KR101998709B1 - Twist Drill for Precision Drilling - Google Patents

Abstract

The present invention relates to a drill body having a drill body and a drill body, wherein the drill body is provided with a guide portion for guiding chip discharge and a secondary blade portion in an entry region toward the workpiece, A twist drill comprising a plurality of cutting lands extending in a twisted form on an outer periphery and formed in a conical shape at a front end thereof to form a cutting end capable of cutting a workpiece, A pair of cutting margins formed corresponding to the two cutting lands of the cutting lands at an end of the cutting lands, each of the cutting margins forming an inclined surface for cutting contact, the two being disposed at symmetrical positions with respect to each other; A pair of auxiliary margins formed in an outer side of the cutting edge in a direction orthogonal to the cutting margin and corresponding to two cutting lands different from the cutting margin; And a chip guide end which is recessed inward corresponding to the gap between the cutting margin and the auxiliary margin and which guides chip inflow corresponding to the chip discharge path.

Description

[0002] Twist Drill for Precision Drilling [

The present invention relates to a twist drill for precision machining. More particularly, the present invention relates to a twist drill for precision machining, and more particularly, to a method of manufacturing a twist drill for accurately machining a hole while maintaining the roundness and straightness for hole machining, The present invention relates to a twist drill for precision machining.

In general, drills are mainly used to drill holes in metal molds or parts made of materials such as wood. They are usually applied to cemented carbide and diamond based on the material of high-speed steel. They are used in various types of drilling machines, Drills, and hand drills.

The conventional drill includes a shank constituting an overall body portion, an outer peripheral cutting edge and a chip discharge groove extending in a forward direction of the shank so as to be capable of hole cutting at an outer periphery thereof and a chip discharge groove, And a cutting edge portion forming a conical shape and forming a margin portion for cutting the workpiece.

However, in the conventional drill, since the marginal portion of the cutting edge portion is formed with two marginal portions, there is a problem that the marginal phenomenon easily occurs at the center of the tip of the drill during cutting, and roundness and life are deteriorated at the time of machining.

Accordingly, in order to precisely dimension the machining hole in the cutting operation due to the drill, a structural design is required in order to minimize the trembling during machining.

As a conventional technique disclosed to solve the above problems, Korean Patent Registration No. 628885 (Sep. 20, 2006)) discloses a carbide step drill having an equally spaced drill bit step, The tip angle consists of 176 ± 2 °; The drill bit is formed with four margins. Thus, it is possible to extend the service life of the drill and to maintain the straightness of the drill, and to provide a high-quality thread hole machining with accurate guidance in the drilling direction. Drills are known.

However, in the case of the above-mentioned conventional technique, the roundness and the tremble phenomenon are partially improved at the time of machining by forming the four margins of the drill bit. However, since processing feedback is performed as compared with the drill having two existing margin portions, There is a problem that the lifetime is naturally lowered and the chip is not smoothly discharged during processing.

In addition, recently, the marginal portion of the drill tip has been developed and used as a structure having six holes. However, since the six margins repeatedly contact the workpiece during machining, there is a problem that over- .

KR Patent Registration No. 10-0628885 (September 20, 2006)

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a semiconductor device which has two margins at the front end thereof and is capable of holding a crisscross cutting edge, thereby improving machining roundness and precision while reducing machining contact resistance, And to provide a twist drill for precision machining that can smoothly discharge cutting chips.

The twist drill for precision machining proposed by the present invention comprises a plurality of cutting lands and chip discharge paths extending in the longitudinal direction on the front side of the drill main body and formed in a twisted form on the outer peripheral edge and protruding in a conical shape at the front end A twist drill constituting a cutting end capable of cutting a workpiece, the twist drill being formed at the cutting end in correspondence with the two cutting lands of the cutting land and forming an inclined surface for cutting contact, the two being disposed at mutually symmetrical positions A pair of cutting margins; A pair of auxiliary margins formed in an outer side of the cutting edge in a direction orthogonal to the cutting margin and corresponding to two cutting lands different from the cutting margin; And a chip guiding end which is recessed inwardly corresponding to the gap between the cutting margin and the sub-margin and guiding chip inflow corresponding to the chip discharging path.

And an initial cutting groove portion corresponding to the forward end of the cutting end portion and guiding the chip discharge toward the chip discharge path together with the initial cutting operation on the workpiece, And a curved surface of an arc shape is formed on one side.

