JP2004276130A - Numerical value control device of five-spindle finishing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform accurate tool length correction to decrease missing of chipping regardless of the size of a pitch angle of blades of a propeller. <P>SOLUTION: A correction vector having the size corresponding to the correction amount for offsetting the length of a tool is taken in the vertical direction to a pitch angle line of blades in the workpiece, the correction vector is decomposed into the direction of Z-axis and the direction of X-axis not taken as a control axis, the correction amount in the direction of the X-axis is calculated in pseudo from the correction amount of C-axis and the correction amount of Y-axis, and on the basis of the correction amount in the direction of Z-axis, the Z-axis movement is corrected, and simultaneously the correction is made on the correction amount of C-axis and the correction amount of Y-axis. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a numerical controller having a tool length correction function required when processing a propeller blade by a five-axis control machine tool.
[0002]
[Prior art]
A propeller used for a ship is machined by a 5-axis control NC machine. Since the blade of a propeller has a complicated three-dimensional curved surface, in order to perform high-precision processing in accordance with design data, it is necessary to perform processing in consideration of the specificity of the propeller blade shape.
[0003]
Generally, a numerical control device has a tool length correction function for correcting a tool length. This tool length correction function is a function for correcting the moving amount of the tool by the length of the tool in the machining program.
[0004]
Even a numerical control device of a five-axis machine used for machining a propeller has a tool length compensation function for compensating in the Z-axis direction.
[0005]
Therefore, the concept of tool length correction in propeller machining is shown in FIG. In FIG. 7, reference numeral 2 indicates the cross-sectional shape of the blade of the propeller. The pitch angle of the blade is indicated by θ. In the coordinate system of this propeller processing machine, the vertical direction is the Z axis, the horizontal direction is the X axis, and the direction perpendicular to the paper is the Y axis. In the conventional tool length correction, a correction vector V of an amount corresponding to the tool length offset is set in parallel with the Z axis, and the correction amount is set to ΔZ, and the correction amount ΔZ is added to the Z axis movement amount to perform correction.
[0006]
[Problems to be solved by the invention]
However, in conventional propeller processing machines, when a fixed pitch propeller is machined with the tool length corrected in the Z-axis direction, an error occurs between the actual amount of blade shaving and the amount specified in the program. However, there is a problem that uncut portions are left depending on the position of the blade.
[0007]
Here, FIG. 8 is a diagram for explaining the cause of such uncut portions. In FIG. 8, among the lines indicating the cross-sectional shape of the blade of the propeller, the solid line indicates the finished surface of the blade after machining scheduled by the program, and the broken line indicates the casting surface of the blade before cutting.
[0008]
Since the surface of the propeller blade is curved, the inclination differs depending on the position. In this example of the propeller blade, when the point a near the upper end and the point b near the lower end are compared, the inclination becomes larger toward the bottom. For this reason, when processing is actually performed in a state where correction is performed in the Z-axis direction, as shown in an emphasized manner by a two-dot chain line in FIG. There is an inconvenience that it does not fall within the allowable range.
[0009]
It is known that such uncut portions do not become apparent when processing a fixed pitch propeller having a small pitch angle, but become significant when the pitch angle θ of the blade is a steep angle (45 degrees or more).
[0010]
Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to perform accurate tool length correction so as to reduce the uncut portion regardless of the pitch angle of the propeller blade. An object of the present invention is to provide a numerical control device for a 5-axis machine.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a numerical control device for a five-axis machine according to the present invention has a linear axis (Y axis, Z axis), a main axis of rotation (A axis, B axis), and a pitch angle. In a numerical control device of a five-axis machine including a rotation axis (C axis) on a rotation center of a workpiece having a blade, a correction vector having a magnitude corresponding to a correction amount for offsetting a tool length. Is taken in a direction perpendicular to the pitch angle line of the blade of the workpiece, the correction vector is decomposed into a Z-axis direction and an X-axis direction of an X-axis having no control axis, and the correction amount in the X-axis direction is obtained. Correction amount calculating means for calculating the correction amount of the C-axis and the correction amount of the Y-axis in a simulated manner, and correcting the Z-axis movement based on the correction amount in the Z-axis direction; Correction means for simultaneously adding the correction amount of the Y-axis correction amount; The is characterized in that it comprises.
[0012]
Further, the numerical control device of the five-axis propeller processing machine according to the present invention includes a linear axis (Y axis, Z axis), a turning axis of the main axis (A axis, B axis), and a rotation center of a fixed pitch propeller as a workpiece. A numerical control device having a tool correction function of applying a correction amount for offsetting a tool length in a Z-axis direction in a five-axis processing machine including a rotary axis (C-axis) of the fixed pitch propeller The reference vector of the pitch angle is made coplanar with the XY plane, and a correction vector having a magnitude corresponding to the correction amount for offsetting the tool length is taken in a direction perpendicular to the pitch angle line of the blade, and the correction is performed. The vector is decomposed into the Z-axis direction and the X-axis direction of the X-axis having no control axis, and the correction amount in the X-axis direction is simulated from the C-axis correction amount and the Y-axis correction amount. Function and said Axially at the same time it makes a correction, characterized in that it has a correction function for C-axis, a correction to the Y-axis at the same time.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a numerical control device for a five-axis machine according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a front view showing the outer shape of a five-axis propeller processing machine to which the present invention is applied. In FIG. 1, reference numeral 2 denotes a bed, and 4 denotes a column.
[0014]
On the column 2, a cross rail 6 is installed horizontally. A saddle 8 is mounted on the cross rail 6 so as to be movable left and right in the horizontal direction. The spindle head 10 is attached to the saddle 8 in a vertical posture. A table 12 is arranged on the bed 2. In FIG. 1, the Y axis is a control axis for sending the saddle 8 in the left-right direction, and the Z axis is a control axis for sending the spindle head 12 in the vertical direction. Note that the X axis is not provided in this propeller processing machine.
[0015]
In this five-axis propeller machine, in addition to the Y-axis and the Z-axis, a B-axis for rotating the spindle head 10 around the Y-axis and an A-axis for rotating the spindle head 10 around the temporary X-axis are provided. The axis that controls the rotation of the table 12 is the C axis. Therefore, this five-axis propeller processing machine is a machine tool of five-axis control of Y-axis, Z-axis and A-axis, B-axis, and C-axis.
[0016]
In FIG. 1, reference numeral 100 denotes a fixed pitch propeller which is a workpiece (hereinafter, referred to as a propeller). The center of the propeller 100 is fixed at a position coaxial with the turning axis of the table 12.
[0017]
FIG. 2 shows a block diagram of a numerical control device of the 5-axis propeller processing machine. In FIG. 2, reference numeral 30 indicates the entire numerical controller. The numerical control device 30 includes an operation unit 32 that analyzes an input machining program 31 to calculate a command, a program storage unit 33, and a memory unit 34 in which a correction data table 50 described later is stored. I have. The program storage unit 33 stores a tool length correction program for executing a function of correcting a tool length offset together with an OS program and a numerical control program. The numerical controller 30 analyzes the machining program 31 by executing the numerical control program and sends a command calculated and transmitted to the machine-side servo drive unit 36 via the input / output interface 35, and the servo drive unit 36 receives the command based on the command. , Y-axis motor 38, Z-axis motor 39, A-axis motor 40, B-axis motor 41, and C-axis motor 42. The control loop for performing feedback control of the position and the like is not shown because it has no direct relation to the tool length correction.
[0018]
As a tool length correction function realizing means that functions by executing the tool length correction program and the numerical control program, a correction vector is decomposed into a Z-axis direction and an X-axis direction having no control axis, and correction in the X-axis direction is performed. A correction amount calculating means 44 for simulating the amount from the C-axis correction amount and the Y-axis correction amount, and correcting the Z-axis movement based on the Z-axis correction amount and the C-axis correction amount. , A correction means 45 for simultaneously adding a correction amount for the Y axis, and a command means 46 for giving a corrected movement command to the control means for each axis.
[0019]
Hereinafter, functions corresponding to the tool length correction amount calculation means 44 and the correction means 45 according to the present embodiment will be described in detail.
FIG. 3 is an explanatory diagram of a correction vector used for tool length correction. In FIG. 3, reference numeral 102 is a pitch angle line of the blade of the propeller, and θ is the pitch angle of the propeller. The Y axis is perpendicular to the plane of the drawing. The reference plane of the pitch angle of the blade of the propeller is set to be the same plane as the XY plane, and the correction vector V is set in a direction perpendicular to the pitch angle line 102, and the magnitude is a correction amount, and the tool length is Offset. For each tool used for machining the propeller, an actually measured tool length is obtained for tool length offset for use in the machining program, and is registered together with the tool number. In FIG. 1, such tool data 49 is registered as a tool correction data table 50 in the memory unit 34 inside the numerical controller 30. In the tool correction data table 50, the value of the pitch angle θ of the propeller is also registered.
[0020]
The correction vector V is decomposed in the Z-axis direction and the X-axis direction.
The Z-axis component Vc and the X-axis component Xc of the correction vector are Vc = Vcos θ
Xc = Vsin θ
It is.
[0021]
The linear axes actually possessed by the 5-axis propeller processing machine are the Y-axis and the Z-axis, and there is no X-axis. Therefore, as shown in FIG. 4, the X-axis component Xc is converted into the C-axis movement amount.
[0022]
In FIG. 4, R is the distance from the center of the C axis to the machining point, and the movement amount (rotation angle) of the C axis at this time is θc.
θc = tan-1 (Xc / R)
It is.
[0023]
When the X-axis component Xc is converted into the C-axis movement amount, an offset is generated by Yc and the cutting point is shifted, so it is necessary to take a correction amount for Yc in the Y-axis direction. here,
Yc = R (1-cos θc)
It is.
Therefore, the correction amount for each axis is
Z-axis direction correction amount Vz = Vc
Y-axis direction correction amount Vy = Yc
C axis direction correction amount = θc
The correction amount is determined in the form of adding the correction in the Y-axis direction and the C-axis direction to the correction in the Z-axis direction.
[0024]
Such a tool length correction is described by a command using H and G codes in a machining program. Then, when the block having the correction command is read by the numerical controller 30, a tool length correction program is executed. That is, the value of the correction amount V and the pitch angle θ of the propeller are read from the correction data table 50, and the above-described Z-axis direction correction amount Vz, Y-axis direction correction amount Vy, and C-axis direction correction amount θc are calculated. The correction amount of each axis is algebraically added to a block having a Z-axis command, including a block having a correction command.
[0025]
Thus, every time the Z-axis command is executed, a command to move in the Z-axis direction by an amount corrected by the correction amount Vz, a command to move in the Y-axis direction by the correction amount Vy, and a command to rotate the C-axis by θc Are simultaneously generated, and these commands are sent to the servo drive unit 36.
[0026]
FIG. 5 is a plan view showing the propeller 100 from above to explain the movement in the Y-axis direction and the C-axis direction due to the above-described tool length correction. The direction perpendicular to the paper is the Z-axis direction. The center of the propeller 100 coincides on the C axis.
[0027]
The servo drive unit 36 controls the Z-axis motor 39, the Y-axis motor 38, and the C-axis motor 42 based on the transmitted command to move the tool in the Z-axis direction, and at the same time, as shown in FIG. Since the tool is rotated by θc and the tool is moved by Vy in the Y-axis direction, correction in the direction perpendicular to the pitch angle line 102 can be executed without shifting the cutting point K.
[0028]
Here, FIG. 6 is a diagram showing a cross section of a blade of the propeller 100 that is machined with tool length correction according to the present embodiment. The dashed line indicates the casting surface, and the solid line indicates the finished surface.
According to the tool length correction of the present embodiment, the correction vector V is taken perpendicular to the pitch angle line 102, the correction vector V is decomposed in the Z-axis direction and the X-axis direction, and the correction amount in the X-axis direction is corrected for the C-axis. The tool length correction can be applied perpendicularly to the pitch angle line 102 because the length and the correction amount of the Y axis are simulated from the amount and the correction amount of the Y axis. The correction amount can be made uniform regardless of the position. As a result, the cutting allowance d required for cutting from the cast surface to the finished surface of the blade does not fluctuate due to the variation in the correction amount, so that the blade can be processed with higher accuracy.
[0029]
In the above description, the A-axis is not tilted. In FIG. 6, when the A-axis is tilted by θA, the correction amount is calculated as follows.
