JPH055633B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a program that enables continuous and automatic machining of different finished outer diameters using a numerically controlled machine tool such as a numerically controlled grinder or a numerically controlled lathe. The present invention relates to a feed control device for numerically controlled machine tools having functions. More specifically, even in sizing machining where the feed is controlled based on sizing signals from a sizing device, multi-stage machining speeds are used according to a preset program depending on the location to be processed and the type of workpiece. The present invention relates to a feed control device that can automatically vary the machining width.

Conventionally, when performing processing such as grinding or cutting on a multi-stage workpiece whose finished outer diameter differs depending on the processing location using the above-mentioned sizing processing, an outer diameter measurement sensor was used to measure the outside of the workpiece being processed. The diameter is measured and this data is fed back to a numerical control device to control the diameter to a predetermined size. The sensor that measures the outer diameter consists of a pair of contacts, and is equipped with a mechanism that can change the distance between the contacts depending on the finished outer diameter of the workpiece, and a pulse motor that drives this mechanism. Controlled by a control device. In this way, the outer diameter measurement sensor changes the contact spacing according to the finished outer diameter dimension, so it is always possible to measure the outer diameter deviation based on the finished outer diameter dimension. Therefore, even when cutting and grinding a workpiece having multiple outer diameters, the machining width can be measured with the same precision, regardless of the outer diameter dimensions. In one machining location, the machining speed is usually controlled in multiple stages. In other words, it controls rough grinding, fine grinding, and fine grinding,
As the finished dimensions were approached, precision grinding was performed to achieve the optimum balance between surface finish accuracy and machining speed. For this purpose, the signal output from the outer diameter measurement sensor is compared with a predetermined reference value, and the result is input to a numerical control device to control switching of the machining speed.

However, in the conventional apparatus, the means for setting the switching position of the machining speed is configured to be set using a dial from the outside using a potentiometer or the like.
For this reason, when grinding into a multi-step shape according to a predetermined program, the position at which the machining speed is switched is always fixed. In other words, the machining width at each machining speed is
It remained constant. Therefore, depending on the processing location,
Alternatively, machining speed and surface finishing accuracy could not be freely controlled depending on the type of workpiece. If the accuracy of the surface finish were to be changed depending on the location to be machined, it would be necessary to reset the setting value of the potentiometer from the outside depending on the location to generate the reference value. . This completely negates the advantage of a numerical control device that automatically controls continuously.

Therefore, the present invention has been made in order to improve such conventional drawbacks.The present invention has been made in order to improve such conventional drawbacks. Among the numerical control data, the machining speed switching position data is
The data is outputted according to the machining location and the workpiece and used as reference data for switching the machining speed. That is, the present invention provides an outer diameter sensor that has a pair of contacts that come into contact with the outer diameter of a workpiece that has a multi-stage machining location, and that outputs an electrical signal in accordance with the deviation of the contacts from a reference position; A drive device that sequentially adjusts the distance between the two contacts according to the finished dimensions of each machining location and moves the reference position of the contacts; a sizing device comprising a sizing control section that compares with a plurality of reference signals and outputs a judgment signal for switching machining speed; and a sizing device that inputs a judgment signal from the sizing control section of the sizing device and performs the judgment. and a numerical control device that outputs control signals to control the machining process according to a set program in accordance with the signals and control data inputted in advance to continuously machine the plurality of machining locations of the multi-stage shape. The control device includes an output means for selecting and outputting grinding (cutting) feed start position data serving as machining speed switching position data from the control data for each of the machining locations. , the sizing control section is characterized in that it has a reference signal generating means that sequentially generates the reference signal for each of the machining locations based on the machining speed switching position data output from the output means. It is something.

Here, the workpiece is mainly a cylindrical rotating body, which has a different outer diameter and a different finished surface accuracy depending on the location to be machined. Or when machining multiple workpieces in succession,
This is a workpiece for which you want to finish the surface according to the material. The above-mentioned sensor is a position electric transducer that outputs an electric signal according to the outer diameter of the workpiece being processed. The sizing control unit that compares a plurality of predetermined reference signals with the signal output from the sensor and outputs a judgment signal when the values are equal is a comparator if it is an analog circuit, or a digital If it is a circuit, it can be constructed using a program-controlled microcomputer or the like. The above-mentioned numerical control device has a central processing unit (CPU) that performs predetermined control and calculations, a main storage device that stores predetermined data or control programs, an external storage device accompanying this, and the like. Then, the tool is fed based on a predetermined program and numerical control data, or
It outputs a signal that controls the feed of the table that supports the workpiece or the interval between the contacts that are the outer diameter measurement sensors. Further, the numerical control data is data necessary to control the above-mentioned processing.
The data is organized into data groups depending on the location to be machined or the type of workpiece. One data group includes, for example, numerical data such as table index position, final finishing dimension, rapid feed speed, processing speed switching position, and the like. In the present invention, among this numerical control data, the machining speed switching position data specified by the machining location is outputted to the aforementioned sizing control section according to the machining location, and the sizing control section: A reference signal is generated based on that signal. The sizing control section compares the measurement signal output from the contact with this reference signal and outputs a determination signal to the numerical control device. Since the program is controlled in this manner, the machining speed switching position can be arbitrarily selected depending on the location to be machined even during fixed-size machining, and therefore cutting can be performed in accordance with the location to be machined. Furthermore, the machining mode can be continuously and automatically varied depending on the type of workpiece.

