JPH0650720U - Cutting tool for soft materials - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to improvement of a cutting tool for processing a soft material such as expanded polystyrene. [Structure] Two outer peripheral blades 4 are provided on the outer peripheral surface of the tool body 1 to set a twist angle φ of 40 degrees or more, a rake angle γ of 50 degrees, and a clearance angle α of 20 degrees. An outer peripheral radiused portion 8 that bends inward from the outer periphery with a radius of curvature r that is less than or equal to the radius of the tool axis, and a central flat portion 9 that is continuous with the inside of the outer peripheral radiused portion 8 are provided. Then, in the outer peripheral rounded portion 8, the two spiral blades 5 that spirally connect the tip end portion e of the outer peripheral blade 4 and the central flat portion 9 to each other.
Is provided, and the rake angle γ of the spiral blade 5 with respect to each radial surface x-R of the outer peripheral rounded portion 8 is constant at 50 degrees, and the clearance angle α is constant at 20 degrees.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a cutting tool for processing soft materials such as Styrofoam.

[0002]

[Prior art]

 BACKGROUND ART Heretofore, a casting method such as a full molding method in which a disappearing foam block is used for casting when a die such as a press die is manufactured is known. That is, in this method, a foam block is cut to produce a vanishing model of the same shape as the mold, and after the vanishing model is solidified with sand such as resin sand, the molten metal is poured into the model section to cast the model. It is made to disappear and a mold of the same shape as the model is cast. Therefore, as a cutting process for processing such a foam block, for example, as in Japanese Utility Model Laid-Open No. 59-187421, devil-like cutting blades are formed at equal pitch intervals on the rotation direction side of the twist groove provided on the outer periphery. Tools that have been used are known. The applicant has also disclosed a tool such as Japanese Utility Model Application No. 04-073 986 as a cutting tool for such foam blocks. This tool optimizes the combination of the helix angle of the outer peripheral blade on the outer peripheral surface of the tool body, the rake angle with respect to the cross section perpendicular to the axis, and the clearance angle with respect to the cutting surface to smooth the cutting surface and slice the chips. It is intended to improve casting quality and environmental hygiene.

[0003]

[Problems to be solved by the device]

 However, in the case of a cutting tool such as the one described above, although it is effective when machining while rotating the tool, for example, while feeding it in the direction orthogonal to the tool axis, it is effective in the tool axis direction like window punching or through machining. It was not applicable when processing while sending. In addition, when attempting to perform such processing using a conventional general cutting tool, there is a problem that the chips become powdery and scatter in the working space to deteriorate the environment.

[0004]

In order to solve such a problem, the present invention provides a peripheral blade provided on the outer peripheral surface of a tool body with a twist angle of at least 40 degrees with respect to the tool axis and a rake angle of 40 degrees with respect to a cross section orthogonal to the axis. Degree to 60 degrees, the clearance angle to the finished surface is within 20 degrees, and the cutting tool has a tip pocket inside the cutting edge. An outer peripheral radius part that bends inward with a radius of curvature and a central flat part that connects to the inside of the outer peripheral radius part are provided, and the straight end part of the outer peripheral blade parallel to the axial direction and the central flat part are spirally formed in this outer peripheral radius part. A spiral blade to connect to was added. The rake angle of the spiral blade with respect to each radial surface of the outer peripheral radius portion is kept constant within the range of 40 to 60 degrees. Further, the outer peripheral blade and the spiral blade connected to the outer peripheral blade have at least two threads.

[0005]

[Action]

 The combination of the helix angle, rake angle and clearance angle of the outer peripheral blade provided on the outer periphery of the tool body is used to smooth the cutting surface and slice the chips when machining while feeding the tool mainly in the direction perpendicular to the tool axis. It is effective, and the rake angle of the spiral blade provided on the outer peripheral radius of the tool tip is effective for slicing chips when machining while mainly feeding the tool in the axial direction. Therefore, powdery chips do not scatter in the work space during window punching and threading, and environmental hygiene is not deteriorated.

