Mold processing method

Abstract

To provide a die machining method that can reduce a time for machining an unmachined corner part.SOLUTION: A die machining method includes a rough machining step, an unmachined part-cutting step for cutting an unmachined corner part of a molded concave part. A cutting tool that is used in the unmachined-part cutting step is a solid end mill whose tool diameter is one third of a tool diameter of a cutting tool for rough machining. The unmachined-part cutting step includes a first side surface cutting step in which a side surface is cut in an axial direction by a first cutting-in quantity using the solid end mill to cut the unmachined corner part, and a second side-surface cutting step in which the surface machined in the first side-surface cutting step is cut with the sold end mill with the second cutting-in quantity smaller than the first cutting-in quantity while moving the solid end mill in the opposite direction of a machining depth-direction are executed repeatedly throughout a depth direction of the corner part by a first cutting-in quantity.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a method for processing a mold.

Background Art

[0002] Conventionally, a method for processing the remaining cut at the corner of a mold generated by a roughing process has been studied. As one of the methods for cutting the remaining cut at the corner, by performing contour machining multiple times while gradually reducing the tool diameter, the remaining cut corner is gradually reduced without excessively reducing the machining efficiency, and finally the remaining cut is reduced to a size that does not affect the next process.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, Patent Document 1 discloses a flowchart in which contour machining is performed on the remaining cut at the corner and repeated until the remaining cut reaches a desired size.

[0005] However, in the processing method disclosed in Patent Document 1, contour machining is performed multiple times with multiple tools on the remaining cut at the corner. Therefore, in addition to the cutting time, tool change time is also required, so the processing time for the remaining cut corner is very long.

[0006] Therefore, in view of the above problems, the present invention aims to provide a processing method capable of shortening the processing time and the process by using one type of cutting tool in the processing step of reducing the remaining cut at the corner.

Means for Solving the Problems

[0007] According to one aspect of the present invention, there is provided a method for machining a mold, the method including a rough machining step of cutting a metal material to roughly machine a formed recess, and a remaining cutting step of cutting a remaining portion of a corner of the formed recess after the rough machining. The cutting tool used in the remaining cutting step is a solid end mill having a tool diameter that is 1 / 3 or less, preferably 1 / 4 or less, more preferably 1 / 5 or less, of the cutting tool for rough machining. The remaining cutting step includes a first side cutting step of cutting the remaining portion of the corner by side cutting in the axial direction with at least one of an outer peripheral edge and an arc edge of the solid end mill with a first cutting depth (n1), and a second side cutting step of cutting the surface machined in the first side cutting step with the solid end mill while moving the solid end mill in a direction opposite to the machining depth direction under a condition that a cutting depth in the axial direction is a second cutting depth (n2) smaller than the first cutting depth (n1). The steps are repeatedly executed over the depth direction of the corner.

[0008] According to the above configuration, by simply performing the first side cutting step and the second side cutting step alternately from top to bottom on the remaining portion of the corner once, the remaining portion can be made sufficiently small. This is because the tool diameter of the cutting tool used in the first side cutting step and the second side cutting step is very small, being 1 / 3 or less of the cutting tool used in the rough machining step, so that the tool can enter up to the corner in one step. In addition, since the second cutting depth is smaller than the first cutting depth, the remaining portion generated in the first side cutting step can be made smaller in one step by the second side cutting step to a size that does not have an adverse effect on the next step.

[0009] Furthermore, when the tool diameter of a cutting tool is usually small, the depth of cut also becomes small, resulting in a longer machining time. However, the present invention can achieve an effect by performing a large depth of cut in the first side cutting process and side cutting the remainder of the first process in the second side cutting process. Therefore, compared with the conventional contour machining in which machining is performed multiple times while gradually reducing the tool diameter, the remaining material can be reduced to a desired size in a machining time equal to or less than the conventional method. Furthermore, since tool change is not required, there is no need to hold a plurality of tools, and the setup and time for tool change are also unnecessary.

[0010] The solid end mill is a ball end mill, and the first depth of cut in the first side cutting process may be a length of 0.8 times or more and 1.5 times or less the ball diameter of the solid end mill.

[0011] The solid end mill is a ball end mill, and the second depth of cut in the second side cutting process may be 0.2 times or more and 1.2 times or less the ball radius of the solid end mill.

