Method for converting jet cutting speed distribution into data, numerical simulator using data of jet cutting speed distribution, and air blast numerically controlled machining apparatus including numerical simulator

Abstract

To provide a method for digitizing a cutting speed distribution of a jet flow which is a distribution of a cutting speed of a surface to be machined by the jet flow in air blast machining for jetting the jet flow including compressed air and abrasive grains from a nozzle in a vertically downward direction to the surface to be machined perpendicular to a central axis of the nozzle.SOLUTION: In the data-making method of the cutting speed distribution of the jet, the cutting speed distribution of the jet is formulated as the following expression 1 by using the expression of Gaussian distribution, and the cutting speed distribution of the jet is made into data by coefficients A and σ in the expression 1. In Equation 1, dZ / dt is a height (axial coordinate) in a cylindrical axis direction in a cylindrical coordinate system (r, θ, dZ / dt) having the central axis of the nozzle as a cylindrical axis. In Equation 1, r is a moving radius (axial distance) in the cylindrical coordinate system (r, θ, dZ / dt). In Equation 1, t is time.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technology for facilitating the simulation of air blast processing, such as when using air blast to carve the surface of a brittle material such as ceramic or glass into an arbitrary shape, or when grinding an uneven surface to a flat surface. [Background technology]

[0002] Conventionally, a gliding center (machining center) capable of NC (numerically controlled) cutting has been used to automatically cut the surface of brittle materials such as ceramics and glass into any desired shape.

[0003] However, since the gliding center grinds by bringing the cutting tool into contact with the surface of the workpiece, care must be taken because if the force pressing the cutting tool exceeds a limit value, cracks will occur on the surface of the workpiece, and it is not necessarily an efficient processing method.

[0004] In contrast, air blasting involves spraying abrasive grains (abrasive material) along with compressed air from a nozzle to scrape the surface of the workpiece, so there is no risk of cracks occurring due to excessive pressure from the cutting tool as described above.

[0005] Here, Patent Document 1 discloses a processing method and processing device for performing NC cutting using air blasting.

[0006] Patent Document 1 describes a processing method for processing a semiconductor wafer having an inconstant thickness to a uniform thickness, and a processing apparatus 90 for carrying out the processing method. As shown in Fig. 16, the processing apparatus 90 includes a processing tool 93 having a nozzle 93a that discharges abrasive grains together with compressed air onto the processing surface of the wafer 91 in order to reduce the thickness of the wafer 91, a movement mechanism 94 that moves the nozzle 93a to change the position of the nozzle 93a relative to the processing surface of the wafer 91, and a control unit 95 that controls the movement mechanism 94 and / or the discharge amount of the abrasive grains based on information about the processing speed of the wafer 91 by the abrasive grains discharged from the nozzle 93a and information about the thickness distribution of the wafer.

[0007] The wafer processing speed information is acquired by measuring the processing speed of the processing tool 93 on the wafer 91 through experiments or the like in advance.

[0008] The thickness distribution information of the wafer is obtained by measuring the coordinates of a plurality of positions on the surface of the wafer 91 in a plan view and the thickness of the wafer 91 at each of the plurality of positions. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-207935 Summary of the Invention [Problem to be solved by the invention]

[0010] As described above, the processing method and processing apparatus 90 described in Patent Document 1 performs processing by controlling the movement direction and movement speed of the nozzle 93a and the amount of abrasive grains sprayed from the nozzle 93a based on the above-mentioned wafer processing speed information and wafer thickness distribution information.

[0011] However, with regard to the processing speed information of the wafer, Patent Document 1 only states that, for example, the processing speed of the wafer is measured by changing the material of the wafer 91, the material of the abrasive grains, the amount of abrasive grains discharged, the discharge speed, etc. through advance experiments, etc., and the results are used. However, it does not specifically state how the processing speed information of the wafer is archived (stored as data), or what means are used to determine the direction and speed of movement of the nozzle 93a and the amount of abrasive grains to be sprayed from the processing speed information of the wafer and the thickness information of the wafer.

[0012] In air blasting, in which a jet containing compressed air and abrasive grains is sprayed vertically downward from a nozzle onto a workpiece surface perpendicular to the central axis of the nozzle, the speed at which the workpiece surface is cut (the cutting speed of the jet) is fastest for the jet flowing along the central axis of the nozzle, as shown in Figure 1, and the cutting speed of the jet slows as it moves away from the central axis of the nozzle in the radial direction (r in the figure).

[0013] However, the distribution of the cutting speed of the jet (jet cutting speed distribution) mentioned above varies depending on the processing conditions of the air blast, such as the material of the workpiece, the nozzle, the abrasive (type and dimensions), the amount of spray, the spray pressure, and the distance between the nozzle tip and the workpiece surface.

