A grinding method for TCT solid-head carbide cutting tools with high aspect ratio

Abstract

This invention relates to the field of precision manufacturing and machining technology for metal cutting tools, and discloses a grinding method for large aspect ratio TCT integral head carbide tools. The method involves clamping the tail shank of the carbide tool to be machined, and establishing a non-contact radial support boundary and an axial buffer boundary for the overhanging section; cooling, lubricating, and chip removal of the grinding contact area using a cooling and lubricating medium; generating zoned linkage grinding control data based on the local bending support state; generating feed correction and workpiece spindle speed correction based on grinding process status data; and updating the process boundaries after machining based on dimensional deviation data, surface morphology data, and grinding process data. This method is used to reduce tool deflection, thermal expansion and contraction, and chatter errors in the grinding of slender carbide tools.

Description

Technical Field

[0001] This invention relates to the field of precision manufacturing and machining technology for metal cutting tools, specifically to a grinding method for a large aspect ratio TCT integral head carbide tool. Background Technology

[0002] Large length-to-diameter ratio TCT solid-head carbide cutting tools are commonly used for cutting deep cavities, narrow grooves, micro-holes, complex curved surfaces, and difficult-to-machine materials. During the grinding process, these carbide tools are typically held by a tail shank, with the head or working section extending a long distance towards the diamond wheel. Carbide materials possess high hardness and wear resistance, but also exhibit high brittleness, susceptibility to hot cracking, and the difficulty in completely eliminating localized surface damage through subsequent processes. For carbide tools with small outer diameters and large overhangs, the grinding normal force generated when the diamond wheel cuts into the outer diameter or groove area of ​​the tool causes the overhanging section to deviate from the theoretical centerline. This deviation results in an actual depth of cut less than the programmed depth of cut, leading to deviations in groove depth, cutting edge width, core thickness, outer diameter, and the axial profile of the carbide tool.

[0003] When machining long drills, long milling cutters, or slender rod-shaped workpieces, existing CNC tool grinders typically use mechanical stabilizers, V-blocks, roller guide sleeves, or center rests as auxiliary supports. While these auxiliary supports can improve the radial constraint of the overhanging machining section to some extent, there is direct contact between the support structure and the outer diameter of the carbide tool. Fine grinding debris, coolant residue, diamond wheel shedding particles, and localized thermal expansion generated during grinding alter the actual pressure distribution at the contact interface, turning the support surface, originally intended for positioning, into a source of scratches or frictional heat. For TCT integral head carbide tools, the outer diameter surface, cutting edge surface, or guide surface can affect the cutting stability of the finished carbide tool. Fine scratches, indentations, or heat-induced discoloration zones introduced by contact supports reduce the consistency of the finished carbide tool.

[0004] To reduce grinding temperature, current processes often increase the injection pressure and flow rate of water-based or oil-based grinding fluids. High-flow-rate coolant can remove some grinding heat and debris, but for small-diameter, long-overhanging carbide cutting tools, the high-speed fluid flow applies a lateral fluid load to the overhanging section. This lateral fluid load, combined with the normal force of the diamond wheel grinding, easily increases low-frequency bending vibration. Cryogenic cooling media and micro-lubrication are also used to reduce grinding heat, but if the injection direction and flow rate of the cryogenic medium are not coordinated with the debris discharge state, the support state of the carbide cutting tool, and the diamond wheel's entry position, secondary debris compression, cryogenic impact, or insufficient cooling may occur in localized areas. Simply reducing the grinding temperature cannot automatically solve the tool deflection problem in the overhanging section.

[0005] In existing grinding control systems, grinding normal force, diamond wheel spindle power, or post-machining dimensional inspection results are often used as the basis for feed correction. For workpieces with high rigidity, feedback control based on grinding normal force can improve machining stability. For large aspect ratio TCT solid-head carbide tools, error sources include bending deflection in the overhang machining section, local thermal expansion and contraction of the carbide tool being machined, micro-displacement of the tail shank clamping boundary, diamond wheel profile wear, and workpiece spindle chatter. Different error sources are superimposed in time and space, and a single grinding normal force signal cannot directly distinguish between bending error and thermal error. If an increase in grinding normal force is directly interpreted as excessive feed depth, the control system may incorrectly reduce the feed; if the post-machining dimensional deviation is directly used for the next equal-amount compensation, it is difficult to suppress dynamic chatter and local thermal drift in the current single-piece machining. Summary of the Invention

[0006] The purpose of this invention is to provide a grinding method for TCT integral head carbide tools with large length-to-diameter ratio. The technical problem to be solved by this invention is that during the grinding process of TCT integral head carbide tools with large length-to-diameter ratio, contact-type guide supports are prone to introducing surface scratches and frictional heat. Single cooling cannot constrain the force displacement of the overhanging machining section. Single grinding normal force feedback is difficult to distinguish between bending deflection error and thermal expansion and contraction error, resulting in instability of groove size, outer circle size and surface morphology along the axis of the carbide tool to be machined.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A grinding method for a high aspect ratio TCT solid-head carbide cutting tool includes: The tail shank of the carbide tool to be machined is clamped in the base clamping unit, and a non-contact radial support boundary and a tail shank axial buffer boundary are established for the overhanging machining section of the carbide tool to be machined. Before and during the grinding of the overhanging section by the diamond grinding wheel, the grinding contact area is cooled, lubricated and chip removed by the cooling and lubricating medium, and the spraying state of the cooling and lubricating medium is adjusted according to the chip removal state. The local bending support state is determined based on the axial overhang position of the carbide tool to be machined, the target groove geometry, the non-contact radial support boundary, and the tail shank axial buffer boundary, and the partition linkage grinding control data is generated based on the local bending support state. During the grinding process, the grinding process status data of the overhanging section is collected. Based on the grinding process status data, the bending compensation amount, thermal expansion compensation amount and workpiece spindle speed correction amount are generated. The bending compensation amount and thermal expansion compensation amount are merged to form the feed correction amount, which is then superimposed on the zone linkage grinding control data. After the grinding of a single carbide tool is completed, the dimensional deviation data and surface morphology data of the machined surface are obtained. The dimensional deviation data, surface morphology data, support boundary data, cooling spray data and grinding process data are combined into a single-piece process record. Based on the single-piece process record, the trajectory parameter boundary and compensation parameter boundary of the next carbide tool of the same specification or a carbide tool of a nearby specification are updated.

[0008] As a preferred embodiment of the present invention, the ratio of the overhang length to the outer diameter of the carbide tool to be processed is not less than 10; the overhang processing section includes a groove-shaped area to be ground and an unground support area, a non-contact radial support boundary acts on the unground support area, and a diamond grinding wheel acts on the groove-shaped area to be ground.

[0009] Furthermore, establishing the non-contact radial support boundary and the tailstock axial buffer boundary includes: The overhanging section passes through the non-contact radial guide unit. The air supply state of the non-contact radial guide unit is adjusted based on the radial clearance measured before grinding. The non-contact radial support boundary acting on the overhanging section is determined by the radial clearance and the air supply state. The excitation state of the magnetorheological axial buffer unit is adjusted based on the axial preload of the tailstock, and the axial buffer boundary of the tailstock is determined by the excitation state.

[0010] The non-contact radial guide unit includes a gas static pressure guide sleeve with an open guide window, which avoids the diamond grinding wheel and the grinding contact area; the air supply state includes guide air pressure, zoned throttling state and exhaust state, and the non-contact radial support boundary is jointly determined by the radial clearance, guide air pressure and zoned throttling state.

[0011] As a preferred embodiment of the present invention, the magnetorheological axial buffer unit includes an annular shearing cavity connected in series with the base clamping unit, an excitation coil disposed outside the annular shearing cavity, and a magnetorheological medium disposed inside the annular shearing cavity; the excitation state is adjusted according to the axial preload of the tailstock, the rate of change of the grinding normal force, and the rate of change of the radial displacement, so that the axial buffer boundary of the tailstock is limited to a preset axial micro-displacement range.

[0012] As a preferred embodiment of the present invention, the cooling and lubricating medium includes a water-based grinding fluid sprayed by the chip removal cooling branch and an atomized lubricating flow sprayed by the low-temperature micro-lubrication branch; the atomized lubricating flow contains a low-temperature gas-liquid medium and lamellar solid lubricating particles; the chip discharge state is obtained by optical turbidity detection, image detection or acoustic emission detection; when the chip discharge state indicates an increase in chip retention, the water-based grinding fluid spray flow rate is increased or the water-based grinding fluid spray direction is changed, and the lateral spray component generated by the low-temperature micro-lubrication branch on the overhanging section is reduced.

[0013] Furthermore, the generation of zoned linkage grinding control data includes: Establish an axial position sequence along the central axis of the carbide cutting tool to be machined; The local bending support state is determined based on the distance from each axial position to the base clamping unit in the axial position sequence, the non-contact radial support boundary, the tail shank axial buffer boundary, and the target groove geometry. Based on the local bending support state, the continuous grinding trajectory is decomposed into multiple grinding operation intervals with overlapping transition zones, and radial depth of cut, axial feed rate, axial movement data of the carbide tool to be processed, and rotation angle data of the carbide tool to be processed are assigned to each grinding operation interval. The radial depth of cut and the axial feed rate of each grinding operation zone are determined based on the local bending support state. The radial depth of cut and the axial feed rate are positively correlated with the local bending support state and are smoothly connected in the overlapping transition zone of adjacent grinding operation zones.

