Cutting force coefficient predicting device, cutting force coefficient predicting method, and cutting force coefficient predicting program

Abstract

To make it possible to easily and appropriately estimate a cutting force coefficient.SOLUTION: In a converting-purpose computing machine 10, a storage resource 14 stores a plurality of corresponding relationships between a plurality of types of parameter values for a tool related to a cutting process and a cutting force coefficient of the tool in a cutting process with the plurality of types of parameter values, and a CPU 11 is configured so that: a plurality of determination tree models that estimate the cutting force coefficient are formed based on the plurality of corresponding relationships; a use parameter that is a parameter to be used is determined from among multiple parameters based on an error between the cutting force coefficients estimated by multiple determination tree models and a cutting force coefficient that is a correct answer; a use determination tree model is formed based on the use parameters; a designated parameter value is accepted which is the value of multiple parameters related to a cutting process for which a cutting force coefficient is to be estimated; and the use determination tree model is used to estimate a cutting force coefficient at the designated parameter value.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a technique for estimating a cutting force coefficient of a tool used in a processing machine for performing cutting processing. [Background technology]

[0002] In recent years, workpieces (hereinafter sometimes referred to as "workpieces") are sometimes machined by inputting NC programs into NC cutting machines.

[0003] For example, in machining using a rotary tool, machining errors may occur due to bending of the rotary tool or the like, and a technique is known in which the movement path of the tool is corrected in an NC program so as to cancel out the machining errors in advance.

[0004] For example, Patent Document 1 discloses a technique for predicting a machining error of a workpiece caused by the action of a cutting force on a rotary tool. In Patent Document 1, the cutting force coefficient used for estimating the cutting force is input in advance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-218641 A Summary of the Invention [Problem to be solved by the invention]

[0006] For example, in the technology of Patent Document 1, it is necessary to know the cutting force coefficient in advance in order to estimate the cutting force. In order to know the cutting force coefficient, for example, it is necessary to actually perform cutting processing using a rotating tool, and measure and calculate various values.

[0007] In this way, in order to grasp the cutting force coefficient, it is necessary to actually perform cutting processing and measure various values, which requires a long time for measurement.In addition, since various values ​​need to be measured, there is a problem that a measuring device required for the measurement must be provided.

[0008] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a technique that can easily and appropriately estimate a cutting force coefficient. [Means for solving the problem]

[0009] A cutting force coefficient estimation device according to one aspect is a cutting force coefficient prediction device that includes a processor and a memory unit and estimates the cutting force coefficient of a tool used in a processing machine that performs a cutting process, wherein the memory unit stores a plurality of correspondence relationships between values ​​of a plurality of types of parameters for the tool involved in the cutting process and the cutting force coefficient of the tool in the cutting process at the values ​​of the plurality of types of parameters, and the processor creates a plurality of decision tree models that estimate the cutting force coefficient by changing a combination of some of the plurality of types of parameters based on the plurality of correspondence relationships, determines a usage parameter that is a parameter to be used from among the plurality of parameters based on an error between the cutting force coefficient estimated by the plurality of decision tree models and a cutting force coefficient that is a correct answer, creates a usage decision tree model that is a decision tree model used to estimate the cutting force coefficient based on the usage parameter, accepts designated parameter values ​​that are values ​​of a plurality of types of parameters related to the cutting process that is the target for estimating the cutting force coefficient, and estimates the cutting force coefficient at the designated parameter value using the usage decision tree model. Effect of the Invention

[0010] According to the present invention, the cutting force coefficient can be easily and appropriately estimated. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram for explaining side surface processing. [Diagram 2]FIG. 2 is a diagram for explaining the groove machining. [Diagram 3] FIG. 3 is a diagram for explaining the areas of the tool used in side machining and groove machining. [Figure 4] FIG. 4 is a diagram showing the overall configuration of a processing system according to an embodiment. [Diagram 5] FIG. 5 is a configuration diagram of a conversion computer according to an embodiment. [Figure 6] FIG. 6 is a configuration diagram of cutting force coefficient information according to an embodiment. [Figure 7] FIG. 7 is a diagram showing an example of a cutting processing input screen according to an embodiment. [Figure 8] FIG. 8 is a diagram illustrating axial cuts and radial cuts according to one embodiment. [Figure 9] FIG. 9 is a flowchart of a path correction process according to an embodiment. [Figure 10] FIG. 10 is a flowchart of a cutting force coefficient calculation process according to an embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of a decision tree model according to an embodiment. [Figure 12] FIG. 12 is a diagram illustrating selection of feature amounts according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The following embodiments will be described with reference to the drawings. Note that the following embodiments do not limit the scope of the invention, and not all of the elements and combinations thereof described in the embodiments are necessarily essential to the solution of the invention.

[0013] In explaining an outline of an embodiment, first, side surface machining using a tool TL will be explained.

[0014] 1 is a diagram for explaining side surface machining, in which the X-axis indicates the moving direction of a tool TL, the Z-axis indicates the direction of the rotation axis of the tool TL, and the Y-axis indicates the direction perpendicular to the X-axis on a plane perpendicular to the rotation axis.

[0015] Side machining is a process in which the side surface of a workpiece W is cut by a tool TL by rotating the tool TL and moving it in the X-axis direction, as shown in FIG.

[0016] The cutting force in side machining can be expressed as shown in the following equation (1).

