JPH07105271A - Dimensional tolerance processor - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide an extremely versatile dimensional tolerance processing device capable of accurately and automatically performing dimensional tolerance processing in a short time according to a dimensional tolerance processing pattern. [Structure] Connection between all graphic elements in the intermediate CAD data, and means for calculating the number and the number of places where the upper and lower dimensional tolerances are offset to either side in the intermediate CAD data Figure NO. , A means for constructing connection information such as a figure type and a connection part, and a dimension tolerance processing means for automatically correcting the intermediate CAD data in accordance with a designated dimension tolerance processing pattern to create another new intermediate CAD data. Accurate dimensional tolerance processing in time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimensional tolerance processing apparatus that supports a process of creating NC data for controlling the operation of an NC machine tool by using a CAD device and a CAM device.

[0002]

2. Description of the Related Art Generally, the flow of steps up to creating NC data for machining a product by an NC machine tool using different types of CAD devices and CAM devices is as shown in FIG. That is, in the first step, the product shape and, for example, the length dimension are determined by CAD.

[0003]

[Equation 1]

On the CAD, a drawing including a dimensional tolerance display in which the upper dimensional tolerance (+0.2) and the lower dimensional tolerance (-0.1) deviate to either the + side or the-side as shown in FIG. Make with. IGES (Initial Graphics Exchange Specification) which is an international standard for CAD data such as points, straight lines, arcs, curves, and dimension displays of drawings mechanically using software that is standard equipment of any CAD / CAM maker.
), DXF (Data Exc-hange Format), etc., according to the standard format, CAD data (this is called intermediate CAD data) is created. IGES in the world
Is most popular, the intermediate CAD data follows it.

In the second step, any CAD / CAM maker mechanically reproduces the same drawing as the original drawing from the intermediate CAD data by using software that is standardly equipped. In the third step, based on the reproduced drawings,
If at least one of the upper / lower dimensional tolerances such as length, radius, diameter, angle, etc. deviates to either the + side or the-side, consider the machining error (± μ) of the NC machine tool. Then, a person works on the CAD or the CAM so that the dimensional tolerance becomes even on the + side and the-side (this is called dimensional tolerance intermediate value processing). In the fourth step, a step of creating processing data (NC data) for controlling the operation of the NC processing machine on the basis of the drawing subjected to the dimensional tolerance intermediate value processing is performed. If the CAD device and the CAM device are machines of the same model, the second step is not necessary. Here, the dimensional tolerance intermediate value process of the third step is as follows in the example of the length dimension.

[0006]

[Equation 2]

Depending on the characteristics of the product, the dimensional tolerance intermediate value process may not be performed. Such dimensional tolerance processing is carried out in order to increase the probability that the originally machined product can be machined within the range of the minimum permissible dimension to the maximum permissible dimension when machining a product with an NC machine tool. What is important is that it is necessary to maintain the connected state with the figures such as straight lines and arcs corrected by the dimensional tolerance processing described above and all figures that were connected before the correction.

[0008]

The dimensional tolerance intermediate value processing in the third step can be reliably performed with a small amount of labor in a few places because a person works. However, as the number increases to 10, 20, ..., this kind of work is very troublesome and takes a long time. become. Such poor work efficiency,
Inevitably has the issue of reliability issues. Also,
The dimension tolerance processing method used in the commercially available CAD / CAM system depends on the model of the machine provided by the manufacturer, cannot be used in another model, and has a major problem to be solved in practice, which is not versatile. (JP-A-4-175
No. 978).

That is, the CAD / CAM system includes a shape defining means defined from at least three views including dimensions of a product shape, and a shape storing means for storing each data of the shape and the dimension in the defined drawing. It is defined by the dimension expansion means between drawings that supplements the dimension of the drawing that is not previously defined from the stored dimension data of the drawing, and the dimension including the calculated intermediate tolerance value by calculating the intermediate tolerance dimension from these nominal dimensions with tolerances. And an automatic tolerance dimension / shape automatic generation means for creating a drawing. Such a CAD / CAM system requires the development of a program that directly accesses the drawing database unique to the CAD device, performs the dimensional tolerance intermediate value processing, and recreates the drawing database. Therefore, C
There is a problem that specialized knowledge is required regarding the AD database and the development program is not versatile.

