

[0007] The online dressing method for the grinding wheel includes:

[0008] The wear of the grinding wheel can be inferred from the change in the mean diameter of the lead screw sample.

[0009] The steps for inferring the wear of the grinding wheel based on the change in the mean diameter of the lead screw sample include:

[0010] The pitch diameter D1 of the lead screw sample is detected in real time. When the pitch diameter error value ΔD between D1 and the reference pitch diameter D2 of the lead screw sample exceeds a predetermined pitch diameter error threshold, then the following condition is met:

[0011] ΔR max = (ΔD × tanθ) / 2; where ΔR max ΔD is the maximum radius of the grinding wheel, ΔD is the mean diameter error of the lead screw sample, and θ is the reference thread angle of the lead screw sample.

[0012] d (X) =d0+η×(ΔR) max -ΔR(X) ); where d (X) The dressing depth of the dressing wheel at various axial positions of the grinding wheel is given by the dressing wheel, d0 is the reference dressing depth of the dressing wheel, η is the gradient compensation coefficient, and ΔR is the dressing depth of the dressing wheel. (X) The radius is the radius at each position along the axial direction of the grinding wheel.

[0013] In any of the above technical solutions, the step of inferring the wear amount of the grinding wheel based on the change in the mean diameter of the lead screw sample further includes: calculating the evolution of the radius of the grinding wheel at various axial positions with space and time based on the physical mechanism of the wear of the grinding wheel during the grinding process using the component differential equation.

[0014] Among them, F n(x，t) V is the normal grinding force. (x，t) k is the linear velocity of the grinding wheel. p The wear rate coefficient of the grinding wheel.

[0015] In any of the above technical solutions, the online dressing method for the grinding wheel further includes: compensating for the wear of the grinding wheel in one step according to the material of the grinding wheel; the step of compensating for the wear of the grinding wheel in one step according to the material of the grinding wheel includes:

[0016] Δd error =β×(G / G0)×(B / B0)^γ;

[0017] Where, Δd error To compensate for the wear of the grinding wheel in one step, G is the actual grit size of the grinding wheel, G0 is the reference grit size of the grinding wheel, B is the binder hardness of the grinding wheel, B0 is the reference hardness of the grinding wheel, and β and γ are the material property correction coefficients of the grinding wheel.

[0018] Then, the total dressing depth d of the dressing wheel 总 =d (X) +Δd error .

[0019] In any of the above technical solutions, the online dressing method for the grinding wheel further includes: adjusting the dressing speed of the dressing wheel; the step of adjusting the dressing speed of the dressing wheel includes:

[0020] Real-time detection of the actual radial dressing force F of the dressing wheel real When F real Exceeding the target radial dressing force F target When the target radial trimming force threshold is reached, the following conditions are met:

[0021] Vnew =V old ×(F target / F real )^k; where V new V is the adjusted dressing speed of the dressing wheel. old The dressing speed F before the dressing wheel is adjusted. target F is the target radial dressing force for the dressing wheel. real The actual radial dressing force of the dressing wheel, k is the material damping coefficient of the grinding wheel.

[0022] In any of the above technical solutions, the online dressing method for the grinding wheel further includes: secondary compensation for the wear of the grinding wheel based on the fluctuation of the dressing force; the step of secondary compensation for the wear of the grinding wheel based on the fluctuation of the dressing force includes:

[0023] Δd=[α×(F real -F target )]-Δd error ;

[0024] Where Δd is the wear amount of the grinding wheel under secondary compensation, and α is the dressing force displacement conversion coefficient; then, the total dressing depth d of the dressing wheel is... 总 =d (X) +Δd.

[0025] According to a second aspect of this application, a lead screw machining apparatus is provided, comprising a grinding wheel, a dressing wheel, and a lead screw sample; the grinding wheel is used to machine the lead screw sample, and the grinding wheel can be dressed by the dressing wheel while machining the lead screw sample; the dressing wheel dresses the grinding wheel using the online dressing method of the grinding wheel as described above.

[0026] In any of the above technical solutions, the lead screw processing device further includes a lead screw pitch diameter measuring instrument; the lead screw pitch diameter measuring instrument detects the pitch diameter D1 of the lead screw sample in real time.

