KR20230059851A - Cutting tool having a cooling path inside the tool - Google Patents

Abstract

Provided is a cutting tool having a tool interior cooling flow path. The cutting tool having the tool interior coolling flow path according to an embodiment of the present invention comprises: a core unit; a cutter provided on the outside of the core unit; and a cutter cooling channel located, in the cutter, adjacent to the cutting surface of the cutter. The cutter cooling channel is formed in the cutter as the core unit and cutter are formed by metal 3D printing. An objective of the present invention is to provide the cutting tool having the tool interior cooling flow path which can increase cutting precision, stability, and productivity in high-speed machining.

Description

Cutting tool having a cooling path inside the tool {CUTTING TOOL HAVING A COOLING PATH INSIDE THE TOOL}

The present invention relates to a cutting tool having a tool internal cooling passage, and more particularly, to a cutting tool having a tool internal cooling passage provided with a cooling passage inside the tool.

In general, machine tools are used for the purpose of processing metal workpieces into desired shapes and dimensions using appropriate tools by various cutting or non-cutting processing methods, such as CNC (Computerized Numerical Control) lathes or semi-automatic machines. There are types such as NC machines or machining centers.

Such a machine tool is provided with a cutting tool for performing cutting, and a tool holder coupled to a spindle to connect the spindle and the tool and fixing the tool.

On the other hand, conventional cutting tools such as solid end mills and drills are made by processing metal materials suitable for use as cutting tools, and have a completely solid structure in which cutting oil is supplied to the outside to cool the cutting heat, and cooling that can supply cutting oil There is a hollow structure in which a channel is provided as a hollow therein.

First, since a cutting tool having a completely solid structure to which cutting oil is supplied from the outside mainly cools the cutting heat generated on the outer surface of the cutting blade, it is difficult to release the cutting heat transmitted to the inside of the cutting blade.

Next, in the hollow structure cutting tool in which cutting oil is supplied to the inside, cutting oil can be supplied to the outside as well as to the inside to further cool the cutting heat that may be generated during cutting, but the machining of the cooling channel Due to the limitations, it is difficult to supply enough cutting oil to the area adjacent to the cutting edge.

That is, the cooling channel formed in the existing cutting tool is formed by drilling in the center of the cutting tool or its periphery, and it is difficult to form it near the cutting edge where cutting heat is concentrated. It is almost impossible to machine form the channel cross section.

As such, conventional cutting tools do not have sufficiently high cooling performance for the cutting edge where cutting heat is concentrated, so thermal deformation of the cutting surface occurs due to deterioration of the cutting edge and cutting chips in high-speed machining, or thermal deformation of the cutting tool In addition, there are problems in that a cutting tool is frequently replaced due to fatigue or breakage, or a device is frequently repaired, resulting in an increase in tact time and a decrease in productivity in the cutting process.

Korean Registered Patent No. 10-1917269

An object of the present invention to solve the above problems is to apply 3D printing technology to a cutting tool to form a cutting channel as close as possible to the cutting edge of the cutting tool, thereby improving cooling performance for the cutting edge compared to conventional cutting tools. It is to provide a cutting tool having a cooling passage inside the tool, which can sufficiently increase, and which can increase cutting precision, stability, and productivity in high-speed machining.

The technical problem to be achieved by the present invention is not limited to the above-mentioned technical problem, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

Configuration of the present invention for achieving the above object, the core portion; a cutter provided outside the core part; and a cutter cooling channel positioned adjacent to a cutting surface of the cutter in the cutter, wherein the cutter cooling channel is formed in the cutter as the core portion and the cutter are formed by metal 3D printing.

In an embodiment of the present invention, the cutter has a rake face corresponding to the cutting surface and a flank face corresponding to the guide of cutting chips, and the cutter cooling channel is disposed closer to the rake face than the flank face. can

In an embodiment of the present invention, the cutter cooling channel may have a cross-sectional shape extending from an edge portion of the cutter toward a boundary between the core portion and the cutter.

In an embodiment of the present invention, the cutter cooling channel may have a cross-sectional shape obtained by reducing the shape of the cutter.

In an embodiment of the present invention, the cross-sectional thickness between the rake face of the cutter and the cutter cooling channel may be less than 1/5 of the diameter of the core.