[0006]

【Example】

 An embodiment of a cutting tool for soft materials according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of the tip of the present cutting tool, FIG. 2 is a plan view of the same, and FIG. 3 is a front view of the tip with a partial cross section.

The cutting tool of the present invention has been proposed as a tool for manufacturing a vanishing model such as styrofoam. As shown in FIG. 3, the tool body 1 includes a body portion 2 having a blade portion and a shank. It comprises a part 3.

The body 2 is provided with two outer peripheral blades 4 on the outer peripheral surface parallel to the tool axis OO, and two spiral blades 5 are provided on the tip side of the body 2. The outer peripheral blade 4 and the spiral blade 5 are continuous.

The outer peripheral blade 4 has a twist angle φ of 40 degrees or more with respect to the tool axis OO, and as shown in FIG. 4, which is a partially enlarged sectional view of the outer peripheral blade 4, a cross section Q- The rake angle γ with respect to Q is in the range of 40 to 60 degrees. Further, the clearance angle α with respect to the cutting finished surface PP is set within 20 degrees. In the case of the embodiment, the rake angle γ is 50 degrees and the clearance angle α is 20 degrees. That is, the thickness angle δ of the cutting edge where the rake face 6 and the flank face 10 intersect is set to 20 degrees.

A chip pocket 7 is formed inward from the rake face 6 to smooth out chip discharge.

When the tool body 1 is rotated and fed in the direction perpendicular to the tool axis OO, the outer peripheral blade 4 cuts the cutting surface P-P. By having such a strong twist angle φ, the so-called pull-cut effect is exhibited and the cut surface can be finished neatly.

Further, when the rake angle γ with respect to the cross section Q-Q perpendicular to the axis is small, the cutting edge is in a standing state, and a force for peeling off the chips acts. If the rake angle γ is set to a large value of about 50 degrees, the cutting edge will be in a state in which it is lying down, and the shape will not be peeled off.

Then, by combining the twist angle φ, the rake angle γ, and the clearance angle α, if the tool is sent in the direction perpendicular to the tool axis OO, the chips can be machined into slices and the cutting surface can be finished neatly. It has been confirmed by experiments that cutting efficiency can be improved as well as possible.

By the way, in the case of the present invention, the rake angle γ50 °, the clearance angle α20 °, and the thickness angle δ20 ° of the cutting edge are also kept constant in the spiral blade 5 on the tip side of the body portion 2.

That is, as shown in FIG. 3, an outer peripheral rounded portion 8 that bends inward from the outer periphery is provided on the tip side of the body portion 2, and the radius of curvature of the outer peripheral rounded portion 8 from the center of curvature x. r is less than or equal to the radius of the tool axis. The inside of the outer peripheral rounded portion 8 is a central flat portion 9, and the front surface is flat.

That is, as shown in FIG. 2, the inside of the circle (broken line) centering on the tool axis center O is the central flat portion 9, and the outside thereof is the outer peripheral rounded portion 8.

Further, a spiral blade 5 is provided at the tip of a tip portion (straight end portion e) parallel to the tool axis (OO line) of the outer peripheral blade 4, and the spiral blade 5 has an outer periphery. It is provided in a spiral shape along the rounded portion 8 and is connected to the central flat portion 9 by turning about 180 degrees from the straight end portion e. Further, in the case of the embodiment, the two spiral blades 5 connected to the central flat portion 9 are joined at positions facing each other. The turning angle of the spiral blade 5 is not necessarily 180 degrees, and may be 270 degrees, for example.

Next, the shape of the spiral blade 5 will be described with reference to FIG. FIG. 5 is an axial sectional view of the spiral blade, (a) is a sectional view taken along the line AA of FIG. 2, (b) is a sectional view taken along the line OB of FIG. 2, and (c) is a sectional view taken along the line O- of FIG. 2 is a sectional view taken along the line C-D of FIG. 2, and FIG.

