JPH0620717B2 - Feeding speed converter for machining corner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a feed rate conversion device for a tool cutting edge in a work corner section, and particularly to a machining corner section that changes the intermediate speed stepwise in response to load fluctuations. The present invention relates to a feed rate converter.

[Conventional technology]

When machining with a milling cutter or end mill, etc., the machining end point at the corner of the work is set by the command of the machining program, and the feed speed of the tool edge stops the machining feed speed up to that point or converts it to the next feed speed. It is usually done. In such a case, in the machining program, only the machining width of the workpiece and the stop or the next feed rate are designated, and conventionally, the conversion is performed at once at the machining end point or the like.

[Problems to be solved by the invention]

In the above-mentioned conventional method, one of problems is how to set the feed width of the work machining width from the point where the tool edge approaches the corner to the machining end point. In the section of this work machining width, the load on the tool edge fluctuates, and if the feed rate remains constant, chipping accidents such as chipping accidents are caused,
However, if you send it at the lowest speed, the work time will be delayed and it will be inefficient.

The present invention was devised in view of such problems, and prevents a loss accident due to load fluctuation during cutting conversion and extends the life of the tool by giving optimum cutting conditions to the tool and extending the surface finish. It is an object of the present invention to provide a feed rate conversion device for a machining corner that improves the quality of the work and does not reduce the work efficiency.

[Means for solving problems]

In the present invention, as a means for solving the above problems, as shown in the basic configuration of FIG. 1, an entry start point, a machining end point and a tool cutting edge radius in a work corner are set by a machining program. In the feed rate conversion device of the machining corner section for converting the feed rate of the tool edge from the predetermined machining feed rate to the feed rate set at the machining end point, the load applied to the tool edge in the machining path of the work corner section In addition to obtaining the data that approximates the variation, a plurality of points at which the load fluctuates abruptly are obtained as the shift points of the feed rate from the approximated data, and the coefficient of the ratio distribution between the position of the shift points and the machining path is used. A certain distance coefficient and a feed rate coefficient, which is a coefficient of the ratio distribution of speed change to the change amount of the feed rate from the start point to the end point at the shift point, are set, and an actual feed rate coefficient is set. At the time of work, a machining path is obtained from the entry start point and the machining end point from the machining program, and the intermediate position point of the actual shift point is calculated for this machining path based on the tool cutting edge radius and the distance coefficient at the shift point. Then, the shift position point determining means for setting a plurality of values and the change amount of the feed speed at the start point and the feed speed at the end point are obtained from the machining program during the actual machining, and the shift point is determined with respect to the change amount of the feed speed. And a feed rate selecting means for calculating and instructing an actual intermediate feed rate at the intermediate position point on the basis of the feed rate coefficient. The machining program is the machining program memory 3
The data regarding the machining corner portion and the tool edge data therein are stored in the corner portion data memory 4.

[Action]

The shift position point determining means 1, as shown in FIG.
An intermediate position point of the feed speed conversion is set on a path from a position P1 where the tool edge T enters the corner portion of the work W to a position P5 where the tool tip radius D enters the corner portion of the work W and ends. The feed speed selection means 2 commands different intermediate feed speeds F4 to F0 for each section divided by these intermediate position points P1 to P5 in correspondence with the current position of the tool cutting edge. As shown in FIG. 1, the coordinate value of each intermediate position point determined by the shift position point change determining means 1 is once registered in the intermediate position point register 5 and then used in the feed speed selecting means 2, and The blade edge position of the tool is detected by the blade edge position detecting means 6 and used by the feed speed selecting means 2.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the embodiments and the drawings.

FIG. 3 is a block diagram showing an example of the configuration of a feed rate conversion device embodying the present invention. In FIG. 3, the feed rate conversion device comprises a gear shift position point determining means 1 for setting an intermediate position point for feed rate conversion in a path of a tool blade, and an intermediate feed rate which is different for each section divided by these intermediate position points. A feed rate selecting means 2 for giving a machining rate, a machining program memory 3 for storing a machining program, and a corner data memory for storing each data including a machining width of a work corner and a tool cutting edge radius for each step of the machining program. 4, an intermediate position point register 5 for registering the coordinate value of each intermediate position point determined by the gear shift position point determining means 1, a motor drive unit 6 as a blade edge position detecting means for detecting a tool blade edge position, and a host device. CPU 7 for controlling each of the above means also as a control unit of
And a display 8 with a keyboard and an input / output port 9 thereof.

