JP2007276076A - Cemented carbide coating drill with oil hole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cemented carbide coating drill with an oil hole which is suitable for drilling the hole having 10 times of the diameter of the drill while discharging a small amount of mist from the oil hole opened to the tip of the blade edge passing through the inside of a drill land, and prevents the occurrence of hole expansion, the curvature of the hole, or undulation by suppressing the curvature or meandering of the hole without requiring a complicated manufacturing method. <P>SOLUTION: Two threads of chip discharge grooves 2 extending to a drill shank and a margin 3 having a pair of widths of 2.4 mm (40% of the diameter of the drill (it can be within 30 to 60%)) are formed on the outer peripheral surface of the drill body, and a main flank 13 and a sinning 4 continuing to a pair of main cutting blades 12 in the peripheral direction are formed at the tip. An inclined angle α of the sinning 4 is made to be 40° (it can be 40 to 50°) and the rear end 5 in the drill rotation direction is made to be overlapped (contact point 5) to the inclined surface of the sinning 4 to have two oil holes 6 at the land 8 along a drill helical angle. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention improves the accuracy of drilled holes in cemented carbide oil drilled coating drills that drill more than 10 times the diameter of the drill while discharging a small amount of mist from the oil hole that passes through the drill land and opens at the tip of the cutting edge. In addition, the present invention relates to a coated drill with an oil hole made of cemented carbide that can be easily manufactured.

Usually, drills used for drilling are provided with a certain margin in the land along the leading edge to reduce friction between the outer periphery of the drill and the inner wall of the processed hole. Processing is performed to reduce the resistance. For example, in Patent Document 1, the margin width of the drill is set to about 10 to 20% of the drill diameter in paragraph [0041], but is usually set to about 5 to 15% of the drill diameter. When drilling with a drill with a normal margin width of about 5 to 20% of the drill diameter, the drilled holes may be enlarged or the drilled holes may swell due to fluctuations in drill accuracy or vibration during drill installation. Occurs. The above problem is minor if the drilling depth is shallower than 3 times the drill diameter, but if the drilling depth exceeds 10 times the drill diameter, the drill groove length will inevitably become longer. The drill rigidity is lowered, and the above problem becomes remarkable.
JP 2003-300110 A [0041] JP-A-5-50313 [0010] Japanese Patent Laid-Open No. 2005-177891

  In order to improve the machining hole accuracy, in Patent Document 2, five spiral guides called tip margins are formed on the outer periphery of the land portion so as to extend over the entire circumferential direction. An axially recessed groove with a relief groove cut therein is disclosed. However, since this thread-shaped guide called a tip margin does not have a circumferential flank, it cannot be said to be a margin. The thread-shaped guide is defined as “a margin is not formed in the outer peripheral portion of the drill tip and the outer peripheral portion of the drill tip has the same diameter throughout the entire area”). In addition, such a thread-shaped guide is difficult to drill and regrind, and an edge is formed at the intersection of the leading edge and the tip margin. It was. Further, in Patent Document 3, the first margin adjacent to the land portion on the rear side in the drill rotation direction of the chip discharge groove, the second margin adjacent to the front side in the drill rotation direction of the chip discharge groove, and the first margin in the circumferential direction. A so-called triple margin drill is shown that forms one third margin located between one margin and the second margin, preferably the width of each margin is 3-4% of the drill diameter, In manufacturing, the second process for forming the margin becomes complicated, and chips generated by drilling between the second margin and the third margin may enter, and the inner wall of the processed hole There was a risk of scratching or breaking the drill.

  The object of the present invention is to suppress the bending of the hole and the meandering of the hole, which is suitable for drilling more than 10 times the diameter of the drill while discharging a minute amount of mist from the oil hole that opens through the drill land and opens at the tip of the blade tip. It is to provide a cemented carbide oil drilled coating drill that does not generate hole enlargement, hole bending or waviness without requiring a complicated manufacturing method.

