JP7705028B2 - Mold processing method - Google Patents

Description

The present invention relates to a method for processing a mold.

Methods for machining the remaining corners of dies that are created during rough machining have been studied. One method for cutting the remaining corners involves performing contour machining multiple times while gradually reducing the tool diameter, gradually reducing the size of the remaining corners without reducing machining efficiency too much, and finally reducing the remaining corners to a size that does not affect the next process.

JP 2002-14711 A

For example, Patent Document 1 discloses a flow chart in which contour machining is performed on the remaining corner parts, and the process is repeated until the remaining parts reach the desired size.

However, in the processing method disclosed in Patent Document 1, contour machining is performed multiple times with multiple tools on the uncut corners. Therefore, in addition to the time required for cutting, the time required for tool replacement is also required, which makes the processing time for the uncut corners extremely long.

In view of the above problems, the present invention aims to provide a processing method that can shorten processing time and processes by using only one type of cutting tool in the processing process that reduces the amount of uncut corners.

According to one aspect of the present invention, there is provided a method for machining a mold, comprising a rough machining step of roughly machining a molded recess by cutting a metal material, and a remaining cutting step of cutting the remaining corners of the molded 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, and more preferably 1/5 or less, of the cutting tool used for rough machining. The uncut portion cutting process includes a first side cutting process in which the uncut portion of the corner is cut by cutting the side surface with a first cutting depth (n1) in the axial direction using at least one of the peripheral blade and the arc blade of the solid end mill, and a second side cutting process in which the surface machined in the first side cutting process is cut by the solid end mill while moving the solid end mill in the direction opposite to the machining depth direction under the condition that the cutting depth in the axial direction is a second cutting depth (n2) smaller than the first cutting depth (n1).

According to the above-mentioned configuration, the uncut portion of the corner can be sufficiently reduced by simply performing the first side cutting process and the second side cutting process alternately from top to bottom once. This is because the tool diameter of the cutting tool used in the first side cutting process and the second side cutting process is very small, less than one-third the diameter of the cutting tool used in the rough machining process, so the tool can reach the corner in one process. In addition, because the second cutting depth is smaller than the first cutting depth, the uncut portion generated in the first side cutting process is further reduced by the second side cutting process, and can be reduced in one process to a size that does not adversely affect the next process.

Furthermore, normally, if the tool diameter of the cutting tool is small, the amount of cut also becomes small, resulting in a long machining time. However, the present invention can achieve its effect by using a large cut in the first side cutting process and side cutting the remaining part of the first process in the second side cutting process. Therefore, compared to conventional contour machining, in which machining is performed multiple times while gradually reducing the tool diameter, the remaining cutting area can be reduced to the desired size in the same or less machining time. Furthermore, since tool replacement is not required, there is no need to possess multiple tools, and the setup and time required for tool replacement is also unnecessary.

The solid end mill may be a ball end mill, and the first cutting depth in the first side cutting process may be a length that is 0.8 to 1.5 times the ball diameter of the solid end mill.

The solid end mill may be a ball end mill, and the second cutting depth in the second side cutting process may be 0.2 to 1.2 times the ball radius of the solid end mill.

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

The solid end mill may be a radius end mill, and the first cutting depth in the first side cutting process may be 0.8 to 1.5 times the tool diameter of the solid end mill.

The solid end mill may be a radius end mill, and the second cutting depth in the second side cutting process may be 0.8 to 1.5 times the corner R of the solid end mill.

The tool diameter of the solid end mill may be 1 to 1.6 times the tool diameter of the cutting tool used for final finishing of the corners.

The method may be such that the inclination angle of the corners of the molded recess is 30° or more and less than 90°.

In the present invention, the peripheral cutting blade is mainly used in the first side cutting process to reduce the remaining cutting area at the corners. Therefore, if the inclination angle of the corners is less than 30°, the peripheral cutting blade cannot be used effectively and the effects of the present invention are not fully realized. In addition, the cutting tool is attached to the spindle of the machine tool via a tool holder. There are tool holders with a tapered angle and slim types that are somewhat slender, but the upper limit of the inclination angle of the corners is always less than 90° because it is necessary to take into account the shape and protruding length of the tool holder.

