JPH0760605A - Nc sentence preparation method - Google Patents

Abstract

PURPOSE:To facilitate NC sentence editing work, and improve accuracy by recognizing a completed shape of a work, setting work order after a multistage work shape is divided into respective work parts, calculating a work start position and a work finish position with every work order, and preparing an NC sentence based on them. CONSTITUTION:In the case of a three-stage work hole, this is divided into three work parts, and work part numbers to identify the respective work parts are set in the respective divided work parts so that a work having the smallest diameter has the smallest work part number. An offset quantity, an air cut quantity and a work depth when only a part of the respective work parts is going to be worked independently are set for respective work parts, and that in which order what work part is worked is determined from a kind of tool or work accuracy, work processing speed or the like. A distance from the work surface of the work part and distances from the work surfaces of the whole work parts are compared with each other, and a work start position is determined according to an offset quantity, an air cut quantity and a work depth in the work part nearest to the work surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an NC statement creating method for automatically creating an NC statement of an NC machine tool.

[0002]

2. Description of the Related Art In an NC machine tool, not only the operations of a machine tool that are manually performed by an operator are automated, but also it becomes possible to perform difficult machining by manual operation.
Recently, NC control is used in all kinds of machine tools.

In recent years, the NC sentence used in this NC machine tool is created from the completed shape of the work based on the design data.
When a programmer inputs basic data such as the shape and material of a work, the type of tool, etc., NC statements such as tool paths and cutting conditions are automatically created by computer processing. In addition, a method of automatically creating an NC statement directly from data on a CAD or CAM system at the time of design has also been tried without the intervention of a programmer.

As a conventional NC sentence creating method, for example, Japanese Unexamined Patent Publication No. 252003/1990 discloses N for two-stage drilling.
A method of creating a C sentence is disclosed. According to this method, in machining a two-stage drill hole as shown in FIG. 8, after the first-stage drill hole 50 having a large diameter is opened from the input machining shape data and machining condition data, the second stage having a small diameter is processed. When opening the second drill hole 51, fast-forward the second-stage drill to P2 near the bottom of the hole drilled by the first-stage drill N
This is a method of creating a C sentence.

[0005]

However, in such a conventional NC sentence creating method, consideration is given to the case of using a step tool capable of machining two or more steps at a time when making a multi-step hole. Not not.
In addition, it is not a creation method that is conscious of changing the processing order, and for example, in the above method, it can be used when drilling the smaller diameter drill hole first and then the larger one. There was a problem that it could not be done.

Therefore, in the present invention, even when a step tool is used as a tool for performing multi-step hole machining, etc.
It is an object of the present invention to provide an NC statement creation method capable of creating a C statement and capable of handling an arbitrarily set processing order or a modification of the processing order.

[0007]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned objects includes a step of inputting a completed shape of a work in a method of creating an NC statement for machining a work by an NC machine tool. A step of recognizing a processed part from the recognized completed shape of the workpiece, a step of calculating an offset amount, an air cut amount and a processing depth of each of the processed parts, and a step of determining a processing order for processing the processed part. And the machining start position in the cutting feed for each machining sequence, comparing the distance from the work surface of the machining site set in the machining sequence and the distance from the work surface of all machining sites, and the comparison result However, if there is no machining site closer to the work surface than the machining site in the machining sequence performed before the machining sequence, the machining site closest to the workpiece surface among all machining sites is the machining start position in the machining sequence. Further, when the comparison result shows that there is a processed portion closer to the work surface than the processed portion in the processing order performed before the processing order, the comparison is performed from the work surface most in the processing order before the processing order. A step of determining a machining start position in the machining order based on a machining site located one distance away from a machining site having a long distance, and the machining start position when a plurality of machining sites are set in the machining order. Is determined for each machining site that is set, and a machining start position where any of the plurality of machining start positions does not contact an unmachined machining site, and the machining site set for each machining sequence And a step of determining a processing end position based on the offset amount, the air cut amount, and the processing depth of the NC statement creating method.

