JP2006043836A - Machining condition setting method of machining tool, its machining condition setting program and record medium recording the machining condition setting program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably, simply and surely set the machining conditions including the rotational frequency of a tool and the feed speed of the tool for every machining path section by generating machining route information not to cause lowering of machining accuracy and lowering of durability of the tool, to shorten the time required for generating the machining route information and setting the machining conditions, and to realize compatibility between the machining accuracy and the machining efficiency. <P>SOLUTION: According to the work shape information and tool information before and after machining, in generating the machining route information of the tool to a work, one of a uniform machining pattern, a tip machining pattern and a side machining pattern is set as a machining pattern of causing the tool to come into contact with the work for each of machining route sections in which the tool comes into contact with the work and leaves it, and according to the machining pattern set for every machining route section, the rotational frequency of the tool is set to a lower rotational frequency in the side machining pattern than that in the uniform machining pattern in every machining route section, and the feed speed of the tool is set for every machining route section. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for automatically setting machining conditions including the number of rotations of a tool and a feed rate when a workpiece is cut by a machine tool.

  Conventionally, for machine tools for numerically controlled cutting (NC machine tools) such as when manufacturing dies, tool processing path information (tool trajectory) for the workpiece, tool rotation speed and feed speed NC data including the machining conditions including is created, and the machine tool is operated based on the NC data to cut the workpiece. During cutting, the cutting load of the tool often changes. For example, when cutting a workpiece with many free-form surfaces such as a die for press-molding the body of an automobile, the tool is mainly three-dimensional. A ball end mill capable of cutting is used, but the cutting load tends to change frequently.

  Here, the cutting load of the tool changes according to the contact area of the tool with the workpiece, the feed speed, the rotation speed, and the like. However, in Patent Document 1, the cutting load is not excessive when creating NC data. As described above, a technique is disclosed in which the contact area of a tool with respect to a workpiece is calculated based on the workpiece shape information and the tool information, and the feed speed of the tool is set based on the contact area. Also disclosed is a technique for obtaining a contact high probability position of a tool having the highest contact probability with respect to a workpiece and setting the number of rotations of the tool so that the average tool peripheral speed is obtained at the contact high probability position.

By the way, when creating NC data, especially in a machining area where the cutting depth is equal to or greater than the radius of the tool blade among the machining areas of the workpiece cut by the tool, a machining path for cutting the workpiece deeply stepwise. Thus, machining path information is generated.
JP 2003-256010 A

  As the contact state of the tool with respect to the workpiece, there is a state in which the blade of the tool is in contact with the workpiece symmetrically with respect to the center line of the blade edge, and a state in which it is in contact with the workpiece asymmetrically. The load of the tool becomes unstable, the tool is likely to bend and chatter, and the contact with the workpiece (biting) is poor. In a state where all of one side of the blade and only the vicinity of the tip on the opposite side are in contact with the workpiece, the above problem becomes more prominent.

  Therefore, when setting machining conditions including the number of rotations and feed speed of the tool for each machining path section from when the tool comes into contact with the workpiece until it leaves, especially for cutting workpieces with many free-form surfaces. When creating NC data, the contact state of the tool with the workpiece changes frequently, so that the machining accuracy is not lowered for each machining path section, and the durability of the tool is not lowered. It is difficult to set conditions appropriately and easily.

  In Patent Document 1, the contact area of the tool with respect to the workpiece is calculated based on the workpiece shape information and the tool information, and the tool feed speed is set according to the contact area so that the cutting load does not become excessive. The problem is not taken into consideration.

  For machining areas where the cutting depth is greater than or equal to the radius of the tool blade among the machining areas of the workpiece to be machined with the tool, machining path information is generated so that it becomes a machining path for deeply cutting the workpiece in stages. In particular, especially when creating NC data for machining a workpiece with many free-form surfaces, it is difficult to extract the machining area first, and as described above, the machining accuracy decreases. It is difficult to generate machining path information and to set machining conditions appropriately and simply so that the durability of the tool does not deteriorate.

  In other words, based on past machining results and the know-how and experience of NC data creators, especially when NC data is generated for cutting a workpiece with many free-form surfaces, the accuracy may be poor. Since it is difficult to judge whether the cost and machining conditions are optimal, NC data creation time increases, and the part that tends to be inaccurate and the countermeasures are unclear. Differences occur in the NC data created for each person, and high-precision NC cutting cannot be performed stably. Eventually, there is a possibility that a reworking period may occur, and the machining period becomes longer.

  An object of the present invention is to generate machining path information so as not to cause a reduction in machining accuracy and a decrease in tool durability, and set machining conditions including the rotation speed of the tool and the feed speed of the tool for each machining path section. Setting properly and easily, reducing the time required for generating machining path information and setting machining conditions, enabling both improvement of machining accuracy and machining efficiency, etc. .