[0014] Furthermore, the grinding process status data includes radial displacement, grinding normal force, grinding contact temperature, cooling spray parameters, and workpiece spindle vibration data. Before generating bending compensation, thermal expansion compensation, and workpiece spindle speed correction, guide clearance baseline correction is performed on the radial displacement, no-load drift correction is performed on the grinding normal force, spray shielding compensation is performed on the grinding contact temperature, and workpiece spindle vibration data is processed by eliminating the workpiece spindle idle frequency band. The corrected grinding process status data are then aligned with the same time reference.

[0015] As a preferred technical solution of the present invention, the bending compensation amount is obtained based on the radial displacement and the grinding normal force; the thermal expansion compensation amount is obtained based on the grinding contact temperature, cooling spray parameters and material thermophysical data; the cooling spray parameters include the flow rate of the chip removal cooling branch, the spray angle of the chip removal cooling branch, the spray flow rate of the low-temperature micro-lubrication branch and the spray angle of the low-temperature micro-lubrication branch.

[0016] As a preferred technical solution of the present invention, the process of integrating the bending compensation amount and the thermal expansion compensation amount to form the feed correction amount includes: determining the compensation direction of the bending compensation amount and the thermal expansion compensation amount in the feed direction of the diamond grinding wheel respectively; when the compensation directions are consistent, generating the feed correction amount according to a preset safety ratio; when the compensation directions are opposite and the difference exceeds a preset difference threshold, reducing the radial depth of cut in the current grinding operation range, and marking the current grinding operation range as the range to be reviewed.

[0017] As a preferred technical solution of the present invention, generating the workpiece spindle speed correction amount based on the workpiece spindle vibration data includes: extracting the frequency band of chatter energy concentration from the workpiece spindle vibration data; determining the speed avoidance direction by frequency based on the frequency band of chatter energy concentration, the current workpiece spindle speed, and the surface characteristics of the diamond grinding wheel; and generating the workpiece spindle speed correction amount under the condition that it does not exceed the allowable range of workpiece spindle speed and the allowable range of diamond grinding wheel linear speed.

[0018] As a preferred technical solution of the present invention, updating the trajectory parameter boundaries and compensation parameter boundaries of the next cemented carbide tool of the same specification or a cemented carbide tool of adjacent specifications to be machined based on the single-piece process record includes: performing quality classification on the single-piece process record, and removing single-piece process records whose dimensional deviation data or surface morphology data exceed the qualified range; performing density clustering on the retained single-piece process records, and extracting the trajectory parameters and compensation parameters corresponding to the cluster core samples; and writing the extracted trajectory parameters and compensation parameters into the parameter candidate area constrained by the safety boundary.

[0019] Specifically, before the diamond grinding wheel is about to enter the corresponding grinding operation zone, laser-assisted preheating is performed on the unprocessed surface of the carbide tool to be processed. The output energy of the laser-assisted preheating is constrained by the temperature of the preheating zone, the grinding contact temperature of the previous grinding sampling cycle or the historical grinding contact temperature of the carbide tool of the same specification, the material thermophysical data, and the jet flow rate of the low-temperature micro-lubrication branch, so that the preheating zone is kept within the temperature range that does not produce continuous melting or penetrating hot cracks.

[0020] As a preferred technical solution of the present invention, during the grinding process or between adjacent grinding operation intervals, the contour point cloud data of the working surface of the diamond grinding wheel is acquired by a line laser contour scanning unit. The contour point cloud data is registered with the nominal contour data of the diamond grinding wheel to obtain the diamond grinding wheel contour deviation data. The diamond grinding wheel contour deviation data is then converted into the diamond grinding wheel position compensation component in the partitioned linkage grinding control data.

[0021] This invention also discloses a grinding system for a large aspect ratio TCT solid head carbide cutting tool, comprising: The dual-boundary flexible support mechanism includes a base clamping unit, a magnetorheological axial buffer unit, and a non-contact radial guide unit. The base clamping unit clamps the tail shank of the carbide tool to be machined, the non-contact radial guide unit is used to establish a non-contact radial support boundary, and the magnetorheological axial buffer unit is used to establish an axial buffer boundary for the tail shank. The graded cooling and lubrication module is used to spray cooling and lubricating media into the grinding contact area and adjust the spraying state of the cooling and lubricating media according to the state of grinding debris discharge. The trajectory generation unit is used to determine the local bending support state based on the axial overhang position of the carbide tool to be machined, the target groove geometry, the non-contact radial support boundary and the tail shank axial buffer boundary, and to generate partitioned linkage grinding control data based on the local bending support state. The force and heat compensation control unit is used to receive the grinding process status data of the overhanging processing section, generate bending compensation amount, thermal expansion compensation amount and workpiece spindle speed correction amount based on the grinding process status data, and merge the bending compensation amount and thermal expansion compensation amount to form the feed correction amount, so that the feed correction amount is superimposed on the zone linkage grinding control data. The quality feedback update unit is used to receive dimensional deviation data and surface morphology data of the machined surface, and to combine the dimensional deviation data, surface morphology data, support boundary data, cooling spray data and grinding process data into a single-piece process record to update the trajectory parameter boundary and compensation parameter boundary of the next carbide tool of the same specification or a carbide tool of a nearby specification to be machined.

[0022] Compared with the prior art, the present invention has the following beneficial effects: The non-contact radial guiding unit of this invention provides a non-contact radial support boundary through an air film, enabling the overhanging machining section to obtain radial constraint during grinding, while avoiding direct scratches on the carbide outer diameter caused by ordinary mechanical stabilizers. The magnetorheological axial buffer unit adjusts the axial buffer boundary of the tail shank through the excitation state, allowing the tail shank clamping point to absorb axial stress caused by grinding impact and thermal expansion within a preset axial micro-displacement range. The non-contact radial support boundary and the tail shank axial buffer boundary are converted into a local anti-bending support state, which is further used to generate zoned linkage grinding control data. As a result, the radial depth of cut and axial feed rate are no longer determined solely by the target groove geometry, but are simultaneously affected by the current support boundary and axial position, making the material removal load near the free end and near the tail shank side more matched. The bending compensation and thermal expansion compensation are generated by different data links and then fused, which can reduce the probability that a single grinding normal force feedback will misjudge thermal expansion error as tool deflection error. Workpiece spindle vibration data is used to generate a workpiece spindle speed correction that avoids the current chatter frequency band, so that feed position compensation and frequency avoidance work together to control surface periodic vibration.

[0023] The dimensional deviation data and surface morphology data obtained after processing in this invention are not only used for qualification determination, but also combined with support boundary data, cooling spray data, and grinding process data to form a single-piece process record. After quality grading and safety boundary constraints, the single-piece process record is used to update the trajectory parameter boundaries and compensation parameter boundaries of the next carbide tool of the same specification or a carbide tool of a nearby specification to be processed, so that the batch grinding parameters can converge within a verifiable range. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a flowchart of the processing method of the present invention.

[0026] Figure 2 This is a flowchart illustrating the process of establishing the support boundaries for the dual-boundary flexible support mechanism of the present invention.

[0027] Figure 3 This is a flowchart illustrating the formation of a non-contact radial support boundary by the non-contact radial guide unit of the present invention.

[0028] Figure 4 This is a flowchart illustrating the process of adjusting the spraying state of the cooling and lubrication medium in the graded cooling and lubrication module of the present invention.

[0029] Figure 5 This is a flowchart illustrating the determination of the local bending support state according to the present invention.

[0030] Figure 6 This is a flowchart illustrating the generation of partitioned linkage grinding control data according to the present invention.

[0031] Figure 7 This is a flowchart illustrating how the force and heat compensation control unit of the present invention generates the feed correction amount.

[0032] Figure 8 This is a flowchart illustrating the generation of the workpiece spindle speed correction amount according to the present invention. Detailed Implementation

[0033] 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.

[0034] The following is in conjunction with the appendix Figures 1-8 The embodiments of the present invention will be described in detail below.

[0035] Example 1: This example discloses a grinding method for a large aspect ratio TCT solid-head carbide cutting tool, including: The tail shank of the carbide tool to be machined is clamped in the base clamping unit, and a non-contact radial support boundary and a tail shank axial buffer boundary are established for the overhanging machining section of the carbide tool to be machined. Before and during the grinding of the overhanging section by the diamond grinding wheel, the grinding contact area is cooled, lubricated and chip removed by the cooling and lubricating medium, and the spraying state of the cooling and lubricating medium is adjusted according to the chip removal state. The local bending support state is determined based on the axial overhang position of the carbide tool to be machined, the target groove geometry, the non-contact radial support boundary, and the tail shank axial buffer boundary, and the partition linkage grinding control data is generated based on the local bending support state. During the grinding process, the grinding process status data of the overhanging section is collected. Based on the grinding process status data, the bending compensation amount, thermal expansion compensation amount and workpiece spindle speed correction amount are generated. The bending compensation amount and thermal expansion compensation amount are merged to form the feed correction amount, which is then superimposed on the zone linkage grinding control data. After the grinding of a single carbide tool is completed, the dimensional deviation data and surface morphology data of the machined surface are obtained. The dimensional deviation data, surface morphology data, support boundary data, cooling spray data and grinding process data are combined into a single-piece process record. Based on the single-piece process record, the trajectory parameter boundary and compensation parameter boundary of the next carbide tool of the same specification or a carbide tool of a nearby specification are updated.

