JPH0354606A - Numerical controller - Google Patents

Abstract

PURPOSE:To effectively use a memory without necessitating the individual storage of data at an air-cut part by performing the synchronous control of the air-cut part by using part of existing data of shape to be worked repeatedly. CONSTITUTION:A memory device which stores the shape to be worked equivalent to the multiple rotation of a main shaft as a data table 1, and a readout means 14 which reads out the data equivalent to one time of rotation of the main shaft at the forefront of the data table 1 repeatedly when performing air-cut before working and reads out the data in the data table 1 sequentially when performing the working and the data equivalent to one time of rotation of the main shaft at the most rear part of the data table 1 repeatedly when performing the air-cut after working are provided. Thereby, since no re-generation of all data tables 1 is required even when the quantity of air-cut is changed, man-hours can be remarkably reduced, and also, since no data at the air-cut part is required, no memory large in capacity is required, which reduces the cost of an NC device itself.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an NC device that synchronously controls the rotation angle of a main shaft of a numerically controlled (hereinafter referred to as NG) lathe and the like and the position of a feed shaft.

(Prior art) When performing thread cutting by synchronously controlling the rotation angle of the main spindle and the position of the feed axis, the ratio of the rotation angle of the main spindle and the feed rate of one feed axis is generally constant, so the NC Only simple proportional calculations are performed inside the device, and the calculation process can be completed in a short time. However, if the rotation angle of the spindle and the position of the feed axis are defined by a complicated functional formula, the calculation process will take a long time, making it difficult to realize synchronous control in real time. In such a case, an NG device is used which has means for storing in advance the rotation angle of the main shaft and the position of the feed shaft, which are determined separately. According to this IIIc device,? Since there is no need to subtract in real time even if complicated function formulas or interpolation formulas are used, there is no longer a limit on calculation processing time, and turning processing can be performed at the same rotational speed as the main spindle during simple thread cutting. can be done.

FIG. 5 is a block diagram showing an example of the conventional NG device described above, which includes a main shaft pulse generator (PG) 8 that detects the rotation angle of the main shaft 7, and an upper shaft P.G. G. Among the pulse signals generated by 8, the marker pulse is used as the starting signal ^. A pulse counter 9 that counts B-phase pulses, and a latch that reads the current position of the feed shaft driven by the servo motor 6 via the position detector 10 and the counter 1.1 based on the current position read signal from the pulse counter 9. circuit l
2, and the main axis P. G. It has a data table 1 for position command values in which position command values of the feed axis corresponding to each pulse of one rotation of the main shaft are generated and stored in advance off-line by a leap number. Furthermore, a subtracter 2 that uses the table address signal from the pulse counter 9 as a control timing to subtract the position command value read from the position command value data table l and the current position from the latch circuit 12 to obtain a position deviation value; A D/^ converter 3 that controls the servo motor 6 using the position deviation value from the subtracter 2 to synchronize the position of the feed axis and the rotation angle of the main axis. analog gain amplifier 4
and a servo amplifier 5.

A case will be described in which, for example, a non-round piston for an internal combustion engine shown in FIG. 6 is processed using the NG device having such a configuration. The solid line at the bottom of the figure is an exaggerated depiction of the non-perfect circular shape of a piston for internal combustion engines, and the diameter of the solid line at the top part is smaller than the diameter of the solid line at the skirt part. This means that the outer diameter of the piston is tapered.

First, as shown in Fig. 7, a helical trajectory is calculated in advance using the feed amount F during actual cutting and the number ilJ divided into one spindle rotation, and is stored as a data table. (Workpiece) is fixed to the main shaft by a tailstock as shown in Fig. 8. And in the longitudinal direction (2@
) and the diametrical direction (X-axis), (^) ~ (G
) Machining is executed in the order of process numbers. Process number (8) ~
In (G), the data table is used as shown in the time chart of FIG. Here, the main erection PG marker pulse is the PG marker pulse attached to the main shaft. This is one of the pulses that is generated, and is a pulse signal that occurs once per main rotation.

