JPH01127214A - Rough cutting end mill - Google Patents

Abstract

PURPOSE:To suppress self exciting chattering vibration further to facilitate regrinding by forming a waveform of the same shape in the same pitch in three or more sheets of peripheral edges equally divided by a fixed twist angle and ununiformly setting the phase displacement between the adjacent peripheral edges. CONSTITUTION:A rough cutting end mill 10, comprising a clamped shank part 12 and an edge part 14, provides peripheral edges 16a, 16b, 16c, 16d and twisting the edges all in a fixed twist angle further to be formed being equally divided in the circumferential direction, a waveform of the same shape is respectively formed in the sample pitch. Displacing the waveform in its phase in the axial direction little by little in every peripheral edge 16a, 16b, 16c, 16d the waveform is displaced by one pitch as a whole, and when the phase displacement of these waveforms is added, one pitch is obtained. Accordingly, ununiformly generating shape and area of a cut section by each cutting edge for a cut material while also a flow direction of chips and cutting resistance, self-exciting regenerative chattering vibration is suppressed from being generated. Accordingly, high efficient cutting can be performed, and the necessity for using a particular exclusive use device is eliminated when the cutting edge is worn performing regrinding.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a rough cutting end mill having a corrugated peripheral cutting edge, and more particularly to a technique for automatically suppressing the occurrence of regenerative chatter vibration during cutting.

One type of prior art end mill is one for rough cutting that has a corrugated outer cutting edge. This rough-cutting end mill has a corrugated peripheral blade that divides the chips, reducing the ejection resistance.
By deepening the cut into the work material, the specific cutting force is reduced, making heavy cutting possible and efficient machining.

By the way, the peripheral cutting edge of such a rough cutting end mill is generally twisted at a constant helix angle and equally divided into three or more pieces in the circumferential direction, and the waveforms formed on each of these peripheral cutting edges have the same shape. and are provided at the same pitch. In addition, the phases of the waveforms in the axial direction are shifted between the two adjacent peripheral blades,
This amount of phase shift is made equal between any adjacent peripheral blades. In other words, the amount of phase shift is usually set to a constant amount obtained by dividing (waveform pitch) by (number of peripheral blades), and the phase is shifted by that constant amount between adjacent peripheral blades. This allows the end mill to shift by one pitch per revolution.

Problems to be Solved by the Invention However, if the amount of phase shift between adjacent peripheral blades is equal in this way, each peripheral blade cuts equally during cutting, so the cutting resistance of each peripheral blade increases. are equal to each other and change at a constant period, and due to the constant periodic change in resistance, the tool 1 machine, the workpiece, etc. resonate and are likely to cause automatic regeneration and chatter vibration. Since such chatter vibration significantly impairs tool life and cut surface roughness, it is necessary to avoid this, and to do so, cutting conditions must be reduced, which limits machining efficiency. In addition, as a countermeasure against such chatter vibration, there are end mills such as unequal split blades with unequal spacing between the peripheral blades and unequal helix angle blades with unequal helix angles for each peripheral blade. There were problems such as the need for special dedicated equipment for grinding.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The purpose of this is to suppress the occurrence of automatic regenerative chatter vibration during cutting, thereby enabling highly efficient machining.

In order to achieve such an object, the present invention has three or more peripheral blades twisted at a constant helix angle and equally divided in the circumferential direction, and each of the peripheral blades has the same shape. In a rough cutting end mill in which waveforms are formed at the same pitch and the phases of the waveforms in the axial direction are shifted from each other between two adjacent peripheral blades, the phase shift between adjacent peripheral blades It is characterized by unequal amounts.

Function and Effect of the Invention In such a rough cutting end mill, the amount of phase shift of the waveform formed on the peripheral blade is uneven, so the cutting cross-sectional shape and cross-sectional area of the peripheral blade with respect to the work material are become uneven. Therefore, the flow direction of chips and the cutting resistance become uneven, and the occurrence of self-help regenerative chatter vibration is suppressed, which improves tool life and enables highly efficient machining.

