A precision grinding damage prevention processing method for coated saw blade

Abstract

This invention relates to the field of precision machining technology and discloses a method for preventing damage during precision grinding of coated saw blades. The method includes: pre-treating the coated saw blade and correcting radial runout; calculating the critical grinding speed and critical grinding depth based on the intrinsic parameters of the coating material, and limiting the machining parameters within a safe range; implementing constant temperature and high pressure jet cooling; collecting elastic stress waves in the grinding arc region using an acoustic emission sensor, and calculating the statistical average and standard deviation of the root mean square value after wavelet transform noise reduction and reconstruction to construct a dynamic damage monitoring threshold; when the signal amplitude exceeds the limit, the machine tool servo system automatically performs machining parameter degradation intervention; after machining, the coating integrity is detected, and damaged parts are transferred to a closed loop of decoating and recoating. This method solves the problems of blurred physical boundaries, low monitoring reliability, and lack of subcritical damage intervention in the grinding of coated saw blades.

Description

Technical Field

[0001] This invention relates to the field of precision machining technology, specifically to a precision grinding and damage-preventing machining method for coated saw blades. Background Technology

[0002] Coated saw blades play a crucial role in modern, high-efficiency metal cutting. The dual-layer design of the hard coating and tough substrate aims to balance wear resistance and impact resistance. During precision grinding and regrinding of coated saw blades, the coating-substrate system simultaneously withstands the instantaneous high-frequency impact of grinding forces and the intense, continuous accumulation of grinding heat.

[0003] Coating failure during grinding follows two pathways. The first is the mechanical damage pathway: when the thickness cut by a single abrasive grain is too large, causing the transient stress within the coating or at the interface to exceed the critical load allowed by the coating material's fracture toughness, microcracks will initiate and propagate radially, ultimately resulting in coating peeling. The second is the thermal damage pathway: when the grinding speed is too high, and the heat injection rate in the grinding area is much greater than the heat dissipation rate of the coating-substrate system and coolant, localized transient high temperatures will exceed the oxidation resistance limit or phase transition point of the coating material, leading to thermal discoloration, lattice damage, and thermal stress delamination.

[0004] Current processing parameters are essentially undefined, relying on trial and error based on experience, which can easily lead to exceeding safety boundaries and causing damage. Existing online monitoring threshold setting logic generally uses either an absolutely fixed threshold or a certain percentage of the initial extreme value as the alarm threshold. Because the grinding process is accompanied by severe normal background noise, this threshold setting scheme, lacking statistical support, easily misinterprets the Gaussian white noise peaks of normal cutting as damage signals, causing the machine tool to frequently trigger erroneous interventions and preventing stable and continuous operation in industrial settings.

[0005] The system typically shuts down passively after macroscopic damage occurs, and is unable to adaptively degrade parameters in the early stages of roughness degradation, lacking the ability to detect subcritical damage. Summary of the Invention

[0006] The purpose of this invention is to provide a precision grinding and damage prevention method for coated saw blades, which solves the technical problem of irreversible damage to the coating caused by the fuzzy physical boundaries, lack of statistical support for the setting of monitoring thresholds, and lack of subcritical damage perception capability in the existing coated saw blade grinding process.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A precision grinding and damage-preventing machining method for coated saw blades includes the following steps:

[0009] Step 1: Perform physical and chemical pretreatment on the coated saw blade to remove mechanical impurities and chemical oxide layers adhering to the surface of the coated saw blade;

[0010] Step 2: Install the pre-treated coated saw blade onto the spindle of a precision grinding machine and perform dynamic radial runout detection and eccentricity correction to constrain the radial runout value of the coated saw blade within the preset tolerance range.

[0011] Step 3: Extract the tensile strength of the coating material and the density of the matrix material of the coated saw blade. Combine this with the grinding speed influence coefficient to calculate the critical grinding speed that will not cause thermal stress delamination at the coating interface. Set the actual grinding speed to within 60% to 80% of this critical grinding speed. Extract the critical stress coefficient of the coating material, coating thickness, and matrix material density of the coated saw blade. Combine this with the actual grinding speed to calculate the critical grinding depth that will not cause micro-mechanical fracture of the coating. Set the actual grinding depth to within 30% to 50% of this critical grinding depth.

[0012] Step 4: During the precision grinding cycle, start the coolant circulation system to perform constant temperature high-pressure jet cooling on the grinding wedge contact area;

[0013] Step 5: Deploy acoustic emission sensors to acquire the elastic stress wave state of the grinding arc zone in real time; within the initial stable cutting window where no coating damage occurs, perform wavelet transform noise reduction on the acquired acoustic emission signal, extract high-frequency detail coefficients of the mapped coating lattice fracture frequency band for signal reconstruction, use the root mean square value of the reconstructed signal as the quantization benchmark of the acoustic emission signal amplitude, and calculate the statistical average value of this benchmark. and standard deviation Set the damage monitoring threshold to When the amplitude of the acoustic emission signal extracted in real time exceeds the damage monitoring threshold, the bottom servo system of the precision grinding machine tool automatically intervenes and executes a downgrade intervention program to reduce the actual grinding depth or the actual grinding speed.

[0014] Step 6: After a single grinding task is completed, perform a surface integrity test on the coated saw blade. The coated saw blades with localized coating damage will be transferred to the decoating and recoating process in a closed loop.

[0015] Furthermore, the critical grinding speed mentioned in step three is calculated using the following formula:

[0016]

[0017] In the formula, Critical grinding speed, in units of ; The tensile strength of the coating material, in units of ; The density of the matrix material, in units of ; The grinding speed influence coefficient is dimensionless and is determined by a combination of factors including the type of grinding wheel bond, abrasive grain size, coolant heat exchange capacity, and machine tool system rigidity. It can be measured through a standard orthogonal grinding temperature measurement experiment. For resin-bonded diamond grinding wheels and water-based coolant systems, the grinding speed influence coefficient... The value is between 0.02 and 0.05.

[0018] In practical applications, the grinding speed influence coefficient Calibration was achieved through the following orthogonal grinding temperature measurement experiment: using the actual grinding speed. and grinding depth For two factors, each should have at least three levels (e.g. Take 20 m / s, 30 m / s, and 40 m / s. Using diameters of 0.01 mm, 0.02 mm, and 0.03 mm, the highest temperature in the grinding arc zone was measured using an infrared thermal imager or the thermocouple embedding method. (Unit: °C). A linear regression model was established based on the measurement data. Among them, the regression coefficient The reciprocal of this is the grinding speed influence coefficient. ,Right now .

[0019] For users lacking experimental facilities, the following typical range can be selected based on the type of grinding wheel bond: resin-bonded grinding wheels. Metal-bonded grinding wheels Ceramic bonded grinding wheel .