  For this reason, the present invention provides a cemented drill with oil hole made of cemented carbide that performs deep hole machining more than 10 times the diameter of the drill while discharging a minute amount of mist from the oil hole. A main flank and a thinning are formed on the pair of main cutting edges in the circumferential direction, the margin width is in the range of 30% to 60% of the drill diameter, and the inclination angle of the thinning is 40 to 50 °. The above-mentioned problem was solved by providing a cemented drill with oil hole made of cemented carbide, characterized in that the rear end of the margin of the drill in the drill rotating direction is on the thinning inclined surface.

With such a configuration, in the present invention, in a coated drill with a hard hole made of a cemented carbide alloy that performs deep hole machining of 10 times or more the drill diameter while discharging a minute amount of mist from the oil hole, the margin width is 30% to 60% of the drill diameter. In this range, guideability is improved and bending and waviness of the drilled hole is suppressed to improve the precision of the drilled hole, and the tilt angle of the thinning is set to 40 to 50 °, and the rear end of the pair of margins in the drill rotation direction is thinned. Generally, the clearance angle of the drill is about 10 °, but the thinning inclination angle is as large as 40 to 50 °. A coating drill with oil holes made of cemented carbide that contributes to the stability of guideability when drill biting or drilling is achieved. Further, the second taking process for forming the margin is the same as that of a normal drill, and a cemented drill with an oil hole made of cemented carbide does not require a complicated manufacturing process as in the prior art.
In other words, when the margin width is 20% or less of the drill diameter, the undulation of the drilled hole occurs. When the margin width exceeds 70% of the drill diameter, the contact range between the inner wall of the drilled hole and the drill margin increases, and torque resistance during machining increases. Since it increases rapidly, the margin width is specified as 30% to 60% with respect to the drill diameter. Also, when the trailing edge of the margin drill rotation direction does not cover the thinning slant surface, the contact point between the trailing edge of the margin drill rotation direction and the flank surface is short in the drill groove length direction, and the guide performance when drill biting is reduced. Since it causes caulking hole enlargement and hole waviness, it is defined that the rear end of the margin in the drill rotation direction is on the thinning inclined surface.

  In addition, since the margin width is larger than that of a normal drill, the inner wall of the machining hole and the margin are worn more easily and wear tends to proceed. Preferably, the coating coating of the cemented carbide oil-coated coating drill is preferably at least from the tip of the drill. Within a range of 2 mm or more, 0.5 to 5 of one or more layers of carbides, nitrides, oxides or borides of Group 4a, 5a, 6a transition metals and Group 3b, 4b elements of Periodic Table 3 Coating with μm suppresses abrasion and abrasion at the margin, and drills and undulates when drilling more than 10 times the drill diameter while discharging a small amount of mist from the oil hole along the drill twist groove. Improved hole accuracy

  The best mode for carrying out the present invention will be described with reference to FIG. Fig. 1 shows a coated drill with a 6mm diameter, a groove length of 150mm, and a total length of 200mm, which is suitable for drilling more than 10 times the diameter of a drill while discharging a minute amount of mist from an oil hole according to an embodiment of the present invention. (A) is a side view, (b) is a left end view of (a), and (c) is an enlarged view of a main part in which the tip portion of the side view of (a) is enlarged. In the embodiment of the present invention, a coating drill 1 with a cemented carbide oil hole having a diameter of 6 mm, a groove length of 159 mm, and a total length of 200 mm suitable for drilling more than 10 times the diameter of the drill while discharging a minute amount of mist from the oil hole 6 is as follows. A pair of 2.4mm on the outer peripheral surface of the drill body and the two chip discharge grooves 2 extending to the drill handle and the outer peripheral land 8 (40% of drill diameter (may be in the range of 30% to 60%)) A margin 3 having a width of 1 mm is formed, a main flank 13 and a thinning 4 are formed at the tip of the pair of main cutting edges 12 in the circumferential direction, and an inclination angle α of the thinning 4 is 40 ° (40 to 50 °). As an alternative, the two oil holes 6 along the drill twist angle are formed so that the rear end 5 in the drill rotation direction of the margin covers the thinning inclined surface 4 (contact point 5) and opens to the main flank 13 of the land portion 8. Have

  As shown in FIG. 1 (c), the coating coating of the cemented carbide drill hole 1 made of cemented carbide is in the range of 3 mm (at least 2 mm or more) from the drill tip 7, and the 4a, 5a, 6a group transition of the periodic table. The metal and carbides, nitrides, oxides or borides of Group 3b and 4b elements of the periodic table were coated with 0.5 to 5 μm in one or more layers.