In addition, in the rough cutting end mill of the present invention, three or more peripheral cutting edges are twisted at a constant helix angle and divided equally in the circumferential direction, so when the cutting edges wear out and are re-ground, the cutting edges are unevenly divided. There is an advantage that re-grinding can be easily and inexpensively carried out using a simple re-grinding method without using special dedicated equipment such as end mills with split blades or unequal helix angle blades.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

Figure 1 shows a rough cutting end mill 1 which is an embodiment of the present invention.
FIG. 2 is a front view showing 0. This rough cutting end mill 10 consists of a shank part 12 and a blade part 14 that are held by a milling machine, and the blade part 14 has four peripheral blades 16a, 16b,
16c and 16d (hereinafter simply referred to as the outer peripheral blade 16 unless otherwise specified) are provided. These peripheral blades 16 are all twisted at a constant helix angle T and are equally divided in the circumferential direction, that is, formed at 90° intervals, and each of these peripheral blades 16 has a waveform of the same shape. They are formed with the same pitch.

The phase of the waveform in the axial direction is as shown in FIG.
.

It is shifted little by little every 16d, and is shifted by 1 pitch P (1 seal) in total. That is, the adjacent peripheral blade 16
p+(tm) between a and 16b, peripheral blade 16b and 1
P between 6c! (tm), Ps (am) between the peripheral blades 16c and 16d, and P4 (crane) between the peripheral blades 16d and 16a, respectively, in the same direction (left-handed direction), The amount of phase shift P1.
When PZ, P3°P4 are added, one pitch P is obtained. In addition, these phase shifts IP+, Pz, P3
, Pa are set to different sizes.

In addition, the said FIG. 2 is a figure which showed the unevenness|corrugation in the direction perpendicular to the axial center of each peripheral blade 16 in the axial direction.

Such a rough-cutting end mill IO performs cutting on a workpiece (not shown) by having its shank portion 12 held by a milling machine (not shown) and rotating around its axis. The cut cross section of each peripheral blade 16 into the cutting material is shown by diagonal lines in FIG. Such third
The figure shows each peripheral blade 16 when the rough cutting end mill 10 is rotated twice, and the peripheral blades 16a-1, 1
6b-1, 16cm1.16d-1 is the one of the first rotation, and the peripheral blade 16a-2, 16b-2, 16cm2, 16d
-2 is the second rotation. In addition, cut cross sections A, B, C, and D indicated by diagonal lines are formed by the peripheral blades 16a, 16b, 16c, and 1'6d, respectively, in the second rotation. Note that the feed direction in FIG. 3 represents the relative movement direction of the roughing end mill 10 with respect to the workpiece.

As is clear from the above-mentioned FIG. 16 are different in the axial direction, it is possible to deepen the cut into the work material and reduce the specific cutting resistance, making heavy cutting and highly efficient machining possible.

Moreover, in this embodiment, the amount of phase shift of the waveform formed on each peripheral cutter 16 is P+, Pz, P5. Since Pa is uneven, the cutting cross sections A and B of the peripheral blades 16a, 16b, 16-c, and 16d on the workpiece.

The shape and cross-sectional area of C and D become uneven, and the direction of chip flow and cutting resistance also become uneven, which suppresses the occurrence of self-help regenerative chatter vibration, improves tool life, and improves rotation speed and feed. This makes it possible to increase the speed and perform cutting with even higher efficiency.

On the other hand, as shown in FIG. 6, the phase deviations P+, Pg, P3. When Pg is equal to each other, that is, when they are all 1/4 of 1 pitch P, the peripheral blades 16a, 16b, and 16c.

Cut cross sections A, B, and C for the work material of 16d.

Since the shape and cross-sectional area of D are equal to each other as shown in Fig. 7, the cutting resistance changes periodically and tends to cause automatic regenerative chatter vibration.To avoid this, There were disadvantages such as the need to use lighter cutting conditions. In addition, the above figures 6 and 7
The figures correspond to FIGS. 2 and 3, respectively.

On the other hand, in the rough cutting end mill lO of this embodiment, the four peripheral edges 16a, 16b, 16c, and 16d are twisted at a constant helix angle γ and equally divided in the circumferential direction, so that the cutting edges are not worn. When re-grinding is carried out, it is possible to perform re-grinding easily and inexpensively using a simple re-grinding method, without using special dedicated equipment such as end mills with unequal split blades or end mills with unequal torsional angular force. can.

Next, in order to clarify the effects of the present invention more specifically, the present invention products in which the phase shift amounts P l''P a are different, and the conventional products in which the shift amounts P and ~P4 are equal to each other are compared. The results of a performance test conducted by the inventors using this method will be explained.