[0014] Here, when using cutting tools to carve out arbitrary curved surfaces, it is useful to prepare tools with blades of various sizes and shapes and use them appropriately.When using air blasting, it is also necessary to create a system that can select data on the cutting speed distribution of various jets at any time.

[0015] In view of the above, it is desirable to investigate in advance the relationship between the processing conditions of the air blast and the cutting speed distribution of the jet, and to establish a system for efficiently archiving the obtained data.

[0016] Furthermore, the shape of the cutting surface of the workpiece formed by air blasting is determined by a combination of the cutting speed distribution of the jet and the movement conditions of the nozzle that sprays it (e.g., movement path, movement speed, overlapping of the movement paths, etc.), and if the cutting speed distribution of the jet does not have a simple shape, there is a problem that the shape of the cutting surface cannot be easily predicted (calculated).

[0017] Therefore, a simple and efficient method for obtaining data on the cutting velocity distribution of the jet is desired.

[0018] At the same time, it is also desirable to develop a means (numerical simulator) for calculating the shape of the cutting surface formed on the workpiece surface from data on the cutting speed distribution of a specified jet and the specified movement conditions of the nozzle.

[0019] The present invention has been made in consideration of the above, and aims to provide a method for converting the cutting speed distribution of a jet into data, a numerical simulator that utilizes the data on the cutting speed distribution of the jet, and an air blast numerically controlled processing device equipped with the numerical simulator. [Means for solving the problem]

[0020] The means for solving the problems are described below together with the reference numerals used in the description of the embodiment of the invention. These reference numerals are used to clarify the correspondence between the description of the claims and the description of the embodiment of the invention, and needless to say, are not used to restrict the interpretation of the technical scope of the present invention.

[0021] In order to achieve the above-mentioned object, the method of the present invention for converting the cutting speed distribution of a jet into data is characterized in that, in air blast processing in which a jet containing compressed air and abrasive grains is sprayed vertically downward from a nozzle onto a workpiece surface perpendicular to the central axis of the nozzle, the cutting speed distribution of the jet, which is the distribution of the speed at which the workpiece surface is cut by the jet, is formulated using the Gaussian distribution equation as shown in the following equation 1, and the cutting speed distribution of the jet is converted into data using the coefficients A and σ in equation 1 (Claim 1).

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[0022] In Equation 1, dZ / dt is the height in the cylindrical axial direction (axial coordinate) in a cylindrical coordinate system (r, θ, dZ / dt) in which the central axis of the nozzle is the cylindrical axis. r in Equation 1 is the radius (axial distance) in the cylindrical coordinate system (r, θ, dZ / dt). t in Equation 1 is time.

[0023] Next, the method of measuring the coefficients A and σ in Equation 1 of the present invention is as follows: the feed direction of the nozzle that sprays a jet containing compressed air and abrasive grains in a vertically downward direction is defined as the x direction, and the vertically downward direction is defined as the z direction; and then, after setting an orthogonal coordinate system (x, y, z) so that the xy plane of the origin overlaps with the work surface that is perpendicular to the central axis of the nozzle, The nozzle is moved from an initial position where the jet of water ejected from the nozzle does not hit the work surface, and the nozzle is moved over the work surface while ejecting the jet of water while keeping the distance between the work surface and the nozzle constant, at a feed speed of v f A cutting groove is formed on the workpiece surface by a feed process (see Figure 3) in which the center of the nozzle passes on a straight line (0, μ, 0) and the nozzle is moved to a position where the jet does not hit the workpiece surface, and the outline of a cross section (yz plane) perpendicular to the feed direction (x direction) of the nozzle is measured for the cutting groove, The measurement result of the contour is approximated to the following formula 2, and the coefficients A and σ are obtained from the formula 2 (claim 2).

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[0024] Next, the method of correcting the cutting speed distribution of the jet of the present invention is to use the correction function C f The method is characterized in that it is corrected as shown in Equation 3 by (claim 3).

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[0025] In addition, when air blasting the center of a truncated cone-shaped recess (see Figure 4), the correction function C in Equation 3 f is axially symmetric and is a function of at least the r coordinate, the height of the wall obstructing the air flow (the height of the truncated cone) wh, and the distance to the wall wr1 (the radius of the upper base surface), wr2 (the radius of the lower base surface), etc., and is expressed by the following equation 4 (Claim 4). C f =C f (r,wh,wr1,wr2,...)...(Equation 4)

[0026] In addition, when air blasting a part with a wall on one side (see Figure 5), the correction function C in Eq. f is a function of at least the r coordinate, the θ coordinate, the height wh of the wall that obstructs the air flow, and the distance wd to the wall, and may be expressed by the following equation 5 (claim 5). C f =C f (r,θ,wh,wd...)...(Equation 5)

[0027] Next, the numerical simulator of the present invention, which utilizes data on the cutting speed distribution of a jet, is characterized in that in air blast processing, in which a jet containing compressed air and abrasive grains is sprayed vertically downward from a nozzle onto a workpiece surface perpendicular to the central axis of the nozzle, the cutting speed distribution of the jet, which is the distribution of the speed at which the workpiece surface is cut by the jet, is fitted to an equation that uses a Gaussian distribution and can be converted into data using two coefficients in the equation (e.g., coefficients A and σ in equation 1), and using this equation, calculates and outputs (simulates) the shape of the cutting surface formed on the workpiece surface when the nozzle is moved under specified movement conditions (e.g., movement path, movement speed, overlapping of movement paths, etc.) (Claim 6).

