JP4937368B2 - Rotary cutting tool - Google Patents

Description

  The present invention relates to a rotary cutting tool.

  As a rotary cutting tool such as a router used for processing a printed wiring board or an end mill used for processing a metal material, for example, as disclosed in Patent Document 1, an outer peripheral cutting edge is divided on the outer peripheral flank of the tool. Some have a chip breaker.

JP 2008-114308 A

  By the way, although the said chip breaker is provided in order to improve chip discharge | emission property, in conventional rotary cutting tools, it cannot be said that sufficient chip discharge | emission property is obtained, and further chip discharge | emission is obtained. Currently, there is a demand for improved performance.

  In the present invention, as a result of various investigations by the inventors in view of the above-described situation, chips generated by the chip breaker depend on the positional relationship between the chip breaker and the outer peripheral cutting edge adjacent to the rear side in the tool rotation direction of the chip breaker. The present invention has been completed and found that the effect of improving the discharge efficiency is greatly different, and provides a rotary cutting tool excellent in practicality that has an extremely large effect of improving chip discharge by a chip breaker.

  The gist of the present invention will be described with reference to the accompanying drawings.

  A plurality of spiral chip discharge grooves 2 are formed on the outer periphery of the tool main body 1 from the tool front end to the base end side. The rake face of the chip discharge groove 2 and the outer peripheral surface of the tool main body 1 or the tool main body 1 An outer peripheral cutting edge 3 is formed at an intersection ridge line portion with an outer peripheral flank formed on the outer periphery, and a plurality of chip breakers are provided on the outer peripheral surface of the tool body 1 or the outer peripheral flank so as to divide the outer peripheral cutting edge 3. 4 is provided, and the rotation locus of the outer peripheral cutting edge 3 adjacent to the part of the rotation locus of the chip breaker 4 on the rear side in the tool rotation direction is 40% or more. The present invention relates to a rotary cutting tool that is configured to overlap at a ratio.

  Further, in the rotary cutting tool according to claim 1, the overlapping ratio of the rotation trajectory of the chip breaker 4 and the rotation trajectory of the outer peripheral cutting edge 3 is the chip breaker 4 with respect to the length of the chip breaker 4 in the tool rotation axis direction. It is the ratio of the length of the said outer peripheral cutting edge 3 which overlaps with this rotation locus | trajectory, It concerns on the rotary cutting tool characterized by the above-mentioned.

  Moreover, in the rotary cutting tool according to any one of claims 1 and 2, the overlapping ratio of the rotation locus of the chip breaker 4 and the rotation locus of the outer peripheral cutting edge 3 is set to 40% or more and 90% or less. The present invention relates to a rotary cutting tool.

  Further, in the rotary cutting tool according to any one of claims 1 and 2, the overlapping ratio of the rotation locus of the chip breaker 4 and the rotation locus of the outer peripheral cutting edge 3 is set to 50% or more and 90% or less. The present invention relates to a rotary cutting tool.

  Moreover, the rotary cutting tool of any one of Claims 1-4 WHEREIN: The ratio of the length of the outer peripheral cutting edge 3 with respect to the length of the said chip breaker 4 is set to 40% or more and 120% or less. The present invention relates to a featured rotary cutting tool.

  Moreover, the rotary cutting tool of any one of Claims 1-4 WHEREIN: The ratio of the length of the outer periphery cutting edge 3 with respect to the length of the said chip breaker 4 is set to 50% or more and 120% or less. The present invention relates to a featured rotary cutting tool.

  Further, in the rotary cutting tool according to any one of claims 1 to 6, the rotational trajectory of the outer peripheral cutting edge 3 is configured to overlap with a tool proximal end portion of the rotational trajectory of the chip breaker 4. It concerns on the rotary cutting tool characterized by these.

  Moreover, the rotary cutting tool of any one of Claims 1-7 WHEREIN: This tool concerns on the rotary cutting tool characterized by being 1.5 mm or less in diameter.