[0036] This embodiment further illustrates the groove grinding process using a slender, solid-head carbide end mill for deep cavity machining: The carbide cutting tool to be machined includes a tail shank and an overhang machining section. The tail shank is used to be held by the base clamping unit. The overhang machining section includes a groove-shaped area to be ground and an unground support area. The groove-shaped area to be ground is used to form helical grooves, cutting edges, and clearance angles by grinding with a diamond wheel. The unground support area is used to pass through a non-contact radial guide unit and receive radial support. The ratio of the overhang length to the outer diameter of the carbide cutting tool to be machined is not less than 10.

[0037] In this embodiment, a slender solid head carbide end mill is selected. Solid head carbide drilling tools, solid head carbide grooving tools, and other slender rotary tools can be processed according to the same process.

[0038] In this embodiment, the outer diameter of the carbide tool to be machined is 4 mm, the overhang length is 120 mm, and the ratio of the overhang length to the outer diameter is 30. The target groove geometry includes four helical grooves with a groove depth of 1.2 mm to 1.8 mm, a helix angle of 30°, and a cutting edge width of 0.1 mm to 0.3 mm. The linear velocity of the diamond grinding wheel is set to 20 m / s to 30 m / s, and the rotational speed of the carbide tool to be machined is set to 5000 r / min to 12000 r / min.

[0039] In practice, the specific production values ​​are determined by the outer diameter of the carbide cutting tool to be processed, the material grade, the grit size of the diamond grinding wheel, and the machine tool capability.

[0040] Before machining, the operator or automatic feeding system places the carbide tool to be machined in the loading position. The control system reads the design file of the carbide tool to be machined. The design file of the carbide tool to be machined can be at least one of the following: a 3D model file, a tool process table, or a CNC machining program. The design file of the carbide tool to be machined must include at least the outer diameter, overhang length, number of flutes, flute depth, helix angle, cutting edge width, clearance angle, and grinding allowance. The control system also reads the carbide material data. The carbide material data must include at least the material grade, hardness range, coefficient of thermal expansion, thermal conductivity, and elastic modulus range. If there is a historical record of the same specification of carbide tool to be machined in the enterprise's internal process system, the control system reads the trajectory parameter boundaries and compensation parameter boundaries simultaneously; if there is no historical record of the same specification of carbide tool to be machined, the control system reads the trajectory parameter boundaries and compensation parameter boundaries of adjacent specifications of carbide tool to be machined, and forms initial candidate boundaries based on the outer diameter, overhang length, flute depth, and material thermophysical property data.

[0041] Adjacent-specification carbide cutting tools refer to those that meet the same calibration or conversion relationship as the current carbide cutting tool in terms of outer diameter, overhang length, flute depth, material thermophysical properties, and local bending support state. If two carbide cutting tools have similar outer diameters and overhang lengths, but their flute depths result in significant differences in cross-sectional weakening, these two tools will not be treated as adjacent-specification tools. If two carbide cutting tools have similar outer diameters and flute depths, but their material thermophysical properties are significantly different, these two tools will also not be treated as adjacent-specification tools. The parameters of adjacent-specification carbide cutting tools only enter the parameter candidate area and do not directly overwrite the current production parameters.

[0042] After loading, the base clamping unit clamps the tail shank. The base clamping unit is one of a spring collet, hydraulic collet, precision chuck, or heat-shrinkable clamping sleeve. To ensure that the central axis of the tail shank is aligned with the machine tool workpiece spindle axis, the control system first performs a low-speed rotation detection. During the low-speed rotation detection, the radial displacement detection unit or external cylindrical probe measures the rotational runout of the tail shank. If the rotational runout exceeds the preset clamping range, the control system prompts for re-clamping or automatically performs clamp release and re-clamping. If the rotational runout is within the allowable range, the control system records the axial preload of the tail shank. The axial preload of the tail shank is obtained from the pressure feedback of the clamping driver, the axial force sensor, or the calibrated relationship between clamping stroke and clamping force.

[0043] A magnetorheological axial buffer unit is positioned between the base clamping unit and the machine tool workpiece spindle support. The magnetorheological axial buffer unit includes an annular shearing cavity, an excitation coil, and a magnetorheological medium. The fixed side of the annular shearing cavity is connected to the machine tool workpiece spindle support, and the movable side is connected to the base clamping unit. The magnetorheological medium is located within the annular shearing cavity. When the excitation coil is energized, it alters the shear yield state of the magnetorheological medium, allowing the base clamping unit to achieve limited axial micro-displacement relative to the machine tool workpiece spindle support. The magnetorheological axial buffer unit prevents macroscopic movement of the tail shank. Its function is to absorb the axial impact during grinding contact and the clamping stress changes caused by thermal expansion and contraction. The control system sets the initial excitation state based on the tail shank axial preload. A larger tail shank axial preload results in higher damping and equivalent stiffness of the magnetorheological axial buffer unit corresponding to the initial excitation state; a smaller tail shank axial preload results in a slightly lower damping and equivalent stiffness of the magnetorheological axial buffer unit corresponding to the initial excitation state, to avoid impact amplification when clamping is insufficient.

[0044] In this embodiment, the axial micro-displacement range of the magnetorheological axial buffer unit is set to 2 μm to 20 μm, the excitation current is set to 0.2 A to 1.5 A, and the volume fraction of the magnetorheological medium is set to 20% to 40%. During grinding, if the rate of change of the grinding normal force and the rate of change of the radial displacement increase simultaneously, the control system increases the excitation current to improve the damping level corresponding to the axial buffer boundary of the tailstock; if the grinding normal force is stable and the rate of change of the radial displacement decreases, the control system maintains or reduces the excitation current to reduce the axial constraint strength corresponding to the axial buffer boundary of the tailstock.

[0045] A non-contact radial guide unit is positioned in the unground support area of ​​the overhang machining section. The non-contact radial guide unit includes a gas static pressure guide sleeve. The gas static pressure guide sleeve has an open guide window. This open guide window faces the working side of the diamond grinding wheel, allowing the diamond grinding wheel to cut into the groove area to be ground without interference from the gas static pressure guide sleeve. Multiple air supply zones are provided on the inner circumferential surface of the gas static pressure guide sleeve. Each air supply zone supplies clean compressed gas to the radial clearance through a throttling orifice, microporous material, or a slit throttling structure. The gas static pressure guide sleeve also has an exhaust channel, allowing the airflow to carry a small amount of grinding debris and coolant mist away from the unground support area, preventing grinding debris from entering the radial clearance and causing scratches.

[0046] The inner diameter of the gas static pressure guide sleeve is 10 μm to 30 μm larger than the outer diameter of the carbide tool to be machined. The radial clearance on one side measured before grinding is 5 μm to 15 μm, the guide air pressure is 0.3 MPa to 0.7 MPa, the dew point temperature of the compressed gas is not higher than -20 ℃, and the filtration accuracy of the compressed gas is not greater than 1 μm. The circumferential angle range of the open guide window is 90° to 120°, covering the entire working angle of the diamond wheel's entry. If the radial clearance is less than the preset minimum value, the control system will not allow the diamond wheel to enter the grinding contact area and will prompt to check the outer diameter of the carbide tool to be machined or the coaxiality of the gas static pressure guide sleeve. If the radial clearance is greater than the preset maximum value, the control system will increase the guide air pressure or adjust the position of the non-contact radial guide unit; if the adjustment still cannot meet the non-contact radial support boundary, the control system will reduce the radial entry depth of the free end corresponding to the grinding working area.

[0047] Before grinding, the control system performs radial clearance detection. Radial clearance detection employs one of the following methods: capacitive displacement sensor detection, optical displacement sensor detection, gas film pressure and supply flow rate inversion detection, or standard bar calibration detection. When using a capacitive displacement sensor, the sensor is positioned on the end face or inner circumference of the gas static pressure guide sleeve, detecting the radial offset of the overhanging machining section relative to the center of the gas static pressure guide sleeve. When using gas film pressure and supply flow rate inversion detection, the control system reads the pressure and flow rate of each supply zone after the supply pressure stabilizes, and obtains the radial clearance through a pre-calibrated relationship between pressure, flow rate, and clearance. When using standard bar calibration detection, a standard bar with a known outer diameter is inserted into the gas static pressure guide sleeve to establish a reference relationship between the center of the gas static pressure guide sleeve and the machine tool coordinate system. The measured value of the carbide tool to be machined after entering the gas static pressure guide sleeve is then compared with this reference relationship.

[0048] The control system determines the non-contact radial support boundary based on radial clearance, guide air pressure, and zoned throttling conditions. The non-contact radial support boundary is represented by support stiffness level, lateral force tolerance range, or normalized support state. In this embodiment, the non-contact radial support boundary is divided into three levels: low support, medium support, and high support, and is numerically characterized within the control system. The control system determines the tailstock axial buffer boundary based on the excitation state of the magnetorheological axial buffer unit. The tailstock axial buffer boundary characterizes the tailstock's ability to absorb impact and thermal expansion within the axial micro-displacement range. The non-contact radial support boundary and the tailstock axial buffer boundary jointly enter the process of determining the local bending support state.

