JP4796936B2 - Processing control device - Google Patents

Description

  The present invention relates to a machining control device that controls a machining machine that machines a workpiece, and a program thereof.

  Conventionally, a numerical control device that controls a machine tool or the like analyzes a NC code of a previously created NC program and outputs position data and speed data as command data to a motor control device to process a workpiece. It is configured. Such an NC program is directly input from the operation panel of the numerical control device, or a shape to be processed into the CAM is input, and the NC program is automatically generated from the CAM and read into the numerical control device.

In recent years, with the spread of 3D CAD, the design of complex finished shapes has been performed by 3D CAD, and complex finished shapes have been output as solid data from 3D CAD. In the conventional CAM, inputting a complicated shape as defined by solid data is very time-consuming work, so it is difficult to generate NC data for processing a complicated shape. However, there has been proposed a method for automatically generating an NC program for machining a complex shape as defined by solid data by receiving solid data output by 3D CAD with CAM and generating a tool trajectory. (For example, Patent Document 1).
Japanese Patent Laid-Open No. 2003-295917

  In this way, thanks to the ability to output NC programs directly from 3D solid data with CAM, NC programs can be automatically generated even for complex machining shapes, which is burdened by workers. Was greatly reduced.

However, NC programs generated from CAM based on solid model data are often long because data that approximates a straight line by dividing a tool trajectory for machining a complex shape into small line segments is output. , It takes time for the CAM to generate the NC program. In addition, although the numerical control device decodes the NC program and calculates the command value for instructing the movement amount of each axis of the processing machine, it takes time for the numerical control device to decode the long NC program. The working efficiency from the generation of the tool trajectory by CAM to the machining is reduced.

Furthermore, in order to output the approximated by a straight line where the tool path in the CAM is a curve portion, it is necessary to divide the much smaller segments in order to maintain the finish precision, it is limited to the operation speed of the numerical controller As a result, an instruction issued from the numerical controller to the servo of the processing machine may not be able to keep up with the movement of the tool. Therefore, it cannot be divided into very small line segments.

  Therefore, an object of the present invention is to provide a machining control device and a program for reducing the time from generation of a tool locus to machining and improving machining accuracy.

The processing control device of the present invention is a processing control device that controls a processing machine that moves a processing position in which a tool processes a workpiece in a plurality of axial directions,
Tool path storage means for storing a tool path for processing the workpiece into a predetermined shape;
Processing speed storage means for storing a processing speed at which the tool processes the workpiece;
A division trajectory calculating means for dividing the tool trajectory at a portion where the curvature of the tool trajectory is small and dividing the tool trajectory at a small interval as the curvature of the tool trajectory increases;
As axis control data, each axis position on the division trajectory when the tool is moved on each division trajectory at a speed according to the machining speed and the time change of the speed in each axial direction is processed. Axis control data calculation means to be obtained;
An output means for outputting the axis control data of each divided locus is provided in the drive unit of the processing machine that moves the machining position on the divided locus while changing the speed in each axis direction according to the axis control data. It is a feature.

The program of the present invention is a computer,
A tool trajectory for processing the workpiece into a predetermined shape using a processing machine that moves a processing position where the tool processes the workpiece in a plurality of axial directions is divided at a large interval in a portion where the curvature of the tool trajectory is small. A divided trajectory calculating means for obtaining a divided trajectory divided at a small interval as the curvature of the tool trajectory increases;
Each axis position on the division trajectory when the tool is moved on each division trajectory at a speed according to the machining speed stored in advance and the workpiece is machined, and the time change of the speed in each axis direction Axis control data calculation means to be obtained as axis control data;
The drive unit of the processing machine that moves the machining position on the division trajectory while changing the speed in the direction of each axis according to the axis control data functions as an output unit that outputs the axis control data of each division trajectory. It is what.

  “Axis control data” refers to data for controlling each axis when the machining position of the tool is moved according to the division trajectory.

  The “speed according to the machining speed” refers to a speed at which the tool is moved on the divided trajectory so as to be close to the machining speed, and includes a case where the speed is not the same as the machining speed.