  Since this invention was comprised as mentioned above, it becomes a rotary cutting tool excellent in practicality in which the chip | tip chipbreaker has the extremely large improvement effect of chip discharge | emission property.

It is a schematic explanatory side view of the principal part of a present Example. It is a schematic explanatory drawing of the principal part of a present Example. It is a schematic explanatory drawing of the principal part of a present Example. It is an expansion schematic explanatory drawing of the principal part of a present Example. It is a schematic explanatory side view of the principal part of a prior art example. It is a table | surface which shows the experimental condition and experimental result of an experiment example. It is the graph which compared the chip | tip discharge | emission lifetime of an Example and a comparative example. It is the graph which compared the chip | tip discharge | emission lifetime of an Example and a comparative example. It is the photograph which compared the processing result by an Example and a comparative example.

  An embodiment of the present invention which is considered to be suitable will be briefly described with reference to the drawings showing the operation of the present invention.

  When the outer peripheral cutting edge 3 of the rotating tool body 1 is brought into contact with the workpiece and the workpiece is cut, the chips are moved in a predetermined direction (upward or downward) by the chip discharge groove 2, and The part moves via the chip breaker 4 to the adjacent chip discharge groove 2 on the rear side in the tool rotation direction.

  At this time, when the rotation locus of the outer peripheral cutting edge 3 adjacent to the rear side in the tool rotation direction of the chip breaker 4 overlaps a part of the rotation locus of the chip breaker 4 at a rate of 40% or more, as shown in FIG. In addition, the chips that have passed through the chip breaker 4 easily come into contact (collision) with the outer peripheral cutting edge 3 (the rake face), and can be forcibly moved in a predetermined direction by contact with the outer peripheral cutting edge 3.

  Accordingly, the chips not only move along the chip discharge grooves 2 but also receive an upward or downward force by contact with the outer peripheral cutting edge 3 adjacent to the rear side in the tool rotation direction of the chip breaker 4. The guide is forced to move in a predetermined direction.

  Therefore, the chip discharging performance is greatly improved, and the breakage resistance, the diameter reduction amount and the collapse amount are improved accordingly. In other words, the chip is discharged well, so that the welding of the chip to the rake face of the workpiece or the tool is suppressed, and the increase in the cutting resistance and the decrease in the heat dissipation (the increase in the cutting temperature) due to this welding. The accompanying tool breakage can be prevented and the amount of diameter reduction and the amount of collapse can be suppressed.

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

  In the present embodiment, a plurality of spiral chip discharge grooves 2 extending from the tool tip to the base end side are formed on the outer periphery of the tool body 1, and the rake face of the chip discharge groove 2 and the outer peripheral surface of the tool body 1 or An outer peripheral cutting edge 3 is formed at an intersecting ridge line portion with an outer peripheral flank formed on the outer periphery of the tool main body 1, and the outer peripheral cutting edge 3 is divided in the extending direction of the outer peripheral cutting edge 3. 1 is a rotary cutting tool in which a plurality of chip breakers 4 are provided on the outer peripheral surface or the outer peripheral flank surface, and as shown in FIGS. The rotation trajectory of the outer peripheral cutting edge 3 adjacent to the rear side in the tool rotation direction of the chip breaker 4 is configured to overlap at a rate of 40% or more.

  Specifically, the present embodiment has a bottom blade at the distal end and a shank portion connected to the tool mounting portion of the printed wiring board outer shape processing machine at the base end portion. The present invention is applied to a router that is attached to a printed wiring board or the like that performs cutting processing such as long hole processing and outer shape processing. ), The workpiece is cut, and chips are discharged from above the tool (base end side).