[0012] The solid end mill is a radius end mill, and the first depth of cut in the first side cutting process may be a length of 0.5 times or more and 0.9 times or less the edge length of the solid end mill, and preferably 0.7 times or more.

[0013] The solid end mill is a radius end mill, and the first depth of cut in the first side cutting process may be a length of 0.8 times or more and 1.5 times or less the tool diameter of the solid end mill.

[0014] The solid end mill is a radius end mill, and the second depth of cut in the second side cutting process may be 0.8 times or more and 1.5 times or less the corner R of the solid end mill.

[0015] The tool diameter of the solid end mill may be not less than 1 times and not more than 1.6 times the tool diameter of the cutting tool for final finishing of the corner portion.

[0016] The method may be such that the inclination angle of the corner portion of the formed recess is not less than 30° and less than 90°.

[0017] In the present invention, in the first side cutting process, the outer peripheral edge is mainly used to reduce the remaining material at the corner. Therefore, when the inclination angle of the corner is less than 30°, the outer peripheral edge cannot be effectively used, and the effects of the present invention cannot be fully exerted. Further, the cutting tool is attached to the spindle of the machine tool via a tool holder. There are tool holders with a taper angle, and those of a slightly slender slim type, etc., but the upper limit of the inclination angle of the corner needs to take into account the shape and protruding length of the tool holder, so it must be less than 90°.

Advantages of the Invention

[0018] According to one aspect of the present invention, there is provided a method for machining a mold that can shorten the machining time of the remaining corner portion.

Brief Description of the Drawings

[0019]

Figure 1

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Figure 10

Figure 11

Figure 12

Embodiment for Carrying Out the Invention

[0020] FIG. 1 is a schematic view of the die processing apparatus 10 with the metal material W installed. FIG. 2 is a partial perspective view showing an example of the die. The die processing apparatus 10 of the present embodiment includes a cutting tool 11, a spindle 12, a tool holder 14, a metal material holder 15, a stage 13 that supports the metal material W via the metal material holder 15, and a control unit 16.

[0021] For each step in the die processing method, a cutting tool of an appropriate type is used for the cutting tool 11. In the processing method of the present embodiment described later, in the first side cutting step and the second side cutting step, a solid end mill having a cutting edge portion at the tip of the cutting tool is used. The solid end mill used in the processing method of the embodiment is a radius end mill, a square end mill, or a ball end mill. Further, the cutting tool used in the cutting steps other than the first side cutting step and the second side cutting step is not limited to a solid end mill and is determined by the processing shape and processing conditions.

[0022] The cutting tool 11 is held by the spindle 12 via the tool holder 14. Further, the spindle 12 includes a drive mechanism that rotationally drives the cutting tool 11 around the tool center axis, and a movement mechanism that moves the cutting tool 11. The movement mechanism of the spindle 12 enables the cutting tool 11 to move in the three axial directions of the X-axis, Y-axis, and Z-axis. Also, in this embodiment, the movement mechanism of the spindle only needs to have the aforementioned three axes, and for example, the movement mechanism may have functions of three or more axes such as tilting the spindle 12 itself.

[0023] The stage 13 supports the metal material W from below via the metal material holder 15. The metal material holder 15 includes a fixing mechanism for fixing the metal material W and an attitude control mechanism for adjusting the attitude of the metal material W. The fixing mechanism and the attitude control mechanism of the stage 13 are provided as needed, respectively.

[0024] The control unit 16 comprehensively controls the die processing apparatus 10. The control unit 16 is a computer capable of executing a die processing program. The control unit 16 includes a tool control unit 17 that controls the spindle 12, a stage control unit 18 that controls the stage 13, and a storage unit 19 connected to the tool control unit 17 and the stage control unit 18. The tool control unit 17 and the stage control unit 18 are realized by the CPU of the control unit 16 executing an operation program stored in the storage unit 19.

[0025] The control unit 16 rotationally drives the cutting tool 11 and moves the cutting tool 11 in the X-axis direction, Y-axis direction, and Z-axis direction by controlling the spindle 12 via the tool control unit 17. The control unit 16 holds the metal material W in a predetermined attitude by controlling the fixing mechanism and the attitude control mechanism of the metal material holder 15 via the stage control unit 18. The die processing apparatus 10 executes cutting processing of the metal material W using the cutting tool 11 based on a processing program under the control of the control unit 16. Hereinafter, a case where a forming recess 101 that opens upward as shown in FIG. 2 is formed in the metal material W using the die processing apparatus 10 will be described.

