A post-processing method for radial compensation of round hole machining

Abstract

A post-processing method for radial compensation of circular hole machining, comprising the following steps: obtaining three tool position points and a tool axis vector on a tool path trajectory of circular hole machining; obtaining a center reference point located on a center axis of the circular hole according to the three tool position points and the tool axis vector; obtaining a target tool position point on the tool path trajectory of the circular hole machining, and obtaining a radial compensation unit vector at the target tool position point according to the center reference point, the tool axis vector and the target tool position point; and obtaining a compensated tool position point after radial compensation according to the target tool position point, the radial compensation unit vector and a target compensation value.

Description

TECHNICAL FIELD

[0001] The application relates to a post-processing method for radial compensation of round hole machining, and belongs to the technical field of numerical control machining. BACKGROUND

[0002] In the mechanical machining process of a round hole, in order to accurately ensure the diameter precision after machining, the radial feed amount needs to be adjusted in the machining process to compensate for the hole diameter machining deviation caused by tool wear, tool setting and other factors. There are mainly three technical approaches at present.

[0003] Technical approach one: according to the measured value of the hole diameter, the numerical control machining tool path is corrected, and a numerical control machining program is regenerated to realize compensation machining.

[0004] Technical approach two: the radius compensation function of part of the numerical control machine tool system is used to realize radial compensation machining;

[0005] Technical approach three: the compensation amount is taken as an input parameter to post-process the pre-position tool file, generate a compensated numerical control machining program, and realize radial compensation machining.

[0006] The above three methods at least have the following shortcomings:

[0007] Technical approach one: the program lacks universality, the numerical control machining program needs to be corrected according to the actual machining result, the preparation time is long, and the production efficiency is low;

[0008] Technical approach two: due to the difference in types and versions of numerical control systems, not all numerical control equipment supports convenient radius compensation machining, so this method has the defect of being restricted by equipment;

[0009] Technical approach three: the existing post-processing method needs to be based on known tool position coordinates, tool axis vectors and tool contact point coordinates to complete the dynamic calculation of the compensation vector, but not all software and programming methods support the output of tool contact point coordinates, and when the tool contact point coordinates are unknown, the existing algorithm cannot calculate the compensation vector. SUMMARY

[0010] The technical problem solved by the application is to overcome the shortcomings of the prior art, and provide a post-processing method for radial compensation of round hole machining, which is not limited by the functions of numerical control systems and does not depend on tool contact point coordinates. The radial compensation vector of round hole machining can be calculated based on tool position coordinates and tool axis vectors, a numerical control machining program of a round hole with different diameter allowances can be generated, accurate compensation machining of the round hole is realized, and the method has the advantages of high efficiency, convenience and high machining precision.

[0011] The technical solution of the application is:

[0012] A post-processing method for radial compensation of round hole machining, comprising

[0013] A. obtaining three tool position points C1, C2, C3 and a tool axis vector n on a tool path trajectory of round hole machining;

[0014] B. obtaining a center reference point O on a center axis l of the round hole according to the tool position points C1, C2, C3 and the tool axis vector n;

[0015] C. obtaining a target tool position point M on the tool path trajectory of round hole machining, and obtaining a radial compensation unit vector ω at the target tool position point M according to the center reference point O, the tool axis vector n and the target tool position point M;

[0016] D. obtaining a compensated tool position point M' after radial compensation according to the target tool position point M, the radial compensation unit vector ω and a target compensation value δ.

[0017] The three tool position points C1, C2, C3 in the step A should satisfy:

[0018] The tool position points C1, C2, C3 are effective cutting tool position points except for tool advancing and retreating and tool shifting.

[0019] The three tool position points C1, C2, C3 in the step A should satisfy:

[0020] A unique plane Σ passing through C1, C2, C3 can be constructed, and the plane Σ is not parallel to the tool axis vector n.

