JP3313001B2 - Control method at the start and end of machining of NC lathe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an NC lathe, and more particularly to a method for simultaneously controlling a plurality of spindles and a plurality of turrets by shifting a cycle start timing of a cycle machining which is simultaneously operated by a plurality of machining programs. NC to do
The present invention relates to a control method for starting and finishing a lathe.

[0002]

2. Description of the Related Art In an NC (numerical control) lathe, a spindle is rotated according to a machining program and its spindle center line direction (Z
Direction) and the movement of the tool rest in the X and Y directions (two directions orthogonal to each other in a plane orthogonal to the Z direction).
A machine tool that processes the material (work) held on the spindle with a tool (knife) attached to the tool post,
Recently, CNC lathes equipped with computers are becoming mainstream.

[0003] In such NC lathes, the processing speed has been increased, the processing efficiency has been improved, the processing accuracy has been improved, and the functions have been expanded (versatility), flexibility and safety have been improved. Measured and used in a wide range of component processing. The main spindle arrangement of such an NC lathe includes a single spindle having only one main spindle for face machining, two spindles having two spindles, and multiple spindles having many spindles. Some are equipped with a back spindle that is used for back processing.

Further, a plurality of spindles and a plurality of tool rests are provided, and a cycle start timing of cycle machining simultaneously operated by a plurality of machining programs is shifted so that a plurality of spindles share a tool rest or a back spindle side. There is also provided an NC lathe capable of increasing the processing efficiency by alternately performing the processing at the same time, and the present inventors have previously proposed the processing method. According to the conventional method, when performing such cycle control of the NC lathe, unnecessary synchronization commands and operations are performed before the entire system starts the cycle machining and after the cycle machining of a part of the system is completed. A special machining program with the command removed was added.

For example, in an NC lathe having a first spindle, a second spindle, and a back spindle, as shown in FIG. 14, a cycle (repetition) of simultaneously operating by machining programs A + B, B + A, and C + C of each spindle system.
When the processing is started with the start timing of each system shifted as shown on the left side of the figure, a dedicated first control for controlling one cycle at the start and removing unnecessary synchronization commands and operation commands is removed. A machining program of A '+ B' for the spindle system and a machining program of A "for the second spindle system are added. The portions indicated by broken lines in the second spindle system and the back spindle system in the figure are machining. Do not execute the program without executing the program.

When the machining of each spindle system is ended with a shift of the end timing as shown on the right side of FIG. 14, unnecessary synchronization commands and operation commands for controlling one cycle at the start are removed. B ″ machining program for the dedicated second spindle system and C ′ for the back spindle system
A machining program of + C ″ is added. The portions indicated by broken lines in the first spindle system and the second spindle system in the figure do not execute the machining program and do not perform machining.

[0007]

However, creating a dedicated machining program to be used only at the start and end of machining as described above not only requires extra labor and work cost, but also requires the machining program to be used. There is a problem that an extra storage capacity of a memory for storing is required.

The present invention has been made in view of such a problem, and uses a machining program for only a cycle machining portion as shown in FIG. It is possible to shift and start and end.

[0009]

In order to achieve the above object, the present invention shifts the cycle start timing of cycle machining, which has a plurality of spindles and a plurality of tool rests, and operates simultaneously by a plurality of machining programs. As a control method at the start of machining in an NC lathe that performs simultaneous machining, the same machining program as during cycle machining is executed from the beginning for a system that starts cycle machining with a delay, but actual machining is performed only during the delay period. It is characterized in that it is not allowed to do so. Therefore, it is preferable that the actual machining is not performed by machine-locking the spindle of the system that starts the cycle machining with a delay to a position where the machining material does not contact the tool.

[0010] As a control method at the end of machining, for a system in which cycle machining is terminated early, the same machining program as during cycle machining is performed until machining in a system in which cycle machining is terminated with a delay after machining is terminated. Is executed, but after the end of the processing, the actual processing is not performed. Therefore, it is preferable that the above-described actual machining is prevented from being performed by machine-locking the main spindle of the system that finishes the cycle machining early to a position where the machining material does not contact the tool.

[0011]

According to the control method at the start and end of machining of the NC lathe according to the present invention, the machining program for only the cycle machining portion as shown in FIG. Since the machining program is executed in all systems, it is possible to synchronize with each other, perform a cooperative operation, or perform an interference prevention operation. For the system that starts the cycle machining with a delay and the system that ends the cycle machining earlier, the actual period of the delay or the period until the machining of the system that ends the cycle machining the latest is completed. By not performing the operation, the start and end timings of the actual cycle machining can be arbitrarily shifted.

As a method for preventing actual machining during execution of the cycle machining program, it is easy to perform machine lock with the spindle of the corresponding system retracted to a position where the machining material does not contact the tool. However, as another method, the operation path can be changed using a small auxiliary program.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. FIG. 3 is an external perspective view showing an example of an NC lathe that implements the control method according to the present invention. This is an NC lathe of a headstock sliding type for machining a bar material, and has two spindles, one back spindle, and four tool rests. That is, as shown in FIG. 3, the first headstock 11A and the second headstock
A headstock (not shown) is slidably mounted along a guide rail (not shown) in a Z-axis direction (arrows Z1 and Z2 directions) parallel to the spindle centerline, and the first headstock 11A is provided.
The second headstock and the second headstock are independently moved in the directions indicated by arrows Z1 and Z2 by a Z1-axis servomotor (not shown) and a Z2-axis servomotor via a feed screw mechanism (not shown).

