Grinding support device, display device and program

Abstract

To provide a grinding support device that can determine tangential resistance in compliance with various grinding conditions, without using an experimental value of specific grinding energy.SOLUTION: Information for specifying a grinding condition for making a grindstone cut into a material to be ground by a cutting-in amount, while rotating the grindstone to grind the material to be ground while moving the material relatively with respect to the grindstone and information for specifying a physical property value of the material to be ground are inputted to an input part. A calculation part calculates tangential resistance applied in a circumferential direction to a working plane of the grindstone to determine a predictive value of tangential resistance, on the basis of the information for specifying the grinding condition and the information for specifying the physical property value inputted to the input part. Information showing the predictive value of tangential resistance determined by the calculation part is outputted from an output part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a grinding support device, a display device, and a program. [Background technology]

[0002] When determining the grinding conditions, it is necessary to find conditions that can be processed by a grinding machine based on the required specifications such as roughness, waviness, geometric accuracy, and processing time. Conventionally, the optimal processing conditions have been determined by trial and error, using accumulated processing data, the know-how of skilled workers, and the knowledge of manufacturers of grinding wheels and grinding machines, as well as research institutes such as universities, to carry out trial processing under the determined processing conditions.

[0003] Grinding resistance that occurs during grinding is expressed by tangential resistance acting in the tangential direction of the working surface (peripheral surface) of the grinding wheel, and normal resistance acting in the normal direction of the working surface of the grinding wheel. In particular, tangential resistance is directly connected to the spindle power of the grinding machine (the power that rotates the grinding wheel), and the magnitude of tangential resistance determines whether or not processing is possible with the existing grinding machine. In addition, tangential resistance affects the processing energy efficiency.

[0004] In addition, a part of the grinding resistance is converted into thermal energy, which becomes grinding heat. Grinding heat is a factor in the occurrence of defects such as grinding cracks and grinding warping. However, grinding resistance varies greatly depending on grinding conditions such as the material of the workpiece, the cutting depth of the grinding wheel, the rotation speed of the grinding wheel, and the moving speed of the workpiece relative to the grinding wheel, making it difficult to predict.

[0005] A conventional prediction formula for grinding resistance will be described. The amount of work done by the grinding wheel on the workpiece depends on the volume of the workpiece that is removed. This volume of the workpiece is proportional to the energy that the grinding wheel applied to the workpiece. Considering this in terms of unit time, the grinding wheel output L [kW] is expressed as the volume of the workpiece that is removed, and the removal rate q [mm 3 / s]. The wheel output L is proportional to the wheel peripheral speed V s and tangent resistance F t The removal volume rate q is the product of the grinding width b and the cutting depth Z c and the moving speed of the workpiece V wIf the proportional constant between the grindstone output L and the removal / accumulation rate q is denoted as k, the following formula is obtained:

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[0006] By transforming equation (1), the following equation is obtained.

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[0007] The proportionality constant k is the grinding energy per unit volume [J / mm 3 ], which is called the specific grinding energy. In Patent Document 2, the tangential resistance F t A method for finding this is shown. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] Koichi Ichihara, Study on the grinding mechanism of multi-thread dressing wheel, 2nd report: Evaluation method of grinding efficiency and influence of workpiece material, ABTEC2020 [Non-Patent Document 2] Katsuo Shoji, Grinding Engineering, Yokendou (2004), Chapter 5, page 88 Summary of the Invention [Problem to be solved by the invention]

[0009] The method shown in Patent Document 2 calculates the tangential resistance F from the specific grinding energy. t However, it is not possible to predict the tangential resistance when grinding a work material for which there is no data on the specific grinding energy.

[0010] In the method shown in formula (1), formula (2) and non-patent document 2, the consumed grinding energy is proportional only to the removed volume, and the difference in efficiency due to the grinding method cannot be explained. For example, the removed volume is the same when grinding once with a cutting depth of 10 μm and when grinding ten times with a cutting depth of 1 μm, but it is known that the consumed grinding energy is greater when grinding ten times with a cutting depth of 1 μm in actual grinding processing. This can be understood as being because the smaller the chip size, the cut surface area per unit volume increases inversely proportional to the chip size, and the shear energy of the chip increases.