  Further, the axis control data calculation means may determine the time change of the speed in each axis direction at a predetermined time interval.

The apparatus further comprises parameter storage means for storing parameters relating to the processing accuracy of the processing machine,
The division trajectory calculation means may change an interval for dividing the tool trajectory according to the parameter.

  “Parameters related to the processing accuracy of the processing machine” refers to parameters for adjusting the processing accuracy in accordance with physical characteristics that depend on the processing machine, such as moment of inertia and rigidity, for example, parameters related to acceleration and jerk.

  Further, the axis control data calculating means is based on the parameter and is predicted to have a large curvature of the division locus at the machining position and cannot be machined along the division locus when machining is performed at the machining speed. Then, you may obtain | require the speed | rate of each said axial direction so that it may become smaller than the said processing speed.

  According to the present invention, by generating the axis control data for controlling the speed and position of each axis of the processing machine and outputting it to the drive unit of the processing machine, in divided trajectory units obtained by dividing the tool path according to the curvature, Since the processing machine can move the processing position along the processing trajectory without approximating the processing trajectory with a minute line segment as in the prior art, a complicated shape can be processed with high accuracy. In addition, since an NC program approximated by a minute line segment is not output as in the prior art, it is not necessary to generate and analyze a long NC program, so that time can be shortened.

  By changing the interval at which the tool path is divided according to the parameters relating to the processing accuracy, it is possible to accurately process the tool path so that the finishing accuracy can be obtained.

  In a portion where the curvature of the division trajectory at a machining position is large and machining is performed along the division trajectory when machining is performed at the machining speed, axis control data that is smaller than the machining speed is generated. Therefore, it can process without deviating from a tool locus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a machining system including a machining control device of the present invention.

  A machining system 1 according to the present invention includes a CAD device 2 that creates a machining shape, a machining control device 3 that controls a machining machine, a machining machine 4 that sets a workpiece (work) on a table and works the workpiece with a tool, Consists of. The CAD device 2 and the machining control device 3 are connected by a network 5.

  The processing machine 4 includes a main shaft 41 to which a tool is attached, a table 42 on which a workpiece is installed, a feed shaft (not shown) that moves the table, and a drive unit 45 that drives each shaft (main shaft, feed shaft). Prepare. Usually, the main axis is an axis for transmitting cutting power and is represented as a Z axis, and feed axes for moving the table 42 are represented as an X axis and a Y axis.

  As shown in FIG. 2, the drive unit 45 includes an axis control data receiving unit 46 that receives axis control data A for controlling each axis from the machining control device 3, and a movement signal for the Z axis that is the main shaft 41 according to the axis control data A. And a signal generator 47 for generating movement signals of the X and Y axes, which are the feed axes 43 and 44 of the table 42, a spindle amplifier 48 for transmitting the generated signal to the motor 48a for driving the spindle, and driving the feed axis And a servo amplifier 49 for transmitting the generated signal to the motors 49a and 49b. In FIG. 2, a rotary motor is shown, but the same applies to a linear motor. Further, although there are servo amplifiers 49 on each of the X axis and the Y axis, they are shown as one in the block diagram of FIG. 2 for convenience.

  The machining control device 3 includes a high-performance microcomputer and a memory. The microcomputer executes a program stored in the memory to drive each of the X axis, the Y axis, and the Z axis. A is generated. The program is preferably stored in a non-rewritable memory such as a ROM so that the program is not rewritten due to the influence of noise generated from the processing machine 4, but the program is affected by the noise generated by the processing machine 4. If the configuration does not exist, the program may be loaded into a rewritable memory and executed.

  The CAD device 2 is realized by executing a CAD program read into an auxiliary storage device of a general-purpose computer (for example, a workstation). The CAD apparatus 2 according to the present embodiment outputs a workpiece machining shape input by an operator as data of a three-dimensional solid model M.