[0027] In any of the above technical solutions, the lead screw machining device further includes multiple force sensors; the multiple force sensors are spaced apart along one outer edge of the dressing wheel, and the multiple force sensors detect the radial dressing force of the dressing wheel in real time, and the average value of the multiple radial dressing forces detected by the multiple force sensors in real time is the actual radial dressing force F. (real) .

[0028] In any of the above technical solutions, the lead screw machining device further includes a first slide and a second slide; the first slide can drive the dressing wheel to move radially along the grinding wheel, and the second slide can drive the dressing wheel to move axially along the grinding wheel, so as to dress the grinding wheel.

[0029] In any of the above technical solutions, the lead screw machining device further includes a CNC system; the CNC system receives data sent by the force sensor and the lead screw pitch diameter measuring instrument, and calculates the data based on ΔR. max = (ΔD × tanθ) / 2, d (X) =d0+η×(ΔR) max -ΔR (X) ), Δd error =β×(G / G0)×(B / B0)^γ, Δd=[α×(F real -F target )]-Δd error ; Calculate the total dressing depth d at each axial position of the dressing wheel. 总 =d (X) +Δd, the CNC system determines the total dressing depth d at each axial position of the dressing wheel. 总 The first slide and the second slide are controlled to dress the grinding wheel;

[0030] During the trimming process, if the CNC system determines F real Exceeding the target radial dressing force F target When the target radial trimming force threshold is reached, according to V new =V old ×(F target / F real The adjusted dressing speed V of the dressing wheel is calculated using the formula )^k. new The CNC system adjusts the dressing speed V. new Control the speed of the dressing wheel to adjust to V new .

[0031] The online dressing method for grinding wheels in this application includes:

[0032] The wear of the grinding wheel is inferred from the change in the pitch diameter of the lead screw sample. Specifically, the pitch diameter D1 of the lead screw sample is monitored in real time. When the pitch diameter error ΔD between D1 and the reference pitch diameter D2 of the lead screw sample exceeds a predetermined pitch diameter error threshold, then the following condition is met:

[0033] ΔR max = (ΔD × tanθ) / 2; where ΔR maxΔD is the maximum radius of the grinding wheel, ΔD is the mean diameter error of the lead screw sample, and θ is the reference thread angle of the lead screw sample.

[0034] d (X) =d0+η×(ΔR) max -ΔR (X) ); where d (X) To dress the grinding wheel, the dressing depth is calculated at various axial positions of the grinding wheel. d0 is the reference dressing depth for dressing the grinding wheel, η is the gradient compensation coefficient, and ΔR... (X) This represents the radius at various axial positions of the grinding wheel.

[0035] Based on the above technical features, the beneficial effects of this application are as follows:

[0036] This application uses the mean diameter of the lead screw sample to reverse-engineer the wear of the grinding wheel, and dynamically corrects the dressing depth without stopping the machine. That is, firstly, based on ΔR... max = (ΔD×tanθ) / 2 calculates the maximum radius ΔR of the grinding wheel when the mean diameter error of the lead screw sample is too large. max .

[0037] Then, according to ΔR max -ΔR (X) Calculate the wear amount at each position along the axial direction of the grinding wheel.

[0038] Finally, according to d (X) =d0+η×(ΔR) max -ΔR (X) Calculate the dressing depth d of the dressing wheel at various axial positions of the grinding wheel. (X) .

[0039] As described above, this application uses the mean diameter of the lead screw sample to back-calculate the wear amount of the grinding wheel, and dynamically allocates the dressing depth without stopping the machine according to the wear gradient, so as to avoid over-dressing / under-dressing, adapt to complex grinding wheel wear, and ensure the consistency of the profile throughout the entire stroke.

[0040] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1A schematic diagram of the overall structure of the lead screw machining apparatus according to an embodiment of this application is shown;

[0043] Figure 2 Show Figure 1 Partial structural diagram;

[0044] Figure 3 Show Figure 2 Partial structural diagram;

[0045] Figure 4 A schematic diagram illustrating the assembly structure of the dressing electric spindle and dressing grinding wheel according to an embodiment of this application is shown.

