Five-axis machining milling force coefficient identification method and system and electronic equipment

Abstract

The invention provides a five-axis machining milling force coefficient identification method and system and electronic equipment, and relates to the technical field of computer-aided manufacturing, and the method comprises the steps: building an infinitesimal cutting force model according to an instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of a blade infinitesimal, and the relationship between the undeformed cutting width of the blade infinitesimal and the infinitesimal cutting force; superposing the infinitesimal cutting forces of all cutting edge infinitesimal elements participating in cutting to obtain an instantaneous cutting resultant force; combining the infinitesimal cutting force model and the instantaneous cutting resultant force to establish a first relation model; milling force standard data in the five-axis milling process are obtained; in combination with the milling force standard data and the first relation model, calibrating the instantaneous cutting force coefficient; and obtaining a target milling force coefficient in combination with the average undeformed cutting thickness of the blade micro-element and the calibrated instantaneous cutting force coefficient. The five-axis milling force identification method solves the problem that an existing five-axis milling force identification method is limited in application scene.

Description

Technical Field

[0001] The present invention relates to the technical field of computer-aided manufacturing, and in particular to a five-axis machining milling force coefficient identification method, system and electronic equipment. Background Art

[0002] Five-axis milling is widely used in aerospace, automobile manufacturing, mold engraving, energy equipment and other industries. Compared with three-axis machining, five-axis machining adds two rotational degrees of freedom, expands the tool's posture selection relative to the workpiece, and thus realizes the precision manufacturing of complex surfaces and structural parts, such as gas turbine blades, aircraft engine blades, engine turbines, etc. Milling force is an important factor that determines the machining performance of parts, such as machine tool vibration, machining stability, tool wear, tool breakage, machining surface morphology, machining accuracy, etc. Accurate modeling, simulation and monitoring of five-axis milling force is the basic technology for high-performance milling of complex parts.

[0003] In the cutting process of complex and difficult-to-machine parts such as nickel-based high-temperature alloy blades, the contact area between the tool and the workpiece changes with the change of the tool position position, and the wear state of the tool changes significantly during the material removal process, which brings great challenges to the modeling of the milling process and the accurate prediction of the milling force. In recent years, a method for instantaneous milling force coefficient identification has been proposed, and the milling force is mapped based on the spindle current and drive shaft current during the machining process to achieve online monitoring of the milling force coefficient and tool wear.

[0004] However, the above milling force coefficient identification method has limited application scenarios and cannot be applied to five-axis machining processes. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a five-axis machining milling force coefficient identification method, system and electronic equipment, which solves the problem of limited applicable scenarios of the existing five-axis milling force identification method.

[0006] At least one embodiment of the present invention provides a method for identifying a five-axis machining milling force coefficient, comprising:

[0007] According to the relationship between the instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of the blade microelement, the undeformed cutting width of the blade microelement and the microelement cutting force, a microelement cutting force model is established;

[0008] The micro-element cutting forces of all blade micro-elements involved in cutting are superimposed to obtain the instantaneous cutting force;

[0009] Combining the micro-element cutting force model and the instantaneous cutting force, establishing a first relationship model between the instantaneous cutting force and the instantaneous cutting force coefficient;

[0010] Acquire standard milling force data during five-axis milling, wherein the standard milling force data is characterized by instantaneous cutting force of the spindle at multiple rotation angle phases;

[0011] Calibrate the instantaneous cutting force coefficient by combining the milling force standard data and the first relationship model;

[0012] According to the instantaneous undeformed cutting thickness of the blade micro-element, the average undeformed cutting thickness of the blade micro-element is obtained;

[0013] The target milling force coefficient is obtained by combining the average undeformed cutting thickness of the blade microelement and the calibrated instantaneous cutting force coefficient.