[0021] The calculation method of the center reference point O in the step B is as follows:

[0022] (a) constructing a plane Ψ passing through the tool position point C1 and perpendicular to the tool axis vector n to obtain a standard equation of the plane Ψ;

[0023] (b) calculating the coordinates of a foot point F2 of the tool position point C2 on the plane Ψ and the coordinates of a foot point F3 of the tool position point C3 on the plane Ψ according to the standard equation of the plane Ψ, the tool position point C2 and the tool axis vector n;

[0024] (c) calculating the coordinates of a midpoint P of a line segment C1F2 and the coordinates of a midpoint Q of a line segment F2F3 according to the tool position point C1, the coordinates of the foot point F2 and the coordinates of the foot point F3;

[0025] (d) calculating an intersection point O of a straight line passing through the point P and perpendicular to C1F2 and a straight line passing through the point Q and perpendicular to F2F3 according to the tool position point C1, the foot point F2, the foot point F3, the coordinates of the point P, the coordinates of the point Q and in combination with the tool axis vector n.

[0026] The step (b) comprises:

[0027] Since the line segment C2F2 is parallel to the tool axis vector n, a parameter equation of the straight line where the line segment C2F2 is located is obtained in terms of t in combination with the tool position point C2 and the tool axis vector n;

[0028] The standard equation of the plane Ψ and the parameter equation of the straight line where the line segment C2F2 is located are combined to obtain the value of the parameter t corresponding to the foot point F2, and the value of the parameter t is substituted into the parameter equation of the straight line where the line segment C2F2 is located in terms of t to obtain the coordinates of the foot point F2. The coordinates of the foot point F3 of the tool position point C3 on the plane Ψ are calculated in the same way.

[0029] The step (d) comprises:

[0030] The vector v1 of the line segment C1F2 is calculated in terms of t according to the tool position point C1, the foot point F2 and in combination with the tool axis vector n;

[0031] The parameter equation of the straight line passing through the point P and perpendicular to C1F2 is obtained according to the vector v1 and the coordinates of P;

[0032] The vector v2 of the line segment F2F3 is calculated according to the foot point F2, the foot point F3 and in combination with the tool axis vector n;

[0033] The parameter equation of the straight line passing through the point Q and perpendicular to F2F3 is obtained according to the vector v2 and the coordinates of Q;

[0034] The parameter t corresponding to the intersection point O is obtained by combining the parameter equation of the straight line passing through the point P and perpendicular to C1F2 and the parameter equation of the straight line passing through the point Q and perpendicular to F2F3. O The parameter t is substituted into the parameter equation of the straight line passing through the point P and perpendicular to C1F2 to obtain the coordinates of the foot point F2. O The coordinates of the intersection point O are obtained by substituting the parameter t into the parameter equation of the straight line passing through the point Q and perpendicular to F2F3.

[0035] The calculation method of the radial compensation unit vector ω at the target tool position point M in the step C is as follows:

[0036] The vector v is obtained according to the coordinate vector r M of the target tool position point M, the coordinate vector r O of the center reference point O, and the tool axis vector n.

[0037] The plane passing through the target tool position point M and perpendicular to the tool axis vector n is Π, and the intersection point of the center axis l and the plane Π is O1. The tangent vector τ perpendicular to the plane MOO1 is obtained according to the coordinates of the target tool position point M and the tool axis vector n.

[0038] The direction vector of the line segment MO1 is obtained according to the vector τ and the tool axis vector n, and the line segment MO1 is perpendicular to the circular hole center axis l.

[0039] The vector​ Unitization, that is, the radial compensation unit vector ω at the tool position point M is obtained.

[0040] The calculation method of the compensation tool position point M' in the step D is as follows:

[0041] The coordinate vector of the tool position point M' is denoted as r M' , and the target compensation value is δ

[0042] r M ' = r M + δ·ω.