[0046] Figure 5 This is a schematic diagram showing the assembly structure of the grinding electric spindle and grinding wheel according to an embodiment of this application.

[0047] Icons: 110 - Dressing electric spindle; 120 - Dressing grinding wheel; 210 - Grinding electric spindle; 220 - Grinding grinding wheel; 310 - First slide; 320 - Second slide; 400 - Force sensor; 500 - Leadscrew pitch diameter measuring instrument; 600 - Rotary table; 700 - Rotary table connecting plate; 800 - Guide rail; 900 - Leadscrew sample. Detailed Implementation

[0048] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, for clarity and brevity, descriptions of features known in the art may be omitted.

[0049] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0050] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, it may be directly "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, or there may be one or more other elements in between. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly bonded to" another element, "directly on" another element, or "directly covering" another element, there may be no other elements in between.

[0051] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0052] Although terms such as “first,” “second,” and “third” may be used herein to describe individual components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the examples described herein, the first component, assembly, region, layer, or part referred to as the second component, assembly, region, layer, or part may also be referred to as the second component, assembly, region, layer, or part.

[0053] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” are used herein to describe the relationship between one element and another, as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “upper” relative to another element will subsequently be “below” or “lower” relative to that other element. Therefore, the term “above” includes both “above” and “below” orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relation terms used herein will be interpreted accordingly.

[0054] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0055] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0056] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have a wide variety of constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application.

[0057] Prior to this application, the control parameters of traditional online dressing methods for grinding wheels were coarse, relying on fixed parameters for dressing and unable to dynamically adapt to the wear gradient of the grinding wheel, resulting in over-dressing or under-dressing.

[0058] In view of this, the first aspect of this application provides an online dressing method for grinding wheels, thereby solving the problem that the control quantity of traditional online dressing methods for grinding wheels is coarse, relies on fixed parameters for dressing, and cannot dynamically adapt to the wear gradient of the grinding wheel, resulting in over-dressing / under-dressing.

[0059] The following will describe in detail the lead screw machining apparatus of this application, and the online dressing method of the grinding wheel followed by the lead screw machining apparatus during the machining of the lead screw sample. The lead screw machining apparatus of this application includes a grinding wheel, a dressing wheel, and a lead screw sample. The grinding wheel is used to machine the lead screw sample, and can be dressed by the dressing wheel simultaneously with the machining of the lead screw sample. The online dressing method of this application can avoid over-dressing / under-dressing during the grinding wheel dressing process, adapt to complex grinding wheel wear, and ensure consistent profile throughout the entire stroke.

[0060] The online dressing method for grinding wheels in this application includes:

[0061] The wear of the grinding wheel is inferred from the change in the pitch diameter of the lead screw sample. Specifically, the pitch diameter D1 of the lead screw sample is monitored in real time. When the pitch diameter error ΔD between D1 and the reference pitch diameter D2 of the lead screw sample exceeds a predetermined pitch diameter error threshold, then the following condition is met:

[0062] ΔR max = (ΔD × tanθ) / 2; where ΔR maxΔD is the maximum radius of the grinding wheel, ΔD is the mean diameter error of the lead screw sample, and θ is the reference thread angle of the lead screw sample.

[0063] d (X) =d0+η×(ΔR) max -ΔR (X) ); where d (X) To dress the grinding wheel, the dressing depth is calculated at various axial positions of the grinding wheel. d0 is the reference dressing depth for dressing the grinding wheel, η is the gradient compensation coefficient, and ΔR... (X) This represents the radius at various axial positions of the grinding wheel.

[0064] It should be noted that the reference pitch diameter D2 can be understood as the target pitch diameter to be machined for the lead screw sample. Similarly, θ can be understood as the target thread angle to be machined for the lead screw sample; d0 can be understood as the initial fixed standard dressing depth designed based on the target to be machined for the lead screw sample.

[0065] In other words:

[0066] This application uses the mean diameter of the lead screw sample to reverse-engineer the wear of the grinding wheel, and dynamically corrects the dressing depth without stopping the machine. That is, firstly, based on ΔR... max = (ΔD×tanθ) / 2 calculates the maximum radius ΔR of the grinding wheel when the mean diameter error of the lead screw sample is too large. max .