[0026] FIG. 3 is a flowchart of the die processing method according to this embodiment. As shown in FIG. 3, the mold processing method of this embodiment includes a roughing process S1, a remaining cutting process S2, and a finishing process S3. The remaining cutting process S2 includes a first side cutting process S21, a determination process S22, a second side cutting process S23, and a final second side cutting process S24. The finishing process S3 includes a middle side roughing process S31, a middle side finishing process S32, a bottom finishing process S33, a side finishing process S34, a bottom finishing process S35, and a final finishing process S36.

[0027] FIG. 4 is a flowchart of a mold processing method according to Conventional Example 1 (contour machining). As shown in FIG. 4, the mold processing method of Conventional Example 1 includes a roughing process S1, a contour machining process T for remaining cutting, and a finishing process S3. The processing method of Conventional Example 1 differs from this embodiment only in the remaining cutting process S2 and the contour machining process T.

[0028] In the roughing process S1, using a roughing cutting tool 11, a forming recess 101 is dug into the metal material W. FIG. 5 is a plan view of the metal material W with the forming recess 101 dug in the roughing process S1 as viewed from above. In the roughing process S1, for example, a large-diameter end mill 111 with a tool diameter D1 = φ32 mm is used. The large-diameter end mill 111 may be either a radius end mill or a square end mill. The large-diameter end mill 111 may be either a solid type or a throw-away type. As the cutting tool 11 used for roughing, any rotary cutting tool that can be used for roughing the mold may be used other than those listed above.

[0029] In rough machining using the large-diameter end mill 111, as shown in FIG. 5, a remaining stock 101d having a size corresponding to the tool diameter of the large-diameter end mill 111 is formed at the corner 101c of the formed recess 101. The remaining stock 101d is the excess material portion of the difference between the designed shape 102c after the final finish and the shape of the corner 101c immediately after rough machining. In the case of this embodiment, the tool diameter of the solid end mill used in the final finishing step S36 is φ6 mm, and the remaining stock 101d is substantially triangular in shape when viewed from above.

[0030] In the remaining stock cutting step S2, by repeatedly executing the first side cutting step S21 and the second side cutting step S23, the remaining stock 101d at the corner 101c is cut and reduced. Hereinafter, the remaining stock cutting step S2 will be described with reference to FIGS. 6 to 10.

[0031] FIG. 6 is a partial perspective view of the metal material W showing the first side cutting step S21. FIG. 7 is a partial cross-sectional view of the metal material W showing the first side cutting step S21. FIG. 8 is a partial perspective view of the metal material W showing the second side cutting step S23. FIG. 9 is a partial cross-sectional view of the metal material W showing the second side cutting step S23. FIG. 10 is a partial cross-sectional view of the metal material W showing the remaining stock cutting step S2.

[0032] In the remaining stock cutting step S2, a solid end mill having a tool diameter of 1 / 3 or less, preferably 1 / 4 or less, and more preferably 1 / 5 or less with respect to the cutting tool for rough machining is used. In the case of this embodiment, since the large-diameter end mill 111 for rough machining is φ32 mm, the solid end mill used in the remaining stock cutting step S2 is a solid end mill with a tool diameter D2 ≦ φ10.6 mm. In the remaining stock cutting step S2 of this embodiment, the ball end mill 112 with a tool diameter of φ6 mm shown in FIGS. 5 and 7 is used as the solid end mill for cutting the remaining stock at the corner.

[0033] The lower limit value of the tool diameter D2 of the solid end mill used in the roughing cutting process S2 is not particularly limited, but it is preferable to set the lower limit value as the tool diameter of the end mill used in the final finishing process S36. As the solid end mill used in the roughing cutting process S2, a radius end mill can also be used. The case of executing the roughing cutting process S2 using a radius end mill will be described later.

