Hole making tool for aramid fiber-reinforced plastic and design method thereof

Patent metadata

Field	Value
Publication number	US-12397384-B2
Application number	US-202318350921-A
Country	US
Kind code	B2
Filing date	Jul 12, 2023
Priority date	Jul 15, 2022
Publication date	Aug 26, 2025
Grant date	Aug 26, 2025

Abstract

The present invention belongs to the technical field of composite material processing, and relates to a hole making tool for aramid fiber-reinforced plastic and a design method thereof. The drill bit has a step reversed point angle structure, which can reduce a trust force during drilling and effectively cut off a high toughness aramid fiber, thus to improve the hole making quality of an AFRP-related component. It is proved that the new tool can significantly improve the hole making quality of an AFRP component, improve the service life and safety degree, and greatly reduce the processing cost. Therefore, the present invention has a broad application prospect in the fields of aerospace, military industries and civil application.

First claim

The invention claimed is:

1. A design method of a hole making tool for aramid fiber-reinforced plastic, wherein the hole making tool for aramid fiber-reinforced plastic, comprising four regions: a multiple point angle drill tip region, a reversed point angle reaming region, a reaming region and a shank clamping region;
the multiple point angle drill tip region comprises a twist drill, and has a tool diameter of D 1 ; the width of a chisel edge 1 is b 1 , a major cutting edge is divided into a major cutting edge first part and a major cutting edge second part to form a double point angle structure which comprises a major cutting edge first point angle N 1 and a major cutting edge second point angle N 2 , corresponding radial widths are respectively a first part radial length b 2 of the major cutting edge first part and a second part radial length b 3 of the major cutting edge second part, and a width ratio is determined according to actual processing requirements; a rake face and a flank face of the tool are ground to form a major cutting edge rake angle γ 1 and two major cutting edge relief angles which are respectively a major cutting edge primary relief angle α 1 and a major cutting edge secondary relief angle α 2 ;
the reversed point angle reaming region comprises a reversed point angle structure, a second step part of the tool is ground to obtain a reversed point angle which is P, a drill margin width is b 4 , a drill margin depth is b 5 , the maximum length of the reversed point angle structure is b 6 , a major cutting edge rake angle of the reversed point angle structure is γ 2 , and a major cutting edge relief angle of the reversed point angle structure is α 3 ; as a first step diameter and a second step diameter are different, a helix angle N 3 of a chip groove and the width b 7 of the chip groove in the two steps shall be appropriate;
the tool diameter of the reaming region is the second step diameter D 2 , the reaming region has a drill margin and a taper of 3:1000, and the diameter near a minor cutting edge is large;
the diameter of the shank clamping region is a shank diameter D 3 , and a clamping length is determined according to actual clamping requirements;
the design method of the hole making tool for aramid fiber-reinforced plastic, which optimizes a step diameter ratio and point angles of the tool; first, the attribute parameters of a material to be processed, including an AFRP bonding interface equivalent modulus k b , a bonding strength σ b , an elastic modulus E f of a lower surface material, a moment of inertia of the section I f of the lower surface material, a single-layer fiber thickness t, a feed per tooth v, an end hole design diameter D 2 , the step diameter ratio n, a bottom layer debonding fiber length L, a half point angle φ of the tool, and a fiber deflection change z are determined; and the design method comprises the following specific steps:
step 1: inputting the single-layer fiber thickness t and the feed per tooth v to calculate the relationship of a radial component force F X and an axial component force F Z with the half point angle φ of the tool;
step 2: inputting the bonding interface equivalent modulus k b , the bonding strength limit σ b , the elastic modulus E f and the moment of inertia of the section I f according to the criteria for judging fiber material debonding to calculate a fiber deflection deformation equation:

z
=

e

k
b

/
4

⁢

E
f

⁢

I
f

-
4

⁢
x

(

K
1

⁢
cos
⁢

k
b

/
4

⁢

E
f

⁢

I
f

4

⁢
x

+

K
2

⁢
sin
⁢

k
b

/
4

⁢

E
f

⁢

I
f

4

⁢
x

)

+

e

k
b

/
4

⁢

E
f

⁢

Assignees

• Univ Dalian Tech

Inventors

• Wang Fuji
• Zhao Hongwei
• Fu Rao
• Zhao Meng
• Yin Dekun
• Jia Zhenyuan

Classifications

• B23P15/46

  reaming tools · CPC title

• B23B2226/27

  Composites · CPC title

• B23B51/08 Primary

  Drills combined with tool parts or tools for performing additional working {(B23G5/20 takes precedence)} · CPC title

• B23B51/02

  Twist drills · CPC title

• B23P15/32 Primary

  twist-drills · CPC title