[0020] Furthermore, the critical grinding depth mentioned in step three is calculated using the following formula:

[0021]

[0022] In the formula, Critical depth of grinding, in units of ; The critical stress coefficient of the coating material, in units of... ; The coating thickness is expressed in units of 1. ; The density of the matrix material, in units of ; This refers to the actual grinding speed, in units of... .

[0023] Furthermore, the critical stress coefficient of the coating material was determined by the following micro-indentation destructive test: a diamond square pyramid indenter was used to apply a normal load at a constant rate increasing on the surface of the coated sample to capture the critical load corresponding to the initiation of the first radial crack penetrating the interface, and the result was converted using the following formula:

[0024]

[0025] In the formula, The critical stress coefficient of the coating material, in units of... ; is the geometric constant of the diamond square pyramid indenter, which is dimensionless; Critical load, unit: ; The radial crack length measured from the center of the indentation, in units of .

[0026] Furthermore, the logic for setting the damage monitoring threshold in step five is as follows:

[0027] Acoustic emission signal data stream was acquired within 5 seconds after the start of grinding contact, and wavelet transform denoising and reconstruction processing were performed. The statistical average value of the root mean square value of the reconstructed signal was calculated. and standard deviation rigidly bind the damage monitoring threshold to ;

[0028] The machining parameter downgrade intervention procedure is as follows: the actual grinding depth is drastically reduced to 50% of the current set command value, or the actual grinding speed is reduced to 70% of the current set command value.

[0029] Furthermore, in step five, the wavelet transform denoising uses the Daubechies-4 wavelet as the mother wavelet function and performs a four-level orthogonal decomposition. After stripping the low-frequency coefficients, the coefficient flow of the high-frequency detail coefficients that maps the lattice fracture frequency band of the coating material is extracted for clean signal reconstruction.

[0030] Furthermore, in step five, in addition to the acoustic emission sensor, a high-frequency laser displacement sensor is mounted in parallel on the side of the grinding wheel frame of the precision grinding machine tool.

[0031] A laser displacement sensor densely collects surface height coordinates during the rotation cycle of a coated saw blade to construct a one-dimensional surface profile curve and calculates the dynamic evaluation value of surface roughness online.

[0032] The acoustic emission sensor signal and the laser displacement sensor signal are incorporated into the damage risk index fusion criterion equation:

[0033]

[0034] In the formula, This is a dimensionless damage risk index. The root mean square value of the reconstructed signal; This is the root mean square value corresponding to the damage monitoring threshold; This is a dynamic evaluation value for surface roughness; This is the preset maximum allowable online surface roughness value; and These are the weighting coefficients;

[0035] when When macroscopic peeling of the coating is detected, the servo system executes an emergency stop and retraction command for the spindle.

[0036] Furthermore, when the monitoring system identifies ,and and When the time derivatives are all greater than zero, the grinding arc region is determined to have entered a subcritical damage state; the servo system issues commands to reduce the actual grinding depth to 60% of the current set command value and the actual grinding speed to 80% of the current set command value.

[0037] Furthermore, the coolant circulation system described in step four is equipped with a plate heat exchanger; the cooling medium injected into the grinding wedge contact area is a water-based anti-rust grinding fluid, the jet flow rate is constrained to the range of 800 mL / min to 1200 mL / min, and the jet core temperature is maintained at 15℃ to 25℃.

[0038] Furthermore, the stripping and recoating process described in step six includes: constructing an electrolytic bath containing an anodic corrosion inhibitor to non-destructively peel off the failed old coating; after ultrasonic deep degreasing and ion bombardment cleaning of the substrate, the coated saw blade substrate is introduced into a physical vapor deposition (PVD) or chemical vapor deposition (CVD) device to chemically grow a hard coating again under the same physical parameter boundaries.

[0039] Furthermore, after determining the actual grinding speed and actual grinding depth in step three, the feed rate of the feed axis of the precision grinding machine tool is set to 0.005 mm / r to 0.02 mm / r.

[0040] Furthermore, a historical grinding energy accumulation factor is introduced to correct the nonlinear decay when calculating the critical grinding depth. The corrected critical grinding depth equation is as follows:

[0041]

[0042] In the formula, The corrected critical grinding depth, in units of ; The cumulative grinding energy input value is the integral of the spindle servo motor output power over time, after deducting the internal power consumption during machine tool idle operation. The unit is... ; This represents the maximum allowable energy input value for the coating material to prevent fatigue failure, expressed in units of... This value was determined through continuous grinding fatigue testing of the coated saw blade; when At that time, the control center executes Forced instructions.

[0043] Furthermore, when the control center calculates the corrected critical grinding depth... When the grinding depth drops below 20% of the initial critical depth of grinding calculated above, the grinding wheel dressing warning mechanism on the machine tool's human-machine interface is triggered; after completing the grinding wheel dressing operation, the system will accumulate the grinding energy input value. Reset to zero.

[0044] Furthermore, the isothermal high-pressure jet cooling of the grinding wedge contact area described in step four further includes a critical jet velocity feedforward control program based on the principle of fluid dynamics stagnation point pressure balance: The CNC system extracts physical environment parameters in real time and uses the following formula to feedforward and calculate the critical outlet velocity of the coolant jet:

[0045]

[0046] In the formula, To ensure the critical exit velocity for the coolant jet to penetrate the air boundary layer, the unit is... ; It is the empirical constant for boundary layer airflow repulsion, which is dimensionless and has a system preset range of 1.2 to 1.5; Set the actual grinding speed issued in step three, in units of ; Real-time air density at the ambient temperature during grinding operations, in units of ; The physical density of the working medium in the coolant circulation system, in units of... The main control logic obtains the critical exit speed. Then, it is used as the minimum constraint red line. Combined with the inherent throttling cross-sectional area boundary of the nozzle, the minimum fluid supply demand is deduced. The volumetric flow rate output of the constant pressure variable frequency pump is controlled in a closed loop, forcing the actual jet velocity to forcibly cross the minimum constraint red line, and establishing a forced convection heat transfer channel in the contact area that is not affected by air resistance.