[0067] Then, according to ΔR max -ΔR (X) Calculate the wear amount at each position along the axial direction of the grinding wheel.

[0068] Finally, according to d (X) =d0+η×(ΔR) max -ΔR (X) Calculate the dressing depth d of the dressing wheel at various axial positions of the grinding wheel. (X) .

[0069] As described above, this application uses the mean diameter of the lead screw sample to back-calculate the wear amount of the grinding wheel, and dynamically allocates the dressing depth without stopping the machine according to the wear gradient, so as to avoid over-dressing / under-dressing, adapt to complex grinding wheel wear, and ensure the consistency of the profile throughout the entire stroke.

[0070] It should be noted that the gradient compensation coefficient η takes the following values:

[0071] When the grinding wheel is a standard grinding wheel (WA60K), η = 0.4-0.6. When the grinding wheel is a CBN grinding wheel (B151), η = 0.25-0.35. When the grinding wheel is a diamond grinding wheel (SD3000), η = 0.15-0.25.

[0072] When ΔR (X) →ΔR max When, d should be satisfied (X) →d0 (reference trimming depth); when ΔR (X) When →0, d should be satisfied. (X) ≤1.2d0 (safety threshold).

[0073] Process validation indicators:

[0074] After dressing, the radial runout of the grinding wheel is ≤1μm; the surface roughness R of the ground workpiece is... a ≤0.4μm; grinding wheel life increased by ≥20% (compared to fixed compensation in existing technologies).

[0075] Optionally, in embodiments of this application, the step of calculating the wear amount of the grinding wheel based on the change in the mean diameter of the lead screw sample further includes:

[0076] Based on the physical mechanisms of grinding wheel wear during the grinding process (abrasive grain shedding, binder wear, clogging, etc.), the component differential equation is used to calculate the evolution of the radius of the grinding wheel at various axial positions with space and time. Specifically:

[0077] Among them, F n(x，t) V represents the normal grinding force (N), which is positively correlated with the material removal rate. (x，t) k is the linear velocity (m / s) of the grinding wheel. p This represents the wear rate coefficient of the grinding wheel (related to the hardness of the grinding wheel and the characteristics of the abrasive). From this, the radius ΔR at various axial positions of the grinding wheel can be derived. (X) And then according to d (X) =d0+η×(ΔR) max -ΔR (X) Calculate the dressing depth d of the dressing wheel at various axial positions of the grinding wheel. (X) .

[0078] It should be noted here that the wear rate coefficient k of the grinding wheel... p The possible values ​​are as follows:

[0079] Grinding wheel type Lead screw sample material <![CDATA[k p Range (×10) -8 mm / (N·m / s)]]> Alumina grinding wheel (WA60) 45# steel 3.2-5.6 CBN grinding wheel (B151) Titanium Alloy TC4 0.8-1.5 Diamond grinding wheel (SD3000) <![CDATA[Ceramic Al2O3]]> 0.2-0.4

[0080] It is also worth mentioning that the traditional online dressing method for grinding wheels adjusts the dressing amount only based on the grinding wheel profile model, ignoring the influence of grinding wheel material properties (such as binder hardness and particle size distribution).

[0081] In view of this, in order to solve the above-mentioned technical problems, the online dressing method for grinding wheels in the embodiments of this application further includes a step of compensating for the wear of the grinding wheel in one step according to the material of the grinding wheel, that is, adjusting according to the empirical formula of the grinding wheel material, as follows:

[0082] Trim deviation prediction model: Δd error =β×(G / G0)×(B / B0)^γ; where, Δd error To compensate for the wear of the grinding wheel in one pass, G is the actual grit size of the grinding wheel, G0 is the reference grit size of the grinding wheel, B is the binder hardness of the grinding wheel, B0 is the reference hardness of the grinding wheel, and β and γ are the material property correction coefficients of the grinding wheel.

[0083] Then, the total dressing depth d of the dressing wheel 总 =d (X) +Δd error .