[0017]

number

[0018] Here, as shown in FIG. 1, Ft is the cutting force in the tool tangential direction, Fr is the cutting force in the tool radial direction, and Fa is the cutting force in the tool axial direction. Ktc, Krc, and Kac are cutting force coefficients of cutting forces generated by shearing of the workpiece, where Ktc is the cutting force coefficient in the tool tangential direction, Krc is the cutting force coefficient in the tool radial direction, and Kac is the cutting force coefficient in the tool axial direction. fz is the feed amount per tooth (feed per tooth), φ is the tool rotation angle, and dz indicates the thickness of the microelement in the tool axial direction. Kte, Kre, and Kae are cutting force coefficients generated by friction between the tool and the workpiece, where Kte is the cutting force coefficient in the tool tangential direction, Kre is the cutting force coefficient in the tool radial direction, and Kae is the cutting force coefficient in the tool axial direction.

[0019] Next, groove machining using the tool TL will be described.

[0020] FIG. 2 is a diagram for explaining the groove machining.

[0021] Groove machining is a process in which a workpiece W is cut with a tool TL to form a groove by rotating the tool TL and moving it in the X-axis direction, as shown in FIG.

[0022] The cutting force in groove machining can also be expressed as shown in formula (1). When distinguishing between the cutting force coefficient for side machining and the cutting force coefficient for groove machining, the symbol for each cutting force coefficient (Kte, etc.) is followed by _S for side machining, for example, Kte_S, and by _G for groove machining, for example, Kte_G.

[0023] Here, the difference between side surface machining and groove machining will be described.

[0024] FIG. 3 is a diagram for explaining the areas of the tool used in side machining and groove machining.

[0025] As shown in Fig. 3, the area of ​​the tool TL that is often used for side machining is the area on the positive side of the Y axis of the tool TL, and the area that is often used for groove machining is the area on the negative side of the Z axis of the tool TL. As such, the areas that are often used for side machining and groove machining are different, so the cutting force coefficients for side machining and groove machining are different.

[0026] <System configuration> FIG. 4 is a diagram showing the overall configuration of a processing system according to an embodiment.

[0027] The processing system 1 includes a conversion calculator 10 as an example of a cutting force coefficient prediction device, a plurality of NC cutting machines 20 (an example of a processing machine), and a plurality of on-site computers 30. The conversion calculator 10, the plurality of NC cutting machines 20, and the plurality of on-site computers 30 are connected via a network 40. The network 40 may be a wired network or a wireless network. In this embodiment, the NC cutting machines 20 and the on-site computers 30 are disposed at each of the locations A and B, and the conversion calculator 10 is disposed at the location C. The conversion calculator 10 may be disposed at either the location A or the location B. The plurality of NC cutting machines 20 and the plurality of on-site computers 30 may be disposed at the same location.

[0028] The conversion computer 10 executes a process of converting an NC program (conversion source NC program: pre-correction NC program) for a certain NC cutting machine 20 into an NC program (conversion destination NC program: post-correction NC program) for another NC cutting machine 20. Details of the conversion computer 10 will be described later.

[0029] The site computer 30 is a computer operated by a worker on site, and is configured, for example, by a PC (Personal Computer) equipped with a processor, storage resources, etc. In addition, the site referred to here is typically a place where the NC cutting machine 20 is installed (for example, inside a factory, a building, a floor, etc.) in Fig. 4. However, the site computer 30 may be used in a place other than the place where the NC cutting machine 20 is installed, so long as it is used for displaying the screen of the conversion computer 10.

[0030] In the following description, the on-site computer 30 is responsible for downloading and displaying the converted NC program and displaying the conversion input screen, etc., and the actual conversion process is performed by the conversion computer 10. However, although it may reduce convenience to some extent, the roles (including some roles) of each computer can be exchanged or integrated with each other. The conversion computer 10 may be composed of multiple computers. Therefore, the term "conversion system" may be used in the following description. This system includes one or more computers (on-site computer 30 or conversion computer 10) and is a system that performs the processes performed by the conversion computer 10 and on-site computer 30 described below. Some of the processes realized by the on-site computer 30 may be omitted.

[0031] The NC cutting machine 20 is, for example, a machining center, and includes a main body 22 that performs processing (e.g., cutting processing), an NC controller 21 that controls the processing of the main body 22, and a tool magazine 25 as an example of a storage section capable of storing tools TL of one or more tool sets used in the main body 22.

[0032] The tool magazine 25 has a plurality of slots (SL: 25a, 25b, 25c) each capable of accommodating one tool TL.

[0033] The NC controller 21 controls the machining process of the main body 22 and the tool replacement process in accordance with an NC program stored inside.

[0034] The main body 22 includes a processing head 23, a stage 24, and a tool exchanger 26. The processing head 23 is equipped with a spindle to which a tool TL can be attached and which can rotate. The processing head 23 may be the spindle itself. The stage 24 is movable with a workpiece W to be processed placed thereon. The tool exchanger 26 removes the tool TL from the processing head 23 and stores it in an empty slot of the tool magazine 25. The tool exchanger 26 also removes the tool TL from the slot of the tool magazine 25 and attaches it to the processing head 23. An example of the tool exchanger 26 is a change arm (also called an ATC arm) of an automatic tool changer (ATC). The above-mentioned tool magazine 25 is also a component of the automatic tool changer. An NC program can describe a series of commands (called codes in the terminology of NC programs or words with parameters added to the codes) that mean tool change commands, and the tool change command includes a slot number indicating the position of a slot (the meaning of which will be described later) in the tool magazine 25. The tool exchange unit 26 takes out a tool TL from a slot specified by the slot number included in the parameters of the tool exchange command in response to an instruction from the NC controller 21 that has read the tool exchange command, and attaches the tool TL to the processing head unit 23 .

[0035] In the NC cutting machine 20, there is a limit to the number of tools TL that can be stored in the tool magazine 25. However, by preparing one or more tool sets 50 in advance and changing the tool sets stored in the tool magazine 25 depending on the machining process to be performed, it is possible to accommodate a variety of machining processes.