[0047] Furthermore, in step five, after reconstructing the signal by extracting the high-frequency detail coefficients of the lattice fracture frequency band of the mapped coating, a stress wave spatial transmission distance attenuation adaptive compensation mechanism is embedded in parallel: The absolute position grating ruler feedback of the machine tool servo axis is read without delay via the underlying electrical drive bus, continuously establishing the Cartesian space topology between the current grinding contact centroid and the rigid mounting point of the acoustic emission sensor, rollingly calculating the transient spatial physical Euclidean distance between them, and substituting it into the following exponential compensation equation to extract non-destructive acoustic features:

[0048]

[0049] In the formula, The root mean square true value obtained after performing spatial transmission attenuation compensation; The root mean square initial state value is obtained by direct quantization of the original reconstructed signal; It is the base of the natural logarithm; The intrinsic elastic wave attenuation coefficient of the coated saw blade substrate material in the target ultrasonic monitoring frequency band is given by _____. ; The transient spatial physics Euclidean distance output by the spatial topology solution, in units of ; The static geometric reference distance from the initial grinding entry point of the cutting tooth to the acoustic emission sensor within the baseline self-learning window capture period, in units of The system uses the true root mean square value. The original root mean square initial state value is replaced and used as the absolute quantitative benchmark for calculating the underlying statistical average and standard deviation of the damage monitoring threshold for coated saw blades, as well as for triggering over-limit intervention.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] This invention extracts intrinsic parameters such as the tensile strength of the coating material, the density of the substrate material, and the critical stress coefficient of the coating. It then uses feedforward calculation to determine the critical grinding speed that does not induce thermal stress delamination at the coating interface and the critical grinding depth that does not induce microscopic mechanical fracture of the coating. The actual values ​​are then limited to a safety factor range. This simultaneously blocks both thermal delamination and mechanical fracture damage paths from their physical source, ending the uncontrolled situation of traditional processes relying on trial and error and having parameters in a blind box state. At the process monitoring level, this invention constructs a dynamic monitoring threshold based on wavelet transform reconstruction and statistical distribution of the acoustic emission signal from the initial stable cutting window. This method extracts the statistical average and standard deviation of the root mean square value of the reconstructed signal in real time, rigidly binding the damage judgment boundary to a statistical upper limit of "μ+3σ". This effectively distinguishes between normal processing background noise and transient stress waves caused by coating lattice fracture, completely eliminating erroneous interventions caused by Gaussian white noise such as cutting fluid impact and spindle vibration. This ensures the continuous and stable operation of the industrial field monitoring system, maintaining normal processing speed while ensuring zero coating damage.

[0052] By further introducing a multi-source heterogeneous information fusion perception architecture, and through the parallel deployment of acoustic emission sensors and high-frequency laser displacement sensors and the fusion criterion of damage risk index, the quantitative identification of subcritical damage state in the grinding arc zone and parameter adaptive degradation intervention are realized. This advances coating protection to the early stage of microcrack propagation, breaking through the limitation of traditional technology that only passively stops the machine after macroscopic peeling occurs.

[0053] This invention establishes a nonlinear decay model that dynamically shrinks the critical grinding depth as the tool's actual health condition by introducing a historical grinding energy accumulation factor. When the boundary enters the danger zone, it triggers a grinding wheel dressing warning and energy reset, forming a complete closed-loop defense architecture from physical boundary constraints of the machining process, multi-source online sensing intervention to equipment maintenance and coating recoating. This significantly improves the yield, process reliability, and overall equipment efficiency of coated saw blade grinding. Attached Figure Description

[0054] To more clearly illustrate the technical solutions of the embodiments of the present invention, 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 the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0055] Figure 1 This is a flowchart of the overall process of the method of the present invention.

[0056] Figure 2 The flowchart for constructing the dynamic damage monitoring threshold and intervention process for this invention is shown below.

[0057] Figure 3 This is a flowchart of the subcritical damage identification and intervention process of the present invention.

[0058] Figure 4 This is a flowchart illustrating the macroscopic damage emergency stop process triggered by the damage risk index fusion criterion of this invention.

[0059] Figure 5 This is a flowchart of the stripping and recoating process of the present invention. Detailed Implementation

[0060] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0061] The following is in conjunction with the appendix Figures 1-5 The embodiments of the present invention will be described in detail below.

[0062] Example 1: This example is for the combination of TiAlN (titanium aluminum nitride) hard coating and M2 high-speed steel substrate used in the cutting of medium and high carbon steel and alloy cast iron; the hardware platform relies on a five-axis linkage CNC precision grinding machine tool, the positioning accuracy of each linear axis is calibrated to 0.002 mm, the spindle adopts dynamic and static pressure bearings to suppress radial runout, and is equipped with a high flow rate water-based grinding fluid circulation system with an independent PID temperature control module.

[0063] The specific steps and methods are as follows:

[0064] Step 1: Physical and chemical deactivation treatment of the coated saw blade surface; During the initial machining or transfer process, hydrocarbons are physically adsorbed within the microscopic grain boundaries and pores of the coated saw blade surface, accompanied by localized oxidation caused by the high temperature of cutting. If these interface barriers are not removed, they will change the acoustic impedance characteristics of the coating surface, causing subsequent acoustic emission stress wave signals to attenuate at the gas-solid interface.

[0065] A 50 L deactivation treatment tank was constructed, and a 5% (w / w) weakly alkaline degreasing solution, mainly composed of sodium silicate and a nonionic surfactant, was injected. Coated saw blades were completely immersed in the solution using a specialized titanium alloy hanger. Ultrasonic transducers arranged in an array at the bottom of the tank were activated, with the operating frequency set to 40 kHz and the acoustic power density set to 0.5 W / cm². At this frequency, acoustic cavitation was induced within the solution: cavitation bubbles grown during the negative pressure half-cycle collapsed within microseconds during the positive pressure half-cycle, generating microjets with local pressures reaching hundreds of atmospheres. This purely physical microscopic impact force powerfully severed the van der Waals forces connecting large oil molecules to the coating surface, while simultaneously stripping away metal chips embedded in the coating's microcracks.

[0066] The ultrasonic treatment cycle lasts for 15 minutes. After removal from the tank, the coated saw blade is transferred to a three-stage deionized water rinsing tank to remove residual alkali. It is then thoroughly dried using a 70°C constant temperature hot air circulation system to expel trace amounts of water molecules adsorbed on the coating surface, ensuring the acoustic conductivity of the subsequent piezoelectric sensor coupling contact surface.

[0067] Step two: Dynamic radial runout detection and high-rigidity eccentricity correction of the spindle system; the deactivated coated saw blade is clamped onto the high-precision hydraulic expansion mandrel of the precision grinding machine spindle. The minute eccentric mass distribution is amplified by the spindle rotation, transforming it into nonlinear pulsations in the cutting thickness. Based on the kinematic cutting principle, the maximum undeformed chip thickness of a single abrasive grain is positively correlated with the spindle radial runout.

[0068] Lever-type dial indicators with a resolution of 0.001 mm are installed on the outermost circumferential end face and radial outer surface of the coated saw blade substrate. Manual rotation is used to perform a low-speed full-circumferential scan, recording the phase angles of the peaks and troughs. Based on the phase corresponding to the radial runout peak, a differential preload is applied to the locking bolts on the flange near that phase using a torque wrench. This preload induces a slight elastic deformation in the workpiece flange to compensate for the eccentricity. The stress is then released, and this process is repeated iteratively to forcibly correct the system's eccentricity. This correction process continues until the dial indicator pointer runout is constrained within a preset tolerance zone of 0.005 mm. This physical constraint eliminates the risk of local principal stress overload in the coating induced by sudden changes in thickness during transient cutting, from a geometrical perspective.

