JP4234542B2 - Machining program creation device - Google Patents

Description

  The present invention relates to a machining program creation device that automatically creates a machining program for an NC machine tool.

  In recent years, some NC machine tools are equipped with a machining program creation device that automatically creates a machining program for machining a workpiece. As a typical machining program creation device, for example, an NC device display 2. Description of the Related Art An interactive machining program creation device that automatically creates a machining program if data is input in a form that answers questions or input requests that are sequentially displayed on the screen is widely known.

  For example, when performing pocket machining on a workpiece, a rotary cutting tool is first used by performing helical cutting in the axial direction (the depth direction of the pocket) using a tool such as an end mill in an area where pocket machining is to be performed. After forming a circular recess including a machining start point (hereinafter simply referred to as “machining start point”) of the cutting process in the radial direction, the machining start point in the circular recess is used as a starting point so as to follow the pocket shape. However, when the machining program for pocket machining is automatically created by the interactive machining program creation device, the machining start point is automatically set at the center of the pocket shape. At the same time, the helical center, which is the turning center of the tool in helical cutting, is automatically set at this machining start point.

  Therefore, in the pocket machining machining program automatically created by the conventional interactive machining program creation device, as shown in FIGS. 6 and 7, first, the tool is set at the machining start point A set at the center of the pocket shape PS. After T is positioned, as shown by a one-dot chain line in the figure, a helical cutting operation start point (hereinafter referred to as a helical descent start point) shifted from the machining start point A by the helical radius r input by the operator. The tool T is moved to B, and the helical cutting operation is started from the helical descent start point B. When the helical cutting operation is completed, the tool returns again to the machining start point A set at the center of the pocket shape PS, and the radial direction of the tool T extends from the machining start point A along the pocket shape PS. The cutting process is started. In the tool path shown in FIG. 7, the movement operation of the tool T without cutting is indicated by a dotted line, the helical cutting operation by the tool T is indicated by a solid line, and the cutting operation in the radial direction of the tool T is indicated by a one-dot chain line. ing.

JP 2000-305615A

  However, in the pocket machining machining program automatically created by the conventional interactive machining program creation apparatus, as described above, when the helical cutting operation is performed, the tool T is once positioned at the machining start point A and then the helical machining operation is performed. When moving from the helical cutting operation to the cutting operation in the radial direction of the tool T, the movement starts from the helical descent start point B to the machining start point A. There is a problem that the machining time of the workpiece W becomes longer by the time required for the movement of the tool, and the pocket machining of the workpiece W cannot be performed efficiently in a short time.

  Therefore, it is conceivable to reduce useless movement of the tool T by positioning the tool T directly at the helical descent start point B that is offset from the center of the pocket shape, rather than positioning the tool T at the machining start point A. In general machining programs for pocket machining, as described above, since the positioning is always performed at the center of the pocket shape, there is a machining program for positioning the tool T at a point other than the center of the pocket shape. Once created, the operator is expected to have a suspicion that the machining start point is incorrect when the machining program is first run on a trial basis. There is a problem that it is necessary to perform confirmation work.

  Accordingly, an object of the present invention is to provide a machining program creation device capable of creating a machining program that can efficiently perform pocket machining of a workpiece in a short time and that does not require the operator to perform a work of confirming the machining start point. Is to provide.

To solve the above problems, the invention according to claim 1 is a machining program creating device for automatically creating NC machine tool machining program, by performing a helical cutting in the axial direction of the end mill, said mill When creating a machining program for pocket machining that performs machining in the radial direction of the end mill from the machining start point in the circular recess after forming a circular recess including the machining start point of the cutting in the radial direction The present invention provides a machining program creation device characterized in that a helical descent start point, which is a starting point of a helical cutting operation, is set as a machining start point of cutting in the radial direction of the end mill .

  According to a second aspect of the present invention, in the machining program creation device according to the first aspect of the present invention, when the helical cutting is performed according to the input helical radius, it is determined whether or not overcutting occurs. If too much occurs, a notification that the input helical radius is not appropriate is made.

  The invention according to claim 3 determines whether or not excessive cutting occurs when the machining program creation device of the invention according to claim 1 or 2 performs helical cutting according to the input helical radius. When excessive cutting occurs, the input incorrect helical radius is automatically corrected to an appropriate helical radius that does not cause excessive cutting.

As described above, in the machining program creation device according to the first aspect of the present invention, since the helical descent start point of the end mill is set as the machining start point, the pocket machining created by the conventional machining program creation device. Unlike the machining program, it is not necessary to move the end mill between the machining start point and the helical descent start point, and after positioning to the machining start point, helical cutting can be started immediately and helical cutting can be started. When the machining is completed, cutting in the radial direction of the end mill can be started immediately. Therefore, the workpiece machining time is shortened, and the workpiece pocket machining can be efficiently performed in a short time.

In addition, in the machining program created by this machining program creation device, as with the pocket machining machining program created by the conventional machining program creation device, when the workpiece pocket machining is started, the end mill is usually the pocket machine. Positioned at the machining start point set at the center of the shape, the operator will not have the suspicion that the machining start point is wrong when the machining program is first run on a trial basis. There is no need to confirm the processing start point.

