Cutting force prediction method for cutting-out process of weak-rigidity cutter

Abstract

The invention particularly relates to a slip line method-based cutting force prediction method for a weak-rigidity cutter in a cutting-out process. Comprising the steps that firstly, a negative shear effect slip line field is drawn, and cutting force generated by the negative shear effect is calculated based on the slip line field theory; then, according to the geometric and kinematic characteristics of the weak-rigidity tool, whether the flank interference phenomenon occurs or not is judged, a calculation method of interference force generated when flank interference occurs is provided, and finally the cutting force prediction method for the cutting-out process of the weak-rigidity tool is formed. According to the method, analytic modeling and theoretical prediction of the cutting force of the weak-rigidity tool are realized for the first time, and the method can be suitable for cutting force prediction in the cutting-out process of the weak-rigidity tool.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical processing, and in particular to a cutting force prediction method for a cutting process of a weak-rigidity tool. Background Art

[0002] As the cutting process nears its end, the shear plane direction undergoes a sudden change, resulting in a negative shear angle and a negative shear effect. This leads to changes in the material forming mechanism and cutting force generation mechanism. Simultaneously, as the cutting force rapidly decreases, the tool quickly rebounds, potentially causing interference between the flank face and the workpiece, introducing interference forces that impact cutting process modeling and cutting force prediction. Existing cutting force prediction methods ignore the negative shear effect and flank interference during the tool's exit phase at the end of the cut, causing the cutting force prediction results to drop to zero instantly, failing to accurately reveal the cutting force generation mechanism during the tool's exit phase. Therefore, a cutting force prediction method specifically for the exit phase of a weakly stiff tool is urgently needed.

[0003] Document 1 “D.-Y.Wen, M.Wan, S.-C.Linghu, W.-H.Zhang, A slip-line field model for independently characterizing shearing and ploughing effects in metalcutting processes, Wear 556-557(2024)205504” discloses a cutting force prediction method based on slip line field theory, which is aimed at conventional cutting processes with positive shear angles. Since the forming mechanism of negative shear effect materials is different from that of conventional cutting processes, this method cannot be applied to negative shear effects. At the same time, this method does not take into account the influence of the back tool interference phenomenon. Therefore, this method cannot be applied to the cutting force prediction of the cutting process of weak stiffness tools.

[0004] The typical characteristics of the above references are that they are unable to achieve the analysis of the generation mechanism of cutting force and theoretical modeling prediction during the cutting process of weak rigidity tools.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0006] In order to overcome the problem that existing methods cannot be applied to theoretical analysis and prediction of cutting force during the cutting-out process of a weak-rigidity tool, the present invention provides a method for predicting cutting force during the cutting-out process of a weak-rigidity tool based on a slip line method.

[0007] Other features and advantages of the present invention will become apparent from the following detailed description, or may be learned in part by practice of the present invention.

[0008] According to a first aspect of the present invention, a method for predicting cutting force during a cutting process of a weak-rigidity tool based on a slip line method is provided, the method comprising:

[0009] Draw the negative shear effect slip line field, and calculate the tangential cutting force F generated by the negative shear surface based on the negative shear effect slip line field t-n and normal cutting force F n-n ;

[0010] Tangential cutting force F generated by negative shear surface t-n Calculate the cutting power P consumed by the negative shear surface n ;

[0011] Tangential cutting force F generated by negative shear surface t-n and normal cutting force F n-n Calculate the friction coefficient μ of the rake face and record the minimum negative shear surface consumption cutting power P that satisfies μ>μ0 n , where μ0 is the friction coefficient between the tool and the chip;

[0012] If P n ≥P c , then calculate the tangential cutting force F at the current moment t and normal cutting force F n Among them, P c The power consumed by the cutting process at the current moment;

[0013] If P n <P c , then calculate the displacement direction κ based on the tool position coordinates at the current moment and the previous moment; if κ>κ0, calculate the tangential cutting force F at the current moment t and normal cutting force F n If κ≤κ0, the tangential cutting force F at the current moment is calculated based on the tangential force and normal force generated by the flank interference. t and normal cutting force F n ; Where κ0 is the tool back angle.