According to one aspect of the present invention, a method for machining a mold is provided that can reduce the machining time for uncut corners.

FIG. 1 is a schematic diagram of a metal material W placed in a die machining device 10. FIG. 2 is a partial perspective view showing an example of a mold. FIG. 3 is a flowchart of the die machining method according to this embodiment. FIG. 4 is a flow chart of a die machining method in the conventional example 1 (contour machining). FIG. 5 is a plan view of the metal material W into which the forming recess is carved, as viewed from above. FIG. 6 is a partial top view of the metal material W showing the path of the end mill in the first side surface cutting step S21. FIG. 7 is a partial cross-sectional view of the metal material W showing the first side surface cutting step S21. FIG. 8 is a partial top view of the metal material W showing the trajectory of the end mill in the second side surface cutting step S23. FIG. 9 is a partial cross-sectional view of the metal material W showing the second side surface cutting step S23. FIG. 10 is a partial cross-sectional view of the metal material W showing the uncut cutting step S2. FIG. 11 is a diagram showing the positions at which the surface properties of the inner surface of the recessed portion are measured after the remaining cutting is completed. FIG. 12 is a partial cross-sectional view showing the uncut cutting step of Conventional Example 2.

Fig. 1 is a schematic diagram showing a metal material W placed in a die processing device 10. Fig. 2 is a partial perspective view showing an example of a die.
The mold machining apparatus 10 of this 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.

The cutting tool 11 is an appropriate type of cutting tool for each process in the mold machining method. In the machining method of this embodiment described below, a solid end mill having a cutting edge at the tip of the cutting tool is used in the first side cutting process and the second side cutting process. The solid end mill used in the machining method of this embodiment is a radius end mill, a square end mill, or a ball end mill. Furthermore, the cutting tools used in cutting processes other than the first side cutting process and the second side cutting process are not limited to solid end mills, and are determined by the machining shape and machining conditions.

The cutting tool 11 is held by the spindle 12 via a tool holder 14. Furthermore, the spindle 12 is equipped with a drive mechanism that rotates 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 can move the cutting tool 11 in three axial directions: the X-axis, the Y-axis, and the Z-axis. In this embodiment, the movement mechanism of the spindle only needs to have the aforementioned three axes, and the movement mechanism may also have a function of three or more axes, such as tilting the spindle 12 itself.

The stage 13 supports the metal material W from below via a metal material holder 15. The metal material holder 15 is equipped with a fixing mechanism for fixing the metal material W, and a posture control mechanism for adjusting the posture of the metal material W. The fixing mechanism and posture control mechanism of the stage 13 are each provided as necessary.

The control unit 16 provides overall control of the mold machining device 10. The control unit 16 is a computer capable of executing a mold machining 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.

The control unit 16 controls the spindle 12 via the tool control unit 17 to rotate the cutting tool 11 and move the cutting tool 11 in the X-axis, Y-axis and Z-axis directions. The control unit 16 controls the fixing mechanism and attitude control mechanism of the metal material holder 15 via the stage control unit 18 to hold the metal material W in a predetermined attitude.
The die machining device 10 performs 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 the die machining device 10 is used to form a molding recess 101 that opens upward as shown in FIG.

FIG. 3 is a flowchart of the die machining method according to this embodiment.
As shown in FIG. 3, the die machining method of this embodiment includes a rough machining step S1, a remaining cutting step S2, and a finish machining step S3.
The remaining cutting step S2 includes a first side surface cutting step S21, a determination step S22, a second side surface cutting step S23, and a final second side surface cutting step S24.
The finishing process S3 includes a side surface rough finishing process S31, a side surface semi-finishing process S32, a bottom surface semi-finishing process S33, a side surface finishing process S34, a bottom surface finishing process S35, and a final finishing process S36.

FIG. 4 is a flow chart of a die machining method according to the conventional example 1 (contour machining).
The machining method of the mold of the conventional example 1 includes a rough machining step S1, a contour machining step T for cutting the remaining cut parts, and a finish machining step S3, as shown in Fig. 4. The machining method of the conventional example 1 differs from this embodiment only in the remaining cut cutting step S2 and the contour machining step T.