[0034] In the roughing cutting process S2, the first side cutting process S21 and the second side cutting process S23 are repeated until the tool tip reaches the bottom surface 101a, that is, the set machining depth H. At this time, depending on the set machining depth H and the first cutting amount n1, the last first cutting amount n1 may be different from the previous first cutting amounts n1. For example, when the set machining depth H is 50 mm and the first cutting amount n1 is 6 mm, in the first side cutting process S21 from the first time to the eighth time, the first cutting amount n1 is 6 mm, but the last (ninth) cutting amount is 2 mm. Alternatively, there may be a case where cutting is performed by equal division by automatic calculation in CAM. At this time, when the first cutting amount n1 is set to 6 mm, actually, the CAM tool automatically calculates so that the first cutting amount n1 is an appropriate cutting amount within 6 mm, but even in that case, the first cutting amount n1 in the last first side cutting process S21 may be different from the previous first cutting amounts n1. In the first side cutting process S21, as shown in FIGS. 5 to 7, the remaining rough part 101d of the corner 101c is cut by side cutting using the outer peripheral edge of the ball end mill 112. The axial cutting amount (ap) in the first side cutting process S21 is equal to the ball diameter of the ball end mill 112. That is, the first cutting amount n1 in the present embodiment is 6 mm.

[0035] In the first side cutting process S21, as shown in FIG. 6, the ball end mill 112 moves in an arc shape along the side surface 101b and the corner portion 101c while gradually approaching the corner portion 101c without exceeding the pick feed Pmax set toward the corner portion 101c. At this time, the pick feed P gradually decreases as it approaches the corner portion 101c such that Pmax≧P1≧P2≧P3···. Further, the remaining cut 101d of the corner portion 101c shown in FIG. 5 is side cut by the ball blade and the outer peripheral blade of the ball end mill 112.

[0036] As shown in FIG. 7, by the first side cutting process S21, in the machining depth range of the first cutting amount n1, the remaining cut 101d is generally cut. The ball end mill 112 cuts to the designed cutting position 103c shown by the imaginary line in FIG. 7. Usually, since the side surface 101b and the corner portion 101c of the formed recess 101 are inclined surfaces inclined with respect to the mold extraction direction, in the first side cutting process S21, at the position of the machined surface 101f cut by the outer peripheral blade of the ball end mill 112, a remaining cut protrusion 101e protruding from the designed cutting position 103c toward the inside of the formed recess 101 remains.

[0037] Next, as shown in FIGS. 8 and 9, in the second side cutting process S23, the remaining cut protrusion 101e (FIG. 7) generated in the first side cutting process S21 is cut by the finishing cut of the ball end mill 112. Specifically, in the second side cutting process S23, while moving the ball end mill 112 in the depth direction by the second cutting amount n2 in the direction opposite to the machining depth direction, the surface machined in the first side cutting process S21 is cut by the outer peripheral blade of the ball end mill 112. At this time, the axial cutting amount of the ball end mill 112 is set to the second cutting amount n2 which is smaller than the first cutting amount n1.

[0038] In this embodiment, the second cutting amount n2 is set to 1.5 mm. Since the first cutting amount n1 is 6 mm, in the second side cutting process, cutting is performed in three passes at 1.5 mm in the direction opposite to the depth direction. In the second side cutting process S23, the locus of the ball end mill 112 when viewing the metal material W from above is the locus shown in FIG. 8.

[0039] In this embodiment, the radial cutting amount (ae) in the second side cutting process is equal to the radial cutting amount (ae) in the first side cutting process S21. The radial cutting amount (ae) may be different between the first side cutting process S21 and the second side cutting process S23. As shown in FIG. 8, due to the cutting in the second side cutting process S23, a part of the surface processed in the first side cutting process S21 is cut in the radial direction. Thereby, the remaining cutting protrusion 101e is cut and becomes small enough not to be an obstacle in the next process.

[0040] In this embodiment, three-pass cutting is performed in the second side cutting process S23, but the second cutting amount n2 can be changed. For example, in the second side cutting process S23, the second cutting amount n2 may be set to 3 mm and one-pass cutting may be performed. Alternatively, in the second side cutting process S23, the second cutting amount n2 may be set to 2 mm and two-pass cutting may be performed.

[0041] Note that at the deepest part of the forming recess 101, the first cutting amount n1 in the first side cutting process S21 may be less than 6 mm. For example, when the first cutting amount n1 at the deepest part is 3 mm, in the second side cutting process S23, only one-pass cutting is performed under the condition that the second cutting amount n2 is 1.5 mm. Note that the second cutting amount n2 is always constant.

[0042] In the first side cutting process S21, it is determined whether the tip of the ball end mill 112 has reached the designed cutting position of the bottom surface 101a. Note that the bottom surface of the corner portion 101c is the remaining uncut portion, and in terms of shape, it is the bottom surface or the set machining depth at the applicable location. The tool tip at the time of determination refers to the portion closest to the bottom surface of the corner portion 101c or the set machining depth during cutting.

