Method for predicting the composite roughness curve of a workpiece, method for determining the material removal amount for plateau polishing, and apparatus for determining the material removal amount for plateau polishing.

Abstract

This invention provides a composite roughness curve prediction method that can predict the composite roughness curve of a plateau structure in which surface roughness is mixed between relatively flat plateau sections and valleys between those plateau sections. [Solution] In the composite roughness curve synthesis process S3-S4, based on the material removal amount φn of the plateau polishing process, peaks corresponding to the material removal amount φn are removed from the surface roughness curve Fr of the roughly ground workpiece 42, and a portion of the plateau roughness curve Ff is incorporated into the removed section Tc from the surface roughness curve Fr of the workpiece 42 where the height corresponding to the material removal amount φn has been removed, thereby synthesizing a composite roughness curve Fc. This makes it possible to predict the composite roughness curve Fc of a plateau structure in which surface roughness is mixed between relatively flat plateau sections P and valleys between those plateau sections P.

Description

Technical Field

[0001] The present invention relates to a composite roughness curve prediction method for predicting composite roughness of a ground surface having a composite roughness curve formed of flat plateau portions obtained by removing a predetermined stock removal through plateau grinding, i.e., plateau polishing with fine abrasive grains after rough grinding with coarse abrasive grains, and valley portions positioned between the plateau portions.

Background Art

[0002] It is desired to predict the composite roughness of a ground surface obtained through rough grinding and plateau polishing with a predetermined stock removal from the stock removal for the plateau polishing. This allows the stock removal for plateau polishing after rough grinding used to obtain a target composite roughness to be determined without performing complicated test grinding.

[0003] In contrast, Patent Document 1 discloses a method of calculating a total gradation from an image of a ground surface and estimating the surface roughness of the ground surface based on an actual total gradation from a correlation between the pre-obtained total gradation and surface roughness. In addition, Patent Document 2 discloses a method of estimating the surface roughness of a ground surface based on state data actually detected by a detector from a correlation between state data related to the surface roughness of the ground surface and the surface roughness measured by a small-diameter tracing stylus.

Prior Art Literature

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, for ground surfaces having a composite roughness curve with a plateau structure in which surface roughness is mixed between plateau sections with a predetermined amount of material removed by performing plateau polishing with fine abrasive grains after rough grinding with coarse abrasive grains, and valley sections located between the plateau sections, it was difficult to estimate the surface roughness using the techniques described in Patent Documents 1 and 2. Furthermore, there was no technology to estimate the composite roughness curve of such a plateau structure. Therefore, when grinding a workpiece so that its surface had a composite roughness curve of a plateau structure with target roughness parameters, it was necessary to repeatedly perform grinding and measure the composite roughness curve. Consequently, determining the amount of material to be removed by the plateau grinding wheel used in plateau polishing required considerable skill.

[0006] The present invention has been made against the above circumstances, and its objective is to provide a composite roughness curve prediction method that can predict the composite roughness curve of a plateau structure in which surface roughness is mixed between relatively flat plateau portions and valleys between plateau portions.

[0007] Based on the above circumstances, the inventors conducted various studies and found that by removing the peaks corresponding to the material removal amount by plateau polishing from the surface roughness curve obtained by rough grinding the surface of the workpiece using a rough grinding wheel, and then applying the plateau roughness curve formed on the surface of the workpiece by a plateau polishing wheel to the removed portion, a composite roughness curve of the workpiece can be synthesized. The present invention is based on this finding. [Means for solving the problem]

[0008] In other words, the gist of the first invention is a method for predicting the composite roughness curve of a workpiece, wherein (a) a plateau polishing process is performed on the grinding surface of a workpiece that has been roughly ground using a rough grinding wheel, and the plateau polishing process is performed using a plateau polishing wheel with finer grain than the rough grinding wheel, and the plateau polishing process is performed using a plateau polishing wheel with finer grain than the rough grinding wheel, and (b) a surface roughness curve storage step is performed to store in advance the surface roughness curve of the workpiece that has been roughly ground based on the grain size of the rough grinding wheel, and (c) the plateau polishing process is performed to store in advance the surface roughness curve of the workpiece that has been roughly ground using a rough grinding wheel, and (c) the plateau polishing process is performed (d) A plateau roughness curve storage step of pre-storing a plateau roughness curve formed on the surface of the workpiece by the plateau grinding wheel used in plateau grinding, and (d) a composite roughness curve synthesis step of removing the peaks of the surface roughness curve of the roughly ground workpiece at a height corresponding to the removal amount based on the removal amount of the plateau grinding, and incorporating a part of the plateau roughness curve into the removed section from the surface roughness curve of the workpiece at a height corresponding to the removal amount to synthesize the composite roughness curve.