[0011] However, the conventional tangential resistance prediction method does not reflect the effect of chip size, and is unable to express the phenomenon that the grinding resistance per unit cutting depth increases as the cutting depth decreases. In addition, the experimental value of the specific grinding energy varies depending on the grinding conditions, such as the dressing conditions and cutting depth, at the time of measurement. Therefore, if the grinding conditions when the grinding resistance is to be predicted are different from the grinding conditions when the experimental value of the specific grinding energy was obtained, the prediction accuracy of the grinding resistance decreases.

[0012] An object of the present invention is to provide a grinding support device and a program capable of determining tangential resistance according to various grinding conditions without using an experimental value of specific grinding energy. [Means for solving the problem]

[0013] According to one aspect of the present invention, an input unit for inputting information specifying grinding conditions when cutting a workpiece with a cutting depth while rotating the grinding wheel and moving the workpiece relatively with respect to the grinding wheel, and information specifying physical property values ​​of the workpiece; a calculation unit that calculates a tangential resistance applied in a circumferential direction of a working surface of the grinding wheel based on information specifying the grinding conditions and physical property values ​​of the workpiece inputted to the input unit, and obtains a predicted tangential resistance value; an output unit that outputs information representing the predicted tangential resistance value calculated by the calculation unit; A grinding support device comprising:

[0014] According to another aspect of the invention, a message prompting the user to input information specifying grinding conditions when the grinding wheel is rotated while cutting into the workpiece by a cutting depth and grinding the workpiece while moving the workpiece relatively to the grinding wheel, and information specifying physical property values ​​of the workpiece; A display device is provided which displays information representing a predicted tangential resistance value obtained by calculating the tangential resistance applied in the circumferential direction of the working surface of the grinding wheel based on the input grinding conditions and information specifying the physical properties of the workpiece.

[0015] According to yet another aspect of the present invention, a function of acquiring information specifying grinding conditions and physical property values ​​of the workpiece when cutting the grinding wheel into the workpiece by a cutting depth while rotating the grinding wheel and moving the workpiece relatively to the grinding wheel to perform grinding; A function of calculating a predicted value of a tangential resistance applied in a circumferential direction of a working surface of the grinding wheel based on information specifying the grinding conditions and physical properties of the workpiece; A function of outputting the predicted value of the tangential resistance; A program for causing a computer to realize the above is provided. Effect of the Invention

[0016] It is possible to obtain the tangential resistance according to various workpiece materials and grinding conditions without using experimental values ​​of specific grinding energy. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a block diagram of a grinding support device according to a first embodiment, and a schematic perspective view of a grinding machine that performs grinding supported by the grinding support device. [Diagram 2] FIG. 2 is a flow diagram for explaining the procedure of calculations executed by the calculation unit. [Diagram 3]FIG. 3A is a schematic diagram of the grinding wheel and the workpiece being cut by the grinding wheel, as viewed from the y direction, and FIG. 3B is a cross-sectional view parallel to the yz plane of the grinding wheel and the workpiece. [Figure 4] Figure 4 is a table showing the physical properties of the workpiece, grinding conditions, shear area S (Figure 2), predicted equivalent shear stress τeq (Figure 2), friction coefficient setting value μ, predicted tangential resistance Ft_pre, predicted normal resistance Fn_pre, experimental tangential resistance Ft_exp, and experimental normal resistance Fn_exp. [Diagram 5] FIG. 5 is a graph showing a comparison between the predicted tangential resistance values ​​Ft_pre and the experimental tangential resistance values ​​Ft_exp obtained for each of the five types of workpiece materials. [Figure 6] FIG. 6 is a table showing the grinding conditions, the shear area S (FIG. 2), the predicted equivalent shear stress τeq (FIG. 2), the predicted tangential resistance Ft_pre, the predicted normal resistance Fn_pre, the experimental tangential resistance Ft_exp, and the experimental normal resistance Fn_exp. [Figure 7] FIG. 7 is a graph showing a comparison between the predicted tangential resistance values ​​Ft_pre and the experimental tangential resistance values ​​Ft_exp determined for each cutting-in amount Zc. [Figure 8] FIG. 8 is a schematic diagram of a workpiece to be cut by the grindstone and the grindstone 54 viewed from the y direction, for explaining a grinding support device according to the second embodiment. [Figure 9] FIG. 9 is a graph that shows, based on a mathematical model, the magnitudes of the normal resistance Fn and the tangential resistance Ft at any point on the contact arc PB0PB1 (FIG. 8). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 1 is a block diagram of a grinding support device 30 according to a first embodiment, and a schematic perspective view of a grinding machine 10 that performs grinding supported by the grinding support device 30. A movable table 52 is supported on a base 50 via a table guide mechanism 51 so as to be capable of reciprocating in one direction in a horizontal plane. An xyz Cartesian coordinate system is defined in which the moving direction of the movable table 52 is the x direction, and the vertical downward direction is the positive direction of the z axis. A workpiece 60 is supported on the movable table 52.

