JP2008264979A - Rotary cutting tool for drilling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out rough working being a prepared hole working with one tool, and to further improve roundness of a hole formed on a workpiece. <P>SOLUTION: This rotary cutting tool for drilling satisfies all following conditions: (1) a body has a flute part the helix angle of which is 5 to 30 degrees; (2) a polycrystal diamond chip 4 is arranged as a slant blade on a margin part so as to run along it within a range of 0.2 mm; (3) a preceding blade part 6 is formed on the front side in the tool proceeding direction and a finishing blade part 7 is integrally formed on the rear side of the polycrystal diamond chip; and (4) central height H of blade chamfer parts 9, 11 is 0±0.2 mm. The tool also has capacity to roughly work as it can continuously work but not intermittently work though it is one piece of the tool, improves discharging efficiency of chips by lowering discharging resistance of the chips while parting the chips, thereby eliminates influence of the chips as much as possible in cutting, and further improves the roundness of the hole formed on the work. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotary cutting tool for drilling, such as a reamer and a drill, which is suitable for machining that can perform rough machining as typified by pilot hole machining and can also obtain a work quality suitable for finishing machining.

  Conventionally, there is JP-A-8-39350 as a technique in such a field. The reamer body described in the example of this publication has three tiers, a total of 10 polycrystalline diamond chips fixed to the body, and the first first stage 4 polycrystalline diamond chips have a front first cut. The blade portion and the second cutting blade (deburring blade) positioned outside the first blade are provided. The chip discharge groove of the body is parallel to the rotation axis, and the polycrystalline diamond chip is also in a positional relationship parallel to the rotation axis.

JP-A-8-39350

  However, in the above-described structure, even if burrs can be removed with the second cutting edge, there is no ability to perform rough machining represented by pilot hole machining. In addition, since the polycrystalline diamond chip and the chip discharge groove are in a positional relationship parallel to the rotation axis, the chip discharge resistance is high, and the four finishing blades act intermittently. There was a problem that it was difficult to improve the quality.

  The present invention provides a rotary cutting tool for drilling, which is capable of roughing as represented by pilot hole machining and further improving the roundness of a hole formed in a workpiece while being a single tool. The purpose is to provide.

In the rotary cutting tool for drilling according to the present invention, the rotary cutting tool for drilling provided with a polycrystalline diamond tip at the tip of the body,
The body has a flute portion with a twist angle of 5 to 30 °, and has a leading edge portion and a finish blade portion along a margin portion that forms an outer edge of the flute portion having a twist angle with respect to the tool axis. A crystalline diamond tip is disposed, and the center height of the polycrystalline diamond tip is 0 ± 0.2 mm.

  In the present invention, (1) the body has a flute portion with a twist angle of 5 to 30 degrees, and (2) a polycrystalline diamond tip is arranged as a slanted blade along the margin portion which is the outer edge of the flute portion, (3) In the polycrystalline diamond tip, the leading edge is integrally formed on the front side in the tool traveling direction, and the finishing edge is integrally formed on the rear side. (4) The center height of the polycrystalline diamond tip is 0 ± 0.2 mm. By satisfying the above conditions (1) to (4), the rotary cutting tool for drilling having a polycrystalline diamond tip in which the leading edge and the finishing edge are integrated is finished with rough machining. Machining can now be done with a single tool. (1)-(4) A tool that satisfies all of the above has the ability to perform rough machining because it is continuous machining rather than intermittent machining, and lowers the discharge resistance of the chips while cutting the chips, Since the chip discharge efficiency can be improved, the influence of the chips is eliminated as much as possible at the time of cutting, and the roundness of the holes formed in the workpiece can be further improved.

  The polycrystalline diamond tip has a leading blade portion having a first biting portion on the tip side in the tool traveling direction, and a substantially V-shaped or U-shaped shape positioned rearward in the tool traveling direction of the leading blade portion. And the finishing blade portion having the second biting portion located on the rear side of the Nusumi portion are integrated, and the inner end of the second biting portion is outside the first biting portion. The outer end of the second biting portion is positioned 0.25 to 0.5 mm radially outward from the outer end of the first biting portion, and is located on the inner side in the radial direction from the end. The length in the rotation axis direction from the outer end of the biting portion to the outer end of the second biting portion is 1 to 5 mm, and the finishing blade portion is rearward from the outer end of the second biting portion in the rotation axis. When it has a part extending 5 to 8 mm, the cutting ability as roughing and finishing Since the quality of Engineering to improve both, it is more preferred.