[0014] The technical solution disclosed in the present invention has at least the following beneficial effects:

[0015] The present invention establishes a microelement cutting force model by utilizing the relationship between the instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of the blade microelement, the undeformed cutting width of the blade microelement and the microelement cutting force, and superimposes the microelement cutting forces of all blade microelement involved in cutting to obtain an instantaneous cutting resultant force, and combines the microelement cutting force model and the instantaneous cutting resultant force to establish a first relationship model between the instantaneous cutting resultant force and the instantaneous cutting force coefficient, and then obtains the standard milling force data in the five-axis milling process, and combines the standard milling force data and the first relationship model to calibrate the instantaneous cutting force coefficient; obtains the average undeformed cutting thickness of the blade microelement according to the instantaneous undeformed cutting thickness of the blade microelement; and finally, combines the average undeformed cutting thickness of the blade microelement and the calibrated instantaneous cutting force coefficient to obtain the target milling force coefficient;

[0016] This method only needs to obtain the standard milling force data of one cutter tooth rotation cycle during the five-axis machining process to complete the rapid calibration of the relevant instantaneous milling force coefficient and finally obtain the target milling force coefficient. Compared with the existing technology, this method is more adaptable to a wider range of scenarios and more convenient.

[0017] In one embodiment of a five-axis machining milling force coefficient identification method provided by the present invention, obtaining standard milling force data during the five-axis milling process includes:

[0018] The original data of milling force in the five-axis milling process is obtained. The original data of milling force is subjected to polynomial smoothing filtering and tooth angle phase averaging filtering respectively to obtain the standard data of milling force.

[0019] The technical solution disclosed in the present invention has at least the following beneficial effects:

[0020] Through the above two filterings, the high-order vibration signals generated during the machining process and the cutting force signal differences of different teeth during one rotation of the tool can be filtered out respectively, so that the milling force data of different teeth are consistent and the influence of tool axis runout on the milling force is eliminated.

[0021] In one embodiment of a five-axis machining milling force coefficient identification method provided by the present invention, the specific formula of the micro-element cutting force model is as follows:

[0022] dF q,j (z) = K q hdb(z);

[0023] Among them, dF q,j (z) is expressed as micro-element cutting force, K q are the instantaneous cutting force coefficients in radial, tangential and axial directions, h is the instantaneous undeformed cutting thickness of the blade element, and db(z) is the undeformed cutting width of the blade element.

[0024] In one embodiment of a five-axis machining force coefficient identification method provided by the present invention, the micro-element cutting forces of all blade micro-elements involved in cutting are superimposed to obtain an instantaneous cutting force, including:

[0025] Obtain the lower boundary position and the upper boundary position of the blade element along the main axis direction;

[0026] The calculation formula of the instantaneous cutting force is:

[0027]

[0028] in, It is expressed as the main axis rotation phase The instantaneous cutting force at that time, N is the number of tool teeth, Z1 is the lower boundary position, Z2 is the upper boundary position, and A is the rotation transformation matrix from the micro-element cutting force to the workpiece coordinate system.

[0029] In one embodiment of a five-axis machining force coefficient identification method provided by the present invention, the formula for obtaining the undeformed cutting width of the blade microelement is as follows:

[0030]

[0031] Among them, κ is the radial position angle, and dz is the discrete element in the main axis direction of the blade.

[0032] In one embodiment of a five-axis machining milling force coefficient identification method provided by the present invention, combining the micro-element cutting force model and the instantaneous cutting force, a first relationship model between the instantaneous cutting force and the instantaneous cutting force coefficient is established, including:

[0033] Combining the micro-element cutting force model and the instantaneous cutting force, establishing a prediction model of the instantaneous cutting force;

[0034] A first relationship model when the number of tool teeth is 1 is obtained according to the prediction model.

[0035] By transforming the prediction model into a first relationship model in which the number of tool teeth is 1, the subsequent calculation process can be greatly simplified.

[0036] In one embodiment of a five-axis machining milling force coefficient identification method provided by the present invention, the specific formula of the first relationship model is as follows:

[0037]

[0038] Among them, F is the feed rate, unit is mm / min, n is the tool rotation speed, unit is r / min, θ L is the forward tilt angle, K r is the average value of radial cutting force coefficient, K t is the average value of the tangential cutting force coefficient, K a is the average value of the cutting force coefficient in the spindle direction, and P κ is the intermediate parameter of the prediction model.

[0039] In one embodiment of a five-axis machining force coefficient identification method provided by the present invention, the calculation formula of the instantaneous undeformed cutting thickness of the blade microelement is:

[0040]

[0041] The calculation formula of the average undeformed cutting thickness of the blade microelement is:

[0042]

[0043] Among them, the Expressed as the average undeformed cutting thickness of the cutting edge element.