[0019] The grindstone head 53 is supported above the movable table 52. The grindstone head 53 is movable up and down and in a horizontal plane in a direction (y direction) perpendicular to the moving direction of the movable table 52. For example, a saddle is supported so as to be movable in the x direction along the traverse direction guide rail 55, and the grindstone head 53 is supported so as to be movable up and down relative to the saddle.

[0020] A grindstone 54 is attached to the lower end of the grindstone head 53. The grindstone 54 has a working surface along the side surface of a cylinder, and its central axis is parallel to the y-axis direction. The grindstone head 53 is lowered so that the lower end of the grindstone 54 is slightly below the surface of the workpiece 60, and the workpiece 60 is moved in the grinding direction (x direction) while rotating the grindstone 54, thereby grinding the workpiece 60. The length in the z direction from the surface of the workpiece 60 to the lower end of the grindstone 54 during grinding is called the cutting depth.

[0021] The area ground when the grindstone 54 is cut into the workpiece 60 and moved in the x direction from one end of the workpiece 60 to the other is called a "pass." By repeating the procedure of shifting the grindstone head 53 in the traverse direction (y direction) and the procedure of grinding one pass, the entire upper surface (machined surface) of the workpiece 60 can be ground.

[0022] The grinding support device 30 includes an input unit 31, a calculation unit 32, an output unit 33, and a storage unit . Information specifying the grinding conditions when grinding is performed and information specifying the physical property values ​​of the workpiece are input to the input unit 31. As the input unit 31, a keyboard, a touch panel, a combination of a display and a pointing device, a reader / writer for removable media, a communication device, or the like is used.

[0023] The calculation unit 32 calculates a predicted value of tangential resistance applied in the circumferential direction of the working surface of the grinding wheel 54 (hereinafter referred to as a predicted tangential resistance value) based on information specifying the grinding conditions and information specifying the physical properties of the workpiece input to the input unit 31. For example, the calculation unit 32 includes a microprocessing unit (MPU) and realizes the function of calculating the predicted tangential resistance value by executing a program stored in the storage unit 34.

[0024] Information representing the predicted tangential resistance value calculated by the calculation unit 32 is output from the output unit 33. As the output unit 33, for example, a display device, a reader / writer for removable media, a communication device, or the like is used.

[0025] When the output unit 33 is a display device, it is preferable to display a message prompting the input of information specifying the grinding conditions and information specifying the physical properties of the workpiece. When the user sees this message and inputs information specifying the grinding conditions and information specifying the physical properties of the workpiece into the input unit 31, the calculation unit 32 calculates a tangential resistance prediction value, and it is preferable to display information indicating the calculated tangential resistance prediction value on the display device.

[0026] The display device may display, as information representing the predicted tangential resistance value, information indicating whether or not machining is possible with an existing grinding machine based on the predicted tangential resistance value. Also, the display device may display, as information representing the predicted tangential resistance value, information indicating how much grinding power is required for a user who is considering the specifications of a grinding machine based on the predicted tangential resistance value. In this way, the display device can determine the predicted tangential resistance value based on information specifying the grinding conditions and the physical properties of the workpiece, and display the specifications (conditions) of the grinding machine required by the user from the predicted tangential resistance value.

[0027] 2 is a flow chart for explaining the procedure of calculation executed by the calculation unit 32. As the physical property value of the workpiece 60 (FIG. 1), for example, the tensile strength σ max , shear strength τ max , Elongation E L The value of tensile strength σ max and shear strength τ maxIt is known that the following relationship exists between them based on von Mises' shear energy theory:

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[0028] Grinding conditions are wheel diameter D and cutting depth Z. c , grinding width b, grinding wheel rotation speed N, grinding material movement speed V w , wheel peripheral speed V s The value of is input to the input unit 31 (FIG. 1). s The following relationship exists between the grinding wheel diameter D and the grinding wheel rotation speed N.