First, the rough cutting end mill used has a blade diameter of 20 mm, a blade length of 38 mm, a handle diameter of 20 mm, a total length of 104 W1+, a number of peripheral blades of 4, a helix angle of the peripheral blade of 30°, and a waveform height. The length is 0.13n, the pitch of the waveform is 2.6Tsuru, and the material is 5KH.
59 (HRC is 67), and the waveform phase shift amount P,, pz, P, of the product of the present invention.

P4 is 0.5in, 0.8m, 0.6m, respectively.
At 0.7n+, the amount of phase shift P of the waveform of the conventional product,
P,,P.

tP4 is 0.65n (1 pitch 2.6 m/4
). Note that the direction of this phase shift is in the left-handed screw direction. In addition, the work material is Fe12 (HRB is 86
), and the cutting conditions were a cutting width of 30 m and a cutting depth of 1.
0m, upward cutting, no cutting oil, the machine used was vertical milling machine No. 4.

Then, the cutting rotation speed (rpm) and cutting feed rate (m
FIG. 4 shows the results of examining the occurrence of chatter vibration while changing the values (/l1lin). In FIG. 4, ○ and Δ are related to the product of the present invention, and .
and ■ are related to conventional products, ○ and · are free of chatter vibration, Δ and m are small chatter vibrations, and ■ are large chatter vibrations. In addition, the hatched range in the figure indicates the range in which the present invention product and the conventional product can be used satisfactorily, respectively, based on the above results, and the diagonal line downward to the left is the range for the present invention product. The diagonal line at the bottom right is the range of conventional products. Therefore, the usable range of the product of the present invention is clearly wider than that of conventional products, and by selecting the cutting conditions, high-efficiency machining is possible and tool life can be improved. be.

Although one embodiment and test results of the present invention have been described above in detail, the present invention can also be implemented in other embodiments.

For example, the outer peripheral cutter 1 of the rough cutting end mill 10 of the above embodiment
As is clear from FIG. 2, the waveforms 6 are all composed of curved lines, but as in the rough cutting end mill 20 shown in FIG. By forming a large number of grooves z4, it is also possible to cut the outer circumferential blade 22 into a comb-like shape to form a trapezoidal waveform.

Further, although the rough cutting end mill 10 of the above embodiment has four blades, the present invention can be similarly applied to a rough cutting end mill having three blades, five blades or more.

In addition, in the above embodiment, the phase shift amount P l"" P
Although a is determined to have a different size, for example, P, -P, ≠ Pz = Pa, if the four deviations P, ~P4 are unequal, this is the object of the present invention. Effects can be obtained.

Although other examples are not provided, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a front view of a rough cutting end mill that is an embodiment of the present invention. FIG. 2 is a diagram illustrating the phase shift of the waveform formed on the peripheral cutting edge of the rough cutting end mill shown in FIG. 1. FIG. FIG. 3 is a diagram illustrating a cross section cut by the rough cutting end mill of FIG. 1. FIG. 4 shows the results of investigating the usable cutting condition range using an example of the product of the present invention, and is a diagram showing a comparison with a conventional product. FIG. 5 is a front view showing another embodiment of the present invention. FIG. 6 is a diagram illustrating the phase shift of the waveform formed on the peripheral cutting edge of a conventional rough-cutting end mill, and corresponds to FIG. 2. FIG. 7 is a diagram illustrating a cutting cross section by a conventional rough cutting end mill, and corresponds to FIG. 3. 10.20: Rough cutting end mill 16a, 16b, 16c, 16d, 22: Peripheral blade P: 1
Pitch Pl+ Pz, Ps, Pa: Phase deviation ratio Onisugi Co., Ltd. Figure 1 Figure 5 Figure 3 /-m-N ≧Sono-G Co., Ltd.

Claims (1)

[Claims] It has three or more peripheral blades twisted at a constant helix angle and equally divided in the circumferential direction, each of which has waveforms of the same shape formed at the same pitch. ,
A rough cutting end mill in which the phase of the waveform in the axial direction is shifted from each other between two adjacent peripheral blades, characterized in that the amount of phase shift between the adjacent peripheral blades is made uneven. Rough cutting end mill.