[0069] Step 3: First-principles safety boundary calculation based on macroscopic thermodynamics and microscopic fracture mechanics; the core of thermal delamination lies in the mismatch of thermal expansion coefficients between the coating and the substrate material under instantaneous high thermal gradients, resulting in extremely high interfacial shear stress. The tensile strength of this batch of TiAlN coatings was calibrated through standard tensile fatigue testing. 2500 MPa (i.e.) Pa), room temperature density of M2 high-speed steel matrix material It is 7850 kg / m³.

[0070] Grinding speed influence coefficient It is a dimensionless comprehensive parameter that integrates the thermodynamic properties of the contact area. Its value is jointly determined by the thermal conductivity of the diamond grinding wheel (D64 grit, resin binder), the convective heat transfer coefficient of the cutting fluid, and the stiffness of the machine tool spindle. Based on the standard empirical thermodynamic spectrum of metal cutting and combined with the conditions of this system, it is selected. .

[0071] The CNC unit of the precision grinding machine extracts the above parameters and calculates the critical grinding speed that does not cause thermal stress delamination at the coating interface. :

[0072]

[0073] As grinding wheel abrasive grains wear and dull over time, the proportion of work done by sliding friction increases during cutting, leading to a non-linear increase in heat generation. To preserve heat dissipation redundancy, the system sets 70% of this theoretical critical value as the upper limit for instruction execution, limiting the actual grinding speed... It is set to 17.8 m / s.

[0074] The physical thickness of the TiAlN coating on the coated saw blade was confirmed using a white light interferometer. for m. Solving for the critical grinding depth requires obtaining the critical stress coefficient of the coating material. This parameter was pre-extracted using a Vickers microindentation destructive experiment.

[0075] In an isolated laboratory at a constant temperature of 25±1℃, a servo loading system drove a diamond square pyramid indenter (face angle 136°) to press into the surface of the TiAlN coated sample at a constant micro-feed rate of 0.5 N / s, maintaining the load for 15 s. The interface morphology was monitored in real-time at high magnification using a scanning electron microscope, and the critical load corresponding to the initiation of the first radial main crack penetrating the interface was recorded. The measured value was 0.55 N, and the propagation length of the radial crack from the indentation center was also measured. for m. Combined with the geometric constants of the pressure head. Convert the intrinsic fracture toughness index of the coating, i.e., the critical stress coefficient. :

[0076]

[0077] in, Substituting into

[0078]

[0079] The above physical parameters and A mechanical damage boundary model derived from indentation fracture mechanics was used to calculate the critical grinding depth. :

[0080]

[0081] The machine tool's main control system takes 40% of the calculated result as the actual grinding depth and issues a command, i.e., 0.011 mm, to counteract disturbances caused by the machining system's elastic tool deflection and the microscopic unevenness of the grinding wheel profile. The machine tool's feed rate is set to 0.01 mm / r.

[0082] Step 4: Fluid dynamics and thermodynamic temperature control of the grinding contact area; the machining cycle command is started, the spindle accelerates to the set speed, and the feed axis approaches the workpiece.

[0083] The closed-loop controlled coolant circulation system is started first: the water-based rust-preventive grinding fluid undergoes heat exchange via a plate heat exchanger, stabilizing the jet core temperature at 20℃ (control accuracy ±1℃). The coolant is ejected through a tapered wide-mouth nozzle with a flow-guiding structure, and the jet flow rate is constrained to 1000 mL / min by a constant-pressure variable-frequency pump. The high-pressure fluid cuts into the wedge-shaped slit area formed by the contact between the grinding wheel and the coated saw blade. At the cutting linear velocity, a high-speed airflow boundary layer forms on the surface of the grinding wheel; if the jet pressure and flow rate are insufficient to penetrate this air resistance layer, the coolant will be blocked and unable to enter the cutting arc area. In this embodiment, the high-pressure jet penetrates the air resistance layer, forcing convection heat transfer to rapidly deprive the Joule heat converted from the work done by the abrasive grains' micro-cutting deformation resistance, suppressing the occurrence of local film boiling in the contact area.

[0084] Step 5: Broadband acoustic response statistical monitoring and sub-second intervention network construction; A broadband piezoelectric acoustic emission sensor is attached to the high-rigidity tailstock of a precision grinding machine using a high-conductivity acoustic coupling agent. This sensor, with a resonant frequency of 200 kHz and a sensitivity exceeding 60 dB, is used to capture transient high-frequency elastic stress waves released due to lattice bond breakage. The signal is amplified by a low-noise preamplifier (40 dB gain) and then input to a high-speed data acquisition card with a sampling rate of 250 kHz.

[0085] The first 5 seconds of material removal during the contact between the grinding wheel and the saw blade are defined by the system as the baseline self-learning window. Within this window, the microstructure of the grinding wheel is in a reconstructed state, and the cutting force output is stable. The data acquisition card acquires the raw acoustic emission signal stream within these 5 seconds, and the wavelet transform noise reduction module is invoked in the DSP digital signal processor.

[0086] The module selects the Daubechies-4 (db4) wavelet as the mother wavelet function and performs a four-level orthogonal decomposition on the original signal. The low-frequency band (0-100 kHz) is interspersed with mechanical vibration noise from the spindle rotation, electromagnetic hum from the servo motor, and hydrodynamic noise from coolant impact. The algorithm truncates and discards the low-frequency approximation coefficients, extracting only the high-frequency detail coefficients corresponding to the characteristic frequency band of microfracture at the grain boundaries of the TiAlN coating (150 kHz-200 kHz). These high-frequency detail coefficients are then used to reconstruct the signal, obtaining a clean acoustic signal sequence.

[0087] The algorithm continuously calculates the statistical average of the root mean square value of the reconstructed signal over a 5-second period. and standard deviation The dynamic damage monitoring threshold is locked at [value]. On the horizontal line. This dynamic statistical benchmark replaces the traditional empirical fixed threshold.

[0088] At the 18-minute mark of the machining process, abnormal micro-fracture occurred in a localized area of ​​individual abrasive grains on the grinding wheel, resulting in a negative rake angle and an exponential jump in localized micro-cutting resistance. Transient stress waves were released from deep within the coating microstructure, and the amplitude of the reconstructed signal captured by the acoustic emission sensor broke down within approximately 2 ms. Statistical upper limit.