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[0029] The calculation unit 32 calculates the tensile strength σ max and shear strength τ max One input value of and elongation E L Based on the input values, the equivalent shear stress is calculated and the equivalent shear stress predicted value τ eq Calculate the equivalent shear stress τ eq The calculation method of will be described later. Furthermore, the calculation unit 32 calculates the grinding wheel diameter D, the cutting depth Z c , grinding width b, grinding wheel rotation speed N, workpiece movement speed V w The shear area is calculated from the above to obtain the calculated shear area value S. The method for calculating the shear area S will be explained later.

[0030] The calculation unit 32 calculates the tangential resistance prediction value F based on the following formula: t_pre Request.

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[0031] Next, referring to FIG. 3A to FIG. 4, the equivalent shear stress predicted value τ eq The method for calculating the calculated shear area S will be explained.

[0032] 3A is a schematic diagram of the grindstone 54 and the workpiece 60 cut by the grindstone 54 as viewed from the y direction, and FIG. 3B is a cross-sectional view parallel to the yz plane of the grindstone 54 and the workpiece 60. The length in the z direction from the surface of the workpiece 60 to the lowest point of the grindstone 54 is the cutting depth Z. c In reality, the workpiece 60 moves in the positive direction of the x-axis relative to the grindstone 54, but in FIG. 3A, the grindstone 54 is shown moving in the negative direction of the x-axis from the position shown by the solid line to the position shown by the dashed line relative to the workpiece 60. That is, the grindstone 54 moves in the negative direction of the x-axis at a moving speed V w At the lowest point of the grindstone 54, the working surface of the grindstone 54 moves in the same direction as the moving direction of the grindstone 54 (the negative direction of the x-axis) at a peripheral speed V s The grindstone 54 rotates so as to move in a circular motion.

[0033] The grinding width b (FIG. 3B) is the dimension in the y direction of the portion of the workpiece 60 that is ground by the grindstone .

[0034] The lowest point of the grinding wheel 54 shown by the solid line is P A0 and the intersection point between the grinding wheel 54 and the surface of the workpiece 60 shown by the solid line is P A1 The lowest point of the grindstone 54 shown by the dashed line is P B0 and the intersection point between the grindstone 54 and the surface of the workpiece 60 shown by the dashed line is P B1 Point P A0 From point P A1 The grindstone 54 comes into contact with the workpiece 60 in the arc portion up to the point P on the work surface. This arc is called the contact arc.A0 is point P A1 During the time that the grinding wheel 54 reaches the position shown by the broken line, the grinding wheel 54 moves to the position shown by the broken line. This movement distance is called the movement amount λ per contact arc. c Let us say that point P A0 From point P A1 The length of the contact arc to point P B0 From point P B1 The length of the contact arc is equal to the contact arc length L c Let's assume that this is the case.

[0035] Movement per contact arc λ c and contact arc length L c can be calculated using the following formula:

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[0036] The amount of movement of the grinding wheel 54 per contact arc λ c When the contact arc P A0 P A1 , straight line P A1 P B1 , contact arc P B1 P B0 , and the line P B0 P A0 The workpiece 60 in the area surrounded by is cut off and becomes chips. The part that becomes the chip is called the chip part. The cross-sectional length L of the chip part s is approximated by the following formula. Generally, the cutting depth Z c is in the order of μm, and the tangent arc length L c Since is on the order of mm, the following approximation holds:

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[0037] Tangential resistance F t corresponds to the force that shears the shear surface that becomes the chip of the workpiece. The shear force is the contact arc P A0 P A1At this position, the grinding wheel 54 is applied with a tangential frictional force as it drags the workpiece 60 in the circumferential direction. The shear force acts only while the metal bond between the chip side and the side being cut is displaced, deformed, and stretched, and when the metal bond is broken, the shear force becomes zero.

[0038] The displacement of the chip portion relative to the workpiece 60 on the shear surface occurs because the chip portion moves with the working surface of the grinding wheel 54. s If we assume that the metal bond breaks when the grinding wheel 54 is displaced by 100%, the elongation of the workpiece 60 at the shear surface is 100%. However, the elongation of general metal materials is less than 100%. In other words, the shear force is s The metal bond is broken while dragging the chip, and the shear force becomes zero. s The shear force does not occur over the entire length of the pipe.