  Further, the detailed configuration of each part is the same as the basic configuration of a router that is generally widely used. That is, it has a configuration of four or more blades provided with four outer peripheral cutting edges 3 (six blades in this embodiment), each outer peripheral cutting edge 3 is set to a right twist, and each outer peripheral cutting edge is also set. 3 is equally divided in the circumferential direction, and the chip breakers 4 are arranged at an equal pitch along the spiral direction of the outer peripheral cutting edge 3. Moreover, it is preferable to set the twist angle of the outer peripheral cutting edge 3 in the range of 20 ° to 40 °. In the present embodiment, each is set to 30 °. This is because if the angle is less than 20 °, the chip discharging property deteriorates, and if it exceeds 40 °, burrs are easily generated and the breakage life is shortened.

  Further, in the present embodiment (embodiment 1 described later), the chip breakers 4 are arranged side by side along the left twist direction so that two strips are provided, and the twist angle is set to 64 °. In other examples and comparative examples, the twist angle of the chip breaker 4 is appropriately set according to the ratio of the length of the outer peripheral cutting edge 3 that overlaps the rotation trajectory of the chip breaker 4. The twist direction (parallel arrangement direction) and cross-sectional shape of the chip breaker 4 are not particularly limited, and various configurations can be adopted.

  In addition, although the present Example demonstrates the example which applied this invention to the router, you may apply not only to a router but to other rotary cutting tools, such as an end mill. Moreover, it is good also as other structures, such as the structure which rotates the tool main body 1 in the left-handed screw direction, or performs the cutting | discharging of a chip from the tool lower part.

  Further, when the rotation trace of the outer peripheral cutting edge 3 adjacent to the part of the rotation breaker 4 adjacent to the rear side in the tool rotation direction of the chip breaker 4 is configured to overlap, the rotation trace of the outer peripheral cutting edge 3 is: As shown in FIG. 2, the tool breaker 4 may overlap the tool base end portion of the rotation locus of the chip breaker 4, or overlap the tool tip end portion of the tip breaker 4 rotation locus as shown in FIG. 3. You may comprise as follows.

  In the present embodiment, as shown in FIG. 2, the rotation locus of the outer peripheral cutting edge 3 is configured to overlap with the tool proximal end portion of the rotation locus of the chip breaker 4. This is because, when the chip discharge groove 2 is right-handed, if machining is performed while rotating the downward tool body 1 in the right-hand screw direction, the chips are easily discharged upward (toward the tool base side). This is because it is more effective for the rake face to be on the tool proximal side (upper side) in order to bring a large amount of chips into contact (impact) with the rake face of the tool.

  In the present embodiment, the overlapping ratio of the rotation locus of the chip breaker 4 and the rotation locus of the outer peripheral cutting edge 3 is set to 40% to 90%, particularly preferably 50% to 90%. This is because when the amount is less than 50%, the area where the chips come into contact is reduced, and the discharge amount and the discharge force to the tool base end side are reduced accordingly, and when the amount exceeds 90%, the chips are in contact with each other. This is because the area to be processed becomes too large, and welding is facilitated accordingly, and cutting resistance increases.

  In the present embodiment, the overlapping ratio of the rotation trajectory of the chip breaker 4 and the rotation trajectory of the outer peripheral cutting edge 3 is the outer circumference overlapping the rotation trajectory of the chip breaker 4 with respect to the length of the chip breaker 4 in the tool rotation axis direction. It means the ratio of the length of the cutting edge 3. Specifically, as illustrated in FIG. 4, the length of the portion where the chip breaker 4 and the outer peripheral cutting edge 3 overlap (the length P of the portion where the cutting blades overlap is subtracted from the length B of the outer peripheral cutting blade 3. Value (B−P)) divided by the length C of the chip breaker (that is, (B−P) / C). In FIG. 4, the symbol A is the pitch of the outer peripheral cutting edge 3.