[0030]
In FIG. 6, Vc obtained by decomposing the above-described correction vector in the Z-axis direction is inclined by θA due to the inclination of the A-axis. Therefore, Vc is decomposed in the Z-axis direction and the Y-axis direction. Then,
Z-axis component = Vc / cos θA
Y-axis component = Vc * tan θA
Because
Z-axis direction correction amount Vz = Vc / cos θA
Y-axis direction correction amount Vy = Yc + Vc * tan θA
C axis direction correction amount = θc
Then, the correction amount may be calculated.
[0031]
As described above, the present invention has been described with reference to the preferred embodiment of processing of a propeller used for a propulsion device of a ship. Is possible.
[0032]
【The invention's effect】
As is apparent from the above description, according to the present invention, the tool length correction can be applied perpendicular to the pitch angle line of the blade, and the processing point can be set on the blade surface regardless of the size of the pitch angle of the propeller. Since the correction amount can be made uniform at any position, the required cutting allowance does not change due to the variation in the correction amount, so that the blade can be processed with higher accuracy.
[Brief description of the drawings]
FIG. 1 is a front view showing a five-axis machine to which the present invention is applied.
FIG. 2 is a block configuration diagram of a numerical control device of the 5-axis machine according to the embodiment of the present invention.
FIG. 3 is an explanatory diagram of a correction vector used for tool length correction.
FIG. 4 is an explanatory diagram of a concept of creating an X-axis component of a correction vector in a pseudo manner.
FIG. 5 is a plan view showing movement of a blade of a propeller at the time of tool correction.
6 is a sectional view taken along the line VI-VI in FIG. 5, and is an explanatory view showing a casting surface and a finished surface of a blade of a propeller.
FIG. 7 is an explanatory diagram showing the concept of conventional tool correction.
FIG. 8 is a view for explaining the cause of the occurrence of residual shaving due to conventional tool correction.
[Explanation of symbols]
2 Bed 4 Column 6 Cross rail 8 Saddle 10 Spindle head 12 Table 30 Numerical controller 100 Propeller 102 Pitch angle line

Claims (4)

Consists of a linear axis (Y axis, Z axis), a pivot axis of the main axis (A axis, B axis), and a rotation axis (C axis) on the rotation center of a workpiece having a blade having a pitch angle. In the numerical control device of the spindle machine,
A correction vector having a magnitude corresponding to a correction amount for offsetting a tool length is set in a direction perpendicular to a pitch angle line of the blade of the workpiece, and the correction vector is defined as a Z-axis direction and a control axis. Correction amount calculating means for decomposing the correction amount in the X-axis direction, and calculating the correction amount in the X-axis direction from the C-axis correction amount and the Y-axis correction amount in a pseudo manner;
Correction means for correcting the Z-axis movement based on the Z-axis direction correction amount, and simultaneously adding the C-axis correction amount and the Y-axis correction amount correction;
A numerical control device for a five-axis processing machine, comprising: The workpiece is a fixed pitch propeller, and the reference vector of the pitch angle of the blade of the fixed pitch propeller is coplanar with the XY plane, and the correction vector is taken in a direction perpendicular to the pitch angle line. The numerical control device for a five-axis machine according to claim 1, wherein 2. The apparatus according to claim 1, wherein when the tool is inclined with respect to the A-axis, the Z-axis component of the correction vector is decomposed into a Z-axis component and a Y-axis component corrected by the inclination angle of the A-axis. Numerical control device for 5-axis machine. 5-axis machine composed of linear axes (Y-axis, Z-axis), turning axes of main spindles (A-axis, B-axis), and a rotation axis (C-axis) on the center of rotation of a fixed pitch propeller as a workpiece A numerical control device having a tool correction function of applying a correction amount for offsetting a tool length in the Z-axis direction,
The reference plane of the pitch angle of the blade of the fixed pitch propeller is coplanar with the XY plane, and a correction vector having a size corresponding to the correction amount for offsetting the tool length is defined as a pitch angle line of the blade. Taking the correction vector in the vertical direction, the correction vector is decomposed into the Z-axis direction and the X-axis direction of the X-axis having no control axis, and the correction amount in the X-axis direction is corrected by the C-axis correction amount and the Y-axis correction amount. A function to simulate the amount and
A correction function for simultaneously performing correction in the Z-axis direction and simultaneously performing correction in the C-axis and Y-axis;
A numerical control device for a five-axis processing machine, comprising:

Images