[0039] Since the deformation strain of the shear plane is considered to be proportional to the elongation of the material 60, the shear fracture stress is proportional to the shear strength τ max Stretch to E L Based on this consideration, the equivalent shear stress prediction value τ eq is defined as follows:

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[0040] Elongation E L The index n attached to the final tangential resistance prediction value F t_pre and tangent resistance F t This is a parameter to compensate for the deviation from the actual measured value. For example, 1.2 is used as the exponent n. th is the shear strength τ max and the equivalent shear stress prediction value τ eq This is a correction factor to match the order of magnitude of shear strength τ max and Elongation LThe value obtained by multiplying and is about two orders of magnitude larger than the shear stress value obtained in the actual machine test, so the correction coefficient η th For example, η th A value of 0.040 is used as the factor.

[0041] Equivalent shear stress prediction value τ eq The reason why there is a difference of about two orders of magnitude between the shear stress value obtained by the actual machine test and the value obtained by the actual machine test is explained below. Just as you can see sparks from the chips during grinding, the chips are subjected to friction and shear forces from the grindstone and instantly reach a high temperature of nearly 1000°C. The area around the chips on the workpiece also becomes hot and softens, causing a significant decrease in shear strength. For example, the tensile strength σ of stainless steel is max It is known that the equivalent shear stress τ decreases by about one order of magnitude when the temperature rises from room temperature to 1000°C. In the actual machine test, the shear stress reflects this decrease in shear strength, whereas the equivalent shear stress prediction value τ eq The calculation of does not reflect the decrease in shear strength due to softening, which is why there is a discrepancy of about two orders of magnitude between the two.

[0042] The calculated shear area S (Fig. 2) is the cross-sectional length L of the chip. s and grinding width b, it can be calculated using the following formula.

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[0043] Equivalent shear stress prediction value τ eq Once the calculated shear area S is obtained, the predicted tangential resistance F can be calculated from equations (5) and (6). t_pre and normal resistance prediction value F n_pre can be calculated.

[0044] The predicted tangential resistance value F obtained by using the grinding support device 30 according to the first embodiment t_pre and normal resistance prediction value F n_pre An evaluation experiment was conducted to confirm the accuracy of the above. Next, the results of the evaluation experiment will be described with reference to Figures 4 and 5. In the evaluation experiment, SUS304, SS400, S55C, NAK55, and FC250 were used as the work material 60.

[0045] FIG. 4 shows the physical properties of the workpiece 60, the grinding conditions, the calculated shear area S (FIG. 2), and the predicted equivalent shear stress τ eq (Fig. 2), friction coefficient setting value μ, tangential resistance prediction value F t_pre , predicted normal resistance F n_pre , experimental value of tangential resistance F t_exp , normal resistance experimental value F n_exp As the physical property value of the work material 60, tensile strength σ max , shear strength τ max , Elongation E L The grinding conditions are the wheel diameter D, the wheel rotation speed N, and the workpiece movement speed V. w , cutting depth Z c , and grinding width b.

[0046] The set friction coefficient value μ may be, for example, a value measured by the method described below. A sample of the grindstone 54 and a sample of the workpiece 60 are prepared. The sample of the grindstone 54 is prepared to have a shape with a flat working surface, for example, a rectangular parallelepiped shape. The working surface of the sample of the grindstone 54 is brought into contact with the surface to be cut of the workpiece 60, and one of the sample of the grindstone 54 and the sample of the workpiece 60 is fixed to the inclined surface.

[0047] When the inclination angle of the slope is gradually increased, the sample of the grindstone 54 and the sample of the workpiece 60 that is not fixed to the slope starts to slide. The tangent of the angle at that time corresponds to the static friction coefficient. This static friction coefficient can be used as the friction coefficient setting value μ.

[0048] In the calculation, the exponent n in formula (9) is set to 1.2, and the correction coefficient η thwas set to 0.040. Note that the exponent n and the correction coefficient η th The value of can be found optimally by carrying out evaluation experiments on various work materials 60.

[0049] Tangential resistance experimental value F t_exp and normal resistance experimental value F n_exp was obtained by grinding the workpiece 60 under the actually given grinding conditions and measuring the force applied to the workpiece 60.

