JP6872872B2 - Method of machining a conical surface using a rod-shaped tool - Google Patents

Description

The present invention relates to a method for processing a conical surface using a rod-shaped tool, and particularly to an improvement in shaving marks on the conical surface.

Conventionally, it has been known to cut a workpiece using a small-diameter end mill as a rod-shaped tool. The smaller the diameter of the end mill, the more likely it is that the tip will vibrate or bend.

Advances in technology have made it possible to reduce the diameter of end mills (see, for example, Patent Document 1), and this ultra-small diameter end mill can process the surface of dies and the like for molding optical parts. It has become like. For example, as shown in FIG. 4, the conical surface 3 of the mold 2 for forming the base portion of the light emitting diode is processed.

Japanese Unexamined Patent Publication No. 2007-185736

However, in the method of processing a conical surface using an ultra-fine end mill, conventionally, the end mill is rotated and the feed direction is set to the circumferential direction of the center of the mold, and the tapered conical surface is processed while gradually moving up and down. I was doing (circumferential processing).

Then, since the contact portion of the end mill with respect to the workpiece becomes a point contact, it becomes difficult to perform stable machining because it becomes a rubbing state, and the center of the mold is set as the center of the circle on the tapered conical surface. Rippled cutting marks are generated. For example, a cutting mark having an arithmetic mean roughness Ra = 0.63 μm remains, and if a reflector is molded using this mold, there is a possibility that a problem may occur in terms of quality as an optical component.

Since the end mill tends to bend with respect to a force in the radial direction but is strong against a force in the axial direction, it is conceivable to cut with an end mill that rotates while moving up and down along a tapered conical surface. However, even in this case, since an ultra-fine end mill is used, bending occurs due to a reaction force during cutting.

Specifically, as shown in FIG. 5, while applying the resultant force F3 between the rotational force F1 of the end mill 1 and the feed force F2 of the tool, a shaving mark including a ridge 5 extending vertically due to a previous process such as roughing is applied. A finishing process is performed to eliminate the shaving marks. There is a problem that the end mill 1 is greatly bent in the direction opposite to the rotation direction due to the reaction force F4 (shown by a broken line in FIG. 5) when the shaving marks are cut, and the shaving marks cannot be cut cleanly. This problem is the same for small-diameter rod-shaped tools provided with a grindstone such as an electrodeposited diamond at the tip.

The present invention has been made in view of this point, and an object of the present invention is to make as little shaving marks as possible on the surface even when shaving a conical surface with a rod-shaped tool having an extremely small diameter. It is in.

In order to achieve the above object, in the present invention, when shaving the conical surface while feeding it up and down, the rod-shaped tool is fed up and down at a position slightly shifted from the original feeding direction.

Specifically, in the first invention, a method of machining a conical surface using a rod-shaped tool is premised.
The above processing method is
A roughing process in which the rotating rod-shaped tool is sequentially moved in the circumferential direction of the conical surface of the work at predetermined intervals and sent in the height direction to repeat roughing.
The rod-shaped tool that rotates with respect to the groove-shaped cutting mark extending in the height direction remaining on the conical surface by the roughing step with respect to the width direction center of the groove-shaped cutting mark is slightly shifted in the circumferential direction. It includes a finishing process in which cutting is performed while feeding along a direction, and a finishing process in which the cutting is sequentially repeated while moving in the circumferential direction and changing the position.

According to the above configuration, when cutting or grinding a conical surface using an end mill or a rod-shaped tool provided with an electrodeposited diamond at the tip, rough cutting while feeding in the height direction produces groove-shaped cutting marks in the height direction. Although it remains, the cutting marks are reduced in the finishing process. At that time, by intentionally shifting the rod-shaped tool from the center of the cutting mark in the width direction, the force applied to the rod-shaped tool can be adjusted so that the rod-shaped tool does not bend more than usual. The rod-shaped tool includes not only a cutting tool such as an end mill but also a grinding tool provided with a grindstone at the tip.

In the second invention, in the first invention,
In the finishing process, the rod-shaped tool is shifted to the side opposite to the rotation direction so that the allowance on the rotation direction side of the rod-shaped tool in the groove-shaped cutting mark is reduced.

According to the above configuration, the allowance on the rotation direction side is reduced, so the reaction force generated with respect to the resultant force of the rotational force and the feed force applied to the rod-shaped tool is smaller than when cutting at the center of the cutting mark in the width direction. Become. As a result, the amount of deflection of the rod-shaped tool is reduced.

In the third invention, in the first or second invention,
In the roughing process, only the upper end of the conical surface, which starts to be cut at the shifted position in the finishing process, is cut before moving to the next roughing position.

According to the above configuration, the effect of preventing bending due to the shift of the cutting position cannot be obtained at the start of cutting in the finishing process. Therefore, by cutting the start of cutting in advance in roughing, the rod-shaped tool can be used at the beginning of cutting. The shape guide function can be provided, and the bending of the rod-shaped tool at the start of cutting can be prevented.

