JPS63229248A - Nc machining data forming method - Google Patents

Abstract

PURPOSE:To form a data having both accuracy and efficiency by judging a load condition at the time of machining by means of a tool track, based on a tool track data in a three dimensional space and a three dimensional coordinate data for specifying the surface of a workpiece. CONSTITUTION:Plural cutter tracks for obtaining a prescribed shape are prepared and kept as a track file on an NC device side. And, an NC data forming program operates an actual cutter track, the advancing direction vector of a cutter, etc., and calculates the angle of the advancing direction vector. Further, the angles of the face vector and advancing direction vector for each point on the cutter track are obtained. And, in accordance with the larger one of the obtained angles, the feeding speed and rotating speed of a cutter is determined from a feeding speed/rotating speed file, to form an NC machining file. Thereby, a data having both machining accuracy and machining efficiency can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of creating data for NC machining, and particularly to a method of creating data for NC machining in consideration of machining load conditions for a machining tool.

(Prior Art) When machining a workpiece such as a mold, it is desirable to take machining load conditions into consideration. In particular, N.C.
When performing machining, it is necessary to consider the machining load conditions, broadly speaking, machining conditions. However, for example, JP-A-60-1
In No. 35162 etc., N is calculated from the three-dimensional shape of the model.
It merely creates data for C processing.

(Problem to be Solved by the Invention) Therefore, for a workpiece having a sloped portion as shown in FIG. Ta. For this reason, the horizontal portion, which can be machined at a higher speed than originally, is also machined at the machining speed of the slope, resulting in a low overall machining efficiency. On the other hand, increasing the machining speed comes at the expense of machining accuracy.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to achieve a N
The purpose of this paper is to propose a method for creating data for NC machining that allows C machining.

(Means and effects for solving the problem) The structure of the method for creating NC machining data of the present invention to achieve the above-mentioned problem is that the machining speed is determined according to the machining load conditions of the tool. Set the data in multiple ways in advance,
Based on the tool trajectory data in three-dimensional space and the three-dimensional coordinate data that defines the surface of the workpiece, determine the machining load conditions of the tool when machining the workpiece with the tool trajectory, and The present invention is characterized in that the machining speed data is selected according to machining load conditions, and the selected machining speed data is added to the tool trajectory data according to the machining instruction order.

(Examples) Examples according to the present invention will be described below with reference to the accompanying drawings. First, using FIGS. 1 and 2, we will explain how the NC data creation method of the embodiment is based on what elements.
Explain how to create data.

In Figure 2, the cutter 2 moves from point PI to point P2,
A state in which a workpiece 1 is cut is shown.

Here, it is assumed that the workpiece 1 has a slope 3, the angle of the slope 3 is α degrees with respect to the horizontal surface of the workpiece 1, and the horizontal surface 4 and the slope 3 have an intersection line 5. For convenience of explanation, the coordinate axes are such that the Y axis is superimposed on this intersection line 5, the X axis is on the horizontal plane 4, and the Z axis is on the top of the paper.

When the cutter 2 takes a trajectory as shown in FIG. 2, the load conditions of the cutter 2 during cutting are determined by the relative inclination of the machined surface with respect to the cutting direction. That is, this relative slope has two elements. One is the advancing direction of the cutter 2, and the other is the inclination of the machined surface. That is, even if the direction of movement of the cutter 2 is horizontal, if the slope of the workpiece 1 is large, this places a large load on the cutter 2. Similarly, even if the workpiece 1 is a horizontal plane, if the direction of movement of the cutter 2 changes significantly with respect to this plane,
The load on the cutter 2 is correspondingly large. Therefore, in this example, the load condition is not only the inclination of the machined surface, but also
Focusing on the fact that it must be determined by taking into account the direction of movement of the cutter 2 and the inclination of the machined surface with respect to the direction of movement, and considering both the direction of movement and the inclination of the cutting surface,
The degree of load during cutting is determined based on the larger slope.

Now, with reference to FIG. 1 below, the terms ``inclination in the traveling direction'' and ``inclination of the cutting surface'' mentioned above will be defined, and furthermore, how to determine the load conditions will be explained.

In Fig. 1, the inclination of the cutting surface is the angle (
θ, ). Here, point M is a point on slope 3, and point R is the intersection of line segment P2M and the XY plane. Therefore, the angle θ2 between the vector P2M and the XY plane is
The intersection line OR of the plane containing the vector P2M and perpendicular to the XY plane and the XY plane forms an angle with the line segment P2R. θ2
is an amount that does not depend on the direction in which the cutter 2 moves.