[0008]

According to the present invention configured as described above, the machining portion for each machining unit is recognized from the completed shape of the workpiece, and the offset amount, the air cut amount, and the machining depth are calculated for each machining portion.

Next, the processing order for processing the processing portion is determined, and the processing start position and processing end position in the cutting feed for each processing order are obtained.

In order to obtain the machining start position in the cutting feed for each machining sequence, the distance from the work surface of the machining site set in the machining sequence and the distance from the work surface of all machining sites are compared, When the comparison result shows that there is no processing site closer to the work surface than the processing site in the processing order performed before the processing sequence, the offset amount and the air cut of the processing site closest to the work surface among all the processing sites. The machining start position in the machining sequence is determined based on the amount and the machining depth, and
When the comparison result shows that there is a processed portion closer to the work surface than the processed portion in the processing order performed before the processing order, the comparison is performed with respect to the processing portion at the farthest distance in the processing order before the processing order. Offset amount of the processing part at a long distance,
The processing start position in the processing sequence is determined based on the air cut amount and the processing depth.

Further, when a plurality of processing parts are set in one processing order, the processing start position is determined for each set processing part, and one of the plurality of processing start positions is unprocessed. Select a machining start position that does not touch the machining site. Then, the machining end position is determined based on the machining amount of the machining site for each machining sequence.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment to which the present invention is applied will be described below with reference to the accompanying drawings.

In this embodiment, as shown in FIG.
An example will be described in which an NC sentence is created when performing three-step hole machining.

To create an NC sentence according to the present invention, first, CA
The completed shape data of the work is input using the D data. The machining shape of the workpiece is recognized from the input data and the machining conditions are set. Machining conditions include recognition of machining position coordinates, division of machining areas, recognition of machining hole information for each divided machining area, setting of machining order, and calculation of machining start position and machining end position for each machining order. , These are put together and completed as an NC sentence.

In the coordinate recognition of the machining position on the work, the hole reference position is obtained from the recognized completed shape by locating which part on the work is to be machined. The hole reference position is NC
It is the drilling coordinate in the machine tool coordinate system, or the movement end position when the tool of the NC machine tool is moved to the machining position on the work, and is the center position of the multistage machining hole as shown in FIG.

As shown in FIG. 1, the division into processed parts is as follows.
In the case of a three-step processed hole, since it is formed by three holes having different diameters, it is divided into three processed parts.
Then, a processing portion number for identifying each processing portion is given to each of the divided processing portions. The machined part numbers are set in ascending order from the machined part farthest from the hole reference position. As a result, the one having the smallest diameter inevitably becomes the smallest processing site number. In the present embodiment, as shown in the drawing, the processing site number is the one that is farthest from the hole reference position and has the smallest diameter, followed by the processing site number and the processing site number in that order.

Further, as machining hole information, an offset amount, an air cut amount and a machining depth are set for each machining region when it is attempted to machine only each machining region part. Here, the offset amount is the distance and direction from the hole reference position to the actual cutting start position, and the air cut amount is the distance and direction from the cutting feed start position to the actual cutting start of the workpiece (actual cutting start position). Yes, the machining depth is the depth of the hole from the actual cutting start position.

After setting the processing hole information, the processing order is set. As the machining order, for example, as shown in FIG. 2, a plurality of machining orders can be considered depending on which machining site is machined. Therefore, depending on the kind of tool used, machining accuracy, machining speed, etc. It determines which processing part is processed in which order.

The machining start position and machining end position for each machining sequence are calculated based on the machining hole information and machining sequence set as described above. That is, the cutting feed start position and the end position of the tool in one machining process are obtained.