In addition, the data table numbers are sequentially numbered 1, 2, etc. for each rotation of the spindle for position command value data corresponding to multiple rotations of the spindle.
If this position command value data consists of 360 pieces of data for every 1 degree per rotation of the spindle, each data table number will contain all 360 position command values. It is made up of data.

The operation of the NG device will be explained below in order of process number. （＾）
The tool fixed to the tool post is positioned at the starting position (x., z0) while the rotation of the spindle is stopped.

(B) Position the tool at the cutting start point (x+.z+) in rapid traverse and rotate the spindle.

(C), (D). (E) Feed amount F specified for Z axis
The actual cutting start point (
X2. Air cut to Z2) and actual cutting start point (X2)
．． Turning from Z2) to the actual cutting end point (X3, Z3) and air cutting to the cutting end point (x4, zJ) are executed.

(F) When the tool reaches the cutting end point (x4.Z<), Zi
Stop the movement of PIil and X axis.

(G) Stop the rotation of the spindle and retreat the tool to the retreat position (Xs.Zs) in preparation for the next program command.

(Problems to be Solved by the Invention) The above-mentioned conventional NC device also performs k rotations of the spindle and 2
Since it has a data table corresponding to rotations, the total data table number will be kin + angle if the actual cutting part is a data table corresponding to n rotations of the spindle.

For example, the longitudinal dimension of the internal combustion engine piston described above is 7 L-6.
0+am, feed amount F-0.1mm/n,, if we have a pitch data table with spindle rotation angle P=1, the number of data is N. is expressed by the following equation (1), so the number of data for the actual cutting portion is 216,000.

NO- 360 XL / (FX I')
・・・・・・・・− (+) Then, if we take the air cut portions of 5 ml before and after the internal combustion engine piston, the number of data will be 35,000 from the above formula (1), and a total of 252,000 data will be required. Become. If one piece of data is expressed in 4 bytes, the total amount of data will be 1,008,000 bytes, which means that almost one 8-inch floppy disk will be used just for data on the outer diameter shape of a piston for an internal combustion engine.

Despite the huge amount of data, with conventional NC devices, when changing the amount of air cut, the entire data table must be recreated, which takes a long time and makes it difficult to perform the actual cutting process. This had the disadvantage of requiring a large amount of memory, as it required the data of the air cut for the non-lever to be memorized.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to eliminate the need to recreate the entire data table even if the air cut amount is changed, and to eliminate the need for data on the air cut portion. The purpose of the present invention is to provide an NC device.

(Means for Solving the Problems) The present invention relates to an NC device that synchronously controls the rotation angle of the main spindle and the position of the feed axis of an NG machine tool, and the above object of the invention corresponds to multi-rotation of the main spindle. a storage means for storing the machining shape to be processed as a data table; during air cutting before machining, data corresponding to one rotation of the main spindle at the beginning of the data table is repeatedly read; during machining, the data in the data table is sequentially read; When air cut C
This is achieved by comprising a reading means for repeatedly reading out data corresponding to the last king flIl1 quadruple of the data table.

(Operation) The NG device 2 of the present invention converts a part of the existing machining shape data into 1/j. Since the air cut section is synchronously controlled by using the air cut section, there is no need to store data for the air cut section separately, and memory can be used effectively. Example) FIG. 1 is a block diagram showing an example of the NG device of the present invention in correspondence with FIG. 5, and the same parts are given the same reference numerals and the explanation will be omitted. This NC device is a data read controller l that reads data from the position command value data table 1.
4 has been newly established. This data successive controller l4 operates in four data read states (1) to (4) described below.

■A state in which the data in the first data table number of the data table for position command values is used repeatedly.

■A state in which the data in the position command value data table is used in the order of the data table number.

■A state in which the data in the last data table number of the data table for position command values is used repeatedly.

■Stopped state. In this case, the data immediately before stopping becomes valid.