[0036] In this embodiment, the tool TL includes a blade portion TLa such as an end mill, drill, or bit for cutting the workpiece W, and a holder TLb for attaching the blade portion TLa to the processing head portion 23. However, for example, if the blade portion TLa can be attached directly to the processing head portion 23, it does not need to include the holder TLb, and it is sufficient if it includes at least the blade portion TLa.

[0037] In the following description, an entity including at least a processing machine that has been performing processing using the NC program to be converted (i.e., the NC program for conversion source) and a tool set corresponding to the processing machine may be referred to as a "source environment". Also, an entity including at least a processing machine that is scheduled to perform processing using the converted NC program (i.e., the NC program for conversion destination) and a tool set corresponding to the processing machine may be referred to as a "destination environment". The source environment and the destination environment may include physical or logical entities included in each location (for example, the temperature, temperature sensor, humidity, humidity sensor, or the floor on which the processing machine is installed at the location, or the building that constitutes the location). The "tool set corresponding to the processing machine" includes not only the tool set already stored in the tool magazine of the processing machine, but also a tool set that may be stored in the tool magazine and used in the future. Typically, the tool set corresponding to the processing machine is installed in the same location as the processing machine.

[0038] Next, the conversion calculator 10 will be described in detail.

[0039] FIG. 5 is a configuration diagram of a conversion computer according to an embodiment.

[0040] <<Hardware>> The conversion computer 10 is, for example, a personal computer or a general-purpose computer. The conversion computer 10 includes a CPU 11, a network interface 12 (abbreviated as Net I / F in the figure), a user interface 13 (User I / F in the figure), a storage resource 14 as an example of a storage unit, and an internal network that connects these components.

[0041] The CPU 11 is an example of a processor, and can execute a program stored in the storage resource 14. The processor may be a GPU (Graphics Processing Unit), or may be another semiconductor device that executes a predetermined process. The storage resource 14 stores the program to be executed by the CPU 11, various information used by this program, the NC program used by the NC cutting machine 20, and the like. The storage resource 14 may be, for example, a semiconductor memory, a flash memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like, and may be either a volatile type memory or a non-volatile type memory.

[0042] The network interface 12 is an interface for communicating with external devices (eg, the on-site computer 30, the NC controller 21 of the NC cutting machine 20, etc.) via a network 40.

[0043] The user interface 13 is, for example, a touch panel, a display, a keyboard, a mouse, etc., but may be other devices as long as they can receive operations from an operator (user) and display information. The user interface 13 may be composed of a plurality of these devices.

[0044] <<Data etc.>> The memory resource 14 stores a conversion program 141 as an example of a cutting force coefficient prediction program, a configuration information acquisition program 142, processing machine configuration information 143, tool set information 144, individual tool information 145, a source NC program 146, a destination NC program 147, conversion history information 148, and cutting force coefficient information 149. The memory resource 14 may store other information. Details of each data and program will be explained from the next paragraph. Each information, or some items of each information, may be omitted.

[0045] *Machine configuration information 143. The machine configuration information 143 is configured, for example, as a table that stores information on each NC cutting machine 20. The machine configuration information 143 includes the following information for each NC cutting machine 20. (a1) Identifier (machine ID) of the NC cutting machine 20. The identifier of the NC controller 21 or the network address of the NC controller 21 may be used as the machine ID. (a2) Model number of NC cutting machine 20. (a3) Location where the NC cutting machine 20 is installed. (a4) The usage history of the NC cutting machine 20, for example, the hours of use, etc. (a5) The temperature of a predetermined portion of the NC cutting machine 20. The predetermined portion may be the spindle or stage 24 of the NC cutting machine 20. (a6) Information regarding the rigidity of a predetermined portion of the NC cutting machine 20 (for example, Young's modulus, deflection amount, etc. of the portion). The predetermined portion may be the main shaft or stage 24 of the processing head unit 23 of the NC cutting machine 20. (a7) The shape of a predetermined portion of the NC cutting machine 20. The shape of the predetermined portion may be the length of the spindle of the NC cutting machine 20 or the length of the stage 24. (a8) The maximum number of tools that can be accommodated in the tool magazine 25, i.e., the number of slots. (a9) An offset value set according to aging and the installation environment. This offset value is used to finely correct the coordinates when the tool moves in the NC program, for example, to correct a situation where the stage has tilted slightly due to aging. (a10) Manufacturer, model number, etc. of the NC controller 21. The description format of the NC program of the NC controller 21 may differ slightly depending on the manufacturer and model number, and this information is used to determine such a situation. (a11) Play of components such as the spindle and stage, movement accuracy (for example, the amount of backlash of the stage), straightness, flatness, parallel movement, vibration amplitude and vibration frequency during operation of the device.

[0046] In this embodiment, the information (a1), (a2), (a4), (a5), (a8), (a9), and (a10) are obtained, for example, from the NC controller 21 of the NC cutting machine 20, while the information (a3), (a6), (a7), and (a11) are obtained from information input by an operator. Note that the method of obtaining information is not limited to this, and at least a part of the information (a1), (a2), (a4), (a5), (a8), (a9), and (a10) may be obtained from information input by an operator via the user interface 13, and the information (a3), (a6), (a7), and (a11) that can be obtained from the NC controller 21 may be obtained from the NC controller 21. Note that the information that is to be obtained from the NC controller 21 may also be obtained from an alternative device (for example, another computer or a sensor itself).

[0047] *Tool information (tool set information 144 and individual tool information 145) The tool set information 144 is information for managing a group (set) consisting of one or more tools TL. The tool set information 144 is a set of identification information (tool set ID) of the tool set and identifiers or model numbers of one or more tools TL constituting the set.