A specific method for calculating the cutting feed start position for each machining order is to compare the machining site number (referred to as A) set in the target machining sequence with all machining site numbers,
If there is no processing part number larger than the processing part number A in the processing order before the target processing order, the maximum value of all the processing part numbers is selected, and the offset amount and the air of the processing part of the processing part number are selected. Find the cut amount. In addition, when the machining site number set in the machining sequence before the target machining sequence has a machining site number larger than the machining site number A, the smallest machining site number (hereinafter referred to as C) is selected. Then, the offset amount and the air cut amount of the processed portion having the processed portion number C-1 are obtained.

When there is only one combination of the calculated offset amount and air cut amount, that is, when the step tool is not used, the machining start position is calculated from the calculated offset amount and air cut amount. The machining start position is a distance that has advanced from the hole reference position by the offset amount and has returned by the air cut amount (see FIG. 1).

When a step tool is used as a tool for machining, a plurality of machining site numbers are set in the target machining order. In this case, the machining start position is calculated in the target machining order first. The offset amount and the air cut amount for each of the plurality of set machining site numbers are obtained as described above. At this point, a combination of a plurality of offset amounts and air cut amounts is obtained. Then, the tool reference point of the step tool to be used is obtained from the set processing depth of the processing portion. For step tools, there are multiple tool reference points. Place the obtained tool reference point at the machining start position calculated from each offset amount and air cut amount, and when aligning one tool reference point with the machining start position of that part, place the other tool reference point The distance from the hole reference position when the position is taken in the negative direction with the hole reference position as 0 point, as shown in (1) below.
Expression, tool reference point ≧ machining start position (1) Select a combination.

This will be described with reference to the drawings. As shown in FIG. 3a, the tool reference point a of the portion to be machined on the machining site is aligned with the machining start position a of the machining site. Then, in the case shown in the figure, the tool reference point b for processing the processing portion is such that the tool reference point b <the processing start position b, and therefore the above formula (1) cannot be satisfied. Next, as shown in FIG. 3b, the tool reference point (b) of the portion where the processing portion is processed is aligned with the processing start position b of the processing portion. Then, in the case shown in the drawing, the tool reference point a for processing the processing portion is tool reference point a> processing start position a, and therefore the above equation (1) is satisfied, so that the processing start position for this combination, that is, In the illustrated case, the processing start position b is the processing start position in the processing sequence using this step tool.

The tool reference point can be calculated from the machining shape, as shown in FIG. 3C, and the offset reference amount of each of the plurality of machined parts set in the machining order is added to the machining depth. The distance is the tool reference point.

Next, the machining end position is calculated by advancing an offset amount from the hole reference position from the machining hole information of the smallest machining site number among the machining site numbers set in the machining order.
The portion further advanced by the machining depth is the machining end position.

From the cutting start position, the end position and the hole reference position for each machining order obtained as described above, the tool movement amount and the hole reference position for moving the tool from the tool origin to the hole reference position in the machine tool coordinate system. To the cutting start position, the amount of rapid feed for advancing the tool from the cutting start position to the cutting start position, the cutting feed amount for cutting from the cutting start position to the end position, etc. are obtained as numerical data, and an NC sentence is created.

Next, an apparatus configuration for carrying out the NC sentence creating method of the present invention will be described with reference to the block diagram shown in FIG.

This device has a completed shape / command interpreting unit 1
Interprets the completed shape data and commands input from the CAD data 20 and the keyboard 21,
The hole reference position in the machine tool coordinate system is obtained from the completed shape data and stored in the coordinate system information storage unit 5, and the tool path information from the machine tool coordinate system reference position (tool origin) to the hole reference position is stored in the tool path information. It is stored in the section 4. In addition, the completed shape is divided into each machining portion, a machining portion number is given, and numerical data such as an offset amount, an air cut amount, and a machining depth of the divided machining portion is stored in the machining hole numerical information storage unit 3. .

The machining order of each machining region is interpreted from the input command, and the machining sequence number and the machining region number set in the machining sequence number are stored in the machining sequence information storage unit 2. Further, the input of the cutting condition or the like is stored in the cutting condition information storage unit 6.

