CN-122007808-A - High-precision numerical control machining method for bottom of blind hole

CN122007808ACN 122007808 ACN122007808 ACN 122007808ACN-122007808-A

Abstract

The application belongs to the technical field of numerical control machining, and particularly relates to a high-precision numerical control machining method for the bottom of a blind hole; the method comprises the steps of obtaining the Z-directional height of the residual angle of the blind hole and the effective machining depth of the boring cutter according to the parameters of the blind hole, obtaining the front aperture allowance of the boring cutter and the primary hole diameter of the blind hole according to the parameters of the boring cutter, determining the radial adjustment range of the boring cutter according to the primary hole diameter of the blind hole, the bottom angle of the end mill and the aperture of the blind hole, creating a residual curved surface of the bottom angle of the blind hole according to the front aperture allowance of the boring cutter, the Z-directional height of the blind hole and the bottom angle of the blind hole, machining the primary hole of the blind hole by using the end mill after the Z-directional height of the end mill is checked, machining the aperture of the blind hole by using the boring cutter after the Z-directional height of the boring cutter is checked, adjusting the boring cutter to the minimum diameter, and cutting the residual of the bottom angle of the blind hole according to the residual curved surface, so that the bottom of the boring cutter has no machining step residues, and solves the residual problems of machining steps formed after the boring cutter and the end mill.

Inventors

QIU YANG
TANG DAN
ZHANG TINGYU
CHEN YAO
XUE ZHAO
DU WENJUN
TANG LIN
XIONG HANG
ZHOU WENCHANG
ZHANG XICHENG

Assignees

成都飞机工业（集团）有限责任公司

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (10)

1. The high-precision numerical control processing method for the bottom of the blind hole is characterized by comprising the following specific method steps of: s1, acquiring the residual Z-direction height of a blind hole bottom angle and the effective depth of boring cutter processing according to blind hole parameters; S2, obtaining the hole diameter allowance before boring and the primary hole diameter of the blind hole according to boring cutter parameters; s3, determining the radial adjustment range of the boring cutter according to the primary hole diameter of the blind hole, the bottom angle of the end mill and the aperture of the blind hole in the parameters of the blind hole; S4, creating a residual curved surface of the blind hole bottom angle according to the hole diameter allowance before boring, the blind hole bottom angle residual Z-direction height and the blind hole bottom angle in the blind hole parameters; s5, after checking the Z-direction height of the end mill, processing the primary hole of the blind hole by using the end mill according to the primary hole diameter of the blind hole; s6, after checking the Z-direction height of the boring cutter, machining the aperture of the blind hole by using the boring cutter according to the effective machining depth of the boring cutter; And S7, adjusting the boring cutter to the minimum diameter, and performing line cutting processing on the bottom corner residues of the blind holes according to the residual curved surface, so that the bottoms of the boring holes have no processing step residues.
2. The method for numerical control machining of the bottom of a high-precision blind hole according to claim 1, wherein the blind hole parameters further comprise blind hole depth.
3. The method for numerical control machining of the bottom of the blind hole with high precision according to claim 2, wherein the effective depth of the boring cutter machining and the residual Z-direction height of the bottom angle of the blind hole are calculated through the bottom angle of the blind hole and the depth of the blind hole.
4. The method for numerical control machining of the bottom of the blind hole with high precision according to claim 3, wherein the specific calculation formula of the residual Z-direction height of the bottom angle of the blind hole is as follows: h1=R+h3; wherein, the meaning of h1 is the residual Z-direction height of the bottom angle of the blind hole, and the meaning of h3 is the residual height h3 of the inner wall of the hole.
5. The high-precision numerical control machining method for the bottom of the blind hole, which is disclosed in claim 4, is characterized in that the effective depth of boring cutter machining is smaller than the depth of the blind hole minus the bottom angle of the blind hole, so that the height of a residual area on the inner wall of the hole is formed, the residual height of the inner wall of the hole is specifically obtained by subtracting the bottom angle of the blind hole from the depth of the blind hole and subtracting the effective depth of boring cutter machining from the blind hole, and the effective depth of boring cutter machining is calculated by the following formula: h2=h-R-h3; Wherein, h2 means the effective depth of boring cutter processing, h means the depth of a blind hole, R means the base angle of the blind hole, h3 means the height of the residual area of the inner wall of the hole, and the height h3 of the residual area of the inner wall of the hole is 0.1mm to 0.2mm.
6. The high-precision numerical control machining method for the bottom of the blind hole, which is disclosed in claim 5, is characterized in that the boring cutter parameters comprise boring cutter radial edge length, the pre-boring aperture allowance and the primary hole diameter of the blind hole in the step S2 are calculated by the boring cutter radial edge length, and the boring cutter radial edge length is 0.3mm to 0.5mm larger than the pre-boring aperture allowance, and the calculation formula is as follows: δ=L1-δ1; Wherein, delta means the hole diameter allowance before boring, L1 means the radial edge length of the boring cutter, and delta 1 means the value that the radial edge length of the boring cutter is larger than the hole diameter allowance before boring.
7. The method for numerical control machining of the bottom of the blind hole with high precision according to claim 6, wherein the calculation formula of the primary hole diameter of the blind hole in the step S2 is specifically as follows: D1=D-2×δ=D-2×(L1-δ1) ; Wherein D1 means the primary pore diameter of the blind hole, D means the pore diameter of the blind hole, and delta means the pore diameter allowance before boring.
8. The high-precision blind hole bottom numerical control machining method according to claim 7, wherein the boring cutter radial adjustment range in the step S3 is specifically that the maximum diameter of boring cutter adjustment is larger than the blind hole diameter, the minimum diameter of boring cutter adjustment is smaller than the initial hole diameter of the blind hole minus two times of the end mill base angle, the end mill base angle is larger than or equal to the blind hole diameter, and the specific relation of the minimum diameter of boring cutter adjustment is as follows: DL<D1-2×R1; in the formula, DL is the minimum diameter adjusted by a boring cutter, D1 is the primary hole diameter of a blind hole, and R1 is the base angle of an end mill.
9. The high-precision numerical control processing method for the bottom of the blind hole according to claim 8, wherein the residual curved surface of the bottom angle of the blind hole comprises the bottom angle of the blind hole, a residual area of the bottom of the blind hole and the height of a residual area of the inner wall of the hole, the residual area of the bottom of the blind hole is the residual radial length of the bottom angle of the blind hole, the residual radial length of the bottom angle of the blind hole is equal to the residual Z-direction height of the bottom angle of the blind hole, and the height of the residual area of the inner wall of the blind hole is equal to the residual Z-direction height of the bottom angle of the blind hole minus the bottom angle of the blind hole.
10. The numerical control machining method for the bottom of the blind hole with high precision according to claim 9, wherein the step S4 is characterized in that the residual curved surface of the bottom angle of the blind hole is created by adopting Isoparametric Machining operation, and the step S7 is characterized in that the step S7 is performed by calling the residual curved surface of the bottom angle of the blind hole and performing line cutting machining on the residual curved surface of the bottom angle of the blind hole by adopting Isoparametric Machining.