[0044] At least one embodiment of the present invention further provides a five-axis machining milling force coefficient identification system, comprising:

[0045] A micro-element cutting force model building module is used to build a micro-element cutting force model according to the relationship between the instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of the blade micro-element, the undeformed cutting width of the blade micro-element and the micro-element cutting force;

[0046] The instantaneous cutting force calculation module adds up the micro-element cutting forces of all blade micro-elements involved in cutting to obtain the instantaneous cutting force;

[0047] A calibration model building module is used to build a first relationship model between the instantaneous cutting force and the instantaneous cutting force coefficient by combining the micro-element cutting force model and the instantaneous cutting force.

[0048] A data acquisition module, which acquires standard data of milling force during five-axis milling, wherein the standard data of milling force is characterized by instantaneous cutting force of the spindle at multiple rotation angle phases;

[0049] A calibration module, combining the milling force standard data and the first relationship model to calibrate the instantaneous cutting force coefficient;

[0050] An average undeformed cutting thickness calculation module is used to obtain the average undeformed cutting thickness of the blade element according to the instantaneous undeformed cutting thickness of the blade element;

[0051] The target milling force coefficient determination module combines the average undeformed cutting thickness of the blade microelement and the calibrated instantaneous cutting force coefficient to obtain the target milling force coefficient.

[0052] The present invention also provides an electronic device, comprising a memory, a processor, and a program stored in the memory and running on the processor, wherein when the processor executes the program, a method for identifying milling force coefficients of five-axis machining as described above is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flow chart of a method for identifying milling force coefficients in five-axis machining according to the present invention;

[0054] Figure 2 It is a principle diagram of polynomial smoothing filtering of the present invention;

[0055] Figure 3 This is the original data of milling force without filtering by the inter-tooth angle phase averaging method;

[0056] Figure 4 This is the original data of milling force after filtering by the inter-tooth angle phase averaging method;

[0057] Figure 5 is the relationship diagram between the instantaneous milling force coefficient and the instantaneous undeformed cutting thickness;

[0058] Figure 6 The present invention is a flowchart of a five-axis machining milling force coefficient identification system. DETAILED DESCRIPTION

[0059] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0060] Furthermore, those skilled in the art may combine and associate different embodiments or examples and features of different embodiments or examples described in this specification without mutual contradiction.

[0061] Considering the increased rotational freedom factor of five-axis machining, the research on milling force in five-axis machining focuses on the instantaneous undeformed cutting thickness model and the tool-workpiece cutting area model. The prior art proposes a parameterized instantaneous undeformed cutting thickness model and provides a calculation method for the instantaneous undeformed cutting thickness directly related to the rake angle and roll angle of five-axis machining. The prior art establishes a five-axis machining tool-workpiece cutting contact area boundary line model related to the rake angle and roll angle, which consists of three types of feature lines, intersection lines and projection lines.

[0062] Whether based on a mechanical force model or a constitutive analytical model, the accurate prediction of milling forces also depends on the accuracy of the milling force coefficient. In addition to being related to tool characteristics and workpiece characteristics, the milling force coefficient is also related to process parameters. Grossi et al. used an instantaneous method to study the dependence of the force coefficient on the spindle speed. This method proposes a nonlinear optimization problem, namely, finding a set of force coefficients and runout parameters to minimize the difference between the model and experimentally measured cutting forces. Rubeo and Schmitz also used the instantaneous method to further study the relationship between the cutting force coefficient and feed rate and cutting width. In general, increasing the feed rate or radial cutting width will lead to a decrease in the cutting force coefficient, while increasing the cutting speed will also reduce the cutting force coefficient due to thermal softening of the material.

[0063] In addition to process dependence, the cutting force coefficient is sensitive to the flank wear of the tool, which increases gradually as the tool wears throughout the machining operation. Ducroux et al. combined the effects of tool wear with the edge force coefficient by introducing an additional wear-related coefficient into the milling force model. Denkena et al. proposed a tool wear index that is formed under the weighted sum of the normalized force coefficients and retains a larger weight for the edge coefficient to emphasize its sensitivity to tool health. Nouri et al. also proposed a customized tool wear index by continuously tracking the force coefficient. This strategy indirectly relates the force coefficient to tool health and provides an alternative to direct monitoring of the tool under optical measurement, overcoming the problem that optical measurement is difficult to achieve online.