Incidentally, FIG. 4 shows a variation curve that approximates the variation of the load applied to the tool cutting edge in the machining path of the work corner portion when machining the work corner portion, and the horizontal axis represents the machining path 100. And the distance coefficient, which is a coefficient of the ratio distribution of the machining path in the case of, the vertical axis represents the change in speed when the amount of change in the feed speed from the start point to the end point at the shift point is 10. It is a feed rate coefficient which is a coefficient of ratio distribution. In this approximate variation curve, a plurality of points on the working width where the load fluctuates abruptly are obtained as shift points, and the positions of these shift points are preset as distance coefficients of the intermediate position points, and the intermediate position points The feed rate coefficient on the variation curve approximate to the above is preset as the intermediate feed rate. Under such a premise, the gear shift point determining means 1 of the present embodiment obtains a machining path from an entry start point and a machining end point of a corner portion from a machining program at the time of actual machining, and from this machining path, the distance coefficient and the tool edge radius. Based on the above, a plurality of shift points are obtained and set as intermediate position points. Further, the feed speed selection means 2 obtains the amount of change in the feed speed at the start point and the feed speed at the end point from the machining program during the actual machining, and the feed rate coefficient at the speed change point with respect to this amount of change in the feed speed. Based on the above, the actual intermediate feed speed at the intermediate position point is calculated and instructed. Furthermore, in the present embodiment, since each data is processed by the biaxial coordinates of Z and Y, if the feed direction of the tool cutting edge has an angle α with respect to the X axis, that angle α must be used. First, the small calculation unit 10 is provided in front of the gear shift position point determining means 1, and based on the coordinate values of the machining start point Ps (Xs, Ys) and the machining end point Pe (Xe, Ye) set in the machining program. , To calculate. And the distance calculation in the route direction is all cos
By multiplying by α and sin α, it is converted into an X value and a Y value.

The load of the tool changes only after the tool blade edge has begun to enter the work corner and has finished entering the edge radius D, as shown in FIG. 2, the first shift point P1 is As the entry point to the corner portion, the distance H from the shift point P1 to the machining end point Pe set in the machining program and the cutting edge radius D of the tool are registered in the corner data memory 4 for each program. In the first arithmetic circuit 11 in the shift position point determining means 1, the coordinate value X of the first shift point P1
1 and Y1 are calculated as X1 = Xe−H * cosα Y1 = Ye−H * sinα. The second to fourth shift points P2 to P4 are the second to fourth arithmetic circuits 12 to 14 in the shift position point determining means 1.
Then, with the first shift point P1 as the starting point, the ratio distribution based on the distance coefficient with respect to the tool tip radius D is: Xi = X1 + D * cosα * Ki (i = 2 to 4) Yi = Y1 + D * sinα * Ki ( i = 2-4). FIG. 4 (a) is a characteristic diagram of load fluctuation,
It is a variation curve that approximates the variation of the load applied to the tool cutting edge. The distance coefficient at the point (shift point) on the machining width where the load changes abruptly is the distance coefficient Ki (i = 2 to 4). That is, K2 = 0.1
5, K3 = 0.4 and K4 = 0.8 are set. Fifth shift point P
5 is the above processing end point Pe.

The coordinate values Xi and Yi of each shift position point Pi determined by the shift position point determining means 1 are temporarily stored in the intermediate position point register 5.