In the rough machining step S1, a forming recess 101 is dug into the metal material W using a cutting tool 11 for rough machining.
5 is a plan view of the metal material W in which the forming recess 101 is carved in the rough machining step S1, as viewed from above. In the rough machining step S1, a large diameter end mill 111 having a tool diameter D1 of φ32 mm, for example, 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. The cutting tool 11 used for rough machining may be any cutting tool other than those listed above, so long as it is a rotary cutting tool that can be used for rough machining of a mold.

In rough machining using the large diameter end mill 111, as shown in FIG. 5, a cutting residue 101d of a size corresponding to the tool diameter of the large diameter end mill 111 is formed at the corner 101c of the forming recess 101. The cutting residue 101d is the difference between the design shape 102c after final finishing and the shape of the corner 101c immediately after rough machining. In this embodiment, the tool diameter of the solid end mill used in the final finishing process S36 is φ6 mm, and the cutting residue 101d is roughly triangular when viewed from above.

In the remaining cutting step S2, the first side cutting step S21 and the second side cutting step S23 are repeatedly performed to cut and reduce the remaining cutting 101d in the corner 101c. The remaining cutting step S2 will be described below with reference to Figures 6 to 10.

Figure 6 is a partial perspective view of the metal material W showing the first side cutting process S21. Figure 7 is a partial cross-sectional view of the metal material W showing the first side cutting process S21. Figure 8 is a partial perspective view of the metal material W showing the second side cutting process S23. Figure 9 is a partial cross-sectional view of the metal material W showing the second side cutting process S23. Figure 10 is a partial cross-sectional view of the metal material W showing the remaining cutting process S2.

In the remaining cutting step S2, a solid end mill is used whose tool diameter is 1/3 or less, preferably 1/4 or less, and more preferably 1/5 or less than that of the rough cutting tool. In the present embodiment, since the large diameter end mill 111 for rough cutting is φ32 mm, the solid end mill used in the remaining cutting step S2 is a solid end mill whose tool diameter D2≦φ10.6 mm. In the remaining cutting step S2 of this embodiment, a ball end mill 112 with a tool diameter of φ6 mm shown in FIG. 5 and FIG. 7 is used as the solid end mill for cutting the remaining corners.

The lower limit of the tool diameter D2 of the solid end mill used in the remaining cutting step S2 is not particularly limited, but it is preferable to set the tool diameter of the end mill used in the final finishing step S36 as the lower limit. A radius end mill can also be used as the solid end mill used in the remaining cutting step S2. The case where the remaining cutting step S2 is performed using a radius end mill will be described later.

In the remaining cutting step S2, the first side surface cutting step S21 and the second side surface cutting step S23 are repeated until the tip of the tool 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 depth n1, the final first cutting depth n1 may be different from the previous first cutting depth n1. For example, when the set machining depth H is 50 mm and the first cutting depth n1 is 6 mm, the first side surface cutting step S21 has a first cutting depth n1 of 6 mm from the first to eighth times, but the final (ninth) cutting depth is 2 mm. Alternatively, the cutting process may be performed in equal divisions automatically calculated by CAM. In this case, if the first cutting depth n1 is set to 6 mm, the CAM tool will automatically calculate so that the first cutting depth n1 is actually an appropriate cutting depth within 6 mm. However, even in this case, the first cutting depth n1 of the final first side cutting process S21 may differ from the previous first cutting depth n1.
5 to 7, in the first side surface cutting process S21, the uncut portion 101d of the corner portion 101c is cut by side surface cutting using the peripheral cutting edge of the ball end mill 112. The axial depth of cut (ap) in the first side surface cutting process S21 is equal to the ball diameter of the ball end mill 112. That is, the first depth of cut n1 in this embodiment is 6 mm.

In the first side cutting process S21, as shown in FIG. 6, the ball end mill 112 moves in an arc along the side 101b and the corner 101c gradually toward the corner 101c without exceeding the set pick feed Pmax. At this time, the pick feed P becomes gradually smaller as it approaches the corner 101c, such that Pmax≧P1≧P2≧P3.... Also, the uncut portion 101d of the corner 101c shown in FIG. 5 is cut on the side by the ball blade and peripheral blade of the ball end mill 112.