[0050] FIG. 5 shows the predicted tangential resistance F obtained for each of the five types of workpieces 60. t_pre and the experimental value of tangential resistance F t_exp In any of the workpieces 60, the predicted tangential resistance F t_pre is the experimental value of tangent resistance F t_exp It is seen to be in good agreement with

[0051] Furthermore, the cutting depth Z c When the grinding support device 30 according to the first embodiment is used, the tangential resistance prediction value F t_pre , predicted normal resistance F n_pre An evaluation experiment was conducted to confirm the accuracy of the above. The results of the evaluation experiment will be described with reference to Figs. 6 and 7. In the evaluation experiment, FC250 was used as the workpiece 60, and the cutting depth Z c was changed within the range of 1 μm to 20 μm.

[0052] Figure 6 shows the grinding conditions, the calculated shear area S (Figure 2), and the predicted equivalent shear stress τ eq (Fig. 2), predicted tangential resistance F t_pre , predicted normal resistance F n_pre , experimental value of tangential resistance F t_exp , normal resistance experimental value F n_exp 1 is a diagram showing the cutting depth Z c However, evaluation was carried out for five cases of 1 μm, 2 μm, 5 μm, 10 μm, and 20 μm.

[0053] Figure 7 shows the cutting depth Z c The predicted tangential resistance F for each t_preand the experimental value of tangential resistance F t_exp 1 is a graph showing a comparison of the cutting depth Z c In this case, the predicted tangential resistance F t_pre is the experimental value of tangent resistance F t_exp It is seen to be in good agreement with

[0054] Next, the excellent effects of the first embodiment will be described. In the first embodiment, the tangential resistance prediction value F t_pre and normal resistance prediction value F n_pre Therefore, even for workpieces for which there is no data on the specific grinding energy, the predicted tangential resistance F t_pre and normal resistance prediction value F n_pre can be sought.

[0055] The tangential resistance F calculated using the conventional method shown in equation (2) t is the cutting depth Z c However, as an example, the cutting depth Z c Even if the thickness is reduced from 10 μm to 1 μm, the tangent resistance F t It is empirically known that the cutting depth Z does not become 1 / 10. c When the thickness is reduced from 10 μm to 1 μm, the predicted tangential resistance F e_pre is not 1 / 10, but about 1 / 3. This is because the experimental value of the tangential resistance F t_exp In this way, in the first embodiment, various cutting depths Z c Regarding the tangent resistance F t It is possible to predict more accurately.

[0056] Tangential resistance prediction value F t_pre and normal resistance prediction value F n_pre When is obtained, the power required to rotate the grinding wheel 54 (FIG. 1) can be predicted. For example, when a new grinding machine is introduced, the tangential resistance prediction value F t_pre and normal resistance prediction value F n_pre This is useful information for determining the specifications of the grinding machine to be introduced. In addition, when grinding is performed using an existing grinding machine, the tangential resistance prediction value Ft_pre and normal resistance prediction value F n_pre This provides useful information for determining grinding conditions.

[0057] Next, a grinding support device according to a second embodiment will be described. Hereinafter, a description of the configuration common to the grinding support device according to the first embodiment described with reference to Figs. 1 to 7 will be omitted. In the first embodiment, the length L of the cross section of the chip portion shown in formula (8) is s In the second embodiment, it is assumed that shearing occurs over the entire length of the workpiece 60, but in the second embodiment, the tangential resistance and normal resistance are predicted taking into account the friction zone where the working surface of the grindstone 54 slides against the workpiece 60.

[0058] The chips are generated when the abrasive grains or dressing blades bite into the work surface and are removed from the work surface by shear force. As a result, grooves are formed on the work surface where the chips have been removed. From this, the tangential resistance of the grinding wheel 54 can be considered as the resistance to shear fracture acting on the shear surface of the chips.

[0059] Shear force F s is the product of the shear stress and the shear area, so the shear strength τ of the workpiece 60 is max and the shear area S during grinding are calculated using the following formula. In the following formula, the shear area S is transformed using formula (10).

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[0060] FIG. 8 is a schematic diagram of the grindstone 54 and the workpiece 60 being cut by the grindstone 54, viewed from the y direction, and shows the same state as that shown in FIG. 3A.

[0061] From the center point of the grinding wheel 54 shown by the solid line to point P A1 The intersection point of the extension of the radius toward P and the outer circumference of the grinding wheel 54 shown by the dashed line is P m The line segment P A1 P m length to the maximum cutting depth h max The interference between the workpiece 60 and the grindstone 54 is expressed as the point Pm The surface pressure is also maximum at F t Also, point P m It becomes maximum at.

