JPH06246586A - Numerical control program preparing device - Google Patents

Abstract

PURPOSE:To provide a Z-direction approach system without the generation of a bite and the like. CONSTITUTION:A numerically controlled program preparing device is provided with a shape model data memory part 6 prepared from CAD data to store it, a machining data memory part 10 storing machining conditions and output conditions, a Z-approach preparing part 11 for assigning tool approach to the machined face, and a zigzag approach preparing part 31 prepared on the basis of the shape model, the machining data and assigned information from an approach condition assigning part 8. This device also has an NC data memory part 33 formed of the shape model, machining data, Z-direction approach and zigzag approach to store them so as to have the built-in zigzag direction approach in the Z-direction approach. Since zigzag approach is added in the Z-direction, the chipping of a cutting edge and a bite into a workpiece at the time of a tool coming in contact with the machined face is prevented to improve the approach to a recessed part and also to prolong the service life of the tool in large degree.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an NC program creating apparatus for creating a numerical control (NC) program for giving a command to a numerically controlled processing machine.

[0002]

2. Description of the Related Art In recent years, a general method is to create NC data on the basis of data such as drawings and CAD, and use this data to machine a workpiece such as a die using a cutting tool with an NC machine tool. It is becoming more common. As described above, NC data must be created in order to machine a workpiece with an NC machine tool. N to create this NC data
A C program creating device is used. That is, the NC program creation device forms a shape model of a workpiece from CAD data and the like, and the machining conditions such as cutting speed and output conditions,
Alternatively, the approach method is input to create NC data. Then, based on this NC data, for example, a processing material is processed by an NC machine tool using a cutting tool such as an end mill to form a desired product shape.

By the way, in such a machining process, there is a step in which the cutting tool is moved to approach the position where the machining of the shape is started. Although this is called an approach, this approach step is a step of moving the cutting tool from the start position to the shape processing start position via the cutting start point in the shape processing step for processing the workpiece into a desired shape, It does not directly affect the processed shape. It is well known that such an approach method includes a Z direction approach, a circular arc approach, and a normal direction approach. Among them, in the case of a shape having a working surface such that the tool has to descend directly onto the working surface, the Z-direction approach is used as the approach method.

A conventional technique will be described below with reference to the drawings. FIG. 5 is a system block diagram of an NC program creating device for forming a conventional Z-direction approach.

A medium such as the magnetic tape 1 contains various CAD information regarding drawings. Information from the magnetic tape 1 is input to the CAD data input section 2 as magnetic information.
This magnetic information is converted into shape data by the CAD data converter 3. The shape model creation unit 5 uses the tablet mouse 4 based on the conversion signal from the CAD data conversion unit 3.
Create a shape model of the product to be processed by specifying external information from input devices such as. The shape model of the product created by the shape model creation unit 5 is stored in the shape model data memory unit 6. From the keyboard 7, approach conditions such as clearance and finishing allowance can be specified in the approach condition specifying unit 8, and tool diameter, machining allowance, feed speed, rotation number, feed amount, output unit of the processing machine can be specified in the machining data specifying unit 9. Various cutting conditions and output conditions are input. Then, the processed data memory unit 10 stores various processing conditions and output conditions designated by the processed data designation unit 9. The Z-approach creating unit 11 forms Z-direction approach conditions based on the conditions of the approach condition designating unit 8 and processing data.

Next, in the NC data creating section 12, the die machining is performed based on the stored contents of the machining data in the shape model data memory section 6 and the machining data memory section 10 and the Z direction approach condition of the Z approach creating section 11. Create various data for NC required for. And this NC data is NC
It is stored and accumulated in the data memory unit 13. Each stored N
The C data is input to the output signal creating unit 14 which is a data output mechanism for outputting to the external device, and the display signal converting unit 1
It is displayed on the CRT 16 according to the display signal converted in 5, or stored in the floppy disk (hereinafter abbreviated as FD) 18 according to the storage signal converted by the storage signal converter 17.

FIG. 6 is a diagram of a shape model showing a conventional Z-direction approach. FIG. 6A is a perspective view showing the concept during machining.
(B) is a schematic diagram showing the details of the Z approach.