[0089] In a sub-second instant, the CNC underlying logic takes over the servo drive, invokes the machining parameter degradation intervention program, and issues an emergency command: the actual grinding depth of the feed axis drops sharply from 0.011 mm to 0.0055 mm (50% of the current command value). The normal cutting load is abruptly unloaded as the cutting depth is halved, the stress concentration at the microcrack tips at the coating grain boundaries is relieved, and the high-frequency acoustic emission energy collapses back into the safe threshold zone within 1.5 seconds.

[0090] Step six: Surface integrity assessment and closed-loop reset based on materials chemistry; after the entire batch of grinding tasks is completed, the coated saw blade is transferred to a high-precision visual measurement laboratory at a constant temperature of 20℃. After extracting macroscopic morphology data using a coordinate measuring machine, the coating near the cutting edge is scanned tooth by tooth using a stereomicroscope with a magnification of 1000x.

[0091] For coated saw blades with localized minor network-like microcracks, a traceability QR code was laser-marked onto the non-working area of ​​the substrate, and the blade was then transferred to a professional stripping and recoating process. An alkaline electrolyte system containing an organic amine anodic corrosion inhibitor was used, with the coated saw blade acting as the anode connected to a DC power supply, and the current density controlled at 0.2 A / cm². Through a redox reaction, the transition metal phase in the TiAlN coating was dissolved at specific points, while the organic amine corrosion inhibitor formed a dense adsorption protective film on the M2 high-speed steel substrate surface, achieving non-destructive removal of the old coating.

[0092] After the coating is removed, the substrate undergoes low-pressure micro-blasting with 200-mesh high-purity white corundum abrasive to activate surface grain boundaries and increase the microscopic specific surface area. It is then subjected to ultrasonic degreasing and vacuum ion bombardment cleaning. The purified substrate is then placed in an ultra-high vacuum physical vapor deposition reaction chamber, where a vacuum is drawn to... Pa, high-purity nitrogen gas is introduced to stabilize the working pressure at [pressure value]. Pa, with the substrate bias voltage set to -100 V. Using multi-arc ion plating technology, titanium and aluminum ions on the target material evaporate and ionize under the action of a high-energy electric arc, reacting and depositing with nitrogen ions on the substrate surface to re-epitaxically grow a dense TiAlN coating with a nanotwin structure.

[0093] Example 2: Based on Example 1, this example constructs a multi-source signal fusion evaluation system and a nonlinear dynamic boundary constraint algorithm based on historical grinding work for AlCrN (aluminum chromium nitrogen) strip-coated saw blades used for cutting high-temperature heat-resistant alloys (such as Inconel 718) for aero-engines.

[0094] Specifically as follows:

[0095] AlCrN coatings possess a dense amorphous alumina protective film and high-temperature red hardness due to their high aluminum content. However, due to the change in lattice constant, the brittle phase characteristics change accordingly, making them more sensitive to alternating stress fields and thermal accumulation.

[0096] Tests revealed that the tensile strength of this batch of AlCrN coatings was [data missing]. 3200 MPa Pa), density of matrix material The value is 7850 kg / m³. Grinding speed influence coefficient. The critical grinding speed is calibrated to 0.05 based on the condition of the grinding wheel and coolant system. The calculation is as follows:

[0097]

[0098] Take 70% of this value as the actual grinding speed, that is Rounded down, it is 22 m / s.

[0099] Coating physical thickness Calibrated as m. Micro-indentation destructive testing was performed using a diamond square pyramid indenter to determine the critical load. N, radial crack length m. Indenter geometric constant The critical stress coefficient was calculated as follows:

[0100]

[0101] Then, the theoretical initial value of the critical grinding depth under the undamped state is obtained:

[0102]

[0103] The system takes 50% of this value, i.e., 0.0075 mm, as the initial actual grinding depth.

[0104] Mechanical failure of the coating does not only occur due to transient brittle fracture under a single massive impact load, but also stems from dislocation pile-up and energy dissipation under the combined action of long-term alternating cutting stress and heat flow pulses in the grinding contact area. A high-frequency Hall current sensor and a high-precision voltage transformer are connected in parallel in the spindle drive motor circuit of the system electrical bus. The DSP processing unit synchronously acquires the three-phase transient active power of the spindle with an discrete step size of 1 ms. After deducting the internal power loss during machine tool idle operation, the effective cutting output power is numerically integrated along the time axis to calculate the cumulative grinding energy input value in real time. .

[0105] Five AlCrN coated saw blades from the same batch were subjected to continuous grinding fatigue failure tests under standard safe grinding parameters. The cumulative energy value of each blade was recorded when the first microcrack appeared in the coating, using a microscope. The maximum allowable energy input value was determined by taking 80% of the average failure energy value of the five tests. This batch is calibrated as J.

[0106] The system's underlying mechanism calls the boundary dynamic correction equation to perform a nonlinear decay calculation on the upper limit of the critical grinding depth:

[0107]

[0108] When the grinding task reached the 42-minute mark, the power integrator displayed the cumulative grinding energy input value. Da J, revised allowable grinding depth The temperature dropped to 20% of the initial calculated critical value. The system determined that the current saw blade coating tolerance was approaching the red line range, and the grinding wheel geometry had become dull, resulting in a surge in heat generation. The CNC system triggered the grinding wheel dressing early warning mechanism in the human-machine interface, paused the feed program, and activated the built-in diamond dressing roller to perform a full-surface reconstruction and sharpening of the grinding wheel. After the dressing operation was completed, the accumulated grinding energy input value was recorded. Forced zeroing, dynamic boundary Release back to the initial maximum value.

[0109] In the grinding of aerospace-grade, difficult-to-machine materials, single physical quantity sensors may experience blind spots due to complex working conditions (cutting fluid splashing, machine tool electrical harmonic interference).

[0110] In this embodiment, based on the acoustic emission sensor, a non-contact high-frequency laser displacement sensor is mounted in parallel on the side of the high-rigidity grinding wheel frame of the precision grinding machine tool to construct a dual monitoring and defense line of stress wave and macroscopic morphology.

[0111] The laser displacement sensor operates at a wavelength of 650 nm, with a projected spot diameter constrained to 30 μm, a sampling frequency of 10 kHz, and a Z-axis optical resolution of 0.1 μm. The sensor probe is mounted within a stainless steel labyrinthine air curtain protective enclosure with multiple convoluted channels. Dry, clean compressed air at a pressure of 0.4 MPa is continuously supplied to the enclosure, creating a high-pressure, high-speed air curtain within the labyrinthine channels. This airflow actively isolates the high-pressure coolant splashing from the grinding zone, ensuring that the optical lenses and laser path remain undisturbed. The laser beam is projected onto the freshly coated saw blade surface, perpendicular to the normal orientation of the measured surface, just after it has left the grinding wedge contact zone.

[0112] As the coated saw blade rotates periodically, the laser displacement sensor densely collects surface height coordinate data, constructing a one-dimensional discrete point cloud of surface contour data in the memory of the industrial control computer.