The cutting margin and the auxiliary margin each have a cutting edge protruding outward by 5 to 10 mm in correspondence with the cutting land for machining an inner diameter of the cutting hole with respect to the workpiece.

The auxiliary margin forms an inclined surface having an inclination angle equal to the cutting margin and has a contact area of 1/4 to 1/5 of the area of the cutting margin.

Wherein a slant angle between a pair of cutting margins and a pair of auxiliary margins at the cutting end is 140 to 145 占 respectively, and the auxiliary margin is disposed rearward with respect to the cutting area of the cutting margin .

The chip guiding end is provided with a chip guide surface formed between the cutting margin and the sub-margin to form an inclined guide surface inclined rearward corresponding to the chip discharge path.

According to the twist drill for precision machining according to the present invention, two auxiliary margins are formed at the forward end toward the workpiece, with two basic cutting margins and chip guide ends recessed inward in the orthogonal direction of the cutting margin. , It reduces the machining contact resistance during drill rotation to prevent overload or wrinkle phenomenon, precise roundness at machining, shorten machining time, and drill itself And the processability of the product can be improved while prolonging phosphorus and life span.

1 is a perspective view showing an embodiment according to the present invention;
2 is a front view showing an embodiment according to the present invention;
3 is a side view showing an embodiment according to the present invention.
4 is a front elevation view showing the cutting end in one embodiment according to the present invention;
FIG. 5 is an enlarged perspective view showing a cutting end in an embodiment according to the present invention. FIG.

The present invention relates to a drill body having a plurality of cutting lands and a chip discharge path extending in the longitudinal direction in the front of the drill main body and having a twisted shape on the outer periphery thereof and protruding in the form of a cone at the forward end, A pair of cutting margins formed at positions corresponding to the two cutting lands of the cutting lands at the cutting end and forming inclined surfaces for cutting contact, the two being disposed at mutually symmetrical positions; A pair of auxiliary margins formed in an outer side of the cutting edge in a direction orthogonal to the cutting margin and corresponding to two cutting lands different from the cutting margin; And a chip guide end which is recessed inwardly corresponding to the gap between the cutting margin and the auxiliary margin and which guides chip inflow corresponding to the chip discharge path.

Next, a preferred embodiment of a twist drill for precision machining according to the present invention will be described in detail with reference to the drawings.

1 and 2, an embodiment of a twist drill for precision machining according to the present invention includes a plurality of cutting lands 22 extending in the longitudinal direction in front of a drill main body 10, (20) and a chip discharge path (30), the cutting end (100) being formed in a conical shape protruding from a front end of the cutting end (100) A margin 110, an auxiliary margin 120, and a chip guide end 130.

As shown in FIG. 1, the cutting land 20 is formed to have a total of four vertically and horizontally and twisted twisted structures. The chip land 20 is divided into the chip discharge path 30, .

The chip discharge path 30 is formed in a gently curved surface between the cutting lands 20 so that the cutting chips can be smoothly discharged smoothly.

3 to 5, the cutting end 100 includes two cutting margins 110, two auxiliary margins 120 and a chip guide end 130, .

As shown in FIG. 3, the cutting margin 110 is formed in a substantially strip-like shape exposed frontward corresponding to two cutting lands 20 of the cutting lands 20, and two cutting margins 110 They are arranged in symmetrical positions with each other.

The cutting margin 110 is formed so as to be sharply protruded in correspondence with the workpiece and has a sloped surface which is in front contact with the surface, so that the cutting surface can be brought into contact with the workpiece.

In the cutting end 100, as shown in FIG. 4, a slanting angle? 1 between the pair of cutting margins 110 is 140 to 145 degrees. That is, when the angle of inclination? 1 between the cutting margins 110 is less than 140, the end of the cutting edge 100 is frequently deformed due to insufficient rigidity, shortening the service life of the product, If the inclination angle alpha 1 exceeds 145 deg., The initial machining efficiency toward the workpiece is lowered and the machining time is increased. Therefore, the inclination angle alpha 1 between the cutoffs is preferably 140 to 145 deg. So that the durability and machining efficiency of the tip end of the drill can be improved.

The width of the cutting margin 110 is gradually increased toward the outer circumferential direction. That is, one surface of the cutting margin 110 which contacts the workpiece during cutting is formed to have an inclination angle? 2 of 2 to 3 degrees outward from the center of the cutting edge 100 toward the outer periphery, It is possible to guide the movement of the chip toward the chip discharge path 30 while preventing dispersion of the workpiece on the cutting chip, thereby achieving efficient discharge.