[0049] The local bending support state characterizes the ability of each axial position on the overhanging machining section to resist bending caused by the normal force of diamond wheel grinding. The control system establishes an axial position sequence along the central axis of the carbide tool to be machined. The axial position sequence is established at fixed intervals, or with denser position points near the free end of the carbide tool, near the edge of the open guide window, in areas of varying groove depth, and in overlapping transition zones. For each axial position, the control system reads the distance from the corresponding axial position to the base clamping unit, the distance from the corresponding axial position to the effective support area of ​​the non-contact radial guide unit, the non-contact radial support boundary, the shank axial buffer boundary, and the target groove geometry. The control system obtains the local bending support state through a pre-calibrated table or a simplified mechanical model.

[0050] The pre-calibration table is established by applying known lateral forces and measuring radial displacements using a standard carbide rod under different overhang lengths, guide air pressures, and excitation conditions. The simplified mechanical model approximates the overhanging machining section as a slender beam constrained by the tailstock clamping and the air film support of the non-contact radial guide unit. Regardless of whether the pre-calibration table or the simplified mechanical model is used, the input for the local bending support state comes from the actual support boundary, rather than fixed empirical values. The output of the local bending support state is the bending grade or normalized bending value corresponding to the axial position. The output of the local bending support state is used by the trajectory generation unit to generate zoned linkage grinding control data.

[0051] The graded cooling and lubrication module includes a chip removal cooling branch and a low-temperature micro-lubrication branch. The nozzles of the chip removal cooling branch are positioned in front of the grinding contact area. This branch sprays water-based grinding fluid, which tangentially washes the area about to enter the grinding contact zone along the surface of the carbide tool and the diamond wheel. The main function of the chip removal cooling branch is to remove large grinding chips, reduce secondary compression of the chips between the diamond wheel and the carbide surface, and create basic convection heat transfer. Since the chip removal cooling branch does not target high-pressure vertical impact overhang machining sections, the nozzles are preferably flat fan-shaped nozzles, low-angle attached nozzles, or multi-hole weak-impact nozzles.

[0052] The nozzle of the cryogenic micro-lubrication branch is positioned near the grinding contact area. The cryogenic micro-lubrication branch includes a cryogenic gas-liquid medium supply source, a micro-lubrication supplier, a layered solid lubricant particle carrier liquid supplier, a particle delivery branch, a short mixing chamber, and nozzles. The particle delivery branch is used to transport the layered solid lubricant particles and mix them with the cryogenic gas-liquid medium at the nozzle tip. The cryogenic micro-lubrication branch sprays an atomized lubricating flow containing the cryogenic gas-liquid medium and the layered solid lubricant particles. The cryogenic gas-liquid medium is one of liquid nitrogen, cryogenic nitrogen gas, liquid carbon dioxide, a cryogenic carbon dioxide gas-liquid mixture, or cooled compressed air. The layered solid lubricant particles are one of graphene, molybdenum disulfide, hexagonal boron nitride, or layered graphite. The layered solid lubricant particles are dispersed in a small amount of base oil, water-based carrier liquid, or volatile carrier liquid, or mixed with the cryogenic gas-liquid medium at the nozzle tip via the particle delivery branch. To reduce the risk of pipeline blockage and low-temperature freezing, the low-temperature gas-liquid medium and the lubricating particle carrier liquid are preferably combined in a short mixing chamber at the nozzle tip.

[0053] In practice, the flow rate of the water-based grinding fluid in the chip removal cooling branch is 0.5 L / min to 3 L / min, and the spray angle is 15° to 45° relative to the axis of the carbide tool to be machined. The flow rate of the low-temperature micro-lubrication branch is 5 L / min to 20 L / min, the mass fraction of lamellar solid lubricating particles in the carrier fluid is 0.05% to 1%, and the spray angle of the low-temperature micro-lubrication branch is 0° to 30° relative to the tangential direction of the diamond grinding wheel. If the outer diameter of the carbide tool to be machined is less than 3 mm, the control system reduces the spray component of the low-temperature micro-lubrication branch perpendicular to the overhanging machining section; if the chip removal status shows an increase in chip retention, the control system prioritizes adjusting the chip removal cooling branch, rather than simply increasing the flow rate of the low-temperature micro-lubrication branch.

[0054] The chip removal cooling branch outputs the chip discharge status. The chip discharge status is obtained through optical turbidity detection, image detection, acoustic emission detection, or coolant recirculation filter load detection. Optical turbidity detection determines chip concentration by detecting changes in light transmittance in the recirculation liquid or splash area. Image detection observes chip accumulation and jet morphology before and after the grinding contact area using a camera unit. Acoustic emission detection determines chip retention based on the high-frequency acoustic emission characteristics generated during secondary chip compression. Coolant recirculation filter load detection determines the chip discharge rate by changes in pressure difference within the recirculation filter structure.

[0055] When the chip removal status indicates increased chip retention, the control system prioritizes increasing the flow rate of the water-based grinding fluid in the chip removal cooling branch or changing the spray direction of the water-based grinding fluid to remove the chips from the grinding contact area. Simultaneously, the control system adjusts the spray angle of the low-temperature micro-lubrication branch, ensuring that more atomized lubricating fluid enters the grinding contact area tangentially along the diamond wheel, reducing the lateral spray component of the direct vertical impact overhang machining section. Through this coordinated action, cooling and lubrication are no longer determined solely by a fixed flow rate and nozzle angle, but are adjusted based on the chip removal status and the support boundary of the overhang machining section.

[0056] The trajectory generation unit generates zoned linkage grinding control data based on the target groove geometry, local bending support state, and historical trajectory parameter boundaries. The zoned linkage grinding control data includes at least the transverse feed data, longitudinal feed data, axial movement data of the carbide tool to be machined, and rotation angle data of the carbide tool to be machined relative to the diamond grinding wheel.

[0057] For CNC tool grinders with five or six axes, the trajectory generation unit converts the zoned linkage grinding control data into motion commands for the corresponding physical axes. The converted motion commands still focus on the grinding position, grinding angle, and grinding depth of the diamond grinding wheel relative to the central axis of the carbide tool being machined.

[0058] The trajectory generation unit decomposes the continuous grinding trajectory into multiple grinding operation intervals. Each grinding operation interval corresponds to an axial position range. An overlapping transition zone is set between adjacent grinding operation intervals. Within the overlapping transition zone, the radial depth of cut and axial feed rate transition smoothly according to curves. The smooth curve can be a linear transition, a spline transition, or a piecewise acceleration / deceleration transition. The purpose of setting the overlapping transition zone is to avoid abrupt changes in grinding normal force and surface marks caused by jumping directly from one depth of cut to another.

[0059] For grinding operations with low local bending support, the trajectory generation unit allocates a smaller radial depth of cut or a lower axial feed rate. These areas are typically located near the free end of the carbide tool being machined, away from the effective support area of ​​the non-contact radial guide unit, or in locations where the groove depth is large, reducing the cross-sectional bending resistance. Conversely, for grinding operations with high local bending support, the trajectory generation unit allocates a larger radial depth of cut or a higher axial feed rate. These areas are typically close to the base clamping unit or the effective support area of ​​the non-contact radial guide unit. Through this allocation, the free end of the carbide tool being machined will not experience excessive tool deflection due to using the same feed load as the tailstock side.

[0060] In some embodiments, the continuous grinding trajectory is decomposed axially into three grinding operation zones. The first grinding operation zone, near the free end, employs a radial depth of cut of 0.003 mm to 0.008 mm and an axial feed rate of 10 mm / min to 25 mm / min. The second grinding operation zone, located in the middle, employs a radial depth of cut of 0.006 mm to 0.012 mm and an axial feed rate of 20 mm / min to 40 mm / min. The third grinding operation zone, near the tailstock, employs a radial depth of cut of 0.01 mm to 0.02 mm and an axial feed rate of 30 mm / min to 60 mm / min. A 5 mm to 15 mm overlap transition zone is provided between adjacent grinding operation zones. In practice, the actual values ​​are determined by the machine tool rigidity, the material of the carbide tool to be machined, and the geometry of the target groove.

[0061] Before grinding begins, the force and heat compensation control unit performs data baseline calibration. Radial displacement baseline correction is performed when the diamond wheel is not in contact with the carbide tool being machined and the air supply from the non-contact radial guide unit is stable. The control system records the radial position of the overhang machining section under no-load conditions as the radial displacement baseline. Grinding normal force no-load drift correction is performed when the diamond wheel spindle is idling and the feed axis is not engaged. The control system records the diamond wheel spindle idling load and the zero-point drift of the force sensor as the grinding normal force correction value. Grinding contact temperature spray obstruction compensation is performed when the chip removal cooling branch and the low-temperature micro-lubrication branch are open but the diamond wheel is not engaged. The control system records the obstruction effect of the spray on infrared thermography or thermal imaging thermography. Workpiece spindle vibration idling frequency band elimination is performed when the workpiece spindle is idling. The control system records the frequency bands generated by the workpiece spindle and the workpiece spindle motor itself. During grinding, the above-mentioned idling frequency bands are first eliminated from the workpiece spindle vibration data. Radial displacement, grinding normal force, grinding contact temperature, and workpiece spindle vibration data at different sampling frequencies are aligned to the same time reference after correction.

