JPH0620718B2 - Feed rate conversion device for processing entrance - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a feed rate conversion device for a tool blade edge at a machining entrance for a work, and particularly to machining in which an intermediate speed is changed stepwise in response to a load change. The present invention relates to a feed rate conversion device for an inlet.

[Conventional technology]

When machining with a milling cutter, end mill, etc., the machining start point is set in front of the workpiece by the machining program at the machining entrance, and the tool cutting edge is fast-forwarded up to the machining start point, and thereafter the machining feed speed is set. It is usually In such a case, only the rapid feed speed and the machining feed speed are designated in the machining program, and conventionally, the conversion is performed at the machining start point at once.

[Problems to be solved by the invention]

In the above-mentioned conventional method, the load of the tool edge is not 100% efficient of the machining work and is varied until the tool edge is embedded in the workpiece by the radius, and the feed rate may be reduced to the feed rate during machining. Work time is delayed and inefficient. On the other hand, if the details of the feed rate are instructed, the number of languages of the program increases too much, which is still inefficient.

The present invention was devised in view of such problems, improves the quality of the finished surface by imparting the optimum cutting conditions corresponding to the load fluctuation at the start of cutting to the tool cutting edge, and improves work efficiency. It is an object of the present invention to provide a feed rate conversion device for a machining entrance portion that improves the machining efficiency.

[Means for solving problems]

In the present invention, as a means for solving the above-mentioned problems, as shown in the basic configuration in FIG. 1, there is a predetermined machining feed speed from a rapid feed speed up to a machining start point for a work set by a machining program. In the feed rate conversion device of the machining entrance that converts the feed rate of the tool edge to, the conversion position point setting that sets the intermediate position point of the feed rate conversion in the path from the machining start point to the point where the tool edge enters the workpiece The feed rate converter for the machining entrance is provided with means 1 and feed rate selection means 2 for instructing different intermediate feed rates for each of the sections divided by the intermediate position points. The machining program is stored in the machining program memory 3, and the data relating to the machining entrance and the tool edge data therein are stored in the entrance 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 tip T contacts the work W to a position P5 where the tool tip radius D reaches the work W and ends. The feed speed selection means 2 commands the intermediate feed speeds F1 to F5 which are different for each section divided by the intermediate position points P1 to P5 in correspondence with the current position of the tool edge. Gear shift position determination means 1
As shown in FIG. 1, the coordinate value of each intermediate position point determined by is once registered in the intermediate position point register 5 and then used in the feed speed selecting means 2 and the tool edge position detecting means 6 of the tool. It is detected by and is used by the feed speed selection 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 conversion position point determination means 1 for setting an intermediate position point of the feed speed conversion in the path of the 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 program, a machining program memory 3 for storing a machining program, and an inlet section for storing each data including a distance from a machining start point to a work contact point and a tool cutting edge radius for each step of the machining program. Data memory 4
An intermediate position point register 5 for registering the coordinate value of each intermediate position point determined by the 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. It is roughly configured by a CPU 7 that also functions as a control unit and controls each of the above means, a display 8 with a keyboard, and an entrance / exit port 9 thereof.

In this embodiment, since each data is processed by biaxial coordinates of X 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. Instead, the small calculation unit 10 is provided in front of the gear shift position point determination means 1, and the machining start point Ps set in the machining program is set.
From the coordinate values of (Xs, Ys) and the machining end point Pe (Xe, Ye), 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 edge has begun to enter the work, so as shown in FIG. 2, the rapid feed rate is not always set in the section from the machining start point Ps set in the machining program to the work surface. No need to slow down. Therefore, the first speed change point P1 is used as a contact point with the work surface, and the distance H from the machining start point Ps to the speed change point P1 and the cutting edge radius D of the tool are registered in the inlet data memory 4 for each program. In the shift position point determining means 1, the first
The calculation circuit 11 calculates the coordinate values X1 and Y1 of the first shift point P1 as X1 = Xs + H * cosα Y1 = Ys + H * sinα.