A first spindle which is rotatably supported by the first and second headstocks 11A and 11A and is independently rotated by a first spindle motor 12A and a second spindle motor (not shown), respectively. (Only the center line is indicated by A) and the second main axis (only the center line is indicated by B) are provided in parallel with each other at a predetermined interval.

In front of the first and second spindles, a tool rest base 13 is fixed to the bed 10 and stands upright over the entire width thereof. The tool rest base 13 has a first position at a position concentric with the respective center lines of the first and second spindles.
A guide bush 14A and a second guide bush 14B are provided, and the workpieces 15A and 15B gripped by the first and second spindles are slid in the Z-axis direction by the first and second guide bushes 14A and 14B. Guided movably.

The tool rest base 13 further has both sides (hereinafter, referred to as "reference straight lines") L intersecting the center lines A and B of the first main axis and the second main axis so as to be orthogonal to each other. The first tool rest 17A and the second tool rest 17B are disposed on the lower and upper sides, respectively. The first and second turrets 17
A and 17B are guide rails 16 formed on the front surface of the tool rest base 13 in parallel with the reference straight line L over the entire width thereof.
A, 16B, which are fitted to A, 16B and slide in a Y-axis direction (Y1, Y2 directions indicated by arrows) parallel to the reference straight line L.
A and 18B are mounted on X-axis tables 19A and 19B which slide in X-axis directions (X1 and X2 directions) orthogonal to both the Y-axis and the Z-axis.

The Y-axis table 18A is moved in the direction of arrow Y1 by a Y1-axis servomotor 20A attached to the tool rest base 13, and the Y-axis table 18B is moved to the Y2-axis servo motor 20B attached to the tool rest base 13.
Are driven along the guide rails 16A and 16B by the feed screw mechanism in the direction indicated by the arrow Y2, and can reciprocate over substantially the entire length thereof.

The X-axis table 19A is a Y-axis table 18A
The X-axis table 19B is moved in the X1 direction with respect to the Y-axis table 18A by the X1-axis servo motor 21A attached to the Y-axis table 18B by the X2-axis servo motor 21B attached to the Y-axis table 18B. In the direction, each is driven by a feed screw mechanism and is capable of reciprocating a predetermined stroke.

Each of the first and second tool rests 17A and 17B has a plurality (four in the illustrated example) of tools 22A,
, 22B,... Are attached in a comb-like shape at predetermined intervals in the Y-axis direction. In the illustrated example, the tool 22A,
, 22B,... Indicate the case where each of them is an outer diameter cutting tool such as a cutting tool.

Further, a rear tool post 23 is fixed to the tool post base 13 at an extension of the reference line L at the right end in FIG. 3, and a plurality of (three in the illustrated example) are provided on the rear tool post 23.
Are arranged such that their centers are arranged at predetermined intervals on the extension of the reference line L. This tool 24, ...
Is a tool for back processing, for example, a relative rotary tool such as a drill and an end mill. Even if the tools 24,... Do not necessarily rotate, they can be processed by rotating a work chucked to a back spindle described later.

On the front side of the tool rest base 13 of the bed 10, there is formed a groove 10a extending over the entire width in the Y-axis direction, and the upper surface of the step on the front side of the groove 10a is parallel to the reference line L. Forming a guide rail 25 extending in the direction
A rear headstock base 26 is slidably fitted to the guide rail 25, and a rear headstock 27 is slidable thereon in the arrow Z3 direction parallel to the center line of the rear main shaft provided therein. Is provided. The direction of the arrow Z3 is parallel to the directions of the arrows Z1 and Z2, which are the moving directions of the first and second headstocks described above.

The rear headstock base 26 is moved by a Y3-axis servomotor 28 attached to the bed 10 through a feed screw mechanism (not shown) in the arrow Y3 direction (the direction orthogonal to the arrow Z3 direction in the horizontal plane). Driven, bed 10
Can be reciprocated over substantially the entire width of. Rear headstock 27
Is driven by a Z3-axis servomotor 29 attached to the rear headstock base 26 via a feed screw mechanism (not shown), and is capable of reciprocating a predetermined stroke in the arrow Z3 direction with respect to the rear headstock base 26.

The rear spindle provided inside the rear headstock 27 has a center line at the height of the reference line L, a tip end provided with a chuck for gripping a work, and a spindle motor 30 for the rear spindle. Rotated by The work held on the back spindle is mainly the back tool post 2 described above.
3 are attached to the first tool post 17A or the second tool post 17B. If a tool for back processing is attached to the first tool post 17A or the second tool post 17B, it is also possible to carry out machining with them.