  However, when pocket machining is performed according to the machining program created by the machining program creation device, the circular recess to be helically cut performs pocket machining according to the pocket machining machining program created by the conventional machining program creation device. As in the case, it is not formed at the center of the processed shape, but is formed in a state shifted to one side, so that the frequency of excessive cutting increases. Therefore, as in the machining program creation device of the invention according to claim 2, when the helical cutting is performed according to the input helical radius, it is determined whether or not overcutting occurs. If the user is informed that the input helical radius is not appropriate, the operator can recognize that appropriate machining cannot be performed with the input helical radius.

  In particular, as in the case of the machining program creation device of the invention according to claim 3, when performing helical cutting according to the input helical radius, it is determined whether or not overcutting occurs, and when overcutting occurs. If an incorrect helical radius that has been input is automatically corrected to an appropriate helical radius that does not cause over-cutting, an appropriate machining program can be created without requiring the operator to input a correction for the helical radius. be able to.

  Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a functional block diagram of an interactive machining program creation device 1 mounted on an NC machine tool. As shown in the figure, the interactive machining program creation device 1 is configured from a keyboard or the like for inputting various information such as workpiece shape data such as product shape and material shape and machining conditions such as helical radius in helical cutting. An input unit 11, a storage unit 12 including a RAM or the like in which workpiece shape data, machining conditions and selected tool information, a tool database and the like are stored, and a display including a CRT on which an interactive screen such as a data input screen is displayed When the helical cutting is performed according to the part 13, the tool selection part 14 that selects a tool to be used based on the shape data of the work, and the input helical radius, it is determined whether or not the work is excessively cut. Overcutting determination unit 15, program creation unit 16 that creates a tool path and converts it into a machining program, input unit 11, storage 12, a display unit 13, a tool selection unit 14, an overcutting determination unit 15, and a control unit 17 that comprehensively controls the program creation unit 16. The tool selection unit 14, overcutting determination unit 15, and program creation unit 16 and the control part 17 are comprised by CPU. The machining program created by the program creation unit 16 is transmitted to the NC device 2 via the interface 18 and stored in the storage unit of the NC device 2.

  A case where a machining program for performing pocket machining on a workpiece is created by the interactive machining program creation apparatus 1 configured as described above will be described below with reference to the flowchart shown in FIG.

  As shown in the figure, first, when an operator inputs workpiece shape data such as product shape or material shape, or part of machining conditions such as helical radius in helical cutting (step S1), the input workpiece shape data. And input data such as a helical radius are stored in the working area of the storage unit 12. Here, the tool selection unit 14 selects a rotary cutting tool such as an end mill as a pocket machining tool based on the workpiece shape data (step S2), and the tool information of the pocket machining tool is stored in the storage unit 12. And is stored in the working area of the storage unit 12. Subsequently, a machining condition is calculated from the input shape data and the extracted tool information (step S3), and the calculated machining condition is stored in the working area of the storage unit 12.

  When the workpiece shape data, the tool information of the pocket machining tool, and the machining conditions are determined in this manner, the overcutting determination unit 15 performs intersection calculation based on these information (step S4). At this time, as shown in FIG. 3, the machining start point A is set at the center of the pocket shape PS, and the helical descent start point B, which is the starting point of the helical cutting operation, is set at the same position as the machining start point A. Therefore, the turning center (helical center) O of the tool T in the helical cutting operation is set to a position shifted from the machining start point A (helical descent start point B) by the helical radius r input by the operator. Will be.

  Subsequently, the overcutting determination unit 15 determines whether or not the workpiece W is excessively cut in the helical cutting process based on the result of the intersection calculation, that is, the finish set inside the pocket shape PS in the helical cutting process. It is determined whether or not the allowance fa is scraped (whether or not the circular recess CH formed in the helical cutting process overlaps the finish allowance fa) (step S5). Here, when it is determined that the workpiece is not overcut, the program creation unit 16 creates a tool path based on the result of the intersection calculation performed by the overcutting determination unit 15 (step S8). This is converted into a machining program (step S9).

  In step S8, as shown in FIG. 4, after the tool T is positioned at the machining start point A (helical descent start point B) set at the center of the pocket shape PS, the machining start point A (helical descent start point) is set. From B), the tool T that immediately starts the helical cutting operation and returns to the helical descent start point B (machining start point A) at the end of the helical cutting operation is the machining start point A (helical descent start point B). Thus, a tool path is created so that cutting in the radial direction of the tool T is started along the pocket shape PS. In the tool path shown in the figure, the movement operation of the tool T is indicated by a dotted line, the helical cutting operation by the tool T is indicated by a solid line, and the cutting operation in the radial direction of the tool T is indicated by a one-dot chain line.