[0064] In the cutting process of complex and difficult-to-machine parts such as nickel-based high-temperature alloy blades, the contact area between the tool and the workpiece changes with the change of the tool position position, and the wear state of the tool changes significantly during the material removal process, which brings great challenges to the modeling of the milling process and the accurate prediction of the milling force. In recent years, Liu et al. proposed a method for identifying the instantaneous milling force coefficient, and mapped the milling force based on the spindle current and drive shaft current during the machining process, realizing the online monitoring of the milling force coefficient and tool wear.

[0065] Previous methods for identifying milling force coefficients are mostly limited to cutting under specific conditions and cannot be applied to five-axis machining processes. This paper proposes an instantaneous calibration method for milling force coefficients in five-axis machining, which only requires milling force data of one tooth tool rotation cycle to complete the rapid calibration of the target milling force coefficient.

[0066] The present invention provides a five-axis machining milling force coefficient identification method. Figure 1 As shown, including:

[0067] According to the relationship between the instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of the blade microelement, the undeformed cutting width of the blade microelement and the microelement cutting force, a microelement cutting force model is established;

[0068] The micro-element cutting forces of all blade micro-elements involved in cutting are superimposed to obtain the instantaneous cutting force;

[0069] Combining the micro-element cutting force model and the instantaneous cutting force, establishing a first relationship model between the instantaneous cutting force and the instantaneous cutting force coefficient;

[0070] Acquire standard milling force data during five-axis milling, wherein the standard milling force data is characterized by instantaneous cutting force of the spindle at multiple rotation angle phases;

[0071] Calibrate the instantaneous cutting force coefficient by combining the milling force standard data and the first relationship model;

[0072] According to the instantaneous undeformed cutting thickness of the blade micro-element, the average undeformed cutting thickness of the blade micro-element is obtained;

[0073] The target milling force coefficient is obtained by combining the average undeformed cutting thickness of the blade microelement and the calibrated instantaneous cutting force coefficient.

[0074] The present invention establishes a microelement cutting force model by utilizing the relationship between the instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of the blade microelement, the undeformed cutting width of the blade microelement and the microelement cutting force, and superimposes the microelement cutting forces of all blade microelement involved in cutting to obtain an instantaneous cutting resultant force, and combines the microelement cutting force model and the instantaneous cutting resultant force to establish a first relationship model between the instantaneous cutting resultant force and the instantaneous cutting force coefficient, and then obtains the standard milling force data in the five-axis milling process, and combines the standard milling force data and the first relationship model to calibrate the instantaneous cutting force coefficient; obtains the average undeformed cutting thickness of the blade microelement according to the instantaneous undeformed cutting thickness of the blade microelement; and finally, combines the average undeformed cutting thickness of the blade microelement and the calibrated instantaneous cutting force coefficient to obtain the target milling force coefficient;

[0075] This method only needs to obtain the standard milling force data of one cutter tooth rotation cycle during the five-axis machining process to complete the rapid calibration of the relevant instantaneous milling force coefficient and finally obtain the target milling force coefficient. Compared with the existing technology, this method is more adaptable to a wider range of scenarios and more convenient.

[0076] First, the microelement cutting force model is established according to the relationship between the instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of the blade microelement, the undeformed cutting width of the blade microelement and the microelement cutting force, including:

[0077] Specifically, the specific formula of the micro-element cutting force model is as follows:

[0078] dF q,j (z) = K q hdb(z);

[0079] Among them, dF q,j (z) is expressed as micro-element cutting force, K q are the instantaneous cutting force coefficients in radial, tangential and axial directions, h is the instantaneous undeformed cutting thickness of the blade element, and db(z) is the undeformed cutting width of the blade element.

[0080] The formula for obtaining the undeformed cutting width of the blade element is as follows:

[0081]

[0082] Among them, κ is the radial position angle, and dz is the discrete element in the main axis direction of the blade.

[0083] The calculation formula of the instantaneous undeformed cutting thickness of the blade microelement is:

[0084]

[0085] Where N is the number of tool teeth, F is the feed rate in mm / min, n is the tool rotation speed in r / min, θ L is the forward tilt angle.