Further, an opposed turret 31 is fixedly provided on the left side surface of the rear headstock 27 in FIG. 3, and a plurality of (three in the illustrated example) tools 32,. At the same height, they are mounted so as to be arranged at predetermined intervals in the direction of arrow Y3. These tools 32,... Are also relatively rotating tools such as drills and end mills, and can perform drilling, thread cutting, and the like on the front end face of a rotating work held on the first or second spindle. It is.

The NC lathe can be machined by combining a first spindle and a second spindle (provided behind the tool rest base 13 and center lines A and B) with the first spindle and the second spindle, respectively. First turret 17A and second turret 1
7B and the opposed turret 31, the first main shaft and the second main shaft. The direction connecting the axes of the two main shafts (Y3 direction) and the direction approaching / separating from the two main shafts (arrows). A back spindle (provided in the back spindle head 27) that is relatively movable in the direction indicated by Z3) and a back tool post 23 that can be machined in combination with the back spindle.

A process for processing a workpiece (part) having a shape shown in FIG. 4 from a material of a round bar using this NC lathe will be described. In this case, the first and second tool rests 17A, 17
FIG. 5 shows an example of a tool layout of B, the back tool post 23 and the opposed tool post 31. The work W shown in FIG.
(Corresponding to the workpieces 15A and 15B shown in FIG. 1) are shaded, and each of the tools is 1-1.
2 (circled numbers in the figure) is attached.

Each tool name is as follows. 1: Center drill, 2: Drill, 3: Front turning tool,
4: Thread cutting tool, 5: Front turning tool, 6: Grooving tool, 7: End mill, 8: Back turning tool, 9: Cut off tool, 10: Back center drill, 11: Back drill, 12: Back tap

A round bar material is previously guided through the first and second spindles of the NC lathe shown in FIG. 3 and guided by the first guide bush 14A and the second guide bush 14B to slightly protrude. Then, the first spindle side having the first guide bush 14A and the second guide bush 14B perform the simultaneous machining by shifting the machining process by a half cycle.

The machining process will be described for the work on the first spindle side. First, the opposed tool rest 31 is attached to the center of the front end surface of a round bar (work W) chucked by the first spindle and protruding from the first guide bush 14A. The back spindle 27 is moved so that the center drill 1 faces the first spindle spindle motor 12A, and the first spindle is rotated by the first spindle spindle motor 12A.
While rotating the first headstock 11A or the back headstock 2
7 is moved in the Z-axis direction to make a center hole in the front end face of the work W. Next, the same operation as described above is performed using the drill 2 of the opposed tool post 31, and a hole having a predetermined inner diameter and a predetermined depth is formed in the front end of the work W.

After that, the first tool rest 17A is moved so that the front cutting tool 3 is positioned on the center line A of the first spindle.
The workpiece W is lowered in the direction indicated by the arrow X1 to process the outer periphery of the thread portion of the work W into a predetermined diameter and length. And the first tool post 17A
Thread the outer periphery using a threaded cutting tool 4.

Next, after the large diameter portion of the work W is machined to a predetermined diameter using the front cutting tool 5 (same as 3) of the first tool post 17A, the first tool post 17A is moved toward the second spindle. , Second
The tool post 17B is moved to the first spindle side to switch the combination of the spindle and the tool post. Then, a groove having a predetermined depth is cut at the rear portion of the large-diameter portion of the work W using the grooving bit 6 of the second tool post 17B, and then the work W is fixed and the end mill 7 is used. Is reciprocated in the direction of the arrow X1 to form a plane portion parallel to a position facing the outer periphery of the large diameter portion behind the groove of the work W. Then, the work W is rotated again, and the rear small diameter portion is machined into a predetermined diameter by using the rear cutting tool 8 of the second tool rest 17B.

Thereafter, the rear spindle head 27 is moved in the direction of arrow Z3 to hold and hold the front end of the workpiece W with the chuck of the rear spindle, and the second tool post 1 is cut off using the cutting tool 9.
7B is reciprocated in the direction of arrow X1 to perform cut-off processing, and the work W is cut off from the round bar. This delivery of the work W is called pick-off.

Then, the rear headstock 27 is moved to the rear tool post 23.
Then, the back spindle is rotated and the back spindle is rotated, and a center hole is made in the back (rear end face) of the work W using the back center drill 10. Further, a hole having a predetermined inner diameter and a predetermined depth is formed by using the back drill 11, and a tap is cut on the inner periphery thereof by using the back tap 12, thereby completing the entire machining process for the work W.

The machining of the same work as that of the first spindle is performed in the second
Also on the main spindle side, it starts with a half cycle delay, and the processing on the back main spindle side starts after all the first processes on the first main spindle side are completed. Thereafter, each time the work is completed on the first spindle side and the second spindle side, the work is received on the back spindle side and the back processing is performed alternately within a half cycle of all the processes on the spindle side.

FIG. 7 shows the relationship between the use order of the above-described tools on each axis side and the time required for each machining step in the second and subsequent cycles according to this embodiment. In this figure,
Indicates the machining on the first spindle side, # 2 indicates the machining on the second spindle side, and # 3 indicates machining on the back spindle side. The circled numbers indicate the signs of the tools to be used in the same manner as in FIGS. "Is a step of gripping and receiving the workpiece cut off on the first spindle side or the second spindle side on the rear spindle side. The vertical axis is time (seconds), and the length of each hatched frame in the vertical direction is proportional to the processing time by each tool (indicated by a circled number in the frame).