[0014] In some exemplary embodiments, the tangential cutting force F generated by the negative shear surface is calculated based on the negative shear effect slip line field. t-n and normal cutting force F n-n ;include:

[0015] Calculate the shear strain on the negative shear surface;

[0016] Calculate the shear strain rate on the negative shear surface based on shear strain, negative shear angle, cutting speed, and cutting edge radius;

[0017] Calculate the shear stress on the negative shear surface based on the shear strain rate;

[0018] The tangential cutting force F generated by the negative shear surface is calculated based on the shear stress, normal stress, negative shear angle, cutting width, and tool position coordinates on the negative shear surface. t-n and normal cutting force F n-n .

[0019] In some exemplary embodiments, the tangential cutting force F generated by the negative shear surface is calculated based on the shear stress, normal stress, negative shear angle, cutting width, and tool position coordinates on the negative shear surface. t-n and normal cutting force F n-n , using the following formula:

[0020]

[0021] Among them, τ n is the shear stress, σ n is the normal stress, is the negative shear angle, b is the cutting width, (x t ,y t ) is the tool position coordinate at the current moment t.

[0022] In some exemplary embodiments, the tangential cutting force F generated based on the negative shear surface t-n Calculate the cutting power P consumed by the negative shear surface n , using the following formula:

[0023] P n =F t-n v c

[0024] Among them, v c is the cutting speed.

[0025] In some exemplary embodiments, the tangential cutting force F generated based on the negative shear surface t-n and normal cutting force F n-n To calculate the friction coefficient μ of the rake face, use the following formula:

[0026]

[0027] Among them, α e is the equivalent rake angle.

[0028] In some exemplary embodiments, the displacement direction k is calculated based on the tool position coordinates at the current moment and the previous moment using the following formula:

[0029]

[0030] Among them, (x t-dt ,y t-dt ) is the position coordinate at the previous moment t-dt.

[0031] In some exemplary embodiments, the tangential cutting force F at the current moment is calculated based on the tangential force and normal force generated by the flank interference. t and normal cutting force F n ,include:

[0032] Let the tangential force F generated by the flank interference at the current moment be t-i and the normal force F n-i are all equal to 0;

[0033] The position coordinates of the deformed weak-rigidity tool that meets the conditions are sought through numerical methods;

[0034] Calculate the tangential cutting force and normal cutting force at the current moment based on the position coordinates of the weak-rigidity tool after deformation;

[0035] Update the tangential force F generated by the flank interference at the current moment based on the tangential cutting force and normal cutting force at the current moment t-i and the normal force F n-i ;

[0036] The updated tangential force F generated by the flank interference at the current moment t-i and the normal force F n-i Circular solution of tangential cutting force F t and normal cutting force F n Until the difference between the two cutting forces meets the requirements.

[0037] In some exemplary embodiments, the numerical method is used to find the position coordinates of the deformed weak-rigidity tool that meets the conditions, using the following formula:

[0038]

[0039] Among them, μ r is the tool-workpiece friction coefficient, and a is the acceleration of the tool cutting edge.

[0040] In some exemplary embodiments, the acceleration a of the cutting edge of the tool is calculated as follows:

[0041]

[0042] Among them, F t,0 is the tangential cutting force at the previous moment t-dt, F n,0 is the normal cutting force at the previous moment t-dt, r is the tool radius, l is the tool overhang length, ρ is the tool material density, and a is the acceleration of the tool cutting edge.

[0043] According to a second aspect of the present invention, a storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the cutting force prediction method for the weak stiffness tool cutting process based on the slip line method described in the first aspect is implemented.

