Numerical control device and machine tool

Abstract

A numerical control device according to one embodiment of the present disclosure is for controlling a machining mechanism having a plurality of feed shafts for relatively moving a workpiece and a tool and a tool shaft for determining the direction of the tool according to a machining program including one or more command sentences that include a function word specifying the type of the unit function and may include a setting word for specifying the details of the unit function. The numerical control device has a hale machining calculation unit for calculating the position of the plurality of feed shafts and the phase of the tool shaft for each control period on the basis of a hale machining command sentence that includes a prescribed hale machining word for specifying a hale machining as the function word and one or more character strings for specifying machining conditions including the contour shape of a portion for performing the hale machining of the workpiece as the setting word.

Description

Numerical control devices and machine tools

[0001] The present invention relates to a numerical control device and a machine tool.

[0002] For example, in order to finish the surface of a workpiece smoothly, a non-rotating tool is moved along the surface of the workpiece to scrape off the surface of the workpiece, known as hail machining (also called planer machining or slicing). In hail machining, the orientation of the tool needs to be maintained in a predetermined direction relative to the direction of movement relative to the workpiece. To perform such hail machining, there is also known a machine tool configured to maintain the rotational position of a spindle that normally rotates to rotate a rotary tool at a rotational position specified by a machining program or the like (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2018-134711

[0004] To perform helix machining using a machine tool, it is necessary to create a machining program that moves the tool relative to the workpiece and simultaneously changes the tool orientation according to the tool movement direction. However, it is not easy to grasp the tool movement direction and create a machining program that adjusts the tool orientation.

[0005] A numerical control device according to one aspect of the present disclosure is a numerical control device that controls a machining mechanism having a plurality of feed axes that move a workpiece and a tool relatively and a tool axis that determines the orientation of the tool, in accordance with a machining program that includes one or more command statements that include a function word that specifies the type of unit function and that may include a setting word that specifies details of the unit function, and has a hail machining calculation unit that calculates the positions of the plurality of feed axes and the phase of the tool axis for each control cycle based on a hail machining command statement that includes a predetermined hail machining word that specifies hail machining as the function word and one or more character strings that specify machining conditions including the contour shape of the portion of the workpiece that will be hail machined as the setting word.

[0006] While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments and is not to be limited to the disclosed exemplary embodiments.

[0007] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram illustrating a configuration of a machine tool 1 according to a first embodiment of the present disclosure. Fig. 2 is a schematic diagram illustrating hale machining.

[0008] The machine tool 1 moves the workpiece W and the tool T relative to one another, and machines the workpiece W with the tool T. The machine tool 1 does not rotate the tool T, but keeps the orientation of the tool constant with respect to the direction of movement relative to the workpiece W, and performs hailing, which involves scooping (cutting away) the surface layer of the workpiece W. The machine tool 1 includes a machining mechanism 10 and a numerical control device 20 that controls the machining mechanism 10. The numerical control device 20 itself is an embodiment of the numerical control device according to the present disclosure.

[0009] The machining mechanism 10 has a plurality of feed axes Ax, Ay, Az that move the workpiece W and the tool T relative to each other, and a tool axis Ac that determines the orientation of the tool T (angular position around the central axis of the tool T). If the machining mechanism 10 is a general-purpose device that can also perform machining using a rotary tool such as an end mill, the tool axis Ac can be used as a main axis that rotates the rotary tool.