[0009] The gist of the plateau polishing method of the second invention is to include a surface roughness parameter calculation step of calculating surface roughness parameters for each of the aforementioned material removal amounts from a load curve showing the ratio of the actual portion to the height direction of the composite roughness curve obtained in the first invention, and a material removal amount determination step of determining the material removal amount that satisfies the roughness standard based on whether or not any of the surface roughness parameters calculated in the surface roughness parameter calculation step satisfies the predetermined roughness standard.

[0010] The gist of the third invention's method for determining the material removal amount in plateau polishing is that, in the second invention, the surface roughness parameters are the height Rk of the core portion of the load curve, the average height Rpk of the protruding peaks above the core portion, the average depth Rvk of the protruding valleys below the core portion, the load length ratio Mr1 indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 indicating the boundary between the protruding valleys and the core portion.

[0011] The gist of the plateau polishing material removal determination device of the fourth invention is a plateau polishing material removal determination device that determines the amount of material removal for plateau polishing such that the plateau roughness curve obtained by plateau polishing satisfies a preset roughness standard when plateau polishing is performed on the ground surface of a workpiece that has been roughly ground using a rough grinding wheel, by limiting the height of the peaks among the peaks and valleys of the surface roughness curve of the ground surface, and the plateau polishing material removal device of plateau polishing satisfies a preset roughness standard, and includes: (b) a composite roughness curve synthesis unit that synthesizes composite roughness curves for each of a plurality of preset amounts of material removal; and (c) a material removal determination unit that calculates surface roughness parameters for each amount of material removal from a load curve that shows the ratio of the actual portion to the height direction of the composite roughness curve, and determines the amount of material removal that satisfies the preset roughness standard based on whether or not one of the calculated surface roughness parameters satisfies the preset roughness standard.

[0012] The gist of the plateau polishing amount determination device of the fifth invention is that, in the fourth invention, the composite roughness curve synthesis unit removes the peaks corresponding to the height of the material removal from the surface roughness curve of the roughly ground workpiece, and synthesizes the composite roughness curve by incorporating a part of the plateau roughness curve into the removed section from which the height corresponding to the material removal from the surface roughness curve of the workpiece has been removed.

[0013] The gist of the plateau polishing material removal device of the sixth invention is that, in the fourth invention, the surface roughness parameters are the height Rk of the core portion of the load curve, the average height Rpk of the protruding peaks above the core portion, the average depth Rvk of the protruding valleys below the core portion, the load length ratio Mr1 indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 indicating the boundary between the protruding valleys and the core portion. [Effects of the Invention]

[0014] According to the composite roughness curve prediction method for a workpiece of the first invention, in the composite roughness curve synthesis step, peaks corresponding to the material removal amount are removed from the surface roughness curve of the workpiece that has been roughly ground based on the material removal amount of the plateau grinding process, and a part of the plateau roughness curve is incorporated into the removed section from the surface roughness curve of the workpiece where the height corresponding to the material removal amount has been removed, thereby synthesizing a composite roughness curve. As a result, it is possible to predict the composite roughness curve of a plateau structure in which surface roughness is mixed between relatively flat plateau sections and valleys between those plateau sections.

[0015] According to the plateau polishing material removal method of the second invention, in the surface roughness parameter calculation step, surface roughness parameters are calculated for each material removal amount from a load curve that shows the ratio of the actual portion to the height direction of the composite roughness curve. In the material removal amount determination step, the material removal amount that satisfies the roughness standard is determined based on whether or not any of the calculated surface roughness parameters satisfies the preset roughness standard. As a result, there is no need to repeatedly perform grinding and measure the composite roughness curve, and the material removal amount for plateau polishing can be easily determined without requiring expertise.

[0016] According to the plateau polishing material removal method of the third invention, the surface roughness parameters are the height Rk of the core portion of the load curve, the average height Rpk of the protruding peaks above the core portion, the average depth Rvk of the protruding valleys below the core portion, the load length ratio Mr1 indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 indicating the boundary between the protruding valleys and the core portion. This allows for the accurate determination of the material removal amount for plateau polishing that satisfies the roughness standard.

[0017] The plateau polishing material removal device of the fourth invention includes a composite roughness curve synthesis unit that synthesizes composite roughness curves for each of a plurality of preset material removal amounts, and a material removal amount determination unit that calculates surface roughness parameters for each material removal amount from a load curve that shows the ratio of the actual portion to the height direction of the composite roughness curve, and determines a material removal amount that satisfies a preset roughness standard based on whether or not one of the calculated surface roughness parameters satisfies a preset roughness standard. As a result, the material removal amount for plateau polishing can be easily determined without requiring skilled personnel.

[0018] According to the plateau polishing material removal determination device of the fifth invention, the composite roughness curve synthesis unit removes peaks corresponding to the material removal height from the surface roughness curve of the roughly ground workpiece, and incorporates a portion of the plateau roughness curve into the removed section from the surface roughness curve of the workpiece to synthesize a composite roughness curve. This makes it possible to easily predict the composite roughness curve of a plateau structure in which surface roughness is mixed between relatively flat plateau sections and valleys between those plateau sections.

[0019] According to the plateau polishing material removal device of the sixth invention, the surface roughness parameters are the height Rk of the core portion of the load curve, the average height Rpk of the protruding peaks above the core portion, the average depth Rvk of the protruding valleys below the core portion, the load length ratio Mr1 indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 indicating the boundary between the protruding valleys and the core portion. This allows for the accurate determination of the material removal amount for plateau polishing that satisfies the roughness standard. [Brief explanation of the drawing]

[0020] [Figure 1] This figure shows an electronic control device that constitutes a plateau polishing material removal device according to one embodiment of the present invention. [Figure 2] Figure 1 shows an example of a curve indicating the surface roughness of a rough grinding process, which is pre-stored in the electronic control unit. [Figure 3] This figure shows the curve after removing a predetermined material removal allowance from the waveform representing the surface roughness of the rough grinding process shown in Figure 2. [Figure 4] It is a diagram showing a composite roughness curve synthesized by fitting a part of the waveform of FIG. 5 into the blank section of the curve of FIG. 3 [Figure 5] It is a diagram showing an example of a curve indicating the surface roughness of plateau polishing performed subsequent to the rough grinding of FIG. 2 [Figure 6] It is a diagram explaining a bearing curve representing the ratio of the solid portion of surface irregularities (bearing length ratio) in the height direction of the curve of FIG. 5, and the surface roughness parameters Rk, Rpk, Rvk, Mr1, and Mr2 obtained from said bearing curve [Figure 7] It is a diagram explaining honing [Figure 8] It is a diagram showing bearing curves obtained by the honing of FIG. 7 for each stock removal amount [Figure 9] It is a diagram table showing surface roughness parameters for each stock removal amount obtained by the honing of FIG. 7 [Figure 10] It is a graph showing the relationship between Rk, which is the core height of the bearing curve that is one of the surface roughness parameters in FIG. 9, and the stock removal amount [Figure 11] It is a graph showing the relationship between Rpk, which is the average peak height of protruding peaks of the bearing curve that is one of the surface roughness parameters in FIG. 9, and the stock removal amount [Figure 12] It is a graph showing the relationship between Rvk, which is the average depth of protruding valleys of the bearing curve that is one of the surface roughness parameters in FIG. 9, and the stock removal amount [Figure 13] It is a graph showing the relationship between Mr1, which is the bearing length ratio indicating the boundary between the protruding peaks and the core portion that is one of the surface roughness parameters in FIG. 9, and the stock removal amount [Figure 14] It is a graph showing the relationship between Mr2, which is the bearing length ratio indicating the boundary between the protruding valleys and the core portion that is one of the surface roughness parameters in FIG. 9, and the stock removal amount [Figure 15] It is a flowchart explaining the control operation of the electronic control device that constitutes the stock removal amount determination device for plateau polishing of FIG. 1 DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiment, the drawings have been simplified or modified as appropriate, and the dimensional ratios and shapes of each part are not necessarily depicted accurately. [Examples]

[0022] Figure 1 is a diagram illustrating the electronic control device 10 of this embodiment. The electronic control device 10 may, for example, when polishing the inner surface of a workpiece 42 in a honing grinding machine 40, perform plateau polishing on the inner surface of the workpiece 42 that has been roughly ground using a rough grinding wheel having abrasive grains with an average particle size of 0.05 mm. In such cases, plateau polishing may be performed using a plateau polishing wheel having finer grains than the rough grinding wheel, for example, with abrasive grains having an average diameter of 0.02 mm. The electronic control device 10 functions as a plateau polishing material removal amount determination device that determines the material removal amount φn (μm) for plateau polishing so that the composite roughness curve Fc obtained by plateau polishing satisfies a preset roughness standard. The electronic control unit 10 includes an arithmetic control unit 12 that includes a CPU, RAM, ROM, etc., an input device 14 for data input such as a keyboard, a data storage device 16 that stores data such as waveform data that has been determined in advance, and a display device 18 that displays calculation results such as the material removal amount φn for plateau polishing.

[0023] The data storage device 16 includes a roughness specification storage unit 20 that stores in advance the target roughness specification of the product to be polished, a surface roughness curve storage unit 22 that stores a pre-determined surface roughness curve Fr of the polished surface of the workpiece 42 using a rough grinding wheel, and a plateau roughness curve storage unit 24 that stores a pre-determined plateau roughness curve Ff of the polished surface of the workpiece 42 using a plateau polishing wheel.

[0024] The target roughness specification of the product to be polished, stored in the roughness specification storage unit 20, is, for example, a customer requirement or a product shipment specification, and is specified, for example, by the height Rk of the core portion of the load curve LC described later, the average height Rpk of the protruding peaks above the core portion, the average depth Rvk of the protruding valleys below the core portion, the load length ratio Mr1 indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 indicating the boundary between the protruding valleys and the core portion.

[0025] Figure 2 illustrates a pre-determined surface roughness curve Fr of the polished surface of a workpiece 42 that has been roughly ground using a rough grinding wheel having abrasive grains with an average particle size of 0.05 mm, as stored in the surface roughness curve memory unit 22. Figure 5 illustrates a pre-determined plateau roughness curve Ff of the polished surface of a workpiece 42 that has been ground using a plateau polishing wheel having abrasive grains with an average particle size of 0.02 mm, as stored in the plateau roughness curve memory unit 24.

[0026] The calculation control unit 12 functionally includes a composite roughness curve synthesis unit 26, a surface roughness parameter calculation unit 28, and a material removal amount determination unit 30.

[0027] The composite roughness curve synthesis unit 26 synthesizes composite roughness curves Fc from the surface roughness curve Fr of the roughly ground workpiece 42 for each of several preset material removal amounts φn. First, the composite roughness curve synthesis unit 26 removes peaks corresponding to the material removal amount φn from the surface roughness curve Fr of the roughly ground workpiece 42, obtaining a waveform having a removal section Tc where the peaks are cut, as shown in Figure 3. Next, the composite roughness curve synthesis unit 26 incorporates a portion of the plateau roughness curve Ff shown in Figure 5 into the removal section Tc from which the height corresponding to the material removal amount φn of the surface roughness curve Fr of the workpiece 42 has been removed, synthesizing the composite roughness curve Fc shown in Figure 4. In the composite roughness curve Fc, the portion in the removal section Tc into which a portion of the plateau roughness curve Ff is incorporated corresponds to the plateau section P.

[0028] As shown in Figure 6, the surface roughness parameter calculation unit 28 calculates a load curve LC, which is a curve that represents the ratio of the physical portion to the spatial portion of the irregularities in the height direction of the composite roughness curve Fc, in a two-dimensional coordinate system with an axis representing height (μm) and an axis representing the load length ratio (percentage of the physical portion) R (%). From this load curve LC, the unit calculates the height Rk (μm) of the core portion of the load curve LC, the average height Rpk (μm) of the protruding peaks above the core portion, the average depth Rvk (μm) of the protruding valleys below the core portion, the load length ratio Mr1 (%) indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 (%) indicating the boundary between the protruding valleys and the core portion, as surface roughness parameters for each material removal amount φn.