As shown in FIG. 7, the first side cutting process S21 cuts out most of the uncut portion 101d within the machining depth range of the first cutting amount n1. The ball end mill 112 cuts in up to the designed cutting position 103c shown by the imaginary line in FIG. 7. Normally, the side 101b and corner 101c of the molding recess 101 are inclined surfaces that are inclined with respect to the mold removal direction, so in the first side cutting process S21, the uncut protrusion 101e that protrudes from the designed cutting position 103c toward the inside of the molding recess 101 remains at the position of the machining surface 101f cut by the peripheral blade of the ball end mill 112.

Next, as shown in FIGS. 8 and 9, in a second side surface cutting step S23, the uncut protrusion 101e (FIG. 7) generated in the first side surface cutting step S21 is cut by cutting using a ball end mill 112.
Specifically, in the second side surface cutting step S23, the ball end mill 112 is moved in the depth direction by a second cutting depth n2 in the direction opposite to the machining depth direction, while the surface machined in the first side surface cutting step S21 is cut by the peripheral blade of the ball end mill 112. At this time, the cutting depth in the axial direction of the ball end mill 112 is set to a second cutting depth n2 smaller than the first cutting depth n1.

In this embodiment, the second cutting depth n2 is set to 1.5 mm. Since the first cutting depth n1 is 6 mm, in the second side cutting process, three passes of cutting are performed at 1.5 mm in the direction opposite to the depth direction. In the second side cutting process S23, the trajectory of the ball end mill 112 when the metal material W is viewed from above is the trajectory shown in Figure 8.

In this embodiment, the radial depth of cut (ae) in the second side cutting process is equal to the radial depth of cut (ae) in the first side cutting process S21. The radial depth of cut (ae) may differ between the first side cutting process S21 and the second side cutting process S23. As shown in FIG. 8, the cutting in the second side cutting process S23 cuts a portion of the surface machined in the first side cutting process S21 into the radial direction. This cuts the remaining protrusion 101e, making it small enough that it will not cause an obstacle in the next process.

In this embodiment, three passes of cutting are performed in the second side cutting process S23, but the second cutting depth n2 can be changed. For example, in the second side cutting process S23, the second cutting depth n2 may be set to 3 mm and one pass of cutting may be performed. Alternatively, in the second side cutting process S23, the second cutting depth n2 may be set to 2 mm and two passes of cutting may be performed.

In addition, at the deepest part of the molding recess 101, the first cut depth n1 in the first side cutting process S21 may be less than 6 mm. For example, if the first cut depth n1 at the deepest part is 3 mm, in the second side cutting process S23, cutting is performed in only one pass under the condition that the second cut depth n2 is 1.5 mm. In addition, the second cut depth n2 is always constant.

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

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

As shown in FIG. 10, in the machining method of the mold of this embodiment, a first side cutting process S21 in which the uncut portion 101d is cut downward, and a second side cutting process S23 in which the surface machined in the first side cutting process S21 is cut upward are repeated until the tip of the ball end mill 112 reaches the designed cut position of the bottom surface 101a. As a result, the uncut portion 101d of the corner portion 101c is cut from the upper end to the lower end of the molding recess 101.

When the tip of the ball end mill 112 reaches the bottom surface 101a, i.e., when the tip of the tool reaches the set machining depth H (S22-YES), the final second side cutting step S24 is performed, after which the remaining cutting step S2 ends and the process moves to the finishing step S3.

As shown in FIG. 3, the finishing process S3 includes a side surface medium rough machining process S31, a side surface medium finishing process S32, a bottom surface medium finishing 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 side surface medium rough machining process S31 may be omitted. Also, the side surface medium finishing process S32 and the side surface finishing process S34 may be performed as one side surface finishing process. The bottom surface medium finishing process S33 and the bottom surface finishing process S34 may be performed as one bottom surface finishing process.

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

Completion of the finishing process S3 completes the series of steps in the die machining method of this embodiment. Through these steps, a die having a molding recess 101 is obtained.