[0062] The friction coefficient between the grindstone 54 and the workpiece 60 is μ, and the contact pressure is σ n If the infinitesimal length in the tangential direction where the contact pressure acts is denoted as dl, the tangential resistance F t is described by the following formula:

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[0063] point P m The contact pressure at σ n_max Then, the contact arc P B0 P B1 Contact pressure σ at any point on n is the point P B0 If we take the origin as the point, it increases almost proportionally to the distance l from the origin. B0 From point P m Distance l to contact arc length L c If we approximate it with (Equation (8)), the contact pressure σ n is expressed by the following formula:

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[0064] The contact pressure σ in Eq. (13) n Substituting this into equation (12), we obtain the following equation.

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[0065] Tangential resistance F t is the shear force F of the workpiece 60 s When the contact resistance exceeds , the chip part moves along the contact arc due to shear fracture, and the tangential resistance F t is the shear force F s The tangent resistance F is equal to t is the shear force F of the workpiece 60 sIf the working surface of the grinding wheel 54 is less than the contact arc P A0 P A1 It slides over, creating frictional resistance.

[0066] Maximum contact pressure σ n_max is the contact stiffness K between the grinding wheel 54 and the workpiece 60 E , point P m Maximum cutting depth h max Using this, it is expressed by the following formula.

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[0067] The distance between successive cutting edges is the contact arc length L c If it is equal to, the maximum cutting depth h max is expressed by the following formula:

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[0068] Substituting equations (15) and (16) into equation (14), the maximum tangential resistance F t_max is obtained by the following formula:

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[0069] Equation (17) is the contact arc length L c Integrating up to the shear force F in equation (11) s and the maximum tangent resistance F in equation (17) t_max Let and be equal to the shear length L s When this is calculated, the following formula is obtained:

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[0070] FIG. 9 shows the contact arc P based on the above mathematical model. B0 P B1 Normal resistance F at any point on n and tangent resistance F t The horizontal axis is a graph showing the magnitude of the point PB0 From point P B1 Contact arc P toward B0 P B1 The vertical axis of the upper and lower graphs corresponds to the normal resistance F n and tangent resistance F t The point of length L1 corresponds to the shear start point, and the point of length L2 corresponds to the point P m (Figure 8). In the section from the origin to length L1, the normal resistance F n Since the friction resistance F is small, the working surface of the grindstone 54 slides on the contact arc. r When the length from the origin exceeds L1, shear begins and the tangential resistance F t is the shear force F s The length at which shear occurs is called the shear length L s It is marked as such.

[0071] In the first embodiment, it is assumed that shear occurs over the entire contact arc as shown in equation (8). In the second embodiment, the section where slip occurs and the section where shear occurs are treated separately.

[0072] Maximum sliding friction resistance is F r_max The average value of friction resistance (hereinafter, the average value of friction resistance F r_ave ) is the maximum sliding friction resistance F r_max Also, the length from the origin to point P is L2. m The normal resistance is maximum at F n_max The average normal resistance F n_ave is the maximum value F n_max is 1 / 2.

[0073] Shear force F s is generated by the displacement of the chip part on the shear surface, and fracture occurs when the deformation amount exceeds the limit of plastic deformation. When the chip part breaks, the tangential resistance F t becomes zero.

[0074] The displacement on the shear plane occurs when the contact surface of the chip moves with the working surface of the grinding wheel 54. The amount of movement is the shear length L s When the shear length is equal to , the chip shear surface is 100% elongated, but the elongation of the physical properties of general metal materials is less than 100%. Therefore, the effective shear length on which the shear force acts is the shear length L s This is the shear force F s E grows L This is equivalent to a 2-fold decrease.

[0075] Therefore, the average value of the tangential resistance when cutting the contact arc (hereinafter, the average tangential resistance F t_ave ) can be calculated by adding the sliding friction resistance and the shear resistance, weighted by the length over which they act, using the following formula:

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[0076] Average shear stress τ ave is the equivalent shear stress prediction value τ obtained in the first embodiment. eq Corresponding to (Equation (9)), the average tangential resistance F t_ave is the predicted tangential resistance F obtained in the first embodiment. t_pre (Figure 2). Therefore, the average value of the shear stress τ ave may be called the equivalent shear stress prediction value, and the average tangential resistance F t_ave may be called the tangential resistance prediction.