Description

High-precision numerical control machining method for bottom of blind hole Technical Field The application belongs to the technical field of numerical control machining, and particularly relates to a high-precision numerical control machining method for the bottom of a blind hole. Background Along with the continuous development of the aviation industry, the precision of the assembly connection in engineering is higher and higher, the fatigue strength requirement on the assembly connection part is higher and higher, the assembly connection area is often connected through various high-precision holes on the part, and the requirements on the hole position precision, the aperture precision and the surface quality of the inner wall surface of the hole of the high-precision hole of the assembly connection area of the part are higher and higher corresponding to engineering application. The high-precision blind hole is used as one of the assembly connecting holes, and is structurally characterized by comprising a high-precision blind hole inner wall, a high-precision blind hole bottom and a high-precision blind hole bottom angle R, as shown in figure 1, wherein the surface quality and the aperture precision of the inner wall of the hole are extremely high, the aperture precision is at least at IT8 level and IT8 level, and the surface quality roughness is at least at Ra1.6 and Ra1.6 level. In the numerical control machining process, materials and cutters are mutually extruded, elastic variables of the materials and the cutters are taken as important factors influencing machining precision, and the boring diameter can be adjusted according to actual elastic variables of different materials and different structures of a part, so that the influence of the elastic variables of the part and the boring cutter on the aperture in the machining process is reduced, and further high-precision machining of the inner wall of the hole is realized. The bottom and bottom angle R of the hole are usually formed by machining through a numerical control end mill, in order to ensure that the inner wall of the hole cannot be milled by the end mill, in numerical control programming of the bottom of the hole, smaller back chipping avoiding distances are generally required to be reserved on the inner wall of the hole and the bottom of the hole, machining step residues shown in fig. 2 are formed at the bottom of the high-precision blind hole after the high-precision blind hole is machined and formed, in engineering application, the machining step residues are easy to generate stress concentration, cracks are easy to occur in the repeated use process and influence the fatigue service life of a part, the machining step residues are required to be eliminated, grinding treatment is carried out by a bench worker by a similar conventional machining step residue means, because grinding is carried out in the hole, the operation space and a grinding tool are limited, firstly, grinding quality risks exist, secondly, the inner wall of the hole is easy to be bumped in the grinding process, the grinding space is limited, the operation of a bench worker is difficult, thirdly, the grinding tool is too small, the grinding tool can be carried out in the deep hole, and the grinding process, and fourthly, the surface quality is poor. Therefore, a numerical control machining method for the bottom of the high-precision blind hole is urgently needed in engineering application, so that the problem of residual machining steps left after numerical control machining of the high-precision blind hole is solved, and the surface quality of the high-precision blind hole is improved. For example, a Chinese patent with publication number CN109604942A and publication number 2019, 4-12, and with the name of "numerical control machining method for high-precision flat bottom hanging hole of aluminum alloy" is disclosed, which comprises the steps of (1) clamping parts, (2) machining primary holes, (21) determining that the diameter of the primary hole is phi F, and the diameter of the final hole is phi, and the diameters of the final hole and the primary hole meet phiThe method comprises the steps of S22, selecting a hole milling cutter as a hole milling cutter, performing hole milling, wherein the diameter R of a bottom tooth of the hole milling cutter is consistent with the diameter phi R of a bottom corner of the hole, the length-diameter ratio of the hole milling cutter is smaller than 4:1, S23, performing machining, namely performing down milling by adopting a spiral lower cutter, wherein the track diameter of the spiral lower cutter is larger than D/4, performing axial layering machining on a part, and the axial machining depth is required to meet the requirement that LG=LH, wherein D is the diameter of the hole milling cutter, LG is the axial machining depth of the hole, LH is the final hole depth, S3 is boring, and S4 is root bottom corner machining, so that the machini