[0043] In summary, the present application at least includes the following beneficial technical effects:

[0044] The present application provides a post-processing method for radial compensation of circular hole machining, a convenient and efficient radial compensation machining principle is researched for circular hole machining, and an accurate calculation equation of the circular hole machining radial compensation vector based on the tool position coordinate and the tool axis vector is derived. Based on the provided method principle, a post-processing program with radius compensation function can be developed, a compensation machining numerical control program is efficiently generated, and efficient, convenient and high-precision compensation machining of the circular hole is realized. BRIEF DESCRIPTION OF DRAWINGS

[0045] Fig. 1 is a fixed axis machining schematic diagram of a hole. 1 represents a circular hole to be machined, 2 represents a machining tool, and 3 represents a circular hole machining tool path;

[0046] Fig. 2 is a fixed axis machining tool path schematic diagram of a hole. Among them, 3 represents a circular hole machining tool path, l is a circular hole center axis, n is a tool axis vector, C1, C2, C3 are any three tool position points on the tool path 3;

[0047] Fig. 3 is a calculation method schematic diagram of a center reference point O on the circular hole center axis l. Among them, 3 represents a circular hole machining tool path, l is a circular hole center axis, n is a tool axis vector, C1, C2, C3 are any three tool position points on the tool path 3, Ψ is a plane passing through point C1 and perpendicular to the tool axis vector n, F2 is the foot point of the tool position C2 on the plane Ψ, F3 is the foot point of the tool position C3 on the plane Ψ, point P is the midpoint of the line segment C1F2, point Q is the midpoint of the line segment F2F3, v1 is a vector perpendicular to the line segment C1F2, v2 is a vector perpendicular to the line segment F2F3, and point O is a center reference point on the circular hole center axis l.

[0048] Fig. 4is a schematic diagram of a calculation method of a radial compensation unit vector ω and a compensated tool position M'. Wherein 3 represents a circular hole machining tool path, l is a circular hole center axis, n is a tool axis vector, point O is a center reference point obtained by solving, point M is a target tool position on the tool path 3, Π is a plane passing through the target tool position M and perpendicular to the tool axis vector n, point O1 is the intersection of the center axis l and the plane Π, τ is a tangent vector perpendicular to the plane MOO1, ω is a radial compensation unit vector at the target tool position M, δ is a target compensation value, and M' is a compensated tool position. DETAILED DESCRIPTION

[0049] The application will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0050] The embodiments of the application disclose a post-processing method for radial compensation of circular hole machining, referring to Figs. 1 to 4 , comprising the following steps:

[0051] Step A, obtaining three tool positions C1, C2, C3 and a tool axis vector n on a circular hole 1 machining tool path 3. Wherein the tool positions C1, C2, C3 should satisfy the following two conditions at the same time:

[0052] (a) the tool positions C1, C2, C3 are effective cutting tool positions except for tool feeding and tool moving;

[0053] (b) a unique plane Σ passing through C1, C2, C3 can be constructed, and the plane Σ is not parallel to the tool axis vector n.

[0054] Step B, obtaining a center reference point O on the center axis l of the circular hole 1 according to the tool positions C1, C2, C3 and the tool axis vector n, and the calculation process is as follows:

[0055] (a) recording the coordinates of the tool positions C1, C2, C3 as [x1, y1, z1], [x2, y2, z2], [x3, y3, z3] respectively, and the coordinates of the tool axis vector n as [I, J, K];

[0056] (b) constructing the equation of the plane Ψ passing through the tool position C1: [x1, y1, z1] and perpendicular to the tool axis vector n:

[0057] I(x-x1)+J(y-y1)+K(z-z1)=0 (1)

[0058] Converting it into the standard equation of the plane is:

[0059] Ix+Jy+Kz-Ix1-Jy1-Kz1=0 (2)

[0060] (c) calculating the coordinates [x'2, y'2, z'2] of the foot point F2 of the tool position C2 on the plane Ψ, and the coordinates [x'3, y'3, z'3] of the foot point F3 of the tool position C3 on the plane Ψ:

[0061] Since the line segment C2F2 is parallel to the tool axis vector n, the parametric equation of the straight line on which the line segment C2F2 lies is:

[0062]

[0063] Solving equation (2) and equation (3) together to calculate the value of the parameter t corresponding to the foot point F2:

[0064] t = [I(x1-x2) + J(y1-y2) + K(z1-z2)] / (I 2 + J 2 + K 2 ) (4)

[0065] Substituting equation (4) into equation (3) to obtain the coordinates of the foot point F2:

[0066]

[0067] Similarly, the coordinates [x'3, y'3, z'3] of the foot point F3 of the tool position C3 on the plane Ψ are calculated as:

[0068]

[0069] (d) calculating the coordinates [x p ,y p ,z p ] of the midpoint P of the line segment C1F2, and the coordinates [x q ,y q ,z q ] of the midpoint Q of the line segment F2F3:

[0070]

[0071]

[0072] (e) calculating the intersection point O of the straight line passing through point P and perpendicular to C1F2 and the straight line passing through point Q and perpendicular to F2F3:

[0073] The vector v1 perpendicular to the line segment C1F2 is [i1, j1, k1]:

[0074]

[0075] The parametric equation of the straight line passing through point P and perpendicular to C1F2 is:

[0076]

[0077] The vector v2 perpendicular to the line segment F2F3 is [i2, j2, k2]:

[0078]

[0079] The parametric equation of the straight line passing through point Q and perpendicular to F2F3 is:

[0080]

[0081] Solving equation (10) and equation (12) simultaneously, the value of the parameter t corresponding to the intersection point O is: O

[0082]

[0083] Solving equation (12) and equation (13) simultaneously, the coordinate value of the intersection point O is:

[0084]

[0085] Point O is the center reference point on the center axis l of the circular hole 1.

[0086] Step C, obtaining a target tool position point M on the tool path trajectory 3 of the circular hole 1, and obtaining a radial compensation unit vector ω at the target tool position point M according to the center reference point O, the tool axis vector n, and the target tool position point M, the calculation process is as follows:

[0087] (a) Let the coordinate vector of the target tool position point M be r M , and the coordinate vector of the center reference point O be r O , the coordinates of the vector are:

[0088]

[0089] (b) The plane passing through the target tool position point M and perpendicular to the tool axis vector n is Π, the intersection point of the center axis l and the plane Π is O1, and the tangent vector τ perpendicular to the plane MOO1 is:

[0090]

[0091] (c) The line segment MO1 is perpendicular to the center axis l of the circular hole 1, and the direction vector is:

[0092]

[0093] (d) Unitize the vector , that is, the radial compensation unit vector ω at the tool position point M is obtained:

[0094] ​​

[0095] Step D, according to the target tool position point M, the radial compensation unit vector ω and the target compensation value δ, a compensated tool position point M' is obtained, and the calculation process is as follows:

[0096] Let the coordinate vector of the tool position point M' be r M′ , and the target compensation value be δ

[0097] r M′ = r M + δ·ω (19)

[0098] According to the above method, the radial compensation vector for circular hole machining can be accurately calculated based on the tool position coordinates and the tool axis vector. Based on the above method, a post-processing program with radius compensation function can be developed, a compensated machining numerical control program can be efficiently generated, and high-efficiency, convenient and high-precision compensation machining of the circular hole can be realized.

[0099] Although the present application is disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be subject to the scope defined by the claims of the present application.