[0029] The material removal amount determination unit 30 determines the material removal amount φn for each material removal amount φn of the plateau polishing process that satisfies the target roughness standard stored in the roughness standard storage unit 20, from among the surface roughness parameters for each material removal amount φn, and displays it on the display device 18.

[0030] Figure 7 is a diagram illustrating the main parts of a honing grinding machine 40 used in a grinding test conducted by the inventors. In Figure 7, a spindle 48 to which a honing head 46, equipped with multiple honing wheels 44, is fixed is driven so that the honing head 46 is rotated around the central axis CL of the workpiece 42 and reciprocated in the direction of the central axis CL. The honing wheels 44 are mounted on the honing head 46 so as to slide against the inner circumferential surface of the workpiece 42 under predetermined conditions. For rough grinding, a rough grinding wheel (metal diamond grinding wheel) having abrasive grains with an average particle size of 0.05 mm is used for the honing wheel 44, and for plateau polishing, a plateau polishing wheel (metal diamond grinding wheel) having abrasive grains with an average particle size of 0.02 mm is used for the honing wheel 44.

[0031] (Grinding conditions) Processing machine: Honing grinding machine Grinding stone type: Metal diamond grinding stone (average abrasive grain size of 0.05 mm) Metal diamond grinding wheel (average abrasive particle size of 0.02 mm) Grinding wheel dimensions: 75mmL x 4mmW Number of whetstones: 8 Grinding wheel peripheral speed: 70.1 m / min Reciprocating speed: 24m / min Cutting speed: φ4μm / sec Sparkout: 0 sec Grinding fluid: water soluble Material of workpiece / ground surface: Gray cast iron / cylinder bore Inner diameter of the workpiece: 82mmφ Length of workpiece: 140mm

[0032] The inventors performed rough grinding and plateau polishing on the workpiece 42 using the above grinding conditions, and obtained a surface roughness curve Fr formed on the polished surface of the workpiece 42 that was roughly ground using a rough grinding wheel having abrasive grains with an average particle size of 0.05 mm, and a plateau roughness curve Ff formed on the polished surface of the workpiece 42 that was polished using a plateau polishing wheel having abrasive grains with an average particle size of 0.02 mm. Next, the peaks corresponding to the material removal amount φn were removed from the surface roughness curve Fr of the polished surface of the roughly ground workpiece 42, and a waveform having a removal section Tc in which the peaks were cut off was obtained as shown in Figure 3. Next, a part of the plateau roughness curve Ff shown in Figure 5 was incorporated into the removal section Tc from the surface roughness curve Fr of the workpiece 42 in which the height corresponding to the material removal amount φn was removed, and the composite roughness curve Fc shown in Figure 4 was synthesized. Then, the load curve LC of the composite roughness curve Fc was calculated, and from this load curve LC, the height Rk of the core portion of the load curve LC, the average height Rpk of the protruding peaks above the core portion, the average depth Rvk of the protruding valleys below the core portion, the load length ratio Mr1 indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 indicating the boundary between the protruding valleys and the core portion were calculated as surface roughness parameters for each material removal amount φ1 to φ10. The material removal amounts φ1 to φ10 are set, for example, in increments of 1 μm to several μm.

[0033] Figure 8 shows the load curves LC for material removal amounts φ1, φ3, φ5, and φ7. Figure 9 shows the surface roughness parameters for material removal amounts φ1 to φ10, Figure 10 shows the change in core height Rk of the load curve LC for material removal amounts φ1 to φ8, Figure 11 shows the change in average height Rpk of the protruding peaks for material removal amounts φ1 to φ8, Figure 12 shows the change in average depth Rvk of the protruding valleys for material removal amounts φ1 to φ8, Figure 13 shows the change in load length ratio Mr1, which indicates the boundary between the protruding peaks and the core, for material removal amounts φ1 to φ8, and Figure 14 shows the change in load length ratio Mr2, which indicates the boundary between the protruding valleys and the core, for material removal amounts φ1 to φ8.

[0034] Furthermore, when the target roughness specification is, for example, that the core height Rk≦2(μm) of the load curve LC, the average height Rpk≦0.7(μm) of the protruding peaks, the average depth Rvk≦1.5(μm) of the protruding valleys, the load length ratio Mr1≦10(%) indicating the boundary between the protruding peaks and the core, and the load length ratio Mr2≦85(%) indicating the boundary between the protruding valleys and the core, the inventors were able to determine the material removal amount φ7 as the material removal amount φn for plateau polishing from Figure 9.