  The machine tool machining condition setting method according to claim 1 is a method for setting machining conditions including a rotation speed and a feed speed of a tool when a workpiece is machined by a machine tool using an information processing device. When generating tool processing path information for a workpiece based on shape information and tool information, as a processing pattern in which the tool contacts the workpiece for each processing path section from when the tool contacts the workpiece until it leaves. An even machining pattern in which the tool blade is in contact with the workpiece evenly with respect to the cutting edge center line, a tip machining pattern in which only the tip of one side of the tool blade is in contact with the workpiece, and only near the side of one side of the tool blade The number of rotations of the tool for each machining path section based on the first step for setting one of the side machining patterns in contact with the workpiece and then the machining pattern set for each machining path section A second step for setting the side machining pattern to have a lower rotational speed than the uniform machining pattern, and a third step for setting the tool feed rate for each machining path section. It is characterized by.

  In this machine tool machining condition setting method, in the first step, when the machining path information of the tool for the workpiece is generated, the machining pattern is equal machining pattern, tip machining pattern, and side machining pattern for each machining path section. Is set. Here, the side machining pattern is more unstable than the uniform machining pattern, the load state of the tool becomes unstable, bending and chatter vibration are likely to occur, the contact with the workpiece (biting) is poor, and the machining accuracy is reduced. Easy to do. That is, in the second step, on the basis of the machining pattern set for each machining path section, for each machining path section, the rotation speed of the tool is lower than the uniform machining pattern for the side machining pattern. Thus, in the machining path section that becomes the side machining pattern, the occurrence of tool deflection and chatter vibration is suppressed, the contact with the workpiece is improved, and the machining accuracy is improved. In the machining path section where the uniform machining pattern is formed, the rotational speed of the tool can be maintained at a high rotational speed. In the third step, the feed rate of the tool is set using the rotation speed of the tool set in the second step so that the cutting load of the tool does not become excessive and the machining efficiency can be improved. be able to.

In the invention of claim 1, the following configuration can be adopted.
In the first step, when setting the machining pattern, based on the workpiece shape information before and after the machining and the tool information, the cutting depth of the machining area to be machined by the tool is greater than or equal to the radius of the tool blade. A machining area is extracted, point cloud data of this machining area is generated, and each machining path section is set based on the point cloud data (claim 2). In the third step, the feed speed is set so that the workpiece cutting amount per rotation of one blade of the tool becomes a preset cutting amount (Claim 3). The tool is a ball end mill.

  The processing condition setting program for a machine tool according to claim 5 is a program for causing an information processing device to execute processing for setting processing conditions including a rotation speed and a feed speed of a tool when a workpiece is cut by a machine tool. When generating tool machining path information for a workpiece based on workpiece shape information before and after machining and tool information, the tool contacts the workpiece for each machining path section from when the tool contacts the workpiece until it leaves. Machining patterns to be performed are a uniform machining pattern in which the tool blade is in contact with the workpiece evenly with respect to the center line of the blade edge, a tip machining pattern in which only the tip of one side of the tool blade is in contact with the workpiece, and one side of the tool blade The first routine for setting one of the side machining patterns in which only the part is in contact with the workpiece, and each machining pattern based on the machining pattern set for each machining path section. Second routine for setting the rotation speed of the tool for each path section so that the side machining pattern has a lower rotation speed than the uniform machining pattern, and then setting the feed speed of the tool for each machining path section And a third routine.

  The machine tool machining condition setting program is supplied to the information processing means via various communication means such as the Internet, and is recorded on various recording media such as a flexible disk and a CD and supplied to the information processing means. A processing condition setting program is started by the processing means, and first to third routines corresponding to the first to third steps of claim 1 are executed. In addition, the same effects as those of the first aspect are achieved.

  A recording medium storing a machining condition setting program for a machine tool according to a sixth aspect records the machining condition setting program according to a fifth aspect. The machining condition setting program recorded on the recording medium is supplied to the information processing means, and the machining condition setting program is started by the information processing means. In addition, the same effects as those of the first aspect are achieved.

  According to the machining condition setting method for a machine tool of claim 1, when generating machining path information of a tool for a workpiece in the first step, an equal machining pattern and a tip machining pattern as machining patterns for each machining path section. And the side processing pattern can be set. Here, from the verification results by the inventors of the present application, the side machining pattern is more unstable in the load state of the tool than the uniform machining pattern, and is liable to bend and chatter, and the contact with the workpiece is improved. It is known that the machining accuracy is likely to be deteriorated. Therefore, in the second step, the rotation speed of the tool for each machining path section based on the machining pattern set for each machining path section. Is set so that the side machining pattern has a lower rotational speed than the uniform machining pattern, thereby suppressing the occurrence of tool deflection and chatter vibration in the machining path section that becomes the side machining pattern. Can be improved and machining accuracy can be improved, and therefore the durability of the tool can be increased.

