JP2011237880A - Controller of machine tool equipped with tool change position automatic determination function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller of machine tool capable of reducing time for tool change operations.SOLUTION: The controller calculates a maximum ejection amount TmaxLx in a direction of tool axis and a maximum ejection amount LmaxLz in a direction perpendicular to the tool axis of a tool currently used, a tool to be used next and a tool disposed between the tools on a turret; causes the tools to move in a direction of an instructed tool change position Pa; and determines whether a condition A (condition A:Xr>Xi+TmaxLx) or a condition B (condition B:Zr>Zi+TmaxLz) is satisfied. If either/both condition is satisfied, the tools are changed after being moved axially. Otherwise, the controller returns to a step SA101 to determine if a work and the tools interfere with each other or not when the tools move from an auto-determined tool change position Pb to a next start position Pc. If interference will occur, a bypass point Pi for avoiding the interference is calculated and inserted before the start position Pc to complete a movement command for the tools.

Description

  The present invention relates to a machine tool control device having a function for automatically determining a tool change position.

  A conventional tool change operation will be described with reference to FIGS. FIG. 13 is a diagram illustrating a tool post on which a plurality of types of tools are mounted. FIG. 14 is a diagram for explaining a conventional tool change operation.

  Conventionally, in the tool exchange operation, after the machining cycle A using the tool T1 is completed, the tool is moved to the tool exchange position Pa commanded by the program from the end position P in order to exchange the tool T3 used in the next machining cycle B. . After reaching the tool change position Pa, the tool post rotates and the tool T3 used in the machining cycle B is changed. After the tool change is completed, it is executed in the machining cycle B and moved to the start position Pc.

  In Patent Document 1, when creating a machining program that is executed by a numerical controller and performs machining of a workpiece, a machining cycle is created by paying attention to machining contents in order to shorten the machining program creation time. A method is disclosed in which a plurality of processes are combined to form a machining program. Further, Patent Document 2 discloses a method of inserting a manual interruption into a program as a tool change operation during a machining cycle.

JP-A-55-58946 JP 58-172708 A

  However, the method of combining machining cycles disclosed in Patent Document 1 tends to require a longer machining time than the method of sequentially programming tool operation commands, and in particular, attempts to machine a large number of workpieces. It will be disadvantageous if you do. In the method disclosed in Patent Document 2 that solves the problem of long processing time, if the tool is changed due to various reasons such as wear or breakage of the tool, it is necessary to manually teach again, which is troublesome. There is a problem that it takes.

  Accordingly, an object of the present invention is to solve the problem of shortening the time required for the tool change operation and increasing the machining time in a numerical control apparatus that executes a machining program in which a plurality of machining cycles are combined with the tool change operation interposed therebetween. It is an object of the present invention to provide a control device for a machine tool.

The invention according to claim 1 of the present application has a tool post or a spindle head having a turret that can be rotated by mounting a plurality of tools, and is preset in a tool change position commanded by a machining program or in a machine. In a control device of a machine tool provided with a tool changer that rotates the turret at a tool change position and indexes the tool to a predetermined position, the tool is an area where the tool interferes with other structures and cannot be changed. An area setting means for setting a tool change impossible area;
From a reference position of the tool post or spindle head to a protrusion amount acquisition means for obtaining a protrusion amount that is a distance from the tool tip or spindle head to the tip of each tool, and from the end position of the machining step before tool replacement In the path of moving to the tool change position, the tool is changed when the tool is changed based on the currently used tool, the next tool to be used, the maximum protrusion amount of the tool between them, and the tool change impossible region. Means for determining, as a new tool change position, a position that does not interfere with the tool non-changeable region, and when a tool change command is issued by the machining program, the machining end position of the machining step before the tool change is The turret is moved to the new tool change position obtained by means, and the turret is rotated to divide the tool into a predetermined position. A control device for a machine tool, characterized in that by changing the tools.