[0048] The individual tool information 145 is information about each tool. The individual tool information 145 includes the following information. (b1) Identifier of the tool TL (tool ID: for example, serial number, etc.). If an individual ID is assigned to the blade part TLa or the holder TLb, the identifier of the tool TL may be the value of that individual ID. If no individual ID is assigned, the CPU 11 executing the configuration information acquisition program 142 may automatically assign the individual ID. (b2) Model number of the tool TL (an example of tool identification information). For example, the model numbers of the blade part TLa and the holder TLb that constitute the tool TL. If the tool TL is composed of only the blade part TLa, only the model number of the blade part TLa may be used. If the blade part TLa is composed of multiple parts, the model numbers of all of them may be used, or some of them may be used. (b3) The material, shape, rigidity (Young's modulus, deflection, etc.), usage history, temperature, etc. of the tool TL (e.g., each of the blade part TLa and the holder TLb). Here, since the rigidity varies depending on the material and shape of the tool TL, this information is also information about rigidity. Unless otherwise specified, "shape" includes not only the three-dimensional shape and cross-sectional shape generally shown in drawings and CAD data, but also representative values ​​obtained from the shape, such as the length, the length by which the blade part TLa protrudes from the holder TLb (blade protrusion length), the thickness of the blade part TLa, and the straightness of the blade part TLa. (b4) Information on the placement position (slot) of the tool magazine 25 in which the tool is to be stored (position information, slot number). In this embodiment, the information (b1) to (b4) is obtained, for example, from information input by an operator via the user interface 13. However, information that can be obtained from the NC controller 21 may be obtained from the NC controller 21.

[0049] *The source NC program 146 is an NC program used for processing in the source NC cutting machine 20 (referred to as the source NC cutting machine 20). The source NC program 146 may be tuned to suit the characteristics, state, etc. of the source NC cutting machine 20 in order to maintain a predetermined precision in the processing accuracy of the target object obtained by the source NC cutting machine 20 through processing.

[0050] *The destination NC program 147 is an NC program obtained by converting the source NC program 146 so as to fit the destination NC cutting machine 20 (referred to as the destination NC cutting machine 20). If no conversion process has been performed on any of the source NC programs 146, the destination NC program 147 does not exist.

[0051] *The conversion history information 148 is information that manages the history of the conversion process when converting the source NC program 146 into the destination NC program 147. The conversion history information 148 is information that associates, for example, identification information for identifying the conversion process with various information (input information, etc.) used during the conversion process.

[0052] FIG. 6 is a configuration diagram of cutting force coefficient information according to an embodiment.

[0053] *The cutting force coefficient information 149 includes a plurality of entries indicating the correspondence between the values ​​of a plurality of types of parameters (feature quantities) involved in cutting (cutting processing) by a tool and the cutting force coefficient by the tool. The entries of the cutting force coefficient information 149 include a tool ID 149a, a tool type 149b, a tool diameter 149c, a number of teeth 149d, a helix angle 149e, a blade length 149f, a coating 149g, a neck length 149h, a shank diameter 149i, a cutting force coefficient for side machining 149j, and a cutting force coefficient for groove machining 149k.

[0054] The tool ID 149a stores an identifier (tool ID: for example, serial number, etc.) of the tool TL corresponding to the entry. The tool type 149b stores the type (tool type) of the tool TL corresponding to the entry. The tool type includes, for example, square, ball, radius, etc. The tool diameter 149c stores the diameter of the tool TL. The number of blades 149d stores the number of blades of the tool TL. The twist angle 149e stores the twist angle indicating the inclination of the peripheral blade when the axial direction of the tool TL corresponding to the entry is used as a reference. The blade length 149f stores the blade length of the tool TL corresponding to the entry. The coating 149g stores the presence or absence of coating for the tool TL corresponding to the entry. In this embodiment, if the tool TL is coated, "1" is stored, and if not coated, "0" is stored. The neck length 149h stores the neck length of the tool TL corresponding to the entry. The shank diameter 149i stores the shank diameter of the tool TL corresponding to the entry.

[0055] The cutting force coefficient for side machining 149j stores the cutting force coefficient for side machining of the tool corresponding to the entry (first cutting force coefficient). Here, the cutting force coefficients include six cutting force coefficients Ktc_S, Krc_S, Kac_S, Kte_S, Kre_S, and Kae_S corresponding to side machining. The cutting force coefficient for groove machining 149k stores the cutting force coefficient for groove machining of the tool corresponding to the entry (second cutting force coefficient). Here, the cutting force coefficients include six cutting force coefficients Ktc_G, Krc_G, Kac_G, Kte_G, Kre_G, and Kae_G corresponding to groove machining.

[0056] In addition, the following information may be stored in the storage resource 14: *Workpiece W information. This information includes, for example, the shape data of the workpiece W before machining, the material, rigidity, and the target machining shape data of the workpiece W. The target machining shape data is data that indicates the target shape when machining using an NC program. If the workpiece W can be machined into the target shape, this means that the error is zero. *Information on the pre-conversion environment or the post-conversion environment other than the processing machine configuration information 143, the tool set information 144, and the individual tool information 145. To clarify this information, it may be called "other pre-conversion environment information" or "other pre-conversion environment information."

[0057] <Programs that run on conversion calculators> <<Conversion program 141>> The conversion program 141 executes the following processes by being executed by the CPU 11. Here, the execution of the conversion program 141 by the CPU 11 constitutes a conversion unit. *When an instruction to start conversion is given via the conversion input screen, the conversion program 141 reflects various information input to the conversion input screen in the processing machine configuration information 143, the tool set information 144, and the individual tool information 145. The conversion program 141 also accepts parameter values ​​and conditions related to cutting processing via the cutting processing input screen 200 (see FIG. 7). The conversion program 141 also executes a conversion process to convert the conversion source NC program 146 to be converted into the conversion destination NC program 147 based on various information input to the conversion input screen and the cutting processing input screen 200 and the information on the conversion destination environment or the information on the conversion source environment included in the processing machine configuration information 143, the tool set information 144, and the individual tool information 145, and stores the obtained conversion destination NC program 147 in the storage resource 14.

