JP2002108428A - Method for automatically generating input data for nc machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic input data generating method for NC machining which can prevent air cut by a machining cutting edge and overload to the machining cutting edge. SOLUTION: In the automatic input data generating method of an NC machining, a distance sensor 20 is fitted to an NC machine tool instead of the machining cutting edge, the real material shape of a forging material installed on the NC machine tool is measured by using the distance sensor 20. The machining work area of the forged material is specified based on the measured real material shape and the finish shape of the forged material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically creates input data suitable for NC turning of a forged material when the forged material is turned on an NC machine tool equipped with an automatic NC data program system. About the method.

[0002]

2. Description of the Related Art In turning a material with an NC machine tool, NC data for controlling the movement of the turning tool is required. For this reason, NC machine tools are provided with various automatic program systems that enable automatic creation of NC data. In any case, this kind of automatic program system uses the material shape data of the material and the finished shape data of the part obtained from the turning of the material as input data,
First, a turning region of the material is defined based on the material shape data and the finish shape data, and NC data is automatically created based on the turning region.

More specifically, when the material is a forged material obtained from free forging, the turning area is generally large, and therefore, the automatic program system uses the turning area to perform the turning in a plurality of times. NC data will be created.

[0004]

By the way, the input data of the material shape data and the finished shape data of the forged material are read from the forging diagram and the component diagram, respectively, and input to the automatic program system of the NC machine tool. But,
In the case of a forged material, the shape of the actual material after forging often differs greatly from the shape of the material on the drawing specified in the forged drawing.

That is, as shown in FIG. 1, when the shape of the forged material is indicated by a dashed line in the drawing, the shape of the actual material may greatly differ as indicated by the solid line. In such a situation, the turning area of the forged material is defined based on the finished shape data and the material shape data on the drawing, and when the forged material is turned on the basis of the turned area, FIG. In the α portion of the forged material in which the diameter of the actual material shape is smaller than the material shape on the drawing, even if the turning tool 2 of the NC machine tool is fed in the axial direction of the forging material, the turning tool 2 Turning of the forged material becomes invalid, and so-called air cutting of the turning blade 2 occurs.

Conversely, in FIG. 1, in the β part of the forged material in which the diameter of the actual material shape is larger than the material shape in the figure, the turning blade 2 starts turning of the forged material at an unexpected time. Therefore, the cutting speed and the feed speed are too high, and the turning by the turning blade 2 becomes severe. In the worst case, the load applied to the turning blade 2 may exceed the allowable range, and the turning blade 2 may be damaged.

In FIG. 1, reference numeral 4 denotes a face plate of the NC machine tool, and a forged material is mounted between the chuck jaws 6 of the face plate 2 and the center spindle 8. FIG.
The broken line in the middle indicates the finished shape. The present invention has been made based on the above circumstances, and the purpose thereof is to:
In order to prevent air cutting and severe turning with turning tools,
N to easily find the optimal turning area
An object of the present invention is to provide a method for automatically creating input data of C turning.

[0008]

In order to achieve the above-mentioned object, a method for automatically creating input data of NC turning according to the present invention (claim 1) is a method for mounting a forged material to be turned on an NC machine tool. , The turning tool of the NC machine tool is replaced with a distance sensor, and the distance sensor is moved in the axial direction while measuring the distance between the distance sensor and the forging material. Based on the measurement result in this measuring step Calculating the actual material shape of the forged material, and calculating the turning area defined between the finished shape of the part obtained by turning from the forged material and the calculated actual material shape, and performing this turning. An input data generating step of outputting a machining area as input data of NC turning.

According to the above-mentioned method for automatically creating input data,
The distance sensor attached to the NC machine tool instead of the turning blade can be moved along the axial direction of the forged material by the NC machine tool, and the actual material shape of the forged material can be easily measured. The actual material shape measured in this way is compared with the finished shape of the part, whereby the turning area by the turning tool is calculated, and this turning area is output as input data of NC turning, that is, as described above. Supplied to an automatic programming system.

Specifically, in the above-described measuring step, the maximum outer diameter and the minimum outer diameter for each cross section of the forged material are measured by rotating the forged material one or more times during the measurement by the distance sensor, and In the calculation step, the maximum material shape obtained based on the maximum outer diameter of each cross section of the forged material is calculated as the actual material shape (claim 2). The turning area calculated from the actual material shape and the finished shape calculated in this way is optimal for avoiding severe turning by the turning blade.

Further, the calculating step further calculates a minimum material shape obtained based on a minimum outer diameter for each cross section of the forged material, and the method compares the minimum material shape with a finished shape. It is preferable that the method further includes a determination step of determining the quality of the forged material based on the above.
In this case, when the determination step detects a portion where the minimum material shape is smaller than the finished shape in terms of the diameter, the forging material is determined to be defective, and thereby, unnecessary turning of the defective forged material is performed. Is prevented.