In the fourth invention, in any one of the first to third inventions,
The shift amount in the finishing process is calculated from the product of the resistance to be cut, the depth of cut, and the feed amount.

According to the above configuration, the shift amount is set by estimating the deflection of the rod-shaped tool from the rigidity of the rod-shaped tool.

As described above, according to the present invention, a rod-shaped tool that rotates at a position slightly shifted with respect to the center of the width direction of the cutting mark due to rough machining is sent in the height direction to perform cutting, thereby forming a rod shape having an extremely small diameter. Even when cutting a conical surface with a tool, it is possible to leave as few shaving marks on the surface as possible.

It is a perspective view which shows the finishing process in the process of processing a conical surface using an end mill. It is a top view which shows the finishing process in the process of processing a conical surface using an end mill. It is a front view which shows the finishing process in the process of processing a conical surface using an end mill. It is a perspective view which shows the mold. It is the schematic which shows the load applied to the end mill.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 4 show a state of processing the conical surface 2 using the end mill 1 as a rod-shaped tool according to the embodiment of the present invention. As the end mill 1, the one having an extremely small diameter of about 2 mm as in Patent Document 1 will be described, but the end mill 1 may have an outer diameter smaller or larger than that. As a work, for example, a mold 2 (for example, shown in FIG. 4) for forming a base of a light emitting diode will be described as an example.

Specifically, in the method of processing the conical surface 2 using the end mill 1 of the present embodiment, first, in the roughing process, the rotating end mill 1 is sequentially spaced in the circumferential direction of the conical surface 3 of the mold 2. The roughing process is repeated by feeding in the height direction (the feed direction is indicated by the arrow G) while changing the position by moving with a gap. The interval in the circumferential direction is set so as to divide the entire circumference 360 ° of the conical surface 3 into equal parts, for example. For example, on the first lap, it is cut by dividing it into 9 parts of 40 ° each, then it is divided into equal parts at the position of 20 °, which is exactly half of that, and it is sent in the height direction while gradually shifting to a narrower position for cutting. I do. As shown in FIG. 2, when the conical surface 3 is cut by the end mill 1, a groove-shaped cutting mark 4 is formed on the conical surface 3 after cutting, and ridges 5 are formed on both sides of the groove-shaped cutting mark 4. Will be done. By feeding the end mill 1 in the height direction while shifting in the circumferential direction, the ridges 5 of vertical lines corresponding to the number of divisions are generated.

In this roughing process, as shown by the broken line in FIG. 2, before moving to the next roughing position, only the upper end of the conical surface 3 which starts to be cut at the shifted position in the finishing processing step described later is cut. You may. That is, since the bending start prevention effect due to the shift cannot be obtained at the start of shaving in the finishing process, the shape guide function of the rod-shaped tool at the start of shaving of the rod-shaped tool is provided by shaving the start of shaving in advance in the roughing. It can be left in place and the bending of the end mill 1 at the start of cutting can be prevented.

Next, in the finishing process, the end mill 1 that rotates with respect to the center of the groove-shaped cutting mark 4 in the width direction is circled with respect to the groove-shaped cutting mark 4 extending in the height direction remaining on the conical surface 3 due to the roughing process. Cutting is performed while feeding along the feeding direction slightly shifted in the direction. This finishing process is sequentially repeated while moving in the circumferential direction and changing the position in the same manner as in the roughing process. In this finishing process, the end mill 1 is shifted to the side opposite to the rotation direction so that the allowance on the rotation direction side of the end mill 1 is reduced. In the drawing, the cutting mark 4 is exaggerated, but in reality, the cutting allowance is about 2 μm, and the ridge 5 does not protrude so much. This shift amount S is calculated from, for example, the product of the resistance to be cut, the depth of cut, and the feed amount. That is, the deflection of the end mill 1 is estimated from the rigidity of the end mill 1 and set as the shift amount S (actually, the value of the angle). This may be obtained empirically by confirming the effect with the actually assumed shift amount S.

As described above, when the conical surface 3 is ground, if roughing is performed while feeding the conical surface 3 in the height direction, a groove-shaped cutting mark 4 remains in the height direction, but the cutting mark 4 is reduced in the finishing process. At that time, since the position of the end mill 1 is intentionally changed by the shift amount S from the center of the cutting mark 4 in the width direction, the end mill 1 can be prevented from bending more than usual. That is, since the allowance on the rotation direction side is decreasing and the allowance on the opposite side to the rotation direction is increasing, the reaction force generated with respect to the resultant force F3 of the rotational force F1 and the feed force F2 applied to the end mill 1 is increased. It receives F4, but its force is canceled by the reaction force when cutting the allowance on the opposite side of the rotation direction and becomes smaller. In other words, by reducing the allowance on the rotation direction side, the load is reduced, and by increasing the takeover allowance on the opposite side in the rotation direction, a backup effect due to the load can be obtained. Therefore, the amount of deflection of the end mill 1 is significantly reduced.