  Fig. 2 shows a drill drill with a cemented carbide oil hole with the shape shown in Fig. 1, with a margin width set between 20% and 70% of the drill diameter, and the hole depth in the work material S50C (200 HB). Drilling hole of 60mm (10 times the diameter of drill), cutting speed 80m / min, feed rate 764mm / min, machining hole accuracy measurement chart when using a trace amount of mist oil and vertical axis for horizontal time (seconds) The graph which shows spindle power (V) is shown, respectively. When the margin width of (a) is 20% of the drill diameter, the spindle power during machining is stable, but undulation occurs in the drilled hole. When the margin width of (f) is 70% of the drill diameter, The marginal abrasion increases and the spindle power increases significantly. When the margin widths (b) to (e) are between 30% and 60% of the drill diameter, the spindle power during machining is stable and the hole accuracy is high. Was also good.

FIG. 3 shows a coated drill with oil holes made of cemented carbide with the margin shown in FIG. 5 having a margin width of 30% and 60% of the drill diameter and the rear end of the margin in the drill rotation direction on the flank. A machining hole accuracy measurement chart when a drilling test is performed under the same cutting conditions as in Example 1 and a graph showing a vertical axis principal axis power (V) with respect to the horizontal axis time (seconds) are shown.
The coated drill with a cemented carbide oil hole having the shape shown in FIG. 5 is similar to the coated drill with a cemented carbide oil hole of the present invention, in which (a) margin width is 30% of the drill diameter and (b) margin width. The drill is such that the rear end 15 of the margin drill rotation direction does not touch the thinning inclined surface 4 but covers the flank 13 and the second catching surface 10 and the margin 3 The contact 15 between the rear end of the drill in the drill direction and the flank face is short in the length direction of the drill groove, and the guideability when the drill bites becomes unstable, and some undulation occurs on the inlet side.

  Coated drill with φ6 cemented carbide oil hole with the shape shown in Fig. 1 of the present invention product and φ6 cemented carbide oil hole with margin width of 0.4mm (7% of drill diameter) with the shape shown in Fig. 6 of the conventional product With a coated drill, a drilling test was performed on the work material SCM440 (310HB) with a hole depth of 60 mm, cutting speed of 50 m / min, feed speed of 470 mm / min, and mist oil. FIG. 4A shows a machining hole accuracy measurement chart and a graph showing the vertical axis spindle power (V) with respect to the horizontal axis time (seconds), and FIG. 4B shows a wear amount comparison graph after machining 800 holes. Conventional drills have stable spindle power, but undulations occur with drilled hole accuracy. The drill of the product of the present invention had good machining hole accuracy and spindle power. In comparison with the amount of wear after processing 800 holes, the amount of wear of the present invention product is slight, whereas in the conventional product, undulation of the processed hole has occurred, and the wear of the corner portion in particular has increased.

[Effect of the embodiment of the present invention] In the embodiment of the present invention, in a coated drill with a hard hole made of cemented carbide that performs deep hole machining of 10 times or more of the drill diameter while discharging a minute amount of mist from the oil hole, the margin width is increased. By defining it within the range of 30% to 60% of the drill diameter, it improves guideability and suppresses bending and waviness of the drilled hole to improve the precision of the drilled hole, and a pair of margins with a thinning inclination angle of 40 to 50 ° By making the rear end of the drill rotation direction on the thinning inclined surface, the clearance angle of the drill is generally about 10 °, whereas the thinning inclination angle is as large as 40 to 50 °, so after the margin drill rotation direction Provided a coated drill with cemented carbide oil holes that contributes to the stability of the guide when drilling or penetrating. It became something to do. Further, the second taking process for forming the margin is the same as that of a normal drill, and a cemented drill with an oil hole made of cemented carbide does not require a complicated manufacturing process as in the prior art.
In addition, since the margin width is larger than that of a normal drill, the inner wall of the machining hole and the margin are worn more easily and wear tends to proceed. Preferably, the coating coating of the cemented carbide oil-coated coating drill is preferably at least from the tip of the drill. Within a range of 2 mm or more, 0.5 to 5 of one or more layers of carbides, nitrides, oxides or borides of Group 4a, 5a, 6a transition metals and Group 3b, 4b elements of Periodic Table 3 Coating with μm suppresses abrasion and abrasion at the margin, and drills and undulates when drilling more than 10 times the drill diameter while discharging a small amount of mist from the oil hole along the drill twist groove. Improved hole accuracy

