JP2018043336A - Processing method of conical surface of using rod-like tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a shaving trace from leaving on a surface as much as possible, even when shaving a conical surface by a rod-like tool of an extremely small diameter.SOLUTION: Rough processing is repeated by sending a rotating end mill 1 in the height direction while changing a position by successively opening an interval in the circumferential direction of a conical surface 3 of a work 2, and finish processing for cutting by sending the end mill 1 for rotating in a slightly shifted position to the center in its width direction to the height direction, is successively repeated while changing the position by moving in the circumferential direction to a groove-shaped cutting trace 4 of extending in the height direction of remaining on the conical surface 3 by this rough processing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for machining a conical surface using a rod-shaped tool, and more particularly to improvement of a scraped mark on the conical surface.

  Conventionally, it is 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 easier it is for the tip to vibrate and bend.

  Due to technological advances, the diameter of the end mill can be made smaller and smaller (see, for example, Patent Document 1), and the surface of a mold or the like for molding optical components can be processed by this ultra-small diameter end mill. It is like that. 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.

JP 2007-185736 A

  However, in the conventional conical surface machining method using an ultra-fine end mill, conventionally the end mill rotates and the feed direction is the circumferential direction of the mold center, and the tapered conical surface is machined while gradually moving up and down. I went (circumferential machining).

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

  The end mill is easy to bend with respect to the force in the radial direction, but is strong against the force in the axial direction. Therefore, it can be considered that the end mill is cut by an end mill that rotates while moving up and down along the tapered conical surface. However, even in this case, since an extremely fine end mill is used, bending due to a reaction force during cutting occurs.

  Specifically, as shown in FIG. 5, a cutting trace including a protrusion 5 extending vertically by a previous process such as roughing while applying a resultant force F3 of the rotational force F1 of the end mill 1 and the feed force F2 of the tool. Finishing is performed to remove the traces. 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 cutting the cutting trace, and the cutting trace cannot be cut cleanly. This problem is the same for a small-diameter bar-shaped tool having a grindstone such as an electrodeposition diamond at its tip.

  The present invention has been made in view of such a point, and the object of the present invention is to keep as little as possible a trace on the surface even when a conical surface is shaved with a rod tool having a very small diameter. It is in.

  In order to achieve the above object, in the present invention, when cutting while conical surfaces are fed up and down, the bar-shaped tool is fed up and down at a position slightly shifted from the original feed direction.

Specifically, in the first invention, on the premise of a conical surface machining method using a rod-shaped tool,
The above processing method is
A roughing step of repeating the roughing by sending the rotating rod-shaped tool in the height direction while sequentially moving the rod-shaped tool in the circumferential direction of the conical surface of the workpiece;
Feeding with a slight shift in the circumferential direction of the rod-shaped tool rotating with respect to the center in the width direction of the groove-shaped cutting trace with respect to the groove-shaped cutting trace extending in the height direction remaining on the conical surface by the roughing step A finishing process in which cutting is performed while feeding along a direction, and a finishing process is sequentially repeated while moving in the circumferential direction and changing the position.

  According to the above configuration, when a conical surface is cut or ground 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 results in a groove-shaped cutting trace in the height direction. Although it remains, the cutting trace is reduced in the finishing process. At that time, the bar-shaped tool is deliberately shifted from the center in the width direction of the cutting trace, thereby adjusting the force applied to the bar-shaped tool and preventing the bar-shaped tool from being bent more than usual. The rod-shaped tool includes not only a cutting tool such as an end mill but also a grinding tool having a grindstone provided at the tip.

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

  According to the above configuration, since the machining allowance on the rotational direction side is reduced, the reaction force generated against the resultant force of the rotational force applied to the rod-shaped tool and the feed force is also smaller than when cutting at the center in the width direction of the cutting trace. Become. As a result, the amount of deflection of the bar tool is reduced.

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

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

In a 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 cut amount and the feed amount.

  According to the above configuration, the shift amount is set by estimating the deflection of the bar-shaped tool from the rigidity of the bar-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 in the width direction of a cutting mark by rough machining is sent to the height direction to perform cutting, so that a rod shape with an extremely small diameter is obtained. Even when the conical surface is cut with a tool, it is possible to leave as little as possible a trace on the surface.

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

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

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

  Specifically, in the processing method of 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 placed at a predetermined interval in the circumferential direction of the conical surface 3 of the mold 2. While moving, the position is changed, and the roughing is repeated by feeding in the height direction (the feed direction is indicated by arrow G). The interval in the circumferential direction is set so that the entire circumference 360 ° of the conical surface 3 is equally divided. For example, on the first round, cut in 9 increments of 40 °, and then divide equally at 20 °, which is exactly half of that, and send by cutting in the height direction while gradually shifting the position to a narrower position. I do. As shown in FIG. 2, when the conical surface 3 is cut by the end mill 1, groove-shaped cutting traces 4 are formed on the conical surface 3 after cutting, and protrusions 5 are formed on both sides of the groove-shaped cutting trace 4. Is done. By feeding the end mill 1 in the height direction while shifting in the circumferential direction, vertical line ridges 5 corresponding to the number of divisions are generated.