Claims

1. A post-processing method for radial compensation of round hole machining, characterized in that: including Step A, obtaining three tool position points on the circular hole machining tool path C 1、 C 2、 C 3 and tool axis vector n ; Three tool positions C 1, C 2, C 3 simultaneously satisfy: tool positions C 1, C 2, C 3 are effective cutting tool positions other than tool approach and tool retreat. Three blade sites C 1. The method of claim 1, wherein the three blade sites are simultaneously satisfied. C 2. The method of claim 1, wherein the three blade sites are simultaneously satisfied. C 3. The method of The plane C 1、 C 2、 C 3 can be constructed such that the plane ∑ , and the plane ∑ is not parallel to the tool axis vector n . Step B, the cutter location point according to the cutter location point C 1、 C 2、 C 3 and the tool axis vector n obtaining a center reference point located on the center axis of the circular hole l O ;​ Step C: Obtain the target tool position point on the toolpath trajectory for machining the circular hole. M and based on the central reference point O Tool axis vector n and the target tool position M Obtain the target tool position M Radial compensation unit vector at the location ω ; The target knife location point in the step C M The radial compensation unit vector at the point ω The calculation method is as follows: Based on the target tool position M coordinate vector r M Central reference point O coordinate vector r O To obtain the vector coordinate; Through the target tool position M And perpendicular to the tool axis vector n The plane is ∏ central axis l With plane ∏ The intersection point is O 1. According to Coordinates, tool axis vector n To obtain a plane perpendicular to the plane MOO Tangential vector of 1 τ; line segment MO 1 perpendicular to the central axis of the circular hole l , according to the vector τ, tool shaft vector n , the direction vector of the line segment MO 1 is ; vector unitize, i.e. get the radial compensation unit vector M at the tool position ω ; Step D, obtaining a compensated tool position point according to the target tool position point M , a radial compensation unit vector ω , and a target compensation value δ obtaining a compensated tool position point after radial compensation M´ ; The compensation isocenter in step D The calculation method is as follows: Tool position The coordinate vector of the tool position point is The target compensation value is δ , 。 2. The post-processing method for radial compensation of round hole machining according to claim 1, characterized in that: The center reference point in step B O The calculation method is as follows: Step (a) constructs a plane through the tool position C 1 and perpendicular to the tool axis vector n of the plane Ψ, of the plane Ψ gives the standard equation of the plane; Step (b) is based on the plane Ψ Standard equations, tool position points C 2. Tool axis vector n Calculate the tool position point C 2 in plane Ψ foot of the perpendicular F 2. Coordinates and tool position C 3 in plane The step (b) comprises, foot of the perpendicular F The coordinates of 3; Step (c) according to tool position C 1, foot point F 2, foot point F 3, coordinates of midpoint of line segment C 1 F 2 P 3, coordinates of midpoint of line segment F 2 F 3, coordinates of midpoint of line segment Q 2 Step (d) is calculated from the tool position C 1 F 2 F 3 P coordinates of Q coordinates of n and the tool axis vector P The intersection of the line perpendicular to C 1 F 2 Q and the line perpendicular to F 2 F 3 O is calculated.

3. The post-processing method for radial compensation of round hole machining according to claim 2, characterized in that: n, get Since the line segment C2F2 is parallel to the tool axis vector n , with t as parameter, the tool position C 2, the tool axis vector Ψ to the straight line on which the line segment C2F2 lies has the parametric equation with t as parameter; Joint plane Ψ From the standard equation and the parametric equation of the line containing C2F2, we can obtain the foot of the perpendicular. F Parameters corresponding to 2 t The value of the parameter t Substitute the value of line segment C2F2 into the line about t From the parametric equations, we obtain the foot of the perpendicular. F Similarly, calculate the tool position point based on the coordinates of 2. C 3 in plane The step (d) comprises, foot of the perpendicular F The coordinates of 3.

4. The post-processing method for radial compensation of round hole machining according to claim 2, characterized in that: ​ According to tool position point C 1, foot point F 2, and combining tool axis vector n , calculate vector C 1 F 2 of line segment ; According to the vector , P of the coordinates and with t as parameter, the parametric equation of the straight line through the point P perpendicular to C 1 F 2 is obtained; According to the foot point F 2, the foot point F 3, in combination with the tool axis vector n , the vector F 2 F 3 of the line segment ; According to the vector , Q of the coordinates, and taking t as a parameter, the parametric equation of the straight line passing through the point Q and perpendicular to F 2 F 3 is obtained; Jointly pass point P Perpendicular to C 1 F Parametric equation of the line 2, passing through the point Q Perpendicular to F 2 F Find the parametric equation of the line 3 and obtain the intersection point. O Corresponding parameters t O ， parameters t O Substitute the point Q Perpendicular to F 2 F The intersection point can be found from the parametric equation of line 3. O The coordinates.

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