  Further, in the first step, it is possible not to set other machining patterns that have a lower machining accuracy than the uniform machining pattern, the tip machining pattern, and the side machining pattern. In the third step, the tool feed speed can be set so that the cutting load of the tool does not become excessive and the machining efficiency can be increased by using the rotation speed of the tool set in the second step. . In this way, machining path information is generated and machining conditions including the number of rotations of the tool and the feed speed of the tool are appropriately and easily set for each machining path section so that the machining accuracy and the tool durability are not lowered. The time required for generating machining path information and setting machining conditions can be shortened. Eventually, it becomes possible to achieve both improvement in machining accuracy and machining efficiency.

  According to the machining condition setting method for a machine tool according to claim 2, when the machining pattern is set in the first step, the machining area to be cut by the tool is determined based on the workpiece shape information before and after the machining and the tool information. The machining area where the cutting depth is greater than the radius of the tool blade is extracted, point cloud data for this machining area is generated, and each machining path section is set based on this point cloud data. Machining path information of this machining area so that the machining area where the length is larger than the radius of the tool blade can be automatically extracted easily, and the machining accuracy and tool durability are not reduced. Can be reliably generated, and appropriate machining conditions corresponding to any of the uniform machining pattern, the tip machining pattern, and the side machining pattern can be easily and reliably set.

  According to the machining condition setting method for a machine tool of claim 3, in the third step, the feed speed is set so that the workpiece cutting amount per rotation of one blade of the tool becomes a preset cutting amount. Therefore, the cutting load of the tool can be made the same as a whole, and the cutting load of the tool can be stabilized and the durability can be increased while improving the processing efficiency.

  According to the machining condition setting method for a machine tool of claim 4, since the tool is a ball end mill, even when a workpiece having many free curved surfaces such as a die for press-molding an automobile body is reliably cut, In one step, for each machining path section, any of the uniform machining pattern, the tip machining pattern, and the side machining pattern can be reliably set as the machining pattern.

  According to the machining condition setting program for a machine tool of claim 5, since the first to third routines corresponding to the first to third steps of claim 1 are provided, the machining condition setting program for the machine tool is stored on the Internet. Can be supplied to the information processing means via various communication means such as, and can be recorded on various recording media such as a flexible disk and a CD and supplied to the information processing means. The processing condition setting program can be started by the information processing means. The effect similar to that of the first aspect is achieved.

  According to the recording medium recorded with the machining condition setting program for the machine tool according to claim 6, the machining condition setting program recorded on the recording medium can be supplied to the information processing means. The program is activated to achieve the same effect as that of the first aspect.

  The machine tool machining condition setting method according to the present invention is based on the workpiece shape information before and after machining and the tool information, and generates the machining path information of the tool for the workpiece. For each machining path section, as the machining pattern in which the tool contacts the workpiece, the uniform machining pattern in which the tool blade contacts the workpiece evenly with respect to the center line of the cutting edge, and only the vicinity of the tip on one side of the tool blade contacts the workpiece. Based on the first machining step and the machining pattern set for each machining path section, the first step of setting any one of the side machining pattern in which only the vicinity of one side of the blade of the tool is in contact with the workpiece The second step of setting the rotation speed of the tool for each machining path section so that the side machining pattern has a lower rotation speed than the uniform machining pattern, and then the tool rotation speed for each machining path section. Ri is obtained by a third step of setting the speed.

  FIG. 1 is a configuration diagram of a system for manufacturing a mold as a product by cutting a workpiece 2. In this system, an NC machine tool 1 for cutting a workpiece W and a NC machine tool 1 are supplied. There are provided a CAD system 2 (computer-aided design system 2) and a CAM system 3 (computer-aided production system 3) for creating NC data.

  In the CAD system 2, shape data (work shape information, product shape information) is created from the model of the workpiece W and the mold. In the CAM system 3, shape data created by the CAD system 2 (work shape information before and after machining). Based on the tool information, the machining path information of the tool 5 with respect to the workpiece W is generated, and at that time, the rotation speed of the tool 5 is determined for each machining path section from when the tool 5 comes into contact with the workpiece W and leaves. Machining conditions including a feed rate are set, and NC data including the machining path information and machining conditions is created. In the NC machine tool 1, a ball end mill is used as the tool 5, which operates based on the NC data created by the CAM system 3 to cut the workpiece 2. The CAM system 3 corresponds to an information processing apparatus.