[0043] If the tip position of the ball end mill 112 in the first side cutting process S21 has not reached the bottom surface of the formed recess 101 (S22-NO), as shown in FIG. 3, the process returns to the first side cutting process S21, and the next-stage cutting process is continued. In the next-stage first side cutting process S21, the ball end mill 112 cuts into the position 112N shown by the two-dot chain line in FIG. 9, and cuts the remaining uncut portion 101d of the lower corner portion 101c by the cutting amount (n1) of the first cutting (6 mm). In the subsequent second side cutting process S23, the remaining uncut protrusion 101e in FIG. 9 generated in the first side cutting process S21 is cut.

[0044] Thus, in the mold processing method of this embodiment, as shown in FIG. 10, the first side cutting process S21 that cuts into the remaining uncut portion 101d downward and the second side cutting process S23 that cuts the surface processed in the first side cutting process S21 upward are repeated until the tip of the ball end mill 112 reaches the designed cutting position of the bottom surface 101a. As a result, the remaining uncut portion 101d of the corner portion 101c is cut from the upper end to the lower end of the formed recess 101.

[0045] Note that when the tip of the ball end mill 112 reaches the bottom surface 101a, that is, when the tool tip reaches the set machining depth H (S22-YES), after performing the last second side cutting process S24, the remaining uncut cutting process S2 ends, and the process proceeds to the finishing process S3.

[0046] As shown in Fig. 3, the finishing process S3 includes a rough side surface machining process S31, a semi-finishing side surface machining process S32, a semi-finishing bottom surface machining process S33, a side surface finishing process S34, a bottom surface finishing process S35, and a final finishing process S36. The finishing process S3 of this embodiment is an example of finishing in die machining, and the specific configuration of the process can be changed as appropriate. For example, the rough side surface machining process S31 may be omitted. Also, the semi-finishing side surface machining process S32 and the side surface finishing process S34 may be executed as one side surface finishing process. The semi-finishing bottom surface machining process S33 and the bottom surface finishing process S34 may be executed as one bottom surface finishing process.

[0047] In the case of this embodiment, in the rough side surface machining process S31, the semi-finishing side surface machining process S32, and the side surface finishing process S34, an end mill with a tool diameter of φ10 mm is used. In the semi-finishing bottom surface machining process S33 and the bottom surface finishing process S35, an end mill with a tool diameter of φ16 mm is used. In the final finishing process S36, an end mill with a tool diameter of φ6 mm is used.

[0048] With the completion of the finishing process S3, a series of processes in the die machining method of this embodiment are completed. Through the above processes, a die having a forming recess 101 is obtained.

[0049] The following Table 1 shows the results of measuring the surface properties of the corner 101c after machining up to the final finishing process in this embodiment and the surface properties of the corner 101c after machining in Conventional Example 1 (contour machining). Fig. 11 shows the measurement positions of the surface properties. Note that a non-contact three-dimensional measuring instrument (ATOS) was used for the measurement, and the uneven shape of the corner was measured. The obtained measurement data was compared with the CAD model used at the time of creating the machining program, and the difference from the target value, that is, the remaining amount of cutting, was calculated. Also, in this embodiment, after the rough machining step S1, a remaining cutting step S2 was performed, and finally a finishing step S3 was performed. On the other hand, in the conventional example 1 (contour machining), after the rough machining step S1, a contour machining step T was performed, and finally the finishing step S3 was performed. At this time, the cutting conditions of the rough machining step S1 and the finishing step S3 in this embodiment and the conventional example 1 (contour machining) are all the same, and only the remaining cutting step S2 and the contour machining step T are different. Next, the cutting conditions of the remaining cutting step S2 of this embodiment shown in Table 1 and the contour machining step T of the conventional example 1 (contour machining) are shown. In the remaining cutting step S2 in this embodiment, using a solid ball end mill with a tool diameter of φ6 mm, the rotational speed is 4775 min -1 , the cutting speed is 90 m / min, the feed rate is 1432 mm / min, the feed per tooth is 0.1 mm / tooth, the first cutting depth (n1) in the first side cutting is 6 mm, and the second cutting depth (n2) in the second side cutting is 1.5 mm. After that, the finishing step S3 was performed. On the other hand, in the contour machining step T of the conventional example 1 (contour machining), using a tip-exchangeable ball end mill with a tool diameter of φ16 mm, the rotational speed is 2000 min -1 , the cutting speed is 100 m / min, the feed rate is 480 mm / min, the feed per tooth is 0.12 mm / tooth, the cutting depth (ap) is 0.8 mm, and the cutting width (ae) is 1.4 mm. Contour machining was performed from the top to the bottom of the corner. After that, the tool was exchanged for a tip-exchangeable ball end mill with a tool diameter of φ12 mm, and the rotational speed was 1855 min -1 , the cutting speed is 70 m / min, the feed rate is 265 mm / min, the feed per tooth is 0.07 mm / tooth, the cutting depth (ap) is 0.3 mm, and the cutting depth (ae) or the remaining amount of the previous process was used to perform contour machining from the top to the bottom of the corner again.