A surface 20 to be processed is formed by a ball end mill 21 on the mold 20 which is the object to be processed. The (B) diagram shows the Z approach method in this processing. d is the radius of the ball end mill 21, and e is the upper surface 23 of the mold 20.
To the finished surface 24, g is the clearance at the start of processing, and h is the finishing allowance. In the Z-direction approach at this time, first, the point A is set as a start point, and
Positioning in the Z direction is performed by rapid feed to the point B, which is the cutting start point, leaving the clearance g up to. Next, (e + g
While the processed surface is processed by the amount of −h), it is lowered straight to the point C which is the processing start point of the shape. After that, point C
The desired processing is performed in the direction from to arrow F. Finally, in the next step, the finishing allowance h up to the finishing surface 24 is cut to complete the processing.

FIG. 7 is a flowchart showing the operation of the NC program creating apparatus including the conventional Z-direction approach method. Below, referring to the shape model of FIG. 6, N of FIG.
The operation of the C program creating device will be described.

First, CAD data contained in a medium such as the magnetic tape 1 is input to the CAD data input section 2 (S
1) The CAD data converter 3 converts this data into shape data (S2). Based on the converted CAD data, the shape model creation unit 5 creates a model of the product shape by input from the tablet mouse 4 (S3). This shape model data is stored and saved in the shape model data memory unit 6 (S4). Next, the Z direction conditions such as the machining direction F, the clearance g, the finishing allowance h, and the Z approach feed speed are input by the approach condition designating unit 8 using the keyboard 7 (S5). At the same time, the machining data designating section 9 designates the machining conditions such as the type of the tool, the tool radius d, the machining allowance e, and the feed rate, using the keyboard 7 (S6). Then, the specified processing conditions and output conditions are stored and stored in the processing data memory unit 10 (S7). In addition, the Z approach creation unit 11 is based on the specified approach conditions and the like.
A Z-direction approach method is created by (S8).

Based on the shape model data determined as described above, the processing data such as the processing conditions and the output conditions, and the Z direction approach data, the NC data creation unit 12 creates the NC data. (S9), N
The data is stored in the C data memory unit 13 (S10). The NC data stored in this manner is output to the output signal creation unit 14. In the output signal creation unit 14, the display signal conversion unit 15
Can be converted into a display signal and displayed on the CRT 16 (S11), or can be converted into a magnetic signal by the storage signal conversion unit 17 and externally stored in the FD 18 (S12).

[0012]

As described above, according to the conventional NC program creating apparatus, in the machining of the shape having the machining surface such that the cutting tool has to descend directly to the machining surface, the Z direction approach is taken. Becomes However, in the case of a cutting tool having no cutting teeth near the center of the bottom such as a ball end mill or a flat end mill, there is a drawback that a phenomenon unfavorable to processing occurs such as cutting teeth chipping or biting. .

The present invention has been made to solve the above-mentioned problems, and incorporates an NC approach that does not cause biting when approaching in the Z direction.
An object is to provide a program creation device.

[0014]

In order to achieve the above-mentioned object, in the NC program creating apparatus according to the present invention, the cutting tool approaches from the position where the cutting is started to the shape processing start position where the shape is processed. When an approach condition designating unit that designates the calculation condition of the approach trajectory that is the trajectory to be used, and the cutting tool used by the approach condition designating unit is designated as an end mill, the approach trajectory is the component of the end mill rotation axis direction and this rotation. It has a zigzag approach trajectory calculating unit that calculates an approach trajectory so as to always have a component orthogonal to the axis.

[0015]

In the NC program creating apparatus of the present invention having the above-described structure, when approaching in the Z direction, it is not directly lowered directly, but an approach from an oblique direction including a lateral component (a zigzag approach) is also incorporated. Since the cutting is performed at 0, the cutting at the cutting speed of 0 is eliminated, so that it is possible to remove processing defects such as chipping of the cutting teeth and biting.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same components as those described in the related art are designated by the same reference numerals to simplify the description. Figure 1
FIG. 3 is a system block diagram showing an example of an NC program creating device using the configuration of the present invention.