[0113] The raw contour data contains a large number of low-frequency fluctuations representing macroscopic shape errors (spindle rotation error, workpiece clamping residual eccentricity, and machine tool low-frequency vibration). Directly calculating roughness will result in baseline drift error. The IPC underlying layer uses an autoregressive moving average model for online filtering, with the autoregressive order... Moving average order The low-frequency trend term of the current contour signal is fitted in real time using the least squares method and then stripped. After high-pass filtering and purification, a one-dimensional surface contour curve reflecting only the micro-cutting texture is obtained. On this baseline, the dynamic evaluation value of surface roughness is calculated in real time with a 50 ms sliding window. .

[0114] At the fusion decision-making level of the control center, the acoustic emission sensor reconstructs the amplitude. Solved with laser sensor Synchronously incorporate the damage risk index fusion criterion equation:

[0115]

[0116] Weighting coefficient and All were assigned the value 0.5. Extracted during the initial no-damage period Statistical upper limit, The constraint is 0.8 μm.

[0117] At the 27th minute of the machining process, a trace amount of free air entered the machine tool's centralized fluid supply system piping network, causing a transient pressure drop in the jet at the tapered wide-mouth nozzle lasting 0.5 seconds, resulting in the grinding contact area entering a boundary lubrication state. The acoustic emission sensor captured the reconstructed signal amplitude. A sharp increase to the threshold 92% of the data did not trigger the single threshold alarm limit. Slight plastic rheology and deepening of micro-grooves occurred on the coating surface, which was calculated by the laser sensor. It deteriorated to 0.65μm. This was calculated by the fusion module. , fall Subcritical damage range. The algorithm calculates the time derivative of the underlying physical quantities over ten discrete sampling periods, and the results show... and This confirms that the risk of damage is in a continuously diverging upward trend.

[0118] The control center issues a dynamic degradation command via the underlying fieldbus: the actual grinding depth is forcibly reduced to 60% of the original command value (0.0045 mm), and the spindle speed is simultaneously reduced to 80% of the original command value. The machining heat flux density and contact normal force are mitigated within 0.2 seconds. It has fallen back to the safety baseline of 0.43.

[0119] Example 3: This example addresses the engineering bottleneck posed by the high hardware cost and sensitivity to parasitic electromagnetic radiation from high-power equipment in workshops for piezoelectric acoustic emission sensors used in woodworking or general aluminum alloy profile cutting with coated saw blades. This example provides a variant of the monitoring method with hardware reduction.

[0120] A triaxial MEMS (Micro-Electro-Mechanical System) accelerometer / vibration sensor replaces the wideband piezoelectric emission sensor, and is rigidly mounted on the front bearing housing of the precision grinding machine spindle using a powerful permanent magnet. The signal sampling frequency is adjusted to 20 kHz, effectively monitoring a bandwidth covering the mechanical vibration frequency band from 10 kHz to 50 kHz.

[0121] To compensate for the sensitivity disadvantage of low-frequency vibration sensors in responding to weak microscopic grain boundary fracture signals, frequency domain calibration experiments were conducted before the equipment was put into formal production.

[0122] For this specific model of machine tool and fixture system, three coated saw blade samples from the same batch were extracted. The grinding parameters were increased until macroscopic damage to the coating occurred. Simultaneously, the acoustic emission signal sequence at the moment of fracture of the standard sample was recorded using an external high-frequency acquisition card. With vibration acceleration signal sequence Two discrete-time series were transformed to the frequency domain, and cross-correlation spectral density calculations were performed. By searching for the peak envelope group on the amplitude-frequency response curve, the resonant characteristic frequency band excited by the transient stress wave from coating peeling in the machine tool spindle-fixture-workpiece system structure was located. Test calibration showed that the energy of this characteristic vibration is concentrated within a narrow resonant envelope of 22 kHz to 28 kHz. This characteristic frequency band is repeatable for the same model of machine tool system.

[0123] When entering the batch grinding stage, the DSP chip calls the Butterworth bandpass digital filter with a lower cutoff frequency of 22kHz and an upper cutoff frequency of 28kHz.

[0124] After the original vibration signal passes through the filter, low-frequency vibration interference such as cutting fluid impact, motor rotor imbalance, and guide rail friction is eliminated. The algorithm extracts the root mean square (RMS) acceleration index of the filtered signal in real time, and constructs a statistical distribution baseline by extracting the RMS index within the first 5 seconds of grinding contact. When transient high cutting forces are caused by abrasive grain breakage or poor chip removal during grinding, the root mean square acceleration index in the resonant frequency band breaks through the statistical baseline, and the servo system intervenes by combining speed reduction and tool retraction.

[0125] After processing, for saw blades with coatings showing localized microscopic damage, a closed-loop chemical vapor deposition (CVD) recoating process is initiated. An acidic removal solution system containing hydrogen peroxide and tartaric acid is used to chemically dissolve the damaged old coating at a constant temperature of 50°C.

[0126] After cleaning and drying, the substrate is placed on a graphite boat in a CVD high-temperature reactor at 1000℃. The vacuum level is then evacuated to... After Pa, titanium tetrachloride vapor, methane gas, and high-purity hydrogen gas as a reducing agent are precisely proportioned and introduced into the furnace cavity. Driven by a high temperature of 1000℃, a gas-solid phase chemical deposition reaction occurs in the furnace. Titanium carbide molecules nucleate at the microscopic grain boundaries of the matrix and continue to grow along the epitaxial direction, forming a new wear-resistant coating that is metallurgically bonded to the matrix. The byproduct hydrogen chloride gas is continuously extracted by a vacuum pump and neutralized by an alkali tower.

[0127] Comparative Example 1: Comparative Example 1 (50 pieces) simulates the typical empirical machining mode currently used in tool maintenance factories.

[0128] Operators do not input the coating tensile strength With critical stress coefficient Feedforward calculations were performed, and the grinding wheel speed was set to 30 m / s directly on the CNC system interface based on experience, with the actual grinding depth set to 0.03 mm. This machine tool was not equipped with acoustic emission or any form of online monitoring and early warning hardware.

[0129] Processing operation records and microscopic metallographic analysis show that:

[0130] The grinding speed of 30 m / s exceeds the critical grinding speed calculated by solving the thermodynamic equation in Example 1. (25.39 m / s) The Joule heat injection rate generated by the abrasive grains sliding on the workpiece surface exceeds the thermal conductivity limit of the saw blade substrate material and the convection dissipation capacity of the water-based coolant. The temperature at the center of the cutting arc zone spikes, and the coolant vaporizes in the contact area, forming a film boiling phenomenon. The surface temperature of the TiAlN coating exceeds the red hardness limit of oxidation (approximately 800℃), resulting in thermally induced blue change. The release of thermal stress at the interface between the coating and the substrate leads to delamination and bulging. The 0.03 mm feed depth exceeds the mechanical limit constrained by fracture toughness. (0.028 mm), the normal component force applied when a single diamond abrasive grain cuts into the coating crushes the brittle phase network.