As shown in FIG. 3, the processing control unit 3, various parameters, processing speed F, the offset value offsetting the machining shape d, an operation panel for inputting such pick-feed Pick a distance for moving the tool for machining a workpiece 31, parameter storage means 311 for storing set parameters, processing speed storage means 312 for storing processing speed F, offset value storage means 313 for storing offset value d, and pick feed for storing pick feed Pick a storage unit 314, an input hand stage 3 2 for inputting data of a solid model M generated by the CAD apparatus 2, a model data storage unit 321 for storing data of a solid model M, the offset value d min of the solid model M An offset shape generation means 33 for generating a shape (curved surface, curved line, etc.) offset by Tool trajectory generating means 34 for obtaining a tool trajectory for machining a workpiece from a faceted shape, tool trajectory storage means 341 for storing the tool trajectory, and split trajectory calculating means for obtaining a split trajectory obtained by dividing the tool trajectory according to the curvature of the tool trajectory 35, an axis control data calculation means 36 for obtaining axis control data A for each axis when the tool is moved on the divided trajectory at a speed according to the machining speed F, and an output means 37 for outputting the axis control data A to the drive unit. Is provided.

  The parameters include parameters related to physical characteristics such as maximum acceleration and jerk that depend on each processing machine, and control of each axis is performed according to the parameters. In addition, since the maximum acceleration, jerk, and the like vary depending on the attached tool, it is preferable to set parameters according to the tool.

  The offset shape generation unit 33 generates a shape obtained by offsetting the shape of the solid model M by the offset value d stored in the offset value storage unit 313. Normally, a finished shape is input to the CAD device 2 as a machining shape, and data of the solid model M of the finished shape is output from the CAD device 2. However, when machining with a tool attached to the processing machine 4, each axis is moved so that the center of the tool becomes the position of the tool, so that the surface shape of the finished shape is moved by moving the center of the tool. Then, the workpiece is cut by the tool radius more than the finished shape. Therefore, the tool radius is input as the offset value d, and the shape obtained by offsetting the surface shape of the solid model M is obtained. For example, when the surface shape S0 of the solid model M as shown in FIG. 4 is processed using a ball end mill, the surface shape S0 is offset in the normal direction t by an offset value d (hereinafter referred to as offset). Shape).

  The tool trajectory generating means 34 generates a tool trajectory for moving the tool on the offset shape S1. Here, the case where a workpiece is machined by contour machining will be described. When machining the workpiece, as shown in FIG. 5, the workpiece is cut while moving the tool along the intersection line L obtained by cutting the offset shape S1 on the contour plane Q parallel to the XY plane. Carving while moving the contour plane Q in the Z-axis direction (up → down) with a constant pick feed Pick.

The pick feed Pick is a value that is suitable for machining according to the tool diameter and workpiece material, is input from the operation panel 31 and stored in the pick feed storage means 314, and a pick having a specified contour plane Q parallel to the XY plane is designated. The tool trajectory is obtained by calculating the intersection line L with the offset shape S1 while moving the feed pick. An intersection line L between the contour plane Q and the offset shape S1 is represented by a parametric curve such as a B-spline, and the parametric curve is stored in the memory (tool path storage means 341) as a tool path.

  Alternatively, an intersection line between the plane parallel to the ZX plane and the YZ plane and the offset shape S1 may be obtained, and the plane may be moved by a constant pick feed in the X-axis direction or the Y-axis direction and carved. . In addition, the tool path may be generated according to a processing method such as scanning processing or spiral processing.

  The division trajectory calculating means 35 obtains a divided trajectory obtained by dividing the tool trajectory L according to the curvature of the tool trajectory L. The processing machine 4 processes the workpiece by moving the processing position of the tool while controlling the speed of each axis between the two specified points. However, in the portion where the curvature of the tool locus L is large, the moment of inertia of the processing machine 4 is processed. In some cases, it is difficult to move the machining position of the tool along the tool path L due to the influence of rigidity and the like. Therefore, it is preferable that the tool locus L connecting the two points designated to the processing machine 4 does not deviate greatly from the straight line. Accordingly, the curvature of the tool locus L is obtained, and as shown in FIG. 6, the tool locus L is divided at a large interval when the curvature is small, and is divided at a small interval as the curvature increases, and a point P1 on the tool locus L is obtained. , P2, P3,..., Pi, Pi + 1,..., And divided into a plurality of divided trajectories l1, l2, l3,.