FIG. 2 is a diagram showing a flow of processing executed by the CAM system 3.
In the CAM system 3, the calculation processing (S 1) of the machining path information of the tool 5 for the workpiece W is performed based on the workpiece shape information (CAD data) and the tool information fetched from the CAD system 2, and then this machining is performed. A path information editing process (S2) is performed, and then an interference check process (S3) between the tool 5 (tool holder and spindle) and the workpiece 2 when the tool 5 is moved along the machining path is performed. Done. In the interference check process, for example, the tool 5 can be moved on the display screen to check the interference. Here, pre-rough machining path generation area processing (S4) is performed based on workpiece shape information before and after machining and tool information obtained in the interference check process.

Next, the pre-rough machining path generation area process of S4 will be described based on the flowchart of FIG. 3 (Si (i = 10, 11, 12,... Indicates each step)).
When the pre-rough machining path generation area process is started, first, workpiece shape information before and after machining is read (S10), and then a machining area Wb (that is, machining allowance) of the workpiece W to be cut by the tool 5 is obtained. The workpiece shape information before and after machining is compared and calculated (S11). Next, all point data (three-dimensional (x, y, z)) of the machining area Wb calculated in S11 is extracted (S12), and the all point data is opened (S13).

  Next, among the opened point data, z values of a plurality of point data having the same x and y values are read (S14). Here, in S14, the z value is read in ascending order (the cutting depth is shallow). Next, when the read data is not a file end (S15; No), the cutting depth d is calculated from the z value read in S14 (S16). Next, it is determined whether or not the cutting depth d is greater than or equal to the radius r of the tool 5 (S17). If the cutting depth d is smaller than the radius r (S17; No), the process proceeds to S14, and then read. S14 to S17 are repeatedly executed until the data becomes a file end or the cutting depth d becomes equal to or larger than the radius r.

  Thereafter, when the cutting depth d is equal to or larger than the radius r (S17; Yes), the point data including the latest z value read in S14 is written (S18). Thereafter, it is determined whether or not the processing for all point data having the same x and y values has been completed (S19). If not completed (S19; No), the process proceeds to S14, and if completed (S19; Yes), S20. Migrate to If the read data is a file end (S15; Yes), the process proceeds to S20. In S20, all the point data written in S18 are read. In S21, machining path surface information of the tool 5 is created from the point data group, and the process returns.

  Based on the machining path surface information created in this way, as shown in FIG. 2, in the machining path information calculation process of S <b> 1, the cutting depth d of the tool 5 in the machining area of the workpiece W to be cut by the tool 5 is Machining path information including a machining area Wb that is greater than or equal to the radius r of the blade 5a is calculated. Thereafter, the processing path information editing process in S2 is performed, and the interference check process in S3 is performed. If the machining allowance is greater than or equal to the radius d of the tool 5 from the workpiece shape information before and after this stage, again, The pre-rough machining path generation area process of S4 is performed, then the post process (S5) is performed, the machining conditions are set (S6), and then the NC including the machining path information and the machining conditions is performed in S7. Data is created.

  Here, with respect to the machining pattern in which the tool 5 comes into contact with the workpiece W, as shown in FIG. 4, (a) a side machining pattern in which only the vicinity of one side of the hemispherical blade 5a of the tool 5 is in contact with the workpiece W (B) A tip machining pattern in which only the tip of one side of the blade 5a of the tool 5 is in contact with the workpiece W, and (c) an uniform machining pattern in which the blade 5a of the tool 5 is in contact with the workpiece W evenly with respect to the center line of the cutting edge. , (D) All of one side of the blade 5a of the tool 5 and other machining patterns in which only the vicinity of the tip on the opposite side is in contact with the workpiece W are classified into four types of machining patterns.

  Regarding the load state of the tool 5, the case of the uniform machining pattern of (c) is most stable, the case of the side machining pattern of (a) and the tip machining pattern of (b) is stable, and the others of (d) In the case of this processing pattern, it becomes the most unstable. That is, the machining accuracy is the highest in the uniform machining pattern of (c), and is slightly reduced in the side machining pattern of (a) and the tip machining pattern of (b), but by lowering the rotation speed of the tool 5 I can deal with it. However, in the other machining pattern (d), the tool 5 is likely to be bent and chatter vibration, the contact property (biting) with the workpiece W is poor, and the machining accuracy tends to be lowered.

  Then, when the machining path information is generated by performing the machining path information calculation process of S1 and the editing process of the machining path information of S2 based on the workpiece shape information before and after the machining and the tool information, the tool 5 For each machining path section from the time when the tool 5 comes into contact with the workpiece W, any one of the machining patterns (a) to (c) is set as the machining pattern in which the tool 5 comes into contact with the workpiece W. That is, (a) Machining path information is generated so as to be any one of the machining patterns of (c) to (c).