[0012]

FIG. 2 schematically shows an arrangement for carrying out the method of the present invention. An NC machine tool 10 such as an NC lathe or an NC vertical lathe and an automatic program system 12 are provided with a data generation controller (hereinafter, referred to as a data generation controller). (Referred to simply as a controller) 14. The automatic program system 12 automatically creates NC data for turning based on the input data output from the controller 14, and supplies the NC data for machining to the NC machine tool 10.

The controller 14 includes a microprocessor (MPU), a microcomputer having a memory such as a ROM and a RAM, an input / output interface, and an input device such as a keyboard. The controller 14 can supply the finished shape data of the part and the on-line material shape data of the forged material to be turned, and the finished shape data and the on-line material shape data can be supplied from the part diagram and the forged diagram, respectively, as described above. It will be read and provided to the controller 14 via the input device.

On the other hand, a distance sensor 20 can be attached to the NC machine tool 10 instead of the turning tool. The distance sensor 20 is a non-contact type distance sensor such as a laser distance sensor and an ultrasonic distance sensor, and supplies a detection signal to a control unit of the NC machine tool. The control unit obtains the actual material shape of the forged material based on the detection signal from the distance sensor 20 and supplies the actual material shape data to the controller 14 as described later.

When the distance sensor 20 is attached to the NC machine tool and a forged material is mounted between the chuck jaws of the face plate and the center spindle, the controller 14 is turned on.
Performs the data generation process shown in FIGS. Prior to the mounting of the forging material, the outer periphery of one end of the forging material gripped by the tick claw and the other end surface receiving the contact of the center spindle have already been turned according to the finished shape.

First, the controller 14 sequentially reads the supplied finished shape data and the supplied raw material shape data (steps S1 and S2). Here, in FIG. 6, the finished shape is AB
Assuming that a shape element of a broken line connecting CDEFG sequentially is represented and a material shape on a solid line is represented by a shape element of a solid line connecting GHIJA, the finished shape data and the material shape data on the drawing are shown in Table 1 below. expressed. In FIG. 6,
The Z axis is a center axis connecting the axis of the chuck jaw of the NC machine tool and the center spindle, and the X axis indicates a radial distance from the center axis.

[0017]

[Table 1]

When the controller 14 receives the finished shape data and the raw material shape data on the drawing, the controller 14 creates NC data for scanning of the forged material based on these data, and transmits the NC data for scanning to the NC machine through the automatic program system 12. It supplies to the machine 12 and controls the scanning by the distance sensor 20. Specifically, the controller 14 first divides the Z-axis length L of the forged material between point G and point A from the finished shape data into a predetermined number of samplings N, and assigns L ₀ , L ₁ …, L _N (step S
3) After that, an offset material shape G ′ → J ′ obtained by offsetting the material shape G → J on the drawing by a predetermined distance S in the X-axis direction.
(A two-dot chain line in FIG. 6) is generated (step S4). Here, the distance S is within the allowable measurement range of the distance sensor 20 described above, and is set to a value sufficiently larger than the maximum diameter difference between the forged material and the shape of the material on the drawing.

Thereafter, the controller 14 sets each equal point L
i (i = 0~N) parallel to the line segment and passing by and X-axis is find the intersection between the offset material shape G '→ J', each intersection measurement position _{M 0, M 1 ..., M} N (Step S
5). When the measurement position Mi (i = 0 to N) is set in this manner, the controller 14 supplies a movement command of the distance sensor 20 to the control unit of the NC machine tool 10 through the automatic program system 12, and controls the distance sensor 20. Measurement position M
₀ (corresponding to the coordinate position of point G ′ in the offset material shape G ′ → J ′) (step S6).

Next, the controller 14 resets the variable j to 0 (step S7), and after incrementing the variable j by 1 (step S8), the control unit of the NC machine tool 10 through the automatic program system 12. , A movement command of the distance sensor 20 is supplied, and the distance sensor 20 is moved to the measurement distance Mj (step S9). In this state, the controller 14 supplies a rotation command of the forging material to the control unit of the NC machine tool 10 through the automatic program system 12 to rotate the forging material one or more times, and activates the distance sensor 20 during this rotation. Then, the separation distance between the measurement position Mj measured by the distance sensor 20 and the forging material through the control unit is continuously captured, and the captured separation distance is temporarily stored in the memory (step S10).