[0035] Figure 15 is a flowchart illustrating the control operation of the electronic control device 10. In Figure 15, in step S1 (hereinafter, the step will be omitted) corresponding to the surface roughness curve memory process and the plateau roughness curve memory process, data of the surface roughness curve Fr and plateau roughness curve Ff for each particle size, which have been acquired in advance, are input. Next, in S2, corresponding to the roughness specification memory process, the target roughness specification for the target plateau structure is input. Then, S3 and S4, corresponding to the composite roughness curve synthesis unit 26 or the composite roughness curve synthesis process, are executed.

[0036] In S3, based on the material removal allowance φn of the plateau grinding process, peaks corresponding to the material removal allowance φn are removed from the surface roughness curve Fr of the roughly ground workpiece 42. In S4, a portion of the plateau roughness curve Ff is incorporated into the removal section Tc from which the height corresponding to the material removal allowance φn of the surface roughness curve Fr of the workpiece 42 has been removed, and a composite roughness curve Fc is synthesized.

[0037] Next, in the surface roughness parameter calculation unit 28 or S5, which corresponds to the surface roughness parameter calculation process, as shown in Figure 6, a load curve LC is calculated in a two-dimensional coordinate system with an axis indicating height (μm) and an axis indicating load length ratio (percentage of physical portion) R (%), which represents the ratio of the physical portion to the spatial portion of the irregularities in the height direction of the composite roughness curve Fc. From this load curve LC, the height Rk (μm) of the core portion of the load curve LC, the average height Rpk (μm) of the protruding peaks above the core portion, the average depth Rvk (μm) of the protruding valleys below the core portion, the load length ratio Mr1 (%) indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 (%) indicating the boundary between the protruding valleys and the core portion are calculated as surface roughness parameters for each removal amount φn.

[0038] Then, in the material removal amount determination unit 30 or in steps S6-S14 corresponding to the material removal amount determination process, for each material removal amount φn of the plateau polishing process, the material removal amount φn that satisfies the preset roughness standard stored in the roughness standard storage unit 20 from among the surface roughness parameters calculated from the load curve LC is determined as the material removal amount φn that satisfies the roughness standard and is displayed on the display device 18. Specifically, in S6, it is determined whether the height Rk of the core portion of the load curve LC is less than or equal to its roughness standard of 2 (μm); in S7, it is determined whether the average height Rpk of the protruding peaks is less than or equal to its roughness standard of 0.7 (μm); in S8, it is determined whether the average depth Rvk of the protruding valleys is less than or equal to its roughness standard of 1.5 (μm); in S9, it is determined whether the load length ratio Mr1 indicating the boundary between the protruding peaks and the core portion is less than or equal to its roughness standard of 10 (%); and in S10, it is determined whether the load length ratio Mr2 indicating the boundary between the protruding valleys and the core portion is less than or equal to its roughness standard of 85 (%). If any of the judgments in S6-S10 are negative, the material removal amount φn and particle size are changed in S13, and then steps S3 and below are repeated. However, if any of the judgments in S6-S10 are positive, it is determined in S12 whether all combinations have been completed. If the judgment in S12 is denied, steps S13 and S3 onwards are repeated. However, if the judgment in S12 is affirmed, in S14, the amount of material removed φn that satisfies the roughness standard is determined as the amount of material removed φn for plateau polishing and is displayed on the display device 18.

[0039] According to the composite roughness curve prediction method for the workpiece 42 of this embodiment, in the composite roughness curve synthesis step (S3-S4), based on the material removal amount φn of the plateau grinding process, peaks corresponding to the height of the material removal amount φn are removed from the surface roughness curve Fr of the roughly ground workpiece 42, and a portion of the plateau roughness curve Ff is incorporated into the removed section Tc from the surface roughness curve Fr of the workpiece 42 where the height corresponding to the material removal amount φn has been removed, thereby synthesizing a composite roughness curve Fc. This makes it possible to predict the composite roughness curve Fc of a plateau structure in which surface roughness is mixed between relatively flat plateau sections P and valleys between those plateau sections P.

