CN102728880B - Cutter shaft control method of leading line yielding track in blade helical milling process - Google Patents

Abstract

The invention provides a cutter shaft control method of a leading line yielding track in a blade helical milling process, comprising the following steps of: firstly, configuring a blade cylinder auxiliary face; secondly, taking a containing cylindrical face as an auxiliary face and constructing a leading line yielding curve; and finally, taking an outer normal vector of the cylindrical face as auxiliary information of vector interpolation of a cutter shaft of a leading line yielding track line, so as to obtain the cutter shaft vector of the leading line yielding track. The method disclosed by the invention has commonality and is suitable for spiral machining of a blade body of any blade; and the leading line yielding curve and the cutter shaft vector of a cutter site on the yielding curve can be effectively generated. Actual production verifies that the cutter shaft vector generated by the method is stable and smooth, the machining quality and the machining efficiency of the blade are improved and the service life of a machine tool and a tool is prolonged.

Description

In blade screw milling process, edge head is dodged the cutter shaft control method of track

Technical field

The present invention relates to blade mechanism processing technique field, be specially edge head in a kind of blade screw milling process and dodge the cutter shaft control method of track.

Background technology

Complex-shaped, the work under bad environment of engine blade, especially blade of aviation engine, require it must have accurate size, shape and strict surface integrity accurately, conventionally adopts multi-axis NC milling processing technology to be shaped.The milling mode adopting in the numerical control processing technology of blade has a milling, side milling method and spiral milling.Because helical milling has, clamping times is few, Cutting trajectory continuous, working (machining) efficiency advantages of higher, is subject to industry common concern.But, edge head is the topmost influence area of blade screw milling crudy, so the processing of blade front and rear edge curved surface is all to adopt the method for reserved certain surplus to avoid cutting, in addition due to add man-hour cutter location relatively intensive, under cutting state, cutter shaft corner is excessive, deal with very difficultly, be easy to cause and cut.For such problem, the blade high-quality and high-efficiency helical milling processing method that a kind of band edge head is dodged has been proposed in prior art, utilize cubic nonratio-nal B-spline curve to provide the building method of dodging curve.The generating tool axis vector that this method is dodged geometric locus for edge head is all to adopt the cutter location generating tool axis vector of blade Cutting trajectory line two-end-point to carry out interpolation acquisition; yet these two generating tool axis vector angles differ larger; even reach 180 °; now interpolation often occurs that generating tool axis vector is uncertain; need more information just can guarantee to obtain stable generating tool axis vector, thereby blade screw processing is normally carried out.

Summary of the invention

The technical problem solving

The problem existing for solving prior art, the present invention proposes edge head in a kind of blade screw milling process and dodges the cutter shaft control method of track, relates to that blade contains cylinder design, edge head is dodged Curve Design and dodges the problems such as track cutter shaft generation.

Technical scheme

This method is according to the physical dimension of blade, the containing face of cylinder of design blade, will contain the face of cylinder as secondary surface, and structure edge head is dodged curve, and utilize the outer method on the face of cylinder to vow the supplementary of dodging trajectory generating tool axis vector interpolation as edge head, obtain edge head and dodge track generating tool axis vector.

Technical scheme of the present invention is:

In described a kind of blade screw milling process, edge head is dodged the cutter shaft control method of track, it is characterized in that: comprise the following steps:

Step 1: structure blade cylinder secondary surface:

The blade curved surface of processed blade is parametric surface, and blade profile line is that v is to curve;

Step 1.1: the curve C of getting v=0.0 in leaf pelvic curvature face ₁curve C with v=0.0 in blade back curved surface ₂, some a (x _a, y _a, z _a), c (x _c, y _c, z _c), e (x _e, y _e, z _e) be curve C ₁two end points and mid point, some b (x _b, y _b, z _b), d (x _d, y _d, z _d), f (x _f, y _f, z _f) be curve C ₂two end points and mid point, the initial tip circle center of circle that obtains cylinder secondary surface is O _u(x _u, y _u, z _u):

$\left[\begin{array}{c}{x}_u\\ y_u\\ z_u\end{array}\right]=\frac{1}{6}\·\left[\begin{array}{c}{x}_a+x_b{+x}_c+x_d+x_e+x_f\\ y_a+y_b+y_c+y_d+y_e+y_f\\ z_a+z_b+z_c+z_d+z_e{+z}_f\end{array}\right]$