[0131] Of the 50 saw blades in the batch, 18 showed macroscopic blocky peeling of the coating on the cutting edge and back face, along with radial crack networks extending deep into the substrate. The overall reject rate for the first inspection was 36%. Saw blades with substrate tearing damage lost the physical basis for repair and recoating.

[0132] Comparative Example 2: Comparative Example 2 group (50 pieces) retains the online acoustic emission monitoring hardware module, but does not use the safety grinding parameters calculated by the feedforward method of this invention, and also abandons the self-learning method based on the initial stage of cutting. Dynamic statistical threshold. Operators, following the factory default macro settings of the foreign sensor supplier, lock the alarm trigger threshold at an absolute voltage amplitude of 1.5 V in the system monitoring backend.

[0133] During actual workshop trial cutting operations, the precision grinding machine tool experienced periodic pulsating start-stop of the centralized hydraulic pump and broadband noise generated by the high-pressure water-based coolant impacting the titanium alloy fixture flange at a flow rate of 1000 mL / min. The acoustic amplitude of this noise exhibited multiple transient spikes throughout the cutting cycle, frequently breaking through the 1.5 V absolute voltage threshold. These Gaussian white noise characteristic spikes were logically interpreted as coating fracture damage, forcibly triggering 47 false alarms, emergency shutdowns, and spindle retraction actions under normal cutting contact conditions.

[0134] Frequent sudden stops and secondary feed contacts subject the cutting edge to alternating impact loads during the cut-out and cut-in moments, inducing microscopic chipping and fatigue damage to all three saw blades. Statistics show that although the scrap rate decreased to 6% (3 blades) after the introduction of a monitoring system, the overall equipment efficiency (OEE) of the machine tool was less than 20%, and the processing cycle time for a single saw blade increased fourfold, making it impossible to establish a stable and continuous industrial production line cycle on the processing site.

[0135] In contrast, the 50 coated saw blades processed using the control logic of Embodiment 1 of this invention achieved an overall batch yield of 100%, with a processing cycle time comparable to the standard process.

[0136] Example 4: This example addresses large-scale tool arrays with massive machining spans or extremely wide radii of rotation (e.g., TiCN-coated saw blades for heavy-duty metal cold saws with an outer diameter of 800 mm). The physical span between the cutting arc zone and the fixed-point monitoring sensor undergoes drastic nonlinear drift within a single task cycle, and the difficulty of stripping boundary gas layers from large-diameter grinding wheels under high linear velocity limits increases exponentially. This example constructs a dual-layer physical barrier of hydrodynamic feedforward penetration and adaptive spatial compensation of the monitoring signal, establishing a robust machining mechanism under polarized conditions based on the underlying logic of solid-state acoustic transmission attenuation limits and fluid stagnation momentum conservation.

[0137] During the preparation stage of precision grinding, the system's meteorological module extracts the real-time air density in the workshop as 1.22 kg / m³, and the density of the fully synthetic water-based anti-rust grinding fluid in the centralized fluid supply network is calibrated to 1040 kg / m³. The CNC system calculates and issues an actual grinding speed of 25 m / s based on the thermodynamic model of this invention.

[0138] In order to completely tear apart the dense air boundary layer surrounding the outer circumference of the high-speed grinding wheel, the main control core retrieved the critical jet velocity intervention control program and set the empirical constant for resisting centrifugal airflow at the conservative upper limit of 1.5.

[0139] Through precise calculation using the fluid pressure balance equation, the minimum critical outlet velocity of the coolant jet was locked at 1.28 m / s. The fluid distribution unit read that the actual effective throttling cross-sectional area of ​​the tapered wide-mouth nozzle was 20 mm². Based on this, it deduced in reverse and rigidly increased the steady-state flow command of the variable frequency constant pressure pump to 2000 mL / min in the underlying feedforward control loop. This flow load forced the nozzle terminal to eject a 1.67 m / s ultra-high velocity liquid column with an overwhelming stagnation momentum advantage. This miniature high-pressure liquid column precisely cut through the aerodynamic barrier like a solid cold front, forcibly injecting liquid phase cooling into the wedge-shaped cutting slit region, thus nipping the nonlinear thermal accumulation and lattice thermal degradation that are easily induced by dry friction on a large contact surface at the source of fluid dynamics.

[0140] A dynamic adaptive compensation network defense architecture for stress wave spatial transmission distance attenuation is activated in parallel. When a large TiCN-coated saw blade is subjected to sequential tooth surface grinding on the rotary indexing axis of a precision grinding machine, the physical distance between the acoustic emission sensor magnetically attached to the outer wall of the spindle stator casing and the transient breakage point of the cutting continuously increases and decreases with the rotation angle.

[0141] In the laboratory, preliminary laser-ultrasonic interferometry tests have precisely anchored the intrinsic elastic wave attenuation coefficient of the SKS51 alloy matrix to 3.5 m⁻¹ in the 150 kHz core monitoring frequency band. The machine tool electrical drive bus captures the three-dimensional coordinate data stream of the interpolation grating ruler in parallel with extremely fine granularity of 1 millisecond, and calculates the transient spatial physical Euclidean distance from the geometric centroid of the contact micro-area to the sensor at high frequency.

[0142] After the cutting process begins, the initial static geometric reference distance during the first tooth grinding self-learning window is fixed at 0.15 m by the system's underlying register. When the servo indexing table rotates the machining cutting point to the farthest diagonal tooth position away from the machine tool spindle, the transient spatial physical Euclidean distance has drastically increased to 0.85 m. The underlying compensation algorithm substitutes the real-time coordinate deviation into the exponential decay compensation equation and uses the amplification constraint factor that dynamically increases with distance to perform time-delay adaptive gain compensation on the initial state value of the reconstructed signal after wavelet transform denoising and background noise removal.

[0143] Verification data characterization, and the true root mean square value generated after back-correction by the acoustic model, eliminates the peak passivation phenomenon caused by distance attenuation, constructing a spatially consistent global defense threshold. In a batch of 60 heavy-duty coated saw blades for regrinding and mass production, this spatial compensation architecture successfully captured two latent precursors of microscopic cleavage fracture of the matrix carbides at the extreme distance of the far-end blind zone, instantly linking the machine tool's bottom-level servo cutting feed, successfully intercepting all false negatives throughout the batch, and achieving a 42% solid gain in the average comprehensive cutting fatigue life of the saw blades against the trend.