Thereafter, the controller 14 obtains the maximum value and the minimum value from the data of the separation distance stored in the memory,
These are calculated as the maximum outer diameter Xjmax of the forged material at the measurement position Mj,
It is stored in the memory as the minimum outer diameter Xjmin (Step S1)
1). Here, the maximum outer diameter Xjmax and the minimum outer diameter Xjmin are caused by a roundness error, bending, runout, or the like of the forged material. Next, the controller 14 determines whether or not the variable j has exceeded the sampling number N described above (step S12). If the determination result is false (No), the steps from step S8 are repeated. .

Thereafter, the result of the determination in step S12 is true (Y
es), the controller 14 stores in the memory the maximum outer diameter Ximax and the minimum outer diameter Xim of the forged material at the measurement position Mi.
in will be stored. And the controller 14
Calculates the maximum material shape of the forged material based on the maximum outer diameter Ximax at each measurement position M, and similarly calculates the minimum material shape of the forged material based on the minimum outer diameter Ximin (step S13). Here, the maximum material shape and the minimum material shape are indicated by a two-dot chain line and a one-dot chain line in FIG. 7, respectively.

The maximum material shape and the minimum material shape are represented in the data format in the same manner as the finish shape data and the material shape data on the drawing, as shown in Tables 2 and 3 below.

[0024]

[Table 2]

[0025]

[Table 3]

In Tables 2 and 3, .DELTA.Pi and .DELTA.Qi indicate the shape elements of the portion corresponding to the measurement position Mi, respectively.
Thereafter, the controller 14 sequentially executes the correction processing of the maximum material shape data and the minimum material shape data (Steps S14 and S15). Specifically, the correction of the maximum and minimum material shape data is performed as follows.

In the case of maximum material shape data (step S1)
4), controller 14 is P_NTo P₀Each shape required for
The elementary X coordinate value is scanned, and the k-th X coordinate value is changed to the next (k +
If it is larger than the 1) th X coordinate value, the (k + 1) th
Is replaced with the k-th X coordinate value. like this
By repeating the replacement operation, the controller 14 _NOr
R₀Find the maximum material shape that expands uniformly toward
The maximum material shape after correction is larger than the actual material shape of the forged material.
It will be slightly larger.

On the other hand, in the case of the minimum material shape data (step
Step S15), the controller 14₀To Q_NTowards
The X coordinate value of each shape element is scanned, and the k-th X coordinate value is
Is smaller than the (k + 1) th X coordinate value of
1) Replace the Xth coordinate value with the kth X coordinate value. This
Is repeated, and the controller 14 ₀
To Q_NFind the minimum material shape that uniformly reduces toward
The minimum material shape after this correction is greater than the actual material shape of the forged material.
Is also slightly smaller.

Then, the controller 14 calculates the minimum turning area by combining the corrected minimum material shape data and the finished shape data (step S16). This minimum turning area can be indicated by a hatched area in FIG. This minimum turning area can also be represented as similar shape data. And the controller 1
4, after turning the forged material, based on the calculated minimum turning area, it is determined whether or not the finished part has underfill (step S17).

More specifically, in step S17, the controller 14 subdivides the minimum turning area in FIG. 8 into a plurality of turning scanning lines in the X-axis direction (cutting direction of the turning blade), and For each scanning line, the intersection between the measure scanning line, the minimum material shape and the finish shape is determined. That is,
Assuming that one turning scan line is indicated by R in FIG. 8, the turning scan line R intersects the minimum material shape and the finished shape at intersections R ₁ and R ₂ , respectively. Intersecting points R ₁ . R ₂ , that is, these intersections R ₁ . And it compares the Z coordinate of R _2, wherein, if larger is than the intersection point R ₁ is the intersection R _2, can be turned in the forging material by turning cutting tool is determined to be valid. Then, when the controller 14 confirms the validity of the turning for all the turning scan lines,
The determination result of step S17 is set to false.

On the other hand, as shown in FIG.
When _one of Z coordinate is smaller than the Z coordinate of the intersection R _2, since the turning according turning cutting tool in this portion is disabled, underfilling the part after turning (forging material failure) occurs, the In this case, the controller 14 sets the determination result of step S17 to true. If the determination result of step S17 is false,
The controller 14 calculates the maximum turning area by combining the maximum material shape data and the finish shape data, and outputs the calculated maximum turning area to the automatic program system 12 as input data (step S18).
Note that the maximum turning area is also represented by similar shape data.

On the other hand, if the result of the determination in step S17 is true, the controller 14 determines that the forged material to be turned is defective and outputs a defective signal (step S1).
9). Upon receiving the supply of the maximum turning area, the automatic program system 12 automatically creates NC data for turning the forged material in a plurality of times based on the maximum turning area. Thereafter, in the NC machine tool 10, the above-described distance sensor 20 is replaced with a suitable turning tool, and the NC machine tool 10 turns the forged material based on the NC data automatically created by the automatic program system 12. I do.