[0086] Then, the micro-element cutting forces of all blade micro-elements involved in cutting are superimposed to obtain the instantaneous cutting force, which includes:

[0087] Obtain the lower boundary position and the upper boundary position of the blade element along the main axis direction;

[0088] At a certain moment, the spindle angle is at a specific position. Taking one of the tool edge lines as an example, the corresponding axial position boundaries of the micro-element of the cutting edge are the lower boundary position Z1 and the upper boundary position Z2. The lower boundary position Z1 can be determined by the characteristic line of the tool-workpiece contact area and the spindle angle, and the upper boundary position Z2 can be determined by the intersection line or projection line of the tool-workpiece contact area. The lower boundary position Z1 and the upper boundary position Z2 provide the upper and lower limits of the integral for the subsequent calculation of the instantaneous cutting force.

[0089] The calculation formula of the instantaneous cutting force is:

[0090]

[0091] in, It is expressed as the main axis rotation phase The instantaneous cutting force at that time, N is the number of tool teeth, Z1 is the lower boundary position, Z2 is the upper boundary position, and A is the rotation transformation matrix from the micro-element cutting force to the workpiece coordinate system.

[0092] in,

[0093]

[0094] Subsequently, the microelement cutting force model and the instantaneous cutting force are combined to establish a first relationship model between the instantaneous cutting force and the instantaneous cutting force coefficient, which specifically includes:

[0095] Combining the micro-element cutting force model and the instantaneous cutting force, establishing a prediction model of the instantaneous cutting force;

[0096] The prediction model is:

[0097]

[0098] Among them, the It is expressed as the main axis rotation phase The instantaneous cutting force at the time, F is the feed rate, unit is mm / min, n is the tool rotation speed, unit is r / min, θ L is the forward tilt angle, K ris the average value of radial cutting force coefficient, K t is the average value of the tangential cutting force coefficient, K a is the average value of the cutting force coefficient in the spindle direction, and P κ is the intermediate parameter of the prediction model;

[0099] Through the above equation, it is obvious that when we get K r is the average value of radial cutting force coefficient, K t After the average value of the tangential cutting force coefficient is obtained, the spindle angle phase can be substituted into the formula to predict: The instantaneous cutting force at

[0100] In order to facilitate subsequent calculations, a first relationship model when the number of tool teeth is 1 is obtained according to the prediction model.

[0101] By transforming the prediction model into a first relationship model in which the number of tool teeth is 1, the subsequent calculation process can be greatly simplified.

[0102] The specific formula of the simplified first relationship model is as follows:

[0103]

[0104] For the above intermediate parameters and P κ , which is related to the rotation angle and position of the cutting edge, the position of the cutting area and the instantaneous milling force coefficient.

[0105] Intermediate parameters The calculation formula is:

[0106] in, and κ are the radial and axial position angles of the blade micro-element coordinates, respectively, and dz is the discrete accuracy of the blade in the axial direction of the tool. and Represents the intermediate parameters The components in the (n=x, y, z) direction are shown in Table 1.

[0107] Table 1 The result of partial integration

[0108]

[0109]

[0110] in, for and The average value, It represents the sum of the spindle rotation angle and the tooth angle, m represents the pitch of the constant pitch tool, and r is the fillet radius of the tool. κ is the axial position angle, which is a constant in the side edge part. The side edge of the ordinary end mill κ = π / 2.

[0111] Intermediate parameter P κ The calculation formula is:

[0112] Among them, p κn1 , p κn2 and p κn3 Represent the intermediate parameters P κ The components in the (n=x, y, z) direction are shown in Table 2.

[0113] Table 2P κ The result of partial integration

[0114]

[0115]

[0116] Subsequently, the milling force standard data in the five-axis milling process is obtained, and the milling force standard data is characterized by the instantaneous cutting force of the main axis at multiple rotation angle phases, specifically including:

[0117] The original data of milling force in the five-axis milling process is obtained. The original data of milling force is subjected to polynomial smoothing filtering and tooth angle phase averaging filtering respectively to obtain the standard data of milling force.

[0118] For polynomial smoothing filtering, combined Figure 2 As shown, the specific principles are as follows:

[0119] Assume that the filter window width is 2m+1, where m represents the filter half window width, the polynomial order is k, and F rough is the raw data sequence of milling force obtained by uniform time sampling, B is the polynomial filter matrix, F SG is the milling force data sequence after filtering. The filtering formula is as follows:

[0120] [F SG ] 2m+1 =[B][F rough ] 2m+1

[0121] in,

[0122] [B]=[X]([X] T [X]) -1 [X] T

[0123]

[0124] For a milling cutter with N teeth, due to the influence of the cutter shaft runout, the milling forces generated by different teeth are significantly different. In order to eliminate the influence of this difference on the milling force, the present invention uses the method of taking the average value of the milling forces at different tooth angles. The average value of milling force of different cutter teeth is:

[0125]

[0126] Where N represents the number of milling cutter teeth, i represents the i-th cutter tooth, Indicates the spindle angle phase, Indicates that the i-th tooth is in phase The milling force, Indicates phase The average milling force is also the spindle angle phase The instantaneous cutting force at that time.