In an embodiment of the present invention, the cross-sectional thickness between the cutter's flank face and the cutter cooling channel is between 1.5 and 3 times the cross-sectional thickness between the cutter's rake face and the cutter cooling channel. can

In an embodiment of the present invention, a core cooling channel provided in the central portion of the core unit may further include.

In an embodiment of the present invention, the cutter and the cutter cooling channel are provided in a plurality of spiral shapes along the outer circumferential surface of the core portion, the core cooling channel is separated from the cutter cooling channel, and the core portion, the cutter, and the cutter The cooling channel and the core cooling channel may be formed of metal laminates along a central axial direction of the core.

In an embodiment of the present invention, the cutter cooling channel is adjacent to the rake face side, which is expressed as a portion where cutting heat is concentrated according to the analysis of the cutting thermal gradient of the cutter. A boundary or limit line of the passage cross section may be disposed there is.

In an embodiment of the present invention, the cutter cooling channel is expressed as a portion in which cutting heat is concentrated according to the cutting thermal gradient analysis of the cutter at a portion adjacent to the rake face side, and the thermal gradient is rapidly inclined. So as to be adjacent to A boundary or limit line of the passage cross-section may be placed.

In an embodiment of the present invention, the cutter cooling channel is expressed as a portion in which cutting heat is concentrated according to the cutting thermal gradient analysis of the cutter at a portion adjacent to the rake face side, and the thermal gradient is rapidly inclined. So as to be adjacent to A boundary or limit line of the passage cross section may be arranged corresponding to the isotherm of the thermal gradient.

The effect of the present invention according to the configuration as described above is to apply 3D printing technology to a cutting tool to form a cutting channel as close as possible to the cutting edge of the cutting tool, thereby sufficiently increasing the cooling performance of the cutting edge compared to conventional cutting tools. The present invention provides a cutting tool having a cooling passage inside the tool capable of increasing cutting precision, stability, and productivity in high-speed machining.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a front view of a cutting tool having a cooling passage inside the tool according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line I-I of FIG. 1 .
3 is a heat transfer analysis diagram showing a cutting heat gradient in a portion where cutting heat is concentrated in an existing cutting tool to which a cutter cooling channel according to an embodiment of the present invention is applied.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms, and therefore is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this is not only "directly connected", but also "indirectly connected" with another member in between. "Including cases where In addition, when a part "includes" a certain component, it means that it may further include other components without excluding other components unless otherwise stated.

Terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "include" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a front view of a cutting tool having an internal cooling passage according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line I-I of FIG. 1 .

1 and 2, a cutting tool 10 having a cooling passage inside the tool according to an embodiment of the present invention includes a core part 11 and a core cooling channel provided in the central part of the core part 11 ( 15), and a cutter 20 provided outside the core portion 11, and a cutter cooling channel 25 positioned adjacent to the cutting surface of the cutter 20 in the cutter 20.

The core part 11 is formed as a central structure of a tool to which the cutter 20 is coupled, and is a hollow structure in which a core cooling channel 15 penetrating the central part in the longitudinal direction is formed.

The core cooling channel 15 is a passage through which a cooling fluid such as cutting oil for cooling the core part 11 is supplied, but is presented in a circular cross-sectional shape as shown, but is not limited thereto, and makes the heat exchange area larger. It may have a concavo-convex shape for

In the core cooling channel 15, the cooling fluid flows along the center line of the core part 11.

As the cooling fluid, a fluid or gas used to cool the core part 11 by exchanging heat with the core part 11 while passing through the core cooling channel 15 may be used.

The cutter 20 is formed on the core part 11 at regular intervals to cut an object to be cut, and has an edge part 21 that is sharply processed and heat treated for cutting.

For example, the cutter 20 may have a spiral structure disposed at 90 degree or 180 degree intervals on the outside of the core part 11 provided in the shape of an end mill, but is not limited thereto, and may be arranged at smaller angular intervals. do.

The cutter cooling channel 25 is provided in a plurality of spiral shapes along the outer circumferential surface of the core portion 11 together with the cutter 20 inside the cutter 20 .

The cutter cooling channel 25 is a spiral passage in which a cavity is formed in the spiral direction of the cutter 20 corresponding to the shape of the cutter 20, and the cooling fluid supplied during cutting flows in the spiral direction.

The core cooling channel 15 and the cutter cooling channel 25, as separate structures, may be formed of a metal laminate along the central axial direction of the core portion 11.

