JPH11165241A - Work machining device on lathe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for machining a work in correspondence with a detection value by detecting the work without using a positional detector concerning a machining method of the work on a lathe. SOLUTION: A work detection member consisting of a rod material or a plate material of a simple shape is installed on a turret, collision of this work detection member and a work is detected by monitoring torque of a delivery motor of a tool rest and a spindle dividing motor, a coordinate of the tool rest and a phase of the spindle at the time are read by an NC device, and machining of the work is carried out in accordance with the read value. It is possible to set a machining standard position of the work, to set the number of rough machining and to set a dividing standard position at the time of spindle dividing machining in this method, and it is also possible to compute a machining standard from values such as an average value by making the work detection member contact with two points of the work. It is especially effective to us positional deflection of a servo control device to control the tool rest delivery motor and the spindle dividing motor for collision of the work detection member and the work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of processing a work performed by using a lathe, and a method of measuring dimensions of a work loaded on the lathe and processing the work based on the measured values. It is about the method.

[0002]

2. Description of the Related Art Cast and forged products have variations in the shape and dimensions of the work. When machining these, the position and feed of the blade at the time of starting processing according to the variation in the shape and dimensions. By setting the amount, processing can be performed efficiently and occurrence of defective processing can be reduced. In order to perform such processing, it is necessary to detect a processing start position or a processing reference position of a workpiece loaded on a lathe before starting processing.

In order to perform this detection, conventionally, a position detector is mounted on a turret of a lathe to detect the position of a work. This position detector has a structure in which a detection needle 44 is provided in a state in which it is electrically insulated from a holder 43 mounted on a turret 4 of a lathe as shown in FIG. Work 14 held in 3
When the contact is made, the work 14 and the detection needle 44 are electrically connected to each other, and it is determined that the detection needle 44 and the holder 43 are electrically connected to each other through the machine main body which is an electric conductor. The structure which detects with an electric device is adopted. When a contact signal between the detection needle of the position detector and the workpiece is sent to the NC device that controls the lathe, the position of the turret 4 and the phase of the spindle (at the time of performing the C-axis control of the spindle) ) Is recognized on the NC device side, and the processing start position and the processing reference position of the work 14 can be calculated from these values.

[0004]

The position detector 46 is mounted on the turret 4 and is indexed toward the work when performing work detection. When the work 14 is processed, a cutting tool or a drill mounted on the turret 4 is indexed to the work according to the processing mode. So usually,
The position detector 46 remains attached to the turret 4 even during the work processing. However, since the position detector 46 is an expensive precision device assembled with high accuracy, the position detector 46 is easily damaged by cutting oil and chips during processing. Generally, detection needle 4
Numeral 4 is provided movably on the holder 43 in order to absorb a slight overrun after coming into contact with the work 14.
Depending on the moving direction of the sensor 44, the shape of the detection needle 44 is restricted, or the detection position of the work is restricted.

It is an object of the present invention to provide a method of detecting a work loaded on a lathe without using an expensive position detector and processing the work in accordance with the detected value.

[0006]

According to a method for machining a workpiece in a lathe according to the present invention, a workpiece detecting member 12 made of a bar or a plate having a simple shape is mounted on a turret 4, and a collision between the workpiece detecting member and a workpiece 14 is performed. Is the feed motor 7 of the tool post,
8 is detected by monitoring the torque of the spindle motor and the spindle indexing motor, the coordinates of the tool rest and the phase of the spindle at that time are read by an NC device, and the workpiece is machined based on the read values.

According to the first aspect of the present invention, the above-mentioned means is used to determine a processing standard of a work. The work detecting member 12 is mounted on the turret 4 and the work 14 is mounted on a lathe.
With the output torque of the feed motors 7 and 8 moving the tool post 5 restricted, the tool post 5 was moved toward the work 14 while monitoring the load, and the load of the feed motors 7 and 8 exceeded the set level. The position of the tool rest 5 at that time is read by an NC device, a shift value is calculated based on a deviation between the read value and a preset reference value, and the coordinate value of the work machining program is shifted by this shift value. This is to control the position of the tool post 5 during processing.

