CN-116728614-B - High-sharpness strong self-sharpening trepanning drill for ceramic matrix composite small hole machining

CN116728614BCN 116728614 BCN116728614 BCN 116728614BCN-116728614-B

Abstract

The invention discloses a high-sharpness self-sharpening trepanning drill for ceramic matrix composite material small hole machining, which comprises a cutter matrix framework provided with a groove structure and diamond abrasive particles with composite particle diameters brazed on the matrix framework, wherein the cutter matrix framework is of a hollow cylindrical structure, a plurality of crossed evenly-distributed inner and outer grooves are designed at the working end, and the diamond abrasive particles in the inner and outer grooves are brazed on the inner and outer grooves, wherein the diamond abrasive particles in the inner and outer grooves can enhance the cutting capability, the particle diameter of the diamond abrasive particles is larger than that of the diamond abrasive particles (ensuring the hole making precision) on the outer peripheral surface of the working section, and after the sharpness of a drill bit is reduced due to abrasion of the diamond abrasive particles, the abrasive particles in the groove structure start to fall out to participate in machining. The trepanning drill structural design can keep the cutter in a high sharp state, improve the drilling quality and the trepanning drill service life, and meet the requirements of high-efficiency high-quality low-cost machining of ceramic matrix composite pinholes.

Inventors

QIAN NING
XU JIUHUA
XU PENGFEI
HE JINGYUAN
SU HONGHUA
YIN JINGFEI
Angie Rama
WANG XINGCHAO
ZHAO BIAO
DING WENFENG

Assignees

南京航空航天大学
中国航发沈阳黎明航空发动机有限责任公司

Dates

Publication Date: 20260512
Application Date: 20230417

Claims (2)

1. A high sharpness self-sharpening trepanning drill for ceramic matrix composite pinhole processing, comprising: (1) A cutter matrix skeleton; (2) Composite grain diameter diamond abrasive particles brazed on the inner and outer surfaces of the working end of the cutter matrix skeleton; The cutter matrix skeleton is of a hollow cylindrical structure, the working end is provided with a plurality of groove structures, the groove structures comprise outer grooves axially arranged on the outer circular surface and inner circular surface of the working end of the cutter matrix skeleton, the inner grooves and the outer grooves are uniformly distributed in a crossing manner on the inner circular surface and the outer circular surface of the working end and are not communicated with each other, and the rigidity of the matrix is ensured; The diameter of the trepanning drill is 0.7-2 mm, and the length of the groove-shaped structure is smaller than that of the working end; The diamond abrasive particles with the composite particle size are brazed on an inner groove, an outer circular surface of a working end and an inner circular surface of the working end, wherein the diamond abrasive particles of the inner groove and the outer groove are consistent in particle size, the diamond abrasive particles of the inner circular surface and the outer circular surface of the working end are consistent in particle size, the cross section of the groove-shaped structure is trapezoid or arc, and the number of the outer groove and the number of the inner groove are respectively N, and N is more than or equal to 2; the composite grain diameter diamond abrasive particles brazed on the inner and outer circular surfaces of the working end are diamond abrasive particles with a first grain diameter, and the arrangement of the composite grain diameter diamond abrasive particles is designed based on the drilling size so as to ensure the drilling precision; The diamond abrasive particles brazed in the inner groove and the outer groove are diamond abrasive particles with a second particle size, and the arrangement of the diamond abrasive particles is selected based on the groove size, so that the cutting capability is enhanced; When the sharpness of the drill bit is reduced due to abrasion of the diamond abrasive particles with the first particle size, the abrasive particles in the groove structure start to fall out to participate in processing, so that the self-sharpening effect of the trepanning drill is enhanced, and the high sharpness of the trepanning drill is ensured; The thickness of the matrix is 0.5 times that of the groove structure, so that diamond abrasive particles in the outer groove and the outer circular surface of the working end are ensured to mutually cross in the axial direction; The width of the groove structure is larger than the diameter of the diamond abrasive particles, the length is smaller than the length of the working end of the trepanning drill.
2. The high-sharpness self-sharpening trepanning drill for small hole machining of ceramic matrix composite materials according to claim 1, wherein the first-grain-size diamond abrasive grain size = hole diameter to be machined-diameter of outer circular surface of matrix skeleton of cutter-thickness of brazing layer, and the first-grain-size diamond abrasive grain size < the second-grain-size diamond abrasive grain size is less than or equal to (first-grain-size diamond abrasive grain size + groove structure depth).

