JPS598841B2 - How to create NC data for mold processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for creating NC data for mold machining using a copying machine.

In general, the following items are related to model copying accuracy by a copying machine.

Errors caused by stylus displacement Errors caused by thermal deformation of the copying machine Errors caused by the rigidity of the copying machine For these reasons, it is difficult to digitize the model shape using only information from the copying axis movement amount during copying. The accuracy was poor and there was no benefit.

Therefore, this invention attaches a digital scale to each moving axis of the copying machine to accurately measure the axis movement during copying, and at the same time measures each displacement of the stylus in three-dimensional directions and makes corrections. By eliminating errors due to displacement and performing copying at high speed without any load, errors due to thermal deformation and rigidity of the copying machine are eliminated, and extremely accurate NC data is created. be.

Furthermore, when actually performing NC machining, a tool diameter that is slightly different from the stylus diameter at the time of data creation may be used.

In that case, if the NC data is used to enable the use of the cutter offset function, more accurate machining will be possible.
For this purpose, this invention uses stylus center trajectory data as
An offset is made in advance in a direction corresponding to each pattern by the diameter of the stylus, and the offset function is inserted at the beginning of the NC data.

Hereinafter, specific examples of the present invention will be described with reference to the drawings.

Fig. 1 is a diagram showing a machining method using a normal copying model, in which a copying device A is attached to the spindle head C of a processing machine B, and a copying device A is attached to a spindle head C of a processing machine B, and a copying device A is controlled via a control device F by a signal from a stylus E that copies a model D. This shows a state in which simultaneous machining is performed by controlling and driving the drive devices G, H, and I for each axis.

In this case, since the stylus E is usually a contact type, it follows the model D with a certain displacement as shown in FIG.

On the other hand, the tool J cuts the workpiece K with almost no displacement.

Therefore, the shape machined by the tool J is the same as the stylus E.
The shape differs from model D by the amount of displacement. The displacement of the stylus E changes depending on the feed rate, the shape of the model D, etc., so in order to perform accurate machining by copying, a hot wire is required and various techniques are used.
The accuracy of copying has been improved to the current level.

In order to further improve accuracy, it is necessary to detect and control the model shape with almost no displacement, which is extremely difficult and expensive, and there are limits to its accuracy. .

In this invention, when tracing a model D with a stylus E, the amount of movement of each axis is detected without causing the tool J to cut the workpiece K, and the displacement of the stylus E at this time is separately taken out. By correcting the movement amount of each axis by that amount, accuracy can be improved easily and at low cost. FIG. 3 is a configuration diagram of this invention,
It is a conventional copying machine 1 with the addition of a detector 2 that directly detects the amount of movement of each axis of the machine, a detector 3 that detects the displacement of the stylus in three-dimensional directions, and a converter 4 that has a built-in computer. , the conventional copying machine 1 is made to copy at high speed with no load, and the amount of movement of each axis of the machine at that time is inputted into the converter 4 as a digital amount at every fixed cycle via the detector 2, and at the same time, the stylus 3 The dimensional displacement is captured by the detector 3 and corrected.

The above-mentioned stylus displacement correction is performed in the following manner.

FIG. 4 shows the displacement of an ordinary stylus. In this way, the stylus is displaced three-dimensionally, and is controlled so that ε in the following equation is constant.

On the other hand, there are few ordinary NC devices that have three simultaneous axes.
There are many cases where two axes can be used at the same time.

In order to provide versatility, the three-dimensional displacement is shifted on a plane tangent to the curved surface and converted into data for two axes at the same time. Figure 5 shows the displacement in the three-dimensional direction during contour tracing, vector ε
It is cut by a plane determined by XY and vector εz.

In this figure, R8 is the stylus radius, R is the tool radius, 08
is the center of the stylus, 0t is the center of the tool, 0h is the center of the stylus head, T8 is the contact point between the stylus and the model, T
1 is the contact point between the tool and the model.

At this time, the position obtained from the amount of movement of each axis of the copying machine is 0h
These are the coordinate values Xp, Y, ,Z, corresponding to the position of .

However, in the case of contour tracing, the angle range of β shown in FIG. 4 is from 00 to 87, and from 93rd to 180th.

By making this correction, it is theoretically possible to cut the shape of the model without error using tools with different diameters. Next time, when cutting is needed, when the planned tool is not available, a slightly different tool diameter Rt5 can be used to accurately cut, using the simultaneous two-axis cutter offset function that normal NC equipment has. The model contact point is offset to 00 in the diagram and converted into NC command data so that it can be used.

That is, FIG. 6 explains the X-Z surface tracing.

The meanings of the symbols are almost the same as in Figure 4. That is, if EX, e, , e2 are unit vectors in the orthogonal coordinate system, the unit vector noise is as follows.

The plane equation for the distance ε from the stylus center perpendicular to this vector is.

If the Y-axis is constant on this plane, that is, Y = 0 at the intersection with the vector ε ].