[0044] According to a third aspect of the present invention, a computer program product is provided, on which a computer program is stored. When the computer program is executed by a processor, the cutting force prediction method for the weak stiffness tool cutting process based on the slip line method described in the first aspect is implemented.

[0045] According to a fourth aspect of the present invention, there is provided an electronic device, comprising:

[0046] processor; and

[0047] a memory for storing executable instructions of the processor;

[0048] Wherein, the processor is configured to implement the cutting force prediction method for the weak-rigidity tool cutting process based on the slip line method described in the first aspect above by executing the executable instructions.

[0049] The present invention provides a method for predicting cutting forces during the cutout process of a weak-rigidity tool based on a slip-line approach. This method, based on slip-line field theory, reveals the mechanism of cutting force formation under the influence of negative shear and analyzes the influence of flank interference on cutting forces. This method, developed for the cutout process of a weak-rigidity tool, achieves analytical modeling and theoretical prediction of cutting forces for the first time. Compared with Reference 1, this method is more applicable to cutting force prediction during the cutout process of a weak-rigidity tool.

[0050] By predicting the cutting force, tool deformation can be predicted, and then machining error can be predicted, which can also guide the selection of machining parameters.

[0051] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings are incorporated into and constitute a part of this specification, illustrate embodiments consistent with the present invention, and together with the description, serve to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and it is clear that those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0053] Figure 1 A method flow chart of an exemplary embodiment of the present invention;

[0054] Figure 2 Schematic diagram of a slip line field model facing negative shear effect according to an exemplary embodiment of the present invention.

[0055] Figure 3 This is a diagram showing the results of a cutting experiment conducted on exemplary embodiment 1 of the present invention. DETAILED DESCRIPTION

[0056] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0057] In addition, the accompanying drawings are merely schematic illustrations of the present invention and are not necessarily drawn to scale. Identical reference numerals in the figures denote identical or similar parts, and thus repetitive descriptions thereof will be omitted. Some of the blocks shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0058] To address the shortcomings and deficiencies of existing technologies, this example embodiment provides a method for predicting the cutting force during the cut-out process of a weak-rigidity tool based on a slip-line approach. This method first plots the negative shear effect slip-line field and, based on slip-line field theory, calculates the cutting force generated by the negative shear effect. It then determines whether flank interference occurs based on the geometric and kinematic characteristics of the weak-rigidity tool and proposes a method for calculating the interference force generated when flank interference occurs. Ultimately, this method forms a cutting force prediction method for the cut-out process of a weak-rigidity tool.

[0059] Expected technical effect: The cutting force prediction method for the cutting-out process of a weak-rigidity tool provided by the present invention can accurately predict the cutting force for the cutting-out process of a weak-rigidity tool by establishing theoretical modeling.

[0060] Specifically, the following steps may be included:

[0061] Step 1: Observe the radius r of the arc-shaped cutting edge e .

[0062] Step 2: Consult the material manual and supplier data to obtain the Johnson-Cook constitutive model parameter A of the workpiece material JC 、B JC、C JC 、m JC and n JC , and obtain the specific heat capacity c of the workpiece material s , melting point T m and density ρ.

[0063] Step 3: Conduct tool-workpiece friction experiment and measure tool-workpiece friction coefficient μ r .

[0064] Step 4: Refer to the attached Figure 2 , draw the negative shear effect slip line field and discretize the workpiece boundary.

[0065] Step 5: Refer to the attached Figure 2 , passing through the lowest point E of the arc-shaped cutting edge, making a ray along the direction of movement of the workpiece, and intersecting the boundary of the workpiece at point R.

[0066] Step 6: Refer to the attached Figure 2 Assuming that no negative shearing effect occurs during the cutting process and the shear surface intersects the workpiece boundary at point D above the line segment ER, the power consumption P of the cutting process at this time is calculated based on the workpiece material parameters obtained in the step by the method disclosed in the literature "D.-Y.Wen, M.Wan, S.-C.Linghu, W.-H.Zhang, A slip-line field model for independently characterizing shearing and ploughing effects in metal cutting processes, Wear 556-557(2024)205504". c .