  As shown in FIG. 5, for example, when forming a recess Wa in the workpiece W in order to manufacture a mold for forming a rib on a molded product, the workpieces before and after processing are performed by executing the processing of S1 to S4. Based on the shape information and the tool information, a machining area Wb in which the cutting depth d is greater than or equal to the radius r of the blade 5a of the tool 5 is extracted from the machining area cut by the tool 5, and the point of the machining area Wb is extracted. Group data is generated, and based on this point group data, each machining path section from when the tool 5 comes into contact with the workpiece W until it leaves is set, and each machining path section has a machining pattern as a side of (a). One of the partial machining pattern, the tip machining pattern (b), and the uniform machining pattern (c) is set. Such a process corresponds to the first step. In addition, in the recessed part Wb where the width | variety of cutting depth becomes narrow gradually, the tool 5 used as a gradually small diameter will be used.

  As shown in FIG. 6, for example, when forming a recess Wa in the workpiece W in order to manufacture a mold for forming a rib on a molded product, nine machining path sections A11 to A13, A21 to A23, A311 A33 is set, and the tool 5 moves in the order of the upper machining path sections A11 to A13, the middle machining path sections A21 to A23, and the lower machining path sections A31 to A33, and the recesses Wa are formed. Any one of the machining patterns (a) to (c) can be reliably set by appropriately setting the order of movement of the plurality of machining path sections.

  That is, as shown in FIG. 7, by first moving the tool 5 along the upper intermediate machining path section A12, the machining path section A12 has the uniform machining pattern (c), and then the machining path. By moving the tool 5 along the machining path sections A11 and A13 on both sides of the section A12, the side machining pattern (a) is obtained in the machining path sections A11 and A13. The same applies to the machining path sections A21 to A23 and A31 to A33 in the middle and lower stages. The number of rotations of the tool 5 is set to, for example, 2000 rpm in the case of the uniform machining pattern (c), and to 1400 rpm, for example, in the case of the side machining pattern of (a).

Next, the processing condition setting process of S6 will be described in detail based on the flowchart of FIG. 8 (Si (i = 30, 31, 32... Indicates each step)). The processing condition setting process includes the second and third steps.
When the machining condition setting process is started, first, NC data including the machining path information and tool information generated in S1 to S4 is extracted (S30).

  Next, a set one-blade cutting amount is calculated from a predetermined standard die material, hardness, and tool L / D (tool protruding length / diameter) (S31). Here, with respect to the cutting amount VB per cutting blade, the coefficient corresponding to the tool 5 to be used among the coefficient V1 for the material of the workpiece W, the coefficient V1 for the hardness, and several coefficients determined stepwise for the L / D of the tool From V2, a cutting amount V per rotation of one cutting blade of the tool 5 (= VB × V1 × V2, hereinafter also referred to as a designated volume or a set one-blade volume V) is calculated. The predetermined cutting amount VB and the coefficients V1 and V2 are set to optimum values from the viewpoint of tool life and machining time.

  Next, the NC data is opened (S32), and then one line of NC data is read (S33). Next, it is determined whether or not it is the file end, that is, the final data of the NC data (S34). If it is not the file end (S34; No), one component point is divided (S35). In this way, each tool path constituted by one component point is divided into a plurality of sections, and the tool trajectory from when the tool contacts the workpiece 2 until it leaves is divided into a number of sections. For example, as shown in FIG. 9, a short division length is set in the vertical movement section and divided into P1 → P12-1 → P12-2 →... → P2, and a longer division length is provided in the sections other than the vertical movement. It is set and divided into P1 → P12-1 → P2.

  Next, of the material shape data, shape data in a necessary range is read (S36). Specifically, it is determined whether or not the shape data range (XY coordinates) used for the calculation exceeds the use memory. If it is over, unnecessary shape data is written. For example, as shown in FIG. 10, the shape data of the workpiece material shape is read only as the range of the shape data necessary for the calculation. In this way, it becomes easy to add element map information to the memory in addition to the header information, and the Z coordinate value can be extracted efficiently.

  Next, it is determined whether arc or Nurbs (Non-Uniform Rational B-Spline) interpolation is necessary (S37). When the circular arc or Nurbs interpolation is required (S37; Yes), the section is further divided by the designated tolerance value (S38). In other words, in arc and Nurbs interpolation, the curve section is approximated by a polygonal line section connecting dividing points with straight lines, and a volume (cutting amount) calculation is facilitated by forming a set of a plurality of straight line sections. . After S38, or when arc or Nurbs interpolation is not required (S37; Yes), the number of rotations of the tool 5 is determined from the tool contact position for each component point (S39).

