JPH11114716A - Machining method of die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and quickly machine a die blank into the specified form while checking load against a milling cutter of an end mill or the like, reducing an amount of unmachining allowance, and to facilitate its finishing at the next process by installing this milling cutter where each cutting edge is installed in an outer boundary and a bottom face, and an easement means easing the load in time of machining contact of this milling cutter with the die blank, and cutting this machining contact part through a spiral milling process spirally shifting this milling cutter along the machining form. SOLUTION: This die machining method is for machining a die blank 3 by moving a milling cutter to form this die, and it is equipment with the milling cutter where each of cutting edges 6 and 7 is installed in an outer boundary and a bottom face, and an easement means easing any load against the milling cutter in time of machining contact of this milling cutter with a die blank 3, and in this constitution, this machining contact part is cut by a spiral milling process spirally shifting the milling cutter along a curve 10 of machining form. In this case, it is set in an obliquely upward point b0, and then a deep cutting part is machined with a constant infeed rate while shifting it downward aslant along a spiral path (b) as rotating, it about 600 to 1000 rpm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of cutting a mold by moving a milling tool to form a mold to cut a mold material.

[0002]

2. Description of the Related Art Conventionally, as a method of cutting a mold of the above-described example, there is a method described in Japanese Patent Application Laid-Open No. H8-2443827. That is, a mold material 91 (see FIG. 10) is provided in which the excess thickness has been removed from the blank (material) after gas welding by a punching process, and a mold surface having at least one direction contour in the mold material 91 is a curve. In order to form the mold 92, the punching process of cutting while moving the milling tool in a direction orthogonal to the cutting surface is repeatedly performed in one direction of the mold material 91.

[0003] The above-described punching process is started from a position where the mold surface 92 becomes deepest in one direction of the mold material 91 as shown by a locus line 93 in FIG. At the stroke end, the so-called oblique punching is performed, in which the slice tool is moved obliquely downward along the contour of the mold surface 92 to the position cut by the previous punching, and cut. This is a method in which the surface 92 is subjected to finish processing to form a mold.

According to the conventional die cutting method (so-called oblique punching method), there is no step-like uncut portion as seen in the conventional punching process, so that the time required for the finishing process is reduced and the efficiency of the cutting process is reduced. Although there is an advantage that it can be achieved, there are the following problems. In other words, the milling tool used for the above-mentioned punching, especially the vertical mill, is originally a blade developed for the purpose of moving vertically, so that the vertical mill has a thicker axis to counter the processing load during oblique punching. And it has increased its rigidity.

For this reason, it is unsuitable for cutting the corner portions 94 and the groove portions 95 shown in FIG. 11, and if the above-mentioned vertical mill is used for cutting the portions 94 and 95, uncut portions will be left. There was a problem.

[0006]

According to the first aspect of the present invention, there is provided a milling tool having a cutting blade provided on an outer periphery and a bottom surface, and a load applied when the milling tool is brought into contact with a mold material during cutting. Equipped with a mitigation means for relaxing, by cutting the cutting contact portion by spiral machining of the above-mentioned milling tool spirally moving along the machining shape, while suppressing the load on the milling tool such as an end mill, reliably and An object of the present invention is to provide a die cutting method capable of quickly cutting into a predetermined shape, reducing uncut portions (remaining allowance), and facilitating finishing in the next step.

According to a second aspect of the present invention, in addition to the object of the first aspect of the present invention, when machining into a mold having a curved contour, the milling tool is formed along the curved shape. By spirally moving
It is an object of the present invention to provide a method for cutting a mold, which can further reduce the uncut portion.

[0008] According to a third aspect of the present invention, in addition to the object of the first or second aspect, the milling tool is moved obliquely from above to obliquely downward to start cutting. The present invention has an object to provide a method of cutting a die, in which the load bias in the bending direction with respect to the axis of the die is small, and the resistance to the milling tool at the start of cutting can be reduced.

According to a fourth aspect of the present invention, in addition to the object of the first or second aspect of the present invention, cutting by a milling tool is started from a portion having a large curvature (a portion having a gentle curve). Another object of the present invention is to provide a die cutting method capable of reducing the load on a milling tool at the start of cutting.