[0067] Step 7: Refer to the attached Figure 2 Assuming that no negative shear effect occurs during the cutting process, and the negative shear surface intersects the workpiece boundary at point T below the line segment ER, the negative shear angle is calculated by the following formula:

[0068]

[0069] Where x b y is the horizontal distance from point T to the lowest point of the arc-shaped cutting edge, b It is the vertical distance from point T to the lowest point of the arc-shaped cutting edge.

[0070] Step 8. Calculate the shear strain γ on the negative shear surface using the following formula.

[0071]

[0072] Where h1 is the distance from the lower vertex of the metal dead zone to the machined surface, which is determined by referring to the method disclosed in the literature “M. Wan, D.-Y. Wen, Y.-C. Ma, W.-H. Zhang, On material separation and cutting force prediction in micromilling through involving the effect of dead metal zone, International Journal of Machine Tools and Manufacture 146(2019)103452”.

[0073] Step 9. Calculate the shear strain rate on the negative shear surface using the following formula:

[0074]

[0075] Where, v c is the cutting speed.

[0076] Step 10: Calculate the shear stress τ on the negative shear surface according to the method disclosed in the literature "D.-Y. Wen, M. Wan, S.-C. Linghu, W.-H. Zhang, A slip-linefield model for independently characterizing shearing and ploughing effects in metal cutting processes, Wear 556-557 (2024) 205504". n .

[0077] Step 10. Calculate the normal stress σ on the negative shear surface by the following formula n .

[0078]

[0079] Step 11. Calculate the tangential cutting force F generated by the negative shear surface using the following formula: t-n and normal cutting force F n-n .

[0080]

[0081] Where b is the cutting width.

[0082] Step 12: Calculate the negative shear surface cutting power P by the following formula n .

[0083] Pn =F t-n v c

[0084] Step 13: Calculate the friction coefficient μ of the rake face using the following formula.

[0085]

[0086] Where, α e is the equivalent rake angle, which is determined by referring to the method disclosed in the document “M. Wan, D.-Y. Wen, Y.-C. Ma, W.-H. Zhang, On material separation and cutting force prediction in micro milling through involving the effect of dead metal zone, International Journal of Machine Tools and Manufacture 146 (2019) 103452”.

[0087] Step 14: Calculate the friction coefficient μ0 between the tool and the chip using the method disclosed in the document “D.-Y. Wen, M. Wan, S.-C. Linghu, W.-H. Zhang, Aslip-line field model for independently characterizing shearing and ploughing effects in metal cutting processes, Wear 556-557 (2024) 205504”.

[0088] Step 15, refer to the attached Figure 1 Calculate the negative shear surface corresponding to each discrete point on the workpiece boundary below the line segment ER according to steps 6 to 12, and record the minimum negative shear surface consumption cutting power P that satisfies μ>μ0 n .

[0089] Step 16: If P n ≥P c, the tangential cutting force F at this time is calculated by the method disclosed in the document "D.-Y.Wen, M.Wan, S.-C.Linghu, W.-H.Zhang, Aslip-line field model for independently characterizing shearing and ploughing effects in metal cutting processes, Wear 556-557(2024)205504" t and normal cutting force F n , and skip steps 17 to 25 and proceed to step 26. n <P c , execute steps seventeen to twenty-six.

[0090] Step 17: Let the current time be t, and the tangential cutting force F generated by the negative shear surface based on the solution of step 11 t-n and normal cutting force F n-n The tool position coordinates (x) after deformation are calculated by the method disclosed in the literature “M. Wan, D.-Y. Wen, W.-H. Zhang, Y. Yang, Prediction of cutting forces in flexible micro milling processes by considering the change of instantaneous cutting direction, Journal of Manufacturing Processes 90 (2023) 180–195”. t ,y t ).