According to a second aspect of the present invention, a work processing standard is set to 2
This is set based on the measured values of points. The work detection member 12 is mounted on the turret 4, the work 14 is loaded on the lathe, and the load is monitored while the output torque of the feed motor 7 moving the tool post 5 is limited. The tool post 5 is moved toward the workpiece 14 while the position of the tool post 5 when the load of the feed motor 7 exceeds the set level is read as the first coordinate by the NC device, and then the tool post 5 is moved backward. Or the position of the workpiece detection member 12 is changed to move the tool rest 5, and the position when the load of the feed motor 7 exceeds the set level is read as the second coordinate by the NC device, and the first coordinate and the second coordinate are read. The shift value is calculated based on the two coordinates, and the coordinate value of the workpiece machining program is shifted by the shift value to control the position of the tool post 5 during the workpiece machining.

According to a third aspect of the present invention, a feed motor for setting the number of times of rough machining of a workpiece is provided. The workpiece detecting member 12 is mounted on the turret 4, the workpiece 14 is loaded on the lathe, and the tool post 5 is moved. The tool post 5 is moved toward the work 14 while monitoring the load while the output torque of the tool 7 is limited, and the position of the tool post 5 when the load of the feed motor 7 exceeds the set level is read by the NC device. Calculating the number of roughing operations based on the deviation between the read value and a preset reference value,
Rough processing is performed based on the number of rough processing times calculated during work processing.

According to the fourth and fifth aspects of the present invention, the phase reference of the spindle is set. The fourth aspect sets the phase reference based on one measurement value. It is set on the basis of:

That is, according to the present invention, the turret 4
The workpiece detection member 12 is mounted on the lathe, the workpiece is loaded on the lathe, and the workpiece detection member 12 is advanced into the concave portion formed on the outer circumference or the inner circumference of the workpiece by the movement of the tool post 5, and the tool post 5 is stopped. With the output torque of the spindle indexing motor limited, the spindle 1 is rotated at low speed while monitoring the load,
The indexing position of the spindle at the time of machining the workpiece is set based on the phase of the spindle when the load of the spindle indexing motor exceeds the set level.

According to the fifth aspect of the present invention, the work detecting member 12 is mounted on the turret 4, the work is loaded on the lathe, and the work is detected in the concave portion formed on the outer or inner periphery of the work by moving the tool post 5. The member 12 is advanced, and the tool post 5
Is stopped, the spindle 1 is rotated at low speed while monitoring the load while the output torque of the spindle indexing motor is limited, and the phase of the spindle when the load of the spindle indexing motor exceeds the set level is set to the first reference. The phase is read by the NC device, and then the spindle indexing motor is rotated at a low speed in the reverse direction.
The NC device reads the phase at the time when the load exceeds the set level by rotating at a low speed after changing the advance position of the workpiece as the second reference phase, and based on the first reference phase and the second reference phase, the machining reference phase. Is calculated, and the indexing position of the spindle at the time of machining the workpiece is set with reference to the machining reference phase.

According to a sixth aspect of the present invention, the contact between the workpiece and the workpiece detecting member in each of the above methods is detected by a positional deviation of the servo control device, and the load of the motor is given to the servo control device of the motor. It monitors by monitoring a position deviation which is a difference signal between the position command and the position feedback signal, and a set level serving as a criterion for judging contact between the work and the work detection member is set by the position deviation amount. The work processing method according to any one of claims 1 to 5, wherein

[0014]

FIG. 1 is a block diagram showing an example of a motor load monitoring method according to a sixth aspect of the present invention. The spindle 1 of the lathe is supported by a headstock 2 which is substantially integral with a bed (not shown).
Is installed. The main shaft 1 has a through hole at the center so that the bar material can be supplied through the through hole.
The tool rest 5 equipped with the turret 4 is slidably mounted in a direction perpendicular to the main shaft (X-axis direction) on a slide base 6 slidable in the spindle direction (Z-axis direction). Z-axis direction feed motor 7 and X-axis direction feed motor 8 respectively
The feed screws 9 and 10, which are driven forward and reverse, are screwed together. The turret 4 is provided with a fixing jig (work detecting member) 12 made of a round bar machined to an accurate outer diameter at one location of the tool mounting station. The Z-axis and X-axis direction feed motors 7 and 8 are controlled by a servo controller 21.