According to a fifth aspect of the present invention, in addition to the object of the first or second aspect of the present invention, the moving speed of the milling tool during cutting contact is reduced as compared with other cutting times. Another object of the present invention is to provide a die cutting method capable of reducing the load on a milling tool at the start of cutting.

According to a sixth aspect of the present invention, in addition to the object of the first or second aspect of the present invention, the above-described movement of the milling tool in the spiral movement in one round is performed by obliquely upward movement. By making the trajectory along, the inclination of the movement trajectory in the diagonally upward movement becomes gentler in the diagonally downward movement, and the load bias in the bending direction with respect to the axis of the milling tool becomes as small as possible. It is an object of the present invention to provide a die cutting method capable of performing smooth cutting.

According to a seventh aspect of the present invention, in addition to the object of the first or second aspect of the present invention, the final cutting by the milling tool is performed by making one round along the machined shape, thereby leaving uncut ( It is another object of the present invention to provide a method of cutting a metal mold, which can further reduce the remaining margin and facilitate the post-processing.

[0013]

According to a first aspect of the present invention, there is provided a method of cutting a mold by moving a milling tool to form a mold and cutting a mold material.
A milling tool provided with cutting blades on the outer and bottom surfaces,
At the time of the cutting contact of the milling tool with the mold material, the cutting tool has a relief means for reducing the load on the milling tool, and the cutting contact portion is formed by a spiral process in which the milling tool is spirally moved along the processing shape. It is a cutting method of a die to be cut.

According to a second aspect of the present invention, there is provided a method of cutting a die for processing into a die shape having a curved outline, in addition to the configuration of the first aspect of the present invention. It is a cutting method of a die for spirally moving the milling tool along a shape to perform spiral processing.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, the relief means moves the milling tool from diagonally upward to diagonally downward to start cutting. It is a cutting method of a mold.

According to a fourth aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, the relief means starts the cutting of the mold by starting the cutting by the milling tool from a location having a large curvature. The method is characterized by:

According to a fifth aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, the relieving means sets the moving speed of the milling tool at the time of cutting abutment as compared with that at the time of other cutting. It is a method of cutting a mold to be reduced.

According to a sixth aspect of the present invention, in addition to the structure of the first or second aspect of the present invention, the diagonally upward movement of the milling tool in a spiral movement of the milling tool is formed into a machining shape. The method is characterized in that it is a method of cutting a die formed along a locus along the path.

According to a seventh aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, the final cutting by the milling tool is performed by cutting a die which makes one round along a machining shape. The method is characterized by:

[0020]

According to the first aspect of the present invention, when the milling tool having the cutting blades provided on the outer periphery and the bottom surface is brought into contact with the die material (particularly before and after the first touch). The relieving means described above relieves the load on the milling tool. In addition, since the above-mentioned milling tool is cut by spiral processing in which it is spirally moved while cutting along the processing shape, the contact between the cutting blade of the milling tool and the die material after the cutting contact is uniform, that is, to the milling tool Cutting can be continued in a state where the load of the end mill is reduced, cutting can be reliably and quickly performed to a predetermined shape while suppressing the load on a milling tool such as an end mill, and the uncut portion (remaining allowance) is reduced. This has the effect of facilitating finishing in the next step. Further, since the end mill having a small diameter can be used as a milling tool by the above-mentioned spiral machining, unlike a vertical mill used for a punching process, a cutting process for a corner portion or a groove-shaped portion can be easily performed.

According to the second aspect of the present invention,
In addition to the effect of the first aspect of the present invention, when machining into a mold shape having a curved contour, the above-mentioned milling tool is spirally moved along this curved shape to perform spiral machining. There is an effect that can be further reduced.

According to the third aspect of the present invention,
In addition to the effect of the first or second aspect of the present invention, the above-described relaxation means starts the cutting by moving the milling tool from obliquely upward to diagonally downward, so that the load bias in the bending direction with respect to the axis of the milling tool is reduced. This has the effect of reducing the resistance to the milling tool at the start of cutting. In contrast, when the milling tool is moved from diagonally downward to diagonally upward to start cutting, the load bias in the bending direction becomes large with respect to the axis of the milling tool. Generation of bending stress with respect to the axis can be greatly reduced.

According to the invention described in claim 4 of the present invention,
In addition to the effect of the first or second aspect of the present invention, the above-mentioned mitigation means starts the cutting by the milling tool from a location having a large curvature (a portion with a gentle curve), so that the load on the milling tool at the start of cutting is increased. There is an effect that reduction can be achieved.