  That is, when the curvature of the tool locus is small (curvature is close to 0), the processing machine is instructed to process data having a large divided locus l, and when the curvature is large, the short divided locus l is machined. Such data is instructed to the processing machine.

  The axis control data calculation means 36 calculates each of the divided trajectories l when the tool is moved at the specified machining speed F along the respective divided trajectories l 1, l 2, l 3,. The axis position and the time change of the velocity in each axis direction obtained at a predetermined time interval are obtained as axis control data A. The axis control data A only needs to include at least one axis position on the division locus as each axis position on the division locus. For example, if the axis control data A records the position of the starting point on the divided locus l and the speed change of each axis when moving along the divided locus, the axis follows the speed change from the position of the starting point. By controlling each axis in this way, the tool can be moved to the machining position along the division locus l.

  For example, in order to machine a workpiece at a designated machining speed F along the division trajectory l as shown in FIG. 7, the machining position of the tool is moved in the tangential direction of the division trajectory 1 at the machining speed F. . In other words, the machining speed F is divided into X, Y, and Z components of the tangent vector of the division trajectory l, the X axis is moved by the velocity component in the X direction, the Y axis is moved by the velocity component in the Y direction, and the Z axis Is moved by the velocity component in the Z direction. In FIG. 7, the velocity components of each axis at the starting point position P1 on the divided locus l are (V1x, V1y, V1z), and the velocity components of each axis at the ending point position P2 are (V2x, V2y, V2z) and Therefore, the speed of each axis is changed from V1x → V2x, V1y → V2y, and V1z → V2z while moving each axis from the position P1 to P2. Further, in order to move the tool along the division locus l, it is necessary to change the speed of each axis at short time intervals so that the traveling direction of the tool is in the tangential direction of the division locus.

Therefore, as shown in FIG. 8, a speed curve representing the time change of the speeds Vx, Vy, and Vz for moving the respective axes when the tool is moved at the machining speed F on each divided trajectory l is obtained. FIG. 8 shows a case where there is no movement in the Z direction and there is a movement only in the XY plane. By controlling the speed of each axis so as to follow this speed curve, the machining position can be moved along the division locus l. Therefore, for example, the speed of each axis at the point obtained by dividing the speed curve of each axis at a short constant time interval Δt and the starting point of the divided locus l are recorded in the axis control data A. Further, since the integral value of the velocity curve from time T0 to time Tn is the distance moved from time T0 to time Tn, the position of each axis at time Tn is at the start point P0 of the divided locus l at the velocity curve T0. The position of each axis is obtained by adding the integral value between ~ Tn.

  The division trajectory calculation means 35 divides the tool trajectory so that the division trajectory does not greatly deviate from the straight line. However, since the processing machine 4 has a limit on the maximum acceleration and jerk, the specified machining speed F is maintained. There is a place where the machining position of the tool cannot be moved along the division locus l. Therefore, based on the parameters related to the maximum acceleration and jerk, the curvature of the division trajectory 1 at the machining position is large, and it is specified in the portion where it is predicted that machining cannot be performed along the division trajectory 1 when machining is performed at the machining speed. The speed in each axial direction is determined so as to be smaller than the machining speed F. Specifically, the acceleration and jerk when each axis is moved at the specified machining speed F are obtained, and the portion of the machining position that exceeds the maximum acceleration or maximum jerk of the processing machine 4 from the parameters is determined. Axis control data A is generated by determining the speed in each axial direction so that the moving speed is smaller than the machining speed F stored in the machining speed storage means 312 and does not exceed the maximum acceleration or the maximum jerk.

The signal generator 47 of the processing machine 4 generates a movement signal for each axis according to the speed of the axis control data, and outputs it to the spindle amplifier 48 and the servo amplifier 49. For example, as shown in FIG. 8, a change in speed is recorded in the axis control data at intervals of Δt, the movement speed in the X-axis direction is Vxi at time Ti, and the movement speed in the X-axis direction is at time Ti + 1. When Vx (i + 1), the movement signal is a servo amplifier 49 between time Ti and time Ti + 1 and the movement signal in which the movement speed in the X-axis direction changes from Vxi to Vx (i + 1). Output to. Similarly, when the movement speed in the Y-axis direction is Vyi at time Ti and the movement speed in the Y-axis direction is Vy (i + 1) at time Ti + 1, the movement signal is from time Ti to time Ti + 1. A movement signal is output to the servo amplifier 49 so that the movement speed in the Y-axis direction changes from Vyi to Vy (i + 1). In the example of FIG. 8 , since there is no movement speed in the Z-axis direction, no movement signal is output to the spindle amplifier 48. In this way, by changing the moving speed of each axis, the machining position can be moved from the start point position P1 to the end point position P2 along the division locus l.

  Here, the flow of machining a workpiece by the machining system 1 of the present invention will be described with reference to the flowchart of FIG.

When processing, the maximum acceleration, jerk, and the like vary depending on the processing machine 4 and the tool used. In order to achieve a certain degree of processing accuracy when performing processing, the control method must be adjusted according to the processing machine 4 and the tool used. Therefore, the operation panel 31 in the pressurizing Engineering control unit 3, by setting the various parameters relating to such maximum acceleration, jerk, and stored in the parameter storage unit 311 (S100).

The operator inputs the finished shape as a machining shape using the CAD device 2 (S200), and outputs the solid model M from the CAD device 2 based on the input shape (S201). The solid model M is transmitted to the machining control device 3 via the network 5, and the machining control device 3 receives the solid model M transmitted from the CAD device 2 by the input means 32 and stores it in the model data storage means 321 ( S101). Further, the operator inputs the machining speed F for machining the workpiece, the offset value d corresponding to the tool used for machining, and the pick feed Pick from the operation panel 31 of the machining control device 3, and machining speed storage means 312 and parameter storage means 311. The pick feed storage means 314 and the offset value storage means 313 are stored (S102).

  The machining control device 3 generates an offset shape S1 obtained by offsetting the solid model M by the offset value d by the offset shape generation means 33 (S103), and the tool trajectory generation means 34 above the offset shape S1 by pick feed Pick. A tool locus L is generated when machining a workpiece while moving a machining surface parallel to the XY plane in the Z-axis direction (S104). The generated tool path L is stored in the tool path storage unit 341.

  Next, the divided locus calculation means 35 obtains a divided locus 1 obtained by dividing the tool locus L according to the curvature of the tool locus L (S105). Further, the axis control data calculation means 36 generates axis control data A for moving the machining position along each divided locus 1 at a speed according to the designated machining speed F (S106).

  The output means 37 outputs the axis control data A of the divided trajectories l1, l2, l3,..., Li,. The axis control data receiving unit 46 of the driving unit 45 receives the axis control data A (S301), and generates a signal for driving each axis from the axis control data A according to the order received by the signal generating unit 47 to generate the spindle amplifier 48 and the servo. The signal is output to the amplifier 49 (S302). In this axis control data A, the change in speed of each axis is recorded at a constant time interval Δt from the start point of the divided trajectory, and the speed of each axis is measured from the start point of each divided trajectory l at a constant time interval Δt. By changing it, the machining position can be moved along the division trajectory l. A feedback mechanism that adjusts the speed of each axis so that the machining position does not deviate from the division trajectory l by changing the speed of each axis by the drive unit 45 and providing the processing machine 4 with an encoder that detects the position of each axis. The one provided is desirable.

  In the above-described embodiment, the offset method when machining using a ball end mill has been described. However, when machining using another type of tool such as a flat end mill, an offset shape corresponding to the offset method is obtained. That's fine.

  In the above-described embodiment, the case where the control is performed using the axis control data in which the speed change is recorded at a constant time interval has been described. However, as long as the time interval is determined, the time interval may not be constant.

  Moreover, although the case where the speed of each axis is recorded at a certain time interval has been described in the axis control data, the change in speed may be recorded.