The core part 11, the core cooling channel 15, the cutter 20, and the cutter cooling channel 25 are formed at the same time as metal used as a tool is laminated and formed by 3D printing.

The core cooling channel 15 is a straight structure and may be formed by drilling, but it is appropriate to form it together during metal lamination of 3D printing as described above in terms of saving later processing work.

The cutter cooling channel 25 provided in the cutter 20 is formed to have a cross-sectional structure corresponding to the shape of the cutter 20, and has a complicated cross-section and spiral arrangement similar to the shape of the cutter 20 without relying on metal lamination. is impossible, but it is possible enough with the 3D printing method, which is 3D printing.

The actual arrangement and cross-sectional structure of the cutter cooling channel 25 in the cutter 20 will be described in detail.

The cutter 20 has a rake face 22 corresponding to the cutting surface and a flank face 23 corresponding to the guide of cutting chips.

The rake face 22 has a concave curved shape, and the flank face 23 has a bulging curved shape, and the rake face 22 and the flank face 23 meet at the cutting edge 21 to form a cutting edge shape .

The flank face 23 serves to discharge the cut chips to the outside of the cutting surface, and frictional heat is reduced compared to the rake face 22 .

The cutter cooling channel 25 is disposed closer to the rake face 22 than the flank face 23, and facilitates cooling of the rake face 22, where frictional heat is mainly generated in cutting.

As such, the fact that the cutter cooling channel 25 is disposed adjacent to the rake face 22 rather than the flank face 23 is advantageous in terms of protecting the tool from heat generated during cutting and preventing thermal deformation of the cutting surface.

The cutter cooling channel 25 may have a cross-sectional shape extending from the edge portion 21 of the cutter 20 toward the boundary between the core portion 11 and the cutter 20 .

The structure extending from the edge portion 21 side of the cutter cooling channel 25 to the core side creates a pressure difference according to a flow velocity difference from the boundary side between the core portion 11 and the cutter 20 to the edge portion 21 side.

Accordingly, the cooling fluid can be easily supplied to the edge portion 21 to cool the edge portion 21, and compared to a conventional cutting tool in which cooling fluid is supplied from the core portion 11 side, to the edge portion 21 The cooling performance is significantly improved.

Substantially, the cutter cooling channel 25 may have a cross-sectional shape obtained by reducing the shape of the cutter 20 .

Meanwhile, the cross-sectional thickness T1 between the rake face 22 of the cutter 20 and the cutter cooling channel 25 may be less than 1/5 of the core diameter (diameter of the dotted line).

The outer cross-sectional thickness T1 of this cutter cooling channel 25 is used as a thickness dimension for making the cutter cooling channel 25 the maximum size corresponding to the shape of the cutter 20 while preventing damage to the cutter 20. can

For example, if the core diameter is 10 mm, the thickness of the cross section between the rake face 22 of the cutter 20 and the cutter cooling channel 25 must be about 2 mm to maintain the shape of the cutter 20 in cutting. there is.

In addition, the cross-sectional thickness T2 between the flank face 23 of the cutter 20 and the cutter cooling channel 25 is the cross-section between the rake face 22 of the cutter 20 and the cutter cooling channel 25 It may be formed between 1.5 and 3 times the thickness T1.

For example, if the cross-sectional thickness T1 between the rake face 22 of the cutter 20 and the cutter cooling channel 25 is 2 mm, the rake face 22 of the cutter 20 and the cutter cooling channel 25 The cross-sectional thickness (T2) between can be set to between 3 mm and 6 mm.

The cutter cooling channel 25 and the core cooling channel 15 may be coated and heat treated for corrosion and rigidity enhancement after metal lamination internally.

3 is a heat transfer analysis diagram showing a cutting heat gradient in a portion where cutting heat is concentrated in an existing cutting tool to which a cutter cooling channel according to an embodiment of the present invention is applied.

Referring to FIG. 3, the cutting tool is interpreted as a high temperature in the portion adjacent to the edge portion of the rake face, and a relatively low portion adjacent to the edge portion in the flank face on the opposite side. interpreted as temperature. This can be known through the temperature distribution and isothermal line displayed for each color.

Particularly, the area adjacent to the box marked T side on the rake face side is a portion where cutting heat is concentrated, and the cutting heat is expressed as a thermal gradient in which the temperature decreases along the inside of the cutter, the flank face, and the rake face.