The auxiliary margin 120 functions to form a cutting support point in four directions in order to improve the shaking and roundness of the product together with the cutting margin 110.

3 to 5, the auxiliary margin 120 is formed on the cutting end 100 in a direction perpendicular to the cutting margin 110.

3, the auxiliary margin 120 is exposed on the cutting edge 100 corresponding to two cutting lands 20 which are different from the cutting margin 110 of the cutting lands 20 When the two auxiliary margins 120 are formed as a pair, the auxiliary margins 120 are formed so as to be disposed at symmetrical positions with respect to each other.

The auxiliary margin 120 is partially formed with the chip guide end 130 at the outer end at the cutting end 100.

As shown in FIG. 4, the auxiliary margin 120 is formed in the cutting end 100 to have an inclined surface having the same inclination angle as that of the cutting margin 110, And the blade angle is formed to be 140 to 145 degrees. That is, even when the angle of inclination between the auxiliary margins 120 is equal to the angle of inclination? 1 between the cutting margins, it is possible to precisely grasp the roundness of the cutting process while assisting the cutting process of the cutting margin 110 effectively. It is possible to efficiently demonstrate the functionality for the user.

The auxiliary margin 120 is disposed behind the cutting area of the cutting margin 110 so that sufficient initial cutting operation of the cutting margin 110 can be progressed, So that the work roundness can be immediately obtained.

The auxiliary margin 120 is formed on the outer side of the chip guide end 130. The auxiliary margin 120 has a contact area of 1/4 to 1/5 of the area of the cutting margin 110, .

When the area of the auxiliary margin 120 exceeds 1/4 of the area of the cutting margin 110, the area of the chip guide end 130 is relatively reduced by the area of the auxiliary margin 120, The machining contact resistance with the workpiece is increased to adversely affect the lifetime and vibration of the drill itself. If the area of the auxiliary margin 120 is less than 1/5 of the area of the cutting margin 110, The workability and roundness become poor.

The cutting margin 110 and the auxiliary margin 120 each have cutting edges 115 and 125 protruding outwardly corresponding to the cutting lands 20 for machining an inner diameter of the cutting hole with respect to the workpiece.

The cutting edges 115 and 125 are formed to protrude 5 to 10 mm on the outer periphery of the cutting margin 110 and the auxiliary margin 120. That is, when the cutting steps 115 and 125 are formed to be less than 5 mm, it is difficult to maintain an appropriate life according to the degree of wear. When the cutting steps 115 and 125 are formed by more than 10 mm, It is difficult to maintain the rigidity according to the present invention.

In addition, the cutting end portion 100 forms an initial cutting groove portion 140 that is formed in a cutting contactable manner corresponding to the forward end.

The initial cutting grooves 140 are formed at the forward end of the cutting end 100 facing the workpiece and serve to guide chip discharge toward the chip discharge path 30 along with initial cutting of the workpiece .

The initial cut grooves 140 are recessed inwardly and have a depth of 5 to 10 mm, and curved surfaces 141 of an arc shape are formed on one side. That is, the initial cutting groove 140 secures a chip discharging path in a limited space when the sharp tip of the cutting end 100 makes initial contact with the workpiece, thereby achieving smooth chip discharge and improving the machining performance It is possible.

The chip guide end 130 serves to guide the chip inflow toward the chip discharge path 30 while securing a space by separating the contact of the cutting end 100 with respect to the workpiece.

The front end of the chip guide end 130 has a concave shape rearward or inward and is formed corresponding to the gap between the cutting margin 110 and the auxiliary margin 120.

A contact guide surface 135 for guiding chip inflow to the chip discharge path 30 is formed in the rear of the chip guide end 130.

The contact guide surface 135 of the chip guide end 130 is provided with an inclined guide surface 135a which is formed at a front side and is inclined toward the rear outer side corresponding to the chip discharge path 30 at the chip guide end 130 And a chip guide surface 135b extending rearward from one end of the inclined guide surface 135a and laterally connected between the cutting margin 110 and the auxiliary margin 120 to form a curved surface. do.

The inclined guide surface 135a has a tilt angle β of 20 to 45 ° toward the rear with respect to the tip of the cutting edge 100.