According to the fourth and fifth aspects of the present invention, the spindle indexing motor (a dedicated indexing motor connected to the spindle via a built-in motor or an engagement / disengagement means) is provided by the servo controller 2.
1 is controlled. The servo controller 21 includes a difference detector 24, a compensation circuit 25, and a power amplifier 26. The difference detector 24 includes a position command a given from the NC device 22 and the pulse encoder 1 attached to the feed motor 7.
3 is supplied to the compensating circuit 25 with a difference signal (position deviation) c from the position feedback signal b given by the control circuit 3. Has given to.
The current output from the power amplifier 26 is limited by the set value of the maximum current setter 27. The NC device 22 increases or decreases this set value at a necessary timing. Although only the servo control system of the Z-axis direction feed motor 7 is shown in FIG. 1, the X-axis direction feed motor 8 and a spindle index motor (not shown) are similarly controlled by a similar control system.

The position deviation c output from the difference detector 24
Are detected by the position deviation detecting means 31. On the other hand, a set level d to be compared when detecting an increase or decrease in the position deviation.
Is set in the position deviation setting means 32, and the set values + d and -d on the plus side and the minus side are individually set. The comparator 33 outputs a control output e when the detected position deviation c reaches the set value d. The NC device 22 reads the coordinates of the tool post 5 when the control output e is output (when the control target is a spindle indexing motor, the phase of the spindle) and stores it in a memory.

The position deviation detecting means 31, the position deviation setting means 32 and the comparing means 33 are actually configured as a program of the NC unit 22. When the position deviation c cannot be obtained from the servo control device 21, the NC device 22
The position command a and the position feedback signal b of the pulse encoder 13 and the like are input to the position deviation detecting means 31, and the position deviation c is detected as a difference between them.

The above describes the method of monitoring the load of the motor using the position deviation and detecting that the load has exceeded the set level. The load of the motor is monitored by the current value flowing through the motor. Can also. However, the method using the position deviation described above enables more accurate load detection,
It is more suitable for implementing the present invention.

FIGS. 2 and 3 show an embodiment of the first aspect of the present invention. (A), (b), and (c) of FIGS. 2 and 4 show changes due to the progress of processing. The turret 4 of the lathe is loaded with the fixing jig 12 in advance. Work (Material) 14
Is loaded on the chuck 3 (S1), the turret 4 is rotated to index the fixing jig 12 toward the work 14 (S2), and the tip of the fixing jig 12 is moved closer to the measurement position (measurement start position) ( S3). This measurement position is
In consideration of the dimensional variation, the position is set outside the range of the dimensional variation and as close to the workpiece as possible. The turret 4 approaches the measurement position at high speed.

Next, the torque of the Z-axis feed motor is limited (S
4) In this state, the turret 4 is slowly moved in the Z-axis direction toward the work 14 while monitoring the load of the Z-axis feed motor 7 (S5). If the motor load exceeds the set level during this movement (S6), the Z-axis feed motor 7 is stopped (S6).
7) The Z-axis coordinates of the turret 4 are read (S8). Then, a shift value is calculated from the read coordinate values and a preset standard coordinate value, and the Z-axis coordinate system of the NC device is shifted (S9). Thereafter, the torque limitation of the Z-axis feed motor is released (S10), the turret 4 is rotated, and the tool 42 is indexed to the work 14 side to retract the fixing jig (S11), and processing of the work 14 is started (S11). S12).
In this processing, the position of the turret 4 is controlled to a position constantly shifted from the position described in the processing program or data.

FIGS. 4 and 5 show an embodiment of the third aspect of the present invention. The example shown in the figure is an example in which the processing shown in FIGS. 2 and 3 is performed on the first main spindle side of the two-spindle opposed lathe, and the work shown in FIGS. 4 and 5 is performed after the work 14 is moved to the second main spindle side. It is shown. Therefore, in FIG.
It is located on the right side.