In order to perform the above-described correction of the stylus diameter R8 and the tool diameter R, they must be inputted in advance to the converter 4 shown in FIG. 3 as input data 5.

That is, the stylus diameter R8 and the tool diameter Rt are given to the data obtained by correcting the movement amount of each axis of the copying machine using the stylus displacement, and the data is corrected.

To create the NC data, interpolation accuracy, remaining stock, material shape, model pattern, etc. are input as input data 5 to create NC data corresponding to each process. The NC data is recorded on a floppy disk sheet with a large memory capacity, and the NC data is used to perform the NC processing using the copying machine.

By recording it on a floppy disk sheet, the NC data for each model can be stored for a long time, and furthermore, this data can be used to copy NC tapes for other NC machines using a puncher. In addition, even when applying to tools with different diameters, since a cutter offset function is provided, the NC data can be corrected and applied in the manner described above. As explained above, this invention adds a movement amount detector for each axis in a tracing manner, and also provides a three-dimensional displacement detector for the stylus, and uses a data processing method to calculate the shape of the mold model in the computer. It is equipped with a function to classify into several patterns and create NC data according to each pattern, and the finished model shape for the mold is placed on a copying machine and copied without any load, and each axis of the copying machine during copying is The amount of movement of the stylus and each displacement signal in three-dimensional directions of the profiling stylus are digitized and input into a computer at regular intervals, and the data is analyzed according to each pattern to eliminate shape profiling errors caused by stylus displacement specific to profiling processing. Since NC data for mold machining with high accuracy is created through correction, errors caused by stylus displacement, thermal deformation of the copying machine, and rigidity in conventional copying machining are eliminated, resulting in high-precision mold machining. It is possible to perform mold processing,
In particular, compared to the conventional method of creating NC data using automatic programming or using a three-dimensional measuring device, it is possible for on-site workers to easily create NC data at a lower cost.

Further, the present invention is very useful because it allows a two-dimensional cutter offset function, which is a normal NC function, to be used by providing a stylus diameter and a tool diameter.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional copying method, Fig. 2 is an explanatory diagram showing a state in which a stylus is copying a model, Fig. 3 is a block diagram showing the main structure of the present invention, and Fig. 4 is a diagram showing a stylus copying a model. Explanatory diagram showing the displacement in the three-dimensional direction in , No. 5
6 and 6 are explanatory diagrams of the principle for correcting NC data into two-dimensional force offset data in the present invention.

Claims (1)

[Claims] 1. A copying machine is equipped with a movement amount detector for each axis and a three-dimensional displacement detector for a stylus, and a computer stores a number of mold model shapes using a data processing method. The machine is equipped with a function to classify the finished model shape into individual patterns and create NC data according to each pattern. The movement amount and each displacement signal in the three-dimensional direction of the profiling stylus are digitized and input into a computer at regular cycles, and by analyzing the data according to each pattern, the shape profiling error caused by the stylus displacement specific to profiling processing is calculated by the computer. N for mold machining with automatic internal correction and high precision
A method for creating NC data for mold processing, characterized by creating C data. 2 In addition to adding a travel amount detector for each axis to the copying machine, a three-dimensional displacement detector for the stylus is also installed, and the computer classifies the mold model shape into several patterns using a data processing method. The machine is equipped with a function to create NC data according to each pattern, and the finished model shape for the mold is copied by the copying machine without any load, and the amount of movement of each axis of the copying machine during copying and the amount of movement of the copying stylus are recorded. Each displacement signal in the three-dimensional direction is digitized and input into the computer at fixed cycles, and by analyzing the data according to each pattern, the computer automatically corrects shape copying errors caused by stylus displacement specific to copying processing. N for precision mold machining
Create C data and apply it to this NC data for mold processing.
By inputting the diameter of the stylus to be used in advance into the computer, the above NC data is automatically corrected within the computer by the diameter of the stylus to be used, and the normal N.
A method for creating NC data for mold machining, characterized in that the NC data can be modified to be usable with a two-dimensional cutter offset function, which is a C function. 3 In addition to adding a travel amount detector for each axis to the copying machine, a three-dimensional displacement detector for the stylus is also installed, and the mold model shape is classified into several patterns in the computer using a data processing method. The machine is equipped with a function to create NC data according to each pattern, and the finished model shape for the mold is copied by the copying machine without any load, and the amount of movement of each axis of the copying machine during copying and the amount of movement of the copying stylus are recorded. Each displacement signal in the three-dimensional direction is digitized and input into the computer at fixed cycles, and by analyzing the data according to each pattern, the computer automatically corrects shape copying errors caused by stylus displacement specific to copying processing. N for precision mold machining
Create C data and apply it to this NC data for mold processing.
By inputting the diameter of the tool to be used in advance into the computer, the above NC data is automatically corrected within the computer by the diameter of the tool to be used, and furthermore, by making it possible to correct for other tool diameters, N for mold machining, which is characterized by being able to modify the NC data so that it can use the two-dimensional cutter offset function, which is the NC function of
C data creation method.