In addition, the inclination of the traveling direction is defined as the intersection of line segment QP2 and a plane that includes line segment QP2 and is perpendicular to the It can be defined as the angle θl formed with the line QO. This θ1 is a quantity that depends only on the traveling direction and does not depend on the shape of the workpiece 1.

The load condition is determined based on the larger angle, since the condition becomes worse regardless of which of the angles θ and 02 becomes larger. In the embodiments described below, cutter feed speed and cutter rotation speed are used as elements that must be able to reflect the load during machining.

Figure 3 shows the cutter feed rate (mm7 minutes) or cutter rotational speed (R
PM), when the diameter of the cutter is changed variously (
6φ to 40φ), respectively. As can be easily seen from the figure, the larger the inclination angle θ (the larger angle between θ1 and 02), the slower both the feed speed and rotation speed are.

FIG. 4 shows an outline of the procedure for creating such NC data. FIG. 5 shows the relationship between input/output files of the NC data creation program to which the data creation method according to the present embodiment is applied.

In a host computer system (not shown), a three-dimensional coordinate data file (master drawing data file) of the model is registered in a magnetic disk or the like based on product drawings, process drawings, cutter drawings, etc. Furthermore, a surface perpendicular vector (normal vector) is also created as a file from these wind mouth data through internal processing.

On the NC device side, the above-mentioned parent diagram data file and surface orientation vector file are received via a communication line or the like. Additionally, a plurality of cutter trajectories for obtaining a predetermined shape are prepared and saved as a trajectory file. The actual machining instruction program is expressed as the order of these locus definitions. The NC data creation program calculates the actual cutter trajectory from these trajectories,
Then, the moving direction vector of the cutter is calculated, and the angle between this moving direction vector and the XY plane is calculated.

Furthermore, for each point on the cutter locus, the angles that the plane perpendicular vector and the traveling direction vector make with the XY plane are determined. Then, according to the larger angle, the feed speed and rotation speed of the cutter are determined from the feed speed/rotation speed file as shown in FIG. 3, for example, and an NC machining file is created.

Then, final NC data is created from this NC processing file. That is, in addition to the conventional NC data, this final NC data includes data such as feed speed/rotation speed that has been appropriately changed in consideration of the load conditions on the cutter.

The above feed speed/rotational speed file is created so that the feed speed/rotational speed changes according to changes in the inclination angle θ and the cutter diameter, but the cutter neck coefficient and machining allowance coefficient are also changed. , and may be changed depending on the material of the workpiece.

Furthermore, since the cutting distance can be calculated using the cutter locus definition and machining instruction program, the cutter life can be estimated from this calculated cutting distance, and the cutter that seems to have reached its lifespan should be replaced. As if giving instructions,
It can also be added to NC data.

(Effects of the Invention) As explained above, according to the method for creating NC machining data of the present invention, data is created based on tool trajectory data in three-dimensional space and three-dimensional coordinate data defining the surface of the workpiece. , determines the machining load conditions when machining the workpiece with the relevant tool trajectory, and selects the machining speed data of the machining tool according to the machining load conditions, thereby achieving NC machining that achieves both machining accuracy and machining efficiency. We were able to provide a method for creating data for NC machining that is possible.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams explaining how machining load conditions are determined in an example; Figure 3 is a diagram showing the relationship between tool feed rate/rotational speed with respect to the inclination of the cutting surface; Figure 4 , FIG. 5 is a schematic diagram of a system for creating NC data, and FIG. 6 is a diagram explaining a conventional example. In the figure, 1...Workpiece, 2...Cutter, 3...Slope, 4
... horizontal plane, 5 ... line of intersection, P, ... starting point of machining,
P2...This is the end point of processing.

Claims (3)

[Claims] (1) Multiple sets of machining speed data that determine the machining speed of the tool are set in advance according to the machining load conditions of the tool, and the tool trajectory data in three-dimensional space and the three-dimensional data that defines the surface of the workpiece are set in advance. Based on the original coordinate data, determine the machining load conditions of the tool when machining the workpiece with the tool trajectory, select the machining speed data according to the machining load conditions, and follow the machining instruction order. An NC characterized in that the selected machining speed data is added to the tool trajectory data.
How to create processing data. (2) The three-dimensional coordinate data that defines the surface of the workpiece is a perpendicular vector, and the angle formed by the advancing direction vector of the tool trajectory with respect to the plane formed by two of the three-dimensional coordinate axes, and the Creation of data for NC machining according to claim 1, characterized in that the machining load condition of the tool is determined according to the value of the larger angle between the angles formed by the surface perpendicular vectors. Method. (3) The processing tool is a rotary cutting tool, and the processing speed data is data regarding the rotational speed and feed rate of the rotary cutting tool.
How to create data for NC processing described in section.