[0040] Furthermore, according to the plateau polishing material removal method of this embodiment, in the surface roughness parameter calculation step (S5), surface roughness parameters are calculated for each material removal amount φn from the load curve LC, which shows the ratio of the actual material to the height direction of the composite roughness curve Fc. In the material removal amount determination step (S6-S14), the material removal amount φn that satisfies the roughness standard is determined based on whether or not any of the calculated surface roughness parameters satisfies the preset roughness standard. As a result, there is no need to repeatedly perform grinding and measure the composite roughness curve Fc, and the material removal amount φn for plateau polishing that satisfies the roughness standard can be easily determined without requiring any special skills.

[0041] Furthermore, according to the plateau polishing material removal method of this embodiment, the surface roughness parameters are the height Rk of the core portion of the load curve LC, the average height Rpk of the protruding peaks above the core portion, the average depth Rvk of the protruding valleys below the core portion, the load length ratio Mr1 indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 indicating the boundary between the protruding valleys and the core portion. This allows for the accurate determination of the material removal amount φn for plateau polishing that satisfies the roughness standard.

[0042] Furthermore, the electronic control device (plateau polishing material removal determination device) 10 of this embodiment includes a composite roughness curve synthesis unit 26 that synthesizes composite roughness curves Fc for each of several preset material removal amounts φn, and a material removal determination unit 30 that calculates surface roughness parameters from load curves LC that show the ratio of the actual material portion to the height direction of the composite roughness curve Fc for each material removal amount φn, and determines a material removal amount φn that satisfies the roughness standard based on whether or not one of the calculated surface roughness parameters satisfies the preset roughness standard. As a result, a material removal amount φn that satisfies the roughness standard for plateau polishing can be easily determined without requiring any special skills.

[0043] Furthermore, according to the electronic control device (plateau polishing material removal amount determination device) 10 of this embodiment, the composite roughness curve synthesis unit 26 removes peaks corresponding to the material removal amount φn from the surface roughness curve Fr of the roughly ground workpiece 42, and incorporates a portion of the plateau roughness curve Ff into the removed section Tc from the surface roughness curve Fr of the workpiece 42 where the height corresponding to the material removal amount φn has been removed, thereby synthesizing a composite roughness curve Fc. This makes it easy to predict the composite roughness curve Fc of a plateau structure in which surface roughness is mixed between relatively flat plateau sections P and the valleys between those plateau sections P.

[0044] Furthermore, according to the electronic control device (plateau polishing material removal device) 10 of this embodiment, the surface roughness parameters are the height Rk of the core portion of the load curve LC, the average height Rpk of the protruding peaks above the core portion, the average depth Rvk of the protruding valleys below the core portion, the load length ratio Mr1 indicating the boundary between the protruding peaks and the core portion, and the load length ratio Mr2 indicating the boundary between the protruding valleys and the core portion. This allows for the accurate determination of the material removal amount φn for plateau polishing that satisfies the roughness standard.

[0045] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the present invention is not limited to this embodiment and can be implemented in other forms.

[0046] For example, the polishing of the composite roughness curve Fc of the plateau structure in the above-described embodiment may be any of the following: polishing of the inner surface of the workpiece 42, polishing of the outer surface of the workpiece 42, or polishing of the flat surface of the workpiece 42.

[0047] Furthermore, the aforementioned method for predicting the composite roughness curve of the workpiece 42, the method for determining the material removal amount in plateau grinding, and the apparatus for determining the material removal amount in plateau grinding can also be applied to superfinishing processes in which a superfinishing grinding wheel applied to the outer surface of a cylindrical workpiece 42 is reciprocated in a direction parallel to the central axis CL of the cylindrical workpiece 42.

[0048] It should be noted that the above is merely one embodiment, and although other examples are not provided, the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art, without departing from its spirit. [Explanation of Symbols]

[0049] 10: Electronic control device (device for determining the amount of material removed during plateau polishing) 26: Composite roughness curve synthesis section 30: Determination of Payment 42: Work material Fr: Surface roughness curve Ff: Plateau roughness curve Fc: Composite roughness curve LC: Load curve φn: amount Tc: Removal section P: Plateau R: Load length ratio (the ratio of the solid portion to the height direction of the composite roughness curve) S1: Surface roughness curve memory process, plateau roughness curve memory process S3-S4: Composite roughness curve synthesis process S5: Surface roughness parameter calculation process S6-S14: Machining allowance determination process Rk: Height of the core of the load curve Rpk: Average height of the protruding peak Rvk: Average depth of the protruding valley Mr1: Load length ratio indicating the boundary between the protruding peak and the core. Mr2: Load length ratio indicating the boundary between the protruding valley and the core.