[0091] Step 18: Record the tool position coordinates at the previous moment t-dt as (x t-dt ,y t-dt ), let the tool back angle be k0, and calculate the displacement direction κ by the following formula.

[0092]

[0093] If the calculation result shows that κ>κ0, execute step 19, skip steps 20 to 25, and then execute step 26; otherwise, skip step 19 and execute steps 20 to 26.

[0094] Step 19: Calculate the tangential cutting force F at this time using the following formula: t and normal cutting force F n .

[0095]

[0096] Step 20: Let the tangential force F generated by the flank interference at the current time t be t-i and the normal force F n-i Both are equal to 0.

[0097] Step 21. Calculate the acceleration a of the tool cutting edge by solving the following equation.

[0098]

[0099] Where, F t,0 is the tangential cutting force at the previous moment t-dt, F n,0 is the normal cutting force at the previous moment t-dt, r is the tool radius, l is the tool overhang length, and ρ is the tool material density.

[0100] Step 22: Find the tool position coordinates (x t ,y t ):

[0101]

[0102] Step 23: Position coordinates (x t ,y t ), the tangential cutting force F at the current moment t is calculated by the method disclosed in the literature “M. Wan, D.-Y. Wen, W.-H. Zhang, Y. Yang, Prediction of cutting forces in flexible micromilling processes by considering the change of instantaneous cutting direction, Journal of Manufacturing Processes 90 (2023) 180–195” t and normal cutting force F n .

[0103] Step 24: Calculate the tangential force F generated by the flank interference at the current time t using the following formula: t-i and the normal force F n-i :

[0104]

[0105] Step 25: Loop step 21 to step 24 to obtain the tangential cutting force F. t and normal cutting force F n Until the difference is less than the allowable error range.

[0106] Step 26: Let t=t+dt, and repeat steps 4 to 26 until the cutting process is completed.

[0107] Example 1

[0108] Select the overhang length l = 20 mm, radius r = 1.25 mm, and the cutting edge blunt radius r e =0.015 mm, the tool rake angle is 10 degrees, the tool back angle κ0 = 7 degrees, the aluminum alloy Al 7050-T7451 cutting experiment verification, the undeformed chip thickness h = 0.05 mm, the cutting speed v c =89 mm / s, room temperature T m =0 degrees Celsius, cutting width b = 0.5 mm.

[0109] Step 1: Observe the radius r of the arc-shaped cutting edge e =0.015 mm.

[0110] Step 2: Consult the material manual and supplier data to obtain the Johnson-Cook constitutive model parameter A of the workpiece material JC =500 MPa, B JC =240 MPa, C JC =0.003, m JC =2.5 and n JC =0.22, and obtain the specific heat capacity c of the workpiece material s =963 joules per kilogram per degree, melting point T m = 630 degrees and density ρ = 2.8 grams per cubic centimeter.

[0111] Step 3: Conduct tool-workpiece friction experiment and measure tool-workpiece friction coefficient μ r =0.25.

[0112] Step 4: Refer to the attached Figure 2 , draw the negative shear effect slip line field and discretize the workpiece boundary.

[0113] Step 5: Refer to the attached Figure 2 , passing through the lowest point E of the arc-shaped cutting edge, making a ray along the direction of movement of the workpiece, and intersecting the boundary of the workpiece at point R.

[0114] Step 6: Refer to the attached Figure 2Assuming that no negative shearing effect occurs during the cutting process, and that the shearing surface intersects the workpiece boundary at point D above the line segment ER, the power consumption P during the cutting process is calculated using the method disclosed in the literature “D.-Y. Wen, M. Wan, S.-C. Linghu, W.-H. Zhang, A slip-line field model for independently characterizing shearing and ploughing effects in metal cutting processes, Wear 556-557 (2024) 205504”. c .

