JPH03277445A - Control device for numerical control(nc) machine tool - Google Patents

Abstract

PURPOSE:To machine a workpiece on simple data about machining, by taking out specified cross sections, tracing the cross section forms to detect the form data of the cross sections, finding a cutting quantity from the differences between the detected data and the data of designed cross sections, and using the characteristics of machining a curved surface with uniform cross sections. CONSTITUTION:A detecting means 6, tracing the specified cross section forms of a workpiece 4, detects the form data of the cross sections. Then input is provided by an input means with the data of designed cross section forms and the positions of setting to the workpiece 4 as many cross sections as correspond to the size of the work piece 4 parallelly to the specified cross sections. Then a calculating device 9 makes differences in data between the cross section forms detected by a detecting device 6 and the designed cross sections inputted by the input means, finding a cutting quantity of each cross section form position. To the cross section setting positions inputted by the input device, the cross sections are set, which are outputted to a NC tool machine 1 so as to use the cross sections and the cutting quantities previously found for the specified cross sections. This enables the easy procurement of data for machining a curved surface with uniform cross sections.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a control device for a numerically controlled (NC) machine tool, and in particular to an NC machine that cuts a curved surface with a similar cross-sectional shape. Regarding machine control devices.

(Conventional technology) NC processing of curved surfaces such as propellers and guide blades of power generation water turbines
When using a machine tool, a computer is used to obtain NC data as machining information based on the design drawings and design values of the workpiece, and this NC data is converted and returned to the operating amount for each NC axis of the NC machine tool. The cutting process is performed by controlling the position of the cutting blade according to this converted value.

(Problem to be solved by the invention) By the way, the creation of NC data necessary for NC processing of a workpiece having a three-dimensional curved surface, such as the guide vane of a water turbine, requires the development of advanced curved surface processing software and the application of computers. This is indispensable, requires data transfer work between the computer and the NC control device, and furthermore, during NC machining, it is necessary to set the workpiece with high precision, which requires a large amount of work time.

The present invention has been made in view of the above-mentioned problems, and provides a control device for an NC machine tool that is capable of cutting a curved object with a cross section by utilizing its characteristics and using simple processing information. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, a predetermined cross section is taken out, its cross-sectional shape is traced to detect cross-sectional shape data, and this cross-sectional shape data and design cross-sectional data are combined. The amount of cutting can be calculated from the difference, and the NC machine tool control device of the present invention can calculate the amount of cutting from the difference.
In a control device for an NC machine tool that performs dimensional cutting, there is a detection means that detects cross-sectional shape data by tracing the shape of a predetermined cross-section of a workpiece, and a detection means that detects cross-sectional shape data by tracing the shape of a predetermined cross-section of a workpiece, and a detection means that detects cross-sectional shape data and detects cross-sectional shape data on the workpiece according to its dimensions. an input means for inputting a position at which a cross section parallel to the predetermined cross sections is set; and a cutting amount at each position of the cross-sectional shape is calculated from the difference between the cross-sectional shape data detected by the detecting means and the designed cross-sectional shape data. The apparatus further comprises a calculation means for outputting a cutting amount as a cutting amount for each cross section whose position is input from the predetermined cross section and the input means, and the NC machine tool is controlled by the output of the calculation means.

(Operation) By tracing the shape of a predetermined cross section of the workpiece using the detection means, shape data of the cross section is detected. Next, using the input means, data on the cross-sectional shape determined by the design is inputted, and positions for setting a number of cross-sections corresponding to the size of the workpiece in parallel with the predetermined cross-section are manually set on the workpiece. The calculation means takes the difference between the cross-sectional shape data detected by the detection means and the design cross-sectional data inputted by the manual means, calculates the cutting amount at each position of the cross-sectional shape, and further sets the cross-section at the cross-section setting position inputted from the input means, The previously determined cutting amount is output to the NC machine tool as the cutting amount for this cross section and a predetermined cross section. This makes it possible to easily obtain machining data for cross-section-like curved surfaces.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 is a block diagram showing the configuration of this embodiment. The NC machine tool 1 controlled by the control device 5 of this embodiment has an X-axis and a Y-axis of an orthogonal coordinate system.

Performs movement in the Z-axis direction and rotation of the work table rotation axis 4
A cutting tool 3 such as a ball end mill is attached to a main spindle head 2 that is composed of axes and performs a combined operation of the X, Y, and Z axes. FIG. 2 is a detailed view of the ball end mill 3. The control device 5 includes a detection unit 6 that detects the amount of movement of each NC axis that has been taught by operating the NC machine tool 1 on the workpiece 4, and a detection unit 6 that attaches the amount of movement detected by the detection unit 6 to the spindle head 2. an arithmetic control section 7 that converts the motion of the tip of the cutting tool 3 into a motion target point; a storage section 8 that stores the motion target point computed by the arithmetic control section 7; and a motion target point stored in the memory section 8. a calculation unit 9 that calculates the amount of cutting based on the points;
It consists of a keyboard 10 for inputting design data necessary for the calculations of the calculation section 9, and a display 11 for displaying the calculation results of the calculation section 9.

Part 3 regarding the operation of the control device 5 configured as described above.
This will be explained using the flowchart shown in the figure.

Consider a power generation water turbine guide vane as the workpiece 4.

The water turbine guide vane 4 has a uniform wing-shaped cross section as shown in FIG. 4(a). First, in step 3J, the detection unit 6 operates the NC machine tool 1 along the teaching shape A shown in FIG. I will teach you one by one.