[0058] In the conversion process for converting the source NC program 146 into the destination NC program 147, for example, the conversion program 141 changes or adds instructions to the source NC program 146 based on information regarding the stiffness of the destination NC cutting machine 20 or the stiffness of the tool TL of the tool set 50 used in the destination NC cutting machine 20, to generate the destination NC program 147. Note that the added or changed instructions may be tool diameter compensation, tool length compensation, tool wear compensation, feed rate, or cutting speed, thereby avoiding a significant change in the machining work, such as an increase in the number of times the tool TL is machined. However, an instruction that increases the number of times the workpiece W is machined (for example, an instruction equivalent to test cutting) may be added.

[0059] For example, in the conversion process for converting the source NC program 146 into the destination NC program 147, the conversion program 141 executes a cutting force coefficient calculation process (see FIG. 10) for estimating (calculating) the cutting force coefficient of the tool TL.

[0060] Furthermore, when at least a part of the description format for the NC program differs between the NC controller 21 of the source NC cutting machine 20 and the NC controller 21 of the destination NC cutting machine 20, the conversion program 141 converts the part of the description of the source NC program that has a different description format into the description format for the NC controller 21 of the destination NC cutting machine 20. This allows the NC controller 21 of the destination NC cutting machine 20 to perform machining without any problems.

[0061] *After the conversion process, the conversion program 141 displays a download confirmation screen to confirm the download, and if an instruction to download is given, it transmits the destination NC program 147 to the NC controller 21 of the destination NC cutting machine 20 or the on-site computer 30 at the location where the destination NC cutting machine 20 is located.

[0062] <<Configuration information acquisition program 142>> The configuration information acquisition program 142 is executed by the CPU 11 to execute the following processes. * The configuration information acquisition program 142 acquires various pieces of information related to the NC cutting machine 20 from the NC controller 21. The acquired information includes the above-mentioned pieces of information (a1), (a2), (a4), (a5), (a8), (a9), and (a10). *The configuration information acquisition program 142 displays a conversion input screen on the user interface 13, and acquires various pieces of information from the worker via the conversion input screen (information (a3), (a6), (a7), and (a11)) relating to the NC cutting machine 20 acquired from the worker, and information relating to the tool set 50 (information (b1) to (b4))). The configuration information acquisition program 142 displays a cutting work input screen 200 on the user interface 13 and acquires various pieces of information from the worker via the cutting work input screen 200 .

[0063] Fig. 7 is a diagram showing an example of a cutting processing input screen according to an embodiment Fig. 8 is a diagram for explaining an axial cut and a radial cut according to an embodiment.

[0064] The cutting processing input screen 200 includes a tool parameter input area 201 and a processing condition input area 202. The tool parameter input area 201 is an area that accepts input of multiple types of parameters (designated parameters) for cutting processing, for example, values ​​(designated parameter values) of parameters related to the tool shape, etc. The parameters for cutting processing are parameters managed in the cutting force coefficient information 149, and include, for example, the tool type, helix angle, tool diameter, presence or absence of coating, number of blades, work material, etc.

[0065] The machining condition input area 202 is an area for receiving input of machining conditions for the workpiece w in the cutting process. The machining conditions include the axial depth of cut and the radial depth of cut in the cutting process. As shown in Fig. 8, the axial depth of cut indicates the width in the axial direction (Z-axis direction) of the part of the workpiece w cut by the tool TL, and the radial depth of cut indicates the width in the radial direction (Y-axis direction) of the part of the workpiece w cut by the tool TL.

[0066] Next, the processing operation by the conversion computer 10 will be described.

[0067] (Process 1) The configuration information acquisition program 142 (more precisely, the CPU 11 executing the configuration information acquisition program 142) acquires various pieces of information (e.g., (a1), (a2), (a4), (a5), (a8), (a9), and (a10)) relating to each NC cutting machine 20 that can be acquired from the NC controller 21 of each NC cutting machine 20 connected via the network 40. Note that this process does not need to be performed each time process 2 and subsequent processes described below are performed.

[0068] (Process 2) Next, the configuration information acquisition program 142 displays a conversion input screen, and receives the following specifications via the conversion input screen. *Specify the source NC program 146 to be converted. *Specifying information (machine ID) for identifying the NC cutting machine 20 (source NC cutting machine) that processed the workpiece W using the source NC program 146. *Specifying information (tool set ID) for identifying the tool set used in the machining process by the source NC program 146. *Specifying information (machine ID) for identifying the NC cutting machine (destination NC cutting machine 20) that will perform the new cutting of the workpiece W using the destination NC program 147 obtained by converting the source NC program 146. *Specifying information (tool set ID) for identifying the tool set to be used in the destination NC cutting machine 20. In addition, the configuration information acquisition program 142 accepts input (direct input or selective input) of various information regarding the source NC cutting machine 20 and the destination NC cutting machine 20 ((a3), (a6), (a7), and (a11)), as well as information regarding the tool set 50 used in the source NC cutting machine 20 and the tool set 50 to be used in the destination NC cutting machine 20 (information (b1) to (b4)). In addition, the configuration information acquisition program 142 displays a cutting processing input screen 200 and accepts cutting processing parameters such as tool type, twist angle, tool diameter, presence or absence of coating, number of blades, workpiece material, etc., as well as axial cutting depth and radial cutting depth, via the cutting processing input screen 200.

