JPS628975Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an improvement of a two-flute end mill that can perform axial cutting and horizontal cutting with a single tool.

Prior Art In a conventional two-flute end mill, the main end cutting edge and the auxiliary end cutting edge are on the same level with respect to the axial direction of the tool, and both of the cutting edges are formed in a straight line.

Problems that the invention aims to solve: When cutting in the axial direction, an end mill with the above-mentioned configuration applies an equal cutting load to both end cutting edges, which causes chipping and chipping, especially on the cutting edge on the auxiliary end cutting edge side. , etc. may occur frequently, and since both cutting edges are straight, it is difficult to cut in the cutting area where the rotation of the tool rotation center is close to zero, so it is mainly used only for cutting in the horizontal direction of the tool.

Purpose of the invention In view of the above-mentioned points, the present invention aims to reduce the cutting resistance exerted on the auxiliary end face cutting edge, prevent chipping and chipping of the cutting edge, and greatly improve tool life. It is an object of the present invention to provide a two-flute end mill that enables axial cutting and horizontal cutting of the tool and greatly improves work efficiency.

Means for Solving the Problems The present invention solves the above-mentioned problems by using the following configuration.

That is, at the tip of the tool body, there is a main end face cutting edge whose rotational projection plane in the tool axis direction is linear, the area around the center of the tool rotation axis is convex when viewed from the tip in the tool axis direction, and the outer circumferential side is linear; An auxiliary end face cutting edge is provided that extends linearly from
An outer circumferential cutting edge that is continuous with the main end cutting edge and the auxiliary end cutting edge is provided on the outer circumferential side of the tool body, and both ends are arranged so that the auxiliary end cutting edge is positioned inward in the tool axis direction from the main end cutting edge. 0.03~0.5mm between face cutting blades
This is a two-flute end mill with a step.

Effects of the Invention With the above-described configuration of the present invention, the cutting resistance applied to the auxiliary end face cutting edge is greatly reduced, and as a result, the tool itself is prevented from chattering, and the cutting edge is prevented from chipping or chipping. In addition, by making the cutting edge near the tool center of the main end face cutting edge convex, cutting starts from a point and moves to the surface, so cutting near the tool center where the rotation of the tool is close to zero is avoided. You can cut it as smoothly as you like.

These synergistic effects greatly improve tool life and result in an efficient, long-life two-flute end mill that can perform both axial and horizontal cutting with a single tool.

Embodiments Hereinafter, embodiments of the present invention will be described based on the attached drawings.

Reference numeral 1 denotes a tool body, in which two twisted grooves 11 and 12 are provided at radially symmetrical positions from the tip to the outer periphery, and cemented carbide twisted tips 2 and 3 are respectively loaded on one side of the twisted grooves. It is fixed by attaching or other means. At this time, as shown in FIG. 2, a wide portion 20 larger than the radius of the tool body 1 is integrally provided at the tip of one tip 2, and the tip is placed axially lower than the tip of the other tip 3. It is fixed with an extra step t protruding.

Note that Fig. 2 is a cross-section along the twisting direction of the chip, and the step t is slightly exaggerated to make it easier to understand, but the actual step t is
Set within the range of 0.03 to 0.5mm.

If the above-mentioned step is less than 0.03mm, the tool cannot follow the mounting error of the tool to the machine tool, and a large cutting load is applied to the auxiliary end face cutting edge, causing chatter and causing chipping or chipping of the cutting edge. . Furthermore, if the step exceeds 0.5 mm, only the main end face cutting edge will be involved in cutting, making efficient machining impossible.

After the chips 2 and 3 are fixed to the tool body 1 in this way, a main end face cutting edge 21 is formed at the tip of the chip, an outer peripheral cutting edge 23 is formed on the outer periphery, and an auxiliary end face cutting edge is formed at the tip of the other chip 3. forming a blade 31;
A peripheral cutting edge 33 is formed on the outer periphery.

In this case, each end face cutting edge 21, 31 and the outer peripheral cutting edge 2
3 and 33 are connected to each other via corner cutting edges 22 and 32 each having an appropriate radius. The main end face cutting edge 21 is formed long, extending from its outer periphery to near the axial center point O of the tool, and the auxiliary end face cutting edge 31 is formed short, extending from its outer periphery to an intermediate position in the radial direction. With the step t provided between the main end cutting edge 21 and the auxiliary end cutting edge 31,
1 and 31 are respectively inclined inward toward the axial center point O.

Furthermore, when viewed from the axial tip of the tool, the main end cutting edge 21 has a convex shape 21a near the rotation center toward the tool rotation direction, and a linear shape on the outer peripheral side, and the auxiliary end cutting edge 3
1 is formed in a straight line.

Note that the present invention may be implemented by modifying each part as follows.

That is, in the embodiment shown in FIG.
is formed into an L-shape with a wide part 20 at the tip of the main part, but this wide part 20 is formed separately from the main part, and when the two are butted and joined, the tool body is assembled. It may be fixed to 1.