[0028] Furthermore, the numerical simulator may have a function of applying the cutting speed distribution of the jet to Equation 1 and archiving the relationship between the air blast processing conditions (e.g., workpiece material, nozzle diameter, abrasive (type and dimensions), spray amount, spray pressure, distance from the workpiece surface, etc.) previously investigated through experiments and the cutting speed distribution digitized by the two coefficients A and σ in Equation 1 (Claim 7).

[0029] Furthermore, the above-mentioned numerical simulator may be equipped with AI, and the AI ​​may be used to derive data on the cutting speed distribution of the jet and the movement conditions of the nozzle for machining the work surface into the desired shape, or to derive the machining conditions of the air blast and the movement conditions of the nozzle (claims 8 and 9).

[0030] Next, the air blast numerically controlled processing device of the present invention is equipped with a nozzle for injecting abrasive grains and a movement mechanism for moving the nozzle, as well as the above-mentioned numerical simulator (claim 10). [Effects of the Invention]

[0031] With the configuration of the present invention described above, the cutting speed distribution of the jet can be approximated to a Gaussian distribution and formulated as Equation 1, making it possible to digitize the cutting speed distribution of the jet simply by manipulating the numerical values ​​of the two coefficients A and σ in the equation.

[0032] Furthermore, in the method of measuring the coefficients A and σ using Equation 2, the jet containing compressed air and abrasive grains ejected from the nozzle is ejected at a location where the jet will not hit the workpiece surface until the jet stabilizes, and after the jet stabilizes, a feed process (see Figure 3) is performed in which the nozzle is moved at a constant speed over the workpiece surface to a position where the jet will not hit the workpiece surface, and the cross-sectional curve that crosses the cutting groove formed by the process can be measured, thereby making it possible to determine the coefficients A and σ more easily and accurately.

[0033] Furthermore, the above-mentioned numerical simulator of the present invention can calculate and output the shape of the cut surface formed on the workpiece surface by air blasting by specifying a specific jet cutting speed distribution and specific movement conditions. Furthermore, a numerical simulator having a function for archiving the relationship between the air blasting processing conditions and the cutting speed distribution converted into data by the two coefficients A and σ in Equation 1 can calculate and output the shape of the cut surface formed on the workpiece surface by air blasting by selecting the air blasting processing conditions from the archive and specifying the nozzle movement conditions.

[0034] Furthermore, a numerical simulator equipped with AI can reduce the enormous amount of time and effort required for simulation work, even when the desired cutting surface has a complex shape. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 4 is a reference diagram for explaining the speed at which the work surface is cut by a jet of compressed air and abrasive grains ejected from a nozzle. [Figure 2] A graph of Equation 1. [Figure 3] FIG. 1 is a diagram for explaining a method for measuring the coefficients A and σ in Equation 1. [Figure 4] FIG. 10 is a reference diagram for explaining a method of correcting Equation 1 when the center of a truncated cone-shaped depression is subjected to air blasting. [Figure 5] This is a reference diagram to explain how to correct Equation 1 when air blasting a location with a wall on one side. [Figure 6] 3A and 3B are diagrams showing cutting grooves formed on a workpiece surface in an embodiment of the present invention. [Figure 7] 6 shows the results of measuring the cross-sectional curve crossing the cutting groove using a stylus roughness meter in an embodiment of the present invention (FIG. 6), and the Gaussian curve that best matches the measurement results. [Figure 8] FIG. 10 is a diagram illustrating a method for measuring the coefficients A and σ in Equation 2 in [Simulation Example 1]. [Figure 9]FIG. 10 is a diagram showing the nozzle feed rate in [Simulation Example 1]. [Figure 10] FIG. 10 is a diagram showing the results of a simulation in [Simulation Example 1]. [Figure 11] FIG. 10 is another diagram showing the results of the simulation in [Simulation Example 1]. [Figure 12] FIG. 10 is a diagram explaining the simulation conditions in [Simulation Example 2]. [Figure 13] A figure showing the results of a simulation in [Simulation Example 2] where feed processing is repeated at intervals of s = 2·σ = 5.52. [Figure 14] 10 is a diagram showing the results of a simulation in which feed processing is repeated at intervals s=σ=2.76 in [Simulation Example 2]. [Figure 15] A figure showing the results of a simulation in [Simulation Example 2] where feed processing is repeated at intervals of s = 1 / 2 · σ = 1.38. [Figure 16] FIG. 1 is a diagram showing a conventional processing device that performs NC cutting using air blasting. DETAILED DESCRIPTION OF THE INVENTION

[0036] The present invention will now be described with reference to the accompanying drawings.