FIG. 5 is a flow chart showing an example of the feed speed selection operation when the machining is actually performed in the state where the gear shift position point is determined by the apparatus of the above embodiment. As shown in FIG. 5, an override instruction is issued, and the motor drive unit 6 as the blade edge position detecting means feeds back the real-time coordinate values Xi 'and Yi' of the blade edge position, and inserts it at the starting point P1 of the corner portion. When applied, the speed conversion of this embodiment is executed. Real-time coordinate value X of the cutting edge
i'and Yi 'are input to the feed speed selection means 2, and the comparison circuits 21 to 25 in the feed speed selection means 2 determine which section the cutting edge position is relative to the shift position point. For each section, using the characteristic diagram of the load fluctuation shown in FIG. 4 (a), the feed rate which is the coefficient of the ratio distribution of the speed change to the change amount of the feed speed from the start point to the end point at the shift point is used. Set the speed coefficient. That is, the difference between the machining feed rate Fs and the feed rate Fe at the machining end point Pe set by the machining program is multiplied by the feed rate coefficient (for example, 0.5, 0.75, 0.8, 1.0) corresponding to the intermediate position point. Intermediate feeding speeds F4 to F0 obtained by subtracting the values from the processing feeding speed Fs are set as shown in FIG.
Intermediate feed speeds F4, F3, F2, F1, corresponding to 25
Alternatively, either F0 is selected. The first intermediate feed speed F4 is naturally the machining feed speed Fs, and the fifth intermediate feed speed F0 is naturally the end feed speed Fe.

Further, in this embodiment, as a general shape of the corner portion,
The configuration for the one having the characteristics corresponding to FIG. 4 (a) is shown, but for the corner portion having the shape corresponding to FIG. 4 (b), the intermediate feed speeds F4 to F0 are set. The same effect can be obtained by changing the setting.

The feed speed selected as described above is used as it is for the motor drive control of the tool edge.

As described above, by using the feed rate conversion device embodying the present invention, it is possible to set the details of the program without any particular setting.
By only giving an override instruction, if the tool edge approaches the machining corner portion, it is automatically converted to the preset intermediate feed speed, and machining feed corresponding to the load fluctuation can be carried out.

〔The invention's effect〕

As described above, according to the present invention, it is possible to prevent a cutting edge accident due to a load change at the time of machining conversion, extend the life of the tool by giving optimum cutting conditions to the tool, and improve the element efficiency. It is possible to provide a feed rate conversion device for a machining corner portion that improves the quality of the finished surface.

[Brief description of drawings]

1 is a basic configuration diagram of the present invention, FIG. 2 is an explanatory diagram of a machining corner portion, FIG. 3 is a configuration diagram of one embodiment of the present invention, and FIG.
FIG. 5 is a characteristic diagram of load fluctuation, and FIG. 5 is a flowchart of speed selection operation. DESCRIPTION OF SYMBOLS 1; Gear position determining means, 2; Feed rate selecting means, 3; Machining program memory, 4; Corner data memory, 5; Intermediate position point register, 6; Blade edge position detecting means, 11 to 20; Arithmetic circuit , 21-25; comparison circuits.

Claims (1)

[Claims] 1. An approach start point at which machining of a work corner portion starts and a cutting speed of a tool starts to change from a predetermined machining feed speed to another feed speed, and a feed speed that has changed after machining of a corner portion has changed. Has a machining program in which a machining end point for returning to a predetermined machining feed rate and a tool cutting edge radius are input, and based on this machining program, from a predetermined machining feed rate to a feed speed set at the machining end point In the feed rate converter of the machining corner that converts the feed rate of the tool, based on the data that approximates the fluctuation of the load applied to the tool cutting edge in the machining path of the work corner, the load changes abruptly from this approximated data. A plurality of shift point data whose points are shift points of the feed speed, a distance coefficient which is a coefficient of ratio distribution between the positions of the shift points and the machining path, and a start point at the shift points. From a starting point and a machining end point from the machining program at the time of actual machining, the storage means stores a feed rate coefficient which is a coefficient of a ratio distribution of the speed change to the change amount of the feed rate from the end point. A shift position point determining means for calculating a machining path, setting a plurality of intermediate position points of the actual shift point on the basis of the tool cutting edge radius and the distance coefficient at the shift point, and setting a plurality of points for the actual machining. The change amount of the feed speed at the start point and the feed speed at the end point is obtained from the machining program, and the actual intermediate feed rate at the intermediate position point is calculated based on the feed rate coefficient at the shift point with respect to the change amount of the feed rate. And a feed rate selection means for calculating and instructing the feed rate conversion device for the machining corner portion.