  Further, the ratio of the length of the outer peripheral cutting edge 3 to the length of the chip breaker 4 is set to 40% to 120%, particularly preferably 50% to 120%. This is because when the amount is less than 50%, the area where the chips come into contact is reduced, and the discharge amount and discharge force to the tool base end side are reduced accordingly, and when the amount exceeds 120%, the peripheral cutting edge 3 This is because the overlapping ratio increases too much and the cutting resistance increases, and the length of the chip breaker 4 becomes too short so that the chips are not easily discharged from the chip discharge groove 2.

  The tool diameter is set to 1.5 mm or less. This is because a tool having a tool diameter of 1.5 mm or less, particularly 0.8 mm or less, is used at a very high cutting speed (peripheral speed), and thus the chip discharge improvement effect by the above-described configuration appears very remarkably.

  Since the present embodiment is configured as described above, when the outer peripheral cutting edge 3 of the rotating tool body 1 is brought into contact with the workpiece and the workpiece is cut, the chips are moved upward by the chip discharge groove 2. While being moved, a part moves to the adjacent chip discharge groove 2 on the rear side in the tool rotation direction via the chip breaker 4.

  At this time, when the rotation trajectory of the outer peripheral cutting edge 3 adjacent to the rear side in the tool rotation direction of the chip breaker 4 overlaps a part of the rotation trajectory of the chip breaker 4 at a rate of 40% to 90%, FIG. As shown in the figure, the chips that have passed through the chip breaker 4 easily come into contact (collision) with the outer peripheral cutting edge 3 (the rake face), and are also forced upward by contact (collision) with the outer peripheral cutting edge 3. It is moved, and the movement to the adjacent chip discharge groove 2 and the contact with the outer peripheral cutting edge 3 are repeated, and it is discharged in a stepped manner as shown by the arrows in FIG.

  Therefore, the chips not only move along the chip discharge groove 2 but also in a predetermined direction while receiving an upward force by contact with the outer peripheral cutting edge 3 adjacent to the rear side in the tool rotation direction of the chip breaker 4. It will be forced to move the guide.

  In this respect, for example, in the tool as shown in FIG. 5 in which the rotation trajectory of the outer peripheral cutting edge 3 ′ of the tool body 1 ′ adjacent to the rear side in the tool rotation direction of the chip breaker 4 ′ is less than 40%, adjacent chips After moving to the discharge groove 2 ′, contact with the outer peripheral cutting edge 3 ′ does not occur, and it passes through the chip breaker 4 ′ as shown by an arrow in FIG. There is no forced upward movement.

  Therefore, the chip discharging performance is greatly improved, and the breakage resistance, the diameter reduction amount and the collapse amount are improved accordingly. In other words, the chip is discharged well, so that the welding of the chip to the rake face of the workpiece or the tool is suppressed, and the increase in the cutting resistance and the decrease in the heat dissipation (the increase in the cutting temperature) due to this welding. The accompanying tool breakage can be prevented and the amount of diameter reduction and the amount of collapse can be suppressed.

  As described above, the present embodiment is a rotary cutting tool with excellent practicality in which the chip dischargeability improving effect by the chip breaker is extremely large.

  An experimental example supporting the effect of the present embodiment will be described.

  FIG. 6 shows an evaluation of the tool chip discharge life by variously changing the pitch A of the outer peripheral cutting edge, the length B of the outer peripheral cutting edge, the length C of the chip breaker, and the length P of the portion where the cutting edges overlap each other. It is a table | surface which shows an experimental condition and an experimental result.

  FIG. 6 shows that the ratio (BP) / C where the rotation trace of the chip breaker and the rotation trace of the outer peripheral cutting edge overlap is less than 40% or exceeds 90%, and the length of the outer peripheral cutting edge with respect to the length of the chip breaker. Compared to Comparative Examples 1 to 5 where the ratio B / C is less than 40% or more than 120%, in Examples 1 to 13 that satisfy the conditions of the present example, the chip discharge life is good. It can be confirmed.