Claims

1. A method for predicting the composite roughness curve of a workpiece, wherein plateau polishing is performed on the grinding surface of a workpiece that has been roughly ground using a coarse grinding wheel, and plateau polishing is performed using a plateau polishing wheel with finer grain than the coarse grinding wheel, thereby predicting the composite roughness curve of the workpiece, wherein plateau polishing is performed on the grinding surface of the workpiece that has been roughly ground using a coarse grinding wheel, and plateau polishing is performed on the plateau polishing wheel with finer grain than the coarse grinding wheel, A surface roughness curve storage step, which stores in advance the surface roughness curve of the workpiece that has been roughly ground based on the grit size of the rough grinding wheel, A plateau roughness curve memory step is performed to pre-store the plateau roughness curve formed on the surface of the workpiece by the plateau polishing wheel used in the plateau polishing process, The process includes a composite roughness curve synthesis step, in which, based on the amount of material removed by the plateau grinding process, the peaks corresponding to the height of the material removed are removed from the surface roughness curve of the roughly ground workpiece, and a portion of the plateau roughness curve is incorporated into the removed section of the surface roughness curve of the workpiece to synthesize the composite roughness curve. A method for predicting the composite roughness curve of a workpiece, characterized by the features described above.

2. A surface roughness parameter calculation step of calculating surface roughness parameters for each of the material removal amounts from a load curve showing the ratio of the actual portion to the height direction of the composite roughness curve obtained by the composite roughness curve prediction method of the workpiece according to claim 1, The process includes determining the amount of material to be removed that satisfies the roughness standard, based on whether or not any of the surface roughness parameters calculated in the surface roughness parameter calculation process satisfies the predetermined roughness standard. A method for determining the material removal amount in plateau polishing according to feature 1.

3. The surface roughness parameters are: Rk, the height of the core portion of the load curve; Rpk, the average height of the protruding peaks above the core portion; Rvk, the average depth of the protruding valleys below the core portion; Mr1, the load length ratio indicating the boundary between the protruding peaks and the core portion; and Mr2, the load length ratio indicating the boundary between the protruding valleys and the core portion. The method for determining the material removal amount in plateau polishing according to feature 2.

4. A plateau polishing device for determining the amount of material removed during plateau polishing, which is performed on the ground surface of a workpiece that has been roughly ground using a coarse grinding wheel, by applying plateau polishing with a finer-grained plateau polishing wheel than the coarse grinding wheel, to provide a plateau portion in which the height of the peak portion of the peak portion of the surface roughness curve of the ground surface is limited. The device determines the amount of material removed during plateau polishing so that the plateau roughness curve obtained by the plateau polishing satisfies a preset roughness standard. A composite roughness curve synthesis unit that synthesizes composite roughness curves for each of the pre-set multiple types of material removal amounts, Includes a removal amount determination unit that calculates a surface roughness parameter for each removal amount from a load curve showing the ratio of the material portion to the height direction of the composite roughness curve, and determines the removal amount that satisfies the roughness standard based on whether or not any of the calculated surface roughness parameters satisfies the predetermined roughness standard. A plateau polishing process material removal device characterized by the following features.

5. The composite roughness curve synthesis unit removes the peaks corresponding to the material removal amount from the surface roughness curve of the roughly ground workpiece, and incorporates a portion of the plateau roughness curve into the removed section from the surface roughness curve of the workpiece where the height corresponding to the material removal amount has been removed, thereby synthesizing the composite roughness curve. The plateau polishing material removal device according to feature 4.

6. The surface roughness parameters are: Rk, the height of the core portion of the load curve; Rpk, the average height of the protruding peaks above the core portion; Rvk, the average depth of the protruding valleys below the core portion; Mr1, the load length ratio indicating the boundary between the protruding peaks and the core portion; and Mr2, the load length ratio indicating the boundary between the protruding valleys and the core portion. The plateau polishing material removal device according to feature 4.

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