The invention according to claim 2 is an interference avoidance path for obtaining an interference avoidance path in which the tool and the workpiece do not interfere with each other in the path moving from the new tool change position to the start position of the next machining step programmed by the machining program. 2. The machine tool control device according to claim 1, further comprising an acquisition unit, which moves to a start position of a next machining step through an interference avoidance path obtained by the interference avoidance path acquisition unit.
The invention which concerns on Claim 3 has the update means which updates the said machining program as a movement command to the new tool exchange position and the said interference avoidance path | route to a tool exchange position and the starting position of the next machining process, The machine tool control device according to claim 1.

  According to the present invention, in a numerical control apparatus that executes a machining program in which a plurality of machining cycles are combined with a tool change operation interposed therebetween, a machine that can shorten the time required for the tool change operation and solve the problem of increasing the machining time. A machine control device can be provided.

It is a figure explaining the tool post which mounts multiple types of tools. It is a figure explaining the tool exchange operation concerning the present invention. It is a figure explaining the tool post which mounts multiple types of tools. It is a figure explaining the coordinate position of the tool change position Pb determined automatically. It is a figure explaining the tool change position Pb determined automatically when escape amount (X) is small and escape amount (Z) is large. It is a figure explaining the tool change position Pb determined automatically when the escape amount (X) is large and the escape amount (Z) is small. It is a figure explaining the case where a tool interferes with a workpiece | work at the time of the movement to the starting position Pc of the process cycle B. FIG. It is a figure explaining avoiding that a tool interferes with a workpiece | work at the time of the movement to the starting position Pc of the machining cycle B via the via point Pi for avoiding interference. It is a flowchart which shows the algorithm of the tool exchange operation | movement which concerns on this invention. It is a principal part block diagram of the numerical control apparatus which controls a lathe. It is a figure explaining the case where the tool change operation concerning the present invention is applied to a machining center. It is a figure explaining that the tool change operation | movement which concerns on this invention can be applied to the machining center which can change a tool in the arbitrary positions designated by the program. It is a figure explaining the tool post which mounts multiple types of tools. It is a figure explaining the conventional tool change operation.

The present invention solves the problem that the processing time becomes long in a numerical control device that executes a processing program that combines a plurality of processing cycles with the tool change operation interposed therebetween. A new tool change position is automatically obtained from the protruding amount of the tool, and a tool change operation is performed at the new tool change position.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, about the structure which is the same as that of a prior art, or similar, it demonstrates using the same code | symbol.

  FIG. 1 is a schematic view of a tool post on which a plurality of types of tools are mounted. FIG. 1 (a) is a front view thereof, and FIG. 1 (b) is a side view thereof. As shown in FIG. 1A, four tools T1 to T4 are mounted. The tool T1, the tool T2, the tool T3, and the tool T4 have different lengths in the axial direction of the tool axis as can be seen from FIG. 1 (a), and the length in the direction perpendicular to the tool axis as can be seen from FIG. 1 (b). It is also different. Reference symbol R is a reference position of the tool post 10. Reference numeral 12 denotes a central axis of the tool. The tool post 10 can be rotated clockwise or counterclockwise by driving means (not shown) about the tool post rotation center axis 14 passing through the tool post reference position R as a central axis. The turret type lathe is a machine tool having a turning tool post 10 called a turret as shown in FIG. 1, and is used by attaching a plurality of tools to the tool post 10 and turning the tool. Switch tools. Since the tool can be changed by rotating the tool post 10 which is a turret, the time required for changing the tool can be shortened.

  FIG. 2 is a diagram for explaining a tool changing operation according to the present invention. A lathe controlled by a numerical control device (not shown) includes a workpiece fixing means 20 called a chuck for detachably fixing the workpiece 22, and a tool post 10 (see FIG. 1) on which tools T1 to T4 are mounted. The workpiece fixing means 20 holds the workpiece 22 along the main axis (Z axis in FIG. 2), and is rotationally driven by a main shaft motor described later. Further, the tool post 10 is provided so as to be movable in the Z-axis direction and the X-axis direction orthogonal to the Z-axis direction by servo motors of respective axes described later (see FIG. 10). The workpiece 22 is machined by the tool T1 and then machined by the tool T3 by a machining program executed by a numerical control device described later. Processing with the tool T1 is a processing cycle A, and processing with the tool T3 is a processing cycle B.