[0050]

Table 1

[0051] As shown in Table 1, in this embodiment, the machining accuracy difference with respect to the target value became smaller than that of Conventional Example 1 (contour machining) at all machining sites. This is because, by repeatedly advancing the cutting toward the deepest part while using a solid end mill with a sufficiently small diameter (specifically, a solid end mill with a tool diameter of 1 / 3 or less) with respect to the tool used in the rough machining step S1 in the first side cutting step S21 and the second side cutting step S23, as described with reference to FIG. 9, the remaining cutting protrusion 101e is cut at any time in the second side cutting step S23.

[0052] Also, as a conventional example 2, when the corner part is cut down from the top to the bottom at once under the conditions of the first side cutting step S21 of the present invention and then the corner part is cut up from the bottom to the top at once under the conditions of the first side cutting step S21 of the present invention, that is, when the first side cutting step S21 and the second side cutting step S23 are performed individually, it is often impossible to create a machining program. This is because, as shown in FIG. 12, there is a risk that the tool will collide with the step (remaining cutting protrusion 101e) generated by the previous machining. Although there is a method of reducing the step so that the tool does not collide with the step generated by the previous machining, it is necessary to reduce the cutting depth when reducing the step. If the cutting depth is reduced, the machining time will become longer. Therefore, Conventional Example 2 is not suitable for the object of the present invention, which is to cope with the remaining cutting at the corner part without making the machining time longer than necessary and to improve the machining accuracy.

[0053] According to the method for machining a mold of the present embodiment described above, by cutting the remaining cutting 101d of the corner part 101c by the remaining cutting step S2, compared with the conventional machining method, the machining time and the process can be shortened to an equal or shorter length, and a highly accurate machined surface can be obtained on the final finishing surface.

[0054] In the conventional remaining cutting process, after performing contour machining from the upper part to the lower part of the corner using an end mill with a tool diameter of φ16 mm, the remaining cutting 101d was gradually cut by performing contour machining again from the upper part to the lower part of the corner using an end mill with a tool diameter of φ12 mm. In contrast, in the remaining cutting process S2 of the present embodiment, the remaining cutting 101d is cut using a ball end mill 112 with a tool diameter (φ6 mm) that is 1 / 3 or less of the tool diameter (φ32 mm) of the large-diameter end mill 111 used in the rough machining process S1.

[0055] In the present embodiment, by using a ball end mill 112 with a small tool diameter that allows the use of the outer peripheral edge, the remaining cutting generated by a single machining becomes smaller than when using an end mill with a tool diameter such as φ16 mm. Also, by reducing the radial cutting amount (ae) to about 8 to 10% of the tool diameter D, the axial cutting amount can be increased to about the same as the ball diameter (6 mm) of the ball end mill 112. Since the axial cutting amount in the conventional contour machining is 0.5 mm or less, the axial cutting amount in the present embodiment is more than 10 times larger.

[0056] Also, in the second side cutting process S23 for cutting the remaining cutting protrusion 101e generated in the first side cutting process S21, by using the same ball end mill 112 as in the first side cutting process S21 and reducing the radial cutting amount (ae), the axial cutting amount can be set to about 1.5 mm to 3 mm, for example. The remaining cutting protrusion 101e can be cut in a short machining time.

[0057] As described above, according to the present embodiment, the machining time in the first side cutting process S21 and the second side cutting process S23 can be significantly reduced compared to the conventional contour machining. Furthermore, since a solid end mill with a common tool diameter is used in both the first side cutting process S21 and the second side cutting process S23, tool replacement between processes is not required. As a result, the process of cutting the remaining cutting 101d of the corner 101c can be shortened compared to the conventional process.