  On the other hand, if it is determined in step S5 that the workpiece is excessively cut as shown in FIG. 5 (a), the input helical radius r is set to the helical cutting step as shown in FIG. 5 (b). Is automatically corrected to the helical radius r1 so that the circular concave portion CH formed in step 1 is in contact with the inner edge of the finishing allowance fa (step S6), and the fact that the input helical radius r is not appropriate is automatically corrected. After the alarm is displayed at 13 (step S7), a tool path is created (step S8) and converted into a machining program (step S9).

  As described above, in this interactive machining program creation device 1, the helical descent start point B of the tool T is set at the same position as the machining start point A, so that it is created by the conventional machining program creation device. Unlike the machining program for pocket machining, there is no need to move the tool between the machining start point and the helical descent start point, and helical positioning can be started immediately after positioning to the machining start point. When the helical cutting is completed, the cutting in the radial direction of the tool can be started immediately. Therefore, the workpiece machining time is shortened, and the workpiece pocket machining can be efficiently performed in a short time.

  In addition, in the machining program created by the interactive machining program creation device 1, when the pocket machining of a workpiece is started, the tool T is first loaded as in the pocket machining machining program created by the conventional machining program creation device. Since it is positioned at the machining start point A set at the center of the pocket shape PS, when the operator first executes the machining program on a trial basis, there is a suspicion that the machining start point is wrong. There is no need to hold, and there is no need to check the processing start point.

  However, when the pocket machining is performed according to the machining program created by the interactive machining program creation device 1, the circular recess CH to be helically cut becomes the pocket machining according to the pocket machining machining program created by the conventional machining program creation device. As in the case of performing the process, it is not formed at the center of the pocket shape, and is formed in a state shifted to one side of the pocket shape PS, so that the frequency of excessive shaving increases, In the interactive machining program creation device 1, as described above, when the helical cutting is performed according to the helical radius r input by the operator, it is determined in advance whether or not excessive cutting occurs, and excessive cutting occurs. In this case, the input helical radius r is automatically corrected to an appropriate helical radius r1, and Is displayed on the display unit 13 so that the operator can recognize that proper machining cannot be performed with the input helical radius, and the operator can input a correction of the helical radius. It is possible to create an appropriate machining program without causing

  In the above-described embodiment, when the helical cutting is performed according to the helical radius r input by the operator, when excessive cutting occurs, the helical radius is automatically corrected to the appropriate helical radius r1. For example, an alarm is displayed to indicate that the input helical radius r is not appropriate, and the operator is not prompted to input the helical radius again, or the operator is requested to input the helical radius automatically. It may be determined.

  Also, if the helical radius is larger than the tool diameter, there may be uncut residue at the center of the circular recess CH formed by helical cutting, so make sure to check such uncut residue as well. When uncut parts are generated, it is desirable to automatically correct to an appropriate helical radius or to prompt the operator to input again.

  In the above-described embodiment, the interactive machining program creation device has been described. However, the present invention is not limited to this, and the present invention can be applied to various machining program creation devices. .

It is a functional block diagram showing one embodiment of a processing program creation device concerning this invention. It is a flowchart which shows a series of processes performed when the machining program creation apparatus same as the above creates a machining program for performing pocket machining on a workpiece. It is explanatory drawing for demonstrating the helical cutting process performed according to the machining program created by the machining program creation apparatus same as the above. It is a figure which shows the tool path of the pocket process created by the machining program creation apparatus same as the above. (A) is explanatory drawing for demonstrating the state in which excessive cutting generate | occur | produces in helical cutting, (b) is explanatory drawing for demonstrating the correction method in the case of automatically correcting a helical radius so that excessive cutting may not generate | occur | produce. It is. It is explanatory drawing for demonstrating the helical cutting process performed according to the machining program created by the conventional machining program creation apparatus. It is a figure which shows the tool path of the pocket process created by the machining program creation apparatus same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Interactive processing program creation apparatus 2 NC apparatus 11 Input part 12 Memory | storage part 13 Display part 14 Tool selection part 15 Overcutting judgment part 16 Program creation part 17 Control part 18 Interface W Work T Tool PS Pocket shape CH Circular recessed part A Machining start Point B Helical descent start point r Helical radius O Helical center

Claims (3)

A machining program creation device for automatically creating machining programs for NC machine tools,
By performing the helical cutting in the axial direction of the end mill, after forming a circular recess that contains a machining starting point of cutting in the radial direction of the end mill, the radial direction of the end mill from the machining start point of the circular inner recess When creating a machining program for pocket machining that performs machining, set the helical descent start point, which is the starting point of the helical cutting operation, to the machining start point of the cutting process in the radial direction of the end mill . A machining program creation device characterized by that.   When helical cutting is performed according to the input helical radius, it is determined whether or not overcutting occurs. If overcutting occurs, a notification is made that the input helical radius is not appropriate. The machining program creation device according to claim 1.   When helical cutting is performed according to the input helical radius, it is determined whether or not overcutting occurs. If overcutting occurs, the entered incorrect helical radius is set to an appropriate value that does not cause excessive cutting. The machining program creation device according to claim 1, wherein the machining program creation device automatically corrects the helical radius.

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