[0127] For a tool with two teeth, the raw data of milling force without filtering by the tooth angle phase averaging method is as follows: Figure 3 As shown in the figure, the data after filtering by the tooth angle phase averaging method is as follows Figure 4 This shows that the filtering method can keep the milling force data of different cutter teeth consistent and remove the influence of cutter axis runout on the milling force.

[0128] Through the above two filterings, the high-order vibration signals generated during the machining process and the cutting force signal differences of different teeth during one rotation of the tool can be filtered out respectively, so that the milling force data of different teeth are consistent and the influence of tool axis runout on the milling force is eliminated.

[0129] Subsequently, the instantaneous cutting force coefficient is calibrated by combining the milling force standard data and the first relationship model. Figure 5 As shown:

[0130] Substitute the obtained milling force standard data into the first relationship equation, refer to Figure 5 , a number of corresponding data sets of instantaneous milling force coefficients and instantaneous undeformed cutting thickness can be obtained;

[0131] According to this data set, the relationship curve of the instantaneous milling force coefficient with respect to the instantaneous undeformed cutting thickness can be calibrated, such as Figure 5 K r , K t , K a The three curves represent the average value of the radial cutting force coefficient, the average value of the tangential cutting force coefficient and the average value of the spindle cutting force coefficient, namely the instantaneous milling force coefficient. The calibrated instantaneous milling force coefficients are: [K r (h),K t(h),K a (h)].

[0132] Then, according to the instantaneous undeformed cutting thickness of the blade microelement, the average undeformed cutting thickness of the blade microelement is obtained, which specifically includes:

[0133] The calculation formula of the average undeformed cutting thickness of the blade microelement is:

[0134]

[0135] Among them, the Expressed as the average undeformed cutting thickness of the cutting edge element.

[0136] Finally, the target milling force coefficient is obtained by combining the average undeformed cutting thickness of the blade microelement and the calibrated instantaneous cutting force coefficient, which specifically includes:

[0137] In the five-axis milling process, when a certain blade is cutting in, cutting to cutting out, the average undeformed chip thickness of the micro-element of the cutting blade with different tooth position angles increases from 0 to the maximum and then decreases to 0. The relationship between the target milling force coefficient and the average instantaneous undeformed chip thickness is:

[0138]

[0139] According to the calibrated instantaneous milling force coefficient [K r (h),K t (h),K a (h)], and the target milling force coefficient is obtained

[0140] The five-axis machining cutting force coefficient calibration experiment of Sandvik2S221-1000-150-NG H10F carbide fillet cutter and aluminum alloy 2024-T6 was carried out on the high-speed and high-precision five-axis gantry machining center GMC1600H / 2. The tool parameters are shown in Table 2-1. The raw data signal of the milling force was measured and recorded using a Kistler9257A dynamometer, a Kistler 5070 charge amplifier and a NI data acquisition system, with a sampling frequency of 10kHz.

[0141] Table 2-1 Tool parameters

[0142]

[0143] Table 2-2 Tool axis runout parameters

[0144]

[0145] The rake angle is 10°, the side rake angle is 15°, the spindle speed is 1200 rpm, the feed rate is 50 mm / min, the cutting depth is 1 mm, and the reference Figure 5 As shown in the figure, the calibration result of the target milling force coefficient is:

[0146]

[0147] The present invention also provides a five-axis machining milling force coefficient identification system. Figure 6 As shown, including:

[0148] A micro-element cutting force model building module is used to build a micro-element cutting force model according to the relationship between the instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of the blade micro-element, the undeformed cutting width of the blade micro-element and the micro-element cutting force;

[0149] The instantaneous cutting force calculation module adds up the micro-element cutting forces of all blade micro-elements involved in cutting to obtain the instantaneous cutting force;

[0150] A calibration model building module is used to build a first relationship model between the instantaneous cutting force and the instantaneous cutting force coefficient by combining the micro-element cutting force model and the instantaneous cutting force.