[0058] In the conventional machining of the remaining cutting at the corner by contour machining, after cutting the remaining material at the corner with an end mill having a tool diameter of φ12 mm, side finishing is performed using an end mill having a tool diameter of φ10 mm, and then, after final finishing using an end mill having a tool diameter of φ6 mm, the corner of the formed recess is finished. That is, in the final finishing step, final finishing is performed using an end mill having a tool diameter of φ6 mm on the surface machined with an end mill having a tool diameter of φ10 mm.

[0059] On the other hand, in the present embodiment, the surface of the corner 101c machined in the final finishing step S36 is the surface machined using the ball end mill 112 having a tool diameter of φ6 mm in the second side cutting step S23. That is, in the machining method of the present embodiment, final finishing is performed on the surface with less remaining cutting compared to the conventional method. Therefore, the convex portion that cannot be completely cut in the final finishing step S36, that is, the remaining cutting portion is reduced, and a smoother and higher-precision machined surface can be obtained.

[0060] In the above embodiment, the first cutting amount n1 in the first side cutting step S21 is set to a length that coincides with the ball diameter of the ball end mill 112, but the length of the first cutting amount n1 may be changed. The first cutting amount n1 is preferably set to a length that is 0.8 times or more and 1.5 times or less the ball diameter of the ball end mill 112, and more preferably 1.2 times or less the length. By setting such a range, the remaining cutting 101d of the corner 101c can be efficiently cut in the same manner as in the above embodiment.

[0061] In the above embodiment, the second cutting amount n2 in the second side cutting step S23 is set to 1.5 mm and is 0.25 times the ball radius of the ball end mill 112. The second cutting amount n2 can be arbitrarily set as long as it is smaller than the first cutting amount n1. The second cutting amount n2 may be set to 0.2 times or more and 1.2 times or less the ball radius of the ball end mill 112. The second cutting amount may be 1 / 5, 1 / 4, 1 / 3, or 1 / 2 of the first cutting amount n1.

[0062] In the above-described embodiment, the case of cutting the remaining material 101d using the ball end mill 112 has been described. However, even when a radius end mill is used, high-speed cutting of the remaining material 101d is possible by the same process.

[0063] When using a radius end mill in the remaining material cutting step S2, the first cutting depth n1 in the first side cutting step S21 is, for example, set to 0.8 times the blade length of the radius end mill. The first cutting depth n1 may be set to a length of 0.7 times or more and 0.9 times or less the blade length of the radius end mill. According to this configuration, similar to the case of using the ball end mill 112, the remaining material 101d at the corner 101c can be efficiently cut.

[0064] When using a radius end mill in the remaining material cutting step S2, the second cutting depth n2 in the second side cutting step S23 is, for example, set to 1.0 times the corner R of the radius end mill. The second cutting depth n2 may be set to 0.8 times or more and 1.5 times or less, or 0.8 times or more and 1.2 times or less the corner R of the radius end mill. According to this configuration, it is easy to reduce the unevenness of the surface machined in the second side cutting step S23.

[0065] For example, when the tool diameter of the radius end mill is φ10 mm, the axial length of the outer peripheral edge is 10 mm, and the corner R is 2 mm, the first cutting depth n1 is preferably in the range of 7 mm or more and 9 mm or less, and the second cutting depth n2 is preferably in the range of 1.6 mm or more and 2.4 mm or less.

[0066] In the above embodiment, the tool diameter (φ6 mm) of the ball end mill 112 is configured to match the tool diameter (φ6 mm) of the cutting tool for the final finishing of the corner portion 101c, but it is not limited thereto. The tool diameter of the ball end mill 112 can be changed within a range of 1 times or more and 1.6 times or less the tool diameter of the cutting tool for the final finishing. The same applies when using a radius end mill instead of the ball end mill 112. By setting the tool diameter of the solid end mill used in the remaining cutting process S2 within the above range, it is possible to reduce the remaining cutting of the corner portion 101c before the final finishing process S36 and improve the quality of the final finishing.