Get the curve C of v=1.0 in leaf pelvic curvature face ₃curve C with v=1.0 in blade back curved surface ₄, some α (x _α, y _α, z _α), φ (x _φ, y _φ, z _φ), γ (x _γ, y _γ, z _γ) be curve C ₃two end points and mid point, some β (x _β, y _β, z _β), η (x _η, y _η, z _η) be curve C ₄two end points and mid point, the round heart in the initial end that obtains cylinder secondary surface is O _l(x _l, y _l, z _l):

Step 1.2: the radius R of cylinder secondary surface _cfor R _c=d _max+ ε R, wherein d _maxfor edge head region is to the ultimate range of cylinder secondary surface axial line, R is tool radius, and ε prevents cutter when dodging and the bump adjustment coefficient of interference of blade edge head region; Cylinder secondary surface axial line is O _uo _lline;

Step 1.3: by curve C ₁, C ₂, C ₃, C ₄two ends end points project on cylinder secondary surface axial line, obtain in eight subpoints two the longest some A of distance between any two ₁and A ₂; To put A ₁and A ₂along cylinder secondary surface axial line, move laterally respectively the distance that is not less than R, obtain the final tip circle center of circle O ' of cylinder secondary surface _uwith the round heart O ' in the final end _l;

Step 2: structure edge head is dodged curve:

P ' ₀, P ₀penultimate cutter location and last cutter location for the Path line on blade one N-Side surf; P ₉, P ' ₉first cutter location and second cutter location for next the Path line on blade opposite side curved surface;

Step 2.1: along P ' ₀p ₀tangential direction be take radius as r ₁structure central angle is the minor arc P of 30 ° ~ 45 ° ₀p ₁, minor arc P ₀p ₁towards blade curved surface outside, r ₁for circular arc withdrawing radius; Along P ' ₉p ₉tangential direction be take radius as r ₂structure central angle is the minor arc P of 30 ° ~ 45 ° ₉p ₈, minor arc P ₉p ₈towards blade curved surface outside, r ₂for circular arc feed radius;

Step 2.2: along P ₁the tangential direction straight line of some place circular arc extends, and obtains straightway P ₁p ₃, P ₃for extending the intersection point of straight line and cylinder secondary surface; Along P ₈the tangential direction straight line of some place circular arc extends, and obtains straightway P ₈p ₆, P ₆for extending the intersection point of straight line and cylinder secondary surface;

Step 2.3: get a P on cylinder secondary surface ₃and P ₆between the shortest curved section P of arc length ₃p ₆;

Step 2.4: at straightway P ₁p ₃on get a P ₂, at curved section P ₃p ₆on get a P ₄, line segment P ₂p ₃length equal curve P ₃p ₄arc length; At straightway P ₈p ₆on get a P ₇, at curved section P ₃p ₆on get a P ₅, line segment P ₆p ₇length equal curve P ₅p ₆arc length; Point P ₃, P ₄, P ₅and P ₆for curved section P ₃p ₆on four points successively;

Step 2.5: with a P ₂, P ₃and P ₄structure SPL P ₂p ₄, SPL P ₂p ₄with straightway P ₁p ₃with curved section P ₄p ₅tangent; With a P ₅, P ₆and P ₇structure SPL P ₅p ₇, SPL P ₅p ₇with straightway P ₈p ₆with curved section P ₄p ₅tangent;

Connect successively minor arc P ₀p ₁, straightway P ₁p ₂, SPL P ₂p ₄, curved section P ₄p ₅, SPL P ₅p ₇, straightway P ₇p ₈with minor arc P ₈p ₉obtain constructing edge head and dodge curve;

Step 3: generate edge head and dodge curve cutter location:

Step 3.1: even discrete curve section P ₄p ₅, obtain curved section P ₄p ₅on point of a knife point; With curved section P ₄p ₅the outer direction of normal of upper each point of a knife point on cylinder secondary surface, as the generating tool axis vector of each point of a knife point, obtains curved section P ₄p ₅cutter location;

Step 3.2: segmentation discrete curve group P ₀p ₁p ₂p ₄, obtain curve group P ₀p ₁p ₂p ₄on point of a knife point set Q={Q _i| i=0 ..., N}, wherein Q _owith P ₀overlap, Q _nwith P ₄overlap;

Step 3.3: adopt quaternion interpolation to obtain Q={Q _i| i=1 ..., the generating tool axis vector at N-1} point place:

Step 3.3.1: calculate P ₀p ₁p ₂p ₄the overall length ts of curved section:

$\mathrm{ts}=\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}\left|Q_k{Q}_{k+1}\right|$

Wherein | Q _kq _k+1| represent some Q _kand Q _k+1between the length of line segment;

Step 3.3.2: calculate from starting point Q _oto Q _ipath length ds _i:

${\mathrm{ds}}_i=\underset{k=0}{\overset{i-1}{\mathrm{\Σ}}}\left|Q_k{Q}_{k+1}\right|$

Step 3.3.3:Q={Q _i| i=1 ..., in N-1}, the generating tool axis vector of each point is:

$v_i=\frac{\sin (1-t_i)\mathrm{\θ}}{\sin \mathrm{\θ}}{v}_0+\frac{\sin t_i\mathrm{\θ}}{\sin \mathrm{\θ}}{v}_4.(i=1,\·\·\·,N-1)$

T wherein _i=ds _i/ ts, v ₀for P ₀the unit generating tool axis vector at some place, v ₄for the P obtaining in step 3.1 ₄the unit generating tool axis vector at some place, θ=arccos (v ₀v ₄);

Step 3.4: determine curve group P according to step 3.2 to the method in step 3.3 ₅p ₇p ₈p ₉cutter location.

In described a kind of blade screw milling process, edge head is dodged the cutter shaft control method of track, it is characterized in that: line segment P ₆p ₇length the line is busy section a P ₆p ₈the ratio of length and line segment P ₂p ₃the line is busy section a P ₁p ₃the ratio of length is identical, is 5% ~ 30%.

In described a kind of blade screw milling process, edge head is dodged the cutter shaft control method of track, it is characterized in that: curve group P ₀p ₁p ₂p ₄it is curve group P that upper slitter cusp is concentrated the arc length of adjacent point of a knife point ₀p ₁p ₂p ₄5% of path length; Curve group P ₅p ₇p ₈p ₉it is curve group P that upper slitter cusp is concentrated the arc length of adjacent point of a knife point ₅p ₇p ₈p ₉5% of path length.

Beneficial effect

The method that the present invention proposes has versatility, is suitable for the situation of any blade blade spiral processing, can effectively generate the generating tool axis vector that edge head is dodged curve and dodged cutter location on geometric locus.Through actual production checking, the generating tool axis vector light stable that the method generates is suitable, has improved crudy and the working (machining) efficiency of blade, has extended the service life of lathe and cutter.

Accompanying drawing explanation

Fig. 1: schematic diagram is calculated in the initial tip circle center of circle;

Fig. 2: blade cylinder secondary surface organigram;

Fig. 3: edge head is dodged curve construction schematic diagram;

Fig. 4: dodge curve cutter location generating tool axis vector in embodiment and distribute;

Fig. 5: generating tool axis vector variable angle in embodiment.

Wherein: 1, rafter plate; 2, blade curved surface.

The specific embodiment

Below in conjunction with specific embodiment, the present invention is described:

The present embodiment is processed as example with five axle endless knife of aero-engine model blade, calculates the cutter location track of blade curved surface area according to second order Taylor approximate algorithm, and wherein, endless knife radius R is 8mm.

The cutter shaft control method that in the present embodiment, edge head is dodged track comprises the following steps:

Step 1: structure blade cylinder secondary surface:

It is to realize the instrument that edge head is dodged curve that blade contains cylinder secondary surface, determines that face of cylinder key is the tip circle center of circle, the round heart in the end and cylindrical radius, as shown in Figure 1.The blade curved surface of processed blade (leaf pelvic curvature face, blade back curved surface) is parametric surface, and blade profile line is that v is to curve; The limit parameter at blade tip place is v=0.0.

Step 1.1: the curve C of getting v=0.0 in leaf pelvic curvature face ₁curve C with v=0.0 in blade back curved surface ₂, some a (x _a, y _a, z _a), c (x _c, y _c, z _c), e (x _e, y _e, z _e) be curve C ₁two end points and mid point, some b (x _b, y _b, z _b), d (x _d, y _d, z _d), f (x _f, y _f, z _f) be curve C ₂two end points and mid point, the initial tip circle center of circle that obtains cylinder secondary surface is O _u(x _u, y _u, z _u):