As described above, in this embodiment, the time required for the back spindle side machining step (including the pick-off step) is less than half the time required for the first and second spindle side machining steps. Efficiency is closer to half because the waiting time is reduced. If it exceeds half, a waiting time will occur on the spindle side, but if it is slightly longer, there is no practical problem. In order to shift the machining steps on the first spindle side and the second spindle side by a half cycle, if all the steps are divided so that the former half and the latter half are exactly 1/2 (1: 1) as in this embodiment. It is ideal, but if it is divided into about half, there will be no problem even if there is a slight difference, with only a little waiting time.

FIG. 6 shows an example of another tool layout for processing the work shown in FIG. Back turret 2
3 includes back surface processing tools 10 to 12 as in the example of FIG.
Are attached but are not shown. In this example, the opposed tool post 31 is not used, and all the tools 1 to 9 necessary for machining on the first and second spindle sides are attached to the first tool post 17A and the second tool post 17B, respectively. The center drill 1 and the drill 2 are attached via a tool holder 33 in a direction orthogonal to the plane of the drawing and facing the front end surface of the workpiece W. Therefore, according to this tool layout,
Since there is no need to replace the first tool rest 17A and the second tool rest 17B during the machining process on the first spindle side and the second spindle side, the machining time can be shortened accordingly.

Next, the configuration of the control unit of the NC lathe shown in FIG. 3 will be described with reference to the block diagram of FIG. The control unit includes a system control unit 40 including a CPU, a program input unit 41, a keyboard 42a, and a switch 42.
b, an operation panel 44 having a display 43, an input / output control unit 45 thereof, and a system control program memory (RO).
M) 46, an automatic programming unit 47, a machining program memory 48, a display data storage unit 49, a RAM 50 for storing other data, a machining program processing unit 51, a communication control unit 52, and a machining operation control unit 53, A drive unit 60 that directly drives and controls the mechanism unit shown in FIG. 3 via the operation control unit 53 is controlled. For example, rotation / stop of each spindle, rotation number instruction, chuck opening / closing, tool correction of the tool post, and the like are performed.

The drive section 60 is provided with a servomotor (20A, 20B, 21A, 21B, 28, 29) for each axis shown in FIG.
Etc.), a control drive unit 62 for each axis for driving and controlling a servo mechanism 61 for each axis motor, and a spindle motor (12
A, 30 etc.) 63 includes a spindle motor control drive section 64 for controlling the drive, a sensor input section 66 for inputting a detection signal of each sensor (rotational speed sensor of each spindle motor, position sensor of each table, etc.) 65 and the like. .

The system control unit 40 controls the entire control unit, that is, the entire NC lathe. The system control unit 40 creates a machining program together with the automatic programming unit 47. The system control unit 40 determines the system of the machining program created together with the machining program processing unit 51. Processing such as conversion, division, editing, etc., input of data and commands from the keyboard 42 a or switch 42 b of the operation panel 44 via the input / output control unit 45, processing related to processing programs and other displays on the display 43, processing operation control unit Machining program memory 4 with 53
8 based on the machining program stored in
For example, a process for performing NC processing by operating 0 is performed.

The program input unit 41 is a paper tape reader, a floppy disk device (FDD), or the like for inputting a processing program created by an external program creating device (a personal computer or the like) from a paper tape or a floppy disk. The operation panel 44 issues an operation command from the keyboard 42a or the switch 42b when performing the NC processing.
A driving operation means for confirming the operation based on the display on the display 43. The automatic programming unit 47
When the machining program necessary for the NC lathe itself is created by using the function (1), it becomes an interactive input means for performing interactive automatic programming.

The input / output control unit 45 determines commands and inputs from the keyboard 42 a or the switch 42 b of the operation panel 44, and controls the display of the display data stored in the display data storage unit 49 on the display 43. Do. The system control program memory 46 is a ROM that stores programs and fixed data used by the CPU of the system control unit 40 to control the operation of the control unit.

The automatic programming unit 47 includes an operation panel 44
And a function unit for creating a machining program, and is actually a function of the system control unit 40, but is shown as another block for easy understanding. The machining program memory 48 includes a machining program storage unit 4 for storing a part program and a process subprogram described below.
8a, a process editing program storage unit 48b for storing a process editing program created by the automatic programming unit 47 for each system, and a backup program storage unit 48 for storing a backup program used when a trouble occurs.
c and the like.

The display data storage section 49 is a memory (RAM) for storing various data to be displayed on the display 43 of the operation panel 44, and also stores process subprogram display data and process edit program display data corresponding to each axis system. It is stored here. The RAM 50 is a memory that stores data of each tool (tool) used for machining, various initial set data, and the like. If the storage capacity of the RAM 50 is sufficient, the machining program memory 48 and the display data storage unit 49 can also be used.