[0037] [Method for capturing data on the cutting speed distribution of the jet] In air blasting, when a jet containing compressed air and abrasive grains is sprayed vertically downward from a nozzle toward a work surface that is perpendicular to the central axis of the nozzle, the work surface is cut and dug in the cutting depth direction, and as described above with reference to Figure 1, the cutting speed of the jet is greatest below the central axis of the nozzle and decreases as it moves away from that axis in the radial direction (r in the figure).

[0038] After careful consideration of this phenomenon, the inventor discovered that the jet cutting speed distribution, which is the distribution of the speed at which the workpiece surface is cut by the jet, can be formulated using the Gaussian distribution (normal distribution) equation as follows, and can be converted into data using two coefficients A and σ.

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[0039] Here, dZ / dt in Equation 1 is the height in the cylindrical axial direction (axial coordinate) in a cylindrical coordinate system (r, θ, dZ / dt) in which the central axis of the nozzle (i.e., passing through the center of the jet and perpendicular to the workpiece surface) is the cylindrical axis. r in Equation 1 is the radius (axial distance) in the cylindrical coordinate system (r, θ, dZ / dt). t in Equation 1 is time.

[0040] Equation 1 means that the distribution of cutting speed (dZ / dt) is formulated by a rotating body (see Figure 2) created by doubling a Gaussian distribution with its median (center) at the central axis of the jet (central axis of the nozzle) in the direction of the dZ / dt axis (cylinder axis) and rotating it around the central axis of the jet.

[0041] Furthermore, the coefficient A in Equation 1 is the magnification of the Gaussian distribution in the dZ / dt axis direction, and the coefficient σ corresponds to the standard deviation of the Gaussian distribution.

[0042] The jet cutting speed distribution varies depending on the combination of various air blast processing conditions, such as the workpiece material, nozzle diameter, abrasive (type and dimensions), spray amount, spray pressure, distance from the workpiece surface, and nozzle feed speed, and an infinite number of air blast processing conditions can be set. Considering an air blast device that cuts the workpiece surface into an arbitrary shape, it would be desirable to store the relationships between as many jet cutting speed distributions and the air blast processing conditions as possible, and to be able to search for the air blast processing conditions that result in the optimal jet cutting speed distribution for the desired cutting shape. However, to achieve this, it is necessary to efficiently digitize the jet cutting speed distribution.

[0043] Therefore, it is useful to find that the cutting velocity distribution of the jet can be formulated by approximating it to a Gaussian distribution, as in Equation 1. In other words, the cutting velocity distribution of the jet can be quantified simply by manipulating the values ​​of the two coefficients A and σ.

[0044] [Method for measuring coefficients A and σ] The measurement method for determining the coefficients A and σ in Equation 1 will be explained.

[0045] As an example, in the above-mentioned air blasting process, the cross-sectional contour of the cutting groove formed by feeding the nozzle at a constant speed while maintaining a constant distance between the workpiece surface and the nozzle on the workpiece surface (cutting process by air blasting) is measured, and the coefficients A and σ in the following equation (Equation 2) are calculated.

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[0046] In detail, as shown in Figure 3, the feed direction of the nozzle that sprays a jet containing compressed air and abrasive grains in a vertically downward direction is the x direction, and the vertically downward direction (cutting depth direction) is the z direction, and an orthogonal coordinate system (x, y, z) is set so that the xy plane of the origin overlaps with the work surface that is perpendicular to the central axis of the nozzle. Then, while keeping the distance between the work surface and the nozzle constant, the nozzle sprays the jet over the work surface at a nozzle feed speed v f A cutting groove is formed on the workpiece surface by a feed process (see Figure 3) in which the center of the nozzle passes through a straight line y = μ(0, μ, 0) parallel to the x-axis while keeping the value constant, and the equation Z = Z(y) is derived to give the outline (cutting depth distribution) of the cross section (yz plane) perpendicular to the nozzle feed direction (x direction) for this cutting groove.

[0047] Here, in the above, the cutting speed distribution of the jet was expressed in the cylindrical coordinate system (r, θ, dZ / dt) as Equation 1, but if Equation 1 is rewritten in the Cartesian coordinate system (x, y, dZ / dt), the following equation is obtained.

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[0048] Here, when the nozzle is at x=ξ, y=μ, it is further given by the following equation:

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[0049] When the nozzle moves on a straight line parallel to the x-axis and passing through y = μ, the value of ξ in equation A2 changes as the nozzle moves.

[0050] Here, for any yz plane, x=x a Considering the yz plane passing through, the cutting speed distribution on this plane is further given by the following equation:

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[0051] Here, the right-hand side of equation A3 is a function of ξ and y, so we set dZ / dt=f(ξ, y).