[0062] During the grinding process, the radial displacement detection unit collects the radial displacement of the overhanging machining section in real time. The radial displacement reflects the deviation trend of the overhanging machining section relative to the theoretical centerline. The grinding normal force detection unit collects the grinding normal force exerted by the diamond grinding wheel on the carbide tool being machined. This unit can be one of the following: a diamond grinding wheel spindle flange force sensor, a diamond grinding wheel spindle current inversion unit, a piezoelectric force measurement unit, or a feed axis servo load estimation unit. The grinding contact temperature detection unit collects the temperature of the grinding contact area. This unit can be one of the following: an infrared temperature measurement unit, a thermal imaging unit, a thin-film thermocouple, or a temperature estimation unit based on cooling jets and grinding power. The workpiece spindle vibration detection unit collects workpiece spindle vibration data. This unit can be one of the following: a workpiece spindle housing acceleration sensor, an acoustic emission sensor, or a workpiece spindle current fluctuation detection unit.

[0063] The force and heat compensation control unit inputs radial displacement and grinding normal force into the bending compensation generation process. The bending compensation generation process employs a lookup table model, a rule model, a regression model, or a neural network model.

[0064] To ensure feasibility, this embodiment employs a combination of lookup table model and rule correction. The control system pre-stores bending compensation tables for different outer diameters, overhang lengths, non-contact radial support boundaries, and grinding normal forces. These bending compensation tables are calibrated using standard carbide rods. During grinding, the control system first obtains the basic compensation value from the bending compensation table based on the outer diameter, overhang length, axial position, and non-contact radial support boundary, and then corrects it based on the real-time radial displacement change rate and grinding normal force change rate. If both the radial displacement change rate and the grinding normal force change rate increase simultaneously, it indicates an increased tool deflection tendency in the current grinding operation range, and the bending compensation amount increases. If the grinding normal force increases but the radial displacement does not increase synchronously, it indicates that the current error may not primarily originate from bending tool deflection, and the bending compensation amount does not directly increase significantly.

[0065] The thermal compensation control unit inputs grinding contact temperature, cooling jet parameters, and material thermophysical property data into the thermal expansion compensation generation process. Cooling jet parameters include the flow rate of the chip removal cooling branch, the jet angle of the chip removal cooling branch, the flow rate of the low-temperature micro-lubrication branch, and the jet angle of the low-temperature micro-lubrication branch. The thermal expansion compensation generation process employs temperature zone lookup tables, simplified thermal expansion models, or empirical rule models.

[0066] This embodiment employs a temperature-zone lookup table method. The control system divides the overhanging machining section into multiple temperature-affected zones based on its axial position. Each temperature-affected zone records the grinding contact temperature, the flow rate of the low-temperature micro-lubrication branch, the flow rate of the chip removal cooling branch, and material thermophysical property data. The control system estimates the thermal expansion and contraction trend of the corresponding grinding operation area based on the temperature level and duration of each temperature-affected zone. If the grinding contact temperature rises and the duration exceeds the preset thermal effect time, the thermal expansion and contraction compensation increases; if the low-temperature micro-lubrication branch has sufficient flow rate and the temperature drops rapidly, the thermal expansion and contraction compensation decreases. The thermal expansion and contraction compensation is used to correct for the relative positional changes between the diamond grinding wheel and the carbide cutting tool being machined due to thermal expansion and contraction.

[0067] For example, the bending compensation boundary is set to -8 μm to +8 μm, the thermal expansion compensation boundary is set to -5 μm to +5 μm, and the single feed correction boundary is set to -4 μm to +4 μm. If the bending compensation or thermal expansion compensation exceeds the corresponding boundary, the control system will not perform the corresponding over-limit compensation and will mark the current grinding operation range as a region to be reviewed. If the feed correction reaches the boundary within three consecutive sampling cycles, the control system will reduce the radial depth of cut in the current grinding operation range and record the compensation boundary trigger information.

[0068] The force-thermal compensation control unit performs consistency checks on the bending compensation and thermal expansion compensation amounts. If the bending compensation and thermal expansion compensation amounts are aligned in the diamond wheel feed direction, the control system generates a feed correction amount according to a preset safety ratio. This preset safety ratio limits the magnitude of a single correction, preventing overcompensation caused by sensor noise and model errors. If the bending compensation and thermal expansion compensation amounts are in opposite directions and the difference exceeds a preset difference threshold, the control system does not directly perform large-scale compensation. Instead, it reduces the radial penetration depth of the current grinding operation area, marks the current grinding operation area as a verification area, and re-detects it in subsequent finish grinding or feedless finishing processes. Feedless finishing processes refer to processes where the diamond wheel performs surface finishing and dimensional verification of the current grinding operation area without increasing the radial penetration depth. The marking of the verification area is also entered into the single-piece process record, and the quality feedback update unit reduces the weight of the verification area data or removes it directly when updating parameters.

[0069] Workpiece spindle vibration data is entered into the workpiece spindle speed correction process. The force and heat compensation control unit first performs frequency band analysis on the workpiece spindle vibration data, eliminating the workpiece spindle idling frequency band and extracting the energy concentration frequency band generated by grinding contact. The energy concentration frequency band is used as the current chatter frequency band. The control system compares the current chatter frequency band, the current workpiece spindle speed, the diamond wheel surface characteristic passing frequency, and the machine tool structure's inherent frequency band. If the current chatter frequency band is close to the machine tool structure's inherent frequency band, the control system generates a workpiece spindle speed correction amount. The workpiece spindle speed correction amount is constrained by the allowable speed range of the workpiece spindle, the allowable linear speed range of the diamond wheel, and the cooling and lubrication capacity. If increasing the workpiece spindle speed will cause the current chatter frequency band to move away from the machine tool structure's inherent frequency band, the workpiece spindle speed correction amount is positive; if decreasing the workpiece spindle speed is more conducive to avoiding the machine tool structure's inherent frequency band, the workpiece spindle speed correction amount is negative. The workpiece spindle speed correction amount can be executed synchronously with the feed correction amount, or the workpiece spindle speed correction can be executed first, and then the feed correction can be executed according to the corrected vibration state.

[0070] After a single piece of carbide cutting tool is ground, the quality feedback update unit controls the scanning unit to scan the machined surface. The scanning unit is one of the following: a confocal chromatic aberration sensor, a white light interferometer, a line laser contour sensor, a structured light sensor, or a high-magnification machine vision unit. The scanning content includes the outer diameter contour, groove bottom contour, cutting edge contour, clearance angle contour, and surface texture. Dimensional deviation data includes outer diameter deviation, groove bottom depth deviation, cutting edge width deviation, core thickness deviation, and axial runout deviation. Surface morphology data includes periodic vibration marks, roughness characteristics, localized burn characteristics, suspected hot crack characteristics, and secondary scratches from grinding debris.

[0071] In some preferred embodiments, the acceptable range for outer diameter deviation is set to -3 μm to +3 μm, the acceptable range for groove bottom depth deviation is set to -5 μm to +5 μm, the acceptable range for cutting edge width deviation is set to -5 μm to +5 μm, the acceptable upper limit for surface roughness is set to 0.12 μm, and the acceptable upper limit for periodic vibration amplitude is set to 2 μm. If the dimensional deviation data or surface morphology data exceeds the acceptable range, the single-piece process record is entered into the abnormal sample area.

[0072] The quality feedback update unit combines dimensional deviation data, surface morphology data, support boundary data, cooling spray data, and grinding process data into a single-piece process record. Support boundary data includes radial clearance, guide air pressure, zoned throttling status, tailstock axial preload, and excitation status. Cooling spray data includes chip removal cooling branch flow rate, chip removal cooling branch spray angle, chip discharge status, low-temperature micro-lubrication branch flow rate, and low-temperature micro-lubrication branch spray angle. Grinding process data includes zoned linkage grinding control data, feed correction, workpiece spindle speed correction, radial displacement, grinding normal force, grinding contact temperature, and workpiece spindle vibration data. The single-piece process record also includes markers for areas requiring verification, sensor anomalies, and operational interventions.

[0073] The quality feedback update unit performs quality grading on individual process records. Individual process records with both dimensional deviation and surface topography data within acceptable ranges are entered into the updateable sample area. Individual process records with dimensional deviation or surface topography data exceeding acceptable ranges are entered into the abnormal sample area. Individual process records where sensor failure, nozzle blockage, diamond wheel profile exceeding limits, or process interruption due to manual intervention are also entered into the abnormal sample area. Data in the abnormal sample area is used for fault analysis but does not directly update the trajectory parameter boundaries and compensation parameter boundaries for the next carbide tool to be machined.

[0074] The single-piece process records in the updatable sample area are grouped according to the outer diameter, overhang length, groove depth, material thermophysical properties, and local bending support status of the carbide tool to be machined. For carbide tools of the same specification or adjacent specifications, the quality feedback update unit performs density clustering to extract the trajectory parameters and compensation parameters corresponding to the cluster core samples. The cluster core samples represent parameter combinations that can stably obtain qualified dimensions and surface morphology under similar support boundaries, similar cooling spray conditions, and similar grinding loads. The extracted trajectory parameters and compensation parameters do not directly overwrite the current production parameters but are written into the parameter candidate area constrained by safety boundaries.

[0075] Safety boundaries include machine tool motion axis velocity boundaries, machine tool motion axis acceleration boundaries, diamond grinding wheel linear velocity boundaries, minimum radial clearance of non-contact radial guide units, maximum axial micro-displacement of magnetorheological axial buffer units, cryogenic gas-liquid medium flow rate boundaries, lateral jet component boundaries of chip removal cooling branches, material thermal load boundaries, and process card boundaries. Before machining the next carbide tool of the same specification or a carbide tool of an adjacent specification, the trajectory generation unit reads the trajectory parameter boundaries from the parameter candidate area, and the force-thermal compensation control unit reads the compensation parameter boundaries from the parameter candidate area. These are then combined with the real-time support boundaries of the next carbide tool to be machined to generate new zoned linkage grinding control data and compensation limit ranges.