  That is, for each machining path section from when the tool 5 comes into contact with the workpiece W until the tool 5 leaves, any of the uniform machining pattern, the tip machining pattern, and the side machining pattern is selected as the machining pattern with which the tool 5 comes into contact with the workpiece. Based on this machining pattern, the number of rotations of the tool 5 is determined for each component point (S39). In this case, the rotational speed of the tool 5 is set so that the side machining pattern and the tip machining pattern have a lower rotational speed than the uniform machining pattern. For example, in the case of a uniform processing pattern, it is 2000 rpm, and in the case of a side processing pattern and a tip processing pattern, it is 1400 rpm. Thereafter, in the case of a file end (S34; Yes), NC data is read every G00 (S41), the rotation speed is selected as a processing condition, and the rotation speed for each G00 section is set (S42). The number of rotations is written (S43).

  Next, one line of NC data is read (S44), and then it is determined whether or not it is a file end, that is, the last data of the NC data (S45). If it is not a file end (S45; No), it is determined whether or not it is a designated code (S46). The designation code is data indicating that the NC data is coordinate data, and is, for example, a linear approximation code G1, a circular interpolation code G2, G3, or a NURBS interpolation code G6.2. The NC data that is the designation code is coordinate data of the constituent points (●) illustrated in FIG. 11, and a pair of adjacent constituent points constitutes one tool path section.

  If it is not a designated code (S46; No), if it is NC data such as a comment that is not a designated code, it is written as it is (S47), and the process returns to S44.

  If it is not the designation code (S46; No), it is determined whether or not the tool 5 is vertically moved (S48). That is, it is determined whether or not the tool path is a vertical movement section in which the tool 5 is moved forward in a direction perpendicular to the machining surface of the workpiece 2. As exemplified in S35, in the case of vertical movement (S48; Yes), the division length for vertical movement is set (S49). In the case of no vertical movement (S48; No), the division length other than for vertical movement is set. It is set (S50). After S49 or S50, one component point is divided (S51). Each tool path constituted by one constituent point is divided into a plurality of sections, and the tool trajectory from when the tool comes into contact with the workpiece 2 until it leaves is divided into a plurality of sections.

  Next, as exemplified in S36, the shape data in the necessary range is read from the material shape data (S52), and then, arc and Nurbs (Non-Uniform Rational B-Spline) interpolation is performed as in S37 to S39. Is necessary (S53; Yes), the section is further divided by the specified tolerance value (S54), and after S54 or after the arc or Nurbs interpolation is performed. If it is not necessary (S53; Yes), then the machining volume X of one section is calculated (S55). Here, the machining volume (required cutting amount) X of one divided section is calculated based on the tool path and the shape data of the material shape. As shown in FIG. 12, in an inclined section where there is a difference in height between the start point and the end point, it is divided into steps as shown in FIG. 13, and the Z coordinate value of the material shape of each step Wb and the Z coordinate after processing are divided. The difference from the value is multiplied by the plane area of each stage Wb, and the machining volume X is approximated by the sum of these.

Next, the NC data is changed to shape data after cutting (after processing) (S56). The changed shape data becomes data for setting the feed rate when cutting the tool path with another tool. Next, the rotation speed is changed for each G00 section (S57). Next, a feed rate F at which one blade becomes a specified volume is obtained (S58). In this case, V: setting 1 blade volume (mm ³ ), S: rotational speed (rpm), E: blade number (sheets), L: section length (mm), X: machining volume per section (mm ³⁾ ), F = V × S × E × L / X. Next, it is determined whether or not the calculated F value <the MAX value (S59).

  If the calculated F value <the MAX value is not satisfied (S59; No), that is, if the calculated F value is greater than or equal to the MAX value, the calculated F value is set to the MAX value (S60). This limits the feed speed F from the viewpoint of the durability of the tool or the specifications of the NC machine tool 1. After S60 or when the calculated F value <MAX value (S59; Yes), next, the feed deceleration in the vertical movement section is set (S61). Accordingly, in the vertical movement section, the feed speed F is decelerated and corrected at each of the above-described divided positions, so that the feed speed F gradually decreases. Therefore, the tool thrusts perpendicularly to the machining surface of the workpiece 2 at a high speed. Can be avoided.

  Next, it is determined whether or not the calculated F value> MIN value (S62). When the calculated F value> MIN value is not satisfied (S62; No), that is, when the calculated F value is equal to or smaller than the MIN value, the calculated F value is set to the MIN value (S63). This is because if the feed speed F is too slow, the NC machine tool 1 may vibrate. After S63 or if the calculated F value> MIN value (S62; Yes), then the F value change rate with respect to the previous F value is calculated (S64). Next, the F value maintenance range (set value) is read (S65), and it is determined whether the F value change rate is within the F value maintenance range (S66). When the F value change rate is within the F value maintenance range (S66; Yes), the F value is set to (maintain) the previous value (S67), and when the F value change rate is not within the F value maintenance range. (S66; No), the F value is set to the calculated F value (S68).