Hereinafter, the present invention will be explained in more detail based on specific examples.

FIG. 1 is a block diagram showing the overall structure of a numerically controlled machine tool using the feed control device of the present invention.
The feed control device mainly includes a sizing device including an outer diameter sensor 30 and a sizing control section 20, and a numerical control device 10 into which a determination signal output from the sizing control section is input.
It consists of. The output from the numerical control device 10 is sent to the drive device 5 via the pulse generation circuit 14.
Servo motors 41, which are actuators, are output to 0, 51, and 52, and are connected to each of them.
64, 31, etc. The drive device 50 drives the servo motor 41 to move the grindstone head 40 in the X-axis direction and controls the feeding of the grindstone wheel 42 . The drive device 51 drives a servo motor 64 to drive the table 6.
5 in the Z-axis direction to control the selection of the machining location on the workpiece. The drive device 52 drives the pulse motor 31 disposed on the outer diameter measurement sensor, and controls the contact spacing according to the finished outer diameter. The workpiece 60 is centrally supported by a tailstock 62 and a headstock 66 and rotated by a spindle drive motor 61 .
On the other hand, the outer diameter measurement sensor 30 has a pair of contacts and an actuating transformer that converts the deviation of the contacts with respect to the reference position into an electrical signal, and the output thereof is sent to the sizing control section 2.
Enter 0. The output is amplified by an amplifier 25 and then input to each non-inverting input of comparators 23a, 23b, and 23c. On the other hand, a reference voltage is applied to the inverting input terminals of these comparators. Predetermined data corresponding to the machining location output from the numerical control device is program-controlled and latched into latch circuits 21a and 21b. The latched digital data are converted into analog voltages by digital-to-analog converters 22a and 22b, and inputted as respective reference voltages to the inverting inputs of the comparators. The outputs of these comparators are input to the numerical control device 10. The numerical control device includes a central processing unit 11, an input/output interface 13, a main storage device 12, and input/output devices 15 and 1 for inputting data from the outside.
6, an external storage device 17.

Next, the operation in such a configuration will be explained. Predetermined data is input in advance to the main memory 12 of the numerical control device as shown in FIGS. 2a and 2b. Here, STB1 and STB2 indicate data blocks, which contain predetermined data that allow the machining speed to be changed and the surface finish accuracy to be changed depending on the location to be machined.
Further details of STB1 are stored in Figure 2b. Here, data such as table index position, final finished dimensions, rapid feed speed, etc. are input. Further, such data may be input from the external storage device 17 for each processing location.

In the present invention, as will be described later, among this data, Rfs and Rms data specified by the processing location are output to the sizing control section. Rfs, Rms
The meanings of the data such as , etc. are shown in FIG. That is, it shows the positions at which the machining speeds are switched based on the final finished dimension Re. Rrs represents a rough grinding feed start position, Rfs represents a fine grinding feed start position, and Rms represents a fine grinding feed start position. FIG. 6 shows the relationship between the tool feed position and time when machining is performed according to this program. FIG. 3 shows a flowchart of the control program of the numerical control device.

This program mainly consists of three subroutines. That is, subroutine 100 performs pulse distribution processing for table indexing. The table supporting the workpiece is slid to a predetermined position, thereby setting the machining location on the workpiece. Subroutine 200 is a routine that performs pulse distribution processing for the NC sizing device. That is, the interval between the contacts of the sizing device is moved to a predetermined position based on finished outer diameter dimension data corresponding to the machining location. By doing this, a constant machining width can be measured with the same accuracy, regardless of the final finished dimensions, even for items with multiple diameters. subroutine
Reference numeral 300 performs a pulse distribution process for grinding, and by this process, the workpiece is finished by grinding in a predetermined manner. Then, when the process moves to determination step 400, if there is still a part to be machined on the workpiece, the process returns to the initial position and sets the next part to be machined and grinds it.

FIG. 4 provides a more detailed explanation of the subroutine 300. When entering this subroutine, the machining location has already been set.
In step 301, select the data block corresponding to the machining location and input the grinding feed speed switching position data.
Outputs Rfs and Rms to the sizing control section. The sizing control section generates a reference voltage based on this data. Steps 302 and 304 are steps for rapidly feeding the tool to a predetermined position. As a result, the servo motor 41 is driven and the tool is rapidly fed from the starting point (Po) to the _P1 point as shown in FIG.