[0069] (Process 3) Upon receiving an instruction to start conversion from a user, the configuration information acquisition program 142 transmits the instruction to start conversion to the conversion program 141. Here, the instruction to start conversion includes various information input (direct input or selective input) to the conversion input screen and various information input to the cutting processing input screen 200.

[0070] (Process 4) When the conversion program 141 receives a conversion start instruction, it reads the specified source NC program 146 (pre-correction NC program) and converts the source NC program 146 into a destination NC program 147 (corrected NC program) based on the information included in the conversion start instruction (at least information regarding the rigidity of the destination NC cutting machine 20 or the tool set used in the destination NC cutting machine 20), and stores the converted destination NC program 147 in the memory resource 14.

[0071] (Process 5) Next, the conversion program 141 displays a download confirmation screen. Note that, instead of automatically displaying the download confirmation screen after completion of process 4, the download confirmation screen may be displayed in response to an operation of the site computer 30 by the user of the site computer. After this, when a download instruction is received, the conversion program 141 transmits the destination NC program 147 to the NC controller 21 of the destination NC cutting machine 20 or the site computer 30 at the location of the destination NC cutting machine 20.

[0072] For example, in the case where the destination NC program 147 is transmitted to the NC controller 21, the NC controller 21 stores the received destination NC program 147 and can execute the destination NC program 147 in the subsequent machining process. On the other hand, in the case where the destination NC program 147 is transmitted to the site computer 30, the site computer 30 stores the destination NC program 147. Thereafter, the destination NC program 147 of the site computer 30 is stored in the NC controller 21 via the network 40 or a recording medium, etc., so that the NC controller 21 can execute the destination NC program 147.

[0073] <Example of conversion process using conversion program> Next, a specific example of the processing operation by the conversion computer 10 will be described.

[0074] 9 is a flowchart of a path correction process according to an embodiment. The path correction process is executed in the conversion process.

[0075] First, the conversion program 141 receives information on all blocks of the source NC program 146 to be processed, as well as the material shape and tool shape (S1). Here, a block refers to a description portion including a command (address) that can be instructed to the NC cutting machine 20 at one time in the processing executed by the source NC program 146. A block includes one or more commands (addresses) that can be instructed simultaneously. For example, an address may include a code indicating the type of command and a parameter related to the command content. If the source NC program 146 has a large capacity and it is not possible to call up all the blocks in the work area of ​​the memory, the block to be read may be switched according to the progress of the processing.

[0076] Next, the conversion program 141 performs the following processes (steps S2 to S5) on each of the blocks (referred to as target blocks) that are to be subjected to cutting processing on the workpiece W among the read blocks:

[0077] For the target block, the conversion program 141 performs a cutting force coefficient calculation process (see FIG. 10) for estimating a cutting force coefficient for the tool TL in the cutting process (S2).

[0078] Next, for the target block, the conversion program 141 calculates the cutting force applied to the tool TL in the cutting process by the target block (S3). Specifically, the conversion program 141 calculates the cutting force applied to the tool TL from the shape of the workpiece W, the tool shape, and the cutting force coefficient, based on the shape of the processing part, etc.

[0079] Next, the conversion program 141 determines a correction amount of the path for the tool TL based on the cutting force (S4). Here, the correction amount is, for example, the amount of deflection deformation occurring at the tip of the tool TL.

[0080] Next, the conversion program 141 updates each target block to a block that reflects the determined correction amount, and stores the converted NC program 147 including the updated blocks in the storage of the memory resource 14 (S5).

[0081] According to this path correction process, it is possible to create a destination NC program 147 in which the cutting process blocks have been corrected to an appropriate correction amount.

[0082] Next, the cutting force coefficient calculation process in step S2 will be described.

[0083] FIG. 10 is a flowchart of a cutting force coefficient calculation process according to an embodiment.

[0084] The conversion program 141 accesses and obtains the cutting force coefficient information 149 (S11).

[0085] Next, the conversion program 141 executes the processes of steps S12 to S17 for the six cutting force coefficients in side surface machining (Ktc_S, Krc_S, Kac_S, Kte_S, Kre_S, Kae_S) and the six cutting force coefficients in groove machining (Ktc_G, Krc_G, Kac_G, Kte_G, Kre_G, Kae_G). Here, the target cutting force coefficient is called the target cutting force coefficient.

[0086] In step S12, the conversion program 141 stores the number of parameters (feature amounts) (feature amount number) of the cutting force coefficient information 149 in the variable i_num, and sets the variable i to 0 (S12).

[0087] Next, the conversion program 141 creates a decision tree model for estimating a target cutting force coefficient by a combination of multiple feature quantities other than the feature quantity i (i-th feature quantity) based on the cutting force coefficient information. Note that the method for creating a decision tree model by multiple feature quantities can be realized by a known technique.

[0088] FIG. 11 is a diagram illustrating an example of a decision tree model according to an embodiment.

[0089] A decision tree model in which the target cutting force coefficient is KTC is, for example, as shown in Fig. 11. This decision tree model makes it possible to estimate KTC according to the values ​​of multiple feature quantities such as the tool diameter, helix angle, number of teeth, and the presence or absence of coating.

[0090] Returning to the explanation of Fig. 10, the conversion program 141 estimates a target cutting force coefficient for predetermined test data (a set of parameter values ​​having a cutting force coefficient that is the correct solution) using the created decision tree model, and calculates a value related to the error between the target cutting force coefficient estimated by the decision tree model for the feature i (when the feature i is excluded) and the cutting force coefficient that is the correct solution (for example, an average accuracy rate decrease rate indicating a decrease in the accuracy rate when estimation is made using the feature excluding the feature i). Here, the average accuracy rate decrease rate can be calculated by a known technique.