[0010] The numerical control device 20 controls the operation of the feed axes Ax, Ay, and Az and the tool axis Ac of the machining mechanism 10 in accordance with a machining program. The numerical control device 20 may be realized by one or more computers equipped with a processor, memory, input / output interface, etc., and executing appropriate control programs. The numerical control device 20 includes a program memory unit 21 that stores the machining program, a hail machining calculation unit 22 that calculates the positions of the feed axes Ax, Ay, and Az and the phase of the tool axis Ac required for each control cycle to perform hail machining described in the machining program, and an operation control unit 23 that controls the operation of the feed axes Ax, Ay, and Az and the tool axis Ac to achieve the positions and phases calculated by the hail machining calculation unit 22. While the hail machining calculation unit 22 is a characteristic component of the present disclosure, the program memory unit 21 and the operation control unit 23 may be configured similarly to those in known numerical control devices. Note that these components merely categorize the functions of the numerical control device 20 and do not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0011] The machining program may be written in a language conforming to the well-known G-code, for example. The machining program includes one or more command statements that specify unit functions, such as operations that the numerical control device 20 should cause the machining mechanism 10 to perform and internal processing that the numerical control device 20 should execute. The command statements may include function words, which are character strings (including one character) that specify the type of unit function, and setting words, which are character strings that specify the details of the unit function. The setting words may be composed of a symbol (typically an alphabetic character written at the beginning) that specifies the setting method or setting target, and a character string (typically a number written following the alphabetic character) that specifies the setting content. The character string that specifies the setting content may be a numerical value that directly indicates the setting content, or may be a file name, address, or the like that specifies an external file.

[0012] When the unit function according to the present disclosure is executed in the machine tool 1, the machining program includes a hail machining command statement that includes a predetermined hail machining word, which is a function word that specifies hail machining as a unit function, and one or more setting words that specify machining conditions including the contour shape of the portion of the workpiece W that is to be hail machined. The hail machining calculation unit 22 analyzes the hail machining command statement and calculates the positions of the feed axes Ax, Ay, Az and the phase of the tool axis Ac.

[0013] The hail processing command preferably includes, as setting words, a character string specifying the basic shape of the contour shape of the part to be processed, a character string specifying the size of the contour shape, and a character string specifying the position of the contour shape. The basic shape may be, for example, a square, circle, triangle, line, sine curve, parabola, etc., and the character string specifying the basic shape may be a number pre-assigned to each shape. The character string specifying the size of the contour shape may be a numerical value such as the representative length of the contour shape or a ratio to a reference dimension. Furthermore, the character string specifying the size of the contour shape may be multiple setting words, such as two numerical values ​​specifying the size in each of two orthogonal directions, or two numerical values ​​specifying the representative size and the ratio of the dimensions in the two directions. Identifying the contour shape using these three character strings allows for relatively easy identification of the contour shape.

[0014] The hail machining command may also include a character string as a setting word that specifies which side of the contour shape (inside or outside in the case of a closed shape) to machine. This makes it easy to specify the hail machining of the inner edge of the opening of the workpiece W.

[0015] Furthermore, a hail machining command may include a character string specifying the offset amount (the distance between the reference point and the tooth tip) of the reference point of the tool T set on the tool axis Ac from the contour shape of the part to be machined, and a character string specifying the offset direction. This allows machining conditions to be set for each machining. Note that the offset amount and offset direction may be specified by referring to the header information of the machining program, information associated with the tool, etc., rather than by using setting words.

[0016] The hail processing command may also include character strings as setting words to specify the start and end points of the processing. This allows easy specification of any part of a basic shape, for example, and allows for the relatively simple specification of processing of complex shapes by joining parts of multiple basic shapes.

[0017] Furthermore, the hale machining command may include two character strings that specify two of the cutting depth, the machining allowance, and the number of machining operations, thereby allowing for easy specification of step-by-step machining.

[0018] The hail processing calculation unit 22 can be configured to apply a preset default value to setting items that are not described in a setting word in the hail processing command. This makes it easier to create a processing program because setting words only need to be described in the hail processing command when special settings are required. For example, when processing the outside of a basic shape, setting words can be omitted, and when processing the inside of the basic shape, setting words indicating this can be described.