When an NC sentence creation instruction is input from the keyboard 21, the offset amount air cut amount candidate selection unit 7 displays the machining sequence number from the machining sequence information storage unit 2 and the machining region number set in the machining sequence number. Also, the offset amount and the air cut amount of each machining portion and the data of the machining depth are retrieved from the machining hole numerical information storage unit 3, and the offset amount and the air cut amount for determining the machining start position in each machining order. Select a candidate for. At this time, when the step tool is used, a combination of a plurality of offset amounts and air cut amounts is selected.

An optimum combination is determined by the offset amount air cut amount determination unit 8 from the selected plurality of combinations of the offset amount and the air cut amount, and the processing start position calculation unit 9 is based on this. The processing start position is calculated, and the processing end position calculation unit 10 calculates the processing end position.

An NC program is created by the NC program creating unit 11 from the calculated machining start position and machining end position for each machining sequence, tool path information, coordinate system information, and cutting condition information, and is stored in the NC program storage unit 12. Remembered. The status of the NC program being created is displayed on the CRT screen via the display control unit 23.

In FIG. 4, the symbols attached to the respective signal lines indicate data or signals passing through the route of the signal line, and a:
Input of information, b: NC program creation instruction, c: offset amount, air cut amount, hole reference position (coordinate value), d: machining sequence number, machining site number, e: machining depth, f: offset amount and air Candidates for combination of cut amount, g: combination of determined offset amount and air cut amount, h: offset amount, i: machining end position (coordinate value), j: machining start position (coordinate value), k: tool path information , L: coordinate system information,
m: cutting condition information, n: NC program information.

Next, the flow of NC program creation will be described with reference to the flow charts shown in FIGS. 5, 6 and 7.

First, when an NC program creation instruction is input, the machining sequence number D is cleared to 0 (S1) and 1 is added to D.
In addition (S2), a candidate for a combination of the offset amount and the air cut amount for calculating the machining start position is selected by the repeated operation (S3 to S7) for the machining portion set in the machining sequence of this machining sequence number. To do.

For this, all the processing site numbers larger than the processing site number A set in the target processing sequence number D are searched from among the processing site numbers less than the processing sequence number (S3). When there is a large processing part number (S4), the minimum value C is selected from the processing part number group larger than the processing part number A (S6), and the offset corresponding to the processing part number obtained by subtracting 1 from the minimum value C is selected. Amount and air cut amount are selected (S7).

If there is no processing site number larger than the processing site number A (S4), the offset amount and the air cut amount corresponding to the processing site having the maximum value of all the processing site numbers are selected (S5).

After the repeated operation is completed, if there are a plurality of combinations of the offset amount and the air cut amount (S
8) The sub-module described later is activated (S20), and in one case, the machining start position is calculated from the selected offset amount, air cut amount and hole reference position.

The operation of the sub-module (see FIG. 7) operates when a plurality of combinations of the offset amount and the air cut amount have been produced up to the above. First, all the processing parts designated by the target processing sequence number D are processed. A tool reference point is calculated from the offset amount, the air cut amount, the processing depth and the hole reference position (S21).

Next, the tool reference points corresponding to each machining start position, which is determined by the combination of the offset amount and the air cut amount, are arranged and viewed. Then, the combination of the offset amount and the air cut amount such that the tool reference point is located farther from the corresponding machining start position with respect to the hole reference position is excluded (S22).

Next, from the remaining combinations, the arrangement relationship is selected in which the tool reference point corresponding to the minimum machining site number is farther away from the hole reference position (S23). Then, the position of the selected tool reference point is set as the processing start point (24).

Next, the process proceeds to the operation of determining the machining end position (see FIG. 6), the minimum value of the machining site number set as the target machining sequence number is extracted (S10), and the offset corresponding to the extracted machining site number is extracted. A machining end position is obtained from the amount, the machining hole depth and the hole reference position (S11).

Next, an NC program in the target machining order is created from the machining start position, the machining end position and the set tool path (S12).

Finally, it is judged whether or not the creation of the NC program for all machining orders has been completed (S13). If not completed, the connector 2 returns to step 2 (S2) to repeat the above operation, and again. When the NC program creation for each machining order is completed, the NC program creation operation is ended.

As a result, an NC program for each machining order is created, and thereafter, by linking this, an NC statement of a machine tool for machining a workpiece is completed.

[0046]

As described above, according to the NC statement creating method of the present invention, the completed shape of the work is recognized, the multi-step machined shape is divided into each machined portion, the machining order is set, and the machining order is set. Since it was decided to calculate the appropriate machining start position and machining end position for each, and to create the NC statement based on this, even if the machining order that was once set was changed, the optimum machining start position and end time would be obtained each time. Since the position is known, the NC sentence editing work can be facilitated and the accuracy can be improved. Further, when the numerical data of the completed machining of the multi-stage machining is corrected by changing the machining conditions or the machining shape, the NC sentence can be automatically corrected each time.

Further, by using the setting of numerical data and data definition used in a design tool (for example, tooling design, CAD, CAM, etc.), design information and NC can be obtained.
Since the relation with the sentence can be obtained, it is possible to reduce the man-hour for creating the NC sentence.

[Brief description of drawings]

FIG. 1 is a cross-sectional view for explaining the shape of a three-step processed hole.

FIG. 2 is a diagram for explaining an example of setting a processing order in an embodiment according to the present invention.

FIG. 3 is a cross-sectional view illustrating a machining start position in a machining order using a step tool in an example according to the present invention.

FIG. 4 is a block diagram for explaining a configuration of an NC sentence creation device for executing an embodiment according to the present invention.

FIG. 5 is a flowchart illustrating an NC sentence creating operation according to an embodiment of the present invention.

FIG. 6 is a flowchart for explaining the NC sentence creating operation of the embodiment according to the present invention, which is a flowchart following FIG. 5;

FIG. 7 is a flow chart for explaining a sub-module of the NC sentence creating operation of the embodiment according to the present invention.

FIG. 8 is a diagram for explaining a conventional NC sentence creating method.

[Explanation of symbols]

1 ... Completed shape / command interpretation unit, 2 ... Machining order information storage unit, 3 ... Machining hole information storage unit,
4 ... Tool path information storage unit, 5 ... Coordinate system information storage unit,
6 ... Cutting condition information storage unit, 7 ... Offset amount air cut amount candidate selection unit, 8 ... Offset amount air cut amount determination unit, 9 ... Machining start position calculation unit,
10 ... Machining end position calculation unit, 11 ... NC program creation unit, 12 ... NC program storage unit,
20 ... CAD data.

Claims (1)

[Claims] 1. A method for creating an NC sentence for machining a work by an NC machine tool, the step of inputting a completed shape of the work, and the step of recognizing a machined part from the recognized completed shape of the work. A step of calculating an offset amount, an air cut amount, and a processing depth of each of the processing parts; a step of determining a processing order for processing the processing parts; and a processing start position in cutting feed for each processing order, The distances from the work surface of the machining parts set in the machining order are compared with the distances from the work surface of all the machining parts, and the comparison result indicates that the workpieces are processed from the machining part in the machining order performed before the machining order. If there is no machining site closer to the surface, the machining site closest to the workpiece surface among all machining sites is set as the machining start position in the machining sequence, and the comparison result is performed before the machining sequence. When there is a processed portion closer to the workpiece surface than the processed portion in the processing order, the processed portion located one distance away from the processed portion farthest from the workpiece surface in the processing order prior to the processing order is used. And a step of determining a machining start position in the machining order, and when a plurality of machining parts are set in the machining order, the machining start position is determined for each of the set machining parts, and a plurality of machining start positions are set. A step of selecting a machining start position in which any one of them does not come into contact with an unmachined machining site, and an offset amount of the machining site set for each machining sequence,
An NC statement creating method comprising: a step of deciding a processing end position based on an air cut amount and a processing depth.