The machining program processing section 51 is a functional section for performing processing such as system identification, conversion, division, and editing of the created machining program.
This is a function that 0 has. The communication control unit 52 is a circuit that controls communication with an external system such as a DNC device. The communication control unit 52 transfers the created machining program to the external system and stores the created machining program in the storage medium, or fetches the machining program from the external system. Used when

Here, a method of creating a machining program according to this embodiment will be described. Creating a machining program
As described above, it is created by the system control unit 40, the automatic programming unit 47, and the operation panel 44 of the control unit shown in FIG. The creation procedure at that time is shown in the flowchart of FIG. FIG. 10 shows an example of the created part program and its process subprogram, and FIG. 11 shows an example of the process editing program.

According to the flowchart of FIG.
First, a part program which is a normal program of NC machining is created.
It is stored in the machining program storage section 48a of the machining program memory 48 shown in FIG. This part program is created by an external device, fetched from the program input unit 41 or the communication control unit 52, and stored in the machining program storage unit 4
8a.

This part program is, for example, shown in FIG.
As shown in (A), a program of each process required for processing one target part is converted into a work order using an indirect command that does not specify a spindle or a tool post used for a command relating to the spindle and the tool post. This is a series of programs described.
Here, a code consisting of N and a four-digit number such as N0010 and N0020 is a program number for each process. G00,
A code with a number after G, such as G50, indicates the instruction content of the preparation function (G function), G00 is fast-forward, G50
Indicates an offset position.

Codes with a number after M, such as M03 and M06, indicate the instruction contents of an auxiliary function (G function), ie, a function for actually performing some operation such as turning on / off a motor other than a servomotor. M03 commands clockwise rotation of the spindle, and M06 commands tool change. S5
A code consisting of S and a four-digit number, such as 200, is a code for an S function for selecting the rotation speed of the spindle, and S5200 is a command for setting the rotation speed of the spindle to 5200 rpm.

Numerical values with decimal points after X, Y, and Z are as follows:
The moving distance in each of X, Y, and Z directions is shown, and the sign of the numerical value indicates the moving direction. The value after F commands the feed rate. A code consisting of T and a numeral following it indicates a tool selection command. This part program is compiled as a process subprogram for each machining process (for each program number such as N0010 and N0020) as shown in FIG. 10B.

Then, the processing time for each process subprogram is calculated. The machining time can be calculated based on the feed speed and the feed distance of the work or tool described in the process subprogram and the initial data stored in advance, but before calculating the machining time for each process subprogram. , The first tool post 17A and the second tool post 17B
By performing a tool layout that determines the type of tool to be mounted on the tool, it is possible to calculate the machining time in consideration of the time required for actual tool change.

The calculated machining time for each process subprogram and the accumulated machining time can also be displayed on the display 43 of the operation panel 44. Thereafter, it is determined whether or not the machining time of the entire process subprogram is divided into about 2: 1 on the main spindle side and the back spindle side. This may be automatically determined by the system control unit 40, or the operator may input a result determined by looking at the accumulated machining time displayed on the display 43.

If the processing can be divided, all the process sub-programs are processed with a machining time of about 2: 1 between the spindle side and the back spindle side.
Then, a process editing program is created by dividing into a main spindle system and a rear main spindle system. Further, it is determined whether or not the process editing program of the spindle system can be divided into process subprogram units at approximately half of the total machining time. This determination is also made automatically or by interactive input as in the above-described determination.

If it can be divided, the process editing program of the main spindle system is divided into the first half and the second half so that the machining time is approximately 1: 1. Is created and stored in the process editing program storage unit 48b of the machining program memory 48 as a machining program on each axis side.

FIG. 11 shows an example of the result of the creation of the process editing program. Here, the spindle systems 1, 2, and 3 are a first spindle system, a second spindle system, and a rear spindle system, respectively. The broken lines of each system indicate the first and second half divided lines. In the main spindle system 1 and the main spindle system 2, the first and second half process subprograms are switched. In the spindle system 3 (back spindle system), the first half and the second half are configured by the same process subprogram. This process editing program is stored for each system in the process editing program storage section 48a of the machining program memory 48 shown in FIG.

In this example, each process subprogram constituting the process editing program has a program number (N001).
0, N0020, etc.), the program number and the tool code (T1200, T1300) used in the process.
Etc.) are stored in pairs. M02 is a command indicating the end of the machining program. This process editing program can be displayed on the display 43 for confirmation.

In this way, a program system is provided for each of the first main spindle, the second main spindle, and the rear main spindle, and the program sub-system of the first main spindle includes the above-described process subprograms of the main spindle side process in the first half and second half. In the second spindle program system, the process sub-programs of the spindle-side process are arranged in the latter half and the first half in order, and in the rear spindle-side program system, the process sub-programs of the back spindle process are arranged in the order of the processes. I do.

Further, in the embodiment shown in FIG. 9, the process subprogram of the spindle side process is not divided in units of process subprogram so that the machining time of the spindle side and the back side is 2: 1, and If the process editing program cannot be divided by about half of the machining time, the process subprogram is re-edited, and the process subprogram that extends before and after the place to be divided is divided into two to form separate process subprograms. The process after the calculation of the machining time in the unit of the process subprogram is executed to create the process editing program.