[0091] Next, the conversion program 141 judges whether i=i_num (S15). As a result, if i=i_num is not true (S15: No), this means that decision tree models have not been created for all combinations of multiple feature quantities excluding each of the feature quantities, so the conversion program 141 advances the process to step S13 and performs the same process.

[0092] On the other hand, when i=i_num (S15: Yes), it means that decision tree models for all combinations of multiple feature values ​​excluding each of the feature values ​​have been created, so the conversion program 141 determines feature values ​​(used feature values: used parameters) to be used to create the decision tree model to be used from all feature values ​​based on the average accuracy rate reduction rate for each feature value, and creates a decision tree model (used decision tree model) using the used feature values ​​of the cutting force coefficient information 149 (S17). Here, the used feature values ​​may be, for example, a predetermined number of feature values ​​with the highest average accuracy rate reduction rates among the multiple feature values, or all feature values ​​with the average accuracy rate reduction rate equal to or greater than a predetermined threshold value. This makes it possible to create a decision tree model with high prediction accuracy by removing feature values ​​that have no or little effect on the estimation of the cutting force coefficient.

[0093] Fig. 12 is a diagram illustrating selection of features according to an embodiment, in which the horizontal axis indicates the removed features, and the vertical axis indicates the corresponding average accuracy rate reduction rate.

[0094] The average accuracy rate decrease rate of feature amount i calculated in step S14 (average accuracy rate decrease rate when feature amount i is excluded) can be expressed, for example, as shown in Fig. 12. In this case, for example, the top feature amounts having the largest average accuracy rate decrease rates, for example, feature amount 0, feature amount 1, and feature amount 2 in the example of Fig. 12, may be determined as the feature amounts to be used.

[0095] Returning to the explanation of Figure 10, by performing the processing of steps S12 to S17 on each of the six cutting force coefficients in side machining and the six cutting force coefficients in groove machining, a decision tree model to be used for estimating each cutting force coefficient is created.

[0096] Next, the conversion program 141 estimates (calculates) six cutting force coefficients for side machining and six cutting force coefficients for groove machining using each decision tree model used based on the parameters input via the cutting machining input screen 200 (S18).

[0097] Next, the conversion program 141 calculates cutting force coefficients (Ktc_R, Krc_R, Kac_R, Kte_R, Kre_R, and Kae_R) corresponding to the target cutting process based on the input ratio of the radial cut-in and the axial cut-in (S19). Specifically, the cutting force coefficients (Ktc_R, Krc_R, Kac_R, Kte_R, Kre_R, and Kae_R) are calculated by the following formula (2).

[0098] Cutting force coefficient = (Cutting force coefficient for side machining) × (Axial depth of cut / (Axial depth of cut + Diameter depth of cut)) + (Cutting force coefficient for groove machining) x (radial depth of cut / (axial depth of cut + radial depth of cut)) (2)

[0099] For example, Ktc_R is as shown in the following equation (3). Ktc_R = Ktc_S × (shaft cut / (shaft cut + diameter cut)) + Ktc_G × (diameter cut / (shaft cut + diameter cut)) (3) In this way, the cutting force coefficient corresponding to the target cutting process is calculated from the cutting force coefficient for side machining and the cutting force coefficient for groove machining based on the ratio of radial cut to axial cut, so that the cutting force coefficient according to the target cutting process can be calculated with high accuracy.

[0100] <Actions and Effects> In this way, according to the cutting force coefficient calculation process, it is possible to create an appropriate decision tree model and estimate the cutting force coefficient based on the pre-stored cutting force coefficient information 149, without actually performing various measurements using the tool TL.

[0101] <Variations> The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention. The processes described below may be used in combination.

[0102] <<Other uses of on-site computers>> In the above embodiment, an example was described in which the conversion input screen, the download confirmation screen, and the cutting input screen are displayed on the user interface 13 of the conversion calculator 10 to accept input, but the present invention is not limited to this. The conversion input screen, the download confirmation screen, and the cutting input screen may be displayed on any of the site calculators 30 to accept input, for example, they may be displayed on the site calculator 30 at the location of the conversion destination NC cutting machine 20 to accept input. Also, a part of the conversion input screen may be displayed on the site calculator 30 at the location of the conversion source NC cutting machine 20 to accept input, and the remaining part of the conversion input screen may be displayed on the site calculator 30 at the location of the conversion destination NC cutting machine 20 to accept input.

[0103] <<<Others>>> In the above embodiment, a part or all of the processing performed by the CPU 11 may be performed by a hardware circuit. The program in the above embodiment may be installed from a program source. The program source may be a program distribution server or a non-volatile recording medium (e.g., a portable recording medium).

[0104] The source NC program may be an NC program immediately after it has been generated from the target shape data by the CAM program and before it is cut by the processing machine. In this case, the tool set may be input with the tool data when the NC program was generated by the CAM program. The amount of correction of the tool path may be determined based on the rigidity of the workpiece W and the amount of thermal expansion of the workpiece W during cutting (or, conversely, the amount of thermal contraction after cutting), in addition to the spindle rigidity or tool rigidity described above.

[0105] In the above embodiment, two types of cutting force coefficients, a cutting force coefficient for side machining and a cutting force coefficient for groove machining, are stored as the cutting force coefficients of the cutting force coefficient information, but only one of them may be stored. In this case, it is not necessary to accept the machining conditions from the operator, and the cutting force coefficient obtained from the created usage decision tree model can be used as it is as the cutting force coefficient for the target cutting process.

[0106] In the above embodiment, the calculated cutting force coefficient may be stored in a storage resource, or the calculated cutting force coefficient may be displayed.

[0107] In addition, the multiple parameters involved in the cutting process by the tool are not necessarily all of the multiple parameters included in the above-mentioned cutting force coefficient information 149. For example, at least some of the parameters may be included, or other parameters may be added.