The processing in FIG. 5 is the same as that in FIG. 3 from the loading of the workpiece (S1) to the step of reading the Z-axis coordinates of the tool rest 5 when the motor load exceeds the set level (S8). Next, the cutting allowance of the end face of the work is calculated from the read coordinate values (S13), and the number of rough machining of the end face is set with reference to a table or the like registered in the NC device in advance (S14). Thereafter, the torque limitation of the Z-axis feed motor is released (S10), a tool is indexed (S11), and machining of the work 14 is started (S12). With this control,
When the allowance is small, the number of times of rough machining can be reduced, and a decrease in machining efficiency due to useless movement of the blade can be avoided.

FIGS. 6 and 7 show an embodiment of the fourth aspect of the present invention. The work 14 in this embodiment is provided with an axial projection 14a on the outer periphery. In the flowchart of FIG. 7, the procedure from loading of the workpiece (S1) to bringing the turret 4 close to the measurement position at high speed (S3) is the same as that of FIG.

When the turret 4 reaches the measurement position, the tool post 5
Is stopped, and the torque (C-axis torque) of the spindle indexing motor for controlling the phase (C-axis) of the spindle is limited (S4).
The spindle is rotated at a low speed while monitoring the load of the spindle indexing motor (S5). If the motor load exceeds the set level during this rotation (S6), the spindle indexing motor is stopped (S7), and the phase of the spindle is read (S8). Then, a phase reference is set from the read coordinate values (S9). Thereafter, the torque limitation of the spindle indexing motor is released (S10), and the fixing jig is retracted by indexing the tool 42 (S11), and the work 14 is removed.
Is started (S12). When indexing the work 14, the work is indexed based on the set phase.

FIGS. 8, 9 and 10 show an embodiment of the fifth aspect of the present invention. 8A and 8B show a detection procedure, and FIG. 8C shows a phase measurement position. The work 14 of this embodiment has a D-cut 14b at the tip. In a series of flowcharts extending from FIG. 9 to FIG. 10, the coordinates of the tool rest 5 are read when the motor load exceeds a set level by applying a torque limit to the Z-axis feed motor 7 from the work loading (S1) (S8). The steps up to this are the same as in FIG.

Next, it is determined whether or not the phase of the work can be detected from the read Z-axis coordinates (S15). This determination is a detection of whether or not the tip of the fixing jig 12 has been inserted into the D cut 14b portion of the work from the Z-axis coordinates of the turret. If the phase cannot be detected, ie, the fixing jig 1
When the tip of No. 2 collides with the rightmost end face 14c of the work 14 and the load of the Z-axis motor increases, the phase of the main spindle 1 is changed or the X-axis coordinate position of the fixing jig 12 is changed. Attempt to insert the fixing jig into the D cut 14b again.

If the phase can be detected, the torque limitation of the Z-axis feed motor is released (S16), and the torque is applied to the spindle indexing motor (S17). Rotate at low speed in the plus direction (S
18). If the load of the motor increases during this rotation (S1
9) The spindle indexing motor is stopped (S20), and the phase of the spindle is read (S21). Then, from the read coordinate values, A
The phase of the point (see FIG. 8) is read (S22). Next, the spindle indexing motor is rotated at a low speed in the minus direction (S23),
As in the case of the plus rotation, when the motor load increases (S24), the spindle indexing motor is stopped (S25), and the phase at point B is read from the phase of the spindle (S26, S27).

The machining reference phase is calculated from the phases of the points A and B measured as described above (S28), and the machining reference is set in the memory of the NC device (S29). Thereafter, the torque limitation of the spindle indexing motor is released (S10), the fixing jig is retracted by indexing the tool 42 (S11), and the processing of the work 14 is started (S12). Work phase (C
When machining by determining the axis), for example, D-cut 14
When the milling process b is performed, the spindle is determined based on the processing reference phase set by the above method.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of a control system.

FIG. 2 is an explanatory view showing a processing method of the first embodiment.

FIG. 3 is a flowchart showing a processing procedure of the first embodiment.

FIG. 4 is an explanatory view showing a processing method according to a second embodiment.

FIG. 5 is a flowchart showing a processing procedure of the second embodiment.