[0084] It should be noted here that the material property correction factors β and γ for grinding wheels are taken as follows:

[0085] Grinding wheel type Binder type Particle size range β range γ range Alumina grinding wheel (WA) Ceramic binder 60-120# 0.8-1.2 1.3-1.6 CBN grinding wheel Metal binder 120-400# 1.5-2.0 0.9-1.2 Diamond grinding wheel resin binder 200-2000# 0.6-0.9 1.8-2.4

[0086] It should be noted here that G (actual granularity) means:

[0087] Definition: The actual abrasive grain size of the grinding wheel at present (usually expressed in "mesh" or "#", such as 60#, 120#), which characterizes the coarseness of the abrasive grains.

[0088] Function: Directly affects the cutting ability, surface roughness, and material removal rate of grinding wheels. Larger grit size (higher numerical value) results in finer abrasive grains, more cutting edges, and higher surface finish, but may reduce cutting efficiency.

[0089] G0 (Reference Granularity):

[0090] Definition: The theoretical reference grit size for grinding wheel design, usually based on the factory-specified value of the grinding wheel or the optimal grit size under ideal working conditions.

[0091] Function: Serves as a benchmark value for the compensation model, used to quantify the deviation between the actual granularity and the design target.

[0092] The meaning of the ratio G / G0:

[0093] Standardized compensation factor: By using the ratio of actual particle size to reference particle size, the influence of particle size variation on compensation amount is standardized, eliminating the differences between different grinding wheel models or batches.

[0094] Physical mechanism:

[0095] G>G0 (actual abrasive grains are finer): This may lead to a decrease in the cutting ability of the grinding wheel, and the dressing effect needs to be maintained by increasing the compensation amount (Δd).

[0096] G < G0 (the actual abrasive grains are coarser): The cutting ability is enhanced, and the compensation amount may be reduced to avoid over-trimming. Further, in the embodiments of the present application, the on-line dressing method of the grinding wheel further includes adjusting the dressing speed of the dressing wheel, specifically as follows:

[0097] Real-time detection of the actual radial dressing force F of the dressing wheel real , when F real exceeds the target radial dressing force F target of the target radial dressing force threshold F min or F max , then it satisfies:

[0098] V new = V old ×(F target / F real )^k;

[0099] Where, V new is the adjusted dressing speed of the dressing wheel, V old is the dressing speed of the dressing wheel before adjustment, F target is the target radial dressing force of the dressing wheel, F real is the actual radial dressing force of the dressing wheel, and k is the material damping coefficient of the grinding wheel. It should be noted here that the target radial dressing force F target can be understood as the initial fixed standard radial dressing force designed based on the target to be processed by the lead screw sample.

[0100] Set like this, the V real can be adjusted in real time according to the actual radial dressing force F new of the dressing wheel to prevent the dressing wheel from rotating too fast and causing equipment danger.

[0101] It should be noted here that the value of the material damping coefficient k of the grinding wheel is as follows:

[0102]

[0103] Further, in the embodiments of the present application, the on-line dressing method of the grinding wheel further includes adjusting the dressing parameters in real time based on the dressing force fluctuation, performing secondary compensation on the wear amount of the grinding wheel, and further performing secondary compensation on the dressing amount. Specifically as follows: ed]][[ID=]]

[0104] Δd = [α × (F real - F target )] - Δd error ; where, Δd is the wear amount of the secondary compensation grinding wheel, and α is the dressing force displacement conversion coefficient. Then, the total dressing depth d 总 = d (X) + Δd.

[0105] It should be noted that the values ​​of the trimming force-displacement conversion coefficient α are as follows:

[0106] Grinding wheel type Binder type Particle size range α range (μm / N) Alumina grinding wheel (WA) Ceramic binder 60-120# 0.08-0.15 CBN grinding wheel Metal binder 120-400# 0.05-0.12 Diamond grinding wheel resin binder 200-3000# 0.12-0.25 Electroplated CBN grinding wheels Electroplating binder D126-D251 0.03-0.08

[0107] In summary, the online dressing method for grinding wheels in this application includes:

[0108] According to ΔR max = (ΔD × tanθ) / 2, d (X) =d0+η×(ΔR) max -ΔR (X) ), Δd error =β×(G / G0)×(B / B0)^γ, Δd=[α×(F real -F target )]-Δd error ; Calculate the total dressing depth d at each axial position of the dressing wheel. 总 =d (X) +Δd.