Since the maximum turning area is calculated based on the finished shape and the actual material shape of the forged material, not on the diagrammatic material shape of the forged material, the air cutting by the turning blade tool during the turning operation is performed. Is minimized, and overload applied to the turning tool is also effectively prevented. In other words, since the maximum turning area is indicated by a hatched area in FIG. 10 that rises to the right, even if there is a portion V that protrudes from the maximum turning area in the raw material shape in FIG. Air cutting of the turning blade is reliably prevented.

Conversely, even if there is a region Y which is larger than the material shape in the drawing in the maximum turning region, turning can be performed satisfactorily in this region Y, and an overload is applied to the turning blade to cause breakage. Nothing. Further, in the present embodiment,
In step S17 described above, the controller 14 determines the presence or absence of the underfill, so that if the determination result is false, the calculation of the maximum turning area is not wastefully performed. Further, upon receiving the output of the failure signal from the controller 14, the turning of the forged material can be stopped,
There is no need to cause the NC machine tool to perform useless turning.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the present embodiment is applied to a forged material whose outer shape uniformly expands or contracts in the Z-axis direction.
As shown in FIG. 1 and FIG. 12, a forging material having a concave portion or a convex portion on a part of its outer periphery is also applicable. In this case, the forged material is divided in the Z-axis direction, the actual material shape is measured for each of the divided portions, and a turning area is calculated based on the measured actual material shape.

In the above-described embodiment, the automatic program system 12 and the data generation controller 14 are provided separately. However, the function of the automatic generation program system 12 may be added to the data generation controller 14. Finally, the present invention is not limited to the NC lathe, but is applicable to various NC machine tools that perform turning.

[0037]

As described above, according to the method for automatically creating input data of NC turning according to the present invention (claim 1), the actual material shape of the forged material to be turned is measured, and the measured actual material shape is measured. Since the turning area is calculated from the finished shape and the finished shape, turning of the forged material can be performed satisfactorily, and air cutting by the turning tool and overload applied to the turning tool can be prevented, enabling economical turning. Become.

Since the actual material shape can be measured only by attaching a distance sensor instead of the turning tool of the NC machine tool, the measurement can be easily performed. Further, when the actual material shape of the forged material is the maximum material shape obtained from the maximum outer diameter in each cross section of the forged material (claim 2), the air cut and overload can be more effectively prevented.

Further, since the minimum material shape of the forged material and the finished shape are compared in advance (claim 3), useless turning of the forged material can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a conventional problem.

FIG. 2 is a block diagram showing a relationship between an NC machine tool and a data creation controller.

FIG. 3 is a part of a flowchart executed by the data generation controller of FIG. 2;

FIG. 4 is a part of a flowchart executed by the data generation controller of FIG. 2;

FIG. 5 is a part of a flowchart executed by the data generation controller of FIG. 2;

FIG. 6 is a diagram showing a procedure for measuring an actual material shape of a forged material.

FIG. 7 is a diagram showing the measured maximum material shape and minimum material shape together with the actual material shape.

FIG. 8 is a diagram showing a minimum turning area.

FIG. 9 is a diagram for explaining the presence or absence of underfill.

FIG. 10 is a diagram showing a maximum turning area.

FIG. 11 is a view showing a forged material of a modified example.

FIG. 12 is a view showing a forging material of another modification.

[Explanation of symbols]

 Reference Signs List 10 NC machine tool 12 Automatic program system 14 Data generation controller 20 Distance sensor

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Claims (3)

[Claims] 1. A method according to claim 1, wherein the forging material to be turned is mounted on an NC machine tool, and a turning tool of the NC machine tool is replaced with a distance sensor. A measuring step of measuring a distance between the forged material, a calculating step of calculating an actual material shape of the forged material based on the measurement result in the measuring step, and a part obtained by turning from the forged material An input data generating step of calculating a turning area defined between a finish shape and the calculated actual material shape, and outputting the turning area as input data of NC turning. Method of automatically creating input data for NC turning. 2. The measuring step comprises rotating the forged material one or more times during the measurement by the distance sensor,
Measuring the maximum outer diameter and the minimum outer diameter of each cross section of the forged material, and calculating the maximum material shape obtained based on the maximum outer diameter of each cross section of the forged material as the actual material shape. 2. The method for automatically creating input data of NC turning according to claim 1, wherein: 3. The calculating step further calculates a minimum material shape obtained based on a minimum outer diameter of each cross section of the forged material, and compares the minimum material shape with the finish shape. The method for automatically creating input data of NC turning according to claim 2, further comprising a determination step of determining the quality of the forged material based on the following.