The results of measuring the surface quality of the corner 101c after the final finish machining in this embodiment and the surface quality of the corner 101c after machining in Conventional Example 1 (contour machining) are shown in Table 1 below. FIG. 11 shows the measurement positions of the surface quality. A non-contact three-dimensional measuring device (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 when the machining program was created, and the difference from the target value, i.e., the amount of uncut material, was calculated.
In this embodiment, after the rough machining step S1, the remaining cutting step S2 was performed, and finally the finish machining step S3 was performed. On the other hand, in the conventional example 1 (contour machining), after the rough machining step S1, the contour machining step T was performed, and finally the finish machining step S3 was performed. In this case, the cutting conditions of the rough machining step S1 and the finish machining 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, cutting conditions for the uncut cutting step S2 of this embodiment and the contour line machining step T of the conventional example 1 (contour line machining) are shown in Table 1.
In this embodiment, the remaining cutting step S2 was performed using a solid ball end mill with a tool diameter of φ6 mm, with a rotation speed of 4775 min ^-1 , a cutting speed of 90 m/min, a feed speed of 1432 mm/min, and a feed per tooth of 0.1 mm/tooth. The first cutting depth (n1) in the first side cutting process was 6 mm, and the second cutting depth (n2) in the second side cutting process was 1.5 mm. Then, the finishing process S3 was performed.
On the other hand, in the contour machining process T of Conventional Example 1 (contour machining), a replaceable-blade ball end mill with a tool diameter of φ16 mm was used to perform contour machining from the top to the bottom of the corner at a rotation speed of 2000 min ^-1 , a cutting speed of 100 m/min, a feed speed of 480 mm/min, a feed per blade of 0.12 mm/tooth, a cutting depth (ap) of 0.8 mm, and a cutting width (ae) of 1.4 mm. After that, the tool was replaced with a replaceable-blade ball end mill with a tool diameter of φ12 mm, and contour machining was performed again from the top to the bottom of the corner at a rotation speed of 1855 min ^-1 , a cutting speed of 70 m/min, a feed speed of 265 mm/min, a feed per blade of 0.07 mm/tooth, a cutting depth (ap) of 0.3 mm, and the cutting depth (ae) or the remaining amount from the previous process.

As shown in Table 1, in this embodiment, the difference in machining accuracy with respect to the target value was smaller than in Conventional Example 1 (contour machining) in all machining areas. This is because the first side cutting process S21 and the second side cutting process S23 are repeated using a solid end mill with a sufficiently small diameter (specifically, a solid end mill with a tool diameter of 1/3 or less) compared to the tool used in the rough machining process S1, while cutting to the deepest part, and the uncut protrusion 101e is cut as needed in the second side cutting process S23, as explained in FIG. 9.

In addition, in the case of conventional example 2, when the corner is cut downward from top to bottom in one go under the conditions of the first side cutting process S21 of the present invention, and then the corner is cut upward from bottom to top in one go under the conditions of the first side cutting process S21 of the present invention, that is, when the first side cutting process S21 and the second side cutting process 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 (uncut protrusion 101e) caused by the previous processing. There is a method of reducing the step so that the tool does not collide with the step caused by the previous processing, but in order to reduce the step, the cutting depth must also be reduced. If the cutting depth is reduced, the processing time will also be longer, so conventional example 2 is not suitable for the purpose of the present invention, which is to deal with the uncut corners and improve processing accuracy without unnecessarily lengthening the processing time.

According to the above-described method for machining a die according to this embodiment, by cutting the remaining cut portion 101d at the corner portion 101c in the remaining cut portion cutting process S2, it is possible to shorten the machining time and process steps by an equal or greater amount compared to conventional machining methods, and to obtain a highly accurate machined surface on the final finished surface.

In the conventional uncut cutting process, contour machining is performed from the top to the bottom of the corner using an end mill with a tool diameter of φ16 mm, and then contour machining is performed again from the top to the bottom of the corner using an end mill with a tool diameter of φ12 mm, gradually cutting the uncut portion 101d. In contrast, in the uncut cutting process S2 of this embodiment, the uncut portion 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.

In this embodiment, by using a ball end mill 112 with a small tool diameter that allows the use of a peripheral cutting edge, the amount of leftover cutting caused by one machining is smaller than when an end mill with a tool diameter of φ16 mm or the like is used. In addition, by reducing the radial depth of cut (ae) to about 8-10% of the tool diameter D, the axial depth of cut can be increased to the same extent as the ball diameter (6 mm) of the ball end mill 112. The axial depth of cut in conventional contour machining is 0.5 mm or less, so the axial depth of cut in this embodiment is more than 10 times larger.

