JPH0437689Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to rotary cutting tools such as end mills used in milling machines and the like, and particularly relates to improvements in rotary cutting tools capable of supplying compressed air. [Problems to be solved by conventional techniques and ideas] When milling is performed with a rotary cutting tool such as an end mill that has a straight shank, the cutting edge may chip or break due to the biting of generated chips. It is often experienced that the machine becomes unusable or damages the cutting surface of the workpiece. Therefore, in order to eliminate the above-mentioned problems caused by chips, a method has been adopted in which compressed air or the like is ejected from the outside of the rotating tool onto the cutting edge using a nozzle. However, in this method, the nozzle position relative to the cutting edge is fixed, so in processing where the cutting direction changes, such as contouring processing using a machining center, the nozzle position will not be optimal and chip removal cannot be performed stably. For this reason, it has been proposed, for example, as in Japanese Patent Publication No. 61-44608, to inject pressurized fluid from inside the end mill body in a direction substantially perpendicular to the cutting blade. In this case, generated chips can be reliably removed from the cutting edge regardless of changes in the cutting direction. However, while it may be fine for simple surface milling, when machining holes, counterbores, or uneven shapes in several parts, compressed fluid is injected in a direction almost perpendicular to the cutting edge. , the generated chips are mainly flown in the direction perpendicular to the cutting edge. That is, the chips are blown away along the cutting bottom surface, and are therefore deposited in the holes, counterbore portions, and unevenly shaped recesses and corner portions on the cutting bottom surface.
Then, when digging down and cutting that area, there was a problem that the accumulated chips would be caught. It is an object of the present invention to solve the above-mentioned problems and provide a rotary cutting tool with fewer troubles caused by chips. [Means for Solving the Problems] In order to achieve the above object, the present invention has the following constituent requirements. That is, the rotary cutting tool of the present invention includes a tool body having a cylindrical straight shank portion and a cutting edge portion having a cutting edge at the other end, a supply hole extending in the longitudinal direction of the tool body, and a cutting edge portion having a cutting edge at the other end. A rotary cutting tool having an injection hole that communicates with a supply hole, opens into a chip discharge groove of the cutting edge, and blows out compressed air to the cutting edge, the opening direction of the injection hole being aligned with the tool axis. It is characterized in that it is provided inclined upward on the rear end side of the cutting blade with respect to the direction perpendicular to the center. [Function] According to the present invention, the injection hole that connects to the supply hole inside the tool body and opens into the chip discharge groove opens at an angle toward the rear end of the cutting blade with respect to the direction perpendicular to the axis of the tool body. Therefore, the generated chips are blown diagonally upward from the direction of the cutting bottom surface, and it is possible to significantly reduce the accumulation of chips in the holes and counterbore portions on the bottom surface after cutting. [Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a throw-away end mill according to the present invention, in which a main body 1 consists of a straight shank portion 2 and a cutting blade portion 3 to which a throw-away tip 6 is attached. Two chip discharge grooves 9 are formed at the tip of the cutting edge 3, and a throw-away tip 6 is removably fixed to a tip seat in the grooves by a set screw 7. An injection hole 5 is communicated with the distal end side of the supply hole 4 extending near the center in the longitudinal direction of the main body 1, and is open to each chip discharge groove 9. Incidentally, the injection hole angle θ indicating the opening direction of the injection hole at this time is an upward direction inclined toward the rear end 10 side of the cutting blade with respect to a direction perpendicular to the axis of the main body. Next, a specific experimental example of the present invention will be explained.
Using the indexable end mill according to the present invention shown in Fig. 1, a 20 mm diameter drill is applied to the surface of a 150 mm long workpiece (mechanical structural carbon steel S50C, hardness: Hs32) shown in Fig. 2. Grooving of the portion including the hole was repeated twice at a cutting depth of 6 mm under the conditions shown in Table 1 below, and the state of chip discharge was examined. For comparison, a similar test was also conducted on a comparative product in which the injection hole angle θ=0° and the other shapes were the same as the inventive product.

【table】

[Effect of idea]

In this invention, the injection hole that opens into the chip evacuation groove is tilted upward on the rear end of the cutting blade with respect to the direction perpendicular to the axis of the main body, so that the generated chips can be thrown upward against the bottom surface of the cutter. As a result, even when machining a cut surface with a hole or counterbore, and then digging down the area further, the chances of chips machined in the previous process getting into the holes and accumulating are significantly reduced, reducing chip entrapment. It is possible to provide a rotary cutting tool that causes fewer troubles due to chips such as.

[Brief explanation of the drawing]

Figure 1 is a front view of an indexable end mill according to an embodiment of the present invention, Figure 2 is a diagram showing the shape of the workpiece used in the cutting test, Figure 2a is the front view, and Figure 2b is the front view. 3 is a schematic diagram showing the state of chip discharge at the BB-B cross section in FIG. 2 during a cutting test with the product of the present invention, and FIG.
It is a schematic diagram showing the chip discharge situation by a comparison product similarly to the figure. 1... Tool body, 2... Straight shank part, 3... Cutting blade part, 4... Supply hole, 5... Injection hole, 8... Cutting blade, 9... Chip discharge groove, 10... Cutting Blade rear end, 11... Direction perpendicular to the axis of the main body, θ... Injection hole angle.

Claims (1)

[Scope of utility model registration request] a tool body having a cylindrical straight shank portion and a cutting edge portion having a cutting edge at the other end; a supply hole extending longitudinally within the tool body; and a supply hole communicating with the supply hole and the cutting blade. Opens in the chip discharge groove of the part,
A rotary cutting tool having an injection hole for ejecting compressed air to the cutting blade, wherein the opening direction of the injection hole is inclined upward on a rear end side of the cutting blade with respect to a direction perpendicular to the axis of the tool body. A rotary cutting tool comprising: