JPS60118451A - Numerically controlled machining with use of tapered tool - Google Patents

Abstract

PURPOSE:To enable a curved face defined by two curved lines to be machined and the lower portion thereof to have a step, by representing shapes into which the upper and lower faces of a work to be machined by first and second curved lines, respectively, and performing machining operation with a tapered tool point projected or retracted by a predetermined amount from the lower face. CONSTITUTION:A curved line CV1 represents a shape into which the upper face of a work W is to be worked, while a curved line CV2 represents a shape into which the bottom face of the work is to be machined. A tool end correction value (d') which is a predetermined value indicates an amount by which the end of a taper tool is projected or retracted from a point (ni) on the curved line CV2 on the bottom face in the direction of generatrix spectrum of the curved face. Accordingly, if (d') is zero, the tool end is not projected or retracted from the bottom face. The correction value (d') is set positive so that the taper tool is projected from the work face to machine it, whereby an excellent finish shape can be obtained without producing any ruggedness on the bottom face of the work when machining a curved face defined by connecting the corresponding points of the two curved lines. Further, it is enabled to machine a part having a step in the lower portion of said curved face by setting the correction value (d') negative.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a numerically controlled machining method for machining a curved surface formed by connecting corresponding points of two curved lines with a body C cutter side of a tapered tool.

<Conventional technology> As shown in Figure 1, two curves CV1%CV.

There is a method of numerically controlling the curved surface SF formed by connecting the above corresponding points (-1=1.2, . . . ) using the body of the tool BT. This processing method uses the first and second curves Cv1, c
Corresponding point m is n i (1=1.2,...
) is controlled to move the tool BT relative to the workpiece WK so that the body (cutter side) of the tool BT follows at the same time to perform curved surface machining. It is effective. Further, according to this machining method, machining efficiency can be significantly improved compared to a method of machining only the tip of the tool BT as shown in FIG.

<Disadvantages of the Prior Art> By the way, the tool used in the conventional method has a tool diameter that is constant in the tool axis direction, as shown in FIGS. 3(A) and 3(B). For this reason.

In the conventional method described above, it was not possible to process a curved surface formed by connecting corresponding points of two curved lines using a tool with a chi and flat as shown in FIGS. 4(A) and 4(B).

In addition, in the conventional machining method, as shown in FIG. 5, first and second
Corresponding points mi, n1 (i = 1.2.3,...
・) Find the tool compensation positions ml' and ni' offset in the normal direction of the curved surface by the tool radius r, respectively, and set the tool center axis T.
Machining is performed by moving the tool BT relative to the workpiece WK so that CL is located at the tool compensation position mi'%ni' at the same time (7), and the center position of the tool tip is at the tool compensation position. n l/(i-1, 2, . . . ) continuously, and the tool tip end moves along the second curve on the lower surface of the workpiece.

As described above, in the conventional method, the tip of the tool moves along the second curve on the lower surface of the workpiece, which causes fluff on the lower surface of the workpiece, making it difficult to perform good machining.Moreover, it has the disadvantage of poor machinability. Ta.

Also, depending on the part, a part with a step at the bottom of the workpiece may be required, but in the conventional method described above, the tool tip moves along the second curve on the bottom surface of the workpiece, so it is not possible to process a part with a step at the bottom of the workpiece. There was a drawback that it could not be done.

<Objective of the Invention> An object of the present invention is to provide a numerically controlled machining method (8) that allows machining of a curved surface formed by connecting corresponding points of two curved lines using a tapered tool.

Another object of the present invention is to use numerical control to machine a curved surface formed by connecting corresponding points of two curves by protruding a tool tip with a cheat T4 a predetermined amount from the lower surface of the workpiece and using the body (cutter side) of the tool. The purpose is to provide a processing method.

Still another object of the present invention is to machine a curved surface formed by connecting corresponding points of two curves with the tip end of a tapered tool raised from the lower surface of a workpiece to a part having a step at the lower part of the workpiece. The object of the present invention is to provide a numerically controlled machining method that obtains.

<Summary of the invention> FIGS. 6 and 7 are schematic illustrations of the present invention. The present invention provides a corresponding point m1 on the first curve cvl and the second curve CV.
%nl ('i = 1.2, .) is a numerically controlled machining method in which the curved surface SF formed by connecting the two curves cvl, CV,
curve information that specifies, data that specifies the chi/4' angle α of the tapered tool, the tool radius r of the tool tip, the tool tip position correction amount d or d', and data that includes at least the tool radius correction direction. Step of inputting: Inputting a normal vector N in the tool correction direction perpendicular to the generatrix vector S connecting the corresponding points mi and ni on the two curves, as well as inputting the generatrix pect tool center axis vector T and the tool center axis. The step of finding a vector R perpendicular to each vector, finding a position vector Pl of a point shifted from the corresponding point ni in the direction of the generatrix vector by an amount corresponding to the tool tip position correction amount, and Step of calculating the position vector Pl of the center of the tool tip from the vector R and the tool radius r of the tool tip. Calculating the movement data of each axis of the numerically controlled machine tool using the position vector Pl of the center of the tool tip and the tool center axis vector T. This is a numerically controlled machining method using a tapered tool, which includes a step of performing curved surface machining by moving the tapered tool BT relative to the workpiece WKK based on the movement data of each axis. By setting the tool tip position correction amount d' to zero, the tool can be brought to the position shown by the dotted line in FIG. 7 and the curved surface SF can be machined.

<Example> Hereinafter, the numerical control processing method of the present invention will be explained in detail with reference to FIGS. 6 and 7.

(1) First, before processing the curved surface, two curves CVt
, CV@ and the curve information that specifies the tip pJ of the tapered tool? Tool shape information such as data specifying angle α and tool radius r at the tool tip, and tool radius correction direction information (G function command G41 or 04m. G41 is off-sera on the left)
%G4m is a right-side offset), division information for dividing each of the curves, tool tip position correction amount d or d', and tool length t are input and stored in the memo IJIC. Listen, song +1
1ilCvl is the machining shape of the upper surface of the workpiece WK, the curve Cv
3 is the (11) machining shape of the lower surface of the workpiece, and the tool tip position correction amount d' is the amount by which the tool tip is protruded or pulled up in the direction of the generatrix vector of the curved surface from the point ni on the curve Cv of the lower surface, and d
When '=0, the tool neither protrudes nor is pulled up from the underside of the workpiece.

(2) Next, each of the curves CVt and CVs is divided based on the division information input in step (1), and a dividing point m1bni is determined. For example, if the number of divisions M is input as division information, the division points for dividing each curve into A:B can be determined by the following steps 2-1) to 2-4) (#%A+B=M) .

2-1) First curve CV or second curve CV.

Find the length of each line element (the line segment or arc that makes up the curve is called a line element), and add them up to find the length D of the curve.

2-3) Extract a line element that includes a position of length D' from one end of the curve that is the base point of division.

Cl2) To extract this line element, the length of the first line element is D1%, the length of the next line element is Do, and so on. This is done by

2-4) For the kth line element, find a point on the kth line element from the starting point. This point is the point that divides the curve from one end point into A:B. Oka, 2-3), l(= 1) and the division pitch N(w*) as division information.
is given,\ is the dividing point m i sni by the following procedure
I put it on.

2-1)' 1st curve CVs and 2nd curve CVs.

Find the lengths DB (m) and DI (11111).

2 +, 2)' Mt = Dt /N%M snow =
Calculate D t /N.

2-3)' Comparing the magnitudes of M1 and M, using the larger one as the number of divisions, and executing steps 2-2) to 2-4), the division point m is n l is determined.

(3) Corresponding dividing point ml on curves cv, , cvz
If s n i is 1, the normal vector N in the tool radius correction direction at the second curve CV specifying the shape of the lower surface of the workpiece and the upper dividing point n1 is calculated.

This normal vector N can be determined by the following procedure with reference to FIGS. 8 and 9.

3-1) Division point n one before and one after division point ni
Add 1-1 s ni+1. However, since the previous division point n1-1 has already been calculated when the tool BT moves by ml-1 and nl-IK, it is only necessary to find the division point n1-1.

3-2) Find the arc CRI (Fig. 8) passing through the above three points nl -1, nl, nl+1, and find the tangent vector U (unit vector) tangent to the arc CR at the 1 division point ni.

3-3) Next, by twisting the generatrix vector S (unit vector) of the curved surface SF, the normal vector N at the division point ni is calculated from the tangent vector (Figure 9), N=8XU. However, the symbol norm indicates a unit vector, and P
m1 and Pnl are position vectors of the dividing point m1%ni.

(4) Next, the generatrix vector S, the normal vector N, and theno'? From the angle α, a tool center axis vector T and a vector R perpendicular to the tool center axis vector are calculated using the following equation (15). Now, the tool center axis vector T and vector R are (
5), Please refer to FIG. 10 for the reason based on equation (e).

The position vector Pi of the point P1 shifted by the tool tip position correction amount d' in the line vector direction is determined by the following equation: Pl-Pnl-d'.5(7). d shown in Fig. 7 as the tool tip position correction amount.
is given, d'=d/possible α according to the following formula (8) After determining d', perform the calculation of formula (7).

(6) Next, from the position vector P1, the vector R, and the tool radius r at the tool tip, the position vector P at the center of the tool tip is calculated.
i is calculated from the following formula: PH=P1+r-R(9).

(16) (7) After scanning, the position vector Pi (
X, Y, Z) and tool center axis vector T (I, J, K)
The position data of each control axis of the numerically controlled machine tool is calculated from. For example, as shown in FIG. 11, the tool BT is rotated in the vertical rotation direction (B-axis direction) and the horizontal rotation direction (CC-axis direction) to control the tool center axis direction with respect to the workpiece, and the tool is rotated by X%Y, Considering a simultaneous 5-axis milling machine that performs desired machining on a workpiece by moving in the 3-axis directions of z, the tool center axis vector T (1, J, K) and the position vector P1 (X%Y %z) and the tool length t, the orthogonal coordinate value of the tool rotation center Q (X% 3'% Z),
The spherical coordinate values (b, c) indicating the rotational angular position of the tool BT can be calculated from the following equation.

■ -1v/π=d Q3 b=tan() , α field, Equation 64 is a conversion equation from the orthogonal coordinate system to the spherical coordinate system. That is, as shown in Fig. 12, assuming an orthogonal coordinate system and a spherical coordinate system with the rotation center Q of the tool BT as the origin, a tool of length t is moved in the B-axis direction (vertical rotation direction by b% in the axial direction (horizontal When the tool is rotated C in the direction of rotation), the orthogonal coordinates of the tool tip (I
%J%K) is I=t-self b1 part c QQ J=l -5fnb -1(11c QIK=1(2)
Expressing it as b Qη and subtracting b% C from these formulas 00 to 69, we get (
(to), which becomes formula 64.

(8) Finally, OI ~ α → X, y from the formula.

Simultaneous 5-axis pulse distribution calculation is performed using 2% b and e to move the tool BT from division point m i + 1 of curve cvl to division point ml and from division point n1-s of curve CV to division point nl. move it.

Thereafter, by repeating steps (1) to (8) above and moving the tool BT along the curves CVl and CV, milling of the desired curved surface SF is performed.

In the above, if d'=0, the tip end of the tapered tool moves along the second curve that specifies the machining shape of the lower surface of the workpiece, and if d'>0, the tip end of the tapered tool moves along the second curve that specifies the machining shape of the lower surface of the workpiece. The part protrudes from the lower surface of the workpiece by d' in the direction of the generatrix vector, allowing for good machining.
The tip end of the +-marked tool is pulled up by d' from the lower surface of the workpiece in the direction of the generatrix vector to perform bottomed curved surface machining. In addition, although the above description assumes that d' is input, if the tip end of the tapered tool is to be processed by moving along the second curve K (19), d' is not input and the step ( The system can be configured to omit step 5).

Furthermore, in the above, the case where the number of divisions or the division pitch is input, the division points mI, nB of the first and second curves are found, and the division points mi%"i of these first and second curves are taken as corresponding points. Although described above, corresponding points may be found by inputting curve information as follows.In other words, the first curve CV
1 and the second curve Cvs as the 13th line element, respectively.
KGl, Gs as shown in the figure.

Gs%Gy ・”: Gss G4 s Gs, Gs
``', and the line element G, and GM, GM and G, , G, and G
, , G, and C8...... are assumed to correspond to each other, then the curve information is as follows: Gl: Sl s S wealth, 40 G meaning: 811% S7% 40 Gg: C1, CWs s, , ss, 40G4
: Cg % CWs 81 s 8@s 40...
・(4) Gs:Ss%s,,a.

C20] Gg: 86% Sg, 30 G7: C3, CWs 541i ss, 50G@
: 811, 810% 50. However, the end point S1-5to 1 arc C1 of each line element
, CI, and C3 have already been defined. Also, cw'' in the above curve information indicates a clockwise circular arc, and the numerical value 30.40.50 at the end is the number of divisions of each line element G1. The number of divisions is M, and the coordinate values of the two points Pa%pb are (x,, yl
l), (x B, yb), the straight line LM connecting the two points
The coordinate values xj, yj (j=1.2, ・
...M) becomes. or,! As shown in Figure 14 (B), C0 is the central angle, r is the arc radius, M is the number of divisions, and θ(
θ. /M) is the angular increment, then the coordinate value xj%yj of the j-th division point Pj, (j=1.2,...M) is X j''X j-1'cos θ-y・1・Gang θ (19
&)-7j"xj-1" stone θ+7j-□'Cmθ (19b
). However, in the above formula, X (1"" X a , Y
``'3' B.

FIG. 15 is a block diagram showing an embodiment of the present invention. In the figure, 101 is curve information D specifying the first curve and the second curve.
CV 1 s D CV 2 , Taper angle α of tapered tool, Tool diameter r of tool tip, Tool length t1 Tool correction direction data G41 or 041 % Cutting speed F, Division information for dividing each curve M1 Tool tip position correction amount d' is recorded on an external storage medium, and 102 is an input control unit which reads the above information from the external storage medium 101 and creates a curve 7''-IDCVI.
, DCV, are stored in the first memory 03, and the number of divisions M,
Theno+angle α, tool radius r, tool length t, tool tip position correction td'Th, cutting speed F, and tool correction direction data are stored in the second memory 104. 105 is an operation panel, 106 is a numerical control unit, 10T is a dividing point calculation unit, and the curve Cv
1, the curve data DCV1, DCV specifying Cvl, and the division ratio A2B are input, and the division point m1. Calculate the coordinate value of nl.

108 is a division ratio storage register, and the above-mentioned (11 to (
Every time step 8) is completed, the numerical control unit 106 performs the calculation 1+1→A % M−A−)B i1 , and the result of the calculation is stored.

Oka, initially 1=0. 109 is a dividing point coordinate storage register, which stores the current dividing point mi where the tool is currently located at position 1.
-1, J-1, the division points mi, ni to which the tool moves next, and the next next division point m1nt.

"i+x" position vectors are respectively stored.

110 is an arithmetic unit that calculates the generatrix vector and the normal vector, and uses the tool radius correction direction information given by the G function command to calculate the generatrix vector S' and A normal vector N at the dividing point nIK of the second curve is calculated. 1
11 is an arithmetic unit that calculates a tool center axis vector T and a vector R perpendicular to the tool center axis vector using equations (5) and (6); 112 is a calculation unit for calculating a point Pi shifted by d' in the direction of the generatrix vector from the division point n1; 113 is a calculation unit that calculates the position vector → I Pl from equation (7); 113 is a calculation unit that calculates the position vector at the center of the tool tip; and (9) 2 calculates the position vector Pl at the center of the tool tip.
(X-YsZ) is calculated. 114 is a position data calculation unit, which calculates the tool center axis vector T (I, J, K
) and the position vector PI of the center of the tool tip (X%Y, Z
) and tool length t are input, and from formula 01-04, X%Y12
The position data x, y, z, and 5% C of the axis and 8% C axis are calculated and output. 115 is an i4 pulse distributor, and device data ΔX1ΔY1Δ constituted by the numerical control section 106
2. ΔB1ΔC is input, and the well-known 9-pulse distribution calculation is executed (24) to generate distribution pulses X2, Yl, 21, B9, and C for each axis. Similarly, each axis distribution node 9 is each axis's sensor (not shown). It is input to the circuit and drives the motor of each axis to move the tool to the curve CVt%CV.

move it along.

The numerical control section 106 is connected to the position data calculation unit 114.
The position data X s )' 5zsbsc of each axis is input from , and the calculation is performed to determine the division ratios A and B, which are stored in the division point storage register 08 and sent to the division point calculation unit 107 . Instructs to start the next division point calculation. Further, the numerical control unit 106 calculates the difference between the current position of each axis XYY2BC& stored in the current position memory 16 and the manually input position DE1Xs ys Z%b,c. Axis incremental value Xi%Yi%z1, B1-
Cl, and from these and the cutting speed F, calculate the velocity components Fx%Fy%F2, Fb%F0 in each axis direction using the following formulas, and then calculate the predetermined time ΔT (for example, 16m1・C). The amount of movement Δ that should be moved in each axis direction during
X1ΔY, Δ2. ΔB.

ΔC is the following formula %formula% Therefore, these ΔX1ΔY1Δ2. ΔB.

Pulses of ΔC are output to the distributor 115 every time ΔT.

The pulse distributor 115 simultaneously outputs 5 axes of data based on the input data. The distribution pulses X1, Yl, 2 are calculated by performing pulse distribution calculation.
1, B2, and C9 are generated and output to a sarpo circuit (not shown) for each axis, and the tool is moved along the cutting path.

The numerical control unit 106 also updates the current position memory 116 every 31 seconds.
Current position Xa, Y, L%Z,, Ba.

C0 by the following formula Xa±ΔX-+X8 Ya±ΔY−+Y.

Z&Sat Δ2−→za Ba±ΔB-)B.

Ca±ΔC-+C,L (updated, the sign depends on the movement direction), and the remaining movement amount X which is similarly stored in the remaining movement amount memory 117 every 31 seconds.
r%Yr1zr%Br, cr (initial values are Xi, respectively
Yi, Zi, Bl, cl) are updated as follows: The numerical control unit 106 then calculates Xr-Yr=zr=Br=Cr=.

Then, the next position data is calculated by the position data calculation unit 11.
- Import from 4 and repeat the above process.

Further, when reading data from the external storage medium 101, when a reading command is received from the operation panel 105, the numerical control unit 106 instructs the input control unit 102 to start reading. Furthermore, a start command for numerically controlled machining is also issued from the operation panel 105, and upon receiving the start command, the numerical control unit 106 calculates the division ratio A, B by calculating the equation (E) as Q − + i. is stored in the division ratio register 10B, and at the same time instructs the division point calculation unit 1oT to perform division point calculation.

(28) <Effects of the Invention> As explained above, according to the present invention, a curved surface formed by connecting corresponding points of two curves can be machined using a tool with a Teno N.

Furthermore, according to the present invention, it is possible to machine a curved surface formed by connecting the corresponding points of two curves on the cutter side by protruding the tip of the tapered tool by a predetermined amount from the lower surface of the workpiece, so that no fluff will occur on the lower surface of the workpiece. It is possible to process curved surfaces with a good finished shape and good machinability.

Furthermore, according to the present invention, by appropriately determining the tool tip correction amount, a curved surface formed by connecting corresponding points of two curves can be machined while the tip end of the tapered tool is lifted up a predetermined amount from the lower surface of the workpiece. It is possible to obtain a part with a step at the bottom of the workpiece.

However, the block diagram shown in FIG. 15 can also be constructed using a microcomputer, in which case the processing of the processor will be based on the above-mentioned steps (11 to (8)K). In this case, the machine tool is controlled by immediately performing the Kt4 pulse distribution calculation based on the position data, but an NC tape is once created using the position data, and the NC tape information is input into the NC device. Numerical control processing is also possible.