Description

High-sharpness strong self-sharpening trepanning drill for ceramic matrix composite small hole machining Technical Field The invention provides a high-sharpness self-sharpening trepanning drill for small hole processing of a ceramic matrix composite material, and belongs to the technical field of drilling processing. Background The ceramic matrix composite material has the characteristics of high strength, low density, high temperature resistance, corrosion resistance and the like, and has high brittleness, high hardness and anisotropism in the fields of aerospace, automobiles, new energy and the like to be widely applied （[1] M'Saoubi R, AxinteD, Soo SL, Nobel C, Attia H, Kappmeyer G, et al. High performance cutting ofadvanced aerospace alloys and composite materials. CIRP annals. 2015;64(2):557-80. [2]Li L. Synergistic effects of interface slip and fiber fracture on stress-dependent mechanical hysteresis of SiC/SiC minicomposites. Compositeinterfaces. 2020;27(10):937-51）. because the matrix and the fiber reinforced phase of the ceramic matrix composite material have the characteristics of high brittleness, high hardness and anisotropism, and the problems ([3]Hrechuk A, Bushlya V, M'Saoubi R, et al. Experimental investigations into tool wear of drilling CFRP. Procedia Manuf 2018; 25: 294–301. 24. [4]Jia Z, Bai Y, Wang F, et al. Effect of tool wear on drilling unidirectional CFRP laminatesin different fiber cutting angles. Int J Adv Manuf Technol 2020; 110: 89–99. 25. [5]Zhang B, Sui T, Lin B, et al. Drilling process of Cf/SiC ceramic matrix composites: Cutting force modeling, ma-chiningquality and PCD tool wear analysis. J Mater Process Technol 2022; 304: 117566.), that the abrasion of a trepanning drill is fast, the surface quality of the processed material is poor, the tearing of a hole outlet is serious and the like easily occur in the processing process of the traditional drilling processing cutters such as hard alloy and PCD cutters can not meet the processing requirements of high quality and low cost of the ceramic matrix composite material small holes. The brazing diamond trepanning drilling tool has the advantages of large abrasive particle exposure height, large chip containing space, strong wear resistance and the like, can overcome the defect of rapid wear of the trepanning drill when drilling the ceramic matrix composite material, and is widely applied to drilling processing of the ceramic matrix composite material. The drilling capability of the brazing diamond trepanning drill mainly depends on diamond abrasive particles attached to the surface of a substrate, the sum of the diamond abrasive particles, the diameter of the excircle of the substrate and the thickness of solder is the bore diameter of the drill, the size of the substrate cannot be too small due to the limitation of the rigidity of a cutter in the small bore processing, and the abrasive particles attached to the surface of the substrate can only be selected to be small in size so as to ensure the drilling precision. Therefore, in the drilling process, after the abrasive particles at the top end are worn and removed, the wall thickness of the trepanning drill is always free of the abrasive particles in the rotating process, and friction is always carried out between the trepanning drill and the material, so that the trepanning drill is in sudden failure. The small hole processing trepanning drill with the traditional structure has the advantages of low service life and poor processing quality, and cannot meet the small hole processing requirement of the ceramic matrix composite material. CN207432521U relates to a trepanning drill bit for a sapphire stick, and discloses a trepanning drill with a similar grooving structure, the grooving structure of the trepanning drill mainly aims at the problem of poor chip removal capability in processing, chip removal drainage capability of the trepanning drill is improved through grooving, and the trepanning drill bit is used for sleeving sapphire out of a crystal column by using the trepanning drill bit, so that a sapphire column is formed. Disclosure of Invention Aiming at the problems of poor processing quality and low service life of a cutter of a ceramic matrix composite material small hole, the invention provides the high-sharpness and high-strength self-sharpening trepanning drill for processing the ceramic matrix composite material small hole, which can obviously improve the drilling quality. The cross section area of the cutter matrix skeleton is reduced by arranging the groove-shaped structure on the inner and outer circular surfaces of the working end of the trepanning drill, the effective abrasive particle number on the cross section of the trepanning drill can be increased while the integral rigidity of the trepanning drill is ensured, so that the trepanning drill has the characteristics of strong self-sharpening and high sharpness, and the cutting capability of the trepanning dril