The tool change operation according to the present invention is applied to the tool change of the tools T1 to T4 mounted on the tool rest 10.
When the machining cycle A using the tool T1 is completed, the tool rest 10 starts moving toward the tool exchange position Pa in the same manner as in the prior art in order to exchange the tool to the tool T3 used in the machining cycle B. The tool change position Pa is a position programmed in the machining program. Alternatively, a preset tool change position of the lathe shown in FIG. 2 can be handled as the tool change position Pa.

  When the tool post 10 is rotated by the tool changing operation, the spatial position of the tool T1 currently used, the tool T3 to be used next, and the tool T2 attached therebetween is changed. Therefore, in the present invention, even if the tool post 10 is rotated, the tool T1, the tool T2, and the tool T3 are moved to a position where the tool replacement area 24 does not interfere (automatically determined tool change position Pb). Tool change is performed. The direction of rotation of the tool rest 10 rotates in a direction where the rotation angle of the tool rest 10 is small to reach the tool used in the next machining cycle. Alternatively, the rotation may be specified in one direction.

  The tool change position Pb is sequentially calculated as to whether or not the tool interferes with the tool change impossible area 24 at every cycle in which the control to move to the tool change position Pa of the tool post 10 is performed, and the position at which no interference occurs is obtained as the tool change position Pb. It may be obtained in advance by numerical calculation. In the flowchart to be described later, an algorithm for calculating sequentially is described.

  After the tool change from the tool T1 to the tool T3 is completed, the tool moves from the tool change position Pb to the start position Pc of the machining cycle B. At this time, the tool post 10 is rotated in the direction of the tool T1, the tool T2, and the tool T3.

The automatically determined new tool change position Pb is calculated based on the maximum protrusion amount of the tool T1 currently used, the next tool T3 to be used, and the tool T2 attached therebetween, and the protrusions of other tools It does not depend on the amount. As a result, the amount of movement from the end position P of the machining cycle A to the automatically determined new tool change position Pb is smaller than the amount of movement to the programmed tool change position Pa, and the turret necessary for the tool change operation is reduced. Movement can be minimized. Further, the automatically determined tool change position Pb is automatically recalculated from the protruding amount of the new tool even after the tool change, so that manual teaching is unnecessary.
As described above, according to the present invention, it is possible to save time and labor for determining the tool change position and to significantly reduce the time required for the tool change operation.

FIG. 3 is a diagram for explaining a tool post on which a plurality of types of tools are mounted, and for explaining the dimensions of the tool shown in FIG. 13 in more detail. A machining program M including a machining cycle A, a machining cycle B, and a tool change operation will be described as an example.
Machining program M
Machining cycle A
Tool change command
Processing cycle B
As shown in the figure, four types of tools, that is, a tool T1, a tool T2, a tool T3, and a tool T4 are attached (attached) to the tool post 10. In the machining cycle A, the tool T1 is used, and in the machining cycle B, the tool T3 is used. Here, it is assumed that the replacement operation from the tool T1 to the tool T3 is performed in the order of T1, T2, and T3. In the present invention, it is not excluded that the battery is exchanged in the reverse direction.

  As shown in FIG. 3 (a), the length in the tool axis direction from the tool rest reference position R to the tool attachment portion of the tools T1 to T4 is Tx, and the distance from the tool attachment portion to the tool tip of the tools T1 to T4 is shown. The lengths in the tool axis direction are T1x to T4x, respectively. Projection amounts T1Lx, T2Lx, T3Lx, and T4Lx in the tool axis direction from the tool post reference position R to the tool tip for each of the tool T1, tool T2, tool T3, and tool T4 are calculated by the following equations.

T1Lx = T1x + Tx
T2Lx = T2x + Tx
T3Lx = T3x + Tx
T4Lx = T4x + Tx
Further, as shown in FIG. 3B, the length in the direction perpendicular to the tool axis of each of the tools T1 to T4 from the tool post reference position R (in other words, the direction parallel to the tool post rotation center axis 14). Alternatively, the radius of the tool is regarded as a protrusion amount T1Lz to T4Lz in the direction perpendicular to the tool axis 12.