An embodiment of the present invention shows a coated drill with a cemented carbide oil hole with a diameter of 6 mm, a groove length of 159 mm, and a total length of 200 mm suitable for drilling 10 times the diameter of the drill while discharging a minute amount of mist from the oil hole, (A) is a side view, (b) is a left end view of (a), and (c) is an enlarged view of a main part in which a tip portion of the side view of (a) is enlarged. This is a coated drill with oil holes made of cemented carbide shown in Fig. 1, with a margin width set to 20% to 70% of the drill diameter, and a hole depth of 60 mm (drill diameter) on the work material S50C (200 HB). Vertical axis spindle power (V) with respect to drilling hole accuracy measurement chart and horizontal axis time (seconds) when testing with drilling speed of 10m), cutting speed 80m / min, feed rate 764mm / min, using trace amount mist oil ) Are shown respectively. 5 is a cemented carbide oil drilled coating drill with a margin width of 30% and 60% of the drill diameter and the rear end of the margin in the drill rotation direction on the flank. A machining hole accuracy measurement chart when performing a drilling test under the same cutting conditions and a graph showing the vertical axis main axis power (V) with respect to the horizontal axis time (seconds) are shown. A drilling test was conducted between the coated drill with oil hole made of φ6 cemented carbide shown in FIG. 1 and the conventional drill with the shape shown in FIG. 6 having a margin width of 0.4 mm. (A) is a graph showing the machining accuracy measurement chart and the vertical axis power (V) with respect to the horizontal axis time (seconds), and (b) is a wear amount comparison graph after processing 800 holes. As with the coated drill with a cemented carbide oil hole of the present invention, (a) has a margin width of 30% of the drill diameter, and (b) has a margin width of 60% of the drill diameter. A coated drill with an oil hole made of cemented carbide, which is a prototype in which the end 15 does not extend on the thinning inclined surface 4 but on the flank 16, (a) shows a side view of the drill, and (b) shows (a ) Is a left end view, and FIG. 9C is an enlarged view of a main part in which a tip portion of the side view of FIG. The margin width of the conventional product is 0.4mm (7% of the drill diameter). This shows a coated drill with oil holes made of cemented carbide, (a) is a side view of the drill, and (b) is a left end view of (a).

Explanation of symbols

1: Coated drill with oil hole made of cemented carbide, 2: Chip discharge groove, 3: Margin 4: Thinning, 5: Margin rear end (contact with thinning inclined surface), 6: Oil hole 7: Drill tip, 8: Outer peripheral land part, 15: Second picking part
12: Main cutting edge, 13: Main flank surface, 10: Recessed part, α: Thinning inclination angle

Claims (2)

  In a cemented carbide oil drilled coating drill that drills more than 10 times the diameter of the drill while discharging a small amount of mist from the oil hole, a pair of margins are formed on the outer peripheral land, and a pair of main cutting edges are formed at the tip. A main flank and a thinning are formed in the circumferential direction, the margin width is in the range of 30% to 60% of the drill diameter, and the inclination angle of the thinning is 40 to 50 °, the drill rotation direction of the pair of margins A coated drill with a cemented carbide oil hole, characterized in that the rear end is applied to a thinning inclined surface. The coating of the cemented carbide oil hole coated drill is at least 2 mm or more from the drill tip, and carbides of Group 4a, 5a, 6a transition metals and Group 3b, 4b elements of the Periodic Table, The drill according to claim 1, wherein one or two or more layers of nitride, oxide or boride are coated with 0.5 to 5 µm.

Images