  Here, the feed speed F is corrected and replaced in relation to the feed speed F given to the previous section. That is, as shown in FIG. 14, when the feed speed given to the previous section P0 → P1 is F0 and the feed speed calculated for the section P1 → P2 is FC, the rate of change K = ΔF01 / F0 When (ΔF01 = F0−FC) is equal to or larger than the predetermined value Ko, the calculated value FC is given as the feed speed F1 of the section. When the calculated value FC is smaller than the predetermined value Ko, one is set as the feed speed F1 of the section. The feed speed F0 of the previous section is given. As a result, it is possible to perform stable machining while avoiding complicated feed rate control and awkward machine movement.

The predetermined value Ko increases as the feed speed F0 given for the previous section P0 → P1 increases. As a result, at locations where the feed rate F is high (locations where the cutting load is low), even if the feed rate F is slightly different from the required value, the cutting load will not change significantly, so this will be ignored. Since the fluctuation of the speed F is prevented, it is advantageous for ensuring the stability of processing. On the other hand, at locations where the feed rate F is low (locations where the cutting load is high), the feed rate F is finely controlled in response to changes in the feed rate F obtained by calculation. A load can be avoided. S58 to S69 correspond to the third step.

  After S67 or S68, the feed value of one component point section is stored (S69). Next, NC data for each specified code is written (S70), and the process returns to S44. A G code is assigned between each component point, and NC data including data on the feed rate F of the tool is written for each G code. At this time, NC data that is not coordinate data is also written. Thereafter, in the case of a file end (S45; Yes), post-cutting shape data is written (S71), and finally the NC data is closed (S72), and the process ends.

According to the machining condition setting method of the machine tool described above, the following operations and effects are achieved.
When generating the machining path information of the tool 5 with respect to the workpiece W, any one of an equal machining pattern, a tip machining pattern, and a side machining pattern can be set as a machining pattern for each machining path section. Here, from the verification results by the inventors of the present application, the side machining pattern is more unstable in the load state of the tool than the uniform machining pattern, and is liable to bend and chatter, and the contact with the workpiece is improved. It is known that the machining accuracy is likely to be deteriorated. Therefore, based on the machining pattern set for each machining path section, the number of rotations of the tool 5 is equalized for each machining path section. By setting the side machining pattern to have a lower rotational speed than the side machining pattern, the bending of the tool and chatter vibration are suppressed in the machining path section that becomes the side machining pattern, and the contact with the workpiece is improved. It is possible to improve the processing accuracy, and therefore to increase the durability of the tool.

  In addition, it is possible to avoid setting other machining patterns with lower machining accuracy than the uniform machining pattern, the tip machining pattern, and the side machining pattern. Then, using the rotation speed of the tool set as described above, the feed rate of the tool can be set so that the cutting load of the tool does not become excessive and the machining efficiency can be improved. In this way, machining path information is generated and machining conditions including the number of rotations of the tool and the feed speed of the tool are appropriately and easily set for each machining path section so that the machining accuracy and the tool durability are not lowered. The time required for generating machining path information and setting machining conditions can be shortened. Eventually, it becomes possible to achieve both improvement in machining accuracy and machining efficiency.

  When setting the machining pattern, based on the workpiece shape information before and after machining and the tool information, a machining area in which the cutting depth is equal to or greater than the radius of the blade 5a of the tool 5 is extracted from the machining area cut by the tool. Since the point cloud data of this machining area is generated and each machining path section is set based on this point cloud data, the machining area where the cutting depth is not less than the radius of the blade 5a of the tool 5 is automatically selected. The machining path information of this machining area can be generated with certainty so that it can be easily extracted and the machining accuracy and tool durability are not lowered. Appropriate machining conditions corresponding to any of the machining patterns can be set easily and reliably.

  Since the feed rate is set so that the workpiece cutting amount per rotation of one blade of the tool becomes a preset cutting amount, the cutting load of the tool 5 can be made the same overall, and the processing efficiency It is possible to stabilize the cutting load of the tool and increase the durability while increasing the resistance. Since the tool 5 is a ball end mill, even when a workpiece having many free-form surfaces, such as a die for press-molding the body of an automobile, is reliably cut, a uniform machining pattern and a tip as a machining pattern for each machining path section Either the processing pattern or the side processing pattern can be set reliably.