  In the tools T1 to T4, the tool axes 12 are on the same plane in the tool post 10, and the tool axes 12 intersect at the tool rest reference position R. The tool post 10 is rotated by a driving means (not shown) with the tool post rotation center axis 14 passing through the tool post reference position R as a rotation center. As the rotation direction, a clockwise direction or a counterclockwise direction can be selected by a command, or an optimal rotation direction is automatically selected so that tool change is executed in the shortest time.

Next, the automatically determined tool change position Pb will be described.
FIG. 4 is a diagram for explaining the coordinate position of the automatically determined tool change position Pb.
The machining cycle A ends when the tool rest 10 is located at the end position P. After that, when a tool change command is executed in accordance with the machining program, movement is started from the end position P to the tool commanded tool change position Pa in order to change to the tool T3 used in the next machining cycle B.

  At this time, the X-axis machine coordinate position of the tool post reference position R movable in the X-axis direction is set to Xr, the X-axis machine coordinate value indicating the tool non-changeable region 24 is set to Xi, and each tool protrudes in the tool axis direction. If the maximum value of the quantities T1Lx, T2Lx, and T3Lx is TmaxLx, the X-axis mechanical coordinate value Xr that exits from the tool non-changeable region 24 is obtained by the following equation, and the tool can be changed by considering the clearance Qx. The machine coordinate value Xbr of the X axis is uniquely determined as follows. In FIG. 3, TmaxLx is T2Lx of the tool T2. An appropriate value is selected for the gap Qx.

Xr> Xi + TmaxLx
Xbr = Xi + TmaxLx + Qx
= Xi + T2Lx + Qx
Similarly, the Z-axis machine coordinate value of the tool post reference position R movable in the Z-axis direction is Zr, the Z-axis machine coordinate value indicating the tool non-changeable region is Zi, and the tool axis of each tool is perpendicular to the tool axis. If the maximum value of the protrusion amounts T1Lz to T3Lz is TmaxLz, the Z-axis mechanical coordinate value Zr that exits from the tool non-changeable area is obtained by the following equation, and the Z-axis that allows tool change by considering the gap Qz The machine coordinate value Zbr of is uniquely determined as follows. In FIG. 3, TmaxLz is T3Lz of the tool T2. An appropriate value is selected for the gap Qz.

Zr = Zi + TmaxLz
Zbr = Zi + TmaxLz + Qz
= Zi + T3Lz + Qz
The tool post 10 moves to at least a position away from the machine coordinate value Xbr of the X axis where the tool can be changed, or at least a position away from the machine coordinate value Zbr of the Z axis where the tool can be changed, and stops. However, as shown in FIG. 4, the automatically determined tool change position Pb may be at least a machine coordinate value Xbr and at least a position away from the machine coordinate value Zbr.
Thereafter, the tool is changed from the tool T1 to the tool T3 and moved from the tool change position Pb to the start position Pc of the next machining cycle B.

Next, the movement of the tool rest 10 will be described for each case.
<When the amount of relief in the X-axis direction to the programmed tool change position Pa is small and the amount of relief in the Z-axis direction is large>
FIG. 5 is a diagram for explaining the automatically determined tool change position Pb when the relief amount (X) is small and the relief amount (Z) is large.
At this time, the tool post 10 reaches the Z-axis machine coordinate value Zbr at which the tool can be changed and is programmed before reaching the position where the tool change is possible up to the X-axis machine coordinate value Xbr. The axis movement to the tool change position Pa is completed. This position is set as an automatically determined tool change position Pb.
The tool is changed from the tool T1 to the tool T3 at the automatically determined tool change position Pb, and then moved from the tool change position Pb to the start position Pc of the next machining cycle B.

<When the X-axis direction relief amount to the programmed tool change position Pa is large and the Z-axis direction relief amount is small>
FIG. 6 is a diagram for explaining the automatically determined tool change position Pb when the relief amount (X) is large and the relief amount (Z) is small.
At this time, the tool post 10 reached the X-axis machine coordinate value Xbr capable of tool change before reaching the position distant to the Z-axis machine coordinate value Zbr capable of tool change, and was programmed. The axis movement to the tool change position Pa is completed. This position is set as an automatically determined tool change position Pb.
At the automatically determined tool change position Pb, the tool is changed from the tool T1 to the tool T3 and moved from the tool change position Pb to the start position Pc of the next machining cycle B.

Next, the setting of the tool change impossible area 24 will be described. By inputting the workpiece 22 and the workpiece fixing means 20 which is a chuck for gripping the workpiece, the shape of the tailstock of the tool, and the like, the tool non-changeable region 24 can be set.
Alternatively, the tool change impossible region once set can be output as data to an external device and input from the external device, and the tool change impossible region 24 set in the past can be easily reproduced.

FIG. 7 is a diagram for explaining a case where the tool interferes with the workpiece when the machining cycle B moves to the start position Pc.
Even if the tool is changed at the automatically determined tool change position Pb, the tool T3 may collide with the workpiece 22 when the tool T3 is moved to the start position Pc of the machining cycle B. As shown in FIG. 7, in the case of the positional relationship between the automatically determined tool change position Pb and the start position Pc of the machining cycle B, the tool T3 is moved to the workpiece at the point 26 when moving from the tool change position Pb to the start position Pc. 22 is contacted.

  Therefore, as shown in FIG. 8, it is avoided that the tool interferes with the workpiece when moving to the start position Pc of the machining cycle B via the via point Pi for avoiding interference. In the case of the positional relationship between the automatically determined tool change position Pb and the start position Pc of the machining cycle B, for example, the machine coordinate value of the Z axis that allows the tool change once in the Z axis direction from the tool change position Pb. It is possible to move to the start position Pc via a waypoint Pi for avoiding interference, which is a point moved to Zbr. Or you may move to the starting position Pc via another route, such as moving to the starting position Pc via the tool change position Pa originally programmed. The shape of the workpiece 22 can use the data input when setting the tool non-changeable area described in the setting of the tool non-changeable area.

  In the tool change operation including the move command to the tool change position, the program-commanded move command to the tool change position Pa can be updated to the move command to the automatically determined tool change position Pb shown in FIG. And Also, when there is a via point Pi for avoiding interference shown in FIG. 8, it is updated with a command including movement to the via point Pi.

FIG. 9 is a flowchart showing an algorithm of a tool change operation according to the present invention. Hereinafter, it demonstrates according to each step. In the process shown in the flowchart below, the current position is the end position P.
[Step SA100] The maximum protrusion amount TmaxLx in the tool axis direction and the tool axis of the currently used tool, the next tool to be used, and the tool arranged between those tools in the turret And the maximum protrusion amount TmaxLz in the vertical direction is calculated.
[Step SA101] Start moving in the commanded tool change position direction Pa.
[Step SA102] It is determined whether or not the condition A or the condition B is satisfied. If satisfied, the process proceeds to step SA103, and if not satisfied, the process returns to step SA101. Condition A: Xr> Xi + TmaxLx
Condition B: Zr> Zi + TmaxLz
However,
Xr: Tool post reference position R (X axis)
Xi: Tool change impossible area (X axis)
TmaxLx: Maximum protrusion amount in the tool axis direction Zr: Tool post reference position R (Z axis)
Zi: Non-tool changeable area (Z axis)
TmaxLz: Maximum protrusion amount in the direction perpendicular to the tool axis [Step SA103] End the axis movement.
[Step SA104] The tool is changed.
[Step SA105] It is determined whether or not the workpiece and the blade interfere with each other when moving from the automatically determined tool change position Pb to the next start position Pc. If there is an interference, the process proceeds to Step SA106. Shifts to step SA109.
[Step SA106] A via point Pi for avoiding interference is calculated.
[Step SA107] The via point Pi is inserted as the next movement command before the movement command to the start position Pc.
[Step SA108] Move to via point Pi.
[Step SA109] Move to the start position Pc and end the process.