  In the above-described embodiment, the case where the axis control data in which the speed change is recorded at a constant time interval is output to the drive unit has been described. However, the mathematical formula data representing the time change of the speed in each axis direction is used as the axis control data. You may make it change the speed of each axis | shaft according to the numerical formula output to the drive part and received by the drive part.

  As described above in detail, by generating control data for controlling the speed of each axis of the processing machine in units of divided trajectories obtained by dividing the tool trajectory according to the curvature, the processing machine is driven as before. Since a complicated shape can be machined without approximating the machining locus with very small line segments, machining can be performed with high accuracy. Conventionally, since it was once converted to NC data, it took time to decode the NC data. However, since control data is generated directly from the tool path, the time from shape input to machining can be shortened. Can do.

  In the present embodiment, the case where the solid model is input to the machining control device and the axis control data is generated has been described. However, the solid model is output from the CAD device to the CAM device, and the axis control is performed by the CAM device. Data may be generated and output to the machining control device.

  The CAM device is realized by reading and executing a program having a function of generating axis control data in an auxiliary storage device of a general-purpose computer (for example, a workstation). A program having the above functions is distributed via a recording medium or a network and installed in a computer.

Schematic configuration diagram of processing system Configuration diagram of the drive unit of the processing machine Configuration diagram of machining control device Diagram for explaining how to obtain the offset shape of the machining shape Diagram for explaining how to find the tool path The figure for explaining how to find the division trajectory by dividing the tool trajectory Diagram showing the relationship between division trajectory and machining speed Diagram showing speed change of each axis Diagram for explaining the operation of the machining system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing system 2 CAD apparatus 3 Processing control apparatus 4 Processing machine 5 Network 31 Operation panel 32 Input means 33 Offset shape generation means 34 Tool locus generation means 35 Division locus calculation means 36 Axis control data calculation means 37 Output means 41 Spindle 42 Table 43 , 44 Feed axis 45 Drive unit 46 Axis control data reception unit 47 Signal generation unit 48 Spindle amplifier 48a, 49a, 49b Motor 49 Servo amplifier 311 Parameter storage means 312 Processing speed storage means 313 Offset value storage means 314 Pick feed storage means 321 Model Data storage means 341 Tool path storage means

Claims (1)

A processing control device that controls a processing machine that moves a processing position in which a tool processes a workpiece in a plurality of axial directions,
Parameter storage means for storing the maximum acceleration as a parameter relating to the processing accuracy of the processing machine;
Tool trajectory storage means for storing the tool trajectory as a tool trajectory for machining the workpiece into a predetermined shape with a curve generated from a machining shape model;
Processing speed storage means for storing a specified processing speed at which the tool processes the workpiece;
A division trajectory calculating means for dividing the tool trajectory at a portion where the curvature of the tool trajectory is small and dividing the tool trajectory at a small interval as the curvature of the tool trajectory increases;
When machining the workpiece is moved on each divided path at the moving speed in accordance with the processing speed of the tool is the specified, and each axis position of the starting point on the dividing path, the divided trajectory a predetermined the moving speed of each axis direction acceleration of the tool in said each point the each point depending on the curvature of the divided track is determined so as not to exceed the maximum acceleration at each point divided by the time interval Delta] t, Axis control data calculation means for obtaining A as axis control data;
According to the axis control data , the machining position is changed along the division trajectory to the end point of the next division trajectory that is the end point of the division trajectory while changing the moving speed in the axial direction from the position of the start point on the division trajectory. The movement speed of each axis is changed so that the movement speed in the direction of each axis at the end point of the divided locus coincides with the movement speed in the direction of each axis at the position of the start point of the next divided locus. Output means for outputting the axis control data of each division trajectory to the drive unit of the processing machine,
The movement speed in each axial direction obtained at the predetermined time interval Δt is determined so that the tool moves in a tangential direction on the division trajectory, and the driving unit is configured to perform the predetermined control of the axis control data. The movement speed Vi in each axis direction at the time Ti obtained at the time interval Δt is the movement in each axis direction at the next time Ti + 1 (= Ti + Δt) until the next time Ti + 1 (= Ti + Δt). A machining control device characterized in that the moving speed in each of the axial directions is changed so as to be a speed Vi + 1.

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