As described above, the rake angle γ50 degrees, the clearance angle α20 degrees, and the cutting edge thickness angle δ20 degrees are maintained in all parts of the spiral blade 5. That is, as shown in (b) and (d) of FIG. 5, the rake angle γ with respect to the radial surface x-R centering on the center of curvature x of the outer peripheral rounded portion 8 is constant at 50 degrees, and the cutting finish is The clearance angle α with respect to the plane P-P is constant at 20 degrees. In addition, this spiral blade 5 is also provided with a chip pocket which is continuous with the rake face, like the outer peripheral blade 4.

The swivel angle of the spiral blade 5 corresponds to the helix angle φ of the outer peripheral blade 4. When the spiral swivel angle is 180 degrees as in the embodiment, the tool diameter is 30 mm and the outer radius rounded portion 8 is When the radius of curvature r is 10 mm, it corresponds to a twist angle φ78.8 degrees. Incidentally, when the turning angle of the spiral is 270 degrees, it corresponds to the twist angle φ82 degrees.

With the configuration of the spiral blade 5, the cutting surface can be finished neatly even when the rotating tool body 1 is fed in the axial direction, and the chips can be sliced. In other words, window punching, threading, etc. are finished neatly, and there is no defect that chips are scattered.

It should be noted that the spiral blade 5 and the outer peripheral blade 4 may have more than two threads as in the embodiment, and the cutting tool of the present invention is not limited to the soft material shown in the embodiment and may be, for example, It goes without saying that it can also be applied to other resin materials and wood.

[0023]

[Effect of device]

 As described above, the cutting tool for soft material of the present invention can form chips in a slice shape even when cutting while feeding the tool in the axial direction such as window punching or threading of a foam block. Moreover, the finished surface can be finished neatly. Therefore, it is possible to prevent problems such as chips being scattered around and impairing environmental hygiene, and the cutting surface being rough and being used as, for example, a model for disappearing a die, causing sand trapping.

[Brief description of drawings]

FIG. 1 is a perspective view of the tip of the present cutting tool.

FIG. 2 is a plan view of the same.

FIG. 3 is a front view with a tip partly in section

FIG. 4 is a partially enlarged sectional view of a peripheral blade.

5 is an axial cross-sectional view of the spiral blade, (a) is a cross-sectional view taken along the line AA of FIG. 2, (b) is a cross-sectional view taken along the line OB of FIG.
(C) is a sectional view taken along the line O-C of FIG. 2, and (D) is a line O-D of FIG.
Line cross section

[Explanation of symbols]

 1 Tool body 4 Outer peripheral blade 5 Helical blade 8 Outer peripheral radius portion 9 Central flat portion α Clearance angle γ Rake angle φ Twist angle e Straight end portion r Curvature radius

Claims (2)

[Scope of utility model registration request] 1. A peripheral edge provided on an outer peripheral surface of a tool body has a twist angle of at least 40 degrees with respect to a tool axis, a rake angle of 40 degrees to 60 degrees with respect to a cross section orthogonal to the axis, and a clearance angle of 20 degrees with respect to a cutting surface. In a cutting tool having a chip pocket inside and inside the cutting edge portion, at the tip of the tool body, an outer peripheral radiused portion curved inward from the outer periphery with a radius of curvature not larger than the radius of the tool shaft and the outer peripheral radiused portion. A central flat portion that is continuous inside the portion is provided, and the outer peripheral rounded portion is provided with a spiral blade that spirally connects the straight end portion of the outer peripheral blade parallel to the axial direction and the central flat portion, and each of the outer peripheral rounded portions. A cutting tool for soft materials, characterized in that the rake angle of a spiral blade with respect to a radial surface is kept constant within a range of 40 to 60 degrees. 2. The cutting tool for soft material according to claim 1, wherein the outer peripheral blade and the spiral blade connected to the outer peripheral blade have at least two threads.