  Specifically, the chip discharge life is a slit process in which a slit having a length of 0.15 m as shown in FIG. 9 is repeatedly processed on a printed wiring board under the same conditions (predetermined rotation speed and predetermined feed rate). 7 and 8, the processing distance until the chip clogging rate reaches 50% (the processing distance until the slit where 50% of the slit length is clogged with chips appears, chip discharge This was done by comparing the life). 9A shows a substrate processed with the tool according to Example 1, and FIG. 9B shows a substrate processed with the tool according to Comparative Example 3.

  For example, from FIG. 7, the chip discharge lifetimes of Comparative Examples 1, 2, and 3 are 8.15 m, 5.43 m, and 3.58 m, respectively, while the chip discharge lifetime of Example 1 is 11.17 m. It can be confirmed that the length is dramatically increased. Similarly, from FIG. 8, the chip discharge life of Comparative Examples 4 and 5 is 24.00 m and 4.63 m, respectively, whereas the chip discharge life of Example 7 is dramatically increased to 31.85 m. I can confirm that.

  From the above, the overlapping ratio (BP) / C of the rotation locus of the chip breaker and the rotation locus of the outer peripheral cutting edge is set to 40% or more and 90% or less, and the ratio of the length of the outer peripheral cutting edge to the length of the chip breaker B / By setting C to 40% or more and 120% or less, the positional relationship between the chip breaker and the outer peripheral cutting edge adjacent to the rear side in the tool rotation direction of the chip breaker is optimized, and the chip discharge performance is greatly improved. Along with this, it was confirmed that the chip discharge life was prolonged.

1 Tool body 2 Chip discharge groove 3 Outer peripheral cutting edge 4 Chip breaker

Claims (8)

  A plurality of spiral chip discharge grooves are formed on the outer periphery of the tool main body from the tip of the tool toward the base end, and formed on the rake face of the chip discharge groove and the outer peripheral surface of the tool main body or the outer periphery of the tool main body. A rotary cutting tool in which an outer peripheral cutting edge is formed at an intersecting ridge line portion with an outer peripheral flank, and a plurality of chip breakers are provided on the outer peripheral surface of the tool body or the outer peripheral flank so as to divide the outer peripheral cutting edge. And it is comprised so that the rotation locus of the above-mentioned peripheral cutting edge which adjoins the rotation direction of the tool breaker of this tip breaker in the part of the rotation locus of the above-mentioned chip breaker may overlap with a part of 40% or more. Rotating cutting tool.   2. The rotary cutting tool according to claim 1, wherein the overlapping ratio of the rotation locus of the chip breaker and the rotation locus of the outer peripheral cutting edge overlaps the rotation locus of the chip breaker with respect to the length of the chip breaker in the tool rotation axis direction. A rotary cutting tool characterized in that it is a ratio of the length of the outer peripheral cutting edge.   The rotary cutting tool according to any one of claims 1 and 2, wherein the overlapping ratio of the rotation trace of the chip breaker and the rotation trace of the outer peripheral cutting edge is set to 40% or more and 90% or less. Rotating cutting tool.   The rotary cutting tool according to any one of claims 1 and 2, wherein the overlapping ratio of the rotation trace of the chip breaker and the rotation trace of the outer peripheral cutting edge is set to 50% or more and 90% or less. Rotating cutting tool.   The rotary cutting tool according to any one of claims 1 to 4, wherein a ratio of a length of the outer peripheral cutting edge to a length of the chip breaker is set to 40% or more and 120% or less. Cutting tools.   The rotary cutting tool according to any one of claims 1 to 4, wherein the ratio of the length of the outer peripheral cutting edge to the length of the chip breaker is set to 50% or more and 120% or less. Cutting tools.   The rotary cutting tool according to any one of claims 1 to 6, wherein the rotation trajectory of the outer peripheral cutting edge is configured to overlap with a tool proximal end portion of the rotation trajectory of the chip breaker. Rotary cutting tool.   The rotary cutting tool according to any one of claims 1 to 7, wherein the tool has a diameter of 1.5 mm or less.