CN113070517A

CN113070517A - End milling cutter for machining metal shell and machining method

Info

Publication number: CN113070517A
Application number: CN202010010683.4A
Authority: CN
Inventors: 梁芫豪; 曾仲煜; 刘彦廷; 陈宥任; 黄圣杰; 黄银; 万鑫; 李讷
Original assignee: Asustek Computer Inc
Current assignee: Asustek Computer Inc
Priority date: 2020-01-06
Filing date: 2020-01-06
Publication date: 2021-07-06
Also published as: TW202126412A

Abstract

The invention provides an end mill for processing a metal shell and a processing method. The end mill includes a shank portion and a milling portion. The shank portion defines a central axis of rotation. The milling portion extends from the shank portion in a direction away from the shank portion along the central axis of rotation. The milling portion includes at least one cutting edge and an end surface. The blade surrounds the rotation central axis and extends to the end surface. The end surface is a convex curved surface. The invention also provides a machining method using the end milling cutter.

Description

End milling cutter for machining metal shell and machining method

Technical Field

The present invention relates to a machining tool for machining a metal shell, and more particularly, to an end mill for machining a metal shell and a machining method thereof.

Background

With the technological progress, the market of electronic products is more competitive. To highlight the difference of products, the visual and tactile effects that the shell can exhibit are also increasingly emphasized. As for the metal shell, besides the texture of the metal material itself, many different surface treatment techniques, such as surface wire drawing and surface coloring, have been developed to improve the texture.

Conventionally, in order to present a mirror pattern, such as a trademark or other marks, on the surface of a metal shell, it is usually necessary to perform a cutting and polishing process on a specific region (i.e., a pattern portion) of the metal shell, form the pattern by using the cutting process, and remove tool marks left by the cutting process by using the polishing process. The process of this method is cumbersome, and the polishing process is prone to damage other surface portions of the metal case.

Disclosure of Invention

The invention provides an end mill. The end mill includes a shank portion and a milling portion. The shank portion defines a central axis of rotation. The milling portion extends from the shank portion in a direction away from the shank portion along the central axis of rotation. The milling portion includes at least one cutting edge and an end surface. The blade surrounds the rotation central axis and extends to the end surface. The end surface is a convex curved surface.

The invention also provides a machining method using the end milling cutter. The processing method comprises the following steps: providing a metal shell; and cutting a pattern on the surface of the metal shell by using an end milling cutter, wherein the end milling cutter comprises a milling part, the milling part comprises an end surface, and the end surface is an outer convex curved surface.

The end milling cutter provided by the invention can instantly remove the generated cutting waste chips in the cutting process, avoid the cutting waste chips attached to the cutting edge from scratching the surface and improve the cutter marks on the processed surface. Thus, after the cutting process, the mirror pattern can be formed without applying an additional polishing process.

The present invention will be further described with reference to the following examples and accompanying drawings.

Drawings

FIG. 1 is a perspective view of one embodiment of an end mill of the present invention;

FIG. 2 is an enlarged view of portion A of the end mill of FIG. 1;

FIG. 3 shows a metal shell after machining using the end mill of FIG. 1; and

fig. 4 is an enlarged view of the region B in fig. 3.

Detailed Description

The following describes in more detail embodiments of the present invention with reference to the schematic drawings. Advantages and features of the present invention will become apparent from the following description and claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

Fig. 1 is a perspective view of an embodiment of an end mill of the present invention. Fig. 2 is an enlarged view showing a portion a of the end mill of fig. 1. The end mill is suitable for forming a pattern, especially a high-brightness mirror pattern, on the surface of a metal shell.

As shown in fig. 1, the end mill 10 includes a shank portion 12 and a milling portion 14. The shank portion 12 is adapted to be mounted to a machining apparatus, such as a milling machine or a CNC machine tool. The shank portion 12 defines a central axis of rotation a 1. The central axis of rotation a1 is the axis of rotation for the end mill 10 during milling operations.

The milling portion 14 extends from the shank portion 12 in a direction away from the shank portion 12 along the central axis of rotation a 1. Referring also to fig. 2, the milling portion 14 includes two

cutting edges

142a,142b and an end surface 144. The

blades

142a,142b encircle the central axis of rotation a1 and extend to the end surface 144, and form a blade cutting surface at the end surface 144. A chip removing groove 143 is formed between the two

blades

142a,142b to remove chips generated from the cutting surfaces of the

blades

142a,142 b.

In one embodiment, as shown, the

blades

142a,142b may be helically wound around the central axis of rotation a 1. But is not limited thereto. The

blades

142a,142b may also extend longitudinally along the central axis of rotation a1 to the end surface 144. Next, in one embodiment, as shown in the figures, the

cutting edges

142a,142b are symmetrically distributed on the milling portion 14 with the rotation center axis a1 as the center of symmetry to avoid the unbalanced condition generated during the rotation of the end mill 10.