$\left[\begin{array}{c}{x}_u\\ y_u\\ z_u\end{array}\right]=\frac{1}{6}\·\left[\begin{array}{c}{x}_a+x_b{+x}_c+x_d+x_e+x_f\\ y_a+y_b+y_c+y_d+y_e+y_f\\ z_a+z_b+z_c+z_d+z_e{+z}_f\end{array}\right]$

Get the curve C of v=1.0 in leaf pelvic curvature face ₃curve C with v=1.0 in blade back curved surface ₄, some α (x _α, y _α, z _α), φ (x _φ, y _φ, z _φ), γ (x _γ, y _γ, z _γ) be curve C ₃two end points and mid point, some β (x _β, y _β, z _β),

η (x _η, y _η, z _η) be curve C ₄two end points and mid point, the round heart in the initial end that obtains cylinder secondary surface is Ol (x _l, y _l, z _l):

Step 1.2: the radius R of cylinder secondary surface _cfor R _c=d _max+ ε R, wherein d _maxfor edge head region is to the ultimate range of cylinder secondary surface axial line, R is tool radius, and ε prevents cutter when dodging and the bump adjustment coefficient of interference of blade edge head region; Cylinder secondary surface axial line is O _uo _lline;

Step 1.3: by curve C ₁, C ₂, C ₃, C ₄two ends end points project on cylinder secondary surface axial line, obtain in eight subpoints two the longest some A of distance between any two ₁and A ₂; To put A ₁and A ₂along cylinder secondary surface axial line, move laterally respectively the distance that is not less than R, obtain the final tip circle center of circle O ' of cylinder secondary surface _uwith the round heart O ' in the final end _l; As shown in Figure 2.

Step 2: structure edge head is dodged curve:

Edge head is dodged curve through cutting out blade curved surface, idle stroke, three processes of incision blade opposite side curved surface.This method is dodged curve by edge head and is divided into seven sections of trajectories, as shown in Figure 3.

P ' ₀, P ₀penultimate cutter location and last cutter location for the Path line on blade one N-Side surf; P ₉, P ' ₉first cutter location and second cutter location for next the Path line on blade opposite side curved surface;

Step 2.1: along P _o' P _otangential direction be take radius as r ₁structure central angle is the minor arc P of 30 ° ~ 45 ° ₀p ₁, minor arc P ₀p ₁towards blade curved surface outside, r ₁for circular arc withdrawing radius; Along P ₉' P ₉tangential direction be take radius as r ₂structure central angle is the minor arc P of 30 ° ~ 45 ° ₉p ₈, minor arc P ₉p ₈towards blade curved surface outside, r ₂for circular arc feed radius;

Step 2.2: along P ₁the tangential direction straight line of some place circular arc extends, and obtains straightway P ₁p ₃, P ₃for extending the intersection point of straight line and cylinder secondary surface; Along P ₈the tangential direction straight line of some place circular arc extends, and obtains straightway P ₈p ₆, P ₆for extending the intersection point of straight line and cylinder secondary surface;

Step 2.3: get a P on cylinder secondary surface ₃and P ₆between the shortest curved section P of arc length ₃p ₆;

Step 2.4: at straightway P ₁p ₃on get a P ₂, at curved section P ₃p ₆on get a P ₄, line segment P ₂p ₃length equal curve P ₃p ₄arc length; At straightway P ₈p ₆on get a P ₇, at curved section P ₃p ₆on get a P ₅, line segment P ₆p ₇length equal curve P ₅p ₆arc length; Point P ₃, P ₄, P ₅and P ₆for curved section P ₃p ₆on four points successively;

Line segment P ₆p ₇length the line is busy section a P ₆p ₈the ratio of length and line segment P ₂p ₃the line is busy section a P ₁p ₃the ratio of length is identical, is 5% ~ 30%, gets 5% in the present embodiment;

Step 2.5: with a P ₂, P ₃and P ₄structure SPL P ₂p ₄, SPL P ₂p ₄with straightway P ₁p ₃with curved section P ₄p ₅tangent; With a P ₅, P ₆and P ₇structure SPL P ₅p ₇, SPL P ₅p ₇with straightway P ₈p ₆with curved section P ₄p ₅tangent;

Connect successively minor arc P ₀p ₁, straightway P ₁p ₂, SPL P ₂p ₄, curved section P ₄p ₅, SPL P ₅p ₇, straightway P ₇p ₈with minor arc P ₈p ₉obtain constructing edge head and dodge curve;

Step 3: generate edge head and dodge curve cutter location:

Step 3.1:P ₄p ₅curved section is to be positioned on cylinder secondary surface, evenly discrete curve section P ₄p ₅, obtain curved section P ₄p ₅on point of a knife point; With curved section P ₄p ₅the outer direction of normal of upper each point of a knife point on cylinder secondary surface, as the generating tool axis vector of each point of a knife point, obtains curved section P ₄p ₅cutter location, realize the generating tool axis vector smooth change on cylinder secondary surface;

Step 3.2: segmentation discrete curve group P ₀p ₁p ₂p ₄, obtain curve group P ₀p ₁p ₂p ₄on point of a knife point set Q={Q _i| i=0 ..., N}, wherein Q _owith P ₀overlap, Q _nwith P ₄overlap; In the present embodiment, get curve group P ₀p ₁p ₂p ₄it is curve group P that upper slitter cusp is concentrated the arc length of adjacent point of a knife point ₀p ₁p ₂p ₄5% of path length, to guarantee at P ₀point is to P ₄in point curve section, cutter shaft evenly slowly changes;

Step 3.3: adopt quaternion interpolation to obtain Q={Q _i| i=1 ..., the generating tool axis vector at N-1} point place:

Step 3.3.1: calculate P ₀p ₁p ₂p ₄the overall length ts of curved section:

$\mathrm{ts}=\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\left|Q_k{\mathrm{<figure-callout\; id="1"\; label="Q\; k\; +"\; filenames="HDA00001877770200011.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{k+}\right|$

Wherein | Q _kq _k+1| represent some Q _kand Q _k+1between the length of line segment;

Step 3.3.2: calculate from starting point Q _oto Q _ipath length ds _i:

${\mathrm{ds}}_i=\underset{k=0}{\overset{i-1}{\mathrm{\&Sigma;}}}\left|Q_k{\mathrm{<figure-callout\; id="1"\; label="Q\; k\; +"\; filenames="HDA00001877770200011.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{k+}\right|$

Step 3.3.3:Q={Q _i| i=1 ..., in N-1}, the generating tool axis vector of each point is:

$v_i=\frac{\sin (1-t_i)\mathrm{\&theta;}}{\sin \mathrm{\&theta;}}{v}_0+\frac{\sin t_i\mathrm{\&theta;}}{\sin \mathrm{\&theta;}}{v}_4.(i=1,\&CenterDot;\&CenterDot;\&CenterDot;,N-1)$

T wherein _i=ds _i/ s, v ₀for P ₀the unit generating tool axis vector at some place, due to P ₀point is last cutter location of blade one N-Side surf, so its unit generating tool axis vector is known, and v ₄for the P obtaining in step 3.1 ₄the unit generating tool axis vector at some place, θ=arccos (v ₀v ₄);

Step 3.4: determine curve group P according to step 3.2 to the method in step 3.3 ₅p ₇p ₈p ₉cutter location:

Segmentation discrete curve group P ₅p ₇p ₈p ₉, obtain curve group P ₅p ₇p ₈p ₉on point of a knife point set U={U _i| i=0 ..., M}, wherein U ₀with P ₉overlap, U _mwith P ₅overlap; In the present embodiment, get curve group P ₅p ₇p ₈p ₉it is curve group P that upper slitter cusp is concentrated the arc length of adjacent point of a knife point ₅p ₇p ₈p ₉5% of path length, to guarantee at P ₉point is to P ₅in point curve section, cutter shaft evenly slowly changes;

Adopt quaternion interpolation to obtain U={U _i| i=1 ..., the generating tool axis vector at M-1} point place:

Step 3.4.1: calculate P ₅p ₇p ₈p ₉the overall length ks of curved section:

$\mathrm{ks}=\underset{k=0}{\overset{M-1}{\mathrm{\&Sigma;}}}\left|U_k{U}_{k+1}\right|$

Wherein | U _ku _k+1| represent some U _kand U _k+1between the length of line segment;

Step 3.4.2: calculate from starting point U ₀path length ls to Ui _i:

${\mathrm{ls}}_i=\underset{k=0}{\overset{i-1}{\mathrm{\&Sigma;}}}\left|U_k{U}_{k+1}\right|$

Step 3.4.3:U={U _i| i=1 ..., in M-1}, the generating tool axis vector of each point is:

$v_i=\frac{\sin (1-o_i)\mathrm{\&theta;}}{\sin \mathrm{\&theta;}}{v}_9+\frac{\sin o_i\mathrm{\&theta;}}{\sin \mathrm{\&theta;}}{v}_5,(i=1\&CenterDot;\&CenterDot;\&CenterDot;,M-1)$

O wherein _i=ls _i/ ks, v ₉for P ₉the unit generating tool axis vector at some place, due to P ₉point is first cutter location of blade opposite side curved surface, so its unit generating tool axis vector is known, and v ₅for the P obtaining in step 3.1 ₅the unit generating tool axis vector at some place,

$\mathrm{\&theta;}=\arccos (v_9\&CenterDot;v_5).$

Obtain thus edge head and dodge the cutter location of curve, the adjacent Path line being chosen in the present embodiment on blade Surface Parameters v=0.3 curve is analyzed, it dodges curve cutter location and the projection of generating tool axis vector on XOY plane as shown in Figure 4, the two-end-point generating tool axis vector angle that edge head is dodged trajectory is 177.8 °, and the generating tool axis vector variable angle that edge head is dodged curve as shown in Figure 5.

Claims (3)

1. in blade screw milling process, edge head is dodged a cutter shaft control method for track, it is characterized in that: comprise the following steps:

Step 1: structure blade cylinder secondary surface:

The blade curved surface of processed blade is parametric surface, blade profile line be v to curve, the limit parameter at blade tip place is v=0.0;

Step 1.1: the curve C of getting v=0.0 in leaf pelvic curvature face ₁curve C with v=0.0 in blade back curved surface ₂, some a (x _a, y _a, z _a), c (x _c, y _c, z _c), e (x _e, y _e, z _e) be curve C ₁two end points and mid point, some b (x _b, y _b, z _b), d (x _d, y _d, z _d), f (x _f, y _f, z _f) be curve C ₂two end points and mid point, the initial tip circle center of circle that obtains cylinder secondary surface is O _u(x _u, y _u, z _u):

$\left[\begin{array}{c}{x}_u\\ y_u\\ z_u\end{array}\right]=\frac{1}{6}\&CenterDot;\left[\begin{array}{c}{x}_a+x_b+x_c+x_d+x_e+x_f\\ y_a+y_b+y_c+y_d+y_e+y_f\\ z_a+z_b+z_c+z_d+z_e+z_f\end{array}\right]$

Get the curve C of v=1.0 in leaf pelvic curvature face ₃curve C with v=1.0 in blade back curved surface ₄, some α (x _α, y _α, z _α), φ (x _φ, y _φ, z _φ), γ (x _γ, y _γ, z _γ) be curve C ₃two end points and mid point, some β (x _β, y _β, z _β),

η (x _η, y _η, z _η) be curve C ₄two end points and mid point, the round heart in the initial end that obtains cylinder secondary surface is O _l(x _l, y _l, z _l):

Step 1.2: the radius R of cylinder secondary surface _cfor R _c=d _max+ ε R, wherein d _maxfor edge head region is to the ultimate range of cylinder secondary surface axial line, R is tool radius, and ε prevents cutter when dodging and the bump adjustment coefficient of interference of blade edge head region; Cylinder secondary surface axial line is O _uo _lline;

Step 1.3: by curve C ₁, C ₂, C ₃, C ₄two ends end points project on cylinder secondary surface axial line, obtain in eight subpoints two the longest some A of distance between any two ₁and A ₂; To put A ₁and A ₂along cylinder secondary surface axial line, move laterally respectively the distance that is not less than R, obtain the final tip circle center of circle O ' of cylinder secondary surface _uwith the round heart O ' in the final end _l;

Step 2: structure edge head is dodged curve:

P ' ₀, P ₀penultimate cutter location and last cutter location for the Path line on blade one N-Side surf; P ₉, P ' ₉first cutter location and second cutter location for next the Path line on blade opposite side curved surface;

Step 2.1: along P ' ₀p ₀tangential direction be take radius as r ₁structure central angle is the minor arc P of 30 °～45 ° ₀p ₁, minor arc P ₀p ₁towards blade curved surface outside, r ₁for circular arc withdrawing radius; Along P ' ₉p ₉tangential direction be take radius as r ₂structure central angle is the minor arc P of 30 °～45 ° ₉p ₈, minor arc P ₉p ₈towards blade curved surface outside, r ₂for circular arc feed radius;