[0109] During the trimming process, if the CNC system determines F real Exceeding the target radial dressing force F target When the target radial trimming force threshold is reached, according to V new =V old ×(F target / F real )^k calculates the dressing speed V after adjustment of the dressing wheel. new Then, based on the adjusted trimming speed V new Adjust the speed of the dressing wheel to V new .

[0110] According to a second aspect of this application, a lead screw machining apparatus is provided, comprising a grinding wheel 220, a dressing wheel 120, and a lead screw sample 900. The grinding wheel 220 is used to machine the lead screw sample 900, and the grinding wheel 220 can be dressed by the dressing wheel 120 simultaneously with the machining of the lead screw sample 900. The dressing wheel 120 dresses the grinding wheel 220 using the online dressing method for grinding wheels described above.

[0111] Specifically, the assembly relationship of the lead screw machining device in this application is as follows:

[0112] like Figures 1 to 5As shown, the lead screw machining device of this application can be detachably installed on an external thread grinding machine. The lead screw machining device includes a rotary table 600 that is detachably and fixedly connected to the guide rails on the grinding machine and can rotate around the A-axis. The central axis of the rotary table 600 is ensured to be at the same height as the central axis of the thin-walled deep-hole planetary roller lead screw. A rotary table connecting plate 700 that can be rotated and adjusted around the A-axis is fixedly connected to the rotary table 600. A detachable dressing electric spindle drive mechanism and a grinding electric spindle 210 are provided on the rotary table connecting plate 700. The dressing electric spindle drive mechanism is equipped with a dressing electric spindle 110 and a dressing grinding wheel 120. The dressing electric spindle drive mechanism includes a first slide 310 and a second slide 320 connected to each other. The first slide 310 can drive the dressing electric spindle 110 and the dressing grinding wheel 120 to move radially along the grinding wheel 220, and the second slide 320 can drive the dressing electric spindle 110 and the dressing grinding wheel 120 to move axially along the grinding wheel 220, so as to dress the grinding wheel 220.

[0113] In addition, such as Figure 2 and Figure 4 As shown, six evenly distributed force sensors 400 are installed on the dressing wheel 120 (the six evenly distributed force sensors 400 are mounted on...). Figure 4 At position C in the diagram, six force sensors 400 are spaced apart along one outer edge of the dressing wheel 120. These six force sensors 400 detect the radial dressing force of the dressing wheel 120 in real time. The average value of the multiple radial dressing forces detected by the six force sensors 400 in real time is the actual radial dressing force F. real .

[0114] like Figure 2 The grinding electric spindle 210 is equipped with a grinding wheel 220 and a lead screw pitch diameter measuring instrument 500, which detects the pitch diameter D1 of the lead screw sample 900 in real time.

[0115] The axes of the grinding wheel 220, the rotary table 600, and the lead screw sample 900 are at the same height. All components of this lead screw machining device move radially towards the lead screw sample 900 for both feed and retraction. Figure 1 As shown, the guide rail 800 at the bottom of the platform is slidably connected to the guide rail of the external thread grinding machine, and feeds and retracts in the radial direction of the lead screw sample 900 through the guide rail 800.

[0116] The grinding wheel dressing process is as follows:

[0117] The lead screw machining device of this application also includes a CNC system. The lead screw machining device of this application performs fully closed-loop automatic control of the grinding wheel dressing process through an integrated CNC system. The CNC system controls the dressing electric spindle drive mechanism to drive the dressing electric spindle and the dressing wheel to perform curved dressing movements of the grinding wheel along the radial and axial directions of the grinding wheel.

[0118] First, the CNC system receives data from the force sensor and the lead screw pitch diameter measuring instrument, and then calculates the result based on ΔR. max = (ΔD × tanθ) / 2, d (X) =d0+η×(ΔR) max -ΔR (X) ), Δd error =β×(G / G0)×(B / B0)^γ, Δd=[α×(F real -F target )]-Δd error Calculate the total dressing depth d at each axial position of the dressing wheel. 总 =d (X) +Δd.

[0119] Then, the CNC system calculates the total dressing depth d at each axial position of the dressing wheel. 总 The first slide 310 and the second slide 320 are controlled to dress the grinding wheel.