In FIG. 1, the process is the same as that of the conventional technique up to the point that a Z approach creating unit 11 that forms an approach condition in the Z direction based on the designation condition of the approach condition designating unit 8 is provided. A feature of the present invention is that it has a Z approach creating unit 11 as an approach in the Z direction, and the designation from the approach condition designating unit 8 is made based on the stored data of the shape model data memory unit 6 and the machining data memory unit 10. The zigzag approach creating unit 31 for forming the zigzag approach condition is provided. Then, in addition to the stored data of the shape model data memory unit 6 and the machining data memory unit 10 and the Z direction approach condition of the Z approach creation unit 11, the zigzag approach created by the zigzag approach creation unit 31 is added to the NC data. NC required for NC processing by the creation unit 32
Create the data. Then, this NC data is stored in the NC data memory unit 33. It should be noted that each stored data is displayed on the CRT 16 or stored in the FD 18 via the output signal creation unit 14 as in the conventional technique.

FIG. 2 is a shape model diagram showing the Z-direction approach of the present invention. FIG. 2A is a perspective view showing the concept during machining.
(B) is a schematic diagram showing details of the approach.

The work surface 22 of the die 20, which is the work, is processed by the ball end mill 21. The approach method in the Z direction in this processing is shown in FIG.
As in the prior art, d is the radius, e is the stock removal, g is the clearance, and h is the finishing stock. Further, as a numerical value related to the zigzag approach, a is the ball end mill 21.
Is a shift amount in the direction orthogonal to the rotation axis, b is a downward shift amount in the rotation axis direction in the machining direction, and c is a downward shift amount in the rotation axis direction in a direction opposite to the machining direction. .
In the zigzag approach of the present embodiment, the Z direction is positioned by rapid feed from the start point A to the cutting start point B where the cutting process is started, leaving a clearance g. Then point B
From the point to point C, it is lowered diagonally downward in the F direction, which is the machining direction, and then from point C to point D, it is lowered diagonally downward in the opposite direction to the machining direction, and shape machining is started. It approaches to the position.

FIG. 3 is a flowchart showing the operation of the NC program creating apparatus shown in FIG. Next, an NC program creating device including a zigzag approach in the Z direction of the present invention will be described with reference to FIGS. 1 and 2.

First, the CA contained in a medium such as the magnetic tape 1
The D data is read by the CAD data input unit 2 (S2
1). The CAD data conversion unit 3 converts the CAD data into shape data for the NC program creating device (S22). Further, the shape model is created by the shape model creation unit 5 based on the shape data by the input device such as the tablet mouse 4 (S23). Next, the actual numerical values of the approach conditions such as the zigzag Z approach are discriminated, the machining direction F, the machining direction shift amount a, the clearance g, the finishing allowance h, and the approach feed speed are input to the approach condition designating unit 8 using the keyboard 7. Input (S24). At the same time, the numerical value of the machining condition such as the tool radius d, the type of the tool, for example, the distinction between the ball end mill and the flat end mill in the case of the end mill, the machining allowance e, the tolerance, the pick feed, the feed rate, etc. is input to the machining data designating section 9 by the keyboard 7. S25).

Next, as indicated by an arrow 31 in FIG. 2, the ball end mill 21 is left with a clearance g from the start point A to the cutting start point B, which is (e + g) above the machining finish surface 24, that is, to the die upper surface 23. It moves to the position immediately below by rapid traverse and positions in the Z direction (S26). Here, it is determined whether or not the Z approach is the zigzag approach (S27). If YES, the process proceeds to step S28. Step S28 is a zigzag approach and point B
From the point C to the point C, the XY direction is a shift amount a in the F direction to be processed, and the Z direction is a downward shift amount b
Only [= (e + g−h) / 2] is point B as indicated by arrow 32.
Feed diagonally downward from point C to point C (S2
8). This time, the shift amount a is in the opposite direction to the machining direction F in the XY direction, and the descending amount c [= (e + g-h) / 2] in the Z direction.
Only, as shown by arrow 33, the machining start point D of the shape from point C
The ball end mill 21 is moved in an obliquely downward direction to approach (S29). After that, the ball end mill 2 moves from the point D in the direction of the arrow F in the machining direction in order to perform the desired machining according to the machining data creation conditions based on the shape model.
Processing data for moving 1 is created (S30).