Step 2.2: along P ₁the tangential direction straight line of some place circular arc extends, and obtains straightway P ₁p ₃, P ₃for extending the intersection point of straight line and cylinder secondary surface; Along P ₈the tangential direction straight line of some place circular arc extends, and obtains straightway P ₈p ₆, P ₆for extending the intersection point of straight line and cylinder secondary surface;

Step 2.3: get a P on cylinder secondary surface ₃and P ₆between the shortest curved section P of arc length ₃p ₆;

Step 2.4: at straightway P ₁p ₃on get a P ₂, at curved section P ₃p ₆on get a P ₄, line segment P ₂p ₃length equal curve P ₃p ₄arc length; At straightway P ₈p ₆on get a P ₇, at curved section P ₃p ₆on get a P ₅, line segment P ₆p ₇length equal curve P ₅p ₆arc length; Point P ₃, P ₄, P ₅and P ₆for curved section P ₃p ₆on four points successively;

Step 2.5: with a P ₂, P ₃and P ₄structure SPL P ₂p ₄, SPL P ₂p ₄with straightway P ₁p ₃with curved section P ₄p ₅tangent; With a P ₅, P ₆and P ₇structure SPL P ₅p ₇, SPL P ₅p ₇with straightway P ₈p ₆with curved section P ₄p ₅tangent;

Connect successively minor arc P ₀p ₁, straightway P ₁p ₂, SPL P ₂p ₄, curved section P ₄p ₅, SPL P ₅p ₇, straightway P ₇p ₈with minor arc P ₈p ₉obtain constructing edge head and dodge curve;

Step 3: generate edge head and dodge curve cutter location:

Step 3.1: even discrete curve section P ₄p ₅, obtain curved section P ₄p ₅on point of a knife point; With curved section P ₄p ₅the outer direction of normal of upper each point of a knife point on cylinder secondary surface, as the generating tool axis vector of each point of a knife point, obtains curved section P ₄p ₅cutter location;

Step 3.2: segmentation discrete curve group P ₀p ₁p ₂p ₄, obtain curve group P ₀p ₁p ₂p ₄on point of a knife point set Q={Q _i| i=0 ..., N}, wherein Q ₀with P ₀overlap, Q _nwith P ₄overlap;

Step 3.3: adopt quaternion interpolation to obtain Q={Q _i| i=1 ..., the generating tool axis vector at N-1} point place:

Step 3.3.1: calculate P ₀p ₁p ₂p ₄the overall length ts of curved section:

$\mathrm{ts}=\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}\left|Q_k{Q}_{k+1}\right|$

Wherein | Q _kq _k+1| represent some Q _kand Q _k+1between the length of line segment;

Step 3.3.2: calculate from starting point Q ₀to Q _ipath length ds _i:

${\mathrm{ds}}_i=\underset{k=0}{\overset{i-1}{\mathrm{\&Sigma;}}}\left|Q_k{Q}_{k+1}\right|$

Step 3.3.3:Q={Q _i| i=1 ..., in N-1}, the generating tool axis vector of each point is:

$v_i=\frac{\sin (1-t_i)\mathrm{\&theta;}}{\sin \mathrm{\&theta;}}{v}_0+\frac{\sin t_i\mathrm{\&theta;}}{\sin \mathrm{\&theta;}}{v}_4,(i=1,...,N-1)$

T wherein _i=ds _its, v ₀for P ₀the unit generating tool axis vector at some place, v ₄for the P obtaining in step 3.1 ₄the unit generating tool axis vector at some place, θ=arccos (v ₀v ₄);

Step 3.4: determine curve group P according to step 3.2 to the method in step 3.3 ₅p ₇p ₈p ₉cutter location.

2. edge head is dodged the cutter shaft control method of track in a kind of blade screw milling process according to claim 1, it is characterized in that: line segment P ₆p ₇length the line is busy section a P ₆p ₈the ratio of length and line segment P ₂p ₃the line is busy section a P ₁p ₃the ratio of length is identical, is 5%～30%.

3. according to edge head in a kind of blade screw milling process described in claim 1 or 2, dodge the cutter shaft control method of track, it is characterized in that: curve group P ₀p ₁p ₂p ₄it is curve group P that upper slitter cusp is concentrated the arc length of adjacent point of a knife point ₀p ₁p ₂p ₄5% of path length; Curve group P ₅p ₇p ₈p ₉it is curve group P that upper slitter cusp is concentrated the arc length of adjacent point of a knife point ₅p ₇p ₈p ₉5% of path length.

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