FIG. 6 is an explanatory view showing a processing method according to a third embodiment.

FIG. 7 is a flowchart showing a processing procedure of a third embodiment.

FIG. 8 is an explanatory view showing a processing method according to a fourth embodiment.

FIG. 9 is a flowchart showing a processing procedure of the fourth embodiment.

FIG. 10 is a flowchart showing the processing procedure of the fourth embodiment (continuation of FIG. 9).

FIG. 11 is an explanatory view showing an example of a conventional method.

[Explanation of symbols]

 1 Spindle 4 Turret 5 Turret 7 Feed motor 12 Fixing jig 14 Work

Claims (6)

[Claims] 1. A state in which a work detecting member (12) is mounted on a turret (4), a work (14) is loaded on a lathe, and an output torque of a feed motor (7) moving a turret (5) is limited. While monitoring the load, move the tool post (5) toward the work (14), and read the position of the tool post (5) when the load of the feed motor (7) exceeds the set level with the NC device. Calculates the shift value based on the deviation between the read value and a preset reference value, and shifts the coordinate value of the work processing program by this shift value to control the position of the tool post (5) during work processing. A method of machining a workpiece on a lathe, characterized in that: 2. A state in which a work detecting member (12) is mounted on a turret (4), a work (14) is loaded on a lathe, and an output torque of a feed motor (7) moving a tool post (5) is limited. Move the tool post (5) toward the work (14) while monitoring the load, and use the position of the tool post (5) when the load of the feed motor (7) exceeds the set level as the first coordinate. Read with the NC device and then move the tool post (5) in reverse or move the tool post (5) by changing the position of the work detection member (12), and the load of the feed motor (7) will reach the set level. The position at the time of exceeding the position is read as the second coordinate by the NC device, a shift value is calculated based on the first coordinate and the second coordinate, and the coordinate value of the work processing program is shifted by the shift value to perform the work processing. A method for machining a workpiece on a lathe, characterized by controlling the position of a tool post (5) at the time of turning. 3. A work detection member (12) is mounted on a turret (4), and after a work (14) is loaded on a lathe, the output torque of a feed motor (7) moving a tool post (5) is limited. The turret (5) is moved toward the work (14) while monitoring the load in this state, and the position of the turret (5) when the load of the feed motor (7) exceeds the set level is set by the NC unit. Wherein the number of roughing operations is calculated based on a deviation between the read value and a preset reference value, and rough machining is performed based on the number of roughing operations calculated during work machining. Processing method. 4. A work detecting member (12) is mounted on a turret (4), a work is loaded on a lathe, and a work is detected in a concave portion formed on an outer or inner periphery of the work by moving a tool post (5). The member (12) is advanced, the tool post (5) is stopped, the spindle (1) is rotated at low speed while monitoring the load while the output torque of the spindle index motor is limited, and the load of the spindle index motor is reduced. Is based on the spindle phase when
A method of machining a workpiece on a lathe, comprising setting an indexing position of a spindle at the time of machining the workpiece. 5. A work detecting member (12) is mounted on a turret (4), a work is loaded on a lathe, and a work is detected in a concave portion formed on the outer or inner periphery of the work by moving a tool post (5). The member (12) is advanced, the tool post (5) is stopped, the spindle (1) is rotated at low speed while monitoring the load while the output torque of the spindle index motor is limited, and the load of the spindle index motor is reduced. Is read by the NC device as the first reference phase when the speed exceeds the set level, and then the spindle indexing motor is rotated at a low speed in the reverse direction or the advance position of the work detecting member (12) is changed to reduce the speed. The NC device reads a phase when the load exceeds a set level due to rotation as a second reference phase, calculates a processing reference phase based on the first reference phase and the second reference phase, and calculates a processing reference phase during work processing. Set the spindle indexing position based on the machining reference phase It characterized Rukoto, workpiece machining method in a lathe. 6. A motor load is monitored by monitoring a position deviation which is a difference signal between a position command given to a servo control device of the motor and a position feedback signal, and a set level is set by the position deviation amount. Characterized by
A work processing method for a lathe according to any one of claims 1 to 5.