[0067] In the above embodiment, the inclination angle of the corner portion 101c of the formed recess 101 is preferably 30° or more and less than 90°. When the inclination angle is less than 30°, in order to obtain a smooth machined surface, the first cutting amount n1 has to be reduced, resulting in an increase in machining time. Also, the upper limit value of the inclination angle depends on the tool holder 14 used. For example, if the tool holder 14 is of a type with a taper angle and the taper angle is 3°, the upper limit of the inclination angle of the corner portion is 86°. Also in this case, if the inclination angle exceeds 86°, it is necessary to use a solid end mill with a large protruding length to machine a deep position of the corner portion 101c, making it difficult to stabilize the side cutting using the outer peripheral blade.

[0068] The mold processing method described above can also be configured as a mold processing program executable by the control unit 16 of the mold processing apparatus 10. That is, a program can be configured to execute the mold processing method of the above embodiment as a mold processing program that causes a computer constituting the control unit 16 to set the movement path of the cutting tool 11 in the metal material W based on the shape data of the formed recess 101. By executing the above mold processing program, a formed recess can be formed at high speed and with high quality as compared with the prior art.

[0069] The above-described mold processing program may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the "computer system" includes hardware such as an OS and peripheral devices. Also, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, etc., and a storage device such as a hard disk built into a computer system. Furthermore, the "computer-readable recording medium" may be a medium that dynamically holds a program for a short time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and may also include a medium that holds a program for a certain period of time, like a volatile memory inside a computer system that serves as a server or a client. Also, the above program may be configured to implement a part of the aforementioned functions, or may further be configured to be able to implement the aforementioned functions in combination with a program already recorded in the computer system, or may be configured to be implemented using a programmable logic device such as an FPGA (Field Programmable Gate Array).

Explanation of Signs

[0070] 10…Mold processing device, 11…Cutting tool, 12…Spindle, 14…Tool holder, 15…Metal material holder, 101…Forming recess, 101b…Side surface, 101c…Corner, 101d…Remaining cut, 112…Ball end mill, n1…First cutting depth, n2…Second cutting depth, S1…Rough machining process, S2…Remaining cut cutting process, S3…Processing process, S21…First side surface cutting process, S23…Second side surface cutting process, W…Metal material

Claims

1. A method for machining a mold, comprising: a rough machining step of cutting a metal material to roughly machine a formed recess; after the rough machining, a remaining cutting step of cutting a remaining portion of a corner formed between side surfaces of the formed recess; The cutting tool used in the remaining cutting step is a solid end mill having a tool diameter of 1 / 3 or less of that of the cutting tool for rough machining. The remaining cutting step includes: a first side cutting step of cutting the remaining portion of the corner by side cutting in the axial direction with at least one of an outer peripheral edge and an arc edge of the solid end mill with a first cutting depth (n1); a second side cutting step of cutting the surface machined in the first side cutting step with the solid end mill while moving the solid end mill in a direction opposite to the machining depth direction with a second cutting depth (n2) smaller than the first cutting depth (n1); The steps are repeatedly executed over the depth direction of the corner. A method for machining a mold.

2. The solid end mill is a ball end mill, and the first cutting depth in the first side cutting step is a length of 0.8 times or more and 1.5 times or less of the ball diameter of the solid end mill. The method for machining a mold according to Claim 1.

3. The solid end mill is a ball end mill, and the second cutting depth in the second side cutting step is 0.2 times or more and 1.2 times or less of the ball radius of the solid end mill. The method for machining a mold according to Claim 1 or 2.

4. The solid end mill is a radius end mill, and the first cutting depth in the first side cutting step is a length of 0.5 times or more and 0.9 times or less of the edge length of the solid end mill. The method for machining a mold according to Claim 1.

5. The solid end mill is a radius end mill, and the first cutting depth in the first side cutting step is a length of 0.8 times or more and 1.5 times or less of the tool diameter of the solid end mill. The method for machining a mold according to Claim 1 or 4.

6. The solid end mill is a radius end mill, and the second cutting depth in the second side cutting step is 0.8 times or more and 1.5 times or less of the corner R of the solid end mill. The method for machining a mold according to Claim 1 or 4 or 5.

7. ​ ​ The tool diameter of the solid end mill is 1 time or more and 1.6 times or less the tool diameter of the cutting tool for final finishing of the corner portion, and the mold processing method according to any one of claims 1 to 6.

8. The inclination angle of the corner of the formed recess is 30° or more and less than 90°, and the mold processing method according to any one of claims 1 to 7.

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