[0115] Step 7: Refer to the attached Figure 2 Assuming that no negative shear effect occurs during the cutting process, and the negative shear surface intersects the workpiece boundary at point T below the line segment ER, the negative shear angle is calculated by the following formula:

[0116]

[0117] Where x b y is the horizontal distance from point T to the lowest point of the arc-shaped cutting edge, b It is the vertical distance from point T to the lowest point of the arc-shaped cutting edge.

[0118] Step 8. Calculate the shear strain γ on the negative shear surface using the following formula.

[0119]

[0120] Where h1 is the distance from the lower vertex of the metal dead zone to the machined surface, which is determined by referring to the method disclosed in the literature “M. Wan, D.-Y. Wen, Y.-C. Ma, W.-H. Zhang, On material separation and cutting force prediction in micromilling through involving the effect of dead metal zone, International Journal of Machine Tools and Manufacture 146(2019)103452”.

[0121] Step 9. Calculate the shear strain rate on the negative shear surface using the following formula:

[0122]

[0123] Where, v cis the cutting speed.

[0124] Step 10: Calculate the shear stress τ on the negative shear surface according to the method disclosed in the literature "D.-Y. Wen, M. Wan, S.-C. Linghu, W.-H. Zhang, A slip-linefield model for independently characterizing shearing and ploughing effects in metal cutting processes, Wear 556-557 (2024) 205504". n .

[0125] Step 10. Calculate the normal stress σ on the negative shear surface by the following formula n .

[0126]

[0127] Step 11. Calculate the tangential cutting force F generated by the negative shear surface using the following formula: t-n and normal cutting force F n-n .

[0128]

[0129] Where b is the cutting width.

[0130] Step 12: Calculate the negative shear surface cutting power P by the following formula n .

[0131] P n =F t-n v c

[0132] Step 13: Calculate the friction coefficient μ of the rake face using the following formula.

[0133]

[0134] Where, α eis the equivalent rake angle, which is determined by referring to the method disclosed in the document “M. Wan, D.-Y. Wen, Y.-C. Ma, W.-H. Zhang, On material separation and cutting force prediction in micro milling through involving the effect of dead metal zone, International Journal of Machine Tools and Manufacture 146 (2019) 103452”.

[0135] Step 14: Calculate the friction coefficient μ0 between the tool and the chip using the method disclosed in the document “D.-Y. Wen, M. Wan, S.-C. Linghu, W.-H. Zhang, Aslip-line field model for independently characterizing shearing and ploughing effects in metal cutting processes, Wear 556-557 (2024) 205504”.

[0136] Step 15, refer to the attached Figure 1 Calculate the negative shear surface corresponding to each discrete point on the workpiece boundary below the line segment ER according to steps 6 to 12, and record the minimum negative shear surface consumption cutting power P that satisfies μ>μ0 n .

[0137] Step 16: If P n ≥P c , the tangential cutting force F at this time is calculated by the method disclosed in the document "D.-Y.Wen, M.Wan, S.-C.Linghu, W.-H.Zhang, Aslip-line field model for independently characterizing shearing and ploughing effects in metal cutting processes, Wear 556-557(2024)205504" t and normal cutting force F n , and skip steps 17 to 25 and proceed to step 26. n <P c , execute steps seventeen to twenty-six.

[0138] Step 17: Let the current time be t, and the tangential cutting force F generated by the negative shear surface based on the solution of step 11 t-n and normal cutting force F n-n The tool position coordinates (x) after deformation are calculated by the method disclosed in the literature “M. Wan, D.-Y. Wen, W.-H. Zhang, Y. Yang, Prediction of cutting forces in flexible micro milling processes by considering the change of instantaneous cutting direction, Journal of Manufacturing Processes 90 (2023) 180–195”. t ,y t ).

[0139] Step 18: Record the tool position coordinates at the previous moment t-dt as (x t-dt ,y t-dt ), let the tool back angle be κ0, and calculate the displacement direction κ by the following formula.