On the other hand, if NO in step S27, step S3
Go to step 3. Step S33 is the same Z approach as in the prior art, in which the shift amount from point B to point D is 0 in the XY direction, that is, at the same position as point B, and the shift amount in the Z direction is downward (b + c) [= e + g-h]. , From point B to point D (S33). When the Z approach ends in step S33, the process proceeds to step S30 to create machining data from point D (S30).

After step S30 of creating the processed data, step S31 follows. In step S31, NC data is created by the NC data creating unit 32 based on the approach conditions, the machining data, or the shape model data created above, and stored in the NC data memory unit 33 (S3).
1). This NC data is output via the output signal generation unit 14.
It is displayed on a display device such as the CRT 16 or is output to an output medium such as the FD 18 (S32).

Finally, processing using the zigzag approach will be briefly described with reference to FIG. FIG. 4 is a flowchart showing the flow of processing. First, the end mill 21 is placed at the point A (S41). Then, the end mill 21 is rotated and moved immediately downward from point A to point B by rapid feed to perform positioning in the Z direction (S42). Next, point B in the F direction, which is the processing direction
From the point to the point C, processing is performed obliquely downward at a specified feed rate (S43). Furthermore, from the point C to the point D in the direction opposite to the processing direction F.
Machining is also performed at a specified feed rate in the oblique downward direction up to and is moved to the cutting start position (S44). Finally, desired cutting is performed in the arrow F direction from the point D at the designated speed (S45), and the processing is completed. The finishing allowance h is processed separately in the next step.

The direction in which the ball end mill moves laterally (that is, the position of the point C) should be set at a position that does not affect the shape after processing, and the position of the point D is processed within the range of the machining allowance. You need to set the data.

Further, in this embodiment, the ball end mill was moved, but the effect does not change even if the workpiece is moved.

In the machining of the above-mentioned embodiment, the movement direction is changed twice at the points B and C to move the tool to the cutting start point (point D), but the movement direction is changed twice. However, the number of times may be increased.

[0029]

As described above, according to the NC program creating apparatus of the present invention, the zigzag approach method is enabled for the machining of the approach shape in which the tool has to be lowered directly onto the machining surface. When hitting the processing surface,
Since there are no cuts at which the cutting speed is 0, it is possible to prevent cutting teeth from cutting and biting into the workpiece during the Z approach. It was possible to remedy the shortcomings of. Furthermore, since it is possible to prevent bite, it is possible to greatly extend the life of the tool and to achieve a great effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an NC program creating device using the configuration of the present invention.

2A and 2B are shape model diagrams showing a zigzag approach of the present invention, FIG. 2A is a perspective view showing a concept at the time of processing, and FIG. 2B is a schematic view showing details of the approach.

FIG. 3 is a flowchart showing an operation of the NC program creating device shown in FIG.

FIG. 4 is a flowchart of processing including the zigzag approach method of the present invention.

FIG. 5 is a system block diagram of a conventional NC program creating device for the Z-direction approach.

6A and 6B are shape model diagrams showing a conventional approach portion in the Z direction, FIG. 6A is a perspective view showing a concept at the time of processing, and FIG.
It is a schematic diagram which shows the detail of an approach.

FIG. 7 is a flowchart showing the operation of an NC program creating apparatus showing a conventional Z-direction approach method.

[Explanation of symbols]

 8 Approach Condition Designating Section 20 Mold 21 End Mill 31 Zigzag Approach Creating Section 32 NC Data Creating Section 33 NC Data Memory Section

Claims (1)

[Claims] 1. A numerical control program creation for creating processing data based on a product shape, and creating processing data of a numerical control cutting machine for performing cutting by relatively moving a cutting tool and / or a workpiece according to the processing data. The apparatus is an approach condition designating unit that designates a calculation condition of an approach trajectory that is a trajectory that a cutting tool approaches from a cutting start position to a shape machining start position, and a cutting tool used by the approach condition designating unit is an end mill. A numerical control characterized by having a zigzag approach trajectory calculation unit that calculates an approach trajectory such that the approach trajectory always has a component in the end mill rotation axis direction and a component orthogonal to this rotation axis when specified. Program creation device.