The present invention is a dimensional tolerance processing device that solves the above problems. That is, the dimensional tolerance processing device of the present invention,
For example, the dimensional tolerance intermediate value process is realized without directly accessing the drawing database specific to the CAD / CAM device. It automatically reads the data that is offset to the dimensional tolerance described in the intermediate CAD data, corrects it to the intermediate value of the dimensional tolerance, and also corrects the graphic information closely related to it, and creates new intermediate CAD data.
Any CAD / CAM maker uses standard software to display the drawing with the intermediate dimension tolerance value processed on the CAD / CAM device based on the intermediate CAD data. It has excellent reliability and versatility. As described above, according to the present invention, the intermediate value processing is not performed on all or a part of the above-mentioned offset depending on the character of the product, or the intermediate value processing is not partially performed even if the offset is present. Accurate dimensional tolerance processing in a short time according to the dimensional tolerance processing pattern, such as setting the reference dimension to the minimum allowable dimension value, maximum allowable dimension value, or any value between the minimum allowable dimension value and the maximum allowable dimension value. It is an object of the present invention to provide a dimensional tolerance processing device that performs automatic processing and is highly versatile regardless of the machine model.

[0011]

SUMMARY OF THE INVENTION A dimension tolerance processing apparatus of the present invention mechanically transfers points of CAD data of a drawing including a product shape and dimensions from a CAD / CAM apparatus to a CAD / CAM apparatus and reproduces mechanical points, CAD of straight lines, arcs, curves, etc.
Means for calculating the location and the number of locations where the CAD data (hereinafter referred to as intermediate CAD data) created according to the standard format of the data has a dimensional tolerance such that the upper and lower dimensional tolerances are offset to either one. And the intermediate CAD
Graphic No. at the connection between all graphic elements in the data
A means for constructing connection information such as the type of figure and connection part, and the intermediate C automatically according to the specified dimension tolerance processing pattern.
Dimension tolerance processing means for correcting the AD data and creating another new intermediate CAD data.

[0012] Here, the means for calculating the place where the dimension is displayed and the number thereof are provided by the CAD / CAM device through CAD / C.
When transferring and reproducing the CAD data of the drawing including the product shape and dimensions to the AM device, mechanical software such as points, straight lines, arcs, and curves can be used to mechanically convert the CAD data of the software using commercially available software. Length, radius, and diameter such that the upper / lower dimensional tolerance in the intermediate CAD data created according to the international standard formats such as IGES and DXF deviates to either + side or-side. It is possible to calculate the place where the dimensional display such as the angle is displayed and the number thereof. Further, the means for constructing the connection information is connected to all the other graphic elements with respect to each graphic element including points, straight lines, arcs, curves, dimension displays, etc. of the graphic elements in the intermediate CAD data. It is possible to build inter-graphic connection information such as the type of graphic element, connection position, and tangential continuity. Further, the dimensional tolerance processing means has dimensional tolerances such as length, radius, diameter, angle, etc. such that the upper / lower dimensional tolerance in the intermediate CAD data deviates to either the + side or the-side. If it is detected that there is a display, the specified dimension tolerance processing pattern, the reference dimension value in the dimension tolerance display, the upper / lower dimension tolerance value, the reference dimension value, ± tolerance value or / Recalculate the dimensional tolerance value below and connect the figure elements corresponding to the figure element in the intermediate CAD data and the figure elements closely related to the figure element from the connection information between the figures without omission. Automatically change the intermediate CAD data to another new intermediate C so that it becomes a graphic element that maintains information and consistency.
Create AD data.

As described above, the present invention mechanically performs CA by using software which is generally commercially available based on the new intermediate CAD data generated by the dimension tolerance processing device.
The conventional problem can be solved by obtaining a drawing modified according to the dimensional tolerance processing pattern indicated on D. As described above, the present invention has a practical effect that is different from the conventional one in that the intermediate CAD data is recreated, and has a practical effect that can be applied to any type of CAD device and CAM device.

[0014]

The dimensional tolerance processing apparatus of the present invention can easily obtain a drawing corrected in accordance with the dimensional tolerance processing pattern designated by the above, and the dimensional tolerance processing which is conventionally performed by a person on CAD / CAM is complicated. Erroneous work becomes unnecessary, and the work time of the process of creating the NC data for controlling the operation of the NC machine tool can be greatly reduced and the reliability is improved.

[0015]

As described above, the dimensional tolerance processing apparatus of the present invention can easily obtain a drawing corrected in accordance with the designated dimensional tolerance processing pattern, and the dimensional tolerance processing that is conventionally performed by a person on CAD / CAM is complicated. The operation that is easy to make mistakes becomes unnecessary, and N for controlling the operation of NC machine tools
The working time of the process of creating C data can be greatly reduced and the reliability is improved. In addition, commercially available CAD
Some CAM systems have different methods from the dimensional tolerance intermediate value processing in the present invention, but this depends on the machine model provided by the manufacturer and is not versatile and cannot be used in another model. On the other hand, the dimensional tolerance processing device of the present invention is sufficiently versatile that it does not depend on the model of the CAD / CAM device at all and can be adapted and installed in any CAD / CAM device. Dimensional tolerance processing device.