In this embodiment, the milling part 14 has two

cutting edges

142a,142b symmetrically distributed over the milling part 14. But is not limited thereto. In one embodiment, the number of cutting edges provided by the milling portion 14 can be reduced to one. In one embodiment, the milling portion 14 has a number of cutting edges between 2 and 4.

The end surface 144 is a convex curved surface, i.e., convex in the direction of the cutting surface. The end surface 144 projects outward about the center axis of rotation a 1. The shape of the end surface 144 helps to smoothly discharge the chips cut by the edge 144b of the end surface 144 along the chip discharge groove 143. In one embodiment, the convex curved surface may be a spherical surface or an ellipsoidal surface. In one embodiment, the width of the chip removal groove 143 is greater than or equal to the width of the

cutting edges

142a,142 b.

To avoid excessive waviness of the end mill 10 on the cutting face, while ensuring that cutting chips can be smoothly removed from the edge 144b of the end face 144. In one embodiment, the height difference H1 between the edge 144b of the end surface 144 and the center 144a of the end surface 144 is less than or equal to 0.2 mm. In one embodiment, end surface 144 is spherical and has a radius of curvature R1 that is greater than an outer diameter D1 of milling portion 14. In one embodiment, the spherical surface has a radius of curvature R1 that is greater than 1.8 times the outer diameter D1 of milling portion 14.

Fig. 3 shows a metal shell machined using the end mill of fig. 1. The arrows in the figure show the machining path of the end mill. Fig. 4 is an enlarged view of the region B in fig. 3. The following description will be made with respect to the machining process and the operating conditions of the end mill.

As shown in fig. 3, a pattern 22 is formed on the surface 20a of the metal shell 20 by cutting with the end mill 10. In one embodiment, the metal casing 20 may be an aluminum alloy casing, an aluminum magnesium alloy casing, or a titanium alloy casing. In one embodiment, the metal shell 20 may be a metal shell with a surface treatment (e.g., surface painting, surface frosting) or a metal shell without a surface treatment.

The machining process requires the selection of a suitable end mill 10 depending on the pattern to be formed. In one embodiment, the milling portion 14 of the end mill 10 is selected to have an outer diameter D1 that is less than the minimum line width w1 of the pattern 22. As shown in fig. 4, the end mill 10 has a plurality of slightly concave surfaces formed on the bottom surface of the pattern 22 by partially overlapping the processing path P1 in the pattern 22. The concave surfaces can effectively reflect ambient light and show mirror effect at different visual angles.

In one embodiment, in order to avoid damage to the end mill 10 and ensure that cutting debris can be smoothly removed from the edge of the cutting edge, the cutting depth T1 of the end mill 10 can be less than 0.3mm and the rotation speed of the end mill 10 can be greater than 3 thousand revolutions during the machining process. In one embodiment, the depth of cut T1 is greater than the height difference H1 between the face edge 144b and the face center 144 a.

Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. An end mill for machining a metal shell, comprising:

a shank portion defining a central axis of rotation; and

and a milling portion extending from the shank portion in a direction away from the shank portion along the central axis of rotation, the milling portion including a cutting edge and an end surface, the cutting edge surrounding the central axis of rotation and extending to the end surface, the end surface being a convex curved surface.

2. The end mill for machining a metal shell according to claim 1, wherein the end face is centered on the central axis of rotation.

3. The end mill as claimed in claim 1, wherein said convex curved surface is a spherical surface or an ellipsoidal surface.

4. The end mill for machining a metal shell as claimed in claim 3, wherein said spherical surface has a radius of curvature greater than an outer diameter of said milled portion.

5. The end mill for machining a metal shell according to claim 4, wherein a radius of curvature of the spherical surface is 1.8 times or more an outer diameter of the milled portion.

6. The end mill for machining a metal shell as claimed in claim 1, wherein the number of said cutting edges is 2 to 4.

7. The end mill for machining a metal shell according to claim 1, wherein a height difference between an edge of the end face and a center of the end face is 0.2mm or less.

8. The end mill according to claim 1, wherein the cutting edge is helically wound around the central axis of rotation.

9. A method of machining using an end mill, the method comprising:

providing a metal shell; and

and cutting a pattern on the surface of the metal shell by using an end mill, wherein the end mill comprises a milling part, the milling part comprises an end surface, and the end surface is a convex curved surface.

10. The method of claim 9, wherein the outer diameter of the milled portion of the end mill is less than the minimum line width of the pattern.

11. The method of claim 9 wherein said end mill has a depth of cut of less than 0.3 mm.

12. The method of claim 9 wherein said end mill rotates at a speed greater than 3 thousand revolutions.