  Here, a program for causing the information processing apparatus (CAM system 3) to execute processing for setting processing conditions including the rotation speed and feed speed of the tool 5 when the workpiece W is cut by the NC machine tool 1, that is, When generating tool machining path information for a workpiece based on workpiece shape information before and after machining and tool information, the tool contacts the workpiece for each machining path section from when the tool contacts the workpiece until it leaves. Machining patterns to be performed are a uniform machining pattern in which the tool blade is in contact with the workpiece evenly with respect to the center line of the blade edge, a tip machining pattern in which only the tip of one side of the tool blade is in contact with the workpiece, and one side of the tool blade Each machining path section based on the first routine for setting any one of the side machining patterns in contact with the workpiece only in the vicinity of the section, and then the machining pattern set for each machining path section. A second routine for setting the rotation speed of the tool so that the side machining pattern has a lower rotation speed than the uniform machining pattern, and then the second routine for setting the feed speed of the tool for each machining path section. The processing condition setting program having three routines can be supplied to the information processing means via various communication means such as the Internet, and can be recorded on various recording media such as a flexible disk and a CD and supplied to the information processing means. The processing condition setting program is activated by the information processing means, and the same effects as described above are obtained.

  When setting the number of rotations of the tool, the tip machining pattern and the side machining pattern are set to different rotation numbers in addition to setting the tip machining pattern and the side machining pattern to the same number of revolutions as in the above-described embodiment. You may make it do. In addition, various modifications can be added without departing from the spirit of the present invention.

It is a block diagram which shows the structure of the control apparatus of the machine tool which concerns on embodiment of this invention. It is a flowchart figure which shows the flow of a process in a CAM system. It is a flowchart of a prior rough machining path generation area process. It is a figure which shows the classified processing pattern. It is explanatory drawing in the case of cutting the hole part of a workpiece | work with a tool. It is a figure which shows the tool path | route in the case of FIG. It is a figure which shows the processing pattern and rotation speed of the tool in the case of FIG. It is a flowchart of the process for setting process information. It is explanatory drawing which shows the division | segmentation aspect of the vertical movement area and other movement area of a tool. It is a figure which shows a part of area map. It is explanatory drawing which shows a tool and NC data composition point. It is a figure which shows a part of shape data of the embodiment. It is explanatory drawing of the calculation method of the processing volume (required cutting amount) of an inclination part. It is explanatory drawing of correction | amendment of the feed speed F of the embodiment.

Explanation of symbols

W Work 1 NC machine tool 3 CAM system 5 Tool (ball end mill)
5a blade

Claims (6)

In a method of setting a machining condition including a rotation speed and a feed rate of a tool when cutting a workpiece by a machine tool using an information processing device,
When generating tool machining path information for a workpiece based on workpiece shape information before and after machining and tool information, the tool contacts the workpiece for each machining path section from when the tool contacts the workpiece until it leaves. Machining patterns to be performed are a uniform machining pattern in which the tool blade is in contact with the workpiece evenly with respect to the center line of the blade edge, a tip machining pattern in which only the tip of one side of the tool blade is in contact with the workpiece, and one side of the tool blade A first step of setting one of side machining patterns in which only the vicinity of the part contacts the workpiece;
Next, based on the machining pattern set for each machining path section, the rotation speed of the tool is set for each machining path section so that the side machining pattern has a lower rotation speed than the uniform machining pattern. The second step;
Next, a third step of setting a tool feed rate for each machining path section;
A machining condition setting method for a machine tool, comprising:   In the first step, when setting the machining pattern, based on the workpiece shape information before and after the machining and the tool information, the cutting depth of the machining area to be machined by the tool is greater than or equal to the radius of the tool blade. 2. A machining condition setting method for a machine tool according to claim 1, wherein a machining area is extracted, point cloud data of the machining area is generated, and each machining path section is set based on the point cloud data. .   The feed rate is set in the third step so that the workpiece cutting amount per rotation of one blade of the tool becomes a preset cutting amount. How to set machining conditions for machine tools.   The machine tool machining condition setting method according to claim 1, wherein the tool is a ball end mill. In a program for causing an information processing device to execute processing for setting processing conditions including the rotational speed and feed rate of a tool when cutting a workpiece with a machine tool,
When generating tool machining path information for a workpiece based on workpiece shape information before and after machining and tool information, the tool contacts the workpiece for each machining path section from when the tool contacts the workpiece until it leaves. Machining patterns to be performed are a uniform machining pattern in which the tool blade is in contact with the workpiece evenly with respect to the center line of the blade edge, a tip machining pattern in which only the tip of one side of the tool blade is in contact with the workpiece, and one side of the tool blade A first routine for setting one of the side machining patterns in which only the vicinity of the part contacts the workpiece;
Next, based on the machining pattern set for each machining path section, the rotation speed of the tool is set for each machining path section so that the side machining pattern has a lower rotation speed than the uniform machining pattern. A second routine;
Next, a third routine for setting the feed rate of the tool for each machining path section;
A machine tool machining condition setting program characterized by comprising: 6. A recording medium recording a machining condition setting program for a machine tool, wherein the machining condition setting program according to claim 5 is recorded.