  When such a configuration is adopted, the diamond tip has high hardness because it is a polycrystalline diamond tip, and the cutting edge cannot be formed, and since it is an oblique blade, it is not intermittently cut, and the center height is controlled to 0 ± 0.2 mm. Since the cutting load on the leading edge is reduced because the cutting resistance is low, the first biting edge performs as a tool capable of roughing as represented by pilot hole machining. Furthermore, even with high-speed feeding, the cutting edge part on the inner end side of the second biting part is made by using a relief part that is a substantially V-shaped or U-shaped nuisance part. The cutting blade portion reliably removes the workpiece left by the leading blade, but the cutting load is lighter than the leading blade portion (the machining allowance is 0.5 to 1 mm in rotation diameter, and margin) Roundness along the part) It can be processed good and burrs hardly holes with high accuracy. Furthermore, since the finishing blade portion has an inclined blade portion of 5 to 8 mm in the rotation axis direction from the outer end of the second biting portion, the second biting portion of the finishing blade portion is worn and the workpiece Even when the cutting ability related to the quality is lowered, the tool function has a length that can restore the tool function by re-polishing.

  According to the present invention, although it is a single tool, rough machining represented by pilot hole machining is possible, and the roundness of the hole formed in the workpiece can be further improved.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a rotary cutting tool for drilling according to the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the rotary cutting tool 1 for drilling is a reamer with a drill suitable for machining a workpiece made of aluminum, magnesium, or the like, and has a body 2 made of cemented carbide. The body 2 is provided with a flute portion (chip discharge groove) 3a having a twist angle of 5 to 30 degrees, and 3 is a margin portion on the outer periphery of the flute. And on the rake face on the tip side of the body 2, a single polycrystalline diamond chip 4 with cemented carbide each having a thickness of about 0.8 mm is placed on the back surface at two opposite locations on the same circumference. It is fixed so that it can be attached by brazing.

  As shown in FIG. 2 and FIG. 3, the polycrystalline diamond tip 4 with backing carbide has a flat thin plate shape, and a leading edge portion 6 is formed on the front side of the polycrystalline diamond tip 4 in the tool traveling direction. A finishing blade portion 7 is formed on the rear side. The polycrystalline diamond tip 4 has a first biting blade portion 9 (shaded portion in FIG. 2) extending along the chisel portion 8 having a tip angle of approximately 120 degrees in front of the leading blade portion 6 near the center. Have. The leading blade portion 6 and the finishing blade portion 7 are arranged as oblique blades along the margin portion 3 of the body 2 (see FIG. 4).

  The relief part (Nusumi part) 10 disposed between the leading blade part 6 and the finishing blade part 7 is substantially V-shaped (or substantially) including the second biting part 11 of the finishing blade part 7 in part. U-shaped). A second biting blade 11 (shaded portion in FIG. 2) is formed at the front end of the finishing blade 7. A step 13 corresponding to the front flank of the cutting tool is formed on the circumference of the body 2 so that the second biting blade portion 11 of the escape portion 10 functions well.

  The inclination angles α and β of the first and second biting blade portions 9 and 11 with respect to the rotation axis R are usually in the range of 10 to 60 °, and machining allowance, machining conditions, workpiece material, and necessary workpiece It is determined in consideration of quality.

  Further, in the direction of the rotational axis R from the outer end (so-called leading edge) 9a of the first biting portion 9 in the direction of the rotational axis R to the outer end (so-called finishing edge) 11a of the second biting portion 11 The length L1 needs to be 1 mm or more. This is to give the strength necessary for functioning as a leading blade and to form a substantially V-shaped (or U-shaped) Nusumi portion 10 therebetween. The length L1 is within 5 mm from the shape of the hole to be processed and the cost of the polycrystalline diamond tip.

  The finishing blade portion 7 has a slanting blade portion 7a extending from the outer end 11a of the second biting portion 11 to the rear in the rotation axis R by a length L3 (5 to 8 mm). Even when the second biting portion 11 of the finishing blade 7 is worn out and the cutting ability related to the work quality is lowered, the length of 5 to 8 mm is necessary so that the tool function can be restored by re-grinding. is there. Furthermore, as shown in FIG. 5, the center height H of the first biting portion 9 of the polycrystalline diamond tip 4 is appropriately 0 ± 0.2 mm, and ± 0.mm from the margin portion 3 of the polycrystalline diamond tip 4. It is arranged along the range of 2 mm. The same applies to the second biting portion 11.