The second to fourth speed change points P2 to P4 are the second to fourth arithmetic circuits 12 to 14 in the speed change position point determining means 1 with the first speed change point P1 as the starting point and the tool tip radius D. Is determined by the following equation: Xi = X1 + D * cosα * Ki (i = 2 to 4) Yi = Y1 + D * sinα * Ki (i = 2 to 4) Fig. 4 is a characteristic diagram of load variation, which is a variation curve that approximates the variation of the load applied to the tool edge. The distance coefficient at the point (shift point) on the machining width where the load changes abruptly It is set as the distance coefficient Ki (i = 2 to 4) of each shift point in the example. That is, K2 = 0.1
5, K3 = 0.4 and K4 = 0.8 are set. Fifth shift point P
5 may be either the value calculated as K5 = 1.0 or the machining end point Pe of the program portion thereof.

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 the machining start point Ps of the inlet portion is obtained. When approaching, the speed conversion of this embodiment is executed. The real-time coordinate values Xi 'and Yi' of the cutting edge are input to the feed speed selecting means 2, and the comparison circuits 21 to 25 in the feed speed selecting means 2 are in which section the cutting edge position is with respect to the shift position point. To judge. For each section, the load speed characteristic which is the coefficient of the ratio distribution of the speed change with respect to the change amount of the feed speed from the start point to the end point at the shift point is used by using the load fluctuation characteristic diagram of FIG. Set. That is, the intermediate feed speeds F1 to F5 obtained by multiplying the machining feed speed Fe by the respective counts are set as shown in FIG. 2, and the intermediate feed speeds F1, F2, F3, F4 corresponding to the comparison circuits 21 to 25 are set. , Or F5. The fifth intermediate feed speed F5 is naturally the processing feed speed Fe.

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 entrance, it is automatically converted to the set intermediate feed speed, and machining feed corresponding to load fluctuations can be carried out.

〔The invention's effect〕

As described above, according to the present invention, by applying the optimum cutting conditions corresponding to the load fluctuation at the start of processing to the tool cutting edge, the working efficiency is improved and the quality of the finished surface is improved. It is possible to provide a feed rate conversion device for the inlet portion.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is an explanatory diagram of a processing inlet portion, FIG. 3 is a configuration of one embodiment of the present invention, FIG. 4 is a load fluctuation characteristic diagram, and FIG. Is a flowchart of the speed selection operation. DESCRIPTION OF SYMBOLS 1; Gear position position determining means, 2; Feed rate selecting means, 3; Machining program memory, 4; Inlet 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. A machining program in which a machining start point of a tool for starting a tool cutting speed at the entrance machining of a work at an initial feed rate, an end point for ending the approach to the work, and a tool cutting edge radius are input, Based on this machining program, in the feed rate conversion device of the machining entry part that converts the feed rate of the tool edge from the rapid feed rate to the machining start point to the specified machining feed rate, the tool edge in the machining path of the entry part of the workpiece On the basis of the data obtained by approximating the fluctuation of the load, a plurality of shift point data in which a point at which the load suddenly fluctuates from the approximated data is the shift point of the feed speed, and the position of this shift point and the machining path A distance coefficient, which is a coefficient of ratio distribution, and a feed rate coefficient, which is a coefficient of rate distribution of speed change with respect to the amount of change in feed speed from the start point to the end point at the shift point, are stored. The storage means and the machining path from the machining start point and the end point from the machining program during the actual machining are calculated, and the actual shift point is calculated based on the tool cutting edge radius and the distance coefficient at the shift point for this machining path. Shift position point determining means for calculating and setting a plurality of intermediate position points, and a change amount of the feed speed at the start point and the feed speed at the end point from the machining program during actual machining, and the change in the feed speed. And a feed rate selecting means for calculating and instructing an actual intermediate feed rate at the intermediate position point based on a feed rate coefficient at the shift point with respect to the amount. .