[0019] For ease of understanding, the following non-limiting example of a hail machining command written in G-code is shown: "G106T1.P1.G42D100.X0.0Y0.0H100.0V100.0R10.0U1.Q1.120K3.F5000." In this hail machining command, "G106" is a hail machining word (function word) that specifies hail machining. "T1." is a setting word that indicates the number of a separately stored basic shape. "P1." is a setting word that indicates the inside / outside of the basic shape. "G42" is a setting word that indicates the offset direction (right / left) relative to the traveling direction of tool T. "D100." is a setting word that indicates the address where the offset amount is stored. "X0.0" is a setting word that indicates the X coordinate value of the reference position of the basic shape. "Y0.0" is a setting word that indicates the Y coordinate value of the reference position of the basic shape. "H100.0" is a setting word that indicates the dimension of the basic shape in the X direction. "V100.0" is a setting word that indicates the dimension of the basic shape in the Y direction. "R10.0" is a setting word that indicates the chamfer diameter of the corner of the basic shape. "U1." is a setting word that indicates the number of the point that is pre-set in the basic shape as the starting point for machining. "Q1.120" is a setting word that indicates the amount of cutting per time. "K3." is a setting word that indicates the number of times machining is performed. "F5000" is a setting word that indicates the movement speed of tool T.

[0020] Additionally, a G-code hafting command may call a subprogram that describes a cutting path that connects the start and end points of the cutting along the contour. An example is "G106T99.P0100G42D100.X-70.0Y20.0F5000." P is a setting word that indicates the subprogram that describes the cutting path. For example, if the subprogram is in NC program format, beginning with "O" and a four-digit program number, it can be called by specifying the four-digit program number after P. In the above example, command P0100 calls subprogram O0100. Furthermore, for example, if the subprogram is in text file format and the file name is defined with an arbitrary character string at the beginning, it can be called by specifying the file name in a specified format after P. For example, specifying P<PROFILE.TXT> calls a text file named "PROFILE.TXT." The subprogram can be configured to sequentially describe the coordinates of multiple command points on the contour shape in accordance with well-known programming rules. Figure 3 shows an example of a cutting path described in the subprogram, with a solid line and a dashed line showing the relative position of the tool T with respect to the workpiece (the positions of the feed axes Ax, Ay, Az) calculated by the hail machining calculation unit 22 based on this cutting path. As described above, a single setting word can easily perform hail machining of any contour shape.

[0021] Furthermore, a hail machining command written in G-code may include a character string specifying the phase difference between the tool axis Ac and the tool T, i.e., the difference (offset amount) between the phase of the tool axis Ac and the phase of the tool T caused by an attachment error of the tool T relative to the tool axis Ac. An example is "G106 W0.124." W is a setting word indicating the phase offset amount of the tool T. In hail machining, the phase of the tool T relative to the direction of travel must generally be appropriately adjusted, but the phase is not necessarily appropriate when the tool T is attached to the tool axis Ac. Specifically, in a machine in which the tool T can be attached and detached from the tool axis Ac via a tool holder or the like, the phase of the tool T may vary within the allowable range of the attachment phase of the tool holder relative to the tool axis Ac. For this reason, a phase offset amount must be set before machining or when the tool T is attached to correct the attachment error of the tool T relative to the tool axis Ac so that the tool T can be correctly oriented by the tool axis Ac. In the above example, the command W0.124 specifies 0.124° as the offset amount of the phase of the tool T relative to the phase of the tool axis Ac.

[0022] As described above, the machine tool 1 equipped with the numerical control device 20 having the above configuration can perform appropriate hail machining without the user having to specify the orientation of the tool T, because the hail machining calculation unit 22 calculates the required positions of the feed axes Ax, Ay, Az and the phase of the tool axis Ac from a hail machining command statement that does not include a word specifying the phase of the tool axis Ac. In other words, by using the numerical control device 20, the user can easily create a machining program that enables appropriate hail machining without having to be aware of the orientation of the tool T.

[0023] The following supplementary notes are further disclosed regarding the above-described embodiments and modifications: (Supplementary Note 1) A numerical control device (20) controls a machining mechanism having a plurality of feed axes (Ax, Ay, Az) for relatively moving a workpiece (W) and a tool (T) and a tool axis (Ac) for determining the orientation of the tool (T) according to a machining program including one or more command statements that include a function word specifying the type of unit function and that may include a setting word specifying details of the unit function, and has a hail machining calculation unit (22) that calculates the positions of the plurality of feed axes and the phase of the tool axis (Ac) for each control cycle based on a hail machining command statement that includes a predetermined hail machining word specifying hail machining as the function word and one or more character strings specifying machining conditions including a contour shape of a portion of the workpiece to be hail machined as the setting word.