It is expressed that the thermal gradient on the rake face side drops rapidly in the T side region, and the thermal gradient on the inside of the cutter and the flank face side gradually decreases on the rake face side.

Referring to the thermal gradient analysis of the cutter of the cutting tool of FIGS. 2 and 3, the cutter cooling channel 25 according to the present embodiment is more It is arranged so as to be close to the T side area adjacent to the rake face 22 side.

Preferably, the cutter cooling channel 25 is arranged so that the limit line of the cooling passage is as close as possible to points 1 and 2 in the T side region.

The limit line of the cross section of the flow path of the cutter cooling channel 25 is capable of maintaining the rigidity of the cutter 20 to prevent breakage and deformation of the rake face 22 side, that is, of the rake face 22 and the cutter cooling channel 25 If an appropriate thickness is provided, it can be sufficiently extended to the area adjacent to the T side area.

For example, the boundary or limit line of the passage section adjacent to the edge portion 21 in the cutter 20 of the cutter cooling channel 25 is a curve, straight line, or fine line similar to the orange isotherm between red and yellow in FIG. It may be provided in a shape including concave-convex lines.

Substantially, the cutter cooling channel 25 is adjacent to the rake face 22 side rather than the flank face 23 so as to sufficiently absorb heat in the red and orange regions included in the yellow box line outside the T side region. It is formed including a passage cross section corresponding to (20).

The above description of the present invention is for illustrative purposes, and those skilled in the art can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the present invention.

10: cutting tool 11: core part
15: core cooling channel 20: cutter
21: edge portion 22: rake face
23: flank face 25: cutter cooling channel

Claims (11)

core part;
a cutter provided outside the core part; and
a cutter cooling channel positioned adjacent to a cutting surface of the cutter in the cutter;
The cutter cooling channel,
A cutting tool having a cooling passage inside the tool, characterized in that formed on the cutter as the core portion and the cutter are formed by metal 3D printing.
The method of claim 1,
The cutter has a rake face corresponding to the cutting surface and a flank face corresponding to the guide of the cutting chips,
The cutting tool having a cooling passage inside the tool, characterized in that the cutter cooling channel is disposed closer to the rake face side than the flank face.
The method of claim 2,
The cutter cooling channel has a cross-sectional shape extending from an edge portion of the cutter toward a boundary between the core portion and the cutter.
The method of claim 3,
The cutting tool having a cooling passage inside the tool, characterized in that the cutter cooling channel has a cross-sectional shape obtained by reducing the shape of the cutter.
The method of claim 2,
A cutting tool having a cooling passage inside the tool, characterized in that the thickness of the cross section between the rake face of the cutter and the cutter cooling channel is formed to 1/5 or less of the diameter of the core.
The method of claim 5,
The thickness of the cross section between the flank face of the cutter and the cutter cooling channel is between 1.5 and 3 times the thickness of the cross section between the rake face of the cutter and the cutter cooling channel. Cooling channel inside the tool, characterized in that A cutting tool having
The method of claim 1,
A cutting tool having a cooling passage inside the tool, characterized in that it further comprises a core cooling channel provided in the central portion of the core portion.
The method of claim 7,
The cutter and the cutter cooling channel are provided in a plurality of spiral shapes along the outer circumferential surface of the core portion,
The core cooling channel is separated from the cutter cooling channel,
The core part, the cutter, the cutter cooling channel, and the core cooling channel are formed of metal laminates along the central axis direction of the core.
The method of claim 2,
The cutter cooling channel is characterized in that the boundary or limit line of the cross section of the flow path is disposed at a portion adjacent to the rake face side, which is expressed as a portion where cutting heat is concentrated according to the analysis of the cutting thermal gradient of the cutter. branch cutting tool.
The method of claim 2,
The cutter cooling channel is expressed as a portion where cutting heat is concentrated according to the cutting thermal gradient analysis of the cutter at a portion adjacent to the rake face side, and the thermal gradient is sharply inclined. A cutting tool having a cooling passage inside the tool, characterized in that.
The method of claim 2,
The cutter cooling channel is expressed as a portion where cutting heat is concentrated according to the cutting thermal gradient analysis of the cutter at a portion adjacent to the rake face side, and the boundary or limit line of the passage cross section is adjacent to the portion where the thermal gradient is steeply inclined. A cutting tool having a cooling passage inside the tool, characterized in that disposed corresponding to the isotherm of the thermal gradient.

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