In addition, in the second side cutting process S23, which cuts the uncut protrusion 101e generated in the first side cutting process S21, the same ball end mill 112 as in the first side cutting process S21 is used to reduce the radial cutting depth (ae), making it possible to reduce the axial cutting depth to, for example, about 1.5 mm to 3 mm. The uncut protrusion 101e can be cut in a short processing time.

As described above, according to this embodiment, the processing time in the first side cutting process S21 and the second side cutting process S23 can be significantly reduced compared to conventional contour line processing. Furthermore, since a solid end mill with a common tool diameter is used in the first side cutting process S21 and the second side cutting process S23, there is no need to change cutting tools between processes. As a result, the process of cutting the remaining portion 101d of the corner portion 101c can be shortened compared to the conventional process.

In addition, in conventional contour machining to remove the remaining corner parts, an end mill with a tool diameter of φ12 mm is used to remove the remaining corner parts, then a side surface finishing process is performed using an end mill with a tool diameter of φ10 mm, and then a final finishing process is performed using an end mill with a tool diameter of φ6 mm to finish the corner parts of the molded recess. In other words, in the final finishing process, a final finishing process is performed using an end mill with a tool diameter of φ6 mm on the surface machined with the end mill with a tool diameter of φ10 mm.

In contrast, in this embodiment, the surface of the corner portion 101c machined in the final finishing step S36 is the surface machined in the second side cutting step S23 using a ball end mill 112 with a tool diameter of φ6 mm. In other words, in the machining method of this embodiment, the final finishing is performed on a surface with less uncut areas compared to the conventional method. Therefore, there are fewer convex parts that cannot be completely cut in the final finishing step S36, i.e., less uncut areas, and a smoother, more highly accurate machined surface can be obtained.

In the above embodiment, the first cutting depth n1 in the first side cutting process S21 is set to a length that matches the ball diameter of the ball end mill 112, but the length of the first cutting depth n1 may be changed. The first cutting depth n1 is preferably set to a length that is 0.8 to 1.5 times the ball diameter of the ball end mill 112, and more preferably 1.2 times or less. By setting it in such a range, the uncut portion 101d of the corner portion 101c can be efficiently cut, as in the above embodiment.

In the above embodiment, the second cutting depth n2 in the second side cutting process S23 is 1.5 mm, which is 0.25 times the ball radius of the ball end mill 112. The second cutting depth n2 can be set arbitrarily as long as it is shorter than the first cutting depth n1. The second cutting depth n2 may be 0.2 to 1.2 times the ball radius of the ball end mill 112. The second cutting depth may be 1/5, 1/4, 1/3, or 1/2 of the first cutting depth n1.

In the above embodiment, the case where the uncut portion 101d is cut using a ball end mill 112 is described, but the uncut portion 101d can also be cut at high speed using a radius end mill by a similar process.

When a radius end mill is used in the remaining cutting step S2, the first cutting depth n1 in the first side cutting step S21 is, for example, 0.8 times the blade length of the radius end mill. The first cutting depth n1 may be 0.7 to 0.9 times the blade length of the radius end mill. With this configuration, the remaining cutting depth 101d in the corner 101c can be efficiently cut, similar to when the ball end mill 112 is used.

When a radius end mill is used in the remaining cutting process S2, the second cutting depth n2 in the second side cutting process S23 is, for example, 1.0 times the corner R of the radius end mill. The second cutting depth n2 may be 0.8 to 1.5 times, or 0.8 to 1.2 times, the corner R of the radius end mill. This configuration makes it easier to reduce unevenness in the surface machined in the second side cutting process S23.

For example, if the tool diameter of the radius end mill is φ10 mm, the axial length of the peripheral cutting edge is 10 mm, and the corner R is 2 mm, it is preferable that the first cutting depth n1 is in the range of 7 mm to 9 mm, and the second cutting depth n2 is in the range of 1.6 mm to 2.4 mm.