[0140]

[0141] If the calculation result shows that κ>κ0, execute step 19, skip steps 20 to 25, and then execute step 26; otherwise, skip step 19 and execute steps 20 to 26.

[0142] Step 19: Calculate the tangential cutting force F at this time using the following formula: t and normal cutting force F n .

[0143]

[0144] Step 20: Let the tangential force F generated by the flank interference at the current time t be t-i and the normal force F n-i Both are equal to 0.

[0145] Step 21. Calculate the acceleration a of the tool cutting edge by solving the following equation.

[0146]

[0147] Where, F t,0 is the tangential cutting force at the previous moment t-dt, F n,0 is the normal cutting force at the previous moment t-dt, r is the tool radius, which is 1.25 mm, l is the tool overhang length, which is 20 mm, and ρ is the tool material density, which is 14.5 g / cm3.

[0148] Step 22: Find the tool position coordinates (x t ,y t ):

[0149]

[0150] Step 23: Position coordinates (x t ,y t ), the tangential cutting force F at the current moment t is calculated by the method disclosed in the literature “M. Wan, D.-Y. Wen, W.-H. Zhang, Y. Yang, Prediction of cutting forces in flexible micromilling processes by considering the change of instantaneous cutting direction, Journal of Manufacturing Processes 90 (2023) 180–195” t and normal cutting force F n .

[0151] Step 24: Calculate the tangential force F generated by the flank interference at the current time t using the following formula: t-i and the normal force F n-i :

[0152]

[0153] Step 25: Loop step 21 to step 24 to obtain the tangential cutting force F. t and normal cutting force F n Until the difference is less than 0.0001N.

[0154] Step 26: Let t = t + dt, and repeat steps 4 to 26 until the cutting process is completed. Plot the tangential cutting force F during the cutting process. t and normal cutting force F n Curve, get attached Figure 3 .

[0155] Through the above steps, the present invention can be obtained by using the overhang length l = 20 mm, radius r = 1.25 mm, and cutting edge blunt radius r e = 0.015 mm, the tool rake angle is 10 degrees, the tool back angle κ0 = 7 degrees, the undeformed chip thickness h = 0.05 mm, the cutting speed v c =89 mm / s, room temperature T m= 0 degrees Celsius, cutting width b = 0.5 mm, cutting force prediction results of aluminum alloy Al 7050-T7451, refer to the attached Figure 2 By attaching Figure 2 It can be seen that the cutting force results calculated by the present invention can well predict the downward trend of the cutting force during the tool cutting process, and are in good agreement with the actual measured results of the cutting force experiment. It can be seen from the figure that the prediction results of the method in Document 1 transiently change to 0 at the theoretical cutting moment of the cutting edge, and cannot predict the downward trend of the cutting force during the tool cutting process, which proves the effectiveness of the cutting force prediction method proposed in the present invention for the weak stiffness tool cutting process.

[0156] Furthermore, the above-described figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention and are not intended to be limiting. It is readily understood that the processes illustrated in the above-described figures do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0157] Other embodiments of the present invention will readily occur to those skilled in the art after considering the specification and practicing the invention herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the claims.

[0158] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings and that various modifications and variations can be made without departing from the scope thereof, which is limited only by the appended claims.

Claims

1. A method for predicting cutting force during the cutting process of a weak-rigidity tool based on a slip line method, characterized in that: The method comprises: Draw the negative shear effect slip line field, and calculate the tangential cutting force F generated by the negative shear surface based on the negative shear effect slip line field t-n and normal cutting force F n-n ; Tangential cutting force F generated by negative shear surface t-n Calculate the cutting power P consumed by the negative shear surface n ; Tangential cutting force F generated by negative shear surface t-n and normal cutting force F n-n Calculate the friction coefficient μ of the rake face and record the minimum negative shear surface consumption cutting power P that satisfies μ>μ0 n , where μ0 is the friction coefficient between the tool and the chip; If P n ≥P c , then calculate the tangential cutting force F at the current moment t and normal cutting force F n Among them, P c The power consumed by the cutting process at the current moment; If P n <P c , then calculate the displacement direction κ based on the tool position coordinates at the current moment and the previous moment; if κ>κ0, calculate the tangential cutting force F at the current moment t and normal cutting force F n If κ≤κ0, the tangential cutting force F at the current moment is calculated based on the tangential force and normal force generated by the flank interference. t and normal cutting force F n ; Where κ0 is the tool back angle.