[0076] Example 2: This example adds laser-assisted preheating to Example 1. Laser-assisted preheating is suitable for machining scenarios where the cemented carbide grains are fine, the hardness is high, the groove is deep, or the peak value of the grinding normal force is high during the initial cutting stage of the diamond wheel. The purpose of laser-assisted preheating is not to melt the surface of the cemented carbide tool to be machined, nor to form an ablation groove, but to adjust the local thermal state of the unmachined surface of the cemented carbide tool for a short time before the diamond wheel cuts in, thereby reducing the peak value of the grinding normal force during the initial cutting of the diamond wheel.

[0077] The laser-assisted preheating unit is positioned in front of the diamond wheel's cutting path. This unit includes a laser generator, an optical path adjustment assembly, a temperature measurement assembly, and a safety interlock assembly. The optical path adjustment assembly projects the laser beam onto the unmachined surface of the carbide tool that the diamond wheel is about to cut into. The temperature measurement assembly detects the temperature of the preheating area. The safety interlock assembly shuts off the laser output in case of abnormal temperature readings, abnormal cooling / lubrication, abnormal diamond wheel positioning, or abnormal air supply from the non-contact radial guide unit.

[0078] The output energy of laser-assisted preheating is constrained by the preheating zone temperature, the grinding contact temperature of the previous grinding sampling cycle or the historical grinding contact temperature of the same specification carbide tool to be machined, material thermophysical data, and the jet flow rate of the low-temperature micro-lubrication branch. The control system sets an upper limit for the preheating zone temperature. This upper limit must not reach the temperature range that would cause continuous melting, ablation pits, or through-cracks on the carbide surface. If the temperature sensing component detects that the preheating zone temperature is close to the upper limit, the control system reduces the laser output or shuts down laser-assisted preheating. If the jet flow rate of the low-temperature micro-lubrication branch is insufficient or the chip removal status of the chip removal cooling branch is abnormal, the control system will not activate laser-assisted preheating.

[0079] For example, the laser-assisted preheating unit uses a fiber laser with a wavelength of 1064 nm, an output power set to 5 W to 50 W, a preheating spot diameter set to 0.1 mm to 0.5 mm, and a preheating zone temperature controlled between 200 ℃ and 500 ℃. If the grinding contact temperature exceeds 600 ℃, the control system shuts down the laser-assisted preheating and reduces the radial depth of cut in the current grinding operation zone. In practice, the actual values ​​are determined by the carbide grade, diamond wheel grit size, cooling capacity, and machining tolerances.

[0080] Before the diamond grinding wheel enters the corresponding grinding operation zone, the trajectory generation unit reads the laser-assisted preheating status. The laser-assisted preheating status includes whether it is activated, the axial position of the preheating area, the preheating duration, the preheating temperature level, and the jet response of the low-temperature micro-lubrication branch. For grinding operation zones where the laser-assisted preheating status is stable and the upper temperature limit has not been triggered, the trajectory generation unit increases the axial feed rate of the initial entry segment or reduces the bending compensation safety margin of the initial entry segment within the allowable range of the trajectory parameter boundaries. For grinding operation zones where laser-assisted preheating is not activated, preheating is stopped, or the temperature is close to the upper limit, the trajectory generation unit uses the conservative trajectory parameters from Example 1.

[0081] The thermal compensation control unit adds a preheating marker in laser-assisted preheating scenarios. This marker is then incorporated into the thermal expansion compensation generation process. If the preheating zone temperature rises, but the low-temperature micro-lubrication branch can bring the grinding contact temperature back to the target range after the diamond wheel enters, the thermal expansion compensation is generated according to normal rules. If the preheating zone temperature rises and the grinding contact temperature remains above the target range after entry, the thermal expansion compensation increases, and the current grinding operation zone is marked as a thermal load verification zone. The thermal load verification zone is entered into the single-piece process record, and the quality feedback update unit reduces the weight of the corresponding data in the thermal load verification zone when updating parameters.

[0082] The cryogenic micro-lubrication branch adjusts the spray pattern according to the laser-assisted preheating status. If laser-assisted preheating is activated, the cryogenic micro-lubrication branch provides a stable tangential atomized lubricating flow at the diamond wheel entry point, allowing the cryogenic gas-liquid medium to absorb heat near the grinding contact area and enabling lamellar solid lubricating particles to enter between the abrasive grains and the carbide surface. If the temperature in the preheating area approaches its upper limit, the control system prioritizes reducing the laser output rather than simply increasing the cryogenic gas-liquid medium spray flow rate to avoid excessive lateral disturbance to the overhanging machining section caused by the cryogenic jet flow.

[0083] The processing flow in this embodiment is as follows: After the carbide tool to be machined is clamped, the double-boundary flexible support mechanism establishes a non-contact radial support boundary and a tailstock axial buffer boundary. The trajectory generation unit generates initial zoned linkage grinding control data based on the local bending support state. The chip removal cooling branch and the low-temperature micro-lubrication branch are activated and the spray baseline calibration is completed. The laser-assisted preheating unit reads the position of the grinding operation zone to be cut into and preheats the unmachined surface of the carbide tool to be machined for a short time. The temperature measurement component provides real-time feedback on the temperature of the preheating area. If the temperature of the preheating area is within the allowable range, the diamond wheel enters the grinding contact zone; if the temperature of the preheating area exceeds the allowable range, the laser-assisted preheating unit is turned off, and the trajectory generation unit reduces the radial depth of cut in the corresponding grinding operation zone. During grinding, the force and heat compensation control unit simultaneously processes radial displacement, grinding normal force, grinding contact temperature, and workpiece spindle vibration data. After machining is completed, the quality feedback update unit determines whether the laser-assisted preheating parameters have entered the parameter candidate area based on dimensional deviation data, surface morphology data, and preheating marks.

[0084] In this embodiment, laser-assisted preheating is linked with graded cooling and lubrication, trajectory generation, and force-thermal compensation to form a data linkage. The preheating zone temperature, the grinding contact temperature of the previous grinding sampling cycle or the historical grinding contact temperature of the same specification carbide tool to be machined, the low-temperature micro-lubrication flow rate, and the material thermophysical property data jointly constrain the preheating output energy, preventing continuous melting or through-cracks on the carbide surface caused by preheating. The preheating state is entered into the single-piece process record, so that the preheating parameters of the next carbide tool to be machined of the same specification or a nearby specification can be updated under the constraint of safety boundaries.

[0085] Example 3: This example is applicable to batch grinding of TCT solid head carbide cutting tools of the same or adjacent specifications with large length-to-diameter ratio.

[0086] During batch grinding, the working surface of the diamond wheel will wear down, and the edge radius, end face flatness, and outer diameter of the diamond wheel may gradually change. If the control system still executes the zoned linkage grinding control data according to the nominal profile of the diamond wheel, the groove depth, cutting edge profile, and clearance angle profile will drift piece by piece. In order to distinguish the diamond wheel profile deviation, the tool deflection error of the carbide tool to be machined, and the thermal expansion and contraction error, this embodiment sets up a line laser profile scanning unit.

[0087] The line laser profile scanning unit is positioned to avoid interfering with the diamond wheel grinding process. It scans the working surface of the diamond wheel between adjacent grinding operations, when the diamond wheel is retracted, or after a single piece is machined. During scanning, the diamond wheel rotates at a low speed or is scanned at a fixed angle. The line laser profile scanning unit acquires the profile point cloud data of the diamond wheel's working surface. The control system registers the profile point cloud data with the nominal profile data of the diamond wheel. The registration method includes reference circle fitting, profile feature point matching, or iterative nearest-point registration. After registration, the control system obtains the diamond wheel profile deviation data. This data includes changes in the diamond wheel's outer diameter, edge fillet radius, end face runout, suspected local notches, and changes in the effective grinding width.

[0088] If the diamond wheel profile deviation data is within the compensable range, the control system converts the diamond wheel profile deviation data into a diamond wheel position compensation component in the zoned linkage grinding control data. The diamond wheel position compensation component is stored separately from the feed correction. The diamond wheel position compensation component is used to correct systematic errors caused by changes in the diamond wheel's geometry, while the feed correction is used to correct dynamic bending and thermal expansion / contraction of the overhang machining section during grinding. If the diamond wheel profile deviation data exceeds the compensable range, the control system pauses processing and prompts for diamond wheel dressing. After diamond wheel dressing is completed, the line laser profile scanning unit rescans the diamond wheel's working surface. Once the diamond wheel profile deviation data returns to the compensable or nominal range, the control system resumes processing.

[0089] For example, the compensable range for diamond wheel outer diameter deviation is -10 μm to +10 μm, the compensable range for diamond wheel edge radius variation is 0 μm to 8 μm, and the compensable range for diamond wheel end face runout is 0 μm to 5 μm. If the diamond wheel outer diameter deviation exceeds the compensable range, the control system will not execute the diamond wheel position compensation component, but will instead prompt for diamond wheel dressing. If the diamond wheel edge radius variation is within the compensable range, the control system will convert the diamond wheel edge radius variation into groove bottom contour compensation data and write it into the zoned linkage grinding control data.