According to the invention described in claim 5 of the present invention,
In addition to the effect of the first or second aspect of the present invention, the above-mentioned relaxation means reduces the moving speed of the milling tool at the time of cutting abutment as compared with other cutting times. This has the effect of reducing the load on the device.

According to the sixth aspect of the present invention,
In addition to the effect of the first or second aspect of the present invention, in the above-mentioned spiral movement of the milling tool, the diagonally upward movement is a locus along the machining shape. When performing machining, the inclination of the movement trajectory becomes gentler when moving diagonally upward than when moving diagonally downward. For this reason, the load in the bending direction urged against the axis of the milling tool is reduced as much as possible, and there is an effect that a smooth cutting process can be performed.

According to the seventh aspect of the present invention,
In addition to the effect of the first or second aspect of the present invention, since the final cutting by the milling tool makes one round along the machined shape, the uncut portion (remaining allowance) can be further reduced. This has the effect of facilitating post-processing.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The drawings show a method of cutting a mold used for molding a plastic bumper of a vehicle as an example of a method of cutting a mold.

First, as shown in FIG. 1, a mold material 1 obtained by gas-melting a steel material is provided. In the drawings, a part of the mold material 1 is shown for convenience of illustration, but this mold material 1 includes a horizontal portion 1a corresponding to a central portion extending in the vehicle width direction of the plastic bumper, and vertical portions 1b, 1b corresponding to both left and right end portions of the plastic bumper. And the entire shape is formed in a substantially U-shape. Next, the die blank 1 shown in FIG. 1 is pierced from the directions of arrows A and B in FIG. 1 using a vertical mill as a milling tool, and the die blank after the first large rough machining as shown in FIG. Cut to 2

Next, using a vertical mill as a milling tool, the die blank 2 shown in FIG. 2 is mainly punched in the direction of arrow C in FIG. 2 to form a die after completion of the second roughing as shown in FIG. The mold material 3 is cut. At this stage, most (for example, 90%) excess material is removed.

Next, the die material 3 shown in FIG. 3 is cut by the die cutting method (spiral processing along the shape) of the present invention. Note that, in the following description, the remaining portion of the portion E in FIG. 3 (a deep portion corresponding to the groove portion 95 in FIG. 11) will be described in detail, but the present invention can be applied to other portions in FIG. It goes without saying that a die cutting method can be applied.

FIGS. 4 and 5 show an end mill 4 as a milling tool used in the die cutting method of the present invention. The end mill 4 has a main blade 6 and a sub-edge 7 below a shaft 5. Each of these cutting blades 6 and 7 has its outer periphery and bottom surface set to a blade surface, and has a clearance 8 and 8 for chip discharge.
It has. That is, the main blade 6 has a bottom surface extending over the radius, and the sub blade 7 has a bottom surface extending to the outer periphery at a predetermined interval from the axis. For this reason, even in processing in which heat escape of the cutting wave is difficult,
The heat load can be reduced by the heat release.

As shown in FIG. 6, the deeply digged portion e of the portion E shown in FIG. 3 is finally finished into a mold surface 9 (mold shape) having a curved outline, leaving a very small and uniform remaining allowance a. It will be processed.

Therefore, the above-mentioned end mill 4 is shown in FIGS.
The cutting contact portion where the main blade 6 and the sub-blade 7 are in contact with each other is cut by the spiral processing for moving along the spiral locus b shown in FIG. 5, but in this case, along the shape of the curve 10 on the mold surface 9 described above. The end mill 4 is spirally moved at a fixed cutting amount to perform spiral processing. In other words, the above-mentioned end mill 4
While always moving along the spiral locus b, machining without an approach with an angle is always performed.

The above-mentioned end mill 4 controlled by NC is about 6
While rotating at 00 to 1000 rpm, it moves at a moving speed of about 200 to 300 mm / min along the spiral locus b. At the time of cutting, the moving speed of the end mill 4 is set lower than at the time of other cutting. 4 to FIG.
As shown in FIGS. 7 and 8, the cutting is started by moving from obliquely upward to obliquely downward. The end mill 4 set to a low speed at the time of cutting contact (especially before and after the first touch) moves at a normal moving speed (about 200 to 300 mm / min) after its processing is stabilized.