[0108] In addition, in the above embodiment, the values ​​of multiple parameters included in the cutting force coefficient information 149 involved in the cutting process are accepted via the cutting processing input screen 200, but it is also possible to accept, for example, the values ​​of only the parameters used in the usage decision tree model.

[0109] In the above description, a machining center has been mainly used as an example of a processing machine, but other processing machines may be used as long as they are NC controllable.

[0110] In the above explanation, data transmission and reception between the on-site computer and the conversion computer has been partially omitted, but naturally, data transmission and reception is performed between the on-site computer and the conversion computer. For example, when the conversion program 141 is executed on the conversion computer and the on-site computer displays a user interface or displays or inputs information by the operation, a program that handles part of the processing that the configuration information acquisition program handles is executed on the on-site computer. Then, the program that handles that part transmits the input information to the conversion computer, or receives the display information transmitted from the conversion computer and displays the user interface. [Explanation of symbols]

[0111] 1 Processing system, 10 Conversion computer, 11 CPU, 12 Network interface, 13 User interface, 14 Memory resource, 20 NC cutting machine, 21 NC controller, 30 On-site computer, 50 Tool set, W Work, TL Tool

Claims

1. A cutting force coefficient prediction device including a processor and a storage unit, which estimates a cutting force coefficient of a tool used in a processing machine that performs cutting processing, The storage unit is storing a plurality of correspondence relationships between values ​​of a plurality of types of parameters for a tool involved in the cutting process and cutting force coefficients of the tool in the cutting process at the values ​​of the plurality of types of parameters; The processor, creating a plurality of decision tree models for estimating the cutting force coefficient by changing a combination of some of the plurality of types of parameters based on the plurality of correspondence relationships; determining a parameter to be used from among a plurality of parameters based on an error between the cutting force coefficients estimated by the plurality of decision tree models and a correct cutting force coefficient; creating a usage decision tree model, the usage decision tree model being used to estimate the cutting force coefficient based on the usage parameters; receiving designated parameter values, which are values ​​of multiple types of parameters related to a cutting process for which a cutting force coefficient is to be estimated; Using the decision tree model to estimate cutting force coefficients at the specified parameter values. Cutting force coefficient prediction device.

2. The storage unit is The cutting force coefficients include a first cutting force coefficient in side machining and a second cutting force coefficient in groove machining, The processor, creating a plurality of the decision tree models for each of the first cutting force coefficient and the second cutting force coefficient, determining the usage parameters for each of the first cutting force coefficient and the second cutting force coefficient, and creating the usage decision tree model; Estimating a cutting force coefficient in side machining and a cutting force coefficient in groove machining for the specified parameter values. The cutting force coefficient prediction device according to claim 1 .

3. The processor, receiving a radial depth of cut and an axial depth of cut in a cutting process for which a cutting force coefficient is to be estimated; A cutting force coefficient in the cutting process is estimated based on the estimated cutting force coefficient in the groove machining and the cutting force coefficient in the side machining and the ratio of the radial cut to the axial cut. The cutting force coefficient prediction device according to claim 2 .

4. The processor, The parameters to be used are determined from among the plurality of parameters based on a decrease rate of an average accuracy rate of a decision tree model not using each parameter. The cutting force coefficient prediction device according to claim 1 .

5. The processor, The multiple types of parameters for the tool involved in the cutting process include multiple parameters of the tool type, the tool diameter, the number of teeth of the tool, the helix angle of the tool, whether the tool is coated, and the material of the workpiece to be cut by the tool. The cutting force coefficient prediction device according to claim 1 .

6. The processor, An NC program for performing the cutting process is generated based on the estimated cutting force coefficient. The cutting force coefficient prediction device according to any one of claims 1 to 5.

7. A cutting force coefficient prediction method by a cutting force coefficient prediction device that estimates a cutting force coefficient of a tool used in a processing machine that performs cutting processing, comprising: The cutting force coefficient prediction device comprises: storing a plurality of correspondence relationships between values ​​of a plurality of types of parameters for a tool involved in the cutting process and cutting force coefficients of the tool in the cutting process at the values ​​of the plurality of types of parameters; creating a plurality of decision tree models for estimating the cutting force coefficient by changing a combination of some of the plurality of types of parameters based on the plurality of correspondence relationships; determining a parameter to be used from among a plurality of parameters based on an error between the cutting force coefficients estimated by the plurality of decision tree models and a correct cutting force coefficient; creating a usage decision tree model, the usage decision tree model being used to estimate the cutting force coefficient based on the usage parameters; receiving designated parameter values, which are values ​​of multiple types of parameters related to a cutting process for which a cutting force coefficient is to be estimated; Using the decision tree model to estimate cutting force coefficients at the specified parameter values. Cutting force coefficient prediction method.

8. A cutting force coefficient prediction program executed by a computer to estimate a cutting force coefficient of a tool used in a processing machine performing a cutting process, The computer creating a plurality of decision tree models for estimating the cutting force coefficient by changing a combination of some of the plurality of types of parameters based on a plurality of correspondence relationships between values ​​of a plurality of types of parameters for a tool involved in the cutting process and a cutting force coefficient of the tool in the cutting process at the values ​​of the plurality of types of parameters; determining a parameter to be used from among a plurality of parameters based on an error between the cutting force coefficient estimated by the plurality of decision tree models and a correct cutting force coefficient; creating a usage decision tree model, the usage decision tree model being used to estimate the cutting force coefficient based on the usage parameters; accepting designated parameter values, the designated parameter values ​​being values ​​of a plurality of types of parameters related to a cutting process for which a cutting force coefficient is to be estimated; Using the decision tree model to estimate cutting force coefficients at the specified parameter values. Cutting force coefficient prediction program.

Images