[0016]

EXAMPLES The present invention will be described in detail based on the following examples. The present invention is not limited to the examples below. FIG. 1 is a block diagram of a dimensional tolerance processing device of this embodiment. FIG. 2 is a CAD drawing of an example before dimensional tolerance processing, in which all four deviations of the upper / lower dimensional tolerances are designated as the dimensional tolerance intermediate value processing in the dimensional tolerance processing pattern. FIG. 3 is an excerpt of the intermediate CAD data of FIG. 2 mechanically created according to the standard format of IGES using software that is standardly equipped by any CAD / CAM maker. As shown in FIG. 3, the format of this IGES data is composed of five sections: a start section, a global section, a directory section, a parameter section, and a termination section. A comment is placed in the start section and a data delimiter is placed in the global section. Intermediate CAD such as symbols
Information for reading the data, line type in the directory part,
Attribute information for each figure such as line width and color is described in two fields divided into 20 fields, and in the parameter section, each figure such as straight line, arc, dimension display etc. defined in the directory section is described. Specific geometric information such as the coordinate values of the start point, end point, and center point, and the total number of lines of data in each part are described in the terminated part. The number of lines of data in each part is described by the required number of lines. . In this embodiment, the information in the directory portion and the parameter portion is rewritten to create new intermediate CAD data. The method is divided into three phases as shown in FIG.
Each phase will be described below.

In Phase 1

[Table 1] The upper / lower dimensional tolerance is + side in the intermediate CAD data of
Calculate the location (graphic element No.) and the number n where the dimension display is offset to either side of the minus side. The calculation method is easy, and the presence or absence thereof can be determined by the numerical value of the fifteenth field of the element for displaying the dimension in the data of the directory portion of the intermediate CAD data. In this embodiment, the length dimension is 2 It can be seen that there are a total of n = 4 places (figure element Nos. 7 to 10 in FIG. 2), one for each place, one for the diameter and one for the radius. As a result, when there is the deviation (n ≠ 0), the process proceeds to phase 2. In Phase 2, check all data in the directory part and parameter part of the intermediate CAD data

[Table 2] As shown in Fig. 2, the parent / child figure No. at the connection point between each figure element (which is called a parent) and all other figure elements (which is called a child) in the example diagram of FIG. , The figure type, the connection part, the tangent continuity, and the like are connected to each other, and the process proceeds to phase 3.

In phase 3, the dimensional tolerance is calculated based on the figure element number corresponding to the dimensional tolerance process calculated in phase 1, the number n, the inter-graphic connection information in Table 2, the intermediate CAD data, and the designated dimensional tolerance processing pattern. To process. In this embodiment, all the patterns are processed as the dimensional tolerance intermediate value process. This dimensional tolerance processing means is provided with 2 as shown in FIG.
Processing is divided into two steps, and in step 1, four graphic elements corresponding to the dimension tolerance calculation calculated in phase 1
No. 7 to 10 are usually independent of other graphic elements

[0019]

[Equation 3]

Reference dimension value (X) expressed as
Lower dimensional tolerance value

[0021]

[Equation 4]

Is read from the data of the parameter portion of the intermediate CAD data, and new reference dimension value X'and ± tolerance value α are calculated according to the equation (1),

[0023]

[Equation 5]

For example, for graphic element No. 7, X = 4
0, a = + 0.04, b = 0 to X ′ = 40.02, α
= 0.02 and on CAD / CAM '40 .02 ±
The data of the parameter part of the intermediate CAD data including the dimension value, the dimension line, and the dimension extension line is rewritten as new intermediate CAD data so that it is displayed as 0.02 ', and at the same time, as shown in Table 2, the dimension of No. The coordinate values of the start and end points of the data in the parameter section of the intermediate CAD data are calculated by expanding and contracting the straight line of the child graphic element No. 1 corresponding to the display so that the length becomes X ', and as new intermediate CAD data. rewrite.