[0052] And the velocity v f If we consider that the cutting speed distribution is dZ / dt during the short time Δt when the nozzle moves Δξ, the amount of cutting ΔZ of this plane is calculated by the above dZ / dt=f(ξ,y) and the short time Δt and speed v f From the relational expression (Equation A4) between the distance Δξ, it is expressed by the following equation (Equation A5).

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[0053] Therefore, the nozzle moves from infinity and x=x a The cutting depth distribution Z(y) of the plane (yz plane) formed when the cutting edge passes through and runs to infinity can be calculated from equation A4 as follows:

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[0054] Here, for the part in the form of a normalized Gaussian integral in Equation A6,

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[0055] Furthermore, the value of the left side of equation A7 is 0.997 when x is 3σ, and 0.99994 when x is 4σ, rapidly approaching 1. Therefore, even if the nozzle is not moved from infinity to process all the way to infinity, it can be considered to be approximately 1 as long as it is about 4σ away.

[0056] Therefore, when the nozzle is moved from a position sufficiently far away from the surface to be processed and processing continues until it is sufficiently far away, the following equation (Equation 2) can be written. Note that the sufficiently far distance is mathematically about 4σ, but physically it can be thought of as a distance where the jet does not directly hit the surface.

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[0057] As mentioned above, the above equation (2) expresses the cutting speed distribution given by equation (1) when the jet is moved in a direction parallel to the x-axis at a constant velocity v f This is the result of deriving the cutting amount (the outline of the groove to be cut in the yz cross section) when cutting with feed.

[0058] In addition to the method of measuring the coefficients A and σ using the above-mentioned formula 2, there is also a method of measuring the coefficients A and σ using the following formula 6, which is obtained by integrating both sides of formula 1, but this measurement method requires some ingenuity.

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[0059] The jet of compressed air and abrasive grains ejected from the nozzle requires several seconds from the start of ejection until the cutting force stabilizes. Therefore, when measuring the coefficients A and σ using Equation 6, an opening and closing device must be prepared and placed between the nozzle and the workpiece surface, and the device must be kept closed until the jet stabilizes. Once the jet stabilizes, the device must be quickly opened and left in that state for a specified time Δt, and after the time Δt has elapsed, the device must be quickly closed to complete the process.

[0060] Then, the cross-sectional curve passing through the center of the cutting surface (circular area in plan view) formed on the workpiece surface by the above-mentioned processing must be measured, but it is not easy to measure it so that it passes exactly through the center (the center of the circle in plan view).

[0061] In contrast, when measuring the coefficients A and σ using Equation 2, the jet is sprayed at a location where it will not hit the workpiece surface until the jet stabilizes, and then, after the jet stabilizes, a feed process (see Figure 3) is performed in which the nozzle is moved at a constant speed over the workpiece surface to a position where the jet will not hit the workpiece surface, and the cross-sectional curve that crosses the cutting groove formed by the process is measured, which makes it possible to determine the coefficients A and σ more easily and accurately.

[0062] [Method for correcting the cutting speed distribution of the jet] When there is an object obstructing the air flow near the workpiece surface, the pressure at which the jet containing compressed air and abrasive particles ejected from the nozzle collides with the workpiece surface is affected by the object obstructing the air flow, and the cutting speed distribution of the jet also changes.

[0063] In more detail, when the jet collides with the workpiece surface, it changes direction almost vertically and flows radially along the workpiece surface before being discharged. If there is something blocking this flow near the workpiece, the pressure at which the jet collides with the workpiece surface will be affected, and the cutting speed distribution will also change.

[0064] Therefore, as a method for correcting this change in cutting speed distribution, the change in cutting speed distribution is corrected by the correction function C fBy modifying it as in the following equation 3, a more accurate cutting speed distribution can be obtained.

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[0065] For example, as shown in Figure 4, when air blasting the center of a truncated cone-shaped recess, the wall blocking the air is at approximately the same distance from the central axis of the nozzle over 360°. In this case, the correction function C f is axially symmetric and is a function of at least the r coordinate, the height wh of the wall, and the distances to the wall wr1 (the radius of the upper base surface) and wr2 (the radius of the lower base surface), and is given by the following equation: C f =C f (r,wh,wr1,wr2,...)...(Equation 4)

[0066] Also, as shown in Figure 5, when air blasting a part with a wall on one side, the correction function C f is a function of at least the r coordinate, the θ coordinate, the height wh of the wall, and the distance wd to the wall, and is given by the following equation: C f =C f (r,θ,wh,wd...)...(Equation 5)

[0067] [Numerical simulator for air blast processing I] Numerical simulator I of the present invention is a numerical simulator that uses data on the cutting speed distribution of a jet, which is the distribution of the speed at which the workpiece surface is cut by the jet, in air blast processing, in which a jet containing compressed air and abrasive grains is sprayed vertically downward from a nozzle onto a workpiece surface perpendicular to the central axis of the nozzle.