  FIG. 10 is a principal block diagram of a numerical controller for controlling the turret type lathe. A control signal is sent from the numerical controller 50 to an X-axis drive motor 51 and a Z-axis drive motor 52 that move the tool post 10 in the X-axis direction and the Z-axis direction. In addition, a control signal is sent to the turret index motor 53 that rotates the tool post 10 in order to perform a tool changing operation so that a tool necessary for the machining cycle can be selected. Then, after the tool is changed to a tool suitable for the machining cycle, a control signal is also sent to the spindle motor 54 for the spindle for rotating the workpiece around the spindle. The program described with reference to the flowchart is stored in the numerical controller 50, and the tool change operation according to the present invention is performed by the machining program executing.

  Although the present invention has been described above using the turret type lathe as an example, the tool changing operation according to the present invention can be applied to machine tools other than the turret type lathe. Here, a case will be described in which the turret is rotated at an arbitrary position and applied to a tool changeable machining center (MC) or a tool changeable machining center (MC) at an arbitrary position designated by a program.

<MC that allows tool change by rotating the turret at an arbitrary position>
FIG. 11 is a diagram illustrating a case where the tool change operation according to the present invention is applied to a machining center. In addition, since the concept of invention is the same, the code | symbol of a tool, the dimension of a tool, etc. are demonstrated using the same code | symbol as description of the above-mentioned lathe. The workpiece 22 fixed to the table 28 is processed by a tool attached to the turret 16. The machining program M includes a machining cycle A, a machining cycle B, and a tool change operation. In the machining program M, after the machining cycle A is completed, the tool is moved to an arbitrary position commanded by the program and the tool is changed. After the tool change, the machining cycle B is started.

Machining program M
Machining cycle A
Tool change command Machining cycle B
Tools T1, T2, T3, and T4 are attached to (attached to) the turret 16, the tool T1 is used in the machining cycle A, and the tool T3 is used in the machining cycle B. The turret 16 corresponds to the tool post 10 in the description of the turret type lathe (see FIG. 1).
It is assumed that the tool change operation from the tool T1 to the tool T3 is changed in the order of T1, T2, and T3. As shown in FIG. 11, the length in the tool axis direction from the turret reference position R to the tool attachment part of the tool T1 to the tool T4 is Tz, and the tool axis from the tool attachment part to the tool tip of the tool T1 to the tool T4 Assuming that the lengths in the directions are T1z to T4z, respectively, the protrusion amount T1Lz in the tool axis direction from the turret reference position R to the tip of the tool T1 in the tool T1 is calculated by the following equation.
T1Lz = T1z + Tz
Similarly, protrusion amounts T2Lz to T4Lz in the tool axis direction from the turret reference position R to the tips of the tools T2 to T4 are also calculated.

  When a tool change command is issued after the end of the machining cycle A, movement is started from the end position of the machining cycle A to the programmed tool change position in order to change to the tool T3 used in the next machining cycle B.

  At this time, the Z-axis machine coordinate value of the turret reference position R movable in the Z-axis direction is Zr, the Z-axis machine coordinate value indicating the tool non-changeable area is Zi, and the protrusion amount T1Lz of each tool in the tool axis direction If the maximum value of T2Lz and T3Lz is TmaxLz (= T2Lz), the machine coordinate value Zr of the Z axis that exits from the tool non-changeable area is obtained by the following equation, and tool change is possible by considering the gap Qz The machine coordinate value Zbr of the Z axis is determined as follows.

Zr> Zi + TmaxLz
Zbr = Zi + Tmax + Qz
= Zi + T2Lz + Qz
The turret moves to a Z-axis machine coordinate value Zbr where the tool can be changed and stops. Thereafter, the tool is changed from the tool T1 to the tool T3 and moved from the tool change position to the start position of the next machining cycle B.

<MC that allows tool change at an arbitrary position specified by the program>
FIG. 12 is a diagram for explaining that the tool change operation according to the present invention can be applied to a machining center capable of changing tools at an arbitrary position designated by a program.
The machining program M includes a machining cycle A, a machining cycle B, and a tool change operation. In the machining program M, after the machining cycle A is completed, the tool is moved to an arbitrary position commanded by the program and the tool is changed. Then, after the tool change, the machining cycle B is started.
Machining program M
Machining cycle A
Tool change command Machining cycle B
In the machining cycle A, the tool T1 is used, and in the machining cycle B, the tool T3 is used. Tools necessary for the machining process are mounted on the spindle head 18. In FIG. 12A, the tool T <b> 1 used for the machining cycle A is attached to the spindle head 18. In FIG. 12 (b), the tool T 3 used in the machining cycle B is mounted on the spindle head 18.