In such a configuration, an example of its operation will be described with reference to the flowchart of FIG. 2 and the time chart of FIG. 3 for machining the piston for an internal combustion machine described in the conventional example.

(A) Position the tool post (fixed tool) at the starting position (X0, 20>) while stopping the rotation of the spindle.

(B) Position the tool at the cutting start point (x1, zl) in rapid traverse and rotate the spindle.

(C) Move Zeb at the specified feed fA F, and move the X-axis using the position command value data of the data table number synchronized with the main PG marker pulse generated by the rotation of the main axis (step S1) . At this time,
21fiIL with the best air performance up to the starting point of Jitukiri/41J (X2.22). is input as a command on the cutting program, and the data of data table number "1" is inputted. /F times of repeated use, step S2. S3
). (D) From the actual cutting start point (X2, Z2) to the actual cutting end point (
X3. Perform turning processing up to Z3). That is, z−z
Number of rotations of the main shaft corresponding to position 2 {,. Rotate the spindle by /F and use the data in data table number order 1.23... Step 54, S5). (E) End of cutting +g. Perform an air cut up to (x4.z.+). In other words, if the number of rotations of the spindle corresponding to Z-Z= is set as n, then the data table number will be changed from the point at which n is exceeded.
n'' data is used repeatedly (step S6.57
).

(F) When the tool reaches the cutting end point (X4, Z4), stop the movement of the Z axis and X@.

(G) The rotation of the spindle is stopped, the tool is evacuated to the retraction position (Xs.Zs) in preparation for the next program command (step S8), and all processing is completed. Figure 4 (8) and (
B) is a block diagram showing another example of the data succession controller 14.

In the data successive controller l4 shown in FIG. A position command value from a function generator 142 that performs position control such as tool retraction, rapid forwarding, etc. is sent to an adder 143, and a new position command value is output. According to such a configuration, xi can be moved away from or approached the processing position during synchronous control.

In the data read controller 14 shown in FIG. 4(B), the switch SW144 is set to the "1'" side during synchronous control, and data from the data table 1 storing absolute position command values is output. Switch 1 when other than
44 is on the "2" side, and the position command value before the start of synchronous control from the function generator 145 is output.

(Effects of the Invention) As described above, according to the NG device of the present invention, even if the air cut amount is changed, there is no need to recreate all data tables, so it is possible to significantly reduce the number of man-hours, and Since the data of the cut portion is unnecessary, a large-capacity memory is not required, and the cost of the NG device itself can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the NC device of the present invention, FIGS. 2 and 3 are flow charts and time charts explaining an example of its operation, and FIG. 4 (^) (8) is a block diagram showing an example of the NC device of the invention. A block diagram showing another example of the main parts of the device,
Fig. 5 is a block diagram showing an example of a conventional NG device;
The figure is a perspective view showing a specific example of the workpiece, Figure 7 is a diagram explaining the data table of the workpiece shown in Figure 6, Figure 8 is a diagram showing the processing process of the workpiece shown in Figure 6, and Figure 9 is a time chart illustrating an example of the operation of a conventional NG device. 1... Data table for position command value, 2... Subtractor, 3... D/A converter, 4... Analog gain amplifier, 5... Servo amplifier, 6... Servo motor, 7
...Main axis, 8...Main IThIIP. G. ,9
...Pulse counter, lO...Position detector, 11.
... Counter, l2... Latch circuit, l4... Data read controller, 141, 144... Switch,
143... Adder, 142, 145... Function generator.

Claims (1)

[Claims] 1. In a numerical control device that synchronously controls the rotation angle of the spindle of a numerically controlled machine tool and the position of the feed axis, there is a storage means that stores the machining shape corresponding to multiple rotations of the spindle as a data table, and a storage means that stores the machining shape corresponding to multiple rotations of the spindle, and Repeatedly reading data corresponding to one revolution of the main shaft at the beginning of the data table,
During processing, the data in the data table is read out sequentially,
A numerical control device comprising: reading means for repeatedly reading data corresponding to one revolution of the spindle at the end of the data table during air cutting after machining.