[0068] The numerical simulator I of the present invention fits the cutting speed distribution of the jet containing compressed air and abrasive grains ejected from the nozzle to an equation using a Gaussian distribution, such as equation 1 above, which can be converted into data using two coefficients A and σ, and uses this equation to calculate and output (simulate) the shape of the cutting surface formed when the workpiece surface is cut when the nozzle is moved under specified movement conditions (e.g., movement path, movement speed, overlapping of movement paths, etc.).

[0069] The shape of the cut surface formed on the workpiece surface by air blasting is determined by the jet, which has a specific jet cutting speed distribution, and the movement conditions of the nozzle that sprays the jet (for example, the movement path, movement speed, overlapping of the movement path, etc.). Therefore, it is extremely difficult to accurately predict this without the aid of a computer.

[0070] As described above, numerical simulator I can calculate and output the shape of the cutting surface formed on the workpiece surface by air blasting by specifying a specific jet cutting speed distribution and specific movement conditions.

[0071] If the desired cutting surface does not have a very complex shape, the combination of the jet cutting speed distribution data and the movement conditions (machining process I) can be investigated by using Numerical Simulator I to change the jet cutting speed distribution data and the movement conditions in various ways, and observing the changes in the output surface shape through trial and error.

[0072] Furthermore, Numerical Simulator I is capable of setting the work surface before machining to any shape, and for example, it is possible to calculate the change in the unevenness of the work surface when machining an uneven work surface by moving the nozzle under the specified jet cutting speed distribution data and the specified movement conditions.

[0073] [Numerical simulator for air blast processing II] Furthermore, the above-mentioned numerical simulator I may be equipped with the function of fitting the jet cutting speed distribution to Equation 1 and archiving the relationship between the air blast processing conditions previously investigated through experiments and the digitized jet cutting speed distribution (A, σ) (numerical simulator II).

[0074] Here, the processing conditions for the air blasting are, as described above, for example, the workpiece material, nozzle, abrasive (type and size), spray amount, spray pressure, and the distance between the nozzle tip and the workpiece surface.

[0075] Numerical Simulator II can extract data on the corresponding jet cutting speed distribution by selecting the air blast processing conditions from the archive, and by specifying the above-mentioned movement conditions, it can calculate the surface shape of the workpiece surface that will be formed when processing is performed under the specified air blast processing conditions and the specified movement conditions.

[0076] In addition, Numerical Simulator II can set the work surface before processing to any shape, and can also calculate the change in the unevenness of the work surface when an uneven work surface is processed under the specified air blast processing conditions and specified movement conditions.

[0077] As described above, the numerical simulator II can calculate and output the shape of the cutting surface formed by the air blast by specifying certain processing conditions for the air blast and certain movement conditions.

[0078] If the desired cutting surface does not have a very complex shape, this numerical simulator II can be used to examine the combination of the air blast processing conditions and the nozzle movement conditions (processing process II) by observing the changes in the output surface shape (shape of the cutting surface) while changing the air blast processing conditions and the nozzle movement conditions in various ways, and by trial and error.

[0079] [Numerical simulator equipped with AI] The above-mentioned numerical simulator I or numerical simulator II may be equipped with AI, and the AI ​​may enable numerical simulator I to derive data on the cutting speed distribution of the jet and the movement conditions of the nozzle for machining a work surface of any shape into a desired shape, and also enable numerical simulator II to derive the machining conditions of the air blast and the movement conditions of the nozzle for machining a work surface of any shape into a desired shape.

[0080] If the desired cutting surface has a complex shape, it is extremely difficult and takes a huge amount of time and effort for an operator (person) to use trial and error with Numerical Simulator I or Numerical Simulator II to investigate the combination of the jet cutting speed distribution data that forms this and the movement conditions (machining process I) or the combination of the air blast machining conditions and the nozzle movement conditions (machining process II).However, a numerical simulator equipped with AI can reduce the enormous amount of time and effort required.

[0081] [NC air blast device] The above-mentioned Numerical Simulator I or Numerical Simulator II may be mounted on an air blast numerically controlled processing device, and the air blast numerically controlled processing device of the present invention is equipped with at least a nozzle that injects abrasive grains together with compressed air and a moving mechanism that moves the nozzle, as well as one or more of the above-mentioned Numerical Simulator I or Numerical Simulator II, or Numerical Simulator I equipped with AI or Numerical Simulator II equipped with AI. [Example]

[0082] [Measuring and digitizing cutting speed distribution] The cutting velocity distribution of the jet is approximated to a Gaussian distribution and formulated as in Equation 1, and an example is shown in which the coefficients A and σ in the equation are calculated.