[0144] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0145] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A precision grinding damage-free machining method of a coated saw blade, characterized by, Includes the following steps: Step 1: Perform physical and chemical pretreatment on the coated saw blade to remove mechanical impurities and chemical oxide layers adhering to the surface of the coated saw blade; Step 2: Install the pre-treated coated saw blade onto the spindle of a precision grinding machine and perform dynamic radial runout detection and eccentricity correction to constrain the radial runout value of the coated saw blade within the preset tolerance range. Step 3: Extract the tensile strength of the coating material and the density of the matrix material of the coated saw blade. Combine this with the grinding speed influence coefficient to calculate the critical grinding speed that will not cause thermal stress delamination at the coating interface. Set the actual grinding speed to within 60% to 80% of this critical grinding speed. Extract the critical stress coefficient of the coating material, coating thickness, and matrix material density of the coated saw blade. Combine this with the actual grinding speed to calculate the critical grinding depth that will not cause micro-mechanical fracture of the coating. Set the actual grinding depth to within 30% to 50% of this critical grinding depth. Step 4: During the precision grinding cycle, start the coolant circulation system to perform constant temperature high-pressure jet cooling on the grinding wedge contact area; Step five, deploy acoustic emission sensors to acquire the elastic stress wave state of the grinding arc area in real time; within the initial stable cutting window where no coating damage occurs, perform wavelet transform noise reduction on the acquired acoustic emission signals, extract the high-frequency detail coefficients mapping the coating lattice fracture frequency band to perform signal reconstruction, take the root mean square value of the reconstructed signal as the quantitative benchmark of the acoustic emission signal amplitude, and calculate the statistical average value of the benchmark and standard deviation Set the damage monitoring threshold to ; when the real-time extracted acoustic emission signal amplitude exceeds the damage monitoring threshold, the precision grinding machine tool bottom layer servo system automatically intervenes, and executes the processing parameter degradation intervention program of reducing the actual grinding depth or reducing the actual grinding speed; Step 6: After a single grinding task is completed, perform a surface integrity test on the coated saw blade. The coated saw blade with localized coating damage is then transferred to the closed loop of the decoating and recoating process.

2. A precision grinding damage-free machining method of coated saw blade according to claim 1, characterized in that, The critical grinding speed mentioned in step three is calculated using the following formula: wherein Vc is the critical grinding speed, unit is m / s ; σc is the tensile strength of the coating material, unit is MPa ; ρc is the density of the coating material, unit is g / cm3 ; is the grinding speed influence coefficient, dimensionless, which is determined by the bond type of the grinding wheel, the size of the abrasive particles, the heat exchange capacity of the cooling liquid and the rigidity of the machine tool system, and can be determined by standard orthogonal grinding temperature measurement experiment For resin-bonded diamond grinding wheels and water-based coolant systems, the grinding speed influence coefficient is... The value is between 0.02 and 0.

05.

3. The precision grinding and damage prevention method for coated saw blades according to claim 1, characterized in that, The critical grinding depth mentioned in step three is calculated using the following formula: In the formula, Critical depth of grinding, in units of ; The critical stress coefficient of the coating material, in units of... ; The coating thickness is expressed in units of 1. ; The density of the matrix material, in units of ; This refers to the actual grinding speed, in units of... .

4. The precision grinding and damage prevention method for coated saw blades according to claim 3, characterized in that, The critical stress coefficient of the coating material was determined by the following micro-indentation destructive test: a diamond square pyramid indenter was used to apply a normal load at a constant rate increasing on the surface of the coated sample to capture the critical load corresponding to the initiation of the first radial crack penetrating the interface, and the load was converted according to the following formula: In the formula, The critical stress coefficient of the coating material, in units of... ; is the geometric constant of the diamond square pyramid indenter, which is dimensionless; Critical load, unit: ; The radial crack length measured from the center of the indentation, in units of .

5. The precision grinding and damage prevention method for coated saw blades according to claim 1, characterized in that, The logic for setting the damage monitoring threshold in step five is as follows: Acoustic emission signal data stream was acquired within 5 seconds after the start of grinding contact, and wavelet transform denoising and reconstruction processing were performed. The statistical average value of the root mean square value of the reconstructed signal was calculated. and standard deviation rigidly bind the damage monitoring threshold to ; The machining parameter downgrade intervention procedure is as follows: the actual grinding depth is drastically reduced to 50% of the current set command value, or the actual grinding speed is reduced to 70% of the current set command value.

6. The precision grinding and damage prevention method for coated saw blades according to claim 1, characterized in that, In step five, wavelet transform denoising uses the Daubechies-4 wavelet as the mother wavelet function and performs four-level orthogonal decomposition. After stripping the low-frequency coefficients, the coefficient flow of the high-frequency detail coefficients that maps the lattice fracture frequency band of the coating material is extracted for clean signal reconstruction.

7. The precision grinding and damage prevention method for coated saw blades according to claim 1, characterized in that, In step five, a high-frequency laser displacement sensor is mounted in parallel on the side of the grinding wheel head of the precision grinding machine, in addition to the acoustic emission sensor. A laser displacement sensor densely collects surface height coordinates during the rotation cycle of a coated saw blade to construct a one-dimensional surface profile curve and calculates the dynamic evaluation value of surface roughness online. The acoustic emission sensor signal and the laser displacement sensor signal are incorporated into the damage risk index fusion criterion equation: In the formula, This is a dimensionless damage risk index. The root mean square value of the reconstructed signal; This is the root mean square value corresponding to the damage monitoring threshold; This is a dynamic evaluation value for surface roughness; This is the preset maximum allowable online surface roughness value; and These are the weighting coefficients; when When macroscopic peeling of the coating is detected, the servo system executes an emergency stop and retraction command for the spindle.

8. The precision grinding and damage prevention method for coated saw blades according to claim 7, characterized in that, When the monitoring system identifies ,and and When the time derivatives are all greater than zero, the grinding arc region is determined to have entered a subcritical damage state; the servo system issues commands to reduce the actual grinding depth to 60% of the current set command value and the actual grinding speed to 80% of the current set command value.

9. A precision grinding and damage-preventing machining method for coated saw blades according to claim 1, characterized in that, The coolant circulation system described in step four is equipped with a plate heat exchanger; the cooling medium injected into the grinding wedge contact area is a water-based rust-preventive grinding fluid, the jet flow rate is constrained to the range of 800 mL / min to 1200 mL / min, and the jet core temperature is maintained at 15℃ to 25℃.

10. A method for precision grinding and damage prevention of coated saw blades according to claim 1, characterized in that, The stripping and recoating process described in step six includes: constructing an electrolytic bath containing an anodic corrosion inhibitor to non-destructively peel off the failed old coating; after ultrasonic deep degreasing and ion bombardment cleaning of the substrate, the coated saw blade substrate is introduced into a physical vapor deposition (PVD) or chemical vapor deposition (CVD) device to chemically grow a hard coating again under the same physical parameter boundaries.

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