[0151] A data acquisition module, which acquires standard data of milling force during five-axis milling, wherein the standard data of milling force is characterized by instantaneous cutting force of the spindle at multiple rotation angle phases;

[0152] A calibration module, combining the milling force standard data and the first relationship model to calibrate the instantaneous cutting force coefficient;

[0153] An average undeformed cutting thickness calculation module is used to obtain the average undeformed cutting thickness of the blade element according to the instantaneous undeformed cutting thickness of the blade element;

[0154] The target milling force coefficient determination module combines the average undeformed cutting thickness of the blade microelement and the calibrated instantaneous cutting force coefficient to obtain the target milling force coefficient.

[0155] Furthermore, the data acquisition module specifically includes:

[0156] The original data of milling force in the five-axis milling process is obtained. The original data of milling force is subjected to polynomial smoothing filtering and tooth angle phase averaging filtering respectively to obtain the standard data of milling force.

[0157] Furthermore, the specific formula of the micro-element cutting force model in the micro-element cutting force model building module is as follows:

[0158] dF q,j (z) = K qhdb(z);

[0159] Among them, dF q,j (z) is expressed as micro-element cutting force, K q are the instantaneous cutting force coefficients in radial, tangential and axial directions, h is the instantaneous undeformed cutting thickness of the blade element, and db(z) is the undeformed cutting width of the blade element.

[0160] Furthermore, the instantaneous cutting force calculation module specifically includes:

[0161] Obtain the lower boundary position and the upper boundary position of the blade element along the main axis direction;

[0162] The calculation formula of the instantaneous cutting force is:

[0163]

[0164] in, It is expressed as the main axis rotation phase The instantaneous cutting force at that time, N is the number of tool teeth, Z1 is the lower boundary position, Z2 is the upper boundary position, and A is the rotation transformation matrix from the micro-element cutting force to the workpiece coordinate system.

[0165] Furthermore, the formula for obtaining the undeformed cutting width of the blade element is as follows:

[0166]

[0167] Among them, κ is the radial position angle, and dz is the discrete element in the main axis direction of the blade.

[0168] Furthermore, the calibration model building module in the micro-element cutting force model building module specifically includes:

[0169] Combining the micro-element cutting force model and the instantaneous cutting force, establishing a prediction model of the instantaneous cutting force;

[0170] A first relationship model when the number of tool teeth is 1 is obtained according to the prediction model.

[0171] Furthermore, the specific formula of the first relationship model in the calibration model building module is as follows:

[0172]

[0173] Among them, F is the feed rate, unit is mm / min, n is the tool rotation speed, unit is r / min, θ L is the forward tilt angle, K r is the average value of radial cutting force coefficient, K t is the average value of the tangential cutting force coefficient, K ais the average value of the cutting force coefficient in the spindle direction, and P κ is the intermediate parameter of the prediction model.

[0174] Furthermore, the calculation formula of the instantaneous undeformed cutting thickness of the blade element in the average undeformed cutting thickness calculation module is:

[0175]

[0176] The calculation formula of the average undeformed cutting thickness of the blade microelement is:

[0177]

[0178] Among them, the Expressed as the average undeformed cutting thickness of the cutting edge element.

[0179] The present invention also provides an electronic device, comprising a memory, a processor, and a program stored in the memory and running on the processor, wherein when the processor executes the program, a method for identifying milling force coefficients of five-axis machining as described above is implemented.

[0180] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A five-axis machining milling force coefficient identification method, characterized in that: include: According to the relationship between the instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of the blade microelement, the undeformed cutting width of the blade microelement and the microelement cutting force, a microelement cutting force model is established; The micro-element cutting forces of all blade micro-elements involved in cutting are superimposed to obtain the instantaneous cutting force; Combining the micro-element cutting force model and the instantaneous cutting force, establishing a first relationship model between the instantaneous cutting force and the instantaneous cutting force coefficient; Acquire standard milling force data during five-axis milling, wherein the standard milling force data is characterized by instantaneous cutting force of the spindle at multiple rotation angle phases; Calibrate the instantaneous cutting force coefficient by combining the milling force standard data and the first relationship model; According to the instantaneous undeformed cutting thickness of the blade micro-element, the average undeformed cutting thickness of the blade micro-element is obtained; The target milling force coefficient is obtained by combining the average undeformed cutting thickness of the blade microelement and the calibrated instantaneous cutting force coefficient.