  Here, (1) the body 2 has a flute portion 3a having a twist angle of 5 to 30 degrees, and (2) the polycrystalline diamond tip 4 is slanted along the margin portion 3 which is the outer edge of the flute portion 3a. (3) In the polycrystalline diamond tip 4, a leading blade portion 6 is integrally formed on the front side in the tool traveling direction, and a finishing blade portion 7 is integrally formed on the rear side. (4) The polycrystalline diamond tip 4 The center height H is 0 ± 0.2 mm. By satisfying the above conditions (1) to (4), it has a polycrystalline diamond tip in which the leading edge portion 6 and the finishing edge portion 7 are integrated. With regard to the rotary cutting tool 1 for multi-stage drilling, it becomes possible to perform roughing and finishing with a single tool, and further, the chip discharge efficiency is reduced by cutting the chips while cutting the chips. Can be improved when cutting It will be excluded as far as possible the influence of the chips, could have been in the roundness of the hole formed in the work better.

  The polycrystalline diamond tip 4 includes a leading edge portion 6 having a first biting portion 9, a substantially V-shaped or substantially U-shaped Nusumi portion 10, and a second located on the rear side of the Nusumi portion 10. The finishing blade portion 7 having the biting portion 11 is integrated. The inner end 11 b of the second biting part 11 is located on the inner side in the radial direction than the outer end 9 a of the first biting part 9. The outer end 11a of the second biting part 11 is positioned with a length L2 of 0.25 to 0.5 mm on the radially outer side from the outer end 9a of the first biting part 9. The length L1 in the rotation axis R direction from the outer end 9a of the first biting part 9 to the outer end 11a of the second biting part 11 is 1 to 5 mm. The finishing blade portion 7 has a portion extending 5 to 8 mm rearward from the outer end of the second biting portion in the rotation axis. With such a configuration, both the cutting ability as rough machining and the quality of finishing can be improved.

  It goes without saying that the present invention is not limited to the embodiment described above. For example, as shown in FIGS. 6 and 7, a rotary cutting tool 20 for drilling according to another embodiment is a reamer in which four polycrystalline diamond chips 4 are arranged on the tip of a body 21 in a cross shape. This reamer 20 is used for finishing when processing a hole opened by a drill or a cast hole. There are also multistage type, single diamond tip type, body tools other than carbide.

1 is a side view showing an embodiment of a rotary cutting tool for drilling according to the present invention. It is the schematic which expanded the principal part of FIG. It is a perspective view of a polycrystalline diamond tip applied to a rotary cutting tool for drilling according to the present invention. It is the enlarged view which looked at the rotary cutting tool from the preceding blade part and the finishing blade part side. It is the enlarged view which looked at the rotary cutting tool from the front end side. It is a side view which shows the rotary cutting tool for drilling which concerns on other embodiment. It is the enlarged view which looked at the rotary cutting tool from the front end side.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,20 ... Rotary cutting tool for drilling, 2 ... Body, 3 ... Margin part, 3a ... Flute part, 4 ... Polycrystalline diamond tip, 6 ... Leading blade part, 7 ... Finishing blade part, 7a ... Slope blade part, 9 ... 1st bite blade part, 10 ... Relief part (Nusumi part), 11 ... 2nd bite blade part, H ... Center height, R ... Rotation axis, L1 ... From the outer end of the 1st bite part Length in the rotation axis direction to the outer end of the second biting part, L2 ... Length in the radial direction from the outer end of the first biting part to the outer end of the second biting part, L3 ... Rotation The length of the beveled blade in the axial direction.

Claims (2)

In the rotary cutting tool for drilling with a polycrystalline diamond tip at the tip of the body,
The body has a flute portion with a twist angle of 5 to 30 °, and a leading blade portion and a finishing blade portion along a margin portion forming an outer edge of the flute portion having a twist angle with respect to a tool axis. A rotary cutting tool for drilling, characterized in that a polycrystalline diamond tip is disposed, and the center height of the polycrystalline diamond tip is 0 ± 0.2 mm. The polycrystalline diamond tip is
The leading blade portion having a first biting portion on the distal end side in the traveling direction of the tool, the substantially V-shaped or substantially U-shaped Nusumi portion located behind the leading blade portion in the tool traveling direction; The finishing blade part having the second bite part located on the rear side from the Nusumi part is integral,
The inner end of the second biting portion is located on the inner side in the radial direction from the outer end of the first biting portion, and the outer end of the second biting portion is the first biting portion. 0.25 to 0.5 mm located radially outward from the outer end of the part,
The length in the rotation axis direction from the outer end of the first biting portion to the outer end of the second biting portion is 1 to 5 mm,
2. The rotary cutting tool for drilling according to claim 1, wherein the finishing blade portion has a diagonal blade portion extending 5 to 8 mm rearward in the rotation axis from the outer end of the second biting portion.

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