In this case, the inclined guide surface 135a is formed to have an inclination in a lateral direction, that is, a direction connecting the auxiliary margin 120 with the cutting margin 110. [ For example, the angle β of the inclined guide surface 135a on the cutting margin 110 side is 20 to 25 ° with respect to the tip of the cutting edge 100, and the tip of the cutting edge 100 is defined as a reference And the angle? Of the inclined guide surface 135a on the sub-margin 120 side is formed to be 40 to 45 degrees.

The chip guide surface 135b forms a wave-like curved surface in the lateral direction toward the auxiliary margin 120 from the cutting margin 110. [ That is, the chip guide surface 135b forms a convex curved surface toward the outside corresponding to the cutting margin 110 to reinforce the impact buffering and durability applied to the cutting margin 110, and the chip guide surface 135b The chip discharge path 30 is formed by forming a concave curved surface inward corresponding to the auxiliary margin 120 so that smooth chip discharge due to contact with the auxiliary margin 120 can be achieved.

That is, according to the twist drill for precision machining according to the present invention configured as described above, the tip ends of the chip guide teeth (110) which are recessed inward in the orthogonal direction of the cutting margin (110) along with the two basic cutting margins 130 are formed, it is possible to prevent the product from being shaken from the dispersion and support in four directions, to reduce the machining contact resistance during drilling and to prevent overloading or wrinkling phenomenon, It is possible to precisely capture the roundness at the time of machining, shorten the machining time, and improve the workability of the product while prolonging the roughness and life of the drill itself.

Although the preferred embodiments of the twist drill for precision machining according to the present invention have been described above, the present invention is not limited thereto, but may be modified and embodied within the scope of the claims, the detailed description of the invention, and the accompanying drawings , Which are also within the scope of the present invention.

10: Drill body 20: Cutting land
30: chip discharge path 100: cutting end
110: cutting margin 120: auxiliary margin
115, 125: cutting edge 130: chip guide edge
135: contact guide surface 135a: inclined guide surface
135b: chip guide surface 140: initial cutting groove

Claims (6)

A plurality of cutting lands and a chip discharge path extending in the longitudinal direction in front of the drill main body and formed in a twisted shape on the outer periphery and protruding in a conical shape at the forward end to form a cutting end capable of cutting the workpiece A pair of cutting margins formed at positions corresponding to the two cutting lands of the cutting lands at the cutting end and forming inclined surfaces for cutting contact, the two being disposed at mutually symmetrical positions; A pair of auxiliary margins formed in an outer side of the cutting edge in a direction orthogonal to the cutting margin and corresponding to two cutting lands different from the cutting margin; And a chip guide step formed inwardly corresponding to the gap between the cutting margin and the auxiliary margin and guiding chip inflow corresponding to the chip discharge path,
And an initial cutting groove portion corresponding to the forward end of the cutting end portion and guiding the chip discharge toward the chip discharge path together with the initial cutting operation on the workpiece, A circular curved surface is formed on one side,
Wherein the cutting margin and the auxiliary margin each include a cutting edge protruding outward by 5 to 10 mm to correspond to the cutting land for machining an inner diameter of the cutting hole with respect to the workpiece,
Wherein the cutting margin is formed such that the width of the cutting margin gradually increases toward the outer circumferential direction, wherein one surface of the cutting margin, which is in contact with the workpiece during cutting, has an inclination angle of 2 to 3 degrees outward from the center of the cutting end toward the outer circumferential direction And is upwardly inclined,
Wherein the auxiliary margin forms an inclined surface having an inclination angle equal to the cutting margin and has a contact area of 1/4 to 1/5 of the area of the cutting margin,
Wherein a slant angle between a pair of cutting margins and a pair of auxiliary margins at the cutting end is 140 to 145 占 respectively, and the auxiliary margin is disposed behind the cutting area of the cutting margin ,
And a chip guiding surface formed between the cutting margin and the sub-margin to form an inclined guide surface inclined rearward corresponding to the chip discharge path,
Wherein the inclined guide surface has an inclination angle of 20 to 45 degrees with respect to the tip end of the cutting end, the angle of the inclined guide surface on the cutting margin side is 20 to 25 degrees with respect to the tip end of the cutting end, And an angle of the inclined guide surface on the side of the auxiliary margin is 40 to 45 degrees with respect to the tip of the cutting edge.
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