That is, when cutting is started by moving the end mill 4 from obliquely upward to obliquely downward as shown in FIG. 8 at the time of cutting abutment, the outer periphery and the bottom surface of the main blade 6 and the sub-blade 7 are deeply dug e. , And the load urging force in the bending direction of the end mill 4 with respect to the shaft 5 is reduced, so that the resistance to the end mill 4 at the start of cutting can be reduced.

When cutting is started by moving the end mill 4 from obliquely downward to obliquely upward as shown in FIG. 9 at the time of cutting, only the outer peripheries of the main blade 6 and the sub-blade 7 come into contact with the deep dug portion e. Since the load biasing force in the bending direction of the end mill 4 with respect to the shaft 5 becomes large, the configuration shown in FIG.

In addition, the end mill 4 described above is used in FIGS.
When the helical movement is made along the helical locus b shown in FIG. 7, the upward movement (slant movement from the left to the right in FIGS. 6, 7, and 9) in one round of the helical movement is processed. The locus is set to be parallel to the curve 10 of FIG.

In other words, by making the movement obliquely upward as a trajectory along the processing shape, when cutting is performed with a constant cutting depth, the movement diagonally downward (rightward in FIGS. 6, 7 and 8). (Left slant movement), the inclination of the movement trajectory becomes gentler when moving obliquely upward, and therefore, it is urged against the shaft 5 of the end mill 4 as shown in FIG. The load in the bending direction is reduced as much as possible, and smooth cutting can be performed.

Therefore, when the above-described deep digging portion e is cut in the die blank 3 after the completion of the second large / medium roughing shown in FIG. 3, the NC-controlled end mill 4 is obliquely shown in FIGS. Set at the upper point b0, about 600-1000
The deep excavation part e is cut at a constant cutting amount while being moved obliquely downward along the spiral locus b while rotating at rpm.

When the end mill 4 reaches the end b1 of the trajectory obliquely downward, the end mill 4 is moved in the lateral direction in accordance with the shape of the deep digging portion e, and then is moved obliquely downward along the trajectory of this end mill 4. While moving obliquely upward from above, the deep digging portion e is cut again with a constant cutting amount, and the entire spiral area (the entire area of one processing portion) corresponding to the processing shape is cut by one round of the spiral movement.

When the end mill 4 reaches the end b2 of the trajectory diagonally above and completes one round of the spiral movement of the end mill 4, the same operation as described above is repeated to make a constant cut along the spiral trajectory b a plurality of times. Run and end mill 4
The final cutting according to makes a round along the curve 10 of the processing shape. In addition, the mold material which has been subjected to the spiral processing along the shape as described above is subjected to finish processing for completely removing the remaining margin a in the next step, and becomes a mold for plastic bumper molding.

As described above, according to the die cutting method of the above embodiment, the cutting blades (the main blade 6 and the sub-
Milling tool (see end mill 4)
The above-described relieving means relieves the load on the milling tool (see the end mill 4) at the time of the cutting abutment on the die blank 3. Moreover, since the cutting contact portion is cut by the spiral processing in which the above-mentioned milling tool (see the end mill 4) is moved while being cut along the spiral locus b, the load on the milling tool (see the end mill 4) is surely and securely reduced. Cutting can be quickly performed to a predetermined shape, and the uncut portion (remaining allowance) is reduced, so that the finishing process in the next step is facilitated. Further, since the end mill 4 having a small diameter can be used as a milling tool by the above-mentioned spiral machining, unlike the vertical mill used for thrust machining, cutting of a corner portion or a groove portion can be easily performed. .

Further, when processing into a mold shape having a curved contour (see the mold surface 9), the above-mentioned milling tool (see the end mill 4) along this curved shape (see the shape of the curve 10 on the mold surface 9). ) Is spirally moved and spirally processed, which has the effect of further reducing the uncut portion. In addition, since it can be processed spirally with a constant cutting amount corresponding to the curved surface of the product shape, air cut is reduced. In addition, processing efficiency can be improved.