2. The method according to claim 1, characterized in that The tangential cutting force F generated by the negative shear surface is calculated based on the negative shear effect slip line field. t-n and normal cutting force F n-n ;include: Calculate the shear strain on the negative shear surface; Calculate the shear strain rate on the negative shear surface based on shear strain, negative shear angle, cutting speed, and cutting edge radius; Calculate the shear stress on the negative shear surface based on the shear strain rate; The tangential cutting force F generated by the negative shear surface is calculated based on the shear stress, normal stress, negative shear angle, cutting width, and tool position coordinates on the negative shear surface. t-n and normal cutting force F n-n .

3. The method according to claim 2, characterized in that The tangential cutting force F generated by the negative shear surface is calculated based on the shear stress, normal stress, negative shear angle, cutting width, and tool position coordinates on the negative shear surface. t-n and normal cutting force F n-n , using the following formula: Among them, τ n is the shear stress, σ n is the normal stress, is the negative shear angle, b is the cutting width, (x t ,y t ) is the tool position coordinate at the current moment t.

4. The method according to claim 1, wherein The tangential cutting force F generated based on the negative shear surface t-n Calculate the cutting power P consumed by the negative shear surface n , using the following formula: P n =F t-n v c Among them, v c is the cutting speed.

5. The method according to claim 1, characterized in that The tangential cutting force F generated based on the negative shear surface t-n and normal cutting force F n-n To calculate the friction coefficient μ of the rake face, use the following formula: Among them, α e is the equivalent rake angle.

6. The method according to claim 1, characterized in that The displacement direction κ is calculated based on the tool position coordinates at the current moment and the previous moment using the following formula: Among them, (x t-dt ,y t-dt ) is the position coordinate at the previous moment t-dt.

7. The method according to claim 1, characterized in that The tangential cutting force F at the current moment is calculated based on the tangential force and normal force generated by the flank interference. t and normal cutting force F n ,include: Let the tangential force F generated by the flank interference at the current moment be t-i and the normal force F n-i are all equal to 0; The position coordinates of the deformed weak-rigidity tool that meets the conditions are sought through numerical methods; Calculate the tangential cutting force and normal cutting force at the current moment based on the position coordinates of the weak-rigidity tool after deformation; Update the tangential force F generated by the flank interference at the current moment based on the tangential cutting force and normal cutting force at the current moment t-i and the normal force F n-i ; The updated tangential force F generated by the flank interference at the current moment t-i and the normal force F n-i Circular solution of tangential cutting force F t and normal cutting force F n Until the difference between the two cutting forces meets the requirements.

8. The method according to claim 7, characterized in that The numerical method is used to find the position coordinates of the weak stiffness tool after deformation that meets the conditions, using the following formula: Among them, μ r is the tool-workpiece friction coefficient, and a is the acceleration of the tool cutting edge.

9. The method according to claim 8, characterized in that The formula for calculating the acceleration a of the cutting edge of the tool is as follows: Among them, F t,0 is the tangential cutting force at the previous moment t-dt, F n,0 is the normal cutting force at the previous moment t-dt, r is the tool radius, l is the tool overhang length, ρ is the tool material density, and a is the acceleration of the tool cutting edge.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for predicting cutting force during a cutting process of a weak-rigidity tool based on a slip line method according to any one of claims 1 to 9 is implemented.

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