The same applies to the case of the radius dimension such as No. 9. At the stage where this step 1 is completed, the straight line and the arc (which is called parent), which have been subjected to the dimension tolerance processing independently, are generally divided into the straight line and the arc (which is called the child) which have been connected until now, and they are left as they are. Since it does not hold as a drawing, as shown in Table 2, the connection state of the child previously connected to the parent, the grandchild connected to the child, ... Must be completely restored, and this must be done in step 2 It is called the post-processing of the dimensional tolerance processing. In this embodiment, there are two cases of this post-processing, that is, the parent is a straight line (length dimension) and a circular arc (radius, diameter dimension), and they are treated separately. Parents are straight (No.
In 1 and 2), the figure type of child, grandchild, ... Is arc or
Is a straight line that is orthogonal to the parent straight line, the child, grandchild, ... (A + b)
Translate for a length of / 4. Repeat this for children, grandchildren, and so on. For the children, grandchildren, and so on, which are parallel to the parent line (this is the last straight line), use either the start point or end point coordinate value of that line. A new start point and end point coordinate values that are close to the start point and end point coordinate values of the next higher parent (grandchild if the child is a grandchild) are repeated as many times as the number of parent children, and the changed children and grandchildren The coordinate values of the straight line, ..., The starting point, the ending point, and the center point of the circular arc can be written as new intermediate CAD data. Then, in the case where the parent is an arc (No. 5, 6), as shown in Table 2, the parent arc (No. 5) is added to the child arc (No. 6).
Are connected, or vice versa, so it is not necessary to process both, and only the former process needs to be performed.
Since the processing of step 1 has been completed for both arcs, the coordinate value data of the start point, end point, and center point are updated to a new intermediate C
It is read from AD data, the parent arc and the child arc are considered as closed arcs, and the coordinate values of the intersection points of the two circles are calculated. A new intermediate point is created so that the intersection points become the coordinate values of the start point and end point of the parent arc and child arc. Rewrite the CAD data.

In addition to the present embodiment, for example, the parent arc is already subjected to the single dimension tolerance processing, and the parent arc is placed on the center point of another arc, contacts with one straight line, or 2
It may come into contact with a straight line, one straight line or one circular arc, or two other circular arcs, but this is also a simple geometric calculation, and the start point, end point, and center point of the parent / child The coordinate value of can be calculated.

Further, in addition to the present embodiment, for example, as shown in FIG. 6, the dimension is described in the figure immediately adjacent to the dimension corresponding to the dimension tolerance processing such as the length, radius, diameter, angle, or the center, There may be a case in which the same figure exists at symmetrical positions across the line and there is no description of dimensions. On the other hand, the dimensional tolerance processing device of the present invention can be sufficiently applied and implemented. That is, in the former case, one of the corresponding figures (reference numeral A in FIG. 6) is used as the other reference (reference numeral B in FIG. 6).
Is expanded or contracted, or the other is expanded or contracted based on A or B. In the latter case, the same processing as the former is performed at the same time.

[Table 3] As shown in FIG. 5, a symmetry relation table as the connection information between the graphic elements is created in advance, and the same processing is performed on the graphic having the symmetry relation.

Based on the new intermediate CAD data rewritten by the above-described procedure, any CAD / CAM maker mechanically uses CAD software to equip the CAD / CAM mechanically with respect to Table 1. All the dimensional tolerance intermediate values are processed to obtain the drawing shown in FIG. 5 with no deviation of the upper / lower dimensional tolerances. Further, although the present embodiment uses the two-dimensional CAD, the same processing can be performed in the three-dimensional CAD.

[Brief description of drawings]

FIG. 1 is a block diagram showing a dimensional tolerance processing device of the present invention.

[FIG. 2] FIG. 2 is an example diagram before dimensional tolerance processing is performed.

FIG. 3 is a format diagram of IGES data.

FIG. 4 is a block diagram of dimensional tolerance processing means.

FIG. 5 is a top / bottom view obtained mechanically using software that is standard equipment of any CAD maker based on the new intermediate CAD data after the dimensional tolerance processing with respect to FIG. 2. Drawing on CAD / CAM without dimensional tolerance

FIG. 6 is an example diagram showing another dimensional tolerance process.

[FIG. 7] FIG. 7 is a flow chart of a process for creating NC data for processing a product by an NC machine tool using a CAD device and a CAM device of different models.

[Explanation of symbols]

 1, 2, 3, 4, ... Graphic element (straight line) 5, 6 ..., Graphic element (arc) 7, 8, 9, 10 ... Graphic element (dimension display)

Claims (1)

[Claims] 1. A CAD / CAM device to CAD / CAM
When transferring and reproducing the CAD data of the drawing including the product shape and dimensions to the device, C which is mechanically made according to the standard format of CAD data such as points, straight lines, arcs and curves
Above / inside AD data (hereinafter referred to as intermediate CAD data)
A means for calculating the number of places and the number of the dimension indications where the lower dimension tolerances are offset to either one, and the figure No. and figure type in the connection portion between all the figure elements in the intermediate CAD data. , A means for constructing connection information such as a connection part, and a dimension tolerance processing means for automatically correcting the intermediate CAD data according to an instructed dimension tolerance processing pattern to create another new intermediate CAD data. Dimensional tolerance processing device.