In addition, the above-mentioned relaxation means moves the milling tool (see end mill 4) obliquely downward from above as shown in FIG. 8 to start cutting. There is an effect that the load bias in the bending direction is reduced, and the resistance to the milling tool (see the end mill 4) at the start of cutting can be reduced. When cutting is started by moving the end mill 4 obliquely downward from above in the opposite direction, the load bias in the bending direction with respect to the shaft 5 of the end mill 4 increases. The generation of bending stress on the shaft 5 of 4 can be greatly reduced.

Further, the above-mentioned relaxation means reduces the moving speed of the milling tool (see the end mill 4) at the time of cutting contact as compared with the other cutting operations. This has the effect of reducing the load on the device.

Further, since the above-mentioned movement (see FIG. 9) of the milling tool (see end mill 4) moves obliquely upward during the spiral movement of the milling tool (see FIG. 9), the path follows the machining shape.
When cutting is performed with a constant cutting amount, the inclination of the movement trajectory becomes gentler when moving obliquely upward (see FIG. 9) than when moving obliquely downward (see FIG. 8). For this reason,
The load in the bending direction urged against the shaft 5 of the milling tool (see the end mill 4) is reduced as much as possible, so that there is an effect that a smooth cutting process can be performed.

Furthermore, since the final cutting by the above-mentioned milling tool (see the end mill 4) makes one round along the machining shape, the uncut portion (remaining allowance) can be further reduced, and the medium roughing can be performed. There is an effect that simplification can be achieved.

On the other hand, as the above-mentioned relaxing means, means for starting cutting with a milling tool (see the end mill 4) from a place having a large curvature (a part with a gentle curve) may be used. There is an effect that the load on the milling tool (see the end mill 4) at the start can be reduced.

In the correspondence between the structure of the present invention and the above-described embodiment, the mold of the present invention corresponds to the plastic bumper molding mold of the embodiment. The milling tool corresponds to the end mill 4, and the present invention is not limited to the configuration of the above embodiment.

For example, in the above-described embodiment, the spiral locus b suitable for spirally processing the deeply dug portion e along the shape has been exemplified. However, the pattern of the spiral locus b is selected as an arbitrary pattern suitable for the cutting portion. be able to.

[Brief description of the drawings]

FIG. 1 is a perspective view of a die material after gas fusing used in the die cutting method of the present invention.

FIG. 2 is a schematic perspective view of a mold material after a first rough machining is completed.

FIG. 3 is a schematic perspective view of a mold material after completion of a second rough working.

FIG. 4 is a partial front view of an end mill used in the die cutting method of the present invention.

FIG. 5 is a bottom view of the end mill.

FIG. 6 is an explanatory view showing a cutting method for a mold according to the present invention.

FIG. 7 is an explanatory view showing a spiral locus of an end mill.

FIG. 8 is an explanatory diagram showing a movement from diagonally above to diagonally below.

FIG. 9 is an explanatory view showing a movement from diagonally lower to diagonally upper.

FIG. 10 is an explanatory view showing a conventional oblique punching method.

FIG. 11 is a sectional view showing a saw saw by a conventional method.

[Explanation of symbols]

 3: Mold material 4: End mill (milling tool) 6: Main blade (cutting blade) 7: Secondary blade (cutting blade) b: Spiral locus

Claims (7)

[Claims] 1. A method for cutting a mold material by moving a milling tool to form a mold, comprising: a milling tool provided with a cutting blade on an outer periphery and a bottom surface; When the tool abuts on the mold material, the milling tool is provided with mitigation means for reducing the load on the milling tool, and the cutting abutment portion is cut by spiral machining in which the milling tool is spirally moved along the machining shape. Die cutting method. 2. A method for cutting a mold for machining into a mold shape having a curved contour, wherein the milling tool is spirally moved along the curved shape to perform spiral machining.
The cutting method of the described mold. 3. The die cutting method according to claim 1, wherein the relaxing means starts the cutting by moving the milling tool from obliquely upward to obliquely downward. 4. The method according to claim 1, wherein said relaxing means starts cutting with a milling tool from a location having a large curvature. 5. The die cutting method according to claim 1, wherein said relaxing means reduces the moving speed of the milling tool at the time of cutting contact as compared with other cutting. 6. The die cutting method according to claim 1, wherein, during one round of the helical movement of the milling tool, the upward movement of the milling tool is a locus along a processing shape. 7. The method according to claim 1, wherein the final cutting by the milling tool makes one round along the machining shape.