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 final finishing of the corner portion 101c, but this is not limited to this. The tool diameter of the ball end mill 112 can be changed within a range of 1 to 1.6 times the tool diameter of the cutting tool for final finishing. The same applies when a radius end mill is used 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, the remaining cutting of the corner portion 101c can be reduced before the final finishing process S36, and the quality of the final finish can be improved.

In the above embodiment, the inclination angle of the corner 101c of the molding recess 101 is preferably 30° or more and less than 90°. If the inclination angle is less than 30°, the first cutting depth n1 must be reduced to obtain a smooth machined surface, which increases the machining time. The upper limit of the inclination angle depends on the tool holder 14 used. For example, if the tool holder 14 is a type with a taper angle and the taper angle is 3°, the upper limit of the inclination angle of the corner is 86°. In this case, if the inclination angle exceeds 86°, a solid end mill with a large protruding length must be used to machine the deep position of the corner 101c, and side cutting using the peripheral cutting edge becomes difficult to stabilize.

The above-described die machining method can also be configured as a die machining program executable by the control unit 16 of the die machining device 10. That is, a program for executing the die machining method of the above-described embodiment can be configured as a die machining program that causes the computer constituting the control unit 16 to set a movement path of the cutting tool 11 in the metal material W based on shape data of the molding recess 101.
By executing the above-described mold machining program, a molded recess can be formed more quickly and with higher quality than in the past.

The above-mentioned mold machining program may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. The term "computer-readable recording medium" may also refer to media that dynamically hold a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, or may include media that hold a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client. The above-mentioned program may also be configured to realize a part of the above-mentioned functions, or may be configured to realize the above-mentioned functions in combination with a program already recorded in the computer system, or may be configured to be realized using a programmable logic device such as an FPGA (Field Programmable Gate Array).

10...Mold processing device, 11...Cutting tool, 12...Main shaft, 14...Tool holder, 15...Metal material holder, 101...Molding recess, 101b...Side, 101c...Corner, 101d...Remnant, 112...Ball end mill, n1...First cutting depth, n2...Second cutting depth, S1...Rough machining process, S2...Remnant cutting process, S3...Machining process, S21...First side cutting process, S23...Second side cutting process, W...Metal material

Claims (8)

A method for processing a mold, comprising the steps of:
a rough machining process for roughly machining a molded recess by cutting a metal material;
a cutting process for cutting a corner portion formed between side surfaces of the molding recess after the rough processing;
having
The cutting tool used in the residual cutting step is a solid end mill having a tool diameter that is 1/3 or less of that of the cutting tool for rough machining,
The uncut cutting step includes:
Using at least one of the peripheral blade and the circular arc blade of the solid end mill,
a first side cutting step of cutting the corner portion by cutting the side surface with a first cutting depth (n1) in the axial direction;
a second side cutting step in which the surface machined in the first side cutting step is cut by the solid end mill while moving the solid end mill in the opposite direction to the machining depth direction with a second cutting depth (n2) in the axial direction that is smaller than the first cutting depth (n1);
Repeatedly performing the above steps in the depth direction of the corner portion.
Mold processing method. The solid end mill is a ball end mill,
The first cutting amount in the first side cutting step is 0.8 to 1.5 times the ball diameter of the solid end mill.
A method for machining the mold according to claim 1. The solid end mill is a ball end mill,
The second cutting amount in the second side cutting step is 0.2 to 1.2 times the ball radius of the solid end mill.
A method for machining the mold according to claim 1 or 2. The solid end mill is a radius end mill,
The first cutting amount in the first side cutting step is 0.5 to 0.9 times the blade length of the solid end mill.
A method for machining the mold according to claim 1. The solid end mill is a radius end mill, and the first cutting depth in the first side cutting step is 0.8 to 1.5 times the tool diameter of the solid end mill.
A method for machining the mold according to claim 1 or 4. The solid end mill is a radius end mill,
The second cutting amount 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.
A method for machining a mold according to claim 1, 4 or 5. The method for machining a mold according to any one of claims 1 to 6, wherein the tool diameter of the solid end mill is 1 to 1.6 times the tool diameter of the cutting tool for final finishing of the corner portion. The method for machining a mold according to any one of claims 1 to 7, wherein the inclination angle of the corner of the molding recess is 30° or more and less than 90°.

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