[0077] Next, the advantageous effects of the second embodiment will be described. In the second embodiment, the average tangential resistance F is calculated using the formula (19). t_aveThe origin P shown in Figure 9 can be obtained. B0 The sliding of the working surface of the grinding wheel 54 against the workpiece 60 is taken into account in the range from the length L1 to the length L2. This allows the grinding phenomenon to be described in more detail.

[0078] The above-mentioned embodiments are merely examples, and it goes without saying that partial replacement or combination of the configurations shown in different embodiments is possible. Similar effects due to similar configurations of multiple embodiments are not mentioned in each embodiment. Furthermore, the present invention is not limited to the above-mentioned embodiments. For example, it will be obvious to those skilled in the art that various modifications, improvements, combinations, etc. are possible. [Explanation of symbols]

[0079] 10 Grinding machine 30 Grinding support device 31 Input section 32 Arithmetic section 33 Output section 34 Storage section 50 Bases 51 Table guide mechanism 52 Movable Table 53 Grindstone Head 54 Grindstone 55 Traverse direction guide rail 60 Work material

Claims

1. an input unit for inputting information specifying grinding conditions when cutting a workpiece with a cutting depth while rotating the grinding wheel and moving the workpiece relatively with respect to the grinding wheel, and information specifying physical property values ​​of the workpiece; a calculation unit that calculates a tangential resistance applied in a circumferential direction of a working surface of the grinding wheel based on information specifying the grinding conditions and physical property values ​​of the workpiece inputted to the input unit, and obtains a predicted tangential resistance value; an output unit that outputs information representing the predicted tangential resistance value calculated by the calculation unit; A grinding support device equipped with a grinding support device.

2. The calculation unit calculates a normal resistance applied in a normal direction of the working surface of the grindstone from the tangential resistance prediction value to obtain a normal resistance prediction value; The grinding support device according to claim 1 , wherein the output unit outputs the normal resistance prediction value calculated by the calculation unit.

3. The physical property values ​​of the workpiece input to the input unit include the tensile strength or shear strength and elongation of the workpiece, The calculation unit is determining an equivalent shear stress based on the tensile strength or shear strength value of the workpiece inputted to the input unit and the elongation value of the workpiece; From the grinding conditions, a shear area for shearing the workpiece during a period in which the grinding wheel rotates and the lowest point of the grinding wheel moves to the surface of the workpiece is calculated; 3. The grinding support device according to claim 1, wherein the predicted tangential resistance value is calculated by multiplying the equivalent shear stress by the shear area.

4. 4. The grinding support device according to claim 3, wherein the grinding conditions input to the input section include information representing a cutting depth of the grinding wheel, a grinding width, a diameter of the grinding wheel, a rotation speed of the grinding wheel, and a moving speed of the workpiece relative to the grinding wheel.

5. 5. The grinding support device according to claim 4, wherein the calculation unit calculates the shear cross-sectional area by multiplying the sum of a contact arc length, which is the circumferential length of the working surface of the grinding wheel from the lowest point of the grinding wheel to the surface of the workpiece, and a length that the workpiece moves relative to the grinding wheel during a period in which the grinding wheel rotates and the lowest point of the grinding wheel moves to the surface of the workpiece, by the grinding width.

6. a message prompting the user to input information specifying grinding conditions when the grinding wheel is rotated while cutting into the workpiece by a cutting depth and grinding the workpiece while moving the workpiece relatively to the grinding wheel, and information specifying physical property values ​​of the workpiece; A display device that displays information representing a predicted tangential resistance value obtained by calculating the tangential resistance applied in the circumferential direction of the working surface of the grinding wheel based on the input grinding conditions and information specifying the physical properties of the workpiece.

7. a function of acquiring information specifying grinding conditions and physical property values ​​of the workpiece when cutting the grinding wheel into the workpiece by a cutting depth while rotating the grinding wheel and moving the workpiece relatively to the grinding wheel to perform grinding; A function of calculating a predicted value of a tangential resistance applied in a circumferential direction of a working surface of the grinding wheel based on information specifying the grinding conditions and physical properties of the workpiece; A function of outputting the predicted value of the tangential resistance; A program that enables a computer to achieve the above.

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