When the surface roughness of the conical surface 3 when actually cutting with this shift method was measured, it was found that the conventional method of revolving in the circumferential direction and gradually grinding in the height direction (circumferential processing method) was used. It was confirmed that Ra = 0.63 μm was changed to Ra = 0.01 μm, and an extremely large effect was obtained.

Therefore, according to the method for processing the conical surface 3 using the end mill 1 according to the present embodiment, even when the conical surface 3 is scraped by the end mill 1 having an extremely small diameter, the scraping marks should be kept as little as possible on the surface. Can be done.

(Other embodiments)
The present invention may have the following configuration with respect to the above embodiment.

That is, in the above embodiment, as the work, the mold 2 for forming the base of the light emitting diode has been described as an example, but even if the mold 2 is not such a mold 2, it has at least a processed surface of a conical surface 3. If so, it is not particularly limited.

It should be noted that the above embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its applications and applications.

That is, in the above embodiment, the rod-shaped tool is an end mill, but for example, a grinding tool having an electrodeposition diamond at the tip and having a diameter of about 0.05 mm may be used. The same effect can be obtained even when grinding using this grinding tool.

1 End mill (rod-shaped tool)
2 LED mold (work)
3 Conical surface
4 Groove-shaped cutting marks
5 ridges

Claims (4)

In the method of machining a conical surface using a rod-shaped tool, which processes the tapered conical surface of the work while pressing the rod-shaped tool in the axial direction.
A roughing process in which the above-mentioned rotating rod-shaped tool is sequentially sent in the height direction while changing the position at intervals in the circumferential direction of the conical surface of the work to repeat roughing.
With respect to the groove-shaped cutting mark extending in the height direction remaining on the conical surface by the roughing step, the axial center of the rod-shaped tool is relative to the circumferential direction with respect to the width direction center of the groove-shaped cutting mark. The position is changed, the allowance on the rotation direction side is reduced, the allowance on the side opposite to the rotation direction is increased, and the reaction force generated with respect to the resultant force of the rotational force and the feed force applied to the rod-shaped tool is canceled and the rod-shaped tool is bent. A rod-shaped tool characterized in that the finishing process of sending the above-mentioned rod-shaped tool that rotates while suppressing the above-mentioned is sent in the height direction to perform cutting is sequentially repeated while moving in the circumferential direction and changing the position. Method of processing a conical surface using. In the method of machining a conical surface using a rod-shaped tool, which processes the tapered conical surface of the work while pressing the rod-shaped tool in the axial direction.
A roughing process in which the above-mentioned rotating rod-shaped tool is sequentially sent in the height direction while changing the position at intervals in the circumferential direction of the conical surface of the work to repeat roughing.
The rod-shaped tool that rotates at a position slightly shifted with respect to the center of the groove-shaped cutting mark in the width direction with respect to the groove-shaped cutting mark extending in the height direction remaining on the conical surface by the roughing step in the height direction. Including a finishing process in which the finishing process of sending to and cutting is repeated in sequence while moving in the circumferential direction and changing the position.
In the finishing process, a force is applied so as to reduce the allowance on the rotation direction side of the rod-shaped tool in the groove-shaped cutting mark, and the force is applied in the direction opposite to the bending direction of the rod-shaped tool due to the degree of bending of the rod-shaped tool. As described above, the rod-shaped tool is configured to shift from the center of the groove-shaped cutting mark in the width direction to the side opposite to the rotation direction.
A method for machining a conical surface using a rod-shaped tool, wherein the shift amount of the rod-shaped tool is determined by estimating the deflection of the rod-shaped tool from the rigidity of the rod-shaped tool. In the method of machining a conical surface using a rod-shaped tool,
A roughing process in which the above-mentioned rotating rod-shaped tool is sequentially sent in the height direction while changing the position at intervals in the circumferential direction of the conical surface of the work to repeat roughing.
The rod-shaped tool that rotates at a position slightly shifted with respect to the center of the groove-shaped cutting mark in the width direction with respect to the groove-shaped cutting mark extending in the height direction remaining on the conical surface by the roughing step in the height direction. Including a finishing process in which the finishing process of sending to and cutting is repeated in sequence while moving in the circumferential direction and changing the position.
In the roughing process, a cone using a rod-shaped tool is characterized in that only the upper end of the conical surface, which starts to be cut at the shifted position in the finishing process, is cut before moving to the next roughing position. Surface processing method. In the method for processing a conical surface using the rod-shaped tool according to any one of claims 1 to 3.
Method for processing a conical surface with a rod-shaped tool, characterized in that the output product or we calculated the amount of feed and the cutting resistance and the depth of cut a shift amount in the finishing process.

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