2. A five-axis machining force coefficient identification method according to claim 1, characterized in that: Obtain standard milling force data during five-axis milling, including: The original data of milling force in the five-axis milling process is obtained, and the original data of milling force are respectively subjected to polynomial smoothing filtering and inter-tooth angle phase averaging filtering to obtain the standard data of milling force.

3. A five-axis machining force coefficient identification method according to claim 2, characterized in that: The specific formula of the microelement cutting force model is as follows: dF q,j (z)=K q hdb(z); Among them, dF q,j (z) is expressed as micro-element cutting force, K q are the instantaneous cutting force coefficients in radial, tangential and axial directions, h is the instantaneous undeformed cutting thickness of the blade element, and db(z) is the undeformed cutting width of the blade element.

4. A five-axis machining force coefficient identification method according to claim 3, characterized in that: The instantaneous cutting force is obtained by superimposing the micro-element cutting forces of the blade micro-element involved in cutting, including: Obtain the lower boundary position and the upper boundary position of the blade element along the main axis direction; The calculation formula of the instantaneous cutting force is: in, It is expressed as the main axis rotation phase The instantaneous cutting force at that time, N is the number of tool teeth, Z1 is the lower boundary position, Z2 is the upper boundary position, and A is the rotation transformation matrix from the micro-element cutting force to the workpiece coordinate system.

5. A five-axis machining milling force coefficient identification method according to claim 4, characterized in that: The formula for obtaining the undeformed cutting width of the blade element is as follows: Among them, κ is the radial position angle, and dz is the discrete element in the main axis direction of the blade.

6. A five-axis machining force coefficient identification method according to claim 5, characterized in that: Combining the micro-element cutting force model and the instantaneous cutting force, a first relationship model between the instantaneous cutting force and the instantaneous cutting force coefficient is established, including: Combining the micro-element cutting force model and the instantaneous cutting force, establishing a prediction model of the instantaneous cutting force; A first relationship model when the number of tool teeth is 1 is obtained according to the prediction model.

7. A five-axis machining force coefficient identification method according to claim 6, characterized in that: The specific formula of the first relationship model is as follows: Among them, F is the feed rate, unit is mm / min, n is the tool rotation speed, unit is r / min, θ L is the forward tilt angle, K r is the average value of radial cutting force coefficient, K t is the average value of the tangential cutting force coefficient, K a is the average value of the cutting force coefficient in the spindle direction, and P κ is the intermediate parameter of the prediction model.

8. A five-axis machining force coefficient identification method according to claim 7, characterized in that: The calculation formula of the instantaneous undeformed cutting thickness of the blade microelement is: The calculation formula of the average undeformed cutting thickness of the blade microelement is: Among them, the Expressed as the average undeformed cutting thickness of the cutting edge element.

9. A five-axis machining milling force coefficient identification system, characterized in that: include: A micro-element cutting force model building module is used to build a micro-element cutting force model according to the relationship between the instantaneous cutting force coefficient, the instantaneous undeformed cutting thickness of the blade micro-element, the undeformed cutting width of the blade micro-element and the micro-element cutting force; The instantaneous cutting force calculation module adds up the micro-element cutting forces of all blade micro-elements involved in cutting to obtain the instantaneous cutting force; A calibration model building module is used to build a first relationship model between the instantaneous cutting force and the instantaneous cutting force coefficient by combining the micro-element cutting force model and the instantaneous cutting force. A data acquisition module, which acquires standard data of milling force during five-axis milling, wherein the standard data of milling force is characterized by instantaneous cutting force of the spindle at multiple rotation angle phases; A calibration module, combining the milling force standard data and the first relationship model to calibrate the instantaneous cutting force coefficient; An average undeformed cutting thickness calculation module is used to obtain the average undeformed cutting thickness of the blade element according to the instantaneous undeformed cutting thickness of the blade element; The target milling force coefficient determination module combines the average undeformed cutting thickness of the blade microelement and the calibrated instantaneous cutting force coefficient to obtain the target milling force coefficient.

10. An electronic device comprising a memory, a processor, and a program stored in the memory and running on the processor, characterized in that: When the processor executes the program, a five-axis machining milling force coefficient identification method as described in any one of claims 1 to 8 is implemented.

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