[0090] In batch processing, the quality feedback update unit generates a single-piece process record for each carbide tool to be processed. The single-piece process record includes the specifications of the carbide tool, material batch, clamping record, non-contact radial support boundary, tail shank axial buffer boundary, chip removal cooling branch spray record, low-temperature micro-lubrication branch spray record, zoned linkage grinding control data, bending compensation, thermal expansion compensation, feed correction, workpiece spindle speed correction, diamond wheel profile deviation data, dimensional deviation data, and surface topography data. If sensor failure, nozzle blockage, abnormal air supply, diamond wheel profile exceeding limits, manual pause, or safety interlock triggering occurs during processing, the single-piece process record is marked as an abnormal sample.

[0091] The quality feedback update unit groups updatable samples. Grouping criteria include outer diameter, overhang length, groove depth, material thermophysical properties, and local bending support status. Adjacent sizes of carbide cutting tools can be merged for analysis, but the variations in outer diameter, overhang length, and groove depth must be within preset ranges, and the local bending support status must be convertible using the same calibration table or model. If the differences in local bending support status between adjacent sizes of carbide cutting tools exceed preset ranges, the quality feedback update unit will not merge them to avoid writing inapplicable parameters into the parameter candidate area.

[0092] For updatable samples within the same group, the quality feedback update unit performs density clustering. The input to density clustering is not a single-dimensional result, but rather multi-dimensional data including trajectory parameters, compensation parameters, support boundaries, cooling spray, and surface morphology. After clustering, the quality feedback update unit extracts cluster core samples. The parameter combinations corresponding to the cluster core samples are considered to have stable machining results under similar operating conditions. The quality feedback update unit extracts the radial penetration depth boundary, axial feed rate boundary, bending compensation boundary, thermal expansion compensation boundary, workpiece spindle speed correction boundary, chip removal cooling flow rate boundary, and low-temperature micro-lubrication spray boundary from the cluster core samples. The extracted results are written into the parameter candidate region.

[0093] The parameter candidate region is constrained by safety boundaries. These safety boundaries include the allowable speed of the machine tool motion axis, the allowable acceleration of the machine tool motion axis, the allowable range of diamond wheel linear velocity, the minimum radial clearance of the non-contact radial guide unit, the maximum axial micro-displacement of the magnetorheological axial buffer unit, the safe flow rate of the cryogenic gas-liquid medium, the maximum lateral jet component of the chip removal cooling branch, the upper limit of material heat load, and process card limitations. If a feed rate corresponding to a cluster core sample exceeds the safety boundary, the quality feedback update unit will not write that feed rate into the production boundary. If a compensation amount exceeds the compensation parameter boundary, the quality feedback update unit will mark the single-piece process record as an over-compensated sample and prompt for checking the non-contact radial guide unit, magnetorheological axial buffer unit, or diamond wheel profile status.

[0094] In mass production, the quality feedback update unit is also used to identify error sources. If the groove depth of multiple consecutive carbide cutting tools is consistently shallow along the entire axial direction, and the diamond wheel profile deviation data shows that the outer diameter of the diamond wheel is decreasing, the control system prioritizes updating the diamond wheel position compensation component or prompts for diamond wheel dressing. If the free end outer diameter of multiple consecutive carbide cutting tools is too large, and the bending compensation is close to the upper limit, the control system prioritizes reducing the radial penetration depth of the grinding operation area corresponding to the free end, and prompts for checking the guide air pressure and radial clearance of the non-contact radial guide unit. If the surface morphology data of multiple consecutive carbide cutting tools shows secondary scratches from grinding chips, the control system prioritizes checking the nozzle direction and grinding chip discharge status of the chip removal cooling branch. If the surface morphology data of multiple consecutive carbide cutting tools shows periodic vibration marks, and the workpiece spindle vibration data has a stable energy concentration frequency band, the control system prioritizes expanding the workpiece spindle speed correction boundary or adjusting the diamond wheel linear speed. If multiple carbide cutting tools to be machined show signs of suspected hot cracking, the control system will prioritize reducing the output energy of laser-assisted preheating, increasing the cooling capacity of the low-temperature micro-lubrication branch, or reducing the radial depth of cut in the corresponding grinding operation area.

[0095] In this embodiment, diamond wheel profile compensation, thermal compensation, and quality feedback updates are processed separately within the same data chain. Diamond wheel profile deviation data is not mistaken for bending errors in the carbide cutting tool being machined; bending compensation is not mistakenly used to correct diamond wheel wear; and thermal expansion compensation is not mistakenly used to correct nozzle clogging. This differentiated processing improves the reliability of parameter updates during batch processing.

[0096] Example 4: This example discloses a grinding system for TCT solid-head carbide cutting tools with a large length-to-diameter ratio. The system includes a double-boundary flexible support mechanism, a graded cooling and lubrication module, a trajectory generation unit, a force and heat compensation control unit, a quality feedback update unit, and a machine tool CNC execution unit. Each unit can be integrated into the same CNC tool grinder, or it can be implemented collaboratively by a machine tool controller, an edge computing controller, a sensor controller, and a process database.

[0097] The dual-boundary flexible support mechanism includes a base clamping unit, a magnetorheological axial buffer unit, and a non-contact radial guide unit. The base clamping unit clamps the tailstock. The magnetorheological axial buffer unit receives the tailstock axial preload, the rate of change of grinding normal force, and the rate of change of radial displacement, and outputs the excitation status. The non-contact radial guide unit receives the guide air pressure, zoned throttling status, and exhaust status, and outputs the non-contact radial support boundary. The dual-boundary flexible support mechanism also includes an air supply filter unit, a gas drying unit, a gas pressure closed-loop valve assembly, an excitation current driver, and a temperature monitoring unit. The air supply filter unit and the gas drying unit reduce particles and moisture within the gas static pressure guide sleeve. The gas pressure closed-loop valve assembly adjusts the guide air pressure in each air supply zone. The excitation current driver adjusts the excitation coil current. The temperature monitoring unit monitors the temperature drift of the magnetorheological axial buffer unit and the non-contact radial guide unit.

[0098] The graded cooling and lubrication module includes a chip removal cooling branch, a low-temperature micro-lubrication branch, a nozzle positioning mechanism, and a chip discharge status detection unit. The chip removal cooling branch includes a water-based grinding fluid pump, a flow control valve, nozzles, and a reflux filter structure. The low-temperature micro-lubrication branch includes a low-temperature gas-liquid medium supply source, a micro-lubrication supplier, a layered solid lubricant particle carrier liquid supplier, a particle conveying branch, a short mixing chamber, and nozzles. The particle conveying branch delivers layered solid lubricant particles into the short mixing chamber. The nozzle positioning mechanism adjusts the spray angle of the chip removal cooling branch and the low-temperature micro-lubrication branch. The chip discharge status detection unit outputs the chip discharge status to the low-temperature micro-lubrication branch and the chip removal cooling branch, allowing for closed-loop adjustment of the spray angle and spray flow rate.

[0099] The trajectory generation unit is implemented by the process processor in the machine tool CNC system or by an independent edge computing controller. The trajectory generation unit receives the design file of the carbide tool to be machined, material thermophysical property data, non-contact radial support boundaries, tail shank axial buffer boundaries, and trajectory parameter boundaries in the parameter candidate area. The trajectory generation unit outputs zoned linkage grinding control data. The trajectory generation unit also receives diamond wheel profile deviation data and generates diamond wheel position compensation components when the diamond wheel profile deviation data is within a compensable range.

[0100] The force-thermal compensation control unit receives radial displacement, grinding normal force, grinding contact temperature, cooling jet parameters, and workpiece spindle vibration data. The control unit includes a data acquisition interface, a baseline correction program, a time alignment program, a bending compensation generation program, a thermal expansion compensation generation program, a consistency verification program, a workpiece spindle speed correction program, and an anomaly marking program. The data acquisition interface inputs sensor data at different sampling frequencies into the controller. The baseline correction program performs guide clearance baseline correction, no-load drift correction, jet obstruction compensation, and workpiece spindle idle frequency band elimination. The time alignment program aligns the corrected data to the same time reference. The bending compensation generation program outputs the bending compensation amount. The thermal expansion compensation generation program outputs the thermal expansion compensation amount based on grinding contact temperature, cooling jet parameters, and material thermophysical property data. The consistency verification program outputs the feed correction amount or a marker for the interval to be verified. The workpiece spindle speed correction program outputs the workpiece spindle speed correction amount based on the current chatter frequency band, the current workpiece spindle speed, the diamond wheel surface characteristic passing frequency, the allowable range of workpiece spindle speed, and the allowable range of diamond wheel linear velocity. The anomaly marking program writes sensor anomalies, compensation exceeding limits, or spraying anomalies into the individual process record.

[0101] The quality feedback update unit receives dimensional deviation data, surface topography data, support boundary data, cooling jet data, grinding process data, and diamond wheel profile deviation data. The quality feedback update unit includes a single-piece process record generation program, a quality grading program, an anomaly sample rejection program, a density clustering program, a safety boundary constraint program, and a parameter candidate area writing program. The single-piece process record generation program generates a complete machining record for each carbide tool to be machined. The quality grading program determines whether the single-piece process record is qualified. The anomaly sample rejection program rejects abnormal records caused by sensor failure, nozzle blockage, diamond wheel profile exceeding limits, or human intervention. The density clustering program extracts cluster core samples from updatable samples. The safety boundary constraint program ensures that the trajectory parameters and compensation parameters written to the parameter candidate area do not exceed the limitations of the equipment, material, and process card. The parameter candidate area writing program provides the updated trajectory parameter boundaries and compensation parameter boundaries for use by the next carbide tool of the same specification or a nearby carbide tool to be machined.