The operation amount of each NC axis with respect to the operation target point of the cutting tool tip obtained by the detection unit 6 by this teaching is calculated from the NC operation amount and the operation target point of the cutting tool 3 tip incorporated in the calculation control unit 7 in step 32. It is converted into an operation target point group by a mutual conversion algorithm with the 3D image and stored in the storage unit 8.

Next, in step 33, the motion target point P and the next motion target point P are selected from the keyboard 10 as shown in FIG. 4(a). A design that determines the number of divisions n to interpolate between 1, the interval 1 to set the cross section parallel to the cross section defined by the operation target points P1 to P at a constant interval in the Y-axis direction, and the cutting shape. Input data R2 to R, . FIG. 4(b) shows the relationship between the movement target point group P1-P and the design data R2-R0.

In step 34, the calculation unit 9 reads out the operation target points P, ~Pゎ stored in the storage unit 8, and reads out the operation target points P, ~Pゎ, which are stored in the storage unit 8, and calculates the curve A shown in FIG.
is expressed as a continuous and smooth cubic equation, and the number of division settings is n.

Interpolation operation target point groups QII to QIllIQ21 to Q2□ are the values of pitch n in the X-axis direction of each cross section set at intervals l using the interval l as shown in FIG. 5(a).

Q ml to Q tan are calculated, and the cutting amount Δd is obtained from the difference between the operation target point and the design point data as shown in FIG. 5(b), and this value is stored in the storage unit 8. This cutting amount △d−
The calculation method will be explained in detail using FIGS. 4 and 5.

A movement target point P, (x,,z,) and an adjacent movement target point P,. 1 (xl.2.zl.,) is defined as the i section, and the operation target point P i+2 (X ++2 ) adjacent to P 141 (X 141Z++1).

Let the interval of Find the coefficients al and bl that will make them equal, and calculate 2 for every interpolation width n in the X-axis direction. Find the value of Q. Similarly, target point P.

By performing the above steps, an interpolation operation target point sequence Qz to Q is obtained. In addition, for the design point data R1 to R, the curve B shown in Fig. 5(b) is obtained using the cubic spline interpolation formula in the same way as above.
Interpolation set point data 8 as a value of 2 for each axial interpolation width n
Find the 1 to So columns.

Next, the difference between the interpolation operation target point sequence Qz and the interpolation design point data S1 is determined as the cutting amount Δd. Similarly, the cutting amount sequence △d,
Find ~△d. Next, for interpolation of each cross section set at intervals l in the Y-axis direction, columns Q1□ to Q+n are translated in parallel in the y-axis direction at intervals of 1, and interpolation operation target point groups Q21 to Q are obtained. seek. Interpolation operation target point group Q1□~ obtained in this way
Qff111 is displayed on the display 11 in step 35, and it is determined in step 3 whether the result is satisfactory.
6, and if correction is necessary, press keyboard 10 again.
A newer set number of divisions n1 interval l is input, and the interpolation operation target point group Q1□ to Q is determined again by interpolation calculation, and the process is repeated until a satisfactory result is obtained. If the result is satisfactory, in step 37, the interpolation movement target groups Qz to Q are stored in the storage unit 8. and cutting amount groups △d1 to △d corresponding to these
, is read out, and converted into the movement amount of each NC axis using the conversion algorithm between the movement target point and the movement amount of each NC axis in the arithmetic control unit 7, and interpolated over the entire area of the water turbine guide vane 4 in step 38. Interpolation operation target point group Qz~Q,. Cutting is performed according to the cutting amount Δd1 corresponding to . Note that the interpolation operation target point group Qz~Q, . The method of converting the amount of operation of each NC axis differs depending on the configuration of the NC machine tool 1, so an appropriate conversion corresponding to the target NC machine tool may be performed.

As described above, according to this embodiment, by teaching the motion target point of a predetermined cross section of the workpiece having a --like machining cross section, the motion target point over the entire machining area of the workpiece can be determined. Even though the teaching work is simple, it is possible to perform the work continuously over the entire area to be processed. Further, since a group of interpolated operation points is determined from the taught target operation points and the cutting operation is performed continuously along this group of interpolated operation target points, it is possible to finish the machined surface smoothly. Furthermore, since the teaching work is simple, the time required for the entire work is shortened and the NC
The work efficiency of cutting can be greatly improved.

[Effects of the Invention] As is clear from the above explanation, according to the present invention, by teaching the motion target of a predetermined cross section of a workpiece having a different machined cross section, the motion target point of the entire machined surface can be calculated. All surfaces to be machined can be processed continuously, reducing working time and improving work efficiency.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a shape diagram of a ball end mill, Fig. 3 is a flow diagram showing the operation of this embodiment, and Fig. 4 is a diagram of a group of operation target points. Explanatory diagram,
FIG. 5 is an explanatory diagram of the interpolation operation target point group and the amount of cutting. 1...NC machine tool 2...Spindle head 3...
- Cutting tool 4... Workpiece 5... Control device 6... Detection section 7... Arithmetic control section
8...Storage unit 9...Arithmetic unit lO・
...Keyboard 11...Display application agent

Claims (1)

[Claims] In a control device for an NC machine tool that performs three-dimensional cutting, a detection means detects cross-sectional shape data by tracing the shape of a predetermined cross-section of a workpiece, and a detection means detects cross-sectional shape data by tracing the shape of a predetermined cross-section of a workpiece. an input means for inputting a position at which a cross section parallel to the predetermined cross sections is set; and a cutting amount at each position of the cross-sectional shape is calculated from the difference between the cross-sectional shape data detected by the detecting means and the designed cross-sectional shape data. A calculation means for outputting a cutting amount as a cutting amount of the predetermined cross section and each cross section whose position is inputted from the input means, and the NC machine tool is controlled by the output of the calculation means. Control device.