Next, in step 306, a rough grinding feed rate is set based on the above data. Next, in step 308, counter C is set to the initial value for rough grinding.
Set the value of Rrs. In step 310, the tool feed is processed one unit at a time based on the above data. This drives the servo motor 41 and moves the workpiece one step at a time. In the next step 312, it is detected whether the determination signal AS1 signal is on or not. Here, the judgment signal means that the sizing control unit 20 determines that the signal measured by the pair of contacts is a predetermined reference signal, that is, in this case, according to the data of the position Rfs at which to switch to fine grinding. This is a signal that is compared with a reference voltage and is output from the comparator 23a to the numerical control device when it becomes equal to the reference value. The same applies to the determination signals of AS2 and AS3 below. Until this AS1 signal is detected
It is supposed to return to step 310 and repeat in sequence. For this purpose, the workpiece is ground with a predetermined coarse grinding feed rate to the next switching position. Here, steps 314, 316, and 318 are measures to prevent runaway tool feeding. That is, in step 314, the value of the counter is subtracted one unit at a time, and when the value of the counter reaches near the position of Rfs at which the grinding speed is switched, the process is stopped. Here, α indicates an allowable range for security. If the grinding exceeds the allowable value, abnormality processing is carried out in step 318 and the machining process is stopped. In this way, runaway tool feed due to detection errors by the sizing device is prevented.

Next, a process similar to the series of processes described above is performed from step 320 onwards. That is, in FIG. 6, rough grinding is performed from point _P1 to point _P2 , and then fine grinding is performed from point _P2 to point _P3 in steps 320 to 332. Further from step 332
In step 344, the tool is finely ground from point _P3 to point _P4 , and finally, in step 344, the tool is quickly returned to the initial position.

Next, after one location is worked in this way, the main program is returned to, the table is moved to a predetermined position, which is the next work location, and the next subroutine 200 performs the predetermined processing. .
In this way, according to the work location, in the present invention, data such as Rfs and Rms, which are data used for runaway safety, are output to the sizing control section according to each work location, and the sizing control section outputs this data. Generates a reference signal according to the Therefore, the feed cycle curve of the tool shown in FIG. 6 is not fixed, but can be arbitrarily and automatically adjusted depending on the location to be machined. Further, it can be arbitrarily selected depending on the type of workpiece.

In summary, the present invention outputs data that gives the switching position of the machining feed rate of a tool, which is input to a numerical control device for security purposes, to the sizing control section according to each work location. generates a reference voltage according to the data, compares it with the measurement signal measured from the outer diameter sensor, and feeds back a judgment signal to the numerical control device. Then, the numerical control device can arbitrarily switch the machining speed of the tool based on this determination signal. Therefore, according to the apparatus of the present invention, even in the case of a workpiece having multiple diameters, the surface finishing accuracy and machining speed can be arbitrarily selected depending on the location to be machined. Therefore, it has the effect of extremely high processing efficiency. In addition, this feed control device uses the speed switching position data stored in the numerical control device of the numerically controlled machine tool for security purposes as data for changing the sending timing of the judgment signal. This has the great effect that the numerical control program does not become complicated even if the timing at which the determination signal is sent is changed for each processing location.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the specific structure of a feed control device and the entire structure of a numerically controlled machine tool according to the present invention. Figures 2a and 2b are data charts showing blocks of input data used in the above embodiment. FIG. 3 is a main program showing the processing of the numerical control device. FIG. 4 is a flowchart regarding the grinding process of the main program. FIG. 5 is an explanatory diagram illustrating data indicating the machining speed switching position. FIG. 6 is a machining cycle diagram in which the machining speed can be changed. 10... Numerical control device, 20... Sizing control section,
30... Outer diameter sensor, 40... Grindstone head, 21a,
21b...Latch circuit, 23a, 23b, 23c
……comparator.

Claims (1)

[Scope of Claims] 1. An outer diameter sensor that has a pair of contacts that come into contact with the outer diameter of a workpiece having a multistage machining location and that outputs an electrical signal according to the displacement of the contacts from a reference position. , a drive device that sequentially adjusts the distance between the two contacts according to the finished dimensions of each processing location and moves the reference position of the contact; and a drive device that uses the electrical signal input from the outer diameter sensor to switch the processing speed. a sizing device comprising a sizing control section that compares data with a plurality of reference signals and outputs a judgment signal for switching the machining speed; a sizing device that receives a judgment signal from the sizing control section of the sizing device; a numerical control device that outputs a control signal to control a machining process according to a set program in accordance with the judgment signal and control data inputted in advance, and to continuously machine a plurality of machining locations of the multi-stage shape; The numerical control device includes a storage device that stores control data such as finish dimensions, feed speed, rough grinding and fine grinding feed start positions, etc. for each of a plurality of processing locations, and a storage device that stores control data such as finish dimensions, feed speed, rough grinding and fine grinding feed start positions, and the like. an interval control means for controlling the drive device by selecting finishing dimension data according to the machining location from the stored control data; and grinding feed start position data serving as machining speed switching position data from the control data. The sizing control unit selects and outputs the reference signal for each of the processing locations based on the processing speed switching position data output from the output means. A feed control device for a numerically controlled machine tool, characterized in that it has a reference signal generating means that sequentially generates a reference signal.