[0083] According to the measurement method shown in Figure 3 above, under the air blast processing conditions in Table 1 below, the center of the nozzle is (0, μ, 0) (μ = 12.8), and the nozzle feed speed (v f The cutting groove was formed on the surface of the workpiece by moving the tool at 20 mm / s.

[0084] [Table 1]

[0085] As shown in Figure 6, the cross section of the cutting groove (i.e., the yz plane perpendicular to the x direction) was measured using a stylus roughness system, and the results are shown in Figure 7. In Figure 7, a Gaussian curve (hereinafter referred to as the approximation curve) that best matches the measurement results is plotted using the least squares method. As can be seen in Figure 7, the actual measurement data and the approximation curve are in good agreement.

[0086] The vertical axis of the cross-sectional curve in FIG. 7 indicates the cutting depth (μm) of the groove.

[0087] If the vertical axis of Figure 7 is Z and the horizontal axis is y, the equation for the approximate curve can be calculated as follows:

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[0088] When Equation 7 is compared with Equation 2, the coefficient A is A / v f = 69.7, so the coefficient A = 69.7 × 20 = 1394. The coefficient σ is σ = 2.76.

[0089] Then, the values ​​of the coefficients A and σ in equation 7 (actual measured values ​​of equation 2) obtained by the measurements described above can be converted into data as the values ​​of the coefficients A and σ in equation 1.

[0090] [Simulation example 1] A numerical simulator was used to simulate the following case: the nozzle sprays a jet of cutting speed distribution digitized in the above-mentioned example (A=1394, σ=2.76), and as shown in Figure 8, the nozzle is first positioned at a position where the jet does not hit the workpiece, spraying begins from there, the workpiece (length 200 mm) is fed at a feed rate according to the diagram shown in Figure 9 so as to pass along the x-axis (y=0) so as to cut longitudinally, and the nozzle is moved to a position where the jet does not hit the workpiece, completing the process.

[0091] The numerical simulator may be either Numerical Simulator I or Numerical Simulator II described above. For example, Numerical Simulator I can perform a simulation by inputting the values ​​of coefficient A and σ obtained from Equation 7 (data on the cutting speed distribution of the jet) and the above-mentioned nozzle movement conditions, while Numerical Simulator II can input the air blast processing conditions in Table 1, extract the corresponding values ​​of coefficient A and σ obtained from Equation 7 (data on the cutting speed distribution of the jet), and further input the above-mentioned nozzle movement conditions to perform a simulation.

[0092] The results of the simulation are shown in Figures 10 and 11.

[0093] FIG. 10 shows the cutting depth of the cutting surface formed by the above-mentioned feed machining at y=0 (on the x-axis), that is, the results (profile) of simulating the shape of the processed surface in the xz cross section.

[0094] FIG. 11 shows the results (profile) of simulating the shape of the work surface in the yz cross section passing through points A, B, and C shown in FIG.

[0095] As described above, the numerical simulator of the present invention can simulate the shape of the cutting surface formed on the workpiece surface in response to changes in the nozzle movement speed (feed rate) when the cutting speed distribution is constant due to a jet flow.

[0096] [Simulation example 2] For a nozzle that sprays a jet of cutting speed distribution digitized in the above example, when feed processing (cutting processing) is performed by moving it at a constant feed rate of 10 mm / s parallel to the x-axis direction as shown in Figure 12, the profile of the amount of cutting in the yz cross section can be expressed by the following equation at a point sufficiently far from the starting point of processing.

number

[0097] Equation 8 is expressed as Equation 2 with coefficients A = 1394, σ = 2.76, and v f = 10. Specifically, the value "139" in Equation 8 is A / v f = 1394 / 10 ≒ 139, and the value "2.76" in the formula was obtained when σ = 2.76.

[0098] Then, as shown in Figure 12, a numerical simulator was used to simulate the shape of the cutting surface (machined surface profile) that can be formed on the workpiece surface in the yz cross section at a location sufficiently far from the starting point of machining (x = 0) when the above-mentioned feed machining is overlapped with a spacing s in the y-axis direction, by changing the conditions of the spacing s.

[0099] First, we simulated the case where feed machining was repeated at intervals of s = 2·σ = 2 × 2.76 = 5.52 (Simulation 1), and the machined surface profile in the yz cross section was uneven and wavy, as shown in Figure 13.

[0100] Next, we simulated the case where feed machining was repeated at intervals of s = σ = 2.76 (Simulation 2), and found that the machined surface profile in the yz cross section could be machined into a smooth, flat surface, as shown in Figure 14.

[0101] Furthermore, when a simulation was performed (Simulation 3) in which feed machining was repeated at intervals of s = 1 / 2 · σ = 0.5 × 2.76 = 1.38 (half the interval of Simulation 2), the machined surface profile in the yz cross section was able to be machined flat with a cutting depth twice that of Simulation 2, as shown in Figure 15.