In this manner, the process subprograms which are close to ideal can be distributed to each system, and the processing efficiency can be maximized. The process editing program of FIG. 11 is a parent program,
The part program or the process subprogram in FIG. 10 can be viewed as a child program. As a result, it is possible to disassemble the two thoughts of the details of the tool path and the entire method of arranging the processes, and to arrange the operations.

Basically, a child program is considered as a single-system program whose operation is determined by X and Z on a plane, and a parent program is considered as a program in which the order of processes and the queuing relationship between processes are developed in multiple systems. At the time of editing or execution, if you look at only the parent program, you can understand the whole situation, but it is difficult to understand individual operations. Therefore, in the state where the parent program is displayed, the child program (process subprogram) can be displayed in a window by designating the program number (N0010, N0020, etc.) as necessary.

FIG. 12 shows a display example of a machining program having a single-layer structure for each spindle system according to the present embodiment. Part programs (child programs) are displayed in a table format for each spindle system, and are scrolled up and down. The whole of each child program can be displayed. Thereby, it is possible to confirm the details of the part program of each spindle system.

FIG. 13 shows an example in which the accumulated machining time when the machining program of each spindle system shown in FIG. 12 is executed is displayed in a graph showing the ratio of the machining time by each process subprogram (N ****). FIG. The length in the vertical direction of the hatched area in which the number of each process subprogram is displayed is proportional to the processing time of the process.

In the spindle system 1, the process subprogram N00
10 to N0030 are the first half, and N0040 to N0070 are the second half. In the spindle system 2, only the first half and the second half are interchanged. The machining time of all the process subprograms of the spindle system 3 (the back spindle system) is slightly shorter than half of the machining time of all the process subprograms of the spindle systems 1 and 2, and the machining time of each of the spindle systems 1 and 2 is one time. It can be seen that the same processing is performed twice during the processing.

Here, a control method at the start and end of cycle machining according to the present invention will be described in detail. First, as for the operation at the time of new start, a case where the combination of the spindle and the tool post is fixed and a case where the combination is replaced will be described.

FIG. 16 is a side view of the relationship between the workpiece and the cutting tool at the time of new start when the combination of the spindle and the tool post is fixed, as viewed from the front and side of the first spindle and the second spindle. Is shown. FIG. 17 is an explanatory diagram of a new start step when the cycle machining start timings of the first spindle side and the second spindle side are shifted by サ イ ク ル cycle.

(A), (B) and (C) in FIG. 16 correspond to the timings A, B and C in FIG. In this case, cut-off tools 91 and 92 are mounted on the first and second tool rests, respectively, and are prepared for the first main spindle and the second main spindle, respectively. In FIG. 16A, both axes are set to the start state, and the cut-off tools 91 and 92 are set to the workpieces W1 and W.
2 is suppressed. When the start is performed at the timing A in FIG. 17, the parting-off processing of the workpiece W1 by the parting-off tool 91 of the first tool post is immediately started on the first spindle side.
The second spindle side remains in the starting state.

When the machining on the first spindle side progresses to about half as shown in FIG. 16B, machining by the cut-off tool 92 of the second tool post on the second spindle side is started at timing B in FIG. You. Then, the machining on the second spindle side is performed as shown in FIG.
As shown in (1), the machining on the first spindle side is completed at timing C in FIG. 17 and returns to the same state as at the start of (A), and the second machining operation is started. The machining on the second spindle side continues for another half cycle. When the cycle machining program is also executed on the second spindle side between the timings A and B, the material (work W2) on the second spindle side is retracted and the second spindle is machine-locked, thereby realizing the actual operation. No processing can be performed.

When the machining on the first spindle advances to about half as shown in FIG. 16B, the machining by the cut-off tool 92 of the second turret on the second spindle is started at timing B in FIG. You. Then, the machining on the second spindle side is performed as shown in FIG.
As shown in (1), the machining on the first spindle side is completed at timing C in FIG. 17 and returns to the same state as at the start of (A), and the second machining operation is started. The machining on the second spindle side continues for another half cycle.

FIG. 18 is a view similar to FIG. 16 at the time of a new start when the combination of the spindle and the tool post is replaced, and FIG. 19 is an explanatory view of a new start step similar to FIG. 17 in that case. In this case, the cut-off tool is mounted on only one of the tool rests (for example, in the first case, the cut-off tool 91 is mounted only on the tool rest), and the tool rest is located between the two headstocks. Between the timings A and B after the start-up,
A byte is used on the spindle side as well as when the cycle machining program is executed and continuation is started.

However, the material (work W2) on the second spindle side
As shown in FIG. 18A, the machine is locked in a state in which it is retracted to a position where it does not come into contact with the parting tool 91, which is a tool, so that actual machining is not performed. Alternatively, there is a method in which the operation paths of the tool rest and the headstock are changed so that actual machining is escaped so as not to reach actual cutting.

When the machining on the first spindle side progresses to about half as shown in FIG. 18B, the cut-off tool 91 is selected on the second spindle side at the timing B in FIG. 19, and the machine lock is released at that stage. The material W is released and the processing is started. At timing C in FIG. 19, as shown in FIG. 18C, the machining start state is reached again on the first spindle side, and the second spindle side passes through half of the machining as in the case of starting continuation.