[Brief explanation of drawings]

Fig. 1, Fig. 2, and Fig. 5 are explanatory diagrams of a conventional numerical control machining method, Fig. 3 is an explanatory diagram of a tool with a constant diameter used in the conventional method, and Fig. 4 is an explanatory diagram of a tool with a constant tool diameter used in the present invention. Explanatory diagram of the tool, Figure 6 and! FIG. 7 is an explanatory diagram of the numerically controlled machining method according to the present invention, FIGS. 8 and 9 are illustrations of calculation of normal vectors, FIG. 10 is an illustration of calculation of tool center axis vector, etc., and FIGS. FIG. 12 is an explanatory diagram of position data calculation method for each axis, FIG. 13 is an explanatory diagram of curve information, and FIG. 14 is an explanatory diagram of corresponding point calculation.% FIG. 15 is a block diagram showing an embodiment of the present invention. 101... External storage medium 102... Input control unit 103... First memory 104... Second memory 106... Numerical control unit 107... Division point calculation unit 109...
...Division point coordinate storage registers 110 to 113...
- Arithmetic unit 114...Position data computing unit 115...l? Patent applicant for Luz distributor Fanuc Co., Ltd. Patent attorney Chiki Saito (31)

Claims (8)

[Claims] (1) In a numerically controlled machining method that uses a curved tapered tool formed by connecting corresponding points on a first curve and a second curve, curve information that specifies the two curves and the taper of the tool are used. A step of inputting data specifying the angle α and the tool diameter at the tool tip, and data including at least the tool radius correction direction, and inputting data specifying the tool radius correction direction perpendicular to the generatrix vector S connecting the corresponding points ml and nl on the two curves. The tool center axis vector T is determined from the normal vector line vector N and the tenor angle α.
and a step of calculating a vector R perpendicular to the tool center axis vector, and calculating the corresponding point nl from the position vector Pni of the corresponding point ni, the vector R, and the tool radius r of the tool tip.
a step of calculating a tool compensation position nl' offset by the tool radius, a step of calculating each axis movement data of the numerically controlled machine tool using the tool correction position vector P' and the tool center axis vector i; A numerically controlled machining method using a tapered tool that has a step of performing curved surface machining by moving the tool relative to the workpiece based on . (2) The tool center axis vector T and the vector R perpendicular to the tool center axis vector are calculated by (1)
) Numerical control machining method using a tapered tool described in section 2. (3) The tool correction position vector Pnl' is calculated by (1) or (3)
2) Numerical control machining method using a tool with a techno 4 as described in section 2). (4) In a numerically controlled machining method in which a curved surface formed by connecting corresponding points on a first curve and a second curve is machined using a tapered tool, curve information specifying the two curves and the taper of the tool are used. A generatrix vector connecting the corresponding points mi%ni on the curves of Stella 1 and 2 into which data specifying the angle α and the tool diameter at the tool tip, the tool tip position correction amount, and the data including at least the tool radius correction direction are input. If we include the normal vector N in the tool correction direction perpendicular to S, we get ``i'? angle α
A step of calculating a tool center axis vector T and a vector R perpendicular to the tool center axis vector from position vector P
(At the same time, from the position vector P1, the vector R, and the tool light (3), the position vector PI of the center of the tool tip from the tool radius r at the end)
The step of calculating the position vector Pi of the center of the tool tip
and a step of calculating each axis movement data of a numerically controlled machine tool using the tool center axis vector T, and a step of performing curved surface machining by moving the tool relative to the workpiece based on the each axis movement data. Numerical control machining method using tools with +. (5) A tool center axis vector T and a vector R perpendicular to the tool center axis vector are calculated by
) Numerical control machining method using a tapered tool described in section 2. (6) The tool tip position correction amount in the direction of the generatrix vector is d
', then the position vector P.(4) Pi -Pni -d'.S is determined, and the position vector Pl at the center of the tool tip is determined by Pl=P1 + r.R. A numerically controlled machining method using the tapered tool according to item (4) or item (5). (7) The first curve and the second curve are used as the machining shapes of the upper and lower surfaces of the workpiece, respectively, and the tool tip position correction amount is set to a positive value to protrude the tool from the workpiece surface and perform machining. A numerically controlled machining method using a tapered tool according to claim (6). (8) Machining a part having a step at the bottom of the work by setting the first curve and the second curve as the machining shape of the bottom surface of the work, respectively, and setting the tool tip position correction amount to a negative value. Claim No. 1 characterized in (
A numerically controlled machining method using a tool with a chi as described in item 6).