[0102] As described above, the numerical simulator can simulate the shape of the cutting surface formed on the workpiece surface according to the change in the overlap of the nozzle movement path under a constant cutting speed distribution by the jet flow. [Explanation of symbols]

[0103] 90 Processing equipment 91 wafers 93 Processing Tools 93a Nozzle 94 Moving mechanism 95 Control Unit

Claims

1. In air blasting, in which a jet containing compressed air and abrasive grains is sprayed vertically downward from a nozzle onto a workpiece surface perpendicular to the central axis of the nozzle, a cutting speed distribution of the jet, which is a distribution of the speed at which the workpiece surface is cut by the jet, is formulated using a Gaussian distribution equation as shown in Equation 1 below, and the cutting speed distribution of the jet is converted into data using the coefficients A and σ in Equation 1. [Equation 1] In Equation 1, dZ / dt is the height in the cylindrical axial direction in a cylindrical coordinate system (r, θ, dZ / dt) in which the central axis of the nozzle is the cylindrical axis. r in Equation 1 is the radius in the cylindrical coordinate system (r, θ, dZ / dt). t in Equation 1 is time.

2. A method for measuring the coefficients A and σ in formula 1 according to claim 1, The feed direction of the nozzle that sprays a jet containing compressed air and abrasive grains in a vertically downward direction is defined as the x direction, and the vertically downward direction is defined as the z direction. An orthogonal coordinate system (x, y, z) is set so that the xy plane of the origin overlaps with the surface to be machined that is perpendicular to the central axis of the nozzle. The nozzle is moved from an initial position where the jet jet from the nozzle does not hit the work surface, while keeping the distance between the work surface and the nozzle constant, and the jet jet is sprayed on the work surface at a feed speed v of the nozzle. f A cutting groove is formed on the workpiece surface by a feed process in which the nozzle is moved to a position where the center of the nozzle passes on a straight line (0, μ, 0) and the jet does not hit the workpiece surface, and the outline of a cross section of the cutting groove perpendicular to the feed direction of the nozzle is measured; A method for measuring the coefficients A and σ in formula 1, characterized in that the measurement result of the contour is approximated to the following formula 2, and the coefficients A and σ are obtained from formula 2. [Equation 2]

3. 2. The method for correcting the cutting velocity distribution of a jet according to claim 1, wherein Equation 1 is corrected by a correction function C f A method for correcting the cutting velocity distribution of a jet, characterized by correcting it as shown in Equation 3 by: [Equation 3]

4. When the center of the truncated cone is air blasted, the correction function C in Equation 3 f is axially symmetric and has at least the r coordinate, the height wh of the wall that obstructs the air flow, and the distance wr to the wall 1 , wr 2 4. The method for correcting the cutting velocity distribution of a jet according to claim 3, wherein the cutting velocity distribution is a function of . . . and is expressed by the following equation 4. C f = C f (r, wh, wr 1 , wr 2 , ···) ··· (Equation 4)

5. When air blasting a part with a wall on one side, the correction function C in Equation 3 f is a function of at least the r coordinate, the θ coordinate, the height wh of the wall obstructing the air flow, and the distance wd to the wall, and is expressed by the following equation 5. C f = C f (r, θ, wh, wd ···) ··· (Equation 5)

6. In air blasting, a jet containing compressed air and abrasive grains is sprayed vertically downward from a nozzle onto a workpiece surface perpendicular to the central axis of the nozzle. This numerical simulator utilizes data on the cutting speed distribution of the jet, which is the distribution of the speed at which the workpiece surface is cut by the jet, and applies the cutting speed distribution of the jet, which is the distribution of the speed at which the workpiece surface is cut by the jet, to an equation that uses a Gaussian distribution and can be converted into data using two coefficients in the equation.The simulator uses this equation to calculate and output the shape of the cutting surface formed on the workpiece surface when the nozzle is moved under specified movement conditions.

7. A numerical simulator that utilizes data on the cutting speed distribution of a jet according to claim 6, characterized in that it has a function of applying the cutting speed distribution of the jet to formula 1 of claim 1, and archiving the relationship between the air blast processing conditions that have been investigated in advance by experiments and the cutting speed distribution that is converted into data using the two coefficients A and σ in formula 1.

8. A numerical simulator utilizing data on the cutting speed distribution of a jet according to claim 6, characterized in that it is equipped with AI, and the AI ​​derives data on the cutting speed distribution of the jet and the movement conditions for machining the work surface into a desired shape.

9. A numerical simulator that utilizes data on the cutting speed distribution of a jet as described in claim 7, characterized in that it is equipped with AI and uses the AI ​​to derive the processing conditions and movement conditions of the air blast for processing the work surface into a desired shape.

10. 10. A numerically controlled air blast machining device comprising a nozzle for injecting abrasive grains and a movement mechanism for moving the nozzle, and comprising at least one numerical simulator according to any one of claims 6 to 9.

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