The above example is an example in the case of performing machining with two spindles. FIG. 20 is an explanatory diagram of various start processes in the case of performing cycle machining in which start timing is shifted using two spindles and a back spindle. FIG. 21 is an explanatory diagram of the different end steps. 20A shows a new start step when the combination of the spindle and the tool rest is fixed, FIG. 20B shows a new start step when the combination of the spindle and the tool rest is replaced, and FIG. Each step will be described.
The continuation start step when the combination of the main shaft and the tool post is fixed is the same as the process (C) except that the tool post is not replaced at the half cycle. FIG. 21A shows an end step of the first spindle system when an odd number of workpieces are machined.
(B) shows an end step of the second spindle system when an even number of workpieces are machined.

FIG. 22 shows an example of a machining program for implementing the above-described control method at the start and end of machining according to the present invention. This machining program is a process editing program for each spindle system similarly to that shown in FIG. 12, and M2 is a command indicating the end of the program. M10 before the end of the spindle system 1 program.
1. Special codes of G101 are inserted at the beginning of the program of the spindle system 2, G102 and M102 in the middle, and special codes of M101 and M102 at the middle and before the end of the program of the spindle system 3 (back spindle system). FIG. 2 shows this clearly.
It looks like 3.

In FIG. 22, if the program enclosed by G101 and G102 is [A], actual processing is not performed in [A] at the time of new start. At the start of continuation, actual processing is performed in this [A]. When there is an end command for the spindle system 1, the spindle system 1 ends at M101, and thereafter, no machining is performed. In the spindle system 3, the back side machining of the work machined by the spindle system 1 is performed, and the program M
The processing ends at 101, and no further processing is performed thereafter. Unless there is a second spindle end command, the second spindle system continues machining.

When there is an end command for the spindle system 2, the spindle system 2 is terminated at M102, and thereafter, no machining is performed. In the spindle system 3, the back surface machining of the work machined by the spindle system 2 is performed, and the process is completed in M102 of the program.
Do not process after that. Unless there is a command to end the first spindle, the first spindle system continues machining.

FIG. 1 is a flow chart showing an example of control processing at the start of machining in an NC lathe according to an embodiment of the present invention, and FIG. 2 is a flowchart showing an example of control processing at the end of machining. In the control process at the start of machining in FIG. As a result, if it is not a new start, continuous operation is performed. If it is a new start, the spindle systems 1 and 3 execute the respective programs shown in FIG. 22 from the top. In the main spindle system 2, G101 and G102 are enabled, and when G101 is detected, the chuck is closed and the Z axis is set to Lm.
Then, the Z-axis is machine-locked by retracting the material m so that the material does not contact the tool.

Thereafter, when G102 is detected, the machine lock is released, the Z-axis is advanced by L mm, and then G101, G1
02 is invalidated and the operation proceeds to continuous operation. Thereby, the new start shown in FIG. 20A or 20B can be performed.

In the control processing at the end of machining in FIG. 2, it is determined whether the end signal is the spindle system 1 (# 1) or the spindle system 2 (# 2). In the case of odd-numbered machining, the spindle system 1 is used. In this case, the last one is machined by the spindle system 1. At the same time, in the spindle systems 2 and 3, when M102 is detected in # 2, the chuck of the second spindle is closed, the Z axis is retracted by L mm, and the machine is locked. Thereafter, when M101 is detected in # 3,
And terminates the processing. Thus, the end of the first spindle system shown in FIG. 21A can be performed.

In the case of machining of an even number, the end signal is the spindle system 2 (# 2), and in this case, the last one is machined by the spindle system 2. At the same time, in the spindle systems 1 and 3, M10
1 is detected, the chuck of the first spindle is closed, and the Z axis is moved to Lm.
Move backward and lock the machine. Then, M3 at $ 3
When detecting 2, the program end (M2) of # 3 is detected and the process is terminated. Thus, the end of the second spindle system shown in FIG. 21B can be performed.

[0080]

As described above, according to the present invention, the N
According to the control method at the start and end of machining of the C lathe, the cycle machining operation of a plurality of systems cooperating with each other of the NC lathe can be started and ended at a shifted timing by the machining program of only the cycle machining portion. .
Therefore, it is not necessary to create four special programs to be used only at the start and end of the machining, and the creation of the machining program is facilitated, and the operation cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of a control process at the time of starting machining according to the present invention in an NC lathe.

FIG. 2 is a flowchart showing an example of a control process at the end of machining according to the present invention in an NC lathe.

FIG. 3 is an external perspective view showing an example of an NC lathe that implements the control method according to the present invention.

FIG. 4 is an explanatory diagram of an example of a work (part) to be machined using the NC lathe shown in FIG. 3 and a machining process thereof.

5 is a diagram showing an example of a tool layout for each tool post for performing the machining shown in FIG. 4;

FIG. 6 is a diagram showing an example of a tool layout when the machining shown in FIG. 4 is performed using only the first and second turrets.

FIG. 7 is a diagram showing a relationship between machining times by each tool on each axis side when the machining shown in FIG. 4 is performed by the machining method of the present invention.