In the exchange operation from the tool T1 to the tool T3, the tool T3 is moved to the spindle position by a movable tool changer (not shown) and is exchanged. As shown in FIG. 12, the length in the tool axis direction from the Z-axis reference position R to the tool attachment portion of the tool T1, tool T3 is Tz, and the tool axis from the tool attachment portion to the tool tip of the tool T1, T3 When the lengths in the direction are T1z and T3z, respectively, the protrusion amount T1Lz in the tool axis direction from the Z-axis reference position R to the tip of the tool T1 in the tool T1 is calculated by the following equation.
T1Lz = T1z + Tz
Similarly, the protrusion amount T3Lz in the tool axis direction from the Z-axis reference position R to the tip of the tool T3 is also calculated.

  When a tool change command is given after the end of the machining cycle A, in order to change to the tool T3 used in the next machining cycle B, the movement is started from the end position of the machining cycle A to the programmed tool change position. . The machine is a machine that can program the tool change position at an arbitrary position, not a unique position unique to the machine.

  At this time, the Z-axis machine coordinate value of the Z-axis reference position R is Zr, the Z-axis machine coordinate value indicating the tool non-changeable area is Zi, and the maximum values of the protrusion amounts T1Lz and T3Lz of the tools in the tool axis direction Is set to TmaxLz (= T3Lz), the Z-axis machine coordinate value Zr that exits from the non-tool changeable region is determined by the following equation, and the Z-axis machine coordinate value Zbr that allows tool change by considering the gap Qz. Is uniquely determined as follows. The Z-axis reference position R corresponds to the tool post reference position R in FIG.

Zr> Zi + TmaxLz
Zbr = Zi + TmaxLz + Qz
= Zi + T3Lz + Qz
The Z-axis moves and stops after the machine coordinate value Zbr of the Z-axis that allows tool change. Thereafter, the tool is changed from the tool T1 to T3 and moved from the tool change position to the start position of the next machining cycle B.

DESCRIPTION OF SYMBOLS 10 Tool post 12 Tool axis 14 Tool post rotation center axis 16 Turret 18 Spindle head 20 Work fixing means 22 Work 24 Tool non-changeable area

Pa Programmed tool change position Pb Automatically determined tool change position Pc Start position of machining cycle B R Reference position

Claims (3)

A tool turret or spindle head having a rotatable turret with a plurality of tools mounted thereon, and a tool by rotating the turret at a tool change position commanded by a machining program or a tool change position preset in the machine In a control device of a machine tool provided with a tool changer for indexing a predetermined position,
An area setting means for setting a tool non-changeable area, which is an area in which the tool interferes with other structures and cannot be changed.
A protrusion amount obtaining means for obtaining a protrusion amount which is a distance from a reference position of the tool post or the spindle head to a tip of each tool mounted on the tool rest or the spindle head;
In the path of movement from the end position of the machining process before the tool change to the tool change position, the tool currently used, the next tool to be used, the maximum protrusion amount of the tool between them, and the tool change impossible area And a means for obtaining a position at which the tool does not interfere with the tool non-changeable area as a new tool change position when performing a tool change,
With
When a tool change command is issued by the machining program, the turret is moved from the machining end position of the machining step before the tool exchange to the new tool exchange position determined by the means, and the turret is rotated to rotate the tool. A machine tool control device characterized in that the tool is indexed at a predetermined position and the tool is changed. An interference avoidance path obtaining means for obtaining an interference avoidance path in which the tool and the workpiece do not interfere with each other in the path moving from the new tool replacement position to the start position of the next machining step programmed by the machining program;
2. The machine tool control device according to claim 1, wherein the machine tool control apparatus moves to a start position of a next machining step through an interference avoidance path obtained by the interference avoidance path acquisition unit. Updating means for updating the machining program as a command to move the new tool exchange position and the interference avoidance path to a tool exchange position and a start position of the next machining step;
The machine tool control device according to claim 1, comprising:

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