[0024] (Supplementary Note 2) In the numerical control device (20) of Supplementary Note 1, the hail processing command statement may include, as setting words, a character string specifying a basic shape of the contour shape, a character string specifying a size of the contour shape, and a character string specifying a position of the contour shape.

[0025] (Supplementary Note 3) In the numerical control device (20) of Supplementary Note 1 or 2, the hail processing command may include, as a setting word, a character string that specifies the start point and end point of processing.

[0026] (Supplementary Note 4) In the numerical control device (20) of any one of Supplementary Notes 1 to 3, the hail machining command statement may include, as a setting word, a character string that specifies which side of the contour shape is to be machined.

[0027] (Supplementary Note 5) In the numerical control device (20) of any one of Supplementary Notes 1 to 4, the hale machining command statement may include, as setting words, two character strings that specify two of the cutting depth, the machining allowance, and the number of machining operations.

[0028] (Supplementary Note 6) In the numerical control device (20) of any one of Supplementary Notes 1 to 5, the hail machining command statement may include, as a setting word, a character string that calls a cutting path that connects the start point and end point of machining along the contour shape.

[0029] (Supplementary Note 7) In the numerical control device (20) of any one of Supplementary Notes 1 to 6, the hale machining command statement may include, as a setting word, a character string that specifies a phase difference between the tool axis (Ac) and the tool (T).

[0030] (Appendix 8) A machine tool (1) according to the present disclosure includes a numerical control device (20) according to any one of Appendices 1 to 7, and a machining mechanism (10) having a plurality of feed axes (Ax, Ay, Az) and a tool axis (Ac) controlled by the numerical control device (20).

[0031] Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the present disclosure or the gist of the present disclosure derived from the content of the claims and their equivalents.

[0032] REFERENCE SIGNS LIST 1 machine tool 10 machining mechanism 20 numerical control device 21 program memory unit 22 heli machining calculation unit 23 motion control unit Ac tool axis Ax, Ay, Az feed axis T tool W workpiece

Claims

1. A numerical control device that controls a machining mechanism having a plurality of feed axes that move the workpiece and tool relative to one another and a tool axis that determines the orientation of the tool, in accordance with a machining program that includes one or more command statements that include a function word that specifies the type of unit function and that may include a setting word that specifies details of the unit function, and that has a hair machining calculation unit that calculates the positions of the plurality of feed axes and the phase of the tool axis for each control cycle based on a hair machining command statement that includes a predetermined hair machining word that specifies hair machining as the function word and one or more character strings that specify machining conditions including the contour shape of the part of the workpiece that will be subjected to hair machining as the setting word.

2. A numerical control device according to claim 1, wherein the hail processing command statement includes, as the setting words, a character string specifying the basic shape of the contour shape, a character string specifying the size of the contour shape, and a character string specifying the position of the contour shape.

3. A numerical control device according to claim 1 or 2, wherein the hail machining command statement includes, as the setting words, character strings specifying the start and end points of machining.

4. A numerical control device according to any one of claims 1 to 3, wherein the hail machining command statement includes, as the setting word, a character string specifying which side of the contour shape is to be machined.

5. A numerical control device according to any one of claims 1 to 4, wherein the hail machining command statement includes, as the setting words, two character strings specifying two of the cutting depth, machining allowance, and number of machining operations.

6. A numerical control device according to any one of claims 1 to 5, wherein the hail machining command statement includes, as the setting word, a character string that calls a cutting path that connects the start point to the end point of machining along the contour shape.

7. A numerical control device according to any one of claims 1 to 6, wherein the hale machining command statement includes, as the setting word, a character string that specifies a phase difference between the tool axis and the tool.

8. A machine tool comprising: a numerical control device according to any one of claims 1 to 7; and a machining mechanism having a plurality of feed axes and a tool axis controlled by said numerical control device.

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