FIG. 8 is a block diagram showing a configuration of a control unit of the NC lathe shown in FIG.

FIG. 9 is a flowchart showing a machining program creation procedure by the control unit of FIG. 8;

FIG. 10 is a diagram showing an example of a part program created by this embodiment and its process subprogram.

FIG. 11 is a diagram showing an example of a process editing program created by this embodiment.

FIG. 12 is a diagram showing a display example of a machining program having a single-layer structure for each spindle system according to the embodiment.

13 is a diagram showing an example in which the accumulated machining time when the machining program of each spindle system of FIG. 12 is executed is displayed in a graph showing the ratio of the machining time by each process subprogram.

FIG. 14 is an illustration showing an example of a machining program according to the prior art in which simultaneous machining is performed by shifting the start timings of cycle machining that are simultaneously operated by a plurality of machining programs in an NC lathe.

FIG. 15 is an explanatory diagram showing an example of a machining program when the present invention is applied.

FIG. 16 is a diagram showing the relationship between the workpieces on the first and second spindles and the cut-off tool at the time of a new start when the combination of the spindle and the tool rest is fixed.

FIG. 17 is an explanatory diagram of a new start step when the cycle machining start timings of the first spindle side and the second spindle side are shifted by サ イ ク ル cycle.

FIG. 18 is a view similar to FIG. 16 at the time of a new start when the combination of the spindle and the tool rest is exchanged.

FIG. 19 is an explanatory diagram of a new start step similar to FIG. 17 in that case.

FIG. 20 is an explanatory diagram of various start steps when performing cycle machining with start timings shifted using two spindles and a back spindle.

FIG. 21 is an explanatory view of the different end step.

FIG. 22 is a diagram showing an example of a machining program for executing the control method at the start and end of machining according to the present invention.

FIG. 23 is a view showing the insertion position of the special code for easy understanding.

[Explanation of symbols]

W: Work (part to be processed) 10: Bed 1
0a: Groove 11A: First spindle head 12A: Spindle motor for first spindle 13: Tool post base 14A: First guide bush 14B: Second guide bush 15A, 15B: Work 16A, 16B, 25: Guide rail 17A: First 1
Tool post 17B: 2nd tool post 18A, 18B: Y axis table 19A, 19B: X axis table 20A: Y1 axis servo motor 20B: Y2 axis servo motor 21A: X1 axis servo motor 21B: X2 axis servo motor 22A, 22B, 2
4, 32: Tool 23: Back tool post 26: Rear headstock base 2
7: Back spindle head 28: Servo motor for Y3 axis 29: Servo motor for Z3 axis 30: Spindle motor for rear spindle 31: Opposite turret 33: Tool holder 40: System control unit 41:
Program input unit 42a: Keyboard 42b: Switch 43: Display 44: Operation panel 45: Input / output control unit 46: System control program memory (ROM) 47: Automatic programming unit 48: Processing program memory 49: Display data storage unit 50: RAM 51: machining program processing unit 52: communication control unit 53: machining operation control unit 60: drive unit 61: servo mechanism for each axis motor 62: control drive unit for each axis 63: spindle motor for each spindle 64: spindle motor control Driving unit 65: Each sensor 66: Sensor input unit

Continued on the front page (72) Inventor Yuji Miyazaki 840 Citizen Watch Co., Ltd., Tokorozawa City, Saitama Prefecture (72) Inventor Kimio Hamada 840 Citizen Watch Co., Ltd. 72) Inventor Tatsuaki Wada 840 Citizen Watch Co., Ltd., Tokorozawa Office, Tokorozawa-shi, Saitama (56) References JP-A-1-250106 (JP, A) JP-A-1-281801 (JP, A) (58) ) Field surveyed (Int.Cl. ⁷ , DB name) B23Q 15/00-15/28 G05B 19/18-19/46 B23Q 37/00-41/08 B23B 3/30

Claims (4)

(57) [Claims] 1. An NC lathe having a plurality of spindles and a plurality of turrets, wherein the simultaneous machining is performed by shifting the cycle start timing of the cycle machining simultaneously operated by a plurality of machining programs. A method for starting machining of an NC lathe, characterized in that the same machining program as that during cycle machining is executed from the beginning, but actual machining is not performed only during the delay period. . 2. The method according to claim 1, wherein the main shaft of a system for starting the cycle machining with a delay is retracted to a position where the machining material is not brought into contact with the tool. A control method at the time of starting machining of the NC lathe, wherein the actual machining is not performed. 3. An NC lathe having a plurality of spindles and a plurality of turrets and simultaneously performing the machining by shifting a cycle start timing of the cycle machining simultaneously operated by a plurality of machining programs. For the system to be ended, the same machining program as during the cycle machining is executed until the machining of the system that ends the cycle machining with a delay even after the end of machining, but the actual machining is not performed after the machining is completed. A control method at the time of finishing machining of an NC lathe, characterized in that: 4. The control method at the end of machining of an NC lathe according to claim 3, wherein the machine is locked in a state where the main spindle of a system for ending the cycle machining early is retracted to a position where the machining material is not brought into contact with the tool. And a method for controlling when the machining of the NC lathe is completed, wherein the actual machining is not performed.