[0102] In some embodiments, the non-contact radial guide unit is replaced by a gas hydrostatic guide sleeve with a pressure-vacuum composite air float support. The pressure-vacuum composite air float support has an air supply zone and a negative pressure exhaust zone on the inner circumferential surface of the guide sleeve. The air supply zone provides gas film support, and the negative pressure exhaust zone improves the positional stability of the gas film. The pressure-vacuum composite air float support is suitable for machining carbide cutting tools with smaller outer diameters and more sensitive radial clearances.

[0103] In some implementations, the magnetorheological axial buffer unit replaces the magnetorheological medium shear cavity with a magnetorheological elastomer buffer structure. The magnetorheological elastomer buffer structure alters its equivalent stiffness and damping under an applied magnetic field, and its sealing requirements are lower than those of the magnetorheological medium shear cavity. The magnetorheological elastomer buffer structure is suitable for low-maintenance retrofitting of existing tool grinders.

[0104] In some implementations, radial displacement is obtained by inversion of film pressure and air supply flow rate, without directly using a displacement sensor. When using film pressure and air supply flow rate inversion, the control system needs to establish a calibration relationship between pressure, flow rate, and clearance using a standard bar before grinding. This method reduces sensor exposure to grinding debris and cooling spray.

[0105] In some implementations, the bending compensation and thermal expansion compensation are generated by a lookup table model, a rule-based model, a regression model, a neural network model, or a combination of these models. Regardless of the model used, the input should include data corresponding to the physical state of the grinding process, and the output should be converted into an executable feed correction or a marked interval for verification.

[0106] It is important to note that, in this specification, TCT solid head carbide cutting tools refer to rotary cutting tools whose cutting head is formed of carbide and whose main grinding section is a solid carbide head. These include solid carbide end mills, solid head carbide drilling tools, and solid head carbide grooving tools. The scope of protection for this invention extends to grinding methods, systems for performing grinding methods, and corresponding computer-readable storage media, and does not solely protect the structure of the finished carbide cutting tool itself.

[0107] A large length-to-diameter ratio refers to a ratio of the overhang length to the outer diameter of the carbide cutting tool to be machined, which is not less than 10. The overhang length is the axial length of the carbide cutting tool from the effective clamping end face to the free end of the groove area to be ground. The outer diameter is the unmachined outer diameter of the carbide cutting tool before it enters the grinding process.

[0108] 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.

[0109] 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 grinding method for a large aspect ratio TCT solid-head carbide cutting tool, characterized in that, include: The tail shank of the carbide tool to be machined is clamped in the base clamping unit, and a non-contact radial support boundary and a tail shank axial buffer boundary are established for the overhanging machining section of the carbide tool to be machined. Before and during the grinding of the overhanging section by the diamond grinding wheel, the grinding contact area is cooled, lubricated and chip removed by the cooling and lubricating medium, and the spraying state of the cooling and lubricating medium is adjusted according to the chip removal state. The local bending support state is determined based on the axial overhang position of the carbide tool to be machined, the target groove geometry, the non-contact radial support boundary, and the tail shank axial buffer boundary, and the partition linkage grinding control data is generated based on the local bending support state. During the grinding process, the grinding process status data of the overhanging section is collected. Based on the grinding process status data, the bending compensation amount, thermal expansion compensation amount and workpiece spindle speed correction amount are generated. The bending compensation amount and thermal expansion compensation amount are merged to form the feed correction amount, which is then superimposed on the zone linkage grinding control data. After the grinding of a single carbide tool is completed, the dimensional deviation data and surface morphology data of the machined surface are obtained. The dimensional deviation data, surface morphology data, support boundary data, cooling spray data and grinding process data are combined into a single-piece process record. Based on the single-piece process record, the trajectory parameter boundary and compensation parameter boundary of the next carbide tool of the same specification or a carbide tool of a nearby specification are updated.

2. The grinding method for a large aspect ratio TCT solid-head carbide cutting tool according to claim 1, characterized in that, The ratio of the overhang length to the outer diameter of the carbide tool to be machined is not less than 10; the overhang machining section includes the groove area to be ground and the unground support area, the non-contact radial support boundary acts on the unground support area, and the diamond grinding wheel acts on the groove area to be ground.

3. The grinding method for a large aspect ratio TCT solid-head carbide cutting tool according to claim 1, characterized in that, Establishing the non-contact radial support boundary and the tailstock axial buffer boundary includes: The overhanging section passes through the non-contact radial guide unit. The air supply state of the non-contact radial guide unit is adjusted based on the radial clearance measured before grinding. The non-contact radial support boundary acting on the overhanging section is determined by the radial clearance and the air supply state. The excitation state of the magnetorheological axial buffer unit is adjusted based on the axial preload of the tailstock, and the axial buffer boundary of the tailstock is determined by the excitation state.

4. The grinding method for a large aspect ratio TCT solid-head carbide cutting tool according to claim 3, characterized in that, The non-contact radial guide unit includes a gas static pressure guide sleeve with an open guide window, which avoids the diamond grinding wheel and the grinding contact area; the gas supply state includes guide air pressure, zoned throttling state and exhaust state, and the non-contact radial support boundary is jointly determined by the radial clearance, guide air pressure and zoned throttling state.

5. The grinding method for a large aspect ratio TCT integral head carbide cutting tool according to claim 3, characterized in that, The magnetorheological axial buffer unit includes an annular shearing cavity connected in series with the base clamping unit, an excitation coil disposed outside the annular shearing cavity, and a magnetorheological medium disposed inside the annular shearing cavity. The excitation state is adjusted according to the axial preload of the tailstock, the rate of change of the grinding normal force, and the rate of change of the radial displacement, so that the axial buffer boundary of the tailstock is limited to a preset axial micro-displacement range.

6. The grinding method for a large aspect ratio TCT solid-head carbide cutting tool according to claim 1, characterized in that, The cooling and lubricating media include water-based grinding fluid sprayed by the chip removal cooling branch and atomized lubricating flow sprayed by the low-temperature micro-lubrication branch; the atomized lubricating flow contains low-temperature gas-liquid medium and sheet-like solid lubricating particles; The state of grinding debris discharge is obtained by optical turbidity detection, image detection or acoustic emission detection; when the state of grinding debris discharge indicates an increase in grinding debris retention, the flow rate of water-based grinding fluid is increased or the direction of water-based grinding fluid injection is changed, and the lateral injection component generated by the low-temperature micro-lubrication branch on the overhanging machining section is reduced.

7. The grinding method for a large aspect ratio TCT solid-head carbide cutting tool according to claim 1, characterized in that, The generation of zoned linkage grinding control data includes: Establish an axial position sequence along the central axis of the carbide cutting tool to be machined; The local bending support state is determined based on the distance from each axial position to the base clamping unit in the axial position sequence, the non-contact radial support boundary, the tail shank axial buffer boundary, and the target groove geometry. Based on the local bending support state, the continuous grinding trajectory is decomposed into multiple grinding operation intervals with overlapping transition zones, and radial depth of cut, axial feed rate, axial movement data of the carbide tool to be processed, and rotation angle data of the carbide tool to be processed are assigned to each grinding operation interval. The radial depth of cut and the axial feed rate of each grinding operation zone are determined based on the local bending support state. The radial depth of cut and the axial feed rate are positively correlated with the local bending support state and are smoothly connected in the overlapping transition zone of adjacent grinding operation zones.

8. The grinding method for a large aspect ratio TCT solid-head carbide cutting tool according to claim 1, characterized in that, The grinding process status data includes radial displacement, grinding normal force, grinding contact temperature, cooling spray parameters, and workpiece spindle vibration data. Before generating bending compensation, thermal expansion compensation, and workpiece spindle speed correction, guide clearance baseline correction is performed on the radial displacement, no-load drift correction is performed on the grinding normal force, spray shielding compensation is performed on the grinding contact temperature, and workpiece spindle vibration data is processed by eliminating the workpiece spindle idle frequency band. The corrected grinding process status data are then aligned with the same time reference.

9. The grinding method for a large aspect ratio TCT integral head carbide cutting tool according to claim 8, characterized in that, The bending compensation is obtained based on radial displacement and grinding normal force; the thermal expansion compensation is obtained based on grinding contact temperature, cooling spray parameters and material thermophysical data; the cooling spray parameters include chip removal cooling branch flow rate, chip removal cooling branch spray angle, low temperature micro-lubrication branch spray flow rate and low temperature micro-lubrication branch spray angle.

10. The grinding method for a large aspect ratio TCT solid-head carbide cutting tool according to claim 1, characterized in that, The process of combining bending compensation and thermal expansion compensation to form a feed correction includes: determining the compensation direction of bending compensation and thermal expansion compensation in the diamond wheel feed direction; when the compensation directions are consistent, generating a feed correction according to a preset safety ratio; when the compensation directions are opposite and the difference exceeds a preset difference threshold, reducing the radial depth of cut in the current grinding operation range and marking the current grinding operation range as a range to be reviewed.

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