  In this roughing process, as shown by a broken line in FIG. 2, before moving to the next roughing position, only the upper end of the conical surface 3 that starts cutting at the position shifted in the finishing process described later is shaved. May be. In other words, since the effect of preventing deflection due to shifting cannot be obtained at the beginning of cutting in finishing, the shape guide function of the rod-shaped tool at the beginning of cutting of the rod-shaped tool is given by cutting the beginning of cutting in rough machining in advance. 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 in the width direction of the groove-shaped cutting trace 4 is circumferentially arranged with respect to the groove-shaped cutting trace 4 extending in the height direction remaining on the conical surface 3 by the roughing process. Cutting is performed while feeding along the feeding direction slightly shifted in the direction. Similar to the roughing process, this finishing process is sequentially repeated while moving in the circumferential direction and changing the position. In this finishing process, the end mill 1 is shifted to the opposite side to the rotational direction so that the machining allowance on the rotational direction side of the end mill 1 is reduced. In the drawing, the cutting mark 4 is exaggeratedly written, but actually, the machining allowance is about 2 μm, and the protrusion 5 does not protrude so much. The shift amount S is calculated from, for example, the product of the resistance to be cut, the cut amount, and the feed amount. That is, the deflection of the end mill 1 is estimated from the rigidity of the end mill 1, and is 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 grinding is performed while feeding the conical surface 3 in the height direction, groove-like cutting traces 4 remain in the height direction, but the cutting traces 4 are 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 in the width direction of the cutting trace 4, the end mill 1 can be prevented from being bent more than usual. That is, the machining allowance on the rotational direction side is reduced, and conversely, the machining allowance on the side opposite to the rotational direction is increased, so that the reaction force generated against the resultant force F3 of the rotational force F1 and the feed force F2 applied to the end mill 1 Although F4 is received, the force is canceled and reduced by the reaction force when cutting the machining allowance on the side opposite to the rotation direction. In other words, by reducing the machining allowance on the rotation direction side, the load is reduced, and by increasing the machining allowance on the opposite side in the rotation direction, a backup effect due to the load can be obtained. For this reason, the amount of deflection of the end mill 1 is significantly reduced.

  When the surface roughness of the conical surface 3 was actually measured by cutting using this shift method, the conventional method of grinding in the height direction while revolving in the circumferential direction (circumferential machining method) Ra = 0.63 μm is Ra = 0.01 μm, and it was confirmed that an extremely large effect was obtained.

  Therefore, according to the processing method of 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 a very small diameter, as much as possible no trace is left on the surface. Can do.

(Other embodiments)
The present invention may be configured as follows with respect to the above embodiment.

  That is, in the said embodiment, although demonstrated about the metal mold | die 2 for shape | molding the stand of a light emitting diode as a workpiece | work, even if it is not such a metal mold | die 2, it has a processing surface of the conical surface 3 at least. If it is, it will not specifically limit.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or a use.

  That is, in the said embodiment, although the rod-shaped tool is made into the end mill, for example, the grinding tool about 0.05 mm in diameter in which the electrodeposition diamond was provided in the front-end | tip may be sufficient. Similar effects can be obtained even when grinding is performed using this grinding tool.

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

Claims (4)

In the conical surface machining method using a rod-shaped tool,
A roughing step of repeating the roughing by sending the rotating rod-shaped tool in the height direction while sequentially changing the position in the circumferential direction of the conical surface of the workpiece while changing the position;
The rod-shaped tool that rotates at a position slightly shifted with respect to the center of the groove-shaped cutting trace in the width direction with respect to the groove-shaped cutting trace extending in the height direction remaining on the conical surface by the roughing step in the height direction A finishing method for cutting a conical surface using a rod-shaped tool, comprising: a finishing process in which a finishing process for cutting by cutting is repeatedly performed while moving in a circumferential direction and changing a position. In the processing method of the conical surface using the rod-shaped tool according to claim 1,
A cone using a rod-shaped tool characterized in that, in the finishing process, the rod-shaped tool is shifted to the opposite side of the rotational direction so that a machining allowance on the rotational direction side of the rod-shaped tool in the groove-shaped cutting trace is reduced. Surface processing method. In the processing method of the conical surface using the rod-shaped tool according to claim 1 or 2,
In the roughing process, before moving to the next roughing position, only the upper end of the conical surface that starts cutting at the shifted position in the finishing process is shaved. Surface processing method. In the processing method of the conical surface using the rod-shaped tool as described in any one of Claim 1 to 3,
A method for machining a conical surface using a bar-shaped tool, wherein a shift amount in the finishing process is calculated from a product of a resistance to be cut, a cut amount, and a feed amount.

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