In addition, each end face cutting edge 21, 31 and the outer peripheral cutting edge 23,
Instead of the rounded corner cutting edges 22 and 32, the corner cutting edges 33 may be connected to each other through an inclined linear corner cutting edge cut into a tapered slanted shape, or the corner cutting edge may be omitted and each end face Cutting blades 21, 31
The outer cutting edges 23 and 33 may directly intersect with each other.

In the main end cutting edge, the main end cutting edge 21 may be a curved cutting edge that is curved as a whole in a convex manner with respect to the rotational direction of the tool. In this case, the radius of curvature near the center of the tool is made smaller than the radius of curvature on the outer circumferential side.

The main end face cutting edge 21 is a straight cutting edge with a convex shape 21a near the center of the rotation axis toward the tool rotation direction, and a linear cutting edge near the outer periphery that is inclined toward the rear in the tool rotation direction as it reaches the outer periphery, and an auxiliary end face cutting edge. 31 may be formed in a straight line so as to be inclined toward the rear side in the rotational direction of the tool toward the outer periphery.

In the explanations and illustrations described above, an end mill with a twisted blade was used in which the twisted blade tips 2 and 3 were used and the peripheral cutting edges 23 and 33 were twisted blades.
This may be a straight edge end mill that uses a flat tip and has a straight outer peripheral cutting edge.In short, it is sufficient that the rotational projection of the outer periphery of the tool is linear when the tool is rotated.

Effect of the invention When using the two-flute end mill configured as described above, the main end face cutting blade 2 provided at the tip of the tool body
1 and the auxiliary end face cutting blade 31 perform axial cutting such as hole machining, and the outer peripheral cutting blades 23 and 33 perform horizontal cutting of the tool such as grooving and side cutting.

In this case, the auxiliary end cutting edge 31 is replaced by the main end cutting edge 21.
Since it is set back inward in the axial direction by the step t mentioned above, the main end face cutting edge 2
After cutting to a predetermined cutting depth in step 1, the auxiliary end face cutting blade 31 cuts so that it is covered, and the cutting resistance applied to the auxiliary end face cutting blade 31 is reduced, allowing smooth cutting. In addition, if chatter occurs during cutting due to errors in mounting accuracy of the tool or workpiece to the machine tool, this can be alleviated and absorbed within the range of the step t, so there is no risk of overload being applied to the auxiliary end cutting edge side. do not have. Moreover, when cutting soft materials, the work surface is elastically deformed by the main end face cutting blade 21 during cutting, and after passing through the main end face cutting blade 21, the work face is restored and is cut by the next auxiliary end face cutting blade 31. Although there is a risk that an extra cutting load may be applied at times, this can be absorbed within the range of the step t, so even soft materials can be cut smoothly. These prevent chipping and chipping on the cutting edges of the auxiliary end cutting edge and the main end cutting edge, increasing tool life and providing a highly accurate machined surface.

In addition, when viewed from the axial end of the tool, the main end cutting edge has a convex shape near the shaft center with respect to the rotational direction and a linear cutting edge on the outer peripheral side, making it possible to form a long effective cutting edge. The resistance is dispersed and the chips generated from the cutting edge are thinner and longer than the cutting edge. This is easy to break and greatly improves evacuation. Moreover, as mentioned above, the cutting edge at the center of the tool changes from a convex shape to a straight one, so cutting starts from a point and moves to a plane, and the rotation near the center of tool rotation becomes zero. Cutting of the end face (axial direction) of the tool including close areas can be performed smoothly and effortlessly.

Based on the above, the two-flute end mill devised in this invention is an efficient and long-life end mill that can significantly improve tool life and perform both axial and horizontal cutting with a single tool with high precision. It is something.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a partial sectional view along the tip twisting direction showing the procedure for soldering the chip, and Fig. 3 is an enlarged view of the tip in the axial direction of Fig. 1. It is a diagram. 1... Tool body, 2, 3... Chip, 21...
Main end cutting edge, 22...Corner cutting edge, 23...Outer cutting edge, 31...Auxiliary end cutting edge, 32...Corner cutting edge, 33...Outer cutting edge, t...Step.

Claims (1)

[Scope of utility model registration request] At the tip of the tool body, there is a main end face cutting edge with a straight rotational projection plane in the tool axis direction, a convex shape near the center of the tool rotation axis when viewed from the tip in the tool axis direction, and a straight line on the outer periphery. An auxiliary end face cutting edge is provided that extends linearly from the center point to a position in front of the tool body, and an outer peripheral cutting edge that is continuous with the main end face cutting edge and the auxiliary end face cutting edge is provided on the outer peripheral side of the tool body, and the auxiliary end face cutting edge is A two-flute end mill characterized in that a step of 0.03 to 0.5 mm is provided between both end face cutting blades so as to be positioned inward in the tool axis direction from the main end face cutting blade.