[0120] During the trimming process, if the CNC system determines F real Exceeding the target radial dressing force F target When the target radial trimming force threshold is reached, according to V new =V old ×(F target / F real )^k calculates the dressing speed V after adjustment of the dressing wheel. new The CNC system adjusts the dressing speed V. new Adjust the speed of the dressing wheel to V new .

[0121] In summary, this application provides an online dressing method for grinding wheels in a lead screw machining device. By inferring the wear amount of the grinding wheel from the mean diameter of the lead screw sample, and dynamically allocating the dressing depth without stopping the machine according to the wear gradient, the method avoids over-dressing / under-dressing, adapts to complex grinding wheel wear, and ensures consistent profile throughout the entire stroke.

[0122] This application addresses an online dressing method for grinding wheels in lead screw machining devices. By combining the aforementioned methods, it ensures ultra-high precision radial runout control of less than 1 micrometer during the machining of lead screw samples. The dressing method based on force-diameter dual closed-loop control is suitable for ultra-precision machining tasks, ensuring the accuracy of ultra-precision grinding of lead screw samples.

[0123] In addition, traditional online dressing methods for grinding wheels mostly rely on vision and acoustics (such as patent CN118905946B), but have the following limitations: vision sensors are easily contaminated by grinding fluid, require frequent maintenance, and are limited by optical resolution (±5μm); acoustic sensors such as AE sensors commonly used in electric spindles are often limited by acoustic accuracy and are more suitable for scenarios such as tool collision prediction.

[0124] This application addresses an online dressing method for grinding wheels in lead screw machining devices. By combining a force sensor (directly monitoring the dressing status) with a lead screw pitch diameter measuring instrument (indirectly providing feedback on grinding wheel wear), it overcomes the accuracy limitations of a single sensor, significantly improves accuracy, and has strong resistance to environmental interference.

[0125] This application addresses the quantification of material properties in an online dressing method for grinding wheels in lead screw machining devices: for the first time, grinding wheel grit size and binder composition are incorporated into the dressing amount prediction model, thereby improving the accuracy of micro-displacement compensation.

[0126] This application proposes a gradient dressing algorithm for an online dressing method of grinding wheels in a lead screw machining device: to address uneven axial wear of the grinding wheel, it achieves dynamic allocation of dressing depth, ensures consistency of the profile throughout the entire stroke, and solves the accuracy problem.

[0127] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in this application, or make equivalent substitutions for some of the technical features. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application.

Claims

1. A method for online dressing of grinding wheels, characterized in that, The grinding wheel is used to process the lead screw sample, and the grinding wheel can be dressed by the dressing wheel while processing the lead screw sample. The online dressing method for the grinding wheel includes: The wear of the grinding wheel can be inferred from the change in the mean diameter of the lead screw sample. The steps for inferring the wear of the grinding wheel based on the change in the mean diameter of the lead screw sample include: The pitch diameter D1 of the lead screw sample is detected in real time. When the pitch diameter error value ΔD between D1 and the reference pitch diameter D2 of the lead screw sample exceeds a predetermined pitch diameter error threshold, then the following condition is met: ΔR max =(ΔD×tanθ) / 2; Where, ΔR max ΔD is the maximum radius of the grinding wheel, ΔD is the mean diameter error of the lead screw sample, and θ is the reference thread angle of the lead screw sample. d (X) =d0+η×(ΔR max -ΔR (X) ); Where, d (X) The dressing depth of the dressing wheel at various axial positions of the grinding wheel is given by the dressing wheel, d0 is the reference dressing depth of the dressing wheel, η is the gradient compensation coefficient, and ΔR is the dressing depth of the dressing wheel. (X) The radius is the radius at each position along the axial direction of the grinding wheel.

2. The online dressing method for grinding wheels according to claim 1, characterized in that, The steps for calculating the wear of the grinding wheel based on the change in the mean diameter of the lead screw sample also include: Based on the physical mechanism of grinding wheel wear during the grinding process, the component differential equation is used to calculate the evolution of the radius of the grinding wheel at various axial positions with space and time. Among them, F n(x，t) V is the normal grinding force. (x，t) k is the linear velocity of the grinding wheel. p The wear rate coefficient of the grinding wheel.

3. The online dressing method for grinding wheels according to claim 2, characterized in that, The online dressing method for grinding wheels also includes: The wear of the grinding wheel is compensated once according to the material of the grinding wheel; The steps for compensating for the wear of the grinding wheel based on its material include: Δd error =β×(G / G0)×(B / B0)^γ; Where, Δd error To compensate for the wear of the grinding wheel in one step, G is the actual grit size of the grinding wheel, G0 is the reference grit size of the grinding wheel, B is the binder hardness of the grinding wheel, B0 is the reference hardness of the grinding wheel, and β and γ are the material property correction coefficients of the grinding wheel. Then, the total dressing depth d of the dressing wheel 总 =d (X) +Δd error .

4. The online dressing method for grinding wheels according to claim 3, characterized in that, The online dressing method for grinding wheels also includes: The dressing speed of the dressing wheel is adjusted; The steps for adjusting the dressing speed of the dressing wheel include: Real-time detection of the actual radial dressing force F of the dressing wheel real When F real Exceeding the target radial dressing force F target When the target radial trimming force threshold is reached, the following conditions are met: V new =V old ×(F target / F real )^k; Among them, V new V is the adjusted dressing speed of the dressing wheel. old The dressing speed F before the dressing wheel is adjusted. target F is the target radial dressing force for the dressing wheel. real The actual radial dressing force of the dressing wheel, k is the material damping coefficient of the grinding wheel.

5. The online dressing method for grinding wheels according to claim 4, characterized in that, The online dressing method for grinding wheels also includes: The wear of the grinding wheel is compensated twice based on the fluctuation of the dressing force; The steps for secondary compensation of the wear of the grinding wheel based on the fluctuation of the dressing force include: Δd=[α×(F real -F target )]-Δd error ; Where Δd is the wear amount of the grinding wheel under secondary compensation, and α is the dressing force displacement conversion coefficient; Then, the total dressing depth d of the dressing wheel 总 =d (X) +Δd.

6. A lead screw machining device, characterized in that, The lead screw processing device includes a grinding wheel, a dressing wheel, and a lead screw sample; The grinding wheel is used to process the lead screw sample, and the grinding wheel can be dressed by the dressing wheel while processing the lead screw sample. The dressing method for the grinding wheel adopts the online dressing method for grinding wheels as described in claim 5.

7. The lead screw machining device according to claim 6, characterized in that, The lead screw machining device also includes a lead screw pitch diameter measuring instrument; The lead screw pitch diameter measuring instrument detects the pitch diameter D1 of the lead screw sample in real time.

8. The lead screw machining device according to claim 7, characterized in that, The lead screw machining device also includes multiple force sensors; Multiple force sensors are spaced apart along one outer edge of the dressing wheel. These force sensors detect the radial dressing force of the dressing wheel in real time. The average value of the multiple radial dressing forces detected by the force sensors in real time is the actual radial dressing force F. real .

9. The lead screw machining device according to claim 8, characterized in that, The lead screw machining device also includes a first slide and a second slide; The first slide can drive the dressing wheel to move radially along the grinding wheel, and the second slide can drive the dressing wheel to move axially along the grinding wheel, so as to dress the grinding wheel.

10. The lead screw machining device according to claim 9, characterized in that, The lead screw machining device also includes a numerical control system; The CNC system receives data from the force sensor and the lead screw pitch diameter measuring instrument, and calculates the data based on ΔR. max = (ΔD × tanθ) / 2, d (X) =d0+η×(ΔR) max -ΔR (X) ), Δd error =β×(G / G0)×(B / B0)^γ, Δd=[α×(F real -F target )]-Δd error ; Calculate the total dressing depth d at each axial position of the dressing wheel. 总 =d (X) +Δd, the CNC system determines the total dressing depth d at each axial position of the dressing wheel. 总 The first slide and the second slide are controlled to dress the grinding wheel; During the trimming process, if the CNC system determines F real Exceeding the target radial dressing force F target When the target radial trimming force threshold is reached, according to V new =V old ×(F target / F real The adjusted dressing speed V of the dressing wheel is calculated using the formula